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US3069254A - Autogenous pyrometallurgical production of nickel from sulfide ores - Google Patents

Autogenous pyrometallurgical production of nickel from sulfide ores Download PDF

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US3069254A
US3069254A US51438A US5143860A US3069254A US 3069254 A US3069254 A US 3069254A US 51438 A US51438 A US 51438A US 5143860 A US5143860 A US 5143860A US 3069254 A US3069254 A US 3069254A
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nickel
bath
oxygen
sulfur
copper
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US51438A
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Queneau Paul Etienne
Renzoni Louis Secondo
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Huntington Alloys Corp
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International Nickel Co Inc
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Priority to NL129554D priority Critical patent/NL129554C/xx
Priority to NL120731D priority patent/NL120731C/xx
Priority to NL255774D priority patent/NL255774A/xx
Priority to US51438A priority patent/US3069254A/en
Application filed by International Nickel Co Inc filed Critical International Nickel Co Inc
Priority to FR838143A priority patent/FR1274967A/en
Priority to DEJ21254A priority patent/DE1139981B/en
Priority to GB31367/60A priority patent/GB960698A/en
Priority to GB31368/60A priority patent/GB960699A/en
Application granted granted Critical
Publication of US3069254A publication Critical patent/US3069254A/en
Priority to NL6412531A priority patent/NL6412531A/xx
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B23/00—Obtaining nickel or cobalt
    • C22B23/02—Obtaining nickel or cobalt by dry processes
    • C22B23/025—Obtaining nickel or cobalt by dry processes with formation of a matte or by matte refining or converting into nickel or cobalt, e.g. by the Oxford process

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  • the pre-sent invention relates' to an" improved process for' the smelting ⁇ ⁇ and reii'ning of nickel- ⁇ and copper-containing sulfide materials for the direct recovery .of metallic nickel or nickel-copper y'alloys therefrom.
  • the Bessemer converter isiernployedinithe'copper ⁇ in# dustry. to convert copper sulideto metalliccopper.n
  • theart also depends on the use' of ⁇ the Bessemer concept' involving ⁇ anV airblastbe-v low themolten matte level through tuyeres.V
  • thekairV must be-'highly preheated or oxygena-ted or fuel must'be Ialledto* maintain the required reactiomtemreratures.
  • Another object of thetinvention is to provide a method fo'r producing metallic nickel directly from nickelfrich sulde materials such .as mattes by inducing turbulence of the liquid material and by impinging processt gases ont-he physically andcheriicallyV active surface thereof.
  • the invention also contemplates providing novel process for the direct reduction of substantially iron-free nickel matte's to nickel metal fanodes.
  • the invention further contemplates providing ⁇ novel methods for separatingcopper and cobalt from low iron'- nickel mattes and for reducing ⁇ the nickel suhide directly to metallic nickel.v y
  • FIG. 3 shows'a'diagrammatic!cross-section through a liquid-liquid extraction column ili'which copper maybe separated from-nickelV sulfides by the special solventy extraction ⁇ process described hereinafter.
  • nickel-containing sulfide 'materials such as* nickelA matte andv crud nickel sulfide precipitates such as "those obtained by ore'wleachiig techniques are smelted autogenously in arotarykilriltyp furnace to a matte, This is'followed'bytop-blowi gth matte so obtained'in the same"autognous,”rotaryfkiln; type' furnace using commercial oxygen' or xygeii-eh- ⁇ riched air directed' down onto the surfaceofthe'nliolten bath butI not throughgthe metal frombelow' theliquid leveh
  • Voxygen supplyand'bathtem peratnre and by strong-mechanically-induced agitation of-the bathwthe molten nickel sulde is reduced ,to sub-V staritdially" sulfur-free nickel metal.
  • blowing' and mechanical agitation of the bath are controlled'each in ⁇ dependent of Athe other.
  • Control ⁇ of oxygen ,supplyf and of turbulence is such las to maintain satisfactory' bath iluidity land uniformityA lto permit rapidj 4nickel sulfidenickel oxide reaction and high efficiency of oxygen divulg. tionl while maintaining the' temperature below, that at whichundueirefractory attack isI experienced.
  • the turbulence in the bath is mandatory to insure bath uniformity, both physical and chemical, so as to give quick reaction towards equilibrium, e.g., the nickel oxidenickel sulfide reaction.
  • sulfur in the molten bath may be eliminated to less than about 0.05% sulfur, e.g., 0.01% sulfur. It will be understood of course, that alternatively standard desulfurization techniques can be employed for final sulfur removal.
  • the blowing operation may be conducted initially at temperatures not greatly above the melting point of the nickel sulfide-containing material and at this stage advantage is taken of the exothermic heat of reaction to smelt solid feed if desired.
  • the temperature is raised as desulfurization proceeds until, at a sulfur content of the bath of less than 4%, advantageously between about 1% and about 3%, a temperature between about 3000 F., and 3200o F., is attained and maintained until final sulphur elimination is achieved. It will be understood that if the nickel contains a substantial proportion of copper, final ytemperatures will be significantly lower.
  • nickel matte which may contain less than about 1% iron, the amount of copper remaining after conventional separation of copper by ore dressing means, e.g., one part of copper to ten parts of nickel, and some cobalt and precious metals, e.g., one part of cobalt to 25 parts of nickel and 2 ounces of precious metals per ton of nickel, is treated, if desired, for the removal of the copper, cobalt and precious metals as hereinafter described.
  • the matte is then transferred to the autogenous reduction furnace wherein it is top blown with oxygen to nickel metal.
  • the autogenous reduction operation may be carried out in the furnace depicted in FIG. l and FIG. 2 of the accompanying drawing which show a long token section of the furnace and a cross-section of the furnace through line 2-2 of FIG. 1, respectively.
  • the molten, nickel sulfidecontaining material is treated in a rotary kiln-type furnace 11 which is lined with high-grade refractory brick 12.
  • the furnace may be tilted as desired for tapping by using tilting mechanism 20.
  • the furnace has tires or drive rims 13 aixed circumferentally around it and these tires rest on supporting or drive wheels 14.
  • Oxygen or oxygen-enriched air is supplied by a water-cooled tube or pipe 15 which projects through seal 21 and opening 16 into the furnace.
  • the reduction operation need not be conducted in the apparatus as specifically shown in FIG. 1 and described hereinbefore providing the apparatus meets the operational requirements as outlined herein, e.g., it may be carried out in a top blown converter such as the Kaldo furnace.
  • Nickel matte which is substantially iron-free may be blown directly to metallic nickel after copper removal, if necessary, from the molten material as described hereinafter. Precious metals may be removed as described hereinafter before blowing directly to metallic nickel.
  • the sulfide material which has been charged into the furnace is treated by bringing oxygen or oxygen-enriched air into direct contact with its surface.
  • This gas which advantageously is initially commercial oxygen, is blown into the furnace above the surface of the molten material. Necessary bath turbulence is maintained by continuous rotation of the furnace at a substantial speed.
  • the temperature of the bath is kept high enough to keep the reacting materials in a sufficiently fluid state to permit rapid reaction and yet below the temperature at which undue refractory penetration or erosion is experienced.
  • the furnace blow may be started at a temperature of as low as 1550 F.
  • 1550 F. e.g., 2500 F.
  • the temperature must be high enough to keep the slag in a fluid state.
  • the temperature of the bath is rapidly raised until the sulfur content of the bath has been lowered to preferably between about 1% and about 3% and a bath temperature of more than about 2800 F. has been attained. It has been found that the temperature of the reduction operation and, in fact, the operation in general is controlled by varying the oxygen supply, by observing exhaust gas analysis and temperature and by varying turbulence.
  • Cooling may be otherwise accomplished or may be supplemented by adding water to the gas stream rather than air or by adding solid charge to 4the furnace or by a combination of these techniques.
  • the. oxidizing. gases. should be. replaced, as. aforestated, by substantially sulfur-free oxygen-impoverished gases, e.g., neutral or somewhat reducing gases while heating or maintaining the molten. bath to a temperature of between ⁇ about 3000 F. andV about 3,200o F.
  • the neutral or reducing gases must be at; a high temperature and this is best accomplished by adding aV highly combustible. ⁇ fuel such as natural gas on propane together with the oxygen. The fuel consumes any excess oxygen and generates a high temperature flame so that undue formation of nickel oxide isthereby ⁇ prevented..
  • Theimpinging gases may thus advantageouslyI and. gradually be decreased in. oxygen content from that of commercial. oxygen, to: oxygen-enriched f air., to air; to oxygen-impoverishment, to non-oxidizing or inert. and finally: to somewhat reducing.
  • oxygen-enriched f air. to air
  • oxygen-impoverishment to non-oxidizing or inert. and finally: to somewhat reducing.
  • The. exact oxygenI content of the. gas is ⁇ variable determined. by and ⁇ within the. control: of the furnace operator.; It has been: found that during this final desulfurization periodbest resultsV are obtained by. increasingbathturbulence; especially if for any reason the bath: hasV become over-oxidized:
  • the surface ⁇ of the molten bath shouldbekept free of slag or scum.
  • the oxidizing gasesinthe furnaceA preferablyshould' be replaced by, nonfoxidi'zing gases before sulfur.. elimination; has proceeded tofbelwaboutl%-sulfur; e.g. ⁇ , 2% sulfur: Deoxidation ofsthe molten bathaftersulfur" removal may be readily carried out .by carbon addition to the furnace.
  • Graphite has been foundto be an excellent deoxidizing agentcalthoughother: deoxidantsf such'asisilicon or'aluminum .mayl be utilized.
  • a high residualIoxygencontentfin theibathl should; of course, be ⁇ avoided since'large quanti* ties oficostly deoxidizing ⁇ agents ,are requiredand ⁇ possiblyy violent; reactions may foccur;
  • nickelY -sulde to metallic nickel can be attained with very smalll nickellosses due either to slagging as oxide; or. to'dustingin exhaust gases, i.e., ⁇ ⁇ a nickely yield' in excess of 99%.
  • slagj produced during the first stage of iron eliminationwliicli is low in nickel i-s removed and treated for recovery of its nickel content, if desired)A and the slag produced duringrthefmal-stage.oflironeliminationisleft.in thecfumace. for. recovery of itsinicke'l content upon further addition of'l concentrate-tori matte.M After af complete charge of molten matte rhas-'been built up in the autogenous furnace, slag produced from final iron elimination is removed and Imay be. treatedV in parallel' autogenous reduction furnac'effor treatment with;v fresh sulfide.
  • the copper advantageously should:;be removed before ⁇ desulfurizing. treatmentv in the top blowna: reduction furnace.l ⁇ Coppersremoval..byfmeans ofsa novelsolvent extraction process, ie., high temperature liquid-:liquid extraction, has been found particularly advantageous.
  • nickel sulfide with a substantial copper content e.g., a ratio of nickel:copper of, for instance, 10:1 can be treated for copper .removal to produce a nickel sulde having a residual copper content of less than 0.10%, e.g., with a ratio of nickelzcopper of at least about l000:1.
  • nickel sulfide ores containing copper can be concentrated by flotation so that the bulk of the nickel is in a concentrate containing nickel and copper in a ratio of at least about 10:1 which can be readily decopperized by our novel procedure.
  • Much higher copper contents can be extracted by this method if simpler prior separation, eg., of the natural minerals by flotation, is impractical.
  • This novel molten salt solvent extraction technique is based on the use of sodium sulfide as the selective agent, probably a complexing agent, for copper sulfide.
  • This agent is dissolved in molten sodium chloride in which solution nickel has only a slight solubility and copper a high solubility.
  • An essential feature of this salt cornbination is its relatively low melting point of below about 1300 F. This permits the solvent extraction to proceed at a temperature as low as about 1350 F. Thus, the extraction is carried out close to the melting point of the metal sulfides which is the optimum temperature for liquid copper-nickel separation. This low operating temperature and the high water solubility of the extractant have the additional important advantages of economy in reagent, fuel and refractories consumption.
  • This novel separation technique is outstanding in that sequestration of copper by the solvent and isolation of nickel are both highly effective while the cost of labor, supplies and equipment is relatively low.
  • Our procedure permits economical removal of co-pper sulfide, entirely beyond the capability of the existing art, from sulfides having a broad range of nickel to copper ratios to yield nickel sulfide having a nickel to copper ratio of greater than l000:1.
  • chloride modifiers such as the chlorides of potassium, calcium and aluminum may be employed.
  • the nickel sulfide material and sodium salts are advantageously melted at not below about 1350 F. and not above about 1550 F., carefully mixed to insure excellent countercurrent liquid-liquid contact and then separated by gravity into copper-rich and nickel-rich fractions.
  • a preferred apparatus for this purpose is a liquid-liquid extraction column as shown in FIGURE 3.
  • the substantially copper-free nickel sulfide product may be air blown for slagging of residual sodium salts and then transferred directly to the autogenous reduction furnace to be blown to metallic nickel as described hereinbefore.
  • the copper-sodium rich product may be treated by water leaching to recover copper and the sodium salts and residual nickel.
  • the extraction may be carried out in other apparatus, e.g., in an appropriately designed, countercurrently operated rotating kiln or by simple ladle mixing, settling and bottom pouring in a countercurrent multi-stage operation.
  • the advantageous results obtained by our novel solvent extraction technique rfor extracting copper from nickel sulde are shown in Examples II and III.
  • EXAMPLE III A nickel matte containing 4.8% copper with the balance mainly nickel and sulfur was treated for copper extraction in the same way as in Example II except that the countercurrent extraction was conducted at 1400 F.
  • the final products from the four-stage treatment analyzed as follows:
  • FIGURE 3 which depicts. the diagrammatic cross-section of a baille plate column in which theV copper-containing nickel sultide is treated with themolten salt mixture for elimination of copper.
  • solid baffle plates. 30, which extendpartially across the colunmcrosssection, are placed at suitable intervals in the column.
  • Molten copper-containing nickel sulfide from storage tank 31- ⁇ is introduced through line 32' and variable orifice 33 into the top ofthe column at 34.
  • Molten sodium saltsolvent from storage tank 35 is introduced through line- 36 and: variable torque 3l'7 ⁇ into ⁇ the bottom ofthe column at 3S.
  • Nickel sulfide from whichl copper has been eliminated. is drawn olf the. bottom of the ⁇ column throughv line 39s and. variable perennial nervous 40.
  • Copper-rich solvent is drawn off- ⁇ the top ofthe column-through line 41.
  • HeatY is. supplied tothe column and ⁇ to the tanks-31 and 35' tov maintain the sulde and sodium salts in a molten condition and at the separation temperature desired such as byway of electric immersion heaters 42 and external electric heaters 43;
  • the heavier nickel sulfide flows along eachbaille, which is. supplied with ⁇ a short lip 44 so that each is substantially a tray, overiiows over the lip and then flows downward tothe next tray;
  • the lighter sodiumsalt solvent flows upwardV around each baille and throughthe free area between the tray and the inside wallsV of the column
  • the. moltennickel matteY from.i which thecopper has advantageously-been ext-racteddownt to below about 0.310% copper may-betransferredto theV autogenpus reduction; furnace, preferably after residuale sodium salts, have been removed by ra brief, relatively lowtemperature, airblow in a separate vessel and decantedr for reuse.
  • the precious metals may be removed by known meansA such as by blowingpto create a sulfur deficiency, cooling, solidifying, grinding and removing the, precious ⁇ metals, concentrated in the metallics.
  • The. ⁇ nickel sulfide may then be, water leachedto. remove sodium salts, dried land then fed directlytov the autogenousl reduction kiln.
  • cobalt elimination may be accomplished during 4conversion of the; sulfide, material to metal by blowing the molten material with an oxygenrich gas at a sulfur content off; more than about 3% to selectively oxidize the cobalt in the presence of a ilux such as silica.
  • the cobaltr is then skimmed' off.' as slag.
  • the sulfur content of the molten charge is maintained at above about 3% sulfur by continuously adding fresh sulfide material' to the autogenous reduction furnace while top-blowing at between about 2300-o F; and about2800 F24 for sulfur :and cobalt removal'.
  • EKA-MELE V A suhideorecontaining nickel; copper, cobalt; ironand-gangueminerals was treated by conventional methods to produce a concentrate containing-12.0% nickel, 1.6%-
  • EXAMPLE VI 4:4 ⁇ tonsof a ⁇ molten nickel matte containing. 70.9%v nickel, 4.8% copper, 1.0% iron and 23.3% sulfur were topblown with-,oxygen in a furnace, similar to that-shown in FIGURE l2, rotating at 20'r.p.m. at a temperature rising to 3000 F. Cooling was accomplished4 by itijecting air with the oxygen. The molten material was blown down to 1.4% sulfur at which point propane gas was injected with the oxygen and rotation of the furnace was increased to r.p.m. Enough propane was injected to produce a somewhat reducing atmosphere in the furnace. The temperature of the bath rose to and was held at about 3l00 F.
  • pentlandite concentrate may be oxygen-flash smelted to a nickel matte, as disclosed by one of the present inventors in U.S. Patent No. 2,668,107.
  • Our new process is an improvement over that described in this patent in that our product is metallic nickel instead of nickel matte with a high impurities content.
  • the slag produced during the first stage of iron elimination, low in nickel, is removed from the furnace and the slag produced during the final stage of iron elimination is left in the furnace for extraction of its nickel content upon further addition of concentrate.
  • the molten material may be treated for copper removal and Iit is then blown directly to metallic nickel both of which operations are above described in detail.
  • An improved process for autogenously converting a nickel sulfide material to produce nickel of low sulfur content which comprises directing oxidizing gases from the group consisting of commercial oxygen and oxygenenriched air into the exposed surface of a molten bath of said sulfide material, while avoiding sidewall and bottom blowing of said gases through the bath, and maintaining the bath during the converting in a state of turbulence with non-pneumatic, mechanically induced agitation, said agitation being maintained during the directing of said oxidizing gases, to promote intimate and efficient gas-liquid-solid contact and uniform distribution of oxygen throughout the bath and its rapid reaction with sulfur therein; raising the bath temperature as desulfurization proceeds to more than about 2800 F.; changing said gases being introduced into the bath surface to hot, substantially sulfur-free gases from the group consisting of neutral and reducing gases having an Oxygen content insufficient to cause visible formation of interfering amounts of nickel oxide dross on the surface of the bath when the sulfur content of the bath is still substantial but is less than about 4% and the
  • An improved process for autogenously converting a nickel sulfide material to produce refined nickel. of low sulfur content which comprises blowing commercial oxygen onto the exposed surface of a molten bath of said sulfide material While avoiding sidewall and bottom blowing of said oxygen through the bath, and maintaining the bath substantially slag free during the blowing with oxygen and in a state of turbulence with mechanically induced agitation, said agitation being maintained during the blowing, to promote intimate and efficient gas-liquid-solid contact and uniform distribution of oxygen throughout the bath and its rapid reaction with sulfur therein and to produce off-gas rich in sulfur dioxide; raising the bath temperature as desulfurization proceeds to more than about 2800 F.
  • the improvementW which comprises autogenously smelting the nickel matte by blowing commercial oxygen onto the exposed surface of a molten ba-th4 of said nickel matte at atemperature ofV at leastabout 2400 F., while avoidingsidewall and bottom blowing of said oxygen through the bath, and maintainingthe'bathv 4substantially free of slag during the blowing with oxygen and in a state of turbulence with mechanically induced agitation, said agitationJ being maintained during the blowing, to promote intimate and efficientl gas-liquid-solid contact and uniform distribution ofoxygen throughout the bath and its rapid reaction with sulfur therein; raising.
  • the bathtemperaturel as desulfurization proceeds tomorethan about 2800 F; while continuing. said blowing with oxygen; changingsaid oxygen being directed onto the molten bath to hot gases from the group consisting of neutral and reducinggases substantially free of sulfur dioxiden and having. an oxygen content insufficient to cause visible formation of interfering amounts of nickel-z oxideA dross on the surface of the bath when its sulfur content ⁇ is between about 1% and -about 3%.
  • ⁇ and its oxygen contentr is at least ⁇ sufficient to oxidize the sulfur content, the bath. being at. a temperature of'between about 3.0009 F; and' 3200"v F.
  • Ant autogenous process for producing refined metallic nickel directly from nickel-rich sulfide materials containing iron which comprises directing commercial, oxygenA onto the surface of'a molten bat-hof said nickel-rich sulfide material while avoiding sidewall and bottom blowing of said oxygen through the bath, said bath being maintained in a state ofturbulence by mechanically in quiz food, said artist's hand, said blender's hand, said blender's hand, said blender'sulfide material while avoiding sidewall and bottom blowing of said oxygen through the bath, said bath being maintained in a state ofturbulence by mechanically in quiz agitation, saidagitation being maintained during the directing of" said oxygen, to oxidize iron ⁇ and.
  • An improved process for- -au-togenously converting a nickel-copper sulfide material to produce nickelecopperalloy of "low sulfur content which comprises directingoxygen-rich gases from the group consisting of commercial ⁇ oxygen and oxygen-enrichedair into the. exposed sur-face tof-V a moltenf bath of said sulfide material, while avoiding sidewall and ⁇ bottom blowing ofsaid gasesA through the bath, and maintaining the. bath during the converting. in a state of turbulence.
  • oxide dress en tbe surface-,i nf the; nieleelnepree alley. beth. nnen, c bensfL ing fingern Oxygen-cicli; gases; and; maintaining the bien temperature in tbe, beth. in tbe. presence. ciy said bet ariseste. centinne tbe reaction between sulfur; and. Oxygen. in. thetnrbnlent; beth and te, Produce nickel-copper.- aller with, al sulfur.. content loWl uQllgh below 0.5,% for re-A moval; b y. desulfurizatiorn.
  • the improvement which comprises melting and mixing between about one-half to double by weight of a salt mixture of sodium sulfide and a metal chloride from the group consisting of sodium chloride, potassium chloride, calcium chloride and aluminum chloride with said nickel sulfide material inthe molten state; allowing said molten mass to separate into an upper copper sulfide-salt mixture liquid phase and a lower nickel sulfide liquid phase; separating said liquid phases; treating said upper liquid phase for recovery of the salt mixture contained therein; oxidizing and removing salt mixture from the lower, nickel sulfide liquid phase; and treating said nickel sulfide liquid phase for recovery of the nickel contained therein.
  • the improvement which comprises melting and mixing between about one-half to double by weight of a mixture of sodium chloride and sodium sulfide salts containing between about 25 and about 75% sodium chloride with said nickel sulfide material in the molten state at a temperature of not below about 1350" F.
  • the improvement which comprises melting and mixing between about one-half to double by weight of a salt mixture of sodium sulfide and a metal chloride from the group consisting of the chlorides of sodium, potassium, calcium and aluminum with said nickel sulfide material in the molten state; allowing said molten mass to separate into an upper copper sulfidesalt mixture liquid phase and a lower nickel sulfide liquid phase; repeating the foregoing operations in a countercurrent manner; separating the final liquid phases; treating the upper liquid phase for recovery of the copper and the salt mixture contained therein; oxidizing and removing salt mixture from the final, lower, nickel sulfide liquid phase; directing commercial oxygen onto the exposed surface of a molten bath of said nickel sulfide from which copper has been eliminated, While avoiding side

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Description

Dec. 18, 1962 P. E. QUENEAU ETAL 3,069,254
AUTOGENOUS PYROMETALLURGICAL PRODUCTION OF NICKEL FROM SULFIDE CRES 2 Sheets-Sheet 1 Filed Aug. 23. 1960 PAUL E. QUENEAU LOUIS S. RENZONI INVENTOR C. (am
ATTORNEY Dec. 18, 1962 P. E. Qur-:Nl-:Au ETAL v 3,069,254
AUTOGENOUS PYROMETALLURGICAL PRODUCTION 0F NICKEL FROM SULFIDE ORES Filed Aug. 23, 1960 2 Sheets-Sheet 2 L.' coPPERRlcH J soLvENT l *,/44
l 3o I 43 \}7`J 30/ N i 43 I I NN U 39 x38 NICKEL L V suLFlDE @7 4 FIG. 3
PAUL E .QUENEAU LOUIS S. RENZONI INVENTOR.
ATTORNEY United States Patent ilice .3506952.54 t. AUTQGENOUS `PYR0MlE'IALLURGICAL PRODUC- M TIN F NICKEL FROM SULFIDE GRES Y p P'i'il Etienne Queneau, Fairfield, Conn., and Louis Secondo Ranzani, Copper CliiLOntarQCanad, s'sig'ito The International Nickel Company, Inc., New
York; N.-Y a corporation of Delaware p Filed' Ang.1 2s, 1960, ser. No. 51,438 1-2V Claims.` (014752-282) The pre-sent invention relates' to an" improved process for' the smelting` `and reii'ning of nickel- `and copper-containing sulfide materials for the direct recovery .of metallic nickel or nickel-copper y'alloys therefrom.
Attempts have been made yin the past to produce metallic nickel directly from nickel-containing matte. Thermodynamically and kinetically the react-ions between nickel suIlide, oxygen and nickel oxide in a converter allow full conversion of nickel mattei to metallic nickel. Although entirely feasible theoretically, an operable process based on-thesefreactionshas not heretofore been developed.
Borchers was perhaps the rst to attempt to blow nickel matte' to metal employing an oxygen blast, but because' of` lack oftemperature control and improper gasliquid-solid contact he was unsuccessful. We are familiar with the pioneer workof Lel'lep on the desulfurizing of nickel vmatte and' nickel-copper matte` to metallic nickel and nickel-copper alloys, respectively, by blowing in a converter. Lellep considered surface blowing in an elo'r't to solve .the insuperable problems which he encountered when employing submerged tuyere's at the high temperatures he was attempting-to use. Lellepdid not appreciate, however, the absolute necessity for ellicient gas-solidliquidcontact essential for bath' uniformity and achieve'- ment of equilibrium betweentheseveral reactants' and the overriding advantages of using oxygenor cxygenated air. yInstead he neglected the Vadvantages which are derived fromV mechanically' induced bath turbulence and he resorted .to preheatedV air or to extraneousheat fromA- oil, coalor electric energy, andiinally reliedV upon the' standard `Bes-semer` steel converter for .attempted application of his process. l Following the` failu-reof Lellep, Shottstall e-tl al. did further work onimproving the besseine'rizing of nickel-containing mattes to desulfuriz'e` such mattes. They attempted to` accomplish -this"byv forcing super-heated steam through .themolten' matteI employing submerged tuyerefs but their process was impractical. Shoistall` et al. valso fai-led to recognize the necessity of proper gas-liquid-fsolid contact and of' the advantages of usinga gasirich in oxygen relative to air.
The Bessemer converter isiernployedinithe'copper` in# dustry. to convert copper sulideto metalliccopper.n In' converting nickel-bearing'iron sulfide `in the m'oltenstate to low iron-nickel sullide, theartalso depends on the use' of` the Bessemer concept' involving` anV airblastbe-v low themolten matte level through tuyeres.V However, it-is impossible toA blown nickel sulde to metallic nickel in this manner. Forthis purpose thekairV must be-'highly preheated or oxygena-ted or fuel must'be Ialledto* maintain the required reactiomtemreratures. However, such modification of the-Bessemer principle isimpractical because of resulting. excessive localizedtemperature rise and4 refractory attackQ. inadequate gas-.solid-liquid cont'act' with resulting non-uniformity of the bath, fmassive, localized nickeloxide accumulations and inadequate control of op'eratingvariables. i
Althoughl Lellep', Shoffstall and' others madel attemptsl t-o overcome these"an'd other di'iiicul'ties, they were'un'- able to Ldevelop acommercially operable process. p
We have nowdiscovered'th-at sulfide' materials rich in nickel, suclriasores, concentrates and lmatter, may, after 3,069,254 Patented Dec;` 1,8,r 1962 preliminary preparation, if necessary, be successfully converted autogenously and directly to metallic nickel by the use of an oxygen-rich stream directed' onto' these materials, at least -a portion of which are; in the molten state" while providing efficient and effective gas-liquidsolid contact throughout the bath, Le., by induced turbulence and controlling oxygen supply and temperature. Furthermore, another critical deficiency in the prior'art which prevented continuous liquid phase production of metallic nickel was the inability to remove the copper which is normally associated with the sullide oresof nickel; We have also discovered that such copper may be continuously separated from nickel by a' major imiprovement in the obsolete and' abandoned Orford process.
It is an object of .the present invention to provide a process for the autogenous pyrometallurgica'l production of nickel or nickel-copper alloys from' nickel-copper sullide mattes. x
Another object of thetinvention is to provide a method fo'r producing metallic nickel directly from nickelfrich sulde materials such .as mattes by inducing turbulence of the liquid material and by impinging processt gases ont-he physically andcheriicallyV active surface thereof.
The invention also contemplates providing novel process for the direct reduction of substantially iron-free nickel matte's to nickel metal fanodes. n
lThe invention further contemplates providing` novel methods for separatingcopper and cobalt from low iron'- nickel mattes and for reducing `the nickel suhide directly to metallic nickel.v y
It is a further object of the .inventionA to provide' an autogenous method *for* eliminating rock, iron and sulfur from nickel'rich `sullide concentrates such as petlandite concentrates and obtaining nickel metalV low iii copper, cobalt and precious metals and .a sulfur dioxide-rich'gas suitable for economic sulfur fixation;
Other objects and advantages will become apparent yfrom 'the following description' taken' in' conjunction with the; accompanying' drawing in' which FIGUREV l .shows4 a. longitudinali section through' a". rotary kiln-typefurnace viny which the" autog'en-onsV smelt'-` ingf and desulfuriz'ing of` nickel=rich sulfide materials t metallic nickel according to the hereindes'crifbed' process may be: carried out;`
AVFIG., 2;,depicts a cross-section' of the saine" furnace through line 2 2 of' FIG. l; and' FIG. 3 shows'a'diagrammatic!cross-section through a liquid-liquid extraction column ili'which copper maybe separated from-nickelV sulfides by the special solventy extraction` process described hereinafter.'
yAccording to the presentir'ivention,"nickel-containing sulfide 'materials such as* nickelA matte andv crud nickel sulfide precipitatessuch as "those obtained by ore'wleachiig techniques are smelted autogenously in arotarykilriltyp furnace to a matte, This is'followed'bytop-blowi gth matte so obtained'in the same"autognous,"rotaryfkiln; type' furnace using commercial oxygen' or xygeii-eh-` riched air directed' down onto the surfaceofthe'nliolten bath butI not throughgthe metal frombelow' theliquid leveh By-'proper control of Voxygen supplyand'bathtem peratnre and by strong-mechanically-induced agitation of-the bathwthe molten nickel sulde is reduced ,to sub-V staritdially" sulfur-free nickel metal. The blowing' and mechanical agitation of the bath are controlled'each in` dependent of Athe other. Control `of oxygen ,supplyf and of turbulence is such las to maintain satisfactory' bath iluidity land uniformityA lto permit rapidj 4nickel sulfidenickel oxide reaction and high efficiency of oxygen utiliza. tionl while maintaining the' temperature below, that at whichundueirefractory attack isI experienced. Whenthe sulfur con'teiit has been decreased Ato" less thanabout 4%' and'at'which tiinsutlicient oxygen'is normally present in the bath to oxidize this sulfur, the blast is replaced by oxygen-impoverished gases, i.e., gases having an oxygen content insufficient to cause visible formation of interfering amounts of nickel oxide dross on the surface of the agitated bath. It is critically important that such gases be at such a high temperature as to permit bath temperature regulation in the 3000 F. to 3200 F. range. A-t the same time, strong mechanically-induced agitation is continued or increased in intensity to maintain eicient and effective gas-solid-liquid contact throughout the bath. The turbulence in the bath is mandatory to insure bath uniformity, both physical and chemical, so as to give quick reaction towards equilibrium, e.g., the nickel oxidenickel sulfide reaction. By this technique sulfur in the molten bath may be eliminated to less than about 0.05% sulfur, e.g., 0.01% sulfur. It will be understood of course, that alternatively standard desulfurization techniques can be employed for final sulfur removal.
Agitation of the bath to insure adequate gas-liquidsolid contact is obtained by rotating the furnace and by blowing the oxygen-rich gas stream onto the turbulent molten bath from above the liquid level. It has been found that the blowing operation may be conducted initially at temperatures not greatly above the melting point of the nickel sulfide-containing material and at this stage advantage is taken of the exothermic heat of reaction to smelt solid feed if desired. However, it is preferred to heat the nickel sulfide to a temperature of at least about 2400 F., avoiding formation of surface oxide, under weakly or non-oxidizing conditions prior to blowing with commercial oxygen. If no melting is to take place and molten matte at elevated temperature is available, proper rate and degree of heating can be achieved by control of oxygen addition. The temperature is raised as desulfurization proceeds until, at a sulfur content of the bath of less than 4%, advantageously between about 1% and about 3%, a temperature between about 3000 F., and 3200o F., is attained and maintained until final sulphur elimination is achieved. It will be understood that if the nickel contains a substantial proportion of copper, final ytemperatures will be significantly lower.
In carrying one embodiment of the invention into practice, nickel matte, which may contain less than about 1% iron, the amount of copper remaining after conventional separation of copper by ore dressing means, e.g., one part of copper to ten parts of nickel, and some cobalt and precious metals, e.g., one part of cobalt to 25 parts of nickel and 2 ounces of precious metals per ton of nickel, is treated, if desired, for the removal of the copper, cobalt and precious metals as hereinafter described. The matte is then transferred to the autogenous reduction furnace wherein it is top blown with oxygen to nickel metal.
The autogenous reduction operation may be carried out in the furnace depicted in FIG. l and FIG. 2 of the accompanying drawing which show a longitudinel section of the furnace and a cross-section of the furnace through line 2-2 of FIG. 1, respectively. Referring to FIGS. 1 and 2, the molten, nickel sulfidecontaining material is treated in a rotary kiln-type furnace 11 which is lined with high-grade refractory brick 12. The furnace may be tilted as desired for tapping by using tilting mechanism 20. The furnace has tires or drive rims 13 aixed circumferentally around it and these tires rest on supporting or drive wheels 14. Oxygen or oxygen-enriched air is supplied by a water-cooled tube or pipe 15 which projects through seal 21 and opening 16 into the furnace. Exhaust gases pass out of opening 17 at the other end of the furnace into the flue 18 which may be water-cooled and which may be swung away from the kiln opening to allow charging of fresh sulfide, flux or other materials through opening 17. Solids may be alternatively charged through opening 16 upon removal of pipe 15 and seal 21. Seal 22 provides a gas-tight contact between the kiln and ue 18. Slag may be withdrawn by tilting the furnace and tapping from the top of the molten bath. At the completion of the blow, molten metallic nickel is tapped by tilting the furnace into the position shown by 23 in FIG. 1 or is optionally withdrawn through taphole 19.
The reduction operation need not be conducted in the apparatus as specifically shown in FIG. 1 and described hereinbefore providing the apparatus meets the operational requirements as outlined herein, e.g., it may be carried out in a top blown converter such as the Kaldo furnace.
Based on tonnage tests, which we have conducted, we estimate that a single furnace of the above-described design, with effective inside diameter of about 17 feet, can produce commercial nickel at the rate of about 500 tons per day.
Nickel matte which is substantially iron-free may be blown directly to metallic nickel after copper removal, if necessary, from the molten material as described hereinafter. Precious metals may be removed as described hereinafter before blowing directly to metallic nickel.
The sulfide material which has been charged into the furnace is treated by bringing oxygen or oxygen-enriched air into direct contact with its surface. This gas, which advantageously is initially commercial oxygen, is blown into the furnace above the surface of the molten material. Necessary bath turbulence is maintained by continuous rotation of the furnace at a substantial speed.
In the first stage of the blow the temperature of the bath is kept high enough to keep the reacting materials in a sufficiently fluid state to permit rapid reaction and yet below the temperature at which undue refractory penetration or erosion is experienced. For relatively pure nickel matte which melts at about l450 F., the furnace blow may be started at a temperature of as low as 1550 F. However, in most circumstances it is preferred to initiate the blow with commercial oxygen at much higher temperatures than 1550" F., e.g., 2500 F., in order to avoid formation of nickel oxide slag and accretions. For sullides containing substantial amounts of iron as well as nickel, such as pentlandite concentrate, and which require considerable slagging off of iron, the temperature must be high enough to keep the slag in a fluid state.
It is important that substantially all iron is eliminated and any slag is removed from the furnace before blowing for sulfur removal to form metallic nickel is commenced. It has been found that any formation of slag during reduction of the nickel matte to metallic nickel results in serious decrease in gas-liquid contact and lowers oxygen efficiency. Thus, only by keeping the surface of the molten bath reasonably clear of slag is economic desulfurization in the autogenous reduction furnace possible.
As sulfur elimination of the bath by the top blowing with oxygen or oxygen-enriched air proceeds, the temperature of the bath is rapidly raised until the sulfur content of the bath has been lowered to preferably between about 1% and about 3% and a bath temperature of more than about 2800 F. has been attained. It has been found that the temperature of the reduction operation and, in fact, the operation in general is controlled by varying the oxygen supply, by observing exhaust gas analysis and temperature and by varying turbulence.
During this first stage of sulfur elimination down to between about 1% and about 3% sulfur, it is preferable to inject as much oxygen as is practicable without causing undue nickel oxide slag formation or too much splash formation at the mouth of the furnace. Use of commercial oxygen allows more rapid nickel reduction and production of gas rich in sulfur dioxide, e.g., 75% sulfur dioxide, but excess heat is also thereby generated. Part of this heat is utilized for heating the charge to the temperature desired for final sulfur elimination, i.e., between about 3000 F. and 3200 F. It may be desirable to cool by injecting air into the furnace. The addition of air may be, of course, undesirable in lowering the sulfur dioxide content in the exhaust gas and increasing the gas quantity required per unit volume of injected oxygen.,
Cooling may be otherwise accomplished or may be supplemented by adding water to the gas stream rather than air or by adding solid charge to 4the furnace or by a combination of these techniques.
When desulfurization has proceeded to preferably -between about 1% and about 3% sulfur, eg., 2% sulfur, the. oxidizing. gases. should be. replaced, as. aforestated, by substantially sulfur-free oxygen-impoverished gases, e.g., neutral or somewhat reducing gases while heating or maintaining the molten. bath to a temperature of between `about 3000 F. andV about 3,200o F. To maintain this temperature in the bath, the neutral or reducing gases must be at; a high temperature and this is best accomplished by adding aV highly combustible.` fuel such as natural gas on propane together with the oxygen. The fuel consumes any excess oxygen and generates a high temperature flame so that undue formation of nickel oxide isthereby` prevented.. Theimpinging gases may thus advantageouslyI and. gradually be decreased in. oxygen content from that of comercial. oxygen, to: oxygen-enriched f air., to air; to oxygen-impoverishment, to non-oxidizing or inert. and finally: to somewhat reducing. It will be understood that, once. adequate oxygen supply is present in the bath, the functionof the impinging gases. is heat supply and; insurance` of a low sulfur dioxide partial pressure atmosphere. The. exact oxygenI content of the. gas is` variable determined. by and` within the. control: of the furnace operator.; It has been: found that during this final desulfurization periodbest resultsV are obtained by. increasingbathturbulence; especially if for any reason the bath: hasV become over-oxidized:
By the above: noveltechnique', desulfurization of the lmolten' nickel' proceeds. to` less than 0:05.% sulfur, eigz, 0.01%y sulfur. Blowing'of molten nickeli sullidefmaterial down to these. lowgsulfur contents on at tonnage basis has been'foundto'be` attainable in less than 81hours.
FinaL desulfrization, which` isv carried. out. under al neutral'` or.V somewhat reducing atmosphere, is essentially achieved; by reaction. between residual sulfur.` and oxygen in the molten metal. Asurprisingly high. absorption'off oxygen takes placei in our-metal bath before any'visibleA oxide lm on its. Vsurface appears. Thus, inione case, arr apparent dissolved oxygen content of 9.5% was obtained while the metal was at a temperature of 3100o F., which is a much higher content-than-expected from study of the nickel-oxygen equilibrium diagram. We believe a substantial proportion of f this i oxygen wasy present as anA extremely nely-divided', uniformlyY dispersed, solid nickeli oxide. phase. Highoxygen. content in the sulfur-bearing bathy is aikeyt featurelofour turbulent metal desulfurizing process in4 that. it permits' elimination. of the: oxidizing: furnace.- atmosphere at amuclr` higher sulfur; contentiof' themetalbath than in'the prior art.. Theo xygenlcontent of the bath required for effective final desulfurization, of course, neednot` be as-high asthe above. Sulfur isyprefl erably, eliminatedlwithout formingwisible oxide floating; on the surface, `i.e., temperature and oxygen additionzis' so controlled as to maintain a shiny surface on the metal bath. Speed of rening increases the higher the oxygen content of the bath without surface oxide formation, e.g., without substantial clouding of the bath surface.
Asastatedhereinbefore, the surface `of the molten bath shouldbekept free of slag or scum. For this purpose the oxidizing gasesinthe furnaceA preferablyshould' be replaced by, nonfoxidi'zing gases before sulfur.. elimination; has proceeded tofbelwaboutl%-sulfur; e.g.^, 2% sulfur: Deoxidation ofsthe molten bathaftersulfur" removal may be readily carried out .by carbon addition to the furnace. Graphite has been foundto be an excellent deoxidizing agentcalthoughother: deoxidantsf such'asisilicon or'aluminum .mayl be utilized. A high residualIoxygencontentfin theibathl should; of course, be `avoided since'large quanti* ties oficostly deoxidizing` agents ,are requiredand` possiblyy violent; reactions may foccur;
In a modiied procedure for carrying out the reduction' of' nickel -sulde to metallic nickel by" our novel tech niques the final desulfur'izationvr from below 4% sulfur is` carried out in a separate furnace in the same manner' as described hereinbefore.y This modified procedure may be advantageous over doing` the complete operation in one furnace. Thus, lfinal refining' may' be carried out in a furnace the walls of which are' not impregnated with sulfide which has the: effect of delaying the lowering of -sulfur content in the bath and also presents a risk= of re-absorption, ifi deoxidation is carried out inside the furnace before tapping.V There is a further advantage in using a secondfurnace. in that brick which is not impregnated with sulfide' will allow increased refractory strengthl `at the; high temperature necessary during final desulfurization. Furthermore, the two furnaceI technique will allow steady' operation in one? furnace which is utilizing oxygen only and so attain an even. produc'- tion of gas with a. high sulfur dioxide content produced while usingf the second' furnace which isi utilizing oxygenimpoverished gases with. generally more rapid furnace rotation. Also;` any oxide formedr in theV first furnace could beeasily retained therein' for subsequent reaction with green charge, with the` final blow in the second furnace. being carried out without risk of slag. formation,`
It is to be noted that the herein described novel reduction of. nickelY -sulde to metallic nickel can be attained with very smalll nickellosses due either to slagging as oxide; or. to'dustingin exhaust gases, i.e.,` `a nickely yield' in excess of 99%. We have produced nickel by our process on a tonnage basis containingv 0.009% sulfur, 0.02%- silicon, 0.00-l7% lead, 0.000l% zinc 0\.0`004%l bismuth andl 0.0014.% antimony.
The extremeimportance and: necessity connected strong. induced turbulence of.r the furnace bath as described hereinbefore, is demonstrated. by the failure to obtain the desired results by blowing in `a stationary' furnace as shown in Example VII described hereinafter in which the nickel reduction reaction ceased" at a sulfur content of 2% in the bath due Ito excessive locali oxidationand resultant formation of' a floating impenetrable, hard, nickel. oxide blanket. A similar resultis obtained if attempts are made to. reduce the sulfur content of the bath to below about 1% sulfur before replacing the oxygen with high temperature,-weakly oxidizing, nonoxidizing, neutral and7or reducing gases which we have termed oxygenLii-npover-ished' gases and which have an oxygen content insufficient to cause` visible frmationof interfering amounts of nickel oxide' dross on the l surface ofV the f agitated bath, e'.g=, with ai free oxygen= content' of less than about 3%. In cases whereA iron-containingv nickel nlatteis-ii1'st'v blown in tliev autogenous reduction furnace'forironremoval, theslag formedV is treatedfon recovery of" its nickelE content. dvantageously, slagj produced during the first stage of iron eliminationwliicli is low in nickel i-s removed and treated for recovery of its nickel content, if desired)A and the slag produced duringrthefmal-stage.oflironeliminationisleft.in thecfumace. for. recovery of itsinicke'l content upon further addition of'l concentrate-tori matte.M After af complete charge of molten matte rhas-'been built up in the autogenous furnace, slag produced from final iron elimination is removed and Imay be. treatedV in parallel' autogenous reduction furnac'effor treatment with;v fresh sulfide.
In the `instances where nickel sulfide-materialsto b'eAL treated lby, this process contain `amounts offcopper or cobalt which may not be acceptable in the nickel metal, eag.,.. more than. a'bout.0."10!%iA copper fand/.or moreA than aboutl0.75% cobalt in thezimetal, the -sulfrdetmaterial must be .processed for"y their removal.
The copper advantageously should:;be removed before` desulfurizing. treatmentv in the top blowna: reduction furnace.l` Coppersremoval..byfmeans ofsa novelsolvent extraction process, ie., high temperature liquid-:liquid extraction, has been found particularly advantageous. By this technique we have found that nickel sulfide with a substantial copper content, e.g., a ratio of nickel:copper of, for instance, 10:1 can be treated for copper .removal to produce a nickel sulde having a residual copper content of less than 0.10%, e.g., with a ratio of nickelzcopper of at least about l000:1. As a general rule nickel sulfide ores containing copper can be concentrated by flotation so that the bulk of the nickel is in a concentrate containing nickel and copper in a ratio of at least about 10:1 which can be readily decopperized by our novel procedure. Much higher copper contents can be extracted by this method if simpler prior separation, eg., of the natural minerals by flotation, is impractical.
This novel molten salt solvent extraction technique is based on the use of sodium sulfide as the selective agent, probably a complexing agent, for copper sulfide. This agent is dissolved in molten sodium chloride in which solution nickel has only a slight solubility and copper a high solubility. An essential feature of this salt cornbination is its relatively low melting point of below about 1300 F. This permits the solvent extraction to proceed at a temperature as low as about 1350 F. Thus, the extraction is carried out close to the melting point of the metal sulfides which is the optimum temperature for liquid copper-nickel separation. This low operating temperature and the high water solubility of the extractant have the additional important advantages of economy in reagent, fuel and refractories consumption.
This novel separation technique is outstanding in that sequestration of copper by the solvent and isolation of nickel are both highly effective while the cost of labor, supplies and equipment is relatively low. Our procedure permits economical removal of co-pper sulfide, entirely beyond the capability of the existing art, from sulfides having a broad range of nickel to copper ratios to yield nickel sulfide having a nickel to copper ratio of greater than l000:1.
The highly beneficial effect of using a solvent, such as sodium chloride for sodium sulfide is clearly demonstrated by the following example:
EXAMPLE I 150 grams of matte, containing 68.2% nickel and 3.25% copper, was mixed with 150 grams of sodium sulde and the mixture was melted at 1550 F. The upper sodi-um-rich and the lower nickel-rich fractions were tapped from the bottom of the crucible into separate containers although there was found to be no sharp physical definition between them. Analyses of these upper and lower layers gave the results as shown in Table I.
The test was then repeated except that 75 grams of sodium chloride and 75 grams of sodium sulfide were used instead of 150 grams of sodium sulfide. Two distinct liquid fractions were obtained by this test which were cleanly separated by bottom tapping. The two fractions were then analyzed to give the results as shown in Table II.
8 Table II o Total Nickel Weight, percent Ni: Cu Ratio Percent Percent Cu Nl Upper Sodium-Rich Frac- In this novel liquid-liquid solvent extraction technique about one-half to double by weight of a mixture of sodium chloride and sodium sulfide may be melted with the copper-containing nickel sulfide material. The sodium chloride-sodium sulfide mixture advantageously may contain between about 25% and about 75% sodium chloride.
It will be understood that although we prefer sodium chloride, other chloride modifiers such as the chlorides of potassium, calcium and aluminum may be employed.
The nickel sulfide material and sodium salts are advantageously melted at not below about 1350 F. and not above about 1550 F., carefully mixed to insure excellent countercurrent liquid-liquid contact and then separated by gravity into copper-rich and nickel-rich fractions. A preferred apparatus for this purpose is a liquid-liquid extraction column as shown in FIGURE 3. The substantially copper-free nickel sulfide product may be air blown for slagging of residual sodium salts and then transferred directly to the autogenous reduction furnace to be blown to metallic nickel as described hereinbefore. The copper-sodium rich product may be treated by water leaching to recover copper and the sodium salts and residual nickel. Alternatively, the extraction may be carried out in other apparatus, e.g., in an appropriately designed, countercurrently operated rotating kiln or by simple ladle mixing, settling and bottom pouring in a countercurrent multi-stage operation. The advantageous results obtained by our novel solvent extraction technique rfor extracting copper from nickel sulde are shown in Examples II and III.
EXAMPLE II A nickel matte containing 3.25% copper with the bal- Analysis, Percent NizCu Ratio Cu Ni Final Copper-Rich Solvent--.. 4. 2U 1. 2 0.3:1 Final Nickel Sulfde 0.03 63. 3 2110:1
EXAMPLE III A nickel matte containing 4.8% copper with the balance mainly nickel and sulfur was treated for copper extraction in the same way as in Example II except that the countercurrent extraction was conducted at 1400 F. The final products from the four-stage treatment analyzed as follows:
Analysis, Percent NizCu Ratio Cu Nl Final Copper-Rich Solvent l 6.25 1.2 0.211 Final Nickel sulfide 0.06 i 63,3 l 105ml It has been found highly advantageous to use a continuous countercurrent solvent extraction technique to attain copper removal down toless than about 0.1% copper in the nickel sulde material. The countercurrent liquid-liquid extraction may takeplace in a standard type of apparatus such as that shown in FIGURE 3 which depicts. the diagrammatic cross-section of a baille plate column in which theV copper-containing nickel sultide is treated with themolten salt mixture for elimination of copper. Referring` to FIGURE 3, solid baffle plates. 30, which extendpartially across the colunmcrosssection, are placed at suitable intervals in the column. Molten copper-containing nickel sulfide from storage tank 31-` is introduced through line 32' and variable orifice 33 into the top ofthe column at 34. Molten sodium saltsolvent from storage tank 35 is introduced through line- 36 and: variable orice 3l'7` into` the bottom ofthe column at 3S. Nickel sulfide from whichl copper has been eliminated. is drawn olf the. bottom of the `column throughv line 39s and. variable orice 40. Copper-rich solventis drawn off-` the top ofthe column-through line 41. HeatY is. supplied tothe column and` to the tanks-31 and 35' tov maintain the sulde and sodium salts in a molten condition and at the separation temperature desired such as byway of electric immersion heaters 42 and external electric heaters 43;
The heavier nickel sulfide flows along eachbaille, which is. supplied with` a short lip 44 so that each is substantially a tray, overiiows over the lip and then flows downward tothe next tray; The lighter sodiumsalt solvent flows upwardV around each baille and throughthe free area between the tray and the inside wallsV of the column Thus, as the sodium saltsolvent rises throughthefalling nickel sulde andremoves copper sulfide it becomes progressivelyl richer in copper-sullide, while the n'ckel sulfide has more and more coppersulfide extractedvv as it flowsdownward.
A; mini-plant multi-tray column of the above generalv design, 3 inchesLD. by 4S` incheshigh was operated aty a feed rat-e of up to. one-half' ton per dayof copperbearingnickel4 suliideemploying as asolvent a salt4 mixture consisting. of sodiuml sulfide and sodium chloride and containing between 25%A and 75 sodium chloride. ln. thissimple device we were able to continuously-lower the copper content of the nickel matte in a ratio of about 110:1, producing: a nickell suldewith a Ni:CuA ratio exceedingV 1000:1when treating'mattes in the 0.75% Cu to. 3.5% copper range. The test results-vindicatedv that nickel' suldehaving a` substantially-higher copper content, e.g., 10% copper, could also be successfully treated.
Basedr on` equilibrium dataestablished for our novel,` liquidi-liquid extractionA system in the laboratory and fur,- therv substantiated by the above mini-plant experiments, copper reductions by weighty of 100:1 or more` can be realized from cupriferous nickel' sulfide when using our process` in commercial extraction equipment such as tray4 columns,- Packed` columns-.or mixer-settlers.
I-tis to b e observed that ournovel: technique for removing copperfrom nickel rn-attesi before blowing tometallinickel permits a much higher degree of copper.` elimination therefrom than can; be obtained; by controlled coolingt andullotation, of -thematte, ire., lessthan 0.05% Cuas comparedto morethan:y 0.50%
As. stated. hereinbefore` the. moltennickel matteY from.i which thecopper has advantageously-been ext-racteddownt to below about 0.310% coppermay-betransferredto theV autogenpus reduction; furnace, preferably after residuale sodium salts, have been removed by ra brief, relatively lowtemperature, airblow in a separate vessel and decantedr for reuse. However, in cases where there. are precious` metal valuesv associated with the. nickel suliide material the precious metals may be removed by known meansA such as by blowingpto create a sulfur deficiency, cooling, solidifying, grinding and removing the, precious` metals, concentrated in the metallics. The.` nickel sulfide, may then be, water leachedto. remove sodium salts, dried land then fed directlytov the autogenousl reduction kiln.
In speciall circumstances, cobalt elimination may be accomplished during 4conversion of the; sulfide, material to metal by blowing the molten material with an oxygenrich gas at a sulfur content off; more than about 3% to selectively oxidize the cobalt in the presence of a ilux such as silica. The cobaltr is then skimmed' off.' as slag. The sulfur content of the molten charge is maintained at above about 3% sulfur by continuously adding fresh sulfide material' to the autogenous reduction furnace while top-blowing at between about 2300-o F; and about2800 F24 for sulfur :and cobalt removal'. When the furnace has receivedV ia full charge and' adequate cobalt removal has been achieved, the top-blowing of" the molten charge is then completed as described hereinbefore to form metallic nickel; The cobalt-rich slag can be conveniently treated for cobalt recovery by known means. It will3 be understood', however,vthat formation ofthisslag can interfere with our process, as hereinbefore described, so that cobalt removalY in this manner is notv always practicable.
The following example illustrates the, satisfactory re;- sults that may be obtained by our technique for eliminating cobalty from nickel sulfide:
illustrative examples-are given:`
EKA-MELE V A suhideorecontaining nickel; copper, cobalt; ironand-gangueminerals was treated by conventional methods to produce a concentrate containing-12.0% nickel, 1.6%-
copper,4 0.4% cobalt, 40.0% iron, 311.0% sulfur and 7% silica. Thisconcentrate was autogenously smelted with oxygen to a matte containing 48.2%' nickel, 8.6% copper, 1.6% cobalt, 28% sulfurand the balance mainly iron.
l rFheslag from this operation-containing 115% nickel' was.
removedlfor separate treatment to recover its-metallvalues. rlibe-marte was then` blown with oxygen to produce a sub-V stantially` iron-free matte which was tapped: to leave a high nickel slag in--the` furnace-for subsequent reduction withfreshcharge. Thismatte was treated for copper removal 'at 1400- F. by our `solvent extraction technique as `describedlhereinbefore in Example III. Theresulting substantially ironandcopper-free matte wastreated toy remove cobalt by theprocess described in Example IV; The thus-treatedf matte wasV top blownwith oxygen atI a temperature--rising-to 2850` F. 'to a sulfur content of 32%'. The thus blown matte can then b e treated, as has been described above, forfinal sulfur elimination.
EXAMPLE VI 4:4` tonsof a` molten nickel matte containing. 70.9%v nickel, 4.8% copper, 1.0% iron and 23.3% sulfur were topblown with-,oxygen in a furnace, similar to that-shown in FIGURE l2, rotating at 20'r.p.m. at a temperature rising to 3000 F. Cooling was accomplished4 by itijecting air with the oxygen. The molten material was blown down to 1.4% sulfur at which point propane gas was injected with the oxygen and rotation of the furnace was increased to r.p.m. Enough propane was injected to produce a somewhat reducing atmosphere in the furnace. The temperature of the bath rose to and was held at about 3l00 F. and the molten bath was blown to a sulfur content of 0.02%. The bath at the end of the blow had an oxygen content of 1.9% which was removed by adding graphite to the bath in the furnace. Total blowing time to nal desulfurization was seven hours and fifty minutes.
EXAMPLE VII To illustrate the extreme importance of strong mechanically induced agitation of the molten bath during blowing, 4.3 tons of the same nickel matte as treated in Example VI were blown with oxygen in a manner similar to t-hat used in these examples except that the furnace remained stationary. After eight hours and forty minutes of blowing the sulfur content of the metal had been decreased to only 2%, further reaction ceased and blowing had to be discontinued because of nickel oxide accumulation with formation of a heavy impenetrable layer of slag floating on the metal. It -is to be observed that by the above described invention, metallic nickel can be produced directly from nickel concentrates obtained by flotation of nickel sulfide ores after copper removal by our novel techniques as described hereinbefore. It is known that pentlandite concentrate may be oxygen-flash smelted to a nickel matte, as disclosed by one of the present inventors in U.S. Patent No. 2,668,107. Our new process is an improvement over that described in this patent in that our product is metallic nickel instead of nickel matte with a high impurities content. Summarizing our technique for treating nickel concentrates by our novel process to obtain metallic nickel directly, we charge dry nickel concentrate, eg., pentlandite concentrate, into molten material in an autogenous reduction furnace, such as described hereinbefore, and blow for removal of iron which may be slagged off by addition of siliceous flux. The slag produced during the first stage of iron elimination, low in nickel, is removed from the furnace and the slag produced during the final stage of iron elimination is left in the furnace for extraction of its nickel content upon further addition of concentrate. After iron removal is completed, the molten material may be treated for copper removal and Iit is then blown directly to metallic nickel both of which operations are above described in detail.
It is further to be observed that the hereindescribed process is highly suitable for lthe treatment of crude mattes obtained from lateritic nickel-containing ores as for instance, by the process described by one of the present inventors in the copending U.S. patent application Serial No. 51,418, filed August 23, 1960, now U.S. Patent 3,004,846. These mattes which contain substantial amounts of iron and some cobalt can be blown in the autogenous reduction furnace for iron, sulfur and cobalt removal and direct production of metallic nickel. Since these lateritic ores normally contain substantially no copper Or precious metals, the molten material need not be treated for their removal but in the case of ores with a substantial cobalt content, the matte may be treated for cobalt removal as described herein.
It is to be observed also that prior art techniques for directly reducing nickel-rich matte to commercial metallic nickel or nickel-copper alloys failed utterly because of formation of metal oxides rather than metal with resultant massive accumulations of accretions and of floating dross which smothered the reaction long before it was complete and also because of destruction of refractories due to subsurface blowing of the bath and/or lack of proper bath turbulence with consequent excessive local temperature rise.
Furthermore, it is to be observed that our novel copper removal technique, by high temperature liquid-liquid separation is a major advance over the now long obsolete Orford process which was abandoned because of its high cost and the low separation efficiency of its batch-type operation.
This application is a continuation-in-part of our copending U.S. application Serial No. 839,431, filed September l1, 1959, now abandoned.
Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Thus, our process may be employed for the treatment of copper-rich materials, eg., copper flotation concentrates and mattes to yield directly fire-refined or anode copper. Such modifications and variations are considered to be within the purview and scope of the invention and appended clams.
We claim:
1. An improved process for autogenously converting a nickel sulfide material to produce nickel of low sulfur content which comprises directing oxidizing gases from the group consisting of commercial oxygen and oxygenenriched air into the exposed surface of a molten bath of said sulfide material, while avoiding sidewall and bottom blowing of said gases through the bath, and maintaining the bath during the converting in a state of turbulence with non-pneumatic, mechanically induced agitation, said agitation being maintained during the directing of said oxidizing gases, to promote intimate and efficient gas-liquid-solid contact and uniform distribution of oxygen throughout the bath and its rapid reaction with sulfur therein; raising the bath temperature as desulfurization proceeds to more than about 2800 F.; changing said gases being introduced into the bath surface to hot, substantially sulfur-free gases from the group consisting of neutral and reducing gases having an Oxygen content insufficient to cause visible formation of interfering amounts of nickel oxide dross on the surface of the bath when the sulfur content of the bath is still substantial but is less than about 4% and the oxygen content of the bath is at least sufiicient to oxidize the sulfur content, the bath being at a temperature of at least about 3000o F. and maintained in a turbulent state by non-pneumatic, induced agitation upon changing from oxygen-rich gases; and maintaining a bath temperature of at least about 3000 F. in the presence of said hot gases to continue the reaction between sulfur and oxygen in -the turbulent bath and to produce nickel with a sulfur content low enough below 0.5% for removal by desulfurization.
2. A process as described in claim 1 in which mechanically induced agitation of the molten Ibath is attained by rotation of the furnace and the metallic nickel obtained contains not more than about 0.02% sulfur.
3. An improved process for autogenously converting a nickel sulfide material to produce refined nickel. of low sulfur content which comprises blowing commercial oxygen onto the exposed surface of a molten bath of said sulfide material While avoiding sidewall and bottom blowing of said oxygen through the bath, and maintaining the bath substantially slag free during the blowing with oxygen and in a state of turbulence with mechanically induced agitation, said agitation being maintained during the blowing, to promote intimate and efficient gas-liquid-solid contact and uniform distribution of oxygen throughout the bath and its rapid reaction with sulfur therein and to produce off-gas rich in sulfur dioxide; raising the bath temperature as desulfurization proceeds to more than about 2800 F. whileV continuing said blowing with oxygen; transferring the bath to a substantially sulfide-free furnace environment when the sulfur content of said bath is still substantial but is less annessa 13;- thanl .about 4% and its oxygen content isr at least, suvfli-,A cient to oxidize. theY sulfur content; blowing onto said transferred bath, maintained` in e, state f turbulence by mechanically induced agitation, het gasesfiern. the grens consisting ef neutral and reducing gases substantially free 0f sulfur dicnide and having en Oxygen content in-V sntiicient tc. canse visible iennationA of. interfering einennts ci nickel Oxide dress en the surface 0f tbe betln tbe transferred. beth beine at n temneretnre. cf, at leest ebbnt 3Q0O l-s, maintaining a batn temperature ef at least about 3000 F; in the presence of said hot gases to continue the reaction between sulfur and oxygen in the turbulent beth end te Obtain rnetnllic. nickel; and, dcoxidizing the molten bath to produce refined, nickel' with a low sulfur content of not more than of; the order of about 0.05%.l
4. In a process for producing refined, metallic nickel fromv nickel-rich sulfide materials containing iron in which the sulfide materialV is smelted, to produce a nickeliron matte andthe nickel-iron matte is` blown to remove iron therefrom and form a nickel matte, the improvementW which comprises autogenously smelting the nickel matte by blowing commercial oxygen onto the exposed surface of a molten ba-th4 of said nickel matte at atemperature ofV at leastabout 2400 F., while avoidingsidewall and bottom blowing of said oxygen through the bath, and maintainingthe'bathv 4substantially free of slag during the blowing with oxygen and in a state of turbulence with mechanically induced agitation, said agitationJ being maintained during the blowing, to promote intimate and efficientl gas-liquid-solid contact and uniform distribution ofoxygen throughout the bath and its rapid reaction with sulfur therein; raising. the bathtemperaturel as desulfurization proceeds tomorethan about 2800 F; while continuing. said blowing with oxygen; changingsaid oxygen being directed onto the molten bath to hot gases from the group consisting of neutral and reducinggases substantially free of sulfur dioxiden and having. an oxygen content insufficient to cause visible formation of interfering amounts of nickel-z oxideA dross on the surface of the bath when its sulfur content` is between about 1% and -about 3%. `and its oxygen contentr is at least` sufficient to oxidize the sulfur content, the bath. being at. a temperature of'between about 3.0009 F; and' 3200"v F. and maintainedl in a turbulent state by, mechanically nducedagit-ation upon changing from oxygen; andi maintaining -a bath, temperature of between about 3000? F` and 3200? in the presence of'said hot gasesA to continue the reaction between sulfur and oxygen in the turbulent bathV and to, produce refined, pig nickel: with, a low sulfur content of; not more than ofv the order of` about 0.05%.
5. Ant autogenous process for producing refined metallic nickel directly from nickel-rich sulfide materials containing iron which comprises directing commercial, oxygenA onto the surface of'a molten bat-hof said nickel-rich sulfide material while avoiding sidewall and bottom blowing of said oxygen through the bath, said bath being maintained in a state ofturbulence by mechanically in duced agitation, saidagitation being maintained during the directing of" said oxygen, to oxidize iron` and. desulfurize the bath; slagging the `oxidized iron with silica flux and drawing off the slag so formed; raising the temperature of the molten bath after slagging of said iron and as desulfurization proceeds to attain a bath temperature of at least about 2800 F., While continuing the directing of oxygen onto the molten bath maintained in a state of induced turbulence to promote intimate and efficient gas-liquid-solid contact and uniform distribution of oxygen throughout the bath and its rapid reaction with sulfur therein; changing said oxygen being directed onto the molten bath to hot gases from the group consisting of neutral and reducing gases substantially free of sulfur dioxide and having an oxygen content insufficient to cause visible formation of interfering changing. said; gases. berng mtroduced; into the. bath, suramounts et nickel. @aide dross on the. surface.. of the bath, when itsY sulfur content is. between about, 1% and. ebent 3% and` its oxygen. cententiset least snicient te QXidize tbe snlfnr centent, the bathr being at temperature. of; et` leest nbent 300.0 1?- a nd maintained in e, turbulent state by yrnecli.en icnlr induced aaitatien nnen changing frein Oxygen; and, maintaining, n bntb temperaturev 0f at. least about'` 3000 E. in the presence of said hot gases to cmtinue the reaction between sulfur and oxygen in the turbulent bath and to produce refined, pig nickel with a low sulfur con-tent ofnot more than of the order o f about 0.05%.
6`- A process as `described in claim 5A in which the nickel-rich sulfide material contains cobaltl and wherein, after iron is oxidized, slagged and drawn off, the sulfur content ofthe metal bat-h is maintained at greater than about 3% by adding fresh sulfide material while blowing with oxygen at between about 2 300 F. andl about- 2800" F.` to oxidize the cobalt and remove it as slag.
7i. An improved process for- -au-togenously converting a nickel-copper sulfide material to produce nickelecopperalloy of "low sulfur content which comprises directingoxygen-rich gases from the group consisting of commercial` oxygen and oxygen-enrichedair into the. exposed sur-face tof-V a moltenf bath of said sulfide material, while avoiding sidewall and` bottom blowing ofsaid gasesA through the bath, and maintaining the. bath during the converting. in a state of turbulence. with non-pneumatic, mechanically induced4 agitation, said agitation being maintained during the, directing of said oxygen-.nich gases, to, promote intimate and efficient gas-.liquid-sc lidl contact and uniform distribution of'A oxygen throughout therbath, 4and its rapid reactions with sulfur therein; raising the, bath temperature as desulfurization proceeds while` main-V. taining its surface substantially -free ofoxide dross;
face to4 hot, substantially sulfur-.free gases` from the. group consisting off neutral and. reducing gases havinganoxygen content-insuliicientf to cause visible formation, of; interfering amounts1 of nickel; oxide dross on the` surfaceA of the bath whenl its, sulfur; content ist still substantial but is less; than` about,V 4% andI itsf oxygen con-l tent is. at.- least sufficient. to oxidize the, sulfur cen-tent, the bath being.` maintained ina tnrbnlentzstate by nen-` nnenrnatie. induced: asitatien'nndf at a bien temeer-attire sntiicient, te; minimize. tbeterrnatien et. oxide dress en tbe surface-,i nf: the; nieleelnepree alley. beth. nnen, c bensfL ing frein Oxygen-cicli; gases; and; maintaining the bien temperature in tbe, beth. in tbe. presence. ciy said bet ariseste. centinne tbe reaction between sulfur; and. Oxygen. in. thetnrbnlent; beth and te, Produce nickel-copper.- aller with, al sulfur.. content loWl uQllgh below 0.5,% for re-A moval; b y. desulfurizatiorn.
8, An Aimproved process, for eliminating` copper. from` and autogenously, smelting, a n iclel sulfide. material containingcbpertovnr-ednce refined, nignickel ci lewfsnlinr content which comprises` melting and mixing between abcnt ene-half tedenble-by weishtei a; mixture ct sedinrn chloride, and, sodiumv sulfide. salt-s with; said nickel sulfide materiel-in the ineltenI state; allowing said melten innss` seperate ntog en upper center-richand` sodium salt-` containing liquid phase. and a lower nickel` sulfide liquid pbase; sernratina seid liquid nbasesz. trentina said' Unger liquidphase forrecovery of the sodium salts contained therein; oxidizing and removing sodium salts from the lower, nickel sulfide liquid phase; directing 4oxygen onto the exposed surface of la molten bath of said nickel sulfide phase, while avoiding sidewall and bottom blowing of said oxygen through the bath, and maintaining the bath `during the smelting in a state of turbulence with mechanically induced agitation, said agitation being maintained during the directing of 4said oxygen, to promote intimate and eiiicient gas-liquid-solid contact and uniform distribution of oxygen throughout the bath and its rapid reaction with sulfur therein; raising the bath temperature as desulfurization proceeds to more than about 2800 F. while continuing the directing of oxygen onto the bath; changing said oxygen being directed onto the molten bath to hot gases from the group consisting of neutral and reducing gases substantially free of sulfur dioxide and having an oxygen content insufficient to cause visible formation of interfering amounts of nickel oxide dross on the surface of the bath when its sulfur content is between about 1% and about 3% and its oxygen content is at least sufiicient to oxidize the sulfur content, the bath being at a temperature of at least about 3000u F. and maintained in a turbulent state by mechanically induced agitation upon said changing from oxygen; and maintaining a bath temperature of at least about 3000 F. in the presence of said hot gases to continue the reaction between sulfur and oxygen in the turbulent bath and to produce refined, pig nickel with a low sulfur content of not more than of the order of about 0.05%.
9. In the treatment of a nickel sulfide material with a copper content of at least about 0.50% for elimination of the copper and recovery of the nickel contained therein, the improvement which comprises melting and mixing between about one-half to double by weight of a salt mixture of sodium sulfide and a metal chloride from the group consisting of sodium chloride, potassium chloride, calcium chloride and aluminum chloride with said nickel sulfide material inthe molten state; allowing said molten mass to separate into an upper copper sulfide-salt mixture liquid phase and a lower nickel sulfide liquid phase; separating said liquid phases; treating said upper liquid phase for recovery of the salt mixture contained therein; oxidizing and removing salt mixture from the lower, nickel sulfide liquid phase; and treating said nickel sulfide liquid phase for recovery of the nickel contained therein.
10. A process as described in claim 9 in which the salt mixture is sodium chloride and sodium sulfide and contains between about 25% and about 75% sodium chloride, the separation of the copper sulfide-salt mixture phase and the nickel sulfide phase is carried out in a liquidliquid extraction column and the nickel sulfide phase separated out contains less than 0.10% copper.
ll. In the treatment of a nickel sulfide material with a copper content of at least about 0.50% for elimination of the copper and recovery of the nickel contained therein, the improvement which comprises melting and mixing between about one-half to double by weight of a mixture of sodium chloride and sodium sulfide salts containing between about 25 and about 75% sodium chloride with said nickel sulfide material in the molten state at a temperature of not below about 1350" F. and not above about 1550 F.; allowing said molten mass to separate into an upper copper sulfide and sodium salt-containing liquid phase and a lower nickel sulfide liquid phase with a copper content of less than about 0.10%; separating said upper and lower phases by pouring one from the other in the liquid state; treating said upper liquid phase for recovery of the sodium salts contained therein; reverting said sodium salts for further copper elimination; oxidizing and removing any sodium salts from the lower, nickel sulfide liquid phase; and treating the nickel sulfide remaining for recovery of the nickel contained therein.
12. In the treatment of cobalt-containing nickel sulfide material with a copper content of at least about 0.50% for elimination of the copper and cobalt and recovery of the nickel contained therein as refined, pig nickel of low sulfur content, the improvement which comprises melting and mixing between about one-half to double by weight of a salt mixture of sodium sulfide and a metal chloride from the group consisting of the chlorides of sodium, potassium, calcium and aluminum with said nickel sulfide material in the molten state; allowing said molten mass to separate into an upper copper sulfidesalt mixture liquid phase and a lower nickel sulfide liquid phase; repeating the foregoing operations in a countercurrent manner; separating the final liquid phases; treating the upper liquid phase for recovery of the copper and the salt mixture contained therein; oxidizing and removing salt mixture from the final, lower, nickel sulfide liquid phase; directing commercial oxygen onto the exposed surface of a molten bath of said nickel sulfide from which copper has been eliminated, While avoiding sidewall and bottom blowing of said oxygen through the bath, and maintaining the bath in a state of turbulence by mechanically induced agitation, said agitation being maintained during the directing of said oxygen, to promote intimate and efficient gas-liquid-solid contact and uniform distribution of oxygen throughout the bath and its rapid reaction with sulfur therein; maintaining the sulfur content of the molten bath at more than about 3% by adding substantially copper-free fresh nickel sulfide material, while blowing with oxygen at between about 2300 F. and about 2800 F. to oxidize the cobalt and remove it as slag; raising the temperature of the molten bath when cobalt has been eliminated and slagged off and as desulfurization proceeds to more than about 2800 F. while continuing the directing of oxygen onto the bath; changing said oxygen being directed onto the molten bath to hot gases from the group consisting of neutral and reducing gases substantially free of sulphur dioxide and having an oxygen content insufiicient to cause visible formation of interfering amounts of nickel oxide dross on the surface of the bath when its sulfur content is still substantial but is less than about 4% and its oxygen content is at least sufficient to oxidize the sulfur content, the bath being at a temperature of between about 3000 F. and 3200 F. and maintained in a turbulent state by mechanically induced agitation upon said changing from oxygen; and maintaining a bath temperature of between about 3000" F. and 3200 F. in the presence of said hot gases to continue the reaction between sulfur and oxygen in the turbulent bath and to produce refined, pig nickel with a low sulfur content of not more than of the order of about 0.05%.
References Cited in the file of this patent UNITED STATES PATENTS 1,599,424 Lellep Sept. 14, 1926 `1,623,797 Lellep Apr. 5, 1927 .1,703,329 Wilenchik Feb. 26, 1929 1,877,928 McGregor Sept. 20, 1932 2,396,792 Kroll Mar. 19, 1946 2,598,393 Kalling et al May 27, 1952 2,653,868 Lichty Sept. 29, 1953

Claims (1)

1. AN IMPROVED PROCESS FOR AUTOGENOUSLY CONVERTING A NICKEL SULFIDE MATERIAL TO PRODUCE NICKEL OF LOW SULFUR CONTENT WHICH COMPRISES DIRECTING OXIDIZING GASES FROM THE GROUP CONSISTING OF COMMERCIAL OXYGEN AND OXYGENENRICHED AIR INTO THE EXPOSED SURFACE OF A MOLTEN BATH OF SAID SULFIDE MATERIAL, WHILE AVOIDING SIDEWALL AND BOTTOM BLOWING OF SAID GASES THROUGH THE BATH, AND MAINTAINING THE BATH DURING THE CONVERTING IN A STATE OF TURBULENCE WITH NON-PNEUMATIC, MECHANICALLY INDUCED AGITATION, SAID AGITATION BEING MAINTAINED DURING THE DIRECTING OF SAID OXIDIZING GASES, TO PROMOTE INTIMATE AND EFFICIENT GAS-LIQUID-SOLID CONTACT AND UNIFORM DISTRIBUTION OF OXYGEN THROUGHOUT THE BATH AND ITS RAPID REACTION WITH SULFUR THEREIN; RAISING THE BATH TEMPERATURE AS DESULFURIZATION PROCEEDS TO MORE THAN ABOUT 2800*F., CHANGING SAID GASES BEING INTRODUCED INTO THE BATH SURFACE TO HOT, SUBSTANTIALLY SULFUR-FREE GASES FROM THE GROUP CONSISTING OF NEUTRAL AND REDUCING GASES HAVING AN OXYGEN CONTENT INSUFFICIENT TO CAUSE VISIBLE FORMATION OF INTERFERING AMOUNTS OF NICKEL OXIDE DROSS ON THE SURFACE OF THE BATH WHEN THE SULFUR CONTENT OF THE BATH IS STILL SUBSTANTIAL BUT IS LESS THAN ABOUT 4% AND THE OXYGEN
US51438A 1959-09-11 1960-08-23 Autogenous pyrometallurgical production of nickel from sulfide ores Expired - Lifetime US3069254A (en)

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US51438A US3069254A (en) 1960-08-23 1960-08-23 Autogenous pyrometallurgical production of nickel from sulfide ores
FR838143A FR1274967A (en) 1959-09-11 1960-09-08 Autogenous pyrometallurgical production process of nickel from sulphide ore
DEJ21254A DE1139981B (en) 1959-09-11 1960-09-12 Process for separating nickel and copper
GB31367/60A GB960698A (en) 1959-09-11 1960-09-12 Improvements relating to the production of nickel from sulphide ores
GB31368/60A GB960699A (en) 1959-09-11 1960-09-12 Improvements relating to the separation of copper from nickel
NL6412531A NL6412531A (en) 1959-09-11 1964-10-28

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Cited By (9)

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US3272616A (en) * 1963-12-30 1966-09-13 Int Nickel Co Method for recovering nickel from oxide ores
US3468629A (en) * 1965-03-12 1969-09-23 Int Nickel Co Recovery of nickel from nickel-containing sulfide materials
US3516818A (en) * 1967-04-26 1970-06-23 Int Nickel Co Fire refining of nickel-containing metallurgical intermediates and scrap
US4045215A (en) * 1973-07-16 1977-08-30 Creusot-Loire Method of refining mattes containing nickel
US4244733A (en) * 1977-08-19 1981-01-13 Boliden Aktiebolag Method of producing blister copper from copper raw material containing antimony
US5074910A (en) * 1987-11-23 1991-12-24 Chevron Research And Technology Company Process for recovering precious metals from sulfide ores
US5104445A (en) * 1987-07-31 1992-04-14 Chevron Research & Technology Co. Process for recovering metals from refractory ores
US6270554B1 (en) 2000-03-14 2001-08-07 Inco Limited Continuous nickel matte converter for production of low iron containing nickel-rich matte with improved cobalt recovery
RU2205243C2 (en) * 2001-08-22 2003-05-27 Шехтер Леонид Натанович Method for producing metal alloy from copper-nickel sulfide melt

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US1599424A (en) * 1923-04-07 1926-09-14 Int Nickel Co Refining nickel matte and nickel-copper matte
US1623797A (en) * 1926-07-07 1927-04-05 Int Nickel Co Method of converting nickel-containing matte
US1703329A (en) * 1928-04-16 1929-02-26 Israel W Wilenchik Process for separating copper from nickel
US1877928A (en) * 1930-07-25 1932-09-20 Mcgregor Alexander Grant Smelting of metallic ores, particularly copper sulphide ores
US2396792A (en) * 1944-03-22 1946-03-19 William J Kroll Refining nickel
US2598393A (en) * 1948-10-25 1952-05-27 Kalling Bo Michael Sture Method in carrying out treatment of melted pig iron or other alloyed iron
US2653868A (en) * 1950-10-30 1953-09-29 Northfield Mines Inc Recovery of metals from metallurgical slag

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US1599424A (en) * 1923-04-07 1926-09-14 Int Nickel Co Refining nickel matte and nickel-copper matte
US1623797A (en) * 1926-07-07 1927-04-05 Int Nickel Co Method of converting nickel-containing matte
US1703329A (en) * 1928-04-16 1929-02-26 Israel W Wilenchik Process for separating copper from nickel
US1877928A (en) * 1930-07-25 1932-09-20 Mcgregor Alexander Grant Smelting of metallic ores, particularly copper sulphide ores
US2396792A (en) * 1944-03-22 1946-03-19 William J Kroll Refining nickel
US2598393A (en) * 1948-10-25 1952-05-27 Kalling Bo Michael Sture Method in carrying out treatment of melted pig iron or other alloyed iron
US2653868A (en) * 1950-10-30 1953-09-29 Northfield Mines Inc Recovery of metals from metallurgical slag

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3272616A (en) * 1963-12-30 1966-09-13 Int Nickel Co Method for recovering nickel from oxide ores
US3468629A (en) * 1965-03-12 1969-09-23 Int Nickel Co Recovery of nickel from nickel-containing sulfide materials
DE1533277B1 (en) * 1965-03-12 1970-11-19 Internat Nickel Company Of Can Process for the production of nickel carbonyl
US3516818A (en) * 1967-04-26 1970-06-23 Int Nickel Co Fire refining of nickel-containing metallurgical intermediates and scrap
US4045215A (en) * 1973-07-16 1977-08-30 Creusot-Loire Method of refining mattes containing nickel
US4244733A (en) * 1977-08-19 1981-01-13 Boliden Aktiebolag Method of producing blister copper from copper raw material containing antimony
US5104445A (en) * 1987-07-31 1992-04-14 Chevron Research & Technology Co. Process for recovering metals from refractory ores
US5074910A (en) * 1987-11-23 1991-12-24 Chevron Research And Technology Company Process for recovering precious metals from sulfide ores
US6270554B1 (en) 2000-03-14 2001-08-07 Inco Limited Continuous nickel matte converter for production of low iron containing nickel-rich matte with improved cobalt recovery
RU2205243C2 (en) * 2001-08-22 2003-05-27 Шехтер Леонид Натанович Method for producing metal alloy from copper-nickel sulfide melt

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