RU2245377C2 - Method for reprocessing of sulfide concentrate with high content of pyrrotine - Google Patents

Abstract

FIELD: autoclave hydrometallurgy, in particular hydrometallurgical reprocessing sulfide concentrates.

SUBSTANCE: method for reprocessing of sulfide concentrates with high content of pyrrotine includes blending of raw concentrate with mineral stabilizing additive; autoclave oxidative leaching of produced mixture in aqueous pulp under oxygen pressure at temperature above the sulfur melting temperature in presence of surfactant to convert non-iron metals into solution, sulfur - to elementary form, iron - to oxides; deposition of non-iron metal sulfides from oxidized pulp solution followed by recovery of non-iron metal sulfides and elementary sulfur by flotation into multiple sulfur-sulfide concentrate and iron oxides into rock refuse. Alkali or alkali-earth compounds with aluminum silicate are used as stabilizing additive, added at mass ratio of pyrrotine to total silica and alumina content of 1:(0.05-0.33) and mass ratio of copper to pyrrotine <1:55; or at mass ratio of pyrrotine to total silica and alumina content of 1:(0.5-0.8) and mass ratio of copper to pyrrotine 1:55 or more. Pyrrolitine decomposition ratio is at least 95 %, and leaching yield of sulfide mass is not less than during treatment of common pyrrotine concentrate.

EFFECT: improved method for reprocessing of sulfide concentrates.

9 cl, 1 tbl, 4 ex

Description

The invention relates to the field of autoclave hydrometallurgy, in particular to methods of hydrometallurgical processing of sulfide concentrates characterized by a high content of pyrrhotite, with the oxidation of sulfide sulfur to an elemental state, and can be used in combined processes for the enrichment of various high-sulfur pyrrhotite products, including high-temperature oxidation of pyrrhotite to produce a product, containing elemental sulfur.

A known method of processing “ordinary” (low sulfur) pyrrhotite concentrates containing up to 2.5% nickel, not more than 0.5% copper and ~ 66-68% pyrrhotite, including autoclave oxidative leaching of the concentrate with the conversion of sulfur to elemental, non-ferrous metals into solution and iron to oxides at temperatures above the melting point of sulfur in the presence of surfactants - industrial lignosulfonates, the deposition of non-ferrous metal sulfides from a solution of oxidized pulp, followed by their separation and elemental sulfur by flotation in a sulfur sulfide concentrate, and jelly oxides and - in the final tailings. The main sulfide-forming mineral, pyrrhotite, contained in “ordinary” pyrrhotite concentrates, is represented by more than 70% hexagonal easy-opening structural modification (Fe ₁₁ S ₁₂ ). This method was industrially implemented at the Nadezhda Metallurgical Plant in Norilsk (Smirnov II, Shivrin G.N., Sirkis A.L. Autoclave technology for processing pyrrhotite concentrate. - Krasnoyarsk: Publishing House of Krasnoyarsk Univ., 1986. - 256 p.).

The disadvantage of this method is that the "ordinary" pyrrhotite concentrate is isolated according to the scheme for the enrichment of sulfide copper-nickel ores, in which the resulting nickel concentrate contains a significant amount of pyrrhotite (~ up to 65%). The pyrometallurgical processing of such a concentrate is accompanied by increased losses of non-ferrous metals with waste slag and significant emissions of sulfur dioxide into the air basin. In particular, the ore-dressing and metallurgical complex of the city of Norilsk, processing copper-nickel pyrrhotite-containing ores using technology with the separation of "ordinary" pyrrhotite concentrates (-67-70% pyrrhotite), releases more than 2 million tons of sulfur dioxide into the atmosphere per year. According to the balance, approximately 75% of sulfur dioxide formed during the pyrometallurgical processing of copper and nickel concentrates is contained in “weak” gases (conc. SO ₂ from 0.5 to 1.5%), the direct processing of which for sulfuric acid and other chemical products by traditional methods technically difficult and economically impractical. Feasibility studies show that the environmental problem of reducing gaseous sulfur emissions to a limiting level, in the framework of the known method, is essentially insoluble, since it requires huge investment costs.

Another disadvantage of this method is that the processing of the entire mass of allocated pyrrhotite concentrate by autoclave-oxidation technology is associated with tremendous capital and operating costs, limiting the possibility of dynamically increasing the production of non-ferrous and precious metals from solid pyrrhotite ores.

A known method of processing sulfide concentrates with a high content of pyrrhotite (more than 68%). The known method includes autoclave oxidative leaching of a starting concentrate in an aqueous pulp under oxygen pressure in the presence of a surfactant with the conversion of non-ferrous metals into a solution, sulfur into elemental, iron into oxides, the deposition of non-ferrous sulfides from a solution of oxidized pulp, followed by the separation of non-ferrous sulfides and elemental sulfur by flotation in a collective sulfur-sulfide concentrate, and iron oxides in dump tailings (a study of the mechanism of kinetic features leached nickel-pyrrhotite concentrates: Research report / Institute “Gipronickel.” - Topic 3-91-074 vol. - No. GR 0191.0020296. — St. Petersburg, 1991. - 67 pp.).

Sulfide concentrates with a high content of pyrrhotite, the so-called high-sulfur pyrrhotite concentrates (MIC) and nickel-pyrrhotite concentrates (NPK), are formed at the stage of enrichment of solid sulfide copper-nickel ores according to the scheme, which simultaneously includes the separation and storage of low-nickel (≤ 1% Ni ) pyrrhotite. Isolation and storage of low-nickel pyrrhotite can significantly reduce the flow of sulfur and iron into the metallurgical cycle. This ensures high overall efficiency of the processing of pyrrhotite-containing ore, including drastically reducing sulfur dioxide emissions, which makes it possible to normalize the environmental situation of industrial metallurgical regions with bringing harmful emissions into air and water basins to environmental standards.

High-sulfur sulfide concentrates (VPK and NPK), obtained in various versions of the schemes for the enrichment of the initial pyrrhotite ores, in composition and properties significantly differ from the "ordinary" pyrrhotite concentrate, which is currently processed by the autoclave-oxidation technology. Their main difference lies in the high content of minerals of the pyrrhotite group with a simultaneously low content of waste rock minerals. Along with this, in high-sulfur NPK there is a significant amount of non-ferrous metals, including 3.5-4.0% nickel and up to 2.2% copper, the proportion of monoclinic pyrrhotite, which is difficult to open during leaching, in the NPK is significantly higher than in the "ordinary" pyrrhotite concentrate (Report of Gipronickel Institute. - No. GR 0191.00200296. - St. Petersburg, 1991. - 67 pp .; AI Stekhin Ecological and geological typification and evaluation of rich copper-nickel ores when controlling the quality of mineral raw materials : Abstract of thesis for the degree of Candidate of Technical Sciences. - M., 1992. - 16 p.; Technological tool share of the hydrometallurgical shop of the Nadezhda Metallurgical Plant - Reg. No. 0401.14.109-11-15-83. - Introduction date 01.01.84. - P.45).

A disadvantage of the known method is that when elemental sulfur is accumulated in the autoclave, sulfide concentrates with a high content of pyrrhotite tend to granulate. In particular, during the processing of MICs and, especially, high-sulfur NPKs containing more than 70-72% pyrrhotite and a significant amount of copper minerals, sulfur sulfide aggregates (granules, "sands") are formed in the autoclave during high-temperature leaching, which are prone to avalanche-like uncontrolled enlargement. In more “light” cases, this can greatly deteriorate the kinetics of the leaching process, since the screening of the sulfide surface with a molten sulfur film prevents the oxidizing agent from entering the reaction zone and inhibits the process (Borbat V.F., Leshch I.Yu. New processes in the metallurgy of nickel and cobalt . - M.: Metallurgy, 1976. - S.69-77). In more “severe” cases, the process stops completely due to the formation of a continuous “sulfur” sulfide melt in the autoclave (Investigation of the mechanism and kinetic features of leaching of nickel-pyrrhotite concentrates: Research report (stage) / Gipronickel Institute. No. ГР 0191.00200296. - St. Petersburg, 1991 .-- 67 p.). The tendency of the material to uncontrolled granulation deprives the known method of practical prospects in relation to the processing of sulfide concentrates with a high content of pyrrhotite.

A known method of processing NPKs, including autoclave oxidative leaching of a concentrate under oxygen pressure at a temperature above the melting point of sulfur in the presence of a surfactant, followed by precipitation of non-ferrous metals from a solution of oxidized pulp and separation of components by flotation, in which to prevent the formation of sulfur sulfide aggregates (sand, granules in autoclaves) ) the initial concentrate for oxidative leaching is served together with a mineral stabilizing additive - pulp of finely ground lime tnyaka (AP Makarov Intensification of autoclave-decanter technology for the processing of nickel-pyrrhotite concentrates: Diss for the degree of Candidate of Technical Sciences - L., 1987. - 261 s / DSP /....).

Limestone is an effective stabilizer of sulfuric emulsions, however, its use in the process of autoclave-oxidative leaching of sulfide concentrates is irrational due to the hard neutralizing effect. The addition of limestone for leaching increases the alkalinity of the treated pulp, which causes inhibition of the leaching of sulfides (Borbat V.F., Leshch I.Yu. New processes in the metallurgy of nickel and cobalt. - M .: Metallurgy, 1976. - 360). It is also known that the supply of a solid neutralizer (limestone, lime, etc.) to leach NPK creates local areas with a decrease in the acidity of the medium to pH 6-7. The consequence of this is the formation of non-floated amorphous compounds (carbonates, hydrates, basic salts), leading to an increase in the loss of non-ferrous metals with dump tailings of the autoclave technology. In another well-known work, it was shown that leaching of ferrosulfide materials at pH greater than 3 is characterized by the formation of finely dispersed, usually amorphous iron deposits, which precipitate on the surface of sulfides and further reduce the quality of the target product. (Schneerson Ya.M., Filippov GF, Borbat VF Behavior of rock-forming minerals during autoclave oxidative leaching of pyrrhotite concentrates // MTsM SSSR. TsNIITSVETMET ECONOMICS and INFORMATION / Series: Production of heavy non-ferrous metals. - M., 1980 . - 57 p.). In addition, limestone in some areas, for example, in Norilsk, is quite scarce, and its extraction and pulp preparation are associated with significant capital and energy costs.

A known group of methods for processing high-sulfur nickel-pyrrhotite concentrates, including operations of high-temperature leaching of the initial concentrate, deposition of non-ferrous metals and sulfur-sulfide flotation, in which a solid mineral additive is introduced into the NPK, which prevents sulfur coalescence and formation of sulfur-sulfide aggregates during leaching. As a mineral additive, chemically neutral rock-containing and technogenic (synthetic) non-metallic components are used: calcium sulfate dihydrate (gypsum), the hydrated phase of oxidized pulp from leaching of NPK (Research Report of Gipronickel Institute. - No. ГР 0191.0020296. - С.-- Petersburg. 1991. - 67 pp.) And finely ground natural anhydrite (Schneerson Ya.M., Filippov GF, Borbat V.F. Behavior of rock-forming minerals during autoclave oxidative leaching of pyrrhotite concentrates. - M., 1980. - 57 p.). Of these additives, only the iron-hydrate product, introduced in an amount of 15% by weight of the NPK, avoids the formation of sulfosulfide aggregates during leaching of concentrates that differ in the initial low (about 5%) content of gangue. Gypsum and anhydrite at a 15% flow rate provide only a partial decrease in the yield of granules, but are not able to completely eliminate their formation. An increase in the consumption of calcium sulfate stabilizing additives is economically unjustified, since it is associated with a significant increase in the costs of their extraction, transportation and grinding.

The use of a finely dispersed iron-hydrate product as an emulsifying mineral additive increases the mass of oxide iron in the feed of sulfur-sulfide flotation, which complicates the separation of sulfur-sulfide particles from non-metallic components, affects the quality of flotation products and reduces the target recovery of non-ferrous metals and sulfur. A disadvantage of the known methods is also the fact that in the processing of high-honey NPK (mass ratio Fe / Cu <25) all of the above mineral additives, incl. and iron-hydrate product at a flow rate of up to 30% by weight of the initial concentrate, do not protect the leaching process from the formation of sulfur-sulfide granules (Research Report of Gipronickel Institute. - No. GR 0191.0020296. - St. Petersburg. 1991 - 67 p.).

A known method of processing sulfide polymetallic pyrrhotite-containing materials (including high-sulfur pyrrhotite and nickel-pyrrhotite concentrates), including high-temperature autoclave-oxidative leaching of the material, the deposition of non-ferrous metals and sulfur-sulfide flotation. In the known method, in the process of oxidative leaching, along with a surfactant that prevents wetting of sulfides by molten sulfur, a mineral additive is introduced that stabilizes the sulfur emulsion and thereby prevents the aggregation of sulfur to form granules. Compounds containing calcium and sulfur, in which sulfur is represented by an intermediate valency form — thiosulfate, sulfites, polythionates, and other inorganic thiocalcium salts — are used as a mineral stabilizing additive (RF Patent No. 2016102 with prior dated January 4, 1992. Method for processing sulfide polymetallic pyrrhotite-containing materials. Publish. July 15, 94 in Bull. No. 13).

The disadvantage of this method is that all thiocalcium compounds with an intermediate valence of sulfur are expensive and scarce. The use of mineral-containing production effluents in which these compounds are present as by-products of sulfur redistribution (for example, the discharge of sulfur redistribution at the Nadezhda Metallurgical Plant of the Norilsk MMC) is complicated by a wide range of changes in the salt composition of effluents. In addition, production effluents have a relatively low concentration of thiocalcium salts (<30–40 g / dm ³ ), which is why capital-intensive construction of large tanks is required to ensure stable operation of the autoclave redistribution.

Another disadvantage of the known method is that the stabilization of the sulfuric emulsion in this method is achieved by oxidizing the sulfur in the mineral additive to the sulfate form with the conversion of thiocalcium compounds to semi-aquatic gypsum. The latter, having intermediate wettability, forms a structural-mechanical barrier at the sulfur – water interface, sharply reducing the number of effective collisions of liquid sulfur droplets. Stabilization of sulfuric emulsions by this mechanism leads to a negative side effect - excessive sludging of sulfur, which significantly complicates the process of subsequent autoclave smelting of sulfur and reduces the quality of sulfide concentrate.

The disadvantage of this method, in addition, is the relatively low degree of stabilization effect in the processing of high-honey NPK, especially with a high copper content.

The closest to the proposed method for the totality of the characteristics and the achieved result is a method for processing high-sulfur nickel-pyrrhotite concentrates, which includes introducing a mineral stabilizing additive into the initial concentrate, autoclave oxidative leaching of the resulting mixture in an aqueous pulp under oxygen pressure at a temperature above the melting point of sulfur in the presence of a surfactant with the transfer of non-ferrous metals to solution, sulfur to elemental, iron to oxides, followed by processing of oxidized pulp according to the schemes e, providing for the deposition of non-ferrous metals and collective sulfur-sulfide flotation. In the known method as a mineral stabilizing additive using “ordinary” pyrrhotite concentrate with a high content of gangue (Abramov NP Development of the technology of autoclave-oxidative leaching of high-sulfur nickel-pyrrhotite concentrate // Non-ferrous metals. - 1992. - No. 7. - C .9-13) - PROTOTYPE.

The disadvantage of the prototype is that the addition of high-sulfur NPK even a significant amount of "ordinary" pyrrhotite concentrate with a high content of gangue does not protect the oxidative leaching from the formation of sulfur sulfide granules and melt. This drawback is especially pronounced when processing NPK with a high content of copper minerals. The formation of sulfur sulfide aggregates during leaching of such materials is not prevented when they are diluted with a pyrrhotite-containing rock up to the level of “ordinary” pyrrhotite concentrates. It is characteristic that the qualitatively-quantitative patterns of stabilization of sulfuric emulsions established for the leaching process of “ordinary” pyrrhotite feedstock differ significantly from similar patterns of the process of leaching of NPK. In particular, the leaching of high-copper NPDs diluted with “ordinary” pyrrhotite concentrate to a rock content in the resulting mixture at a level of 11–13% at a mass ratio of (CaO + MgO) / SiO ₂ ≅ 0.4–0.5 passes with the formation of a sulfosulfide melt whose yield is ~ 33%. At the same time, as a result of the occlusion of mineral particles with liquid sulfur, there is a sharp inhibition of the sulfide oxidation process. According to well-known sources for 4 hours of leaching of NPK according to the prototype method, the degree of decomposition of pyrrhotite does not exceed 85% (Abramov NP // Non-ferrous metals. - No. 7. - 1992. - C.11). At the same time, it is well known and confirmed by a large body of experimental data that the complete suppression of sulfur aggregation during high-temperature leaching of “ordinary” pyrrhotite concentrates is achieved while two conditions are met: the mass content of the rock in the concentrate is at least 4-6% and the ratio in the rock (CaO + MgO) / SiO ₂ not less than 0.3 (Onatskaya A.A., Shneerson Ya.M., Mitenkov G.A. Influence of the composition of pyrrhotite concentrates on the behavior of liquid sulfur during autoclave oxidative leaching // Non-ferrous metals. - No. 2. - 1992. - S. 31-33).

The low efficiency of the "ordinary" pyrrhotite concentrate shown in the prototype method for stabilizing sulfuric emulsion during the leaching of high-sulfur NPK is apparently due to the mutual deactivation of the components of this stabilizing additive, which caused the opposite synergistic effect. In particular, autoclave pyrrhotite decomposes with the formation of iron hydroxides and elemental sulfur. Iron hydroxides, depending on the shape and dispersion, are capable of stabilizing sulfur emulsions in water to one degree or another. The finest stabilizing effect is exerted by highly dispersed iron hydroxides with a developed reaction surface (Goryachkin V.I., Nelen I.M., Shneerson Y.M. Hydrometallurgical processing of copper-nickel pyrrhotite concentrates based on autoclave oxidative leaching // Hydrometallurgy, autoclave leaching). , sorption, extraction. - M .: Nauka, 1976. - p. 53-54). At the same time, individual components of the rock contained in the "ordinary" pyrrhotite concentrate (Na ⁺ , K ⁺ ) bind iron ions to large-crystalline complexes - jarosite, thereby reducing the stabilizing activity of the formed iron-hydrate precipitate. On the other hand, these sediments adsorb on themselves the products of decomposition of waste minerals (gypsum, anhydrite, aluminosilicates, etc.), which cease to work as solid emulsifiers - stabilizers of molten sulfur. And, finally, additional amounts of elemental sulfur formed during the inherent oxidation of the "ordinary" pyrrhotite concentrate significantly enhance the effect of granule formation, suppressing the stabilizing effect of the hydroxide-rock components formed with the introduction of this stabilizing additive.

Another disadvantage of the prototype is that the use of “ordinary” rock-containing pyrrhotite concentrate as a mineral stabilizing additive to the NPK introduces additional iron and sulfur into the metallurgical production cycle. In particular, the consumption of “ordinary” pyrrhotite concentrate, providing a sulfur content in the mixture at the level of 30%, is ~ 200% of the weight of the NPK. This significantly reduces the efficiency of the ore processing method as a whole, since it limits the mass of low-nickel pyrrhotite removed for storage.

In addition, the disadvantage of this method is that the re-aggregation of elemental sulfur in the process of leaching of the NPC causes an overspending of the metallized precipitant in the deposition of non-ferrous metals and leads to the appearance in the pulp of serosulfide aggregates of non-floated particle size classes. The latter is the reason for the increase in losses of non-ferrous, precious metals and sulfur with dump tailings of sulfur-sulfide flotation and a decrease in the quality of sulfur-sulfide concentrate.

The problem solved by the invention is to develop a method for processing sulfide concentrates with a high content of pyrrhotite, which with any composition of concentrates completely eliminates the formation of sulfur-sulfide aggregates (granules, floats) during autoclave-oxidative leaching, and also provides a sufficient degree of decomposition of pyrrhotite (not less than 95 %) when the leaching rate for sulfide mass is not lower than when processing “ordinary” pyrrhotite concentrate.

The problem is solved in that in the known method of processing sulfide concentrates with a high content of pyrrhotite, which includes introducing a mineral stabilizing additive into the initial concentrate, autoclave oxidative leaching of the resulting mixture in an aqueous pulp under oxygen pressure at a temperature above the melting point of sulfur in the presence of a surfactant with the transfer of non-ferrous metals to a solution, sulfur to elemental, iron to oxides, the deposition of non-ferrous sulfides from a solution of oxidized pulp with subsequent separation of non-ferrous metal sulfides and elemental sulfur by flotation in a collective sulfur-sulfide concentrate, and iron oxides in dump tailings, according to the invention, as a mineral stabilizing additive introduced into the initial sulfide concentrate with a high content of pyrrhotite, alkali and / or alkaline earth metal compounds with a complex aluminosilicon compound are used radical (aluminosilicates) added in an amount that provides a mass ratio of pyrrhotite to the sum of silicon dioxide and alumina yuminium in the resulting mixture 1: (0.05-0.33) when the mass ratio of copper to pyrrhotite is less than 1:55, or providing a mass ratio of pyrrhotite to the sum of silicon dioxide and aluminum oxide in the resulting mixture 1: (0.5-0, 8) when the mass ratio of copper to pyrrhotite is more than or equal to 1:55.

Another difference of the method is the use of rock-forming aluminosilicates as a mineral stabilizing additive in the composition of ore-bearing rocks.

The next difference of the method is the use as ore-bearing rock containing aluminosilicates, final and intermediate products of the enrichment of sulfide ores.

Another difference of the method lies in the fact that the tailings of the concentration of sulfide copper-nickel ores are used as the final beneficiation products.

The next difference of the method is the use as the end products of the enrichment product of the gravitational separation of rock tailings enrichment of sulfide copper-Nickel ores, concentrating aluminosilicates.

Another difference is that natural zeolites are used as aluminosilicates.

Another difference of the method is the use of synthetic zeolites as aluminosilicates.

Another difference of the method is that aluminosilicates are used as a mineral stabilizing additive in the composition of metamorphic rocks of the contact halo of intrusions.

Another difference of the method is that aluminosilicates are used as a mineral stabilizing additive in the composition of intrusive rocks.

In the process of creating the invention, it was found that the use of aluminosilicates as a mineral stabilizing additive in the autoclave-oxidative leaching of sulfide concentrates with a high content of pyrrhotite (MIC and NPK) can completely stop the aggregation of sulfur, significantly accelerate the oxidation of sulfides and provide a high degree of decomposition of pyrrhotite. Moreover, the proposed mineral stabilizing additive performs several functions at once:

- Disperses molten sulfur and stabilizes its emulsion in the treated pulp.

- Deactivate copper minerals that increase the tendency of the oxidized material to granulate.

- Improves the structure and rheological characteristics of iron hydrate precipitates formed during autoclave-oxidative leaching of pyrrhotite concentrates.

- Significantly increases the flotation activity of the sulfur-sulfide phase formed in the leaching of the initial concentrate and the deposition of non-ferrous metals, improving the conditions for its separation from the iron-hydrate precipitate.

An unexpected and yet unexplained fact was that the well-known rock-forming additives recommended for suppressing granulation during autoclave-oxidative leaching of "ordinary" pyrrhotite concentrates turned out to be ineffective with concentrates with a high pyrrhotite content (more than 75%). At the same time, the proposed class of additives - aluminosilicates - and technical products containing them showed a high positive effect on the leaching of MIC and high-sulfur NPK, whereas according to the data of well-known literature, when leaching "ordinary" pyrrhotite concentrates, the use of aluminosilicates gives the opposite effect - it enhances the propensity of the material to granule formation. In particular, the authors of the work (Onatskaya A.A., Shneerson Ya.M., Mitenkov G.A. // Non-ferrous metals. - 1982. - No. 2. - p.31-33) based on the conducted research it was shown that, in order to avoid the enlargement of sulfur particles during autoclave-oxidative leaching of "ordinary" pyrrhotite concentrates, carried out at elevated temperatures using surfactants, the concentrate should contain at least 4-6% of the rock. Moreover, the ratio (CaO + MgO) / SiO ₂ in the rock, called the criterion of its emulsifying-stabilizing effect, should be at least 0.3. It is emphasized that when the indicated ratio of components in the rock is less than 0.3, it does not prevent granulation. Therefore, in the case of prevalence in the rock part of “ordinary” pyrrhotite concentrates of silica or biotite-feldspar hornfelsh (with a low value of alkaline module), it is recommended that the necessary ratio of oxides (> 0.3) be maintained by attaching to the initial concentrate calcium-containing components - gypsum, anhydrite, limestone and etc.

Studies conducted as part of the development of the present invention have shown that in relation to sulfide concentrates with a high content of pyrrhotite, especially high-sulfur NPK, rock-containing products with a high ratio of (CaO + MgO) / SiO _{2 are the} least preferred. For example, magnesian skarns and intrusive rocks with a high magnesium content (gabbrodolerite) have the indicated oxide ratio of ~ 0.6-0.8. These rocks contain significant amounts of easily opened magnesium silicates (olivines, serpentine), which neutralize acid during autoclave-oxidative leaching and thus inhibit the initial stage of the process. In addition, it was experimentally established that magnesium silicates do not inhibit the process of granule formation during the leaching of MIC and high-sulfur NPK even at costs up to 60% by weight of the initial concentrate. It was also established that:

- Intrusive rocks with a high Mg / Ca content and a modulus value of (CaO + MgO) / SiO ₂ > 0.3 not only do not provide granite suppression during leaching of MIC and high-sulfur NPK, but also as a result of inhibition of the initial stage of leaching, increase color losses and platinum metals with tailings of sulfur-sulfide flotation.

- Ore-bearing rocks with a high Al ₂ O ₃ / SiO ₂ ratio and low MgO / (Al ₂ O ₃ + SiO ₂ ) modulus are most effective as a mineral stabilizing additive.

- Calcium silicates with a high modulus of CaO / SiO ₂ have a stabilizing effect, preventing the formation of sulfur sulfide granules and melt. At the same time, they cannot be recommended as a mineral stabilizing additive due to sharp alkaline inhibition of the autoclave-oxidative leaching process and an increase in the loss of valuable components with tailings technology.

- All known aluminosilicates, regardless of their crystal-chemical structure, are effective mineral stabilizing additives.

- For practical purposes, it is preferable to use metamorphic rocks of a contact aureole of intrusions represented by quartz and silica-alumina hornfelses as a mineral stabilizing additive in autoclave-oxidative leaching of MIC and high-sulfur NPK. In the composition of the mineral associations composing these rocks, the main share (45-55%) are plagioclases and orthoclase.

The results obtained, which correspond to the processing of sulfide concentrates with a high content of pyrrhotite, are directly opposite to the recommendations from the literature regarding the processing of “ordinary” pyrrhotite concentrates with a relatively low content of pyrrhotite and copper minerals.

Another unexpected positive aspect associated with the addition of aluminosilicates to the leaching of high-sulfur NPKs was a regular increase in the completeness of the extraction of the main metals of the platinum group (platinum, palladium and rhodium) in the sulfide concentrate, which also disagrees with the well-known ideas about the effect of silicon dioxide on the formation of loss non-ferrous and platinum metals with tailings of sulfur-sulfide flotation.

An analysis of known methods for processing high-sulfur NPK shows that, unlike “ordinary” pyrrhotite concentrates, the presence of a high concentration of calcium sulfate in the oxidized pulp does not inhibit the process of granulation. A positive result is also not achieved by diluting the pulp with an inert substance (for example, highly dispersed iron hydrates). Both variants of stabilization of sulfuric emulsions do not allow eliminating the demulsifying (“seed”) effect of the increased content of copper minerals.

Suppression of the process of sulfur aggregation in the case of the addition of aluminosilicates to the high-sulfur NPK occurs, apparently, by the mechanism of deactivation of the “seed”.

It can be assumed that silicic acid formed during the decomposition of rock-forming minerals is adsorbed on the surface of copper sulfides, creating gel-like serophobic coatings that prevent wetting of copper minerals with liquid sulfur. Thus, the addition of rock-forming minerals capable of deep decomposition with the release of highly dispersed silicic acid and the weakening of the catalytic effect of copper minerals on the process of sulfur coalescence to a high-copper NPD is possible to achieve the required dispersion of oxidized pulp in a wide range of changes in the composition of the feedstock.

According to the experiment, the optimal consumption of aluminosilicates is determined by their composition, the content of pyrrhotite in the MIC and NPK and the ratio of copper to pyrrhotite. The last factor characterizes the ratio of the mass of the elemental sulfur formed (since pyrrhotite is its main source) and the mass of the copper “seed”, ie, it is essentially a criterion for the potential tendency of the material to granulate. It is preferable that the mineral stabilizing additive has a minimum iron and sulfur content, as well as a possibly lower ratio of basic rock-forming oxides (CaO, MgO) to acidic (SiO ₂ , Al ₂ O ₃ ). The latter is due to the fact that, with an increased consumption of aluminosilicates corresponding to the processing regime of high-honey NPKs, the main oxides neutralize the formed acid, which results in inhibition of the process. The introduction of a mineral stabilizing additive into the military-industrial complex and high-sulfur mineral-oil complex increases the gross weight of the material that is processed by the autoclave-oxidation technology. However, the intensification of the leaching process, due to the positive influence of aluminosilicates, allows you to keep the productivity of the technology for processing the mass in the resulting mixture no lower than when processing the “ordinary” pyrrhotite concentrate. The emulsifying and stabilizing effect of the proposed mineral additive, limiting the intensity of coalescence of sulfur droplets, enhances the effectiveness of the hydrocarbon surfactant used in leaching. This reduces its consumption, which provides an improvement in the performance of subsequent redistribution of autoclave technology.

The use of sulfide copper-nickel ore dressing waste products as a mineral additive can reduce the irrevocable losses of non-ferrous and precious metals that accompany the processing of sulfide polymetallic ores. This allows you to partially compensate for the loss of valuable components due to the storage of low-nickel pyrrhotite concentrate.

It was experimentally established that the boundary value of the ratio of copper to pyrrhotite in sulfide concentrates, at which there is a sharp change in the tendency of the material to granulate, is ~ 1: 55. Below this value lies the region of relatively “soft” (low-copper) concentrates. In this area, complete granule suppression during the leaching of VPA and VPA is achieved by the addition of aluminosilicates, which provides a mass ratio of pyrrhotite to the sum of silicon dioxide and aluminum oxide in the resulting mixture from 1: 0.05 to 1: 0.33. Outside this range, the results of using the method are sharply reduced: with a ratio of more than 1: 0.05 (less than 0.05 parts of SiO ₂ + Al ₂ O ₃ ), there is a tendency to increase sulfur, the probability of formation of a “goat” in autoclaves increases significantly, and the degree of decomposition pyrrhotite (up to values less than 85%); a decrease in this ratio to below 1: 0.33 (more than 0.33 parts of SiO ₂ + Al ₂ O ₃ ) is not economically feasible, since it does not improve the processing of the concentrate, thereby causing unproductive expenses for transportation and processing of sulfide raw materials that are excessively diluted with the rock . In the processing of high-copper sulfide concentrates (mass ratio of copper to pyrrhotite ≥ 1:55), the optimal ratio of pyrrhotite to the total (SiO ₂ + Al ₂ O ₃ ) in the resulting mixture is from 1: 0.5 to 1: 0.8. Outside this range, on the one hand, the process of granule formation is sharply activated (with a ratio of more than 1: 0.5; i.e., with less than 0.5 parts of SiO ₂ + Al ₂ O ₃ ), on the other hand, an “alkaline” ”Inhibition of the sulfide oxidation process and there is a high dilution of the material by the rock (with a ratio of less than 1: 0.8; that is, with more than 0.8 parts of SiO ₂ + Al ₂ O ₃ ).

The method is as follows.

In the initial sulfide concentrate with a high content of pyrrhotite released during the concentration of sulfide polymetallic pyrrhotite-containing ore, a mineral stabilizing additive is introduced. The amount of added additive is determined by the composition of the starting concentrate: when obtaining low-copper concentrates in which the mass ratio of copper to pyrrhotite is less than 1:55, the mineral stabilizing additive is introduced in an amount that provides the mass ratio of pyrrhotite to the sum of silicon dioxide and aluminum oxide in the resulting mixture 1: (0 05-0.33); upon receipt of high-copper concentrates (mass ratio of copper to pyrrhotite ≥ 1:55), the amount of mineral stabilizing additive introduced ensures the mass ratio of pyrrhotite to the sum of silicon dioxide and aluminum oxide in the resulting mixture 1: (0.5-0.8). As a mineral stabilizing additive introduced into the initial sulfide concentrate, compounds of alkali and / or alkaline earth metals with a complex alumina-oxygen radical (aluminosilicates) are used. In this case, rock-forming silicates can be used as part of ore-bearing rocks, as well as natural and synthetic zeolites. Ore-bearing rocks used as a mineral stabilizing additive can be represented, in particular, by metamorphic rocks of a contact halo of intrusions and / or intrusive rocks. It is most expedient to introduce aluminosilicates into the initial sulfide concentrate in the composition of the final and intermediate products of sulfide ore beneficiation, in particular, in the compositional tailings of sulfide copper-nickel ore beneficiation, for example: flotation tailings of solid sulfide pyrrhotite and cubanite-pyrrhotine, normally disseminated, richly - disseminated and cuprous copper-nickel ores, as well as dump tailings of a light fraction of the ore dressing process in a heavy suspension. Carriers of aluminosilicates used as a mineral stabilizing additive are also products of gravitational separation of rock tailings for the enrichment of sulfide copper-nickel ores, concentrating aluminosilicates.

The resulting mixture in the form of an aqueous pulp is subjected to autoclave oxidative leaching under oxygen pressure at a temperature above the melting point of sulfur in the presence of a surfactant, for example, technical lignosulfonates. After leaching is completed, the pulp is cooled to 95 ° C and precipitation from a solution of non-ferrous metals is carried out. Known sulfidizing reagents can be used for precipitation: metallized iron pellets, calcium sulfide, polysulfide-thiosulfate solutions. After the deposition of non-ferrous metals, the oxidized pulp is subjected to collective flotation to separate sulfosulfide particles from iron oxides and gangue components.

The efficiency of processing sulfide concentrate is estimated by the granulometric composition of oxidized pulp, the degree of decomposition of pyrrhotite, the chemical composition of the resulting flotation products, and the value of losses of valuable components with tails. Efficiency is higher, the lower the content of particles of the class +150 μm in the oxidized pulp, the greater the degree of decomposition of pyrrhotite, the less nickel and platinum metals pass into the flotation tailings, and also the lower the content of iron oxides in the foam product - sulfur sulfide concentrate.

The proposed method is described in specific examples, and its results are shown in the table.

In the experiments, we used a sample of high-sulfur nickel-pyrrhotite concentrate obtained at the Talnakhsky concentrating plant of the Norilsk Nickel Mineral Processing Plant OJSC. This concentrate is a product of flotation concentration technology for continuous sulfide copper-nickel pyrrhotite-containing ores, including the separation of low-nickel-rich pyrrhotite and directing highly concentrated pyrrhotite and directing NPK intended for processing by autoclave-oxidation technology. The average sample of high-sulfur NPK characterized the following composition,%: nickel - 4.26; copper - 1.15; cobalt - 0.21; iron - 53.8% sulfur - 36.4; pyrrhotite - 79.8; rock-forming - 3.48; in t hours: SiO ₂ - 1.82; CaO - 0.63; MgO - 0.25; Al ₂ O ₃ - 0.78. Coarseness of the concentrate - 82.4% of the class minus 44 microns; mass ratio of copper to pyrrhotite - 1: 69.4; mass ratio of pyrrhotite to the sum of silica and alumina -1: 0.033.

To simulate high-copper concentrates, the copper concentrate (MK) of the Talnakh enrichment plant, composition,%, nickel was added to the initial NPK in various ratios,%: nickel - 1.61; copper - 25.6; cobalt - 0.54; iron - 37.2; sulfur - 35.1; rock-forming - 1.47, including: SiO ₂ - 0.49; CaO - 0.55; MgO - 0.24; Al ₂ O ₃ - 0.19.

As a mineral stabilizing additive to high-sulfur NPK used:

1. Monomineral samples of five aluminosilicates with a purity of at least 95%. The samples studied were characteristic representatives of all known subclasses of aluminosilicates, differing in the nature of the combination of silicon-oxygen tetrahedra, including: island, ring, chain, layered, frame. The following monomineral fractions of aluminosilicates (AS) were tested:

- Vesuvian - Ca ₁₉ Mg ₃ Al ₁₀ [Si ₂ O ₇ ] ₄ · [SiO ₄ ] ₁₀ O ₂ (OH) ₆ - from a subclass of island AS (hereinafter referred to as WZV).

- Cordierite - Mg ₂ Al ₃ [AlSi ₅ O ₁₈ ] - from a subclass of ring AS (hereinafter - KRD).

- Augite - Ca ₂ MgFeAlSi ₃ O ₁₂ (a mineral of the pyroxene group) - from a subclass of chain AS (hereinafter referred to as AWG).

- Muscovite - KaAl ₂ [AlSi ₃ O ₁₀ ] (OH) ₂ - from a subclass of layered AS (hereinafter referred to as MSC).

- Plagioclase is a mineral from the group of feldspars belonging to the subclass of wireframe AS. This is a continuous isomorphic series of sodium-calcium aluminosilicates: albite - Na [AlSi ₃ O ₈ ] and anorthite - Ca [Al ₂ Si ₂ O ₈ ] (hereinafter referred to as PLG).

2. A sample of the metamorphic rock of the contact halo of the Talnakh intrusion, represented by a quartz horn (hereinafter - KR).

Mineral composition:

- melilit - chemical. composition: (Ca, Na) ₂ (Mg, Al) [(Si, Al) ₂ O ₇ ] - 3%.

- sillimanite: Al [AlSiO ₅ ] - 10%.

- cordierite: Mg ₂ Al ₃ [AlSi ₅ O ₁₈ ] - 20%.

- plagioclase: Na [AlSi ₃ O ₈ ] - Ca [Al ₂ Si ₂ O ₈ ] - 55%,

Chemical composition:

55.1% SiO ₂ ; 7.3% Fe _total ; 19.7% Al ₂ O ₃ ; 2.2% CaO; 5.6% MgO; 1.09% K; 6.1% Na.

3. An intrusive rock sample represented by contact gabbro-dolerite (hereinafter referred to as QGD).

Mineral composition:

- plagioclase - 50%;

- pyroxenes general structural formula:

R $\genfrac{}{}{0ex}{}{\text{2+}}{\text{2}}$ [Si ₂ O ₆ ], where R = Ca ²⁺ , Mg ²⁺ , Fe ²⁺ , Na ⁺ - 30%;

- biotite - K (Mg, Fe _2-3 ) [AlSi ₃ O ₁₀ ] (OH, F) ₂ - 15%;

- serpentine - Mg ₆ [Si ₄ O ₁₀ ] (OH) ₈ - 3%.

Chemical composition:

51.7% SiO ₂ ; 9.8% Fe; 17.3% Al ₂ O ₃ ; 9.3% CaO; 6.5% MgO; 1.7% Na; 0.05% K.

4. Silica-alumina cornea (hereinafter referred to as RAG).

Mineral composition:

- Plagioclase - 10%;

- Orthoclase - K [AlSi ₃ O ₈ ] - 35%;

- Biotite - K (Mg, Fe _2-3 ) [AlSi ₃ O ₁₀ ] (OH, F) ₂ - 40%;

- Chlorite - (Mg, Fe ²⁺ ) · [AlSi ₃ O ₁₀ (OH ₂ )] · 3 (Mg, Fe) (OH) ₂ - 10%.

Chemical composition:

54.7% SiO ₂ ; 7.2% Fe _total ; 20.5% Al ₂ O ₃ ; 2.5% CaO; 5.9% MgO; 0.958% Na; 6.1% K.

5. Specific tailings of flotation concentration of sulfide copper-nickel ores of Talnakh concentration plant (hereinafter referred to as HF).

Mineral composition:

- Plagioclase - 60%;

- Pyroxenes-15%;

- Olivin - 5% - (Mg, Fe) ₂ [SiO ₄ ];

- Quartz - 6% - SiO ₂ ;

- Garnets - 3% - (Mg, Ca, Fe) ₃ Al ₂ (SiO ₄ ) ₃ ;

- Calcite - 2% - (CaCO ₃ );

- Anhydrite - 4% (CaSO ₄ ).

Chemical composition:

0.29% Ni; 0.09% Cu; 14.01% Fe; 2.42% S; 47.2% SiO ₂ ; 7.29% CaO; 3.60% MgO; 13.1% Al ₂ O ₃ .

6. An intermediate product of the enrichment of sulfide copper-nickel ores in the Talnakhsky processing plant, which is a hydrocyclone discharge of a mixture of 2 products: material from a storage pond and sludge from a crushing and screening department (hereinafter referred to as PPO).

Mineral composition:

- Plagioclase - 45%;

- Sulphides - 28%;

- Pyroxenes - 5%;

- Olivin - 3%;

- Quartz - 2%;

- Magnetite - 10.0%.

Chemical composition:

1.36% Ni; 1.22% Cu; 26.51% Fe; 13.12% S; 34.5% SiO ₂ ; 5.32% CaO; 2.63% MgO; 12.2% Al ₂ O ₃ .

7. Natural aluminosilicates from the zeolite group (monofractions pure ~ 95%)

- Analcime - Na (AlSi ₂ O ₆ ) · H ₂ O (hereinafter - ANL).

- Chabazite - Ca ₂ (Al ₄ Si ₈ O ₂₄ ) · 13H ₂ O (hereinafter referred to as SCB).

- Nosean - Na ₈ [AlSiO ₄ ] ₆ SO ₄ (hereinafter - NZN).

8. Synthetic zeolites:

- Zeolite H-K ₂ O · Al ₂ O ₃ · 2SiO ₂ · 4H ₂ O hereinafter referred to as (CN).

- Zeolite X - Na ₂ O · Al ₂ O ₃ · 2.5SiO ₂ · 6H ₂ O (hereinafter referred to as CH).

Example 1 (experiment 1 of the table) - implementation of the analogue method

In this experiment, the autoclave-oxidative leaching of high-sulfur NPK was carried out without introducing a mineral stabilizing additive into the concentrate. The experiment was carried out in a laboratory autoclave with a capacity of 1 DM ³ with mechanical stirring. The speed of rotation of the mixer was constant and amounted to 2800 min ^-1 . Water pulp NPK with a density of ~ 1.45 kg / dm ³ in an amount of 0.7 dm ³ (400 g solid) was loaded into an autoclave and the calculated amount of a surfactant, a solution of technical lignosulfonates (LST), was introduced. The total consumption of LFB in all experiments was 8 g / kg (NPK), including: 4 g / kg was loaded into the autoclave simultaneously with the initial feed and 4 g / kg was fed into the process using the “monjus” 15 minutes after the start experience. After loading the pulp and surfactant, the autoclave was sealed, and stirring and electric heating were turned on. When the operating temperature was reached, oxygen was supplied to the autoclave; after the working temperature and pressure were established, the test time began. Leaching was carried out at a temperature of 150 ° C and an oxygen pressure of 0.9 MPa for 120 minutes. At the end of the set time, the autoclave was cooled by supplying water to the refrigerators while the pulp was stirred.

A sample was taken from the oxidized pulp discharged from the autoclave, in which the density and pH were measured, after which the whole sample was passed through a sieve and granules with a particle size of plus 150 μm were isolated, washed with water, dried and weighed. The solid and liquid phase of the sample and granules were analyzed. The effectiveness of the method was evaluated by the results of leaching: by the content of sulfur-sulfide granules (mass of melt) in the oxidized pulp and the degree of decomposition of pyrrhotite during the experiment. Since in this experiment, when the NPD was leached, a sulfur sulfide melt (“goat”) was obtained, which indicated a complete disruption of the pyrrhotite oxidation process, laboratory flotation of the oxidized pulp was not carried out.

Example 2 (experiment 2 tables) - the implementation of the prototype method.

The composition of the initial high-sulfur NPK and equipment are the same as in example 1. The difference is that to the sample of the initial NPK before the autoclave-oxidative leaching was added “ordinary” pyrrhotite concentrate of the Talnakh enrichment plant in the amount of 66% by weight of the NPK, which plays the role of mineral stabilizing additives. The "ordinary" pyrrhotite concentrate (RPK) was characterized by a high content of gangue (22.25%) and had the following chemical composition: 1.67% Ni; 0.36% Cu; 0.072 Co; 42.2% Fe; 25.1% S; 59.3% P _about ; 12.3% SiO ₂ ; 3.77% CaO; 2.57% MgO; 3.61% Al ₂ O ₃ . The resulting mixture with a mass ratio of copper to pyrrhotite 1: 85.7 with stirring was repulped using recycled water from the hydrometallurgical production of the Nadezhda Metallurgical Plant.

The autoclave oxidative leaching was carried out in the same mode as in Example 1. A sample was taken from the oxidized pulp discharged from the autoclave, in which the density and pH were measured, after which the whole sample was passed through a sieve and granules with a particle size of plus 150 microns were separated, washed with water , dried and weighed. The effectiveness of the method was evaluated by leaching results: by the content of sulfur sulfide granules in the oxidized pulp, the degree of decomposition of pyrrhotite during the experiment, and indicators of sulfur sulfide flotation — by the content and losses of nickel and platinum group metals in the sulfide flotation tailings, and the level of oxide iron in the sulfur sulfide concentrate. The efficiency of the method is the higher, the lower the content and, accordingly, the extraction of Nickel and PGM in the tailings of sulfonated sulfide flotation, and also, the higher the quality of the resulting sulfonated sulfate concentrate (SSC), i.e. the lower its iron oxide content.

The deposition of non-ferrous metals from an oxidized pulp solution was carried out by crushed metallized iron pellets in a laboratory temperature-controlled titanium reactor with a capacity of 1.5 dm ³ . The pulp was mixed in the reactor by a turbine single-tier mixer with a fixed rotation speed. The pulp temperature during deposition was maintained with an accuracy of ± 1 ° C. Dosage of the precipitant (crushed pellets) in the treated pulp was carried out in four equal portions during the first 20 minutes. The experiments were carried out with the following parameters:

- the volume of pulp in the reactor, dm ³ - 0.5;

- the density of the initial pulp, kg / dm ³ - 1.45 ± 0.02;

- process temperature, ° С - 95 ± 1;

- the content of metallic iron in the precipitant,% - 78.9;

- particle size distribution

precipitant composition: - 96.4% cell. less than 150 microns;

- the number of revolutions of the mixer, min ^-1 - 500;

- the duration of the process, min - 40;

- residual nickel concentration in solution

pulps after deposition, g / dm ³ - 0.25 ± 0.05.

The pulp flotation after the deposition operation was carried out in a closed cycle in a laboratory flotation machine with a working volume of the chamber 1 dm ³ . The process scheme included: the main, control flotation and three cleanings of the rough sulfur-sulfide concentrate (foam product of the main flotation). Butyl xanthate was used as the main collector reagent, and DT motor fuel according to GOST 1667-68 was used as auxiliary. This combination of reagents, as shown by the practice of the GMF NMZ, provides high results of sulfosulfide flotation. Collector reagents were used in the form of an emulsion in the amount (g / t solid in flotation feed): xanthate - 300; motor fuel - 500. Butyl aeroflot (5 wt.% of the mass of motor fuel) was added to stabilize the emulsion obtained in a special agitator. The collector in each experiment was filed at one point - in the head of the main flotation. The duration of the individual stages of flotation was, min:

- main + control flotation - 10;

- I cleaning - 6;

- II cleanup - 4;

- III cleaning - 3.

The solid flotation products were separated from the solution on a vacuum funnel, the cakes were dried, weighed and analyzed for nickel, elemental sulfur (concentrate, tails) and oxide of iron (concentrate). The yield and chemical composition of the products calculated the loss of valuable components with tails.

The initial mixture of high-sulfur NPK and RPK contained 3.23% nickel and 31.9% sulfur with a mass ratio of copper to pyrrhotite 1: 85.7. The autoclave leaching process was complicated by significant granule formation: the content of sulfosulfide granules of class plus 150 microns in the oxidized pulp was 20.3%; mass fraction of elemental sulfur in granules - 56.8%. Due to the screening of sulfides by molten sulfur, the degree of decomposition of pyrrhotite was rather low - 72.6%. As a result of material re-aggregation in the autoclave leaching operation and a low degree of pyrrhotite decomposition, unsatisfactory indicators of serosulfide flotation (SSF) were obtained. SSF tails contained 1.02% nickel and 7.1 g / t total platinum group metals (PGMs); losses with tails amounted to: nickel - 37.9%; the amount of PGM - 58.4%. The resulting sulfosulfide concentrate (CCK) contained 17.6% iron oxide.

Example 3 (experiment 3 tables) - the proposed method

The composition of the initial high-sulfur refinery, the equipment used, and the conditions of all operations are the same as in Example 2. The difference is that the tailings of flotation beneficiation of solid sulfide copper-nickel ores of the Talnakh ore dressing plant were introduced into the initial refinery as a mineral stabilizing additive 21.2% of the mass of the CDD. The initial mixture of high-sulfur NPK and flotation tailings (CF) contained 3.57% nickel and 30.5% sulfur with a mass ratio of copper to pyrrhotite 1: 69.2. The mass ratio of pyrrhotite to the sum of silica and alumina in the mixture was 1: 0.18. Granules of class plus 150 μm were absent in the oxidized pulp of autoclave leaching. The degree of decomposition of pyrrhotite was 97.6%. SSF tails contained 0.18% nickel and 2.3 g / t of PGM; losses with tails amounted to: nickel - 4.3%; the amount of PGM - 23.1%. The resulting sulfosulfide concentrate contained 12.2% iron oxide.

Example 4 (experience 22 tables) - the proposed method

The equipment used and the conditions of all operations are the same as in Example 3. The difference is that a copper concentrate was added to the initial NPK to simulate high-honey raw materials, and the consumption of mineral stabilizing additives (HF) ensured the mass ratio of pyrrhotite to the sum of silicon dioxide and aluminum oxide in the loaded mixture 1: 0.67. The mixture contained 2.04% nickel and 18.8% sulfur with a mass ratio of copper to pyrrhotite equal to 1: 40.5 (material is high-copper). In this example, granules of class plus 150 μm were not formed during the leaching of the mixture. The degree of decomposition of pyrrhotite was 94.9%. The tails of the SSF contained 0.11% of nickel and 1.2 g / t of the amount of PGM at the level of their losses with tails of 10.2 and 29.1%, respectively. Mass fraction of oxide iron in SSC amounted to 12.9%.

The table shows examples that differ in the composition of the mixtures obtained, as well as in the nature and flow rate of the used mineral stabilizing additives.

According to the obtained experimental results (experiments 3-5, 8-19, 22-24 and 27-31), the addition of alkali and / or alkaline earth metals with a complex alumina-silicon-oxygen radical (aluminosilicates) to a high-sulfur NPD allows to completely suppress the granulation process during its autoclave-oxidizing leaching and provides decomposition of pyrrhotite by 92.4-99.1%, regardless of the ratio of copper to pyrrhotite in the processed NPK. Flotation of pulp obtained by leaching high-sulfur NPK by the proposed method provides extraction in SSC: nickel - 77.0-96.1%; the amount of PGM - 68.0-80.9%. Mass fraction of oxide iron in the obtained SSC is 11.6-13.1%.

By the level of valuable components in the tailings of the SSF (0.10-0.18% nickel; 1.1-2.9 g / t of PGM total) and the quality of the concentrates obtained, it can be concluded that the processing efficiency of high-sulfur nickel-pyrrhotite raw materials , the leaching of which is complicated by the tendency to granule formation, using the proposed method becomes no lower than when processing easily open "ordinary" pyrrhotite concentrates of the current production.

The optimal consumption of the mineral stabilizing additive is determined by the mass fraction of copper-containing sulfides in the NPK: upon receipt of a low-copper concentrate (the mass ratio of copper to pyrrhotite in the mixture is less than 1:55), the optimal ratio of pyrrhotite to the sum of silicon dioxide and aluminum oxide in it lies in the range 1: 0.05 -0.33); for high-honey concentrates (the mass ratio of copper to pyrrhotite in the mixture is greater than or equal to 1:55), the optimal value of this parameter is in the range 1: (0.5-0.8).

When the values of the dosage parameters of the mineral stabilizing additive exceed the declared range (op. 6, 7 and 25, 26), the main technology indicators deteriorate sharply, approaching the results obtained by the prototype method (op. 2 and 21). In particular, in op. 6 with a prohibitively low ratio of pyrrhotite to the sum (SiO ₂ + Al ₂ O ₃ ) in the initial mixture of NPK and mineral stabilizing additive (HF) equal to 1: 0.37, nickel losses with tails of SSF increased from 3.9-7.8% to 9.5%, and the loss of the amount of PGMs increased from 19.1-28.7% to 36.4%. Similarly in op. 25, the experiment with a prohibitively low ratio of pyrrhotite to total (SiO ₂ + Al ₂ O ₃ ) caused a decrease in the degree of decomposition of pyrrhotite from 93.8-95.2% to 84.2%. Moreover, nickel losses increased by 5.4-7.1 abs.% And by 17.5-21.6% abs. the loss of the amount of PGM with tails of the SSF increased.

In an experiment characterized by a prohibitively high ratio of pyrrhotite to the sum (SiO ₂ + Al ₂ O ₃ ) equal to 1: 0.04 (op. 7), in the course of leaching, serosulfide granules of the plus 150 μm class were formed, the yield of which was 17.3% . As a result of this, the degree of decomposition of pyrrhotite decreased from 92.4-99.1% to 83.7%, and the subsequent enrichment of oxidized pulp took place with low selection indicators: the losses of nickel and the amount of PGM with tailings of sulfosulfide flotation were 13.6 and 45, respectively. 3%, and the obtained SSC contained 18.6% of iron oxide. Similarly, in the experiment on leaching of a high-honeyed NPK, characterized by the mass ratio of copper to pyrrhotite 1: 55.0 (op. 26), with a prohibitively high ratio of pyrrhotite to the sum (SiO ₂ + Al ₂ O ₃ ) equal to 1: 0.44 formed sulfosulfide granules (class plus 150 microns) in an amount of 19.3%. This led to a sharp deterioration in the indicators of oxidative opening of pyrrhotite in comparison with the claimed range of ratios (op.22-24, 27-31), which, in turn, decreased the indicators of subsequent sulfosulfide flotation. The degree of decomposition of pyrrhotite in this experiment was only 81.6% compared to 94.2-95.3% achieved by leaching close in composition NPK in the proposed mode. Losses of nickel and the amount of PGM with tailings of SSF were respectively 31.9 and 52.6%, which is significantly higher than in experiments by the proposed method. The obtained SSC was of low quality: the content of oxide iron in it was 17.5%, which is 4.4–6.3 abs.% Higher than in experiments with the declared range. The increased content of oxide iron in the SSC is highly undesirable, since in the subsequent processing of the concentrate, this factor leads to the overuse of expensive reagents, energy resources and reduces the output of target metal products.

A joint analysis of the results of op.6 and op.26 shows that the optimal ranges of the mass ratio of pyrrhotite to the sum (SiO ₂ + Al ₂ O ₃ ) characteristic for leaching concentrates with a low (op.6) and high (op.26) copper ratio to pyrrhotite, do not have common borders (do not “close”). This regularity was discovered for the first time and, apparently, is one of the consequences of the catalytic effect of copper sulfide minerals on the sulfur aggregation process. The suppression of this process with a monotonic change in the ratio of copper to pyrrhotite in sulfide concentrates with a high pyrrhotite content requires a discrete change in the mass ratio of pyrrhotite to the sum (SiO ₂ + Al ₂ O ₃ ), which is achieved by a discrete change in the flow rate of the stabilizing additive introduced.

In general, the analysis of the results shows that the use of the proposed method for the processing of sulfide concentrates with a high content of pyrrhotite, which are prone to granulation during autoclave-oxidative leaching, compared with the prototype method (op. 2 and 21) allows for optimal dosage of aluminosilicates (op. 3 -5, 8-19, 22-24 and 27-31) completely eliminate the formation of granules and melt (“goats”), as well as significantly increase the intensity and depth of the pyrrhotite oxidation process: the degree of decomposition of pyrrhotite increases by 19.8-26 , 5 abs.%. Along with this, higher rates of material selection are achieved during subsequent sulfur-sulfide flotation: the losses of nickel and the amount of platinum metals with tails are lower by 30.1-34.0% and 29.7-39.3 abs.%, Respectively, and the obtained CCK contains oxide iron 4.6-6.8 abs.% less. In addition, the proposed method avoids serious technical disadvantages inherent in the prototype method and is analyzed in detail in its description.

The industrial implementation of this method will allow combining the high efficiency of new technological schemes for the concentration of pyrrhotite ores, including the production of products with a high content of pyrrhotite, with highly efficient processing of the latter using autoclave-oxidative leaching technology.

When studying the patent and scientific and technical literature of any signs that are identical in technical essence with the distinguishing feature of the proposed technical solution, is not revealed.

Aluminosilicates and synthetic materials based on them have found wide application in various hydrometallurgy processes, in particular, natural aluminosilicates belonging to the mineralogical group of hydrated mica, montmorillonite or zeolite, which are mineral ion exchangers, are used to purify water from calcium and magnesium cations in order to control the composition liquid phase flotation and hydrometallurgical pulps. Mica ion-exchange minerals and montmorillonite are used under the name of bleaching earth in the production of oils, soaps, etc. (Plaksin I.N., Tetaru S.A. Hydrometallurgy using ion exchangers. - M .: Metallurgy, 1964. - S.7-13) . Synthetic aluminosilicates - zeolites - which are mineral molecular sieves, are used in the processes of: separation of unsaturated and aromatic hydrocarbons based on selective sorption; drying of gases and organic liquids: separation and purification of gases; improving the quality of motor fuels, etc. (Keltsev I.V. Fundamentals of adsorption technology. - M.: Chemistry, 1976, - 511 pp.).

In all these processes, aluminosilicates perform the function of either mineral ion exchangers or molecular sieves intended for the separation and purification of chemical compounds and products. Therefore, here aluminosilicates have a fundamentally different purpose than in the process of autoclave-oxidative leaching of sulfide materials.

Aluminosilicates are most widely used in the silicate industry for the production of: chemically resistant (acid-resistant) materials; aluminosilicate refractories; ceramics; construction and binders; building-technical glass, etc. (Duderov I.G., Matveev G.M., Sukhanova V.B. General technology of silicates. - M.: Stroyizdat, 1987. - 560 p.).

In this area of production, the use of aluminosilicates is also fundamentally different from their purpose in the proposed method for processing sulfide concentrates.

There are no data on the use of aluminosilicates and products containing them in the processes of autoclave-oxidative leaching of sulfide concentrates in known literature. Moreover, there are ideas that waste rock minerals, including aluminosilicates, have a harmful effect on the oxidative leaching of pyrrhotite-containing materials. According to some researchers, the negative influence of rock minerals is due to two factors:

- a decrease in the acidity of the medium as a result of decomposition of the rock, causing a decrease in the speed of the process (the so-called “alkaline inhibition”) and the depth of oxidation of pyrrhotite;

- absorption of heavy metals from the solution by highly dispersed mineral sediments formed during the decomposition of rock minerals, which leads to a decrease in the extraction of valuable components in the target product - autoclave concentrate (Borbat V.F., Leshch I.Yu. New processes in the metallurgy of nickel and cobalt. - M .: Metallurgy. 1976. - S.56-57).

From other literary sources at the time of the invention it was known that no solid stabilizing additives could not suppress the granulation process during autoclave-oxidative leaching of high-sulfur nickel-pyrrhotite concentrates. Based on this conclusion, the authors of the work proposed the option of leaching high-sulfur NPK to obtain sulfur granules (Abramov NP // Non-ferrous metals. - No. 7. - 1992. - C.11).

It is also known that as a criterion for the emulsifying-dispersing properties of waste rock, which provides complete suppression of the process of sulfur aggregation during leaching of “ordinary” pyrrhotite concentrates, the ratio in the rock (CaO + MgO) / SiO _{2 was} determined, which, according to the authors, should not be lower than 0 , 3. With values of this criterion less than 0.3, the formation of granules does not suppress. Another condition for the absence of granules during leaching is that the mass content of the rock in the concentrate should be at least 4-6% (Onatskaya AA, Shneerson Ya.M., Mitenkov GA // Non-ferrous metals. - No. 1. - 1992. - S. 31-33). At the same time, during the leaching of high-honeyed NPKs diluted with “ordinary” pyrrhotite concentrate to a rock content of 11–13% in the mixture at a mass ratio of (CaO + MgO) / SiO ₂ = 0.4–0.5, formation of sulfosulfide melt occurred (“Goat"), the yield of which was ~ 33% (Abramov NP // Non-ferrous metals. - No. 7. - 1992. - C.11).

It follows that the known laws established for the leaching of “ordinary” pyrrhotite concentrates cannot be extended to a similar process of leaching sulfide concentrates with a high content of pyrrhotite, in particular, high-sulfur NPK. Another convincing evidence of this fact is that in the proposed method of completely suppressing the process of granule formation during the leaching of high-sulfur NPKs, it was possible to achieve by introducing aluminosilicates into the concentrate, characterized by the ratio (CaO + MgO) / SiO ₂ much lower than 0.3.

In addition, in the well-known from the literature criteria for the emulsifying-dispersing properties of gangue (CaO + MgO / SiO ₂ ), the silica group is in the denominator (Onatskaya AA, Shneerson Ya.M., Mitenkov GA // Non-ferrous metals. - No. 2. - S.31-33). From this it could be concluded that minerals with a high content of silicon dioxide, in particular, aluminosilicates, cannot be considered as a mineral stabilizing additive, especially those that do not contain magnesium and / or calcium.

Thus, the proposed technical solution in the main points of principle does not coincide with the known literature data. In addition, the obtained experimental results, convincingly confirmed by the results of industrial tests, cast doubt on the validity of the generalizations expressed in well-known publications regarding the laws governing the suppression of the granulation process during the leaching of sulfide materials. The proposed dosage regimen of aluminosilicates completely eliminates granule formation during leaching of extremely complex raw materials - high-sulfur NPKs with a high copper content - using minerals and products containing them with a low level of (CaO + MgO) / SiO ₂ ratio. This leads to new ideas about the mechanism of the stabilizing effect of rock minerals, which has not yet found a sufficient theoretical explanation, and indicates the compliance of the claimed object with the criterion of "Inventive step".

CONVENTIONS AND ACCEPTED ABBREVIATIONS

NPK - sour nickel-pyrrhotite concentrate;

MK - copper concentrate;

RPK - "ordinary" pyrrhotite concentrate with a high content of waste minerals;

HF - tailings of the Talnakh processing plant of the ZF OJSC MMC Norilsk Nickel;

KGR - silica-alumina horn;

QGD - contact gabbro-dolerite;

VZV - Vesuvian (a mineral from a subclass of island aluminosilicates);

KRD - cordierite (a mineral from a subclass of ring aluminosilicates);

AUG - augite (a mineral from a subclass of chain aluminosilicates);

MSC - muscovite (a mineral from the subclass of layered aluminosilicates);

PLG - plagioclase (a mineral from a subclass of framework aluminosilicates);

KR - quartz horn;

PPO - an intermediate product of the enrichment of sulfide copper-nickel ores of the Talnakhsky processing plant, which is a hydrocyclone discharge of a mixture of 2 products: material of a storage pond and sludge from a crushing and screening section;

ANL - analcime (a mineral from the group of natural zeolites);

ШБЗ - chabazite (a mineral from the group of natural zeolites);

NZN - nozean (a mineral from the group of natural zeolites);

TsN - zeolite N (synthetic zeolite);

CH - zeolite X (synthetic zeolite);

Sod-e - content;

Ex. - extraction;

SSK - sulfosulfide concentrate;

PGM - platinum group metals;

Kl. - class size;

microns - microns.

Claims (9)

1. A method of processing sulfide concentrates with a high content of pyrrhotite, comprising introducing a mineral stabilizing additive into the initial concentrate, autoclave oxidative leaching of the mixture in an aqueous pulp under oxygen pressure at a temperature above the melting point of sulfur in the presence of a surfactant with the transfer of non-ferrous metals into solution, sulfur to elemental, iron to oxides, the deposition of non-ferrous metal sulfides from a solution of oxidized pulp, followed by the release of non-ferrous metal sulfides in and elemental sulfur by flotation in a collective sulfur-sulfide concentrate, and iron oxides in dump tailings, characterized in that, as a mineral stabilizing additive introduced into the initial sulfide concentrate with a high content of pyrrhotite, alkaline and / or alkaline earth metal compounds with a complex aluminum-silicon-oxygen radical are used ( aluminosilicates) added in an amount providing a mass ratio of pyrrhotite to the sum of silicon dioxide and aluminum oxide in the resulting mixture 1: (0.05 ÷ 0.33) with mass wearing copper to pyrrhotite less than 1:55, or providing a mass ratio of pyrrhotite to the sum of silicon dioxide and aluminum oxide in the resulting mixture 1: (0.5 ÷ 0.8) with a mass ratio of copper to pyrrhotite more than or equal to 1:55. 2. The method according to claim 1, characterized in that the rock-forming aluminosilicates in the composition of the ore-bearing rocks are used as a mineral stabilizing additive. 3. The method according to claim 2, characterized in that as the ore-bearing rock containing aluminosilicates, the final and intermediate products of the enrichment of sulfide ores are used. 4. The method according to claim 3, characterized in that the tailings of the concentration of sulfide copper-nickel ores are used as the final beneficiation products. 5. The method according to claim 3, characterized in that the product of gravity separation of the rock tailings of the beneficiation of sulphide copper-nickel ores concentrating aluminosilicates is used as the final beneficiation products. 6. The method according to claim 1, characterized in that natural zeolites are used as aluminosilicates. 7. The method according to claim 1, characterized in that synthetic zeolites are used as aluminosilicates. 8. The method according to claim 3, characterized in that aluminosilicates are used as a mineral stabilizing additive in the composition of metamorphic rocks of a contact halo of intrusions. 9. The method according to claim 3, characterized in that as a mineral stabilizing additives use aluminosilicates in the composition of intrusive rocks.