USRE17001E - Ture robert haglund - Google Patents

Description

Reissued June 19, 1928.

TUBE ROBERT HAGLUNI), OF STOCKHOLM, SWEDEN, ASSIGNOR TO PATENT OFFICE.

INTERNATIONAL PATENT CORPORATION, A CORPORATION OE MARYLAND.

PROCESS OF TREATING ORES CONTAINING A REFRACTORY OXIDE.

No Drawing. Original No. 1,569,483, dated January 12, 1926, Serial No. 579,964, filed August 5, 1922. Application for reissue filed October 29, 1927. Serial No. 229,786.

The object of the present invention is: out of oxidie raw materials containing several oxides to separate one or more oxides, for example SiO Fe 'O CaO etc. This 5 separation or purification is according to the present invention eifected by a process wherein the oxide or oxides from which the raw material is to be purified, are separated by reduction or by conversion into nonoxidic compounds by the smelting of the raw material containing the oxides in question, for example in an electric furnace, together With sulphurous materials and the neccssary reducing agents, the process being carried out in such a Way as to result in the formation of a melt containing both sulphide and oxide, but entirely or essentially free from the oxides to be separated, i. e. in such a. Way that the melted mass is substantially free from such oxides from which the raw material is to be purified, The melt containing sulphide and oxide thus obtained can be used for various purposes: thus, for example, if its oxide content consists entirely, or in essentials, of aluminum oxide, it may be used as raw material for the manufacture of alloys. As in the cooling of the sulphideoxide melt, its content of oxid substantially crystallizes, the melt is moreover very well adapted for the production, of pure or purified oxides, or of oxide compounds or mixtures of oxides purified from oxides, which is effected by the separation of the sulphide content, for example by treatment of, the crystallized melt with acids, alkalics. water or; steam. V 1,

fishould the sulphide-oxide melt not, be. sufficiently pure, it maybe subjected to -remelting, for example; together with reduc ing agents and, if. necessary,-adt litional admixtures ofjsulphurousmaterials.

The process is. particularly well adapted I for theproductionofaluminiumbxide, es-

pecially of the kind which-wissuificiently puretoebe used. for the manufacture "of pure aluminium metal by meltrelectrolysls. Asin the process, the aluminium oxide .is obtained, in acrysulllized1 form, itgcan also be used injurious I cooling,

for grinding purposes, for example for the manufacture of grinding discs, or. the like. Moreover, aluminium oxide, produced in accordance with the present process is a very suitable material for the manufacture of refractory bricks. If, for example, in order I to attain a certain grinding action, it is desired that the aluminium oxide should contain other oxides, this may be effected by regulating the reduction in suitable Way during the smelting and, if necessary, by the addition during the smelting of any special admixtures that may be required. The process is also suitable for the manufacture of other oxides. Thus, it is possible in accordance with the process to manufacture crystallized magnesium oxide, either pure or with a certain desired content of other oxides.

.As crystallized magnesium oxide manufactured in accordance With the process does not, like amorphous oxide, show a great tendency to shrink at high temperatures, it is particularly Well adapted for the'manufacture of refractory bricks. Amongst other oxides Which can be manufactured in a crys' tallized form in accordance With the process may, as example, be mentioned, alkaline earth oxides, zirconia (zirconium-oxide), and others.

As the process is of great importance for the manufacture of aluminium oxide, such manufacture is by Way of example described in greater detail here below:

.I .first' produce a melt containing as its principalcomponent a mixtureof A1 0, and one ormoresulphide's, forexample ,AI S which have the capacity of,dissolvingialwz minium oxide in a molten state, but out of, which melt aluminium oxide erystallizes. on is first of. all made. This melt containingoxide and sulphide may be produced for examplebysmeltingin an electricarc furnace the raw materialin the presence of reducing agents,-such as coke,;-small coal, charcoal, calcium carbide, Zeta. in order en tirelyor, essentially to. reduce certain I oxides 5 SUCh-QS together with A1 0 are contained in the raw materials. By treating this melt so that the sulphide is decomposed and separated ofi, ordissolved out, a crystal mass consisting of practically purealuminium oxide is obtained.

The most suitable raw material containing A1,,O for the manufacture of aluminium oxide in this manner is bauxite, but it is also possible to employ other minerals, or the like containing A1 0 such as chamotte, feldspar, alum schists, leptite, clays, for example those containing carbon, coal waste containing A1 0 and others, as well as products containing A1 0 manufactured in accordance' with some method, such as, for example, alundum contaminated by. SiO, or FeO. Several different kinds of-raw materials containing aluminium may, of course, be used simultaneously or toget er. I

The following may serve as examples of the process for the manufacture of a sulphide-alumina belt of the 1 kindabove referred to Example 1.Bauxite if desired after previous drying and heating to incandescenceis melted in an electric furnace together with ferrous sulphide and coal. The coal is added'in a quantity suff cient to reduce ferro-, silico-, andv titanic oxygen compounds in the bauxite, and, for example, 25% of the A1 0 in the bauxite. The re duced iron, silicon and titanium alloy themselves in the main with one another, and the alloy sinks to the bottom in the furnace. The reduced aluminium is converted with FeS into iron, which enters as an ingredient into the alloy, and A1 5 which absorbs by dissolvingthe remaining A1 0 in the bauxite, if desired, the quantity of FeS can be so chosen that part of the reduced aluminium metal is obtained in the alloy, with a view to diminish the risk of too high a content of sulphur in the said alloy. The smelting should preferably be carried on continuously. I In this way there will be obtained on tanning the furnace partly ferrosilicon or the like and partly a sulphidealumina melt in which latter, on cooling, A1 0 crystallizes out.

E wample 2.-Bauxite, which may be calcined, is melted, preferably in an electric furnace, together with reducing agents in a quantity sufficient to reduce in the main oxides such as FeO, SiO TiO etc., which in addition to A1 0 are present in the bauxite and a sulphide, for example Gas or Aus The A1 0 in the bauxite is thereby dissolved by the sulphide, and then crystallizes on cooling. Ferro-silicon is moreover obtained. In order to beassured of obtaining reduced silicon bound in the alloy, it is also suitable to charge iron in some form, for example iron filings, or else a ferro-compound together with reducing agents.

vAsis evident from the above examples, the sulphide in the sulphide-alumina melt can be obtained in the processes by the addition of sulphides with a lower heat of formation than A1 8 which sulphides are converted with aluminium, or, in the presence of reducing agents, with A1 0 into aluminium sulphide. If it desired to obtain a sulphide other than Al S in the sulphide-alumina melt, one may add substances which in the presence of the sulphide admixtures above referred to give rise to sulphide with a higher heat of formation than Al s Such admixtures may. for example, consist of 0:10, MgO, BaO, or others, or else compounds or raw materials containing such substances, or again alloys or metals containing substances which give rise to sulphides with a higher equivalent generating heat than Al S as, for example, fer ro -manganese. sulphides of the kind above indicated suitable for the process, i. e. each which have a lower heat of formation than,

Al s are sulphides of heavy" metal such as FeS, Cu S, etc, It is also possible to use minerals, or other products containing such sulphides, for instance magnetic iron pyrites (Fe S,) for example a nickeliferous kind of such pyrites, ordinary pyrites, copper pyrites, copper glance, galena, crude copper (copper: matte) ore etc, Obviously also other sulphur compounds of these metals, such as sulphates, may be employed, which however require a special reducing agent to convert them into sulphides. It is alsopossible to employ simultaneously several of the above mentioned sulphur compounds.

In lieu of, or simultaneously with, the above sulphur compounds, it is also possible to employ one or more sulphides which have an equal or higher equivalent generating heat than A1 5,, which sulphides in the main do not undergo chemical transformation in the process, but enter into the sulphide-alumina melt as the sulphide or sulphides which in -a molten state constitute the solvent for A1 0 sulphides suitable for this purpose are, for example, Al S sulphides of alkali and alkaline earth metals, such as K S, Na S, BaS, CaS, MgS, etc. These sulphides may be exchanged wholly or partially for the corresponding sulphates or sulphites, for example, CaSO BaSO etc., together with reducing agents required for their reduction. In certain cases sulphur also may be used as an admixture for the formation of the required sulphide, for instance if any carbide, for example calcium carbide, is employed as a reducing agent in the process.

In the procedure according to Example 2 it was stated that-a separate addition of iron could be made in order to ensure that silicon should be bound in the alloy. The iron, both in this and in other forms of the process in wide limits.

may obviously be replaced entirely or par tially by some other metal, e. g. copper,moreover in order to obtain such metal, the admixtures may obviously consist of metal 0X- ides, e. g. F e 0 FeO, Fe o etc., together with reducing agents.

The quantity of sulphide in the sulphide alumina melt may obviously be varied with- It is suitable-to work with a sulphide content of 2040%, but in certain cases a considerably lower content may suffice, for example down to 10% or lower. In case of a higher content of sulphide the crys tals will be larger, whence, if large crystals are desired, one should work with a high percentage of sulphide, e. g. up to or more. The size of the crystals may also be regulated by changes in the rate of cooling of the sulphide-alumina melt.

The sulphide-alumina melt is far more fusible than A1 0,, and in determining the percentage of sulphide, the obtaining of a low melting-point may also be taken into consideration.

The sulphide-alumina melt separates itself easily from the alloy simultaneously obtained, and is treated after the cooling for the production of A1 0 This procedure may, for example, be carried out by treating the melt, preferably after crushing, with some acid, e. g. ILSO HGl, HNO acetic acid, etc. or a mixture of two or more such acids. By this means the sulphide is decomposed and dissolved. The melt is as a rule contaminated with heavy metal sulphide, e. g. FeS. On the melt being dissolved with acid in excess, this impurity enters into solution. As an undissolved remainder is obtained a crystal mass of A1 0 which, if necessary, can be freed by washing or decantering from minor impurities insoluble in the acid, e. g. Sio and, if desired, it may be treated for the same purpose with alkaline lye, e. g. NaOH. The crystal mass of A1 0 is then dried.

If the sulphide-alumina melt contains AI S itis possible out'of the solution obtained in the treatment vof the melt if necessary after purifying from impurities such as salts of iron to produce aluminium hydrate and to produce out of the latter pure A1 0 or else the solution may be used for the production of aluminium salts, e. g. aluminium sulphate.

The dissolution of the sulphide in the sulphide-alumina melt may also be carried outin two or more stages. This is especially advisable if the sulphide consists of aluminium sulphide. If a deficit of acid is used the first time, there will be obtained a solution practically free from iron, as the iron sulphide is not dissolved until practically all the Al s is dissolved. In the treatment of the remainder with new acid in excess, the re mainder of the AI S and any FeS that occurs will be dissolved. On the dissolving of the example, .of Na i), K S, or BaS, it. enters into solution on being treated with water. If the sulphide consists of-AhS it is decomposed under the development of H S and the formation of aluminium hydrate. The aluminium hydrate can then be dissolved with acids or alkalies and be treated for the production of pure A1 0 or for aluminium salts, or else the aluminium hydratecan be separated by washing or stirring and decantering from the crystal of A1 0,. The latter should then be treated with acid for the dissolving of any impurities, such as FeS. The washed or decantered aluminium hydrate can, after drying and eventually heating to redness, be used as raw material for renewed production of a sulphide-alu mina melt, or else be used as raw material for the manufacture of pure A1 0 or aluminium salts, for example in accordance with methods which in themselves are known.

Any metal, magnetic sulphide or the like which may occurin the alumina crystal mass or in the decanted aluminium hydrate may eventually be separated by methods commonly employed in the separation of ore, such as by magnetic or electrostatic separation, etc.

The manufacture of other oxides in accordance with the process is carriedout in a manner analogous to the procedure for the manufacture of A1 0,. In the manufacture of crystallized MgO burned magnesite may, for example, be used as raw material. The chief impurities in the latter are CaO, SiO and F8 0,. The separation of these oxidic impurities may for example be carried out by smelting the magnesite together with such a quantity of a reducing agent that SiO and,

Fe O are reduced and that CaO and possibly some MgO react with a sulphurous admixture made for the purpose, for example magnetic iron pyrites or FeS, and form (la-S and Mg'S. Theremaining MgO will then be dissolved in a molten condition into the calcium and magnesiumfsulphides and will crystallize on cooling. Gas and MgS are separated oif afterwards, e. g.by soaking with water or diluted acids.

Having thus described my invention I declare that what I claim is:

1. The process of treating ores containing iron, silicon or titanium and arefractory metal oxide which does not fuse below 1940 C. comprising reducing oxides of iron, silicon or titanium and dissolving the refracmetal oxide which does not fu'se below 1940? C. comprising reducing oxides of iron, silicon or titanium and dissolving the refractory metal oxide in a sulfide containing slag by fusing the ore with a sulfide yielding material and a reducing agent, the proportion of sulfide-containing material being such that the slag contains not to exceed 75% of sulfide, the balance of the slag being formed by the dissolved refractory bxide and separating the reduced iron, silicon or titanium from the sulfide-refractory-oxide slag.

3. The process of treating ores containing iron, silicon or titanium and a refractory metal oxide which does not fuse below 1940" C. comprising reducing oxides of iron, silicon or titanium and dissolving the refractory oxide in a sulfide containing slag by fusing the ore with metallic sulfides and a reducing agent, the proportion of the metallic sulfides being such that a part of the refractory metal oxide remains unconverted in the slag and separating the reduced'iron, silicon or titanium from the sulfide-refractory-oxide slag.

4. The process of removing oxides of iron, silicon or titanium from ores containing a diiiicultlyreducible metal oxide which does not fuse below 1940 C., which comprises heating the ore with a metallic sulfide and a reducing agent, the proportion of metallic sulfide being such' that a part of the difii- I cultly reducible metal oxide remains unconverted in the slag and tapping and separating the reduced iron, silicon or titanium and the sulfide-refractory-oxide slag.

5. The process of removing oxides of iron, silicon or titanium from ores containing refractory metal oxides which do not fuse be low 1940 C., which comprises heating the ore with metallic sulfides and a reducing agent, the proportion of metallic sulphides being such that a part of the refractory metal oxides remains unconverted in the slag, separatingthe reduced iron, silicon or titanium from the sulfide-refractory-oxide slag and separating the refractory oxides from the slag.

6. The process of removing oxides of iron, silicon or titanium from ores containing refractory metal oxides which do not fuse be low 1940 0., which comprises heating the ore with metallic sulfides and a reducing agent, the proportion of metallic sulfides being such that a part of the refractory silicon or titanium from ores containing.

metal oxides which do not fuse below 1940 C., which comprises heating the ore with metallic sulfides having a heat of formation not higher than aluminum sulfide and a reducing agent, the proportion of metallic sul- -fidesbeing such that a part of the metal oxides remains unconverted in the slag and tapping and separating the reduced iron, silicon or titanium and the sulfide-refractory-oxide slag.

8. The process of removing oxides of iron, silicon or titanium from ores containing difficultly reducible metal oxides which do not fuse below 1940" (l, which comprisesheating the ore with metallic sulfides having a heat of'formation not higher than aluminum sul-\ fide and a reducing agent, the proportion of the metallic sulfides being such that the slag contains not to exceed 75% of sulfide, the balance of the slag bein formed by the dissolved metal oxides and tapping and separating the reduced iron, silicon or titanium and the sulfide-refractory-oxide slag.

9. The process of removing oxides of iron,

silicon or titanium from ores containing re- 7 fractory metal oxides which do not fuse below 1940" C., which comprises heating the ore with metallic sulfides having a heat of formation not higher than aluminum sulfide and a reducing agent, the proportion of metallic sulphides being such that a part of the refractory metal oxides remains unconverted in the slag, separating the reduced iron, silicon or titanium from the sulfide-refractoryoxide slag and separating the refractory oxides from the slag.

10. The process of removing oxides of iron, silicon or titanium from ores containing refractory metal oxides which do not fuse below 1940 (l, which comprises heating the ore with metallic sulfides having a heat of formation not higher than al uminum sulfide and a reducing agent, the proportion of metallic sulphides being such that apart of the refractory metal oxides remains unconverted in the slag, separating the reduced tanium and separating the aluminum oxide from the slag.

13. The process of treating bauxite comprising reducing oxides ofiron, silicon and titanium and dissolving aluminum oxide in a sulfide containing slag by fusing the bauxite with a sulfide yielding material and a reducing agent, .the proportion of sulfideyielding material being such that the slag contains not to exceed 75% of sulfide, the

balance of the slag being formed by the dissolved aluminum oxide and separating the sulfide-aluminum-oxide slag from the reduced alloy.

14. The process of treating bauxite com prising reducing oxides of iron, silicon and titanium and dissolving aluminum-oxide in a sulfide containing slag by fusing the bauxite with a sulfide yielding material and a reducing agent, the proportion of sulphide being such that a part of the aluminum oxide remains unconverted in the slag, separatin the sulfide-aluminum-oxide slag from the reduced alloy and separating the aluminum oxide from the slag.

15. The'process of treating ores containin aluminum oxide comprising reducing oxides of iron, silicon or titanium and dissolving aluminum-oxide in a sulfide containing slag by fusing the ore with a sulfide and a reducing agent, the proportion of sulfide being such that a part of the aluminum oxide remains unconverted 'in the slag, and sepa-- rating the sulfide-aluminuni eexideslag from the reduced iron, silicon or titanium.

16, The process of treating ores containaluminum-oxide comprising reducing oxides of iron, silicon or titanium and dis solving aluminuin-o'xide' in a sulfide containingfsla'g' by fusing the'ore withafsulfide andj' a reducing agent, the proportion of sulphide "being such that a partjof the aluminum oxide remains" unconverted in the slag, separating the 'sulfide-aluminum-oxi'de slag from the reduced iron, siliconfo'r titanium and separating'the aluminum-oxide"from the slag.

17. The process of treatingbauxite comprising reducing oxidesof iron,fs'i1i con; and

titanium' and dissolving'aluminum oxide in f e; ta n slag b j u in t e te with. e eee qe se 'e ee the proportion of sulfide being such that a part of the aluminum oxide remains unconverted in the slag and separating the sulfifie-aluminum-oxide slag from the reduced a 0y. V

18. The process of treating bauxite comprising reducing oxides of iron, silicon and titanium and dissolving aluminum-oxide in a sulfide containing slag by fusing the bauxite with a sulfide and a reducing agent, the proportion of sulphide being such that a part of the aluminum oxide remains unconverted in the slag, separating the sulfide-aluminum-oxide slag from the reduced alloy and separating the aluminum oxide from the slag.

19. The process of treating ores containing iron, silicon or titanium and aluminumoxide comprising reducing oxides of iron, silicon or titanium and dissolving the aluminum-oxide in a sulfide containing slag by fusing the ore With a sulfide having a heat of formation not higher than that of aluminum sulfide and a reducing agent, the proportion of sulfide being such that the slag contains not to exceed 7 5% of sulfide,

'from the reduced iron, silicon or titanium and separating'out the pure aluminum-oxide from the slag.

21. The process of treating bauxite comprising reducin oxides of iron, silicon and titanium and dissolving aluminum-oxide in a sulfide containing slag by fusing the bauxite with a sulfide having a heat of formation not higher than that of aluminum sulfide andva reducing agent, the-proportion of sulfide being such that a part of the aluv minum oxide remains unconverted in the slag and separating the sulfide-aluminumoxide slag from the reduced alloy. a I

22. The process of treating-bauxite comprising reducing oxides of iron, silicon and a sulfide containing slag by fusing. the

bauxite with a sulfide having a heat of fo rmation not higher than that of aluminum sulfide and a reducing agent andseparating the sulfide-aluminummxide slag from the re-[ "duc ed alloy, and separating out the pure alu'minummxide from the slag.

28. The process of removing oxides of iron, silicon or titanium from'ores COIltfllIlf titanium and dissolvingaluminum-oxidein v ing, aluminum oxide which comprises fusing the ore with an iron sulfide and a reducing agent and tapping and separating the sulfide-aluminum-oxide slag and the reduced iron, silicon or titanium and coolin the slag for crystallizing the aluminum oxi e.

24. The process of, removing oxides of iron, silicon or titanium from ores containing aluminum oxide, which comprises fusing the ore with an iron sulfide and a reducing agent and separating the sulfide-aluminumoxide slag from the reduced iron, silicon or titanium and separating out the pure aluminum oxide from the slag.

25. The process of removing the oxides of iron, silicon and titanium from bauxite, which comprises fusing it with an iron sulfide and a reducing agent and tapping and separating the sulfide-'aluminum-oxide slag and the reduced iron-silicon-titanium alloy and cooling the slag for crystallizing the aluminum oxide and regulating the size of the crystals by the rate of cooling.

26. The process of removing the oxides of iron, silicon and titanium from bauxite, which comprises fusing it with an iron sulfide and a reducingagent and separating the sulfide-aluminum-oxide slag from the reduced iron-silicon-titanium alloy and separating out the pure aluminum oxide from the slag.

27. The process of removing oxides of iron, silicon or titanium from ores containing aluminum oxide, which comprises fusing the ore with an iron sulfide and carbon and tapping and separating the sulfide-aluminum-oxide slag and the reduced iron, silicon or titanium and cooling the slag for crystallizing the aluminum oxide.

28. The process of removing oxides of iron, silicon or titanium from ores containing aluminum oxide, which comprises fusing the ore with an iron sulfide and carbon and separating the sulfide-aluminumoxide slag from the reduced iron, silicon or titanium, and separating out the pure aluminum oxide from the slag.

29'. The process-of removing the oxides of iron, silicon and titanium from bauxite, which comprises fusing it with an iron sulfide and carbon and tapping and separating the sulfide-aluminum-ox1de slag and the reduced iron-silicon-titanium alloy and cooling the slag for crystallizing the aluminum oxide and regulating the rate of cooling for forming comparatively small crystals.

30. The process of removing the oxides of 31. The process of removing oxides ofiron, silicon or titanium from ores containfusing the ore with iron pyrites and carbon and separating the sulfide-aluminum-oxide slag from the reduced iron, silicon or titanium and separating out the pure aluminum oxide from the slag.

33. The process of removing the oxides of iron, silicon and titanium from bauxite, whichcomprises fusing it with magnetic iron pyrites and carbon and tapping and separating the sulfide-'aluminum-oxide slag and the-reduced ironLsilicon-titanium alloy and cooling the slag for crystallizingthe aluminum oxide and regulating the rate of cooling for forming comparatively small crystals. i

34. The process of removing the oxides of iron, silicon and titanium from bauxite, which comprises fusing it with magnetic iron pyrites and carbon and separating the sulfide-aluminum-oxide slag from the reduced iron-silicon-titanium alloy and Separatin out the pure aluminum oxide from the s ag.

35. The process of removing oxides of iron, silicon or titanium from ores containing aluminum oxide, which com rises form- 'ing a sulfide-aluminum-oxide s ag containing up to about 7 5 per cent of sulfide by fusing the ore with a metallic sulfide and carbon, the proportion of sulphide being such that a part of the aluminum oxide remains unconverted in the slag, and separating the sulfide-aluminum-oxide slag from the reduced iron, silicon or titanium.

36. The process of removing oxides of iron, silicon or titanium from ores contain- I ing aluminum oxide, which comprises forming a sulfide-aluminum-oxide slag containing up to about per cent of sulfide by fusing the ore with a metallic sulfide and carbon, the proportion of sulphide being such that a part of the aluminum oxide remains unconverted in the slag, separating the sulfidealuminum-oxide slag from the reduced iron, silicon or titanium and separating the aluminum oxide from the slag.

37. The process of removing iron, silicon and titanium from bauxite, which comprises forming a sulfide-aluminum-oxide slag containing up to about 75 per cent of sulfide by fusing bauxite with iron sulfide and carbon, the proportion of sulphide being such that a part of the aluminum oxide remains unconverted in the slag and separating the sulfide-aluminum-oxide slag from the reduced iron-silicon-titanium alloy.

38. The process of removing iron, silicon and titanium from bauxite, which comprises forming a sulfide-aluminumoxide slag containing up to about 75' percent of sulfide by fusing bauxite with iron sulfide and carbon, the proportion of sulphide being such that a part of the aluminum oxide remains unconverted in the slag, separating the sulfide-aluminum-oxide slag from the reduced iron-silicon-titanium alloy and separating the aluminum oxide from the slag.

39. The process of removing oxides of iron, silicon or titanium from ores contain ing aluminum oxide, which comprises forming a sulfide-a1uminum-oxide slag containing from about 10 up to about per cent of aluminum sulfide by fusing the ore with a metallic sulfide and carbon and separating the aluminum-sulfide-aluminum-oxide slag from the reduced iron, silicon or titanium.

40. The process of removing oxides of iron, silicon or titanium from ores containing aluminum oxide, which comprises forming a sulfide-aluminum-oxide slag containing from about 10 up to about 40 per cent of aluminum sulfide by fusing the ore with metallic sulfide and carbon and separating the aluminum-sulfide-aluminuin-oxide slag from the reduced iron, silicon or titanium and decomposing the aluminum sulfide and separating out the pure aluminum oxide.

41. The process of removing oxides of iron, silicon andtitanium from bauxite,

which comprises forming a sulfide-aluminum-oxide slag containing from about 10 up to about 40 per cent of aluminum sulfide by fusing bauxite with iron sulfide and carbon and separating the aluminum-sulfide-aluminum-oxide slag from the reduced iron-silicon-titanium alloy.

42. The process of removing oxides of .iron, silicon and titanium from bauxite,

which comprises forming a.sulfide-aluininum-oxide slag containing fromabout 10 up to about 40 per cent of aluminum sulfide by fusing bauxite with iron sulfide and carbon and separating the aluminum-sulfide-aluminum-oxide slag from the reduced iron-silicon-titanium alloy and decomposing the aluminum sulfide and separating out the pure aluminum oxide.

43. The process of removing oxides of iron, silicon or titanium from ores containing a difficultly reducible metal oxide which does not fuse below 194.0 (1., which comprises dissolving the difficultly reducible metal oxide in a sulfide-containing slag by fusing the ore with a reducing agent and materials yielding a sulfide separable through water, and treating the sulfide-refractory-oxide slag with water to separate the refractory oxide.

44. The process of treating ores containing a difiicultly reducible refractory oxide comprising removing oxides of iron, silicon or titanium by heating the ore with'rcduc-e ing agents and dissolving the refractory oxide in a sulfide decomposablethrough water, and treating the sulfide-refractoryoxide-slag with water for decomposing suiiide and scaarati'n the refractor' oxide agent and materials yielding a sulfide separable through Water, cooling the sulfidealuminum-oxide slag for crystallizing the aluminum oxide and treating the slag with water to separate the aluminum oxide.

46. The process of treating ores containing aluminum oxide comprising removing oxides of iron, silicon or titanium through reduction and dissolving aluminum oxide in a slag containing a sulfide decomposable by water and treating the slag with water to decompose sulfide.

47. The process of treating ores containing aluminum oxide comprising removing oxides of iron, silicon or titanium through reduction and dissolving aluminum oxide in a slag containing a sulfide decomposable by water, cooling the sulfide-aluminum-oxide slag to crystallize the aluminum oxide and thereupon decomposing the sulfide by treating the slag with water and separating the aluminum oxide from the decomposed sla 48. The process of removing oxides of iron, silicon and titanium from bauxite, which comprises forming a sulfide-alumr num-oxide slag containing aluminum sulfide by fusing bauxite with a sulfide having a heat of formation less than that of aluminum sulfide and a reducing agent, crystallizing the aluminum oxide by cooling the slag and decomposing aluminum sulfide by treating the slag with Water.

49. The process of removing oxides of iron, silicon and titanium from bauxite, which comprises forming a sulfide-aluminum-oxide slag containing aluminum sulfide by fusing bauxite with an iron sulfide and carbon, cooling the slag to crystallize the aluminum oxide, decomposing the aluminum sulfide by treating the slag with water and thereupon separating formed aluminum hydrate from the crystallized aluminum oxide.

sulfide by treating the slag with Water.

51. The process of treating bauxite, which comprises removing oxides of iron, silicon and titanium and forming a sulfide-aluminuin-oxide slag containing from about 10 up 5 to about 40 per cent of aluminum sulfide by fusing bauxite with an iron sulfide and carbon, crystallizing aluminum oxide by cooling the slag, thereupon decomposing aluminum sulfide in the slag with water and separating formed aluminum hydrate from 10' crystallized aluminum oxide.

In testimony whereof I have hereunto affixed my signature.

TURE ROBERT HAGLUND.