US1094371A - Process of extracting metals from ores. - Google Patents

Description

H. S. MAOKAY. PROCESS. FOR EXTRAGTING METALS PROM ORES. APPLICATION FILED APR.16, 1913.

1,094,371 Patented Apr. 21, 1914.

MM 5] W00 Wcoz %1 (meme UNITED STATES PATENT OFFICE.

HENRY S. MACKAY, OF NORWICH, CONNECTICUT, ASSIGNOR T0 MACKAY PROCESS COMPANY, OF NORWICH, CONNECTICUT, A CORPORATION OF DELAWARE.

Specification of Letters Patent.

Patented Apr. 21, 1914.

Application filed April 16, 1913. Serial N 0. 761,565.

To all whom it may concern Be it known that I, HENRY S. MAoKAY.

a citizen of the United States, and a resident of Norwich, Connecticut, have invented a new and useful Improvement in Processes for Extracting Metals from Ores, of which the following is a specification.

My-invention relates to processes for extracting metals from ores and, particularly, for extracting metals from ores carrying a small ercentage of the desired metal.

It a so relates to the method of producing a solvent for extracting metals from ores from the elements contained in the ores with the addition of water.

The object of the invention is to provide a method of extracting metals from ores wherein a solvent is made and maintained from the elements of the ore in the operation of the process.

A further object is to provide a process wherein the solvent will extract the desired metal from the ore and one which will be regenerated immediately upon removal of the desired metal from the solution; and wherein the metal deposited will be pure metal of commerce and require no refinement outside of the process.

"There are for commercial reasons only two solvents that can be used; one is sulfuric acid and the other is hydrochloric acid. In order to successfully extract and refine metal directly from ores it is necessary that the solvent be produced from the'elements of the ore and in the operation of the process. Not only is this necessary but also a solvent must be produced which will extract the metals, and one which will be regenerated up on the depositing of the metals from the solution. The desired metal deposited from the solution must be the pure metal of commerce. The process must be so conducted that the solution used as an electrolyte will remainaspure as possible and contain no injurious. elements, and that the solvent formed will be of such a character a that it will not-react wh-ile the desired metal To form a solvent or to refine the desired metal outside of the process adds so greatly to the expense as to make a lixiviation process commercially impracticable. A solvent to be most efficient must be a weak solution of an acid in order that it may be formed and maintained out of the elements of the ore. A weak solution of the acid takes up less impurities than a strong solution and it is ust as good a solvent if the ore is properly prepared. There is a less loss of acid in' the mechanical operation ofthe process, such as in replacing the solution carrying acid from the ore, after extraction of the desired metal from the ore. By using a weak solution of acid it can be maintained in the process in the lixiviation of ores carrying a very low percentage of sulfur.

The process is especially advantageous in the extraction of copper from ores; In the process sulfate of copper is formed. It may be formed by roasting the ore. If desired, and if the ore does not contain a suflicient amount of sulfur, sulfur may be added and then roasted. The sulfur may be in any form, such as in sulfid ores or compounds, or pure sulfur, the object being to roast the ore in the presence of sulfur, whether the sulfur be present in the ore or added thereto. WVhe n the ores are roasted, sulfates and oxide of the metals contained therein are produced, and also insoluble compounds of the undesired elements of the ore, such as, ferric oxid, calcium sulfate, are formed. Part of the desired metal may be extracted by the addition of Water, forming thereby a solution ofthe sulfates of the desired metal of the ore. This solution then is conveyed to an electrolytic vat where a part of the desired metal will be deposited and an active solvent will be formed in the presence of the sulfate of the desired metal.

Sulfuric acid may be formed in the solution or hydrochloric acid may be formed and used as the solvent. If is it desired to form sulfuric acid in the solution during the electrolysis, sulfate of the copper of the ore will be decomposed, whereupon the'copper of the ore will be deposited on the cathode plates and sulfuric acid will be formed in the solution On the other hand, if it is desired to form hydrochloric acid, sodium chlorid is injected into the process'at any desired point, and by substitution, sodium sulfate and hydrochloric acid or chlorid of the metals are formed. When the solution carrying the chlorid of the copper is electrolized, the copper chlorid is decomposed as before and copper is deposited on the cathodes and hydrochloric acid is fomed in the solution. Whether sulfuric acid or hydrochloric acid is formed in the solution contained in the electrolytic vats, the solution is continuously applied to the ore and the ore is thoroughly leached therewith, removing the copper sulfate and the copper oxid or the copper chlorid which still remained after leaching with water. This solution is continuously conducted to an electrolytic vat Where the copper is de causes the formation of sulfates and oxids of the metals. This requires very little asulfur as the sulfur compounds immediately break up to form the sulfates, while oxids of some of the metals are formed. All that is required is enough to form sulfates of part ofthe copper sufficient to maintain the solvent formed by the electrolysis of the solution. Sulfur in any form is used and in any quantity but preferably enough to secure about one part of sulfur to two of copper or even as low as one part of sulfur to four of copper. This proportion may be varied according to the character of the ore treated. Itdepends on the base elements in the ore to be neutralized. If it has considerable calcium more sulfur is used. If the orecarries a large amount of sulfur the excess of sulfur is driven off until the iron is oxidized to an insoluble compound and the copper is converted, to a soluble compound, such as CuSO, and CuO. I

In carrying out the process the ore is roasted at a low temperature in the presence of sulfur, the sulfur being added if not present. The roast is then directed into a receptacle for cooling, if desired, and is then conveyed or directed into a leaching vat where it is treated with water. This extracts the soluble sulfates of the copper which are taken up by the solu tion. The solution is conveyed to an electrolytic tank where a (part of the copper sulfate isdecompose the copper is deposited and sulfuric acid Will be formed in the solution. The solution containing sulfuric acid and copper sulfate is used for leaching out the balance of the copper in the roasted ores existing in the form of copper oxid or sub-sulfate. This operation is continued until the solution is built up to a standard and contains copper sulfate, sulfuric acid and aluminum sulfate, if aluminum is in the ore. It is found that the best solution for extracting copper from ores carrying a low percentage of copper and sulfur should carry about 2% sulfuric acid and 2% copper in the form of copper sulfate. These percentages are varied in accordance with the amount of sulfur carried by the ore so as to form a solvent that can be maintained from the elements of the ore in the process. When the standard solution is formed, in the further continuance of the process, the ore is so roasted that the sulfur content is varied to maintain this standard solution, and without taking up the base or undesired elements of the ore which fouls the solution when used as an electroyte. The special advantage to be obtained by this process is to produce and maintain a good solvent and a good electrolyte to enable the precipitation of the copper from the electroyte as pure electrolytic copper and maintain a substantially uniform electrolytic condition of the electrolyte. If it is desired to have a comparatively large percentage of acid in the solution, it may be producedeither by'roasting the ore so that a large per centage of sulfate is formed, or by increasing the amount of sulfur in the mixture. This may be done by varying the degree of temperature in the furnace. A low temperature not to exceed 600 degrees centigrade and the proper amount of oxygen, will form sulfates of copper and oxids'of iron. If too much sulfate is formed, by increasing the temperature above 600 degrees Centigrade, some of the sulfates are decomposed and more oxids of copper are formed which in turnwill. consume acid in the solution. If there is an excess of sulfuric acid the temperature may be raised so as to form oxids of the metals of the ore until the strength of the sulfuric acid is reduced. In this way the solvent may be maintainedin a most efiicient condition. The acid formed in the solution will thus be balanced with the -Work it is required to dov aluminum. The aluminum sulfate immediately upon addition of the Water forms an 'arno Al2(SO4)3 scuo.=scuso AI2(OH).

A greater amount of copper is thus removed from the ore in the form of copper sulfate, upon the addition of water, than if no aluminum sulfate was in the ore 'orin the roasted mixture. Upon electrolysis acid will attack copper oxid, formingcopper sulfate. If the sulfuric acid should be completely used up the aluminum sulfate will in, turn attack the copper oxid as before. This may be continued until all the copper oxid is removed, whereupon the aluminum sulfate will be carried into the vat with the copper sulfate and upon electrolysis sulfuric acid is formed by the decomposition of the copper sulfate and the solvent will contain sulfuric acid and aluminum sulfate.

If it is desired that chlorids be formed from the sulfates of the metals and hydrochloric acid produced instead of sulfuric acid in the solution, it may be done by adding sodium chlorid at various stages in the process, such as before the roast, to the sulfate solution, or before electrolysis. After electrolysis of the solution containing chlori'ds, hydrochloric acid will be formed and this solution added to the ore acts upon the copper oxid and forms eupric chlorid and on the aluminum hydroxid and forms aluminum chlorid:

' 21101 cuo=cue1 H2O. J

31101 AI (0H) a- -srr,o Alon.

ango 2 1c1 scuo=acuc12 2A1 on The solution of cupric chlorid thus formed is then directed to the'electrolytic vat and electrolyzed, forming h'ydrochlorid acid. This when applied to the ore takes up copper oXid and the aluminum hydroxid as before. This is repeated until all the copper oxid is removed and then the hydrochloric acid forms aluminum chlorid with the aluminum hydroxid. i v o It is desirable that the solution should at all times contain some copper sulfate when sulfuric acid is used as solvent or some cupric chlorid when hydrochloric acid is used as a solvent, since the presence of the copper salt in the solution produces a good conductive electrolyte and at the same time it is a source from which sulfuric acid or hydrochloric acid may be formed.

The invention may be used in connection with many processes and such processes may be greatly varied bythose ski-lied in the art without departing from the spirit of the invention.

-*In'-{t-he' .drawing is shown an apparatus or systemywherein one of the many processes covered by the claims and which involve the use of my invention,- may be conducted.

The ore tobe treated is delivered to the furnacel by a chute 2. The furnace may be of any suitable type but I have shown here a furnace of a well known type which is provided with a central rotatable shaft 7 having rakers S for constantly turning the ore and shifting it. through its various compartments 9 While it is undergoing aroast. The rakers 8 rake the ore from the top of the furnace where the ore is delivered from the chute 2 to and through the compartments of the furnace in succession. During the roast the ore is kept at a proper temperature and a suitable amount of air is admitted for the proper length of time to produce the desired proportion of the sulfate to the oxids of the metals. This treatment may be varied according to the character of'the ores as heretofore described.

The ore is finally delivered through the chute 10 into a receptacle 4. The bottom of the receptacle 4 is hopper shaped and is provided with a gate 5 which delivers the ore to a belt conveyer 6. The conveyer carries suitable amounts of the ore to a leaching vat 15. In starting theprocess water is then drawn through the pipe 14 and directed into the leaching vat 15. When it passes through the roasted ore, it leaches out the soluble sulfates forming a solution thereof. The vat 15 is provided with a filter bottom 16 which will allow the liquid to pass into the compartment 17 which is thus formed between the filter 16 and the bottom of the vat. The liquid from the ore is directed through a valve and pipe 18 into a container 19.

lVhile the solution is in the container 19, it may be heated by steam which is allowed to enter through the valve and pipe 20. lVhen suitably heated, preferably to about 50 degrees centigrade, it is allowed to flow through the valve 21 into the electrolytic tank 22 where the current from the source 25 causes the deco nposition'of a part of the copper sulfate and thefc-rmation of sulfuric acid in the solution. The desired metal is removed from the solution as metallic plate. At the same time that the copper is separated from the solution, the sulfion with which it is combined is liberated at the anodes and there decomposes water and forms sulfuric acid. The cupric sulfate left in the solution forms a good conductor in the electrolyte and also forms a source of.

. sulfuric acid that may be drawn .upon by running the current a little longer. The solution is then collected in the receptacle 23. The plates may be removed and the copper deposited thereon may be melted into bars in any form desired for commercial uses.

The-acid solution is pumped through the pipe 26 by means of the pump 27 to the container 11. The solution from the electrolytic vat 22 is circulated continuously through the vats and containers 23, ll, 15, p

19 and the vat and the copper is precipitated 1n vat 22 while the acid is recovered and part of the copper sulfate of the solution is carried back to the leaching tank 15 where the acid takes up the copper in the ore. When all of the copper has been removed from the ore, the solution may be removed from the tailings by adding water equal to the Weight of the solution in the tailings which replaces the solution as the solution filters down through the ore, the Water being left behind in the ore. The tailings of the ore are removed through the gate 28.

If sodium chlorid is added to the solution, the sulfates contained in the ore are chan ed to the chlorids in the leaching vat 15 an a solution containing cupric chlorid and sodium sulfate is formed. This is conducted to the electrolytic vat 22. Upon electrolysis of the solution, the copper is deposited upon the copper plates and the chlorin acts upon the water to form hydrochloric acid in the solution. The solution is then conducted to the container 23. From the receptacle 23, it is conducted through the vat 11 to the leaching vat 15, where the solvent will attack the copper still remaining in the ore. If any copper sulfate still remains, the sodium chlorid remaining in the solution will form cupric chlorid and sodium sulfate and the hydrochloric acid. will act upon copper oxid and form cupric chlorid. A solution of cupric chlorid is thus formeda second time. This is taken from the ore and again directed through the vat 19 to the electrolytic vat 22, where hydrochloric acid is again formed. The process is continuously carried out as before and the steps are exactly the same as When thesulfuric acid is used as a solvent.

If excess of sodium chlorid is added to thesulfate solution, a small amount of sodium chlorid will remain in the solution after electrolysis. If just enough is added to take up the sulfates, hydrochloric acid alone will be produced in the electrolytic vat. If a less amount of sodium chlorid is added to the solution and so that there will still remain some of the sulfates, hydrochloric acid and sulfuric acid Will be formed in the electrolysis if continued.

If the ore contains aluminum, copper sulfate and aluminum sulfate will be formed in the roast. The roasted ore is then conveyed to the leaching vat 15 and water is directed through the pipe 14 on to the ore. The copper sulfate and the aluminum sulfate are leached out of the ore. The aluminum sulfate upon the addition of the water is dissolved and attacks the-cupric oxid and forms copper sulfate, so that an additional amount of copper sulfate is leached out of the ore. The solution is then conveyed to the electrolytic tank 22, where the copper sulfate is decomposed, the copper being deposited on the cathodes and sulfuric acid being formed in the solution. The solution is then collected in the receptacle 23 and raised to the container 11, from which it is drawn and directed upon the ore. The sulfuric acid Will attack any copper oxid remaining in the ore and form aluminum sulfate by action upon the aluminum hydroxid that may remain. When all of the sulfuric acid is used up the solution. Will contain aluminum sulfate which may be directed upon the ore.

If sodium chlorid is added to the solution before the electrolysis, the copper sulfate in the solution is changed to' cupric chlorid and hydrochloric acid is formed in the electrolytic vat. W hen the solution from the vat is directed upon the ore, the hydrochloric acid attacks the copper oxid to form cupric chlorid and attacks the aluminum hydroxid formed by the addition of water in the preceding leach, and forms aluminum chlorid. The aluminum chlorid acts with the activity of hydrochloric acid and forms an additional amount of cupric chlorid by its action upon any copper oXid that may remain in the ore. A solution of cupric chlorid is thus drawn from the leach and directed to the electrolytic vat where hydrochloric acid is again formed. The hydrochloric acid solution is again directed upon the ore and if all of the copper oxid is removed from the ore,

aluminum chlorid may be formed from any ammonium hydroxid remaining in the ore which may be directed upon a new charge of ore.

What I claim as new and desire to secure by Letters Patent is as follows:

1. The process of extracting metals from ore containing sulfur which consists in pro ducing from the elements of the ore a solvent for the metal, electrolyzing the solution to extract the metal and, during the process,

continuoi'lsly treating the ore so as to produce and maintain a high efficiency of the solvent and electrolyte.

2. The process of extracting metals from ores which consists in producing from the elements of the ore in the presence of sulfur a solvent for the metal, electrolyzing the solution toextract the metal and, during the process, continuously treating the ore so as to produce and maintain a high efficiency of the solvent and electrolyte.

3. In a process for extracting metals from ore the steps which consist in roasting the ore in the presence of sulfur, leaching and electrolyzing, and controlling the composition of the solvent by the character of the roast.

4-. A process for extracting metals from 5. A process for extracting metals from ore which consists in forming a solvent for ores from the elements of the ore, by roasting the ore, leaching and electrolyzing, and controlling the composition of the solvent and the electrolyte by the character of the roast.

6. A process for extracting metals from ores, which consists in forming a solvent from the elements of the ore by roasting charges of the ore in the presence of a small amount of sulfur, leaching the roasted ore and electrolyzing the leach, the roast being modified according to the character of the solvent desired. v

7. A process for extracting metals from ore, which consists in roasting charges of the ore in the presence of sulfur so as to pro duce a desired proportion of the sulfates to the oxids of the metals of the ore, leaching and electrolyzing and'varying the solvent according to the manner in which the charges of ore are roasted.

8. A process for extracting metals from ore, which consists in roasting the ore in the presence of sulfurso as to produce and maintain a desired proportion of the sulfate to the oxids of the metals of the ore, so that the resultant solvent will dissolve the desired metal of the ore leaving the undesired salts and bases in the ore, leaching and electrolyzmg.

- 9. A process for extracting metals from ores, which consists in roasting the ore in the presence of sulfur,'forming an insoluble compound with the undesired elements of the ore and soluble compounds with the desired metals of the ore, leaching and electrolyzing, the charges being leached by the solution produced by electrolysis.

10. A process for extracting metals from ores, which consists in roasting the ore in the presence of sulfur and forming insoluble sulfates and oxids of the undesired'elements of the ore and soluble sulfates and oxids of the desired metal of the ore, leaching and electrolyzing, the charges of the ore being leached by the solution produced by the electrolysis.

11. Aprocess of extracting metals from ore which consists in forming sulfates of the desired metal of the ore by roasting the ore in thepresence of sulfur, leaching the ore and electrolyzing until the solvent hasreached a desired character and degree of strength, modifying the roast so as to produce oxids and sullicient sulfates to keep the solvent at the desired strength and character, leaching and electrolyzing the solutions drawn from the ore and directing the solution produced by electrolysis each time upon the roasted charges of the ore.

12. A process for extracting metals from ores, which consists in treating the ore, leaching the ore with asolvent, electrolyzing the solution to deposit the desired metal of the ore and to regenerate the solvent in the solution from the elements contained in the solution, regulating the solvent and the elec trolyte by the said treatment of the ore and continuously leaching and electrolyzing and regenerating the solvent and depositing the metal. 1

13. A process for extracting copper from ore, which consists in roasting the ore in the presence of a small amount of sulfur compared to the amount of copper, leaching the ore and electrolyzing.

14. A process for extracting copper from ore, which consists in roasting the ore in the presence of sulfur, the said sulfur being less in amount than the copper contained in the ore, leaching the ore and electrolyzing.

15. A process of extracting metals from ore, which consists in leaching the ore with a solution containing about 2% sulfuric acid 4 and electrolyzing the solution.

16. A process of extracting copper from ores, which consists in roasting the ore in the presence of about one part of sulfur to four parts of copper to about two parts of sulfur to four parts of copper, leaching charges of the ore and electrolyzing the solution and again leaching the ore and electrolyzing, and so on continuously.

17. A process for extracting metals from ores, which consists in roasting the charges of the ore in the presence of a small amount of sulfur in such a way that the desired elements may be extracted with a weak solution of sulfuric acid and a weak solution of sulfuric acid may be formed and maintained in a solution from elements in the ore by leaching the roasted ore and electrolyzmg.

.18. A process for extracting metals from ore, which consists in roasting charges of the ore in the presence of a small amount of sulfur, leaching with a solution and elec trolyzing to produce a weak solution .of sulfuric acid, the roasting being such that the solution of sulfuric acid may be maintained insubsequent leaching of the chambers of the ore and electrolysis of the solution.

19. A process of extracting copper from ores which consists in roasting the ore in the presence of a small amount of sulfur forming copper sulfate, leaching) with a solution and electrolyzing to decompose a part of the copper sulfate, continuously leaching the roasted ore with the solution produced by electrolysis, and keeping a part of the copper sulfate in the solution.

20. A process of extracting copper from ores containing sulfur-and aluminum, which consists in roasting the ore so as to form sulfates and oxids of the desired metals of the ore, leaching with water and electrolyzing lyzing the solution produced by leaching, and continuously leaching with the solution produced by electrolysis.

21. A process for extracting metals from ore which consists in roasting the ore in the presence of sulfur so as to form sulfates and oxids of the metals of the ore, leaching the ore and electolyzing the solution, the roast being such that the sulfates and oxids of the metals of the ore will be in such proportions that when the solution is electrolyzed a desired amount of the active agent will be produced in the solution without injurious impurities. Y

22. A process for extracting metals from ores, which consists in roasting charges of the ore in the presence of a small amount of sulfur and so as to produce soluble compounds of the desired metals of the ore and insoluble compounds of the undesired metals of the ore and so that upon continuous leaching and electrolyzing a weak solution of sulfuric acid and a good electrolyte will be formed and maintained, leaching the roasted ore, electrolyzing, and so on continuously leaching and electrolyzing until the desired metal is extracted.

23. The process of extracting copper from ore containing iron, which consists in roasting the ore in the presence of sulfur in such a way as to form sulfate and oxid of copper and insoluble oxid of iron, leaching and electrolyzing, the ore being continuously leached with the solution produced by the electrolysis.

24. In a process of extracting copper from ores containing aluminum, the steps which consist in forming a solvent from the elements of the ore by roasting the ore so as to produce sulfates of aluminum and copper and adding water.

25. A process of extracting metals from ore containing aluminum, which consists in forming a solvent from the elements of the ore by roasting the ore in the presence of sulfur so as to produce the sulfates of the metals, leaching With a solution of sodium chlorid and electrolyzing the solution.

26. A process of extracting copper from ore having aluminum, which consists in roasting the ore in the presence of sulfur, forming copper sulfate and aluminum sulfate, leaching the roasted ore and electrolyzing to decompose part of the copper sulfate, continuously leaching the roasted ore with the solution produced by the electrolysis and continuously keeping copper sulfate and aluminum sulfate in the solution.

27. A process for extracting metals from ore, which consists in producing a solvent for the ore from the elements of the ore by roasting the ore in the presence of sulfur so as to produce a desired proportion of the sulfates to the oxids of the ore, leaching with water, adding sodium chlorid to the leach, electrolyzing and forming hydro chloric acid.

28. A process for extracting metals from ore, which consists in roasting the ore in the presence of a small amount of sulfur and forming sulfates of the metals of the ore, adding sodium chlorid solution to change a part of the sulfates to the chlorids, electrolyzing the solution so as to form hydrochloric acid and sulfuric acid.

29. A process of electro-chemically producing refined copper from copper ore, which consists in forming a solvent from the elements of the ore in the presence of sulfur, maintaining the character of the solvent and the elctrolyte by treating the ore without introducing any chemicals from an outside source, and electrolyzing the said electrolyte.

30. A process for extracting metals from ore, which consists in treating charges of the ore so as to form and govern an active solvent with which the ore is treated and regulating by the treatment of the ore the salts and bases formed in the solution from which the metal is extracted and electrolyzing the solution to precipitate the metal and regenerate the solvent.

31. A process of extracting metals from .ore, which consists in roasting crushed ore, leaching the ore, electrolyzing the solution with which the ore is leached thereby obtaining refined metal, the character of the solvent and the electrolyte being formed, maintained and controlledby the roasting and leaching of the ore, and the solvent being regenerated by the electrolysis.

/ In testimony whereof, I have signedmy name to this specification in the presence of two subscribing witnesses.

HENRY S. MAGKAY.

Witnesses FRANK F. CRAMPTON, MILTON W. SAMETZ.

Images