US1305787A

US1305787A - febotsow

Info

Publication number: US1305787A
Authority: US
Publication date: 1919-06-03
Anticipated expiration: 1936-06-03

Description

COMPANY, OF 1 FFICE.

C. FERGUSON, OF GARDEN CITY, NEW YORK, ASSIGNOR TO NICHOLS COPPER YORK, N. Y., A CORPORATION OF NEW YORK. l J'ATMENT OF ELECTROLYTIC SLIMES.

nearer, I no Drawing." Application filed September 29,

T all whom it may concern of Garden City, Nassau county, New York, 4

have invented certain new and useful Imrovements in the Treatment of Electrolytic glimes, of which the following 1s a specification.

My invention relates particularly to the treatment of slimesjsuch asthose obtained in the electrolytic refining of metals, as, for

instance, copper, though it maybe applied to others, such as those obtained 1n the manufacture of blue vitriol and similar slimes or muds. These slimes generally contain gold, sillver, cop er selenium, tellurium, arsenic, antimony, lead and silica in varying proportions and sometimes contain also traces of bismuth, nickel and iron.

The particular slime, to which the process is particularly applicable, is that resulting from the electrolytic refining of crude metallic copper, that is to say, bessemeriaed copper matte. A typical analysis of this material (in the dry state) is as follows:

Copper 27.47% Silver 16.97 Gold .39 Selenium and tellurium 10.40 Arsenic 1.72 Antimony .44 Silica 25.

' Lead sulfate 2 Bismuth, nickel, iron, etc Traces In this sample, the copper was mostly in the form of metallic copper, the silver was mostly 'tellurid andv selenid, and the gold 4 principally tellurid.

The object of my invention is to so treat slimes of the kind specified that the values, gold, silver and copper are extracted in a commerciall practicable and economical manner. ore 'articularly T aim to produce fromthe-slimes, pure gold and silver and copper sulfate, (or metallic copper if Speciflcation of Letters latent.

Patented June 3, 1919.

1915, Serial No. 53,178. Renewed October 26, 1918. Serial Ho. 259,352.

ployed, possessing many valuable advantages thereover, and comprising the following steps First, roasting the slime in the presence of a sulfatizin agent to the point where substantially all of the silver is converted into sulfate, and a part of the copper remains in the form of sulfate, and another part remains in the form of oxid. During this operation a considerable part of selenium, tellurium, arsenic, lead and bismuth are volatilized from the slime. During this step the losses of precious metal values are extremely small.

Secondly, lixiviating or leaching with a suitable solvent for certain portions of the roasted slime (particularly the silver sulfate and copper sulfate) and thereafter extracting by suitable methods, the metal values contained in the leached residue.

When treating a slime or mud of the kind 1above described I preferably proceed as folows:

The mud is roasted at a suitable roasting temperature preferably at a temperature of from 500 C. to 600 C. in the presence of a sulfatizing agent such as sulfuric acid or a sulfate, such as copper sulfate or iron sulfate. The sulfatizing agent is employed in sulficient amount to sulfatize not merely the copper, but also the silver. The roasting is carried out in the presence of air, so that instead of the above compounds containing the sulfuric acid radical, any other compound such as sulfur dioxid or trioxid or a sulfid, as pyrites, which under the conditions will produce a compound containing such radical and will effect a sulfatizi action, may be used as sulfatilzing agent. lhe roasting operation is designed to produce a substantially complete oxidation of the mud, and this may require a roasting period of about hours. The roasting is so carried out, preferably, that substantially all of the silver is transformed into silver sulfate, the copper being partly in the form of oxid and partly in the form of sulfate.

- During the roastin operation the whole, or usually, a part of t e selenium, tellurium and arsenic goes 0]? in gaseous form. The roasted slime is now lixiviated preferably with water by which almostall of the silver together with a part of the copper and. possibly traces of selenium,tellurium, arsenic and antimony are separated in soluble form from the solid residue containing the other waterinsoluble constituents.

The thus produced silver solution which may contain 94% of the silver and 20 to of the copper of the original slime may be treated in any known manner for the separation and removal of the silver and copper, that is, for the extraction of the metal values therein. For example, it may be treated so as to produce silver precipitated on copper in the form of silver cement.

The solid residue, above mentioned, resulting from the lixiviation with Water 1s now lixiviated with a dilute acid, such as sulfuric acid, whereby there is produced a second solid residue containing the acid insoluble constituents and a solution which contains substantially all of the copper content of the first solid residue, a very small percentage of silver and possibly some selenium, tellurium, arsenic and antimony.

This second solution, which may contain to 25% of the copper and 3% of the silver of the original slime and may be termed the copper solution, may be treated in any suitable manner for the extraction of its values. For example it may be treated to form cement silver and the co per sulfate solution made into blue vitriol: or electrolyzed to form electrolytic copper or passed over iron to form cement copper.

The second solid residue resulting from the acid treatment, containing all of the gold of the original mud and substantially no copper, may be subjected to any suitable treatment for the extraction of the gold. Preferably the goldis dissolved out by any gold solvent, in which case it is advantageous to use chlorin or a chlorin compound, such as aqua regia, which may be made from sulfuric acid, sodium nitrate and sodium chlorid. Bythis treatment practically all of the gold is obtained in the soluble form of gold chlorid. The gold solution may be treated, if desired, with a-reducing agent, such as eopperas or ferrous sulfate, or sulfur dioXid, to precipitate the gold in the form of metal which may be refined by conventional methods. The residue resulting from the a ua regia treatment, which may be termed t e third residue, contains small percentages of silver and gold, for example 2 to 3% of the silver of the original mud, mostly in the form of chlorid, and .75% of the original gold, and is treated. with a solvent for silver, preferably sodium hyposulfite; this dissolves practically all of the silver and a little of the gold. The silver and gold are now recovered from the hyposulfite solution in any known way. The final residue resulting from the hyposulfite treatment is available for use in ore smelting or metal refining furnaces.

Instead of lixiviating first with Water and then with acid, as described above, it may be advantageous in some cases, especially- When the selenium, tellurium, arsenic and antimony contents of the original slime are relatively small, to omit the water lixivia- 'tion and employ only the acid lixiviation.

In this case the silver and copper are obtained as sulfates in the solution, and the solid residue is similar to the second solid residue above described. In either case the original mud or slime is roasted with a sulfatizing agent, and then lixiviated with a solvent ,for certain of the ingredients of the sulfatized product.

The temperatures and the strengths of the various solutions and the time of treatment will, of-course, vary. with the different requirements, but such details of operation are well within the province of anyone skilled in the art. If no gold were present in the original mud the stage of the process dealing with gold would, of course, be omitted. If the second residue is substantially free from silver and copper, the chlorin treatment might be omitted and the residue subjected to refining merely.

I claim:

1. The herein described process of treating electrolytic copper refinery slimes containing silver, but not containing material quantities of sulfur which comprises roasting the same in the presence of an added sulfatizing agent, until at least the major part of the silver is converted to silver sulfate, and thereafter leaching the roasted material.

2. The herein described process of treating the slimes produced in the electrolytic refining of metallic copper, which slimes consist essentially of copper, silver, gold, se-

lenium, tellurium, arsenic, antimony, silica and lead sulfate, together with traces of hismuth, nickel, iron and the like, which slimes do not contain any considerable quantities of sulfur, which comprises subjecting the said slimes, in thepresence of an added sul-' fatizing agent to a roasting operation, and thereafter leaching whereby the bulk of the silver present is obtained in the solution and whereby substantially all of the gold is left in the undissolved residue.

3. The herein described process of treating slimes containing gold, silver and copper, which comprises subjecting such slime to a roasting operation in the presence of a sulfatizing agent, whereby a silver and a part of the copper are converted into sulfates, separating the silver and copper from the gold-bearing residue by leaching the roasted material with a solvent for the silver and copper, recovering the silver and copper from the solution thereof, and recovering the gold from the gold-bearing residue.

4. The herein described process of treating slimes which comprises subjecting slime to a roasting operation in the presence of a sulfatizing agent, treating the roasted slime with water to produce water-soluble and Water-insoluble portions, extracting the metal values from said water-soluble portion, treating said Water-insoluble portion .With an acid to produce acid-soluble and acid-insoluble portions, and extracting the metal values from said acid-soluble and acid-insoluble portions.

5. The herein described process of treatingslimes which comprises subjecting slime to a roasting operation in the presence of a sulfatizing agent, treating the roasted slime With Water to produce Water-soluble and Water-insoluble portions, extracting the metal values from said water-soluble portion, treating said water-insoluble portion with sulfuric acid to produce acid-soluble and acid-insoluble portions, and extracting the metal values from said acid-soluble and acid-insoluble portions.

6. The herein described process of treating slimes which comprises-subjecting slime to a roasting operation in the presence of a sulfatizing agent, treating the roasted slime with water to produce water-soluble and Water-insoluble portions, extracting the metal values from said water-soluble portion, treating said water-insoluble portion with an acid to produce acid-soluble and acid-insoluble portions, extracting the metal values from said acid-soluble portion, treating said acid-insoluble portion with a solvent for gold to produce a gold containing solution and an insoluble residue, and extracting the metal values from said solution and said residue.

7. The herein described process of treat-' ing slimes containing gold, silver and copper, which comprises subjecting such slime to a roasting operation in the presence of a sulfatizing agent, treating the roasted slime with a solvent for substantially all of the silver and copper in the roasted slime whereby a soluble portion containing silver and copper and an insoluble portion containing the gold are produced, and extracting the metal values from said soluble and insoluble portions.

8. The herein described process of treating slimes containing gold, silver and copper, which comprises subjecting such slime to a roasting operation in the presence of a sulfatizing agent, treating the roasted slime with Water, whereby a water-soluble portion containing part of the silver and copper and a water-insoluble portion containing the gold are produced, treating said Water-insoluble portion with sulfuric acid whereby an acid-soluble portion containing substantially the Whole of the silver and copper of said water-insoluble portion and an acid-insoluble portion containing the gold are produced, and extracting the metal values from said waterand acid-soluble portions and from said acid-insoluble portion.

9. The herein described process of treating slimes containing gold, silver and copper, which comprises subjecting such slime to. a roasting operation in the presence of a sulfatizing agent, treating the roasted slime with water, whereby a water soluble portion containing part of the silver and copper and a water-insoluble portion containing the gold are produced, treating said Water-insoluble portion with sulfuric acid, whereby an acid-soluble portion containing substantially the whole of the silver and copper of said water-insoluble portion and an acid-insoluble portion containing the gold are produced, extracting the metal values from said Waterand acid-soluble portions, treating said acid-insoluble portion with a gold solvent to produce a gold containing solution and an insoluble residue, and extracting the metal values from said solution and said residue. x

10. The herein described process of treat ing slimes produced in the electrolytic refining of metal which comprises roasting the same in the presence of an added sulfatizing agent until sulfates of the metal have been formed in substantial quantities. In testimony whereof I have hereunto set WILLIAM C. FERGUSON.

' my hand.