US1011900A - Metallurgy of metal sulfids. - Google Patents

Description

E. A. ASHCROFT.

METALLURGY 0F METAL SULFIDS. APPLICATION FILED APR. 9, 1910.

1,01 1,900. Patented Dec.19,1911.

' perfectly recovered EDGAR ARTHUR ASHCROFT, 0F SOGN, NOB-WAY.

METALLUBGY OF METAL SULFIDS.

Specification of Letters fatent.

Patented Dec. 19, 1911.

Application filed April 9, 1910. Serial No. 554,511.

To all whom 'it may concern:

Be it known that I, EDGAR ARTHUR ASH- CROFT, subject of the King of England, residing at Sogn, Norway, have invented certain new and useful Improvements in the Metallurgy of Metal Sulfids, of which the following is a specification.

This invention relates to improvements in the metallurgy of metal sulfids.

Sulfids of metals nearly free from gangue are produced in large quantities from the mechanical concentration of the well known Broken Hill refractory ores which are taken here as sufficiently illustrative of similar ores which occur with slight modifications all over the world and are the treatment herein described.

Two leading products from the concentrating mills are recognized in the arts today, viz: (A) zinc concentrates containing upward of 40% zinc and under 12% lead .and some silver, and (B) lead concentrates of lead and un- Also in containing upward of 50% der 12% of zinc and some silver. smaller quantities. ucts such as slimes and middlings of varying composition. In treating the proccss of zinc smelting in retort furnaces is the one generally employed and the leadv and silver and sulfur are either lost or very imfrom the residue at great expense. (B) the process of lead smelting is nowalmost universally employed and the zinc and sulfur are lost. The intermediate products C) are at present only capable of economica treatment by mixing with other ores in smelting furnaces in trifling quantities or by being first converted by mechanical separation int? products resembling .either (A) or (B) in composition.

The present invention has for its princi al object the more economical treatment 0 the zinc sulfid residues left after the treatment of the products A. and B. according to the method described in my U. S. applications Serial No. 554,508, filed April 9th, 1910, and Serial lie-551,509, filed April 9th, 1910. But either of the roducts A. B. or G. or any other metal sul (1 may also be treated without departing from this invention, it being self evident that if separate metals are desired the sulfids must be separated. According to British Patent No. 10829/ 1897 J. Swinburne has suggested the treatment of such products or the original ore from whence they are derived by eleclikewise amenable to (C) intermediate proding ing the iron is however trolyze the melt receiving the iron first into by obtained. metal being deposited from a mixed chlorid trolyzing sulfids in a bath of fused chlorids and gettingofi sulfur and-metals. This reaction however requires a high temperature (about 600700 C.) and very violent agitation of the melt to prevent settling and has never been carried out in practice.

I have discovered that a more practical and convenient process for the above purpose is to so electrolyze the melt as to get off one or other of the chlorids of sulfur and metals according to one of the following reactions which will take place if the electrolysis is conducted at or about the respectively stated temperatures.

1 MS+2MO1,=3M+SC1, Temp. 350C. 2 Ms+ Mo1,=2M+so1, 450 0. a 2MS+ Mo1,:3M+s,o1, 550C.

The sulfur chlorid given ofi may be readily condensed, (assisted in the case of the less stable products of reactions 1 and 2 by artificial cooling) and afterward reacted with metal sulfids as described in Swinburne and Ashcrofts U. S. Patent No. 691,822, dated January 28th, 1902 producsulfur and metal chlorids the latter being added to the electrolysis bath to compensate for the chlorids decomposed by the above reactions. 'According to this invention, therefore, a process of recovering metals from a mixture containing other sulfids consists 1n treating the mixture with a fused metallic chlorid and electrolyzing the melt at the low temperatures referred to so as to produce the metals and chlorids of sulfur.

The above process is very economical of electric energy and of apparatus.

When zinc is the 'metal under recovery it is desirable to first remove any iron present from the fused chlorids to prevent contamination of the deposlted metal and this may .be carried out by known methods of purification. The preferred method of eliminatto fractionally elecpure molten zinc is afterward substituted from the iron lead alloy and pure zinc there- When however lead is the and sulfid bath it is not necessary to first remove the iron as the latter is always maintained in the ferrous state by the reducingaction of the sulfids present and so does not interfere with the precipitation of lead as it The accompanying drawing is a diagram illustrating one method of carrying this invention into effect as applied for example to a zinc sulfid residue.

The ore from a bin A is fed both to an electrolytic vat B and to a converter C. The ore enters the electrolytic vat at the inlet B through which is also supplied the fused.

zinc chlorid. Chlorid of sulfur is evolved and passes out through the outlet B and the metallic zinc is removed from the outlet B at the bottom of the electrolytic vat. The zinc sulfid residue passes from the ore bin A through the inlet C to the converter, the chlorid of sulfur from the electrolytic vat is introduced through the twyer or other inlet C to the converter. The sulfur chlorid reacts with the zinc sulfid in the converter, the chlorin combining with the zinc to form zinc chlorid and the sulfur being given oif. The reaction takes place according to the following equation:-

ZnS+CCI =ZnCI +S and the resulting zinc chlorid is removed by the outlet C from the converter and returned to the electrolytic vat.

The form of the apparatus can be varied to suit the conditions under which it is used. What I claim as my invention and desire to secure by Letters Patent is 1. A process of recovering metals from a mixture containing their sulfids which comprises treating the mixture with a fused metallic chlorid and electrolyzing the melt at low temperature so as to and chlorids of sulfur.

2. A process of recovering metals from a mixture containing their sulfids which comprises treating the mixture with a fused metallic chlorid and electrolyzing the melt at low temperature to produce the metals and chlorids of sulfur, condensing the chlorids of sulfur and reacting them with metal sulfids to produce sulfur and metal chlorids, findh adding the latter to the electrolytic 3. A process of recovering zinc from a mixture containing zinc sulfid which comprises treating the mixture With fused zinc chlorid and electrolyzing the melt at low produce the metals temperature to produce zinc and chlorid of sulfur.

4. A process of recovering zinc from a mixture containing zinc sulfid which comprises treating the mixture with fused zinc chlorid and electrolyzing the melt-at low temperature to produce zinc and chlorid of sulfur, and reacting the chlorid of sulfur with a mixture containing the zinc sulfid to form zinc chlorid and sulfur, the zinc chlorid being added to the electrolytic bath.

5. A process ofrecovering zinc from a mixture containing zinc sulfid which comprises treating the, mixture with fused zinc chlorid, electrolyzing the melt over a bath of molten lead so as to remove the iron as an alloy, subsequently electrolyzing the melt at low temperature to produce zinc and chlorid of sulfur, and reacting the chlorid of sulfur with a mixture containing the zinc sulfid to form zinc chlorid and sulfur, the zinc chlorid being added to the electrolytic bath.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

EDGAR ARTHUR ASHCROFT.

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