Chlorination leaching with sulfur extraction for recovery of zinc values

• US 4,346,062 A
• Filed: 02/13/1981
• Issued: 08/24/1982
• Est. Priority Date: 01/14/1981
• Status: Expired due to Fees

• Current Assignee: Occidental Research Corporation (Occidental Petroleum Corporation)
• Original Assignee: Occidental Research Corporation (Occidental Petroleum Corporation)
• Inventors: Au, Robert W.
• Primary Examiner(s): Hearn, Brian E.
• Application Number:
  US06/234,128
• Time in Patent Office: 557 Days
• Field of Search: 423/101, 423/103, 423/110, 423/109, 423/568, 75/104, 75/120
• US Class Current: 205/605
• CPC Class Codes: C22B 19/02 Preliminary treatment of ores; Preliminary refining of zinc oxide
• CPC Class Codes: C22B 19/22 with leaching with acids
• CPC Class Codes: Y02P 10/20 Recycling

Abstract

A process is disclosed for recovering zinc from a material containing zinc sulfide. The zinc sulfide-containing material is chlorinated in an aqueous medium to form zinc chloride and elemental sulfur. A water-immiscible solvent (preferably inert) for the sulfur is added to the aqueous chlorinating solution during the chlorination process. The aqueous solution which contains zinc values is separated from the water-immiscible solvent containing sulfur. The zinc values can be recovered from the aqueous layer.

Claims

1. A process for recovering zinc values from zinc sulfide-containing material, comprising the steps of:

(a) partially chlorinating zinc sulfide-containing material in an aqueous medium including recycle solution from step (i) and an aqueous chlorination leaching solution containing elemental chlorine and ferric chloride, in the presence of a water immiscible solvent for sulfur at a temperature below the melting point of sulfur and at about atmospheric pressure, to form an aqueous layer containing zinc chloride, iron, chlorine and partially chlorinated solid residue and a water-immiscible solvent layer containing sulfur;

(b) separating the aqueous layer and water-immiscible solvent layer from the solid residue,

(c) separating the aqueous layer containing zinc chloride, iron and chlorine from the immiscible solvent layer containing sulfur;

(d) treating the separated aqueous layer with elemental chlorine and an alkali to precipitate ferric hydroxide;

(e) separating precipitated ferric hydroxide from the aqueous layer;

(f) recovering zinc values from the aqueous layer;

(g) dissolving the precipitated ferric hydroxide in an acidic medium to form a secondary leaching solution;

(h) leaching additional zinc values from the solid residue with the secondary leaching solution in the presence of chlorine to form a recycle solution containing zinc chloride and iron chloride; and

(i) returning the recycle solution to step (a).

2. A process as recited in claim 1 wherein the water-immiscible solvent for sulfur is 1,1,2,2-tetrachloroethane.

3. A process as recited in claim 1 wherein the temperature is from about 80°

C. to about 110°

C.

4. A process as recited in claim 1 wherein the amount of iron in the partially chlorinating step, provided by ferric chloride and recycle solution, is less than about ten percent by weight of the slurry formed by the zinc sulfide-containing material, recycle solution, aqueous chlorination leaching solution and water-immiscible solvent for sulfur.

5. A process for recovering zinc values from zinc sulfide-containing material, comprising the steps of:

(a) partially chlorinating zinc sulfide-containing material in an aqueous medium including recycle solution from step (i) and an aqueous chlorination leaching solution containing elemental chlorine and ferric chloride in the presence of 1,1,2,2-tetrachloroethane, at about atmospheric pressure, at a temperature in the range of 80°

to about 110°

C. and below the melting point of sulfur, to form an aqueous layer containing zinc chloride, iron, chlorine and partially chlorinated solid residue and a water-immiscible solvent layer containing sulfur; and

wherein the amount of iron provided by said ferric chloride and said recycle solution is less than about ten percent by weight of the slurry formed by the zinc sulfide-containing material, recycle solution, aqueous chlorination leaching solution and water-immiscible solvent for sulfur;

(b) separating the aqueous layer and water-immiscible solvent layer from the solid residue;

(c) separating the aqueous layer containing zinc chloride, iron and chlorine from the immiscible solvent layer containing sulfur;

(d) treating the separated aqueous layer with elemental chlorine and an alkali to precipitate ferric hydroxide;

(e) separating precipitated ferric hydroxide from the aqueous layer;

(f) recovering zinc values from the aqueous layer;

(g) dissolving the precipitated ferric hydroxide in an acidic medium to form a secondary leaching solution;

(h) leaching additional zinc values from the solid residue with the secondary leaching solution in the presence of chlorine to form a recycle solution containing zinc chloride and iron chloride; and

(i) returning the recycle solution to step (a).