# US 4,394,164 A · Process for removal of harmful impurities from metallurgical sulphide melts

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- Number: US 4,394,164 A
- Document ID: US4394164A
- Status: Granted
- Kind: A
- Application number: 06/305,508
- Filed: 1981-09-25
- Granted: 1983-07-19
- Earliest claimed: 1980-09-26
- Assignees: Outokumpu Oy
- Inventors: Juho K. Makinen; Kaarina M. E. Kaenniemi
- Web page: https://patentgrep.com/patent/US4394164A

## CPC

- C22B 15/006: {working up of molten copper, e.g. refining}
- C22B 5/02: Dry methods {smelting of sulfides or formation of mattes}
- C22B 9/05: Refining by treating with gases, e.g. gas flushing {also refining by means of a material generating gas in situ}
- C22B 23/025: {with formation of a matte or by matte refining or converting into nickel or cobalt, e.g. by the Oxford process (leaching of mattes C22B23/04)}
- C22B 23/06: Refining
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS

## Abstract

A process for the removal of harmful impurities, particularly arsenic, antimony, bismuth and lead, from metallurgical sulphide melts, in which the sulphide melt is sulphurated before conversion, during the slag-blowing stage or after it before the blister-blowing stage, and the melt is refined with nitrogen or other inert gas during sulphuration and possibly after it, so that the amount of sulphur supplied to the sulphide melt is at least 10% in excess of the stoichiometric sulphur amount as calculated from the sulphur requirement of the principal components of the melt.

## Claims

### Claim 1

A process for the removal from metallurgical sulphide melts of harmful impurities selected from the group consisting essentially of arsenic, antimony, bismuth and lead, comprising sulphurating the sulphide melt in an inert gas atmosphere by feeding into the melt a sulphur containing agent in an amount such that the sulphur supplied to the sulphide melt is at least 10% in excess of the stoichiometric sulphur amount as calculated from the sulphur requirement of the principal components of the melt.

### Claim 2 (depends on 1)

A process according to claim 1, in which the sulphur containing agent is elemental sulphur vapour.

### Claim 3 (depends on 1)

A process according to claim 1, in which the sulphur containing agent is a compound selected from the group consisting essentially of pyrites, pyrrhotites, covellite and hydrogen sulphide.

### Claim 4 (depends on 1)

A process according to claim 1, in which the temperature of the melt is held in the range 1100.degree.-1300.degree. C. during sulphuration.

### Claim 5 (depends on 1)

A process according to claim 1, in which, in sulphurating copper converter matte, the amount of sulphur is raised 10-15% above the stoichiometric sulphur amount as calculated from the sulphur requirement of CU.sub.2 S, Ni.sub.3 S.sub.2 and FeS.

### Claim 6 (depends on 1)

A process according to claim 1, in which, in sulphurating matte containing nickel as the principal component, the amount of sulphur is raised 20-25% above the stoichiometric sulphur amount as calculated from the sulphur requirement of CU.sub.2 S, Ni.sub.3 S.sub.2 and FeS.

### Claim 7 (depends on 1)

A process according to claim 1, in which additional heat is supplied to the melt while carrying out an inert gas rinse using hot gas after sulphuration.

### Claim 8 (depends on 1)

A process according to claim 1, in which the sulphide melt sulphurated contains as the principal metal one or more of copper, nickel, cobalt and iron.

### Claim 9 (depends on 1)

A process according to claim 1 in which the melt is converted before or after sulphuration.

### Claim 10 (depends on 9)

A process according to claim 9, wherein slag is blown in a slag-blowing stage before or during the sulphuration.