Recovery of non-ferrous metals from zinc residues
(19) AUSTRALIAN PATENT OFFICE(54) (51)6 Title Recovery of non-ferrous metals from zinc residues International Patent Classification(s) C22B 19/04 (2006.01) 20060101ALI20060101 (2006.01) BHAU C22B 5/16 (2006.01) 20060101ALI20060101 (2006.01) BHAU C22B (2006.01) 13/02 (2006 01) 20060101ALI20060101 BHAU C22B 19/34 20060101AFI20060101 (21)(87)(30) (31) BHAU C22B 5/1020060101ALI20060101 20060101AU20060101 BHAU BHAU C22B 5/12PCT/EP2004/006238 Application No: 2004256162 WIPO No: WO05/005674 (22) Application Date: 2004 .06.08 Priority Data Number (32) Date (33) 60/484,648 2003 .07.07 03077120.8 2003.07.04 Country US EP (43) (71) (72) (74) Publication Date : 2005 .01 .20 Applicant(s) Umicore Inventor(s) Van Camp, Maui its; Janssens, Benedict; Aerts, Jonathan Agent/Attorney Davies Collison Cave, Level 15 1 Nicholson Street, MELBOURNE, VIC, 3000 -1- The invention relates to a process for the separation and recovery of non-ferrous metals from zinc-bearing residues, in particular from residues produced by the zinc manufacturing industry. The process allows for the valorisation of metal values in a Zn-, Fe- and Pb-bearing residue, and comprises the steps of: subjecting the residue to a direct reduction step, thereby producing a metallic Fe-bearing phase and Zn- and Pb-bearing first fumes; extracting the Zn- and Pb-bearing first fumes and valorising Zn and Pb; subjecting the metallic Fe-bearing phase to an oxidising smelting step, thereby producing an Fe-bearing slag and second metals-bearing fumes; extracting the second metals-bearing fumes and valorising at least part of their metallic content. The main advantage of this process is that an environmentally acceptable output for Fe is obtained. i. Process for the valorisation of metal values in a Zn-, Feand Pb-bearing residue, comprising the steps of:
- subjecting the residue to a direct reduction step, thereby producing a metallic Fe-bearing phase and Znand Pb-bearing first fumes; - extracting the Znand Pb-bearing first fumes and valorising Zn and Pb; - subjecting the metallic Fe-bearing phase to an oxidising smelting step, thereby producing an Fe-bearing slag and second metals-bearing fumes; - extracting the second metals-bearing fumes. 2. Process according to claim i, whereby in the direct reduction step, a metallic Fe-bearing phase containing at least 50% of the Fe contained in the Zn-, Feand Pb-bearing residue is obtained. 3. Process according to claim 2, whereby in the direct reduction step, a metallic Fe-bearing phase containing at least 90% of the Fe contained in the Zn-, Feand Pb-bearing residue is obtained. 4. Process according to claim I, 2 or 3, wherein during the oxidising step Fe in the metallic Fe-bearing phase is oxidised to mainly FeO in the slag. 5. Process according to claim 4, whereby in the oxidising smelting step at least 50% of the Fe in the metallic Fe-bearing phase is oxidised to FeO. 6. Process according to claim 5, wherein at least 90% of the Fe in the metallic Fe-bearing phase is oxidised to FeO in the oxidising smelting step. 7. Process according to any one of claims 1 to 6, wherein the Zn-, Feand Pb-bearing residue is a neutral leach residue or a weak acid leach residue. 8. Process according to claim 4, 5 or 6, wherein an acidic flux is present in the oxidising smelting step. 9. Process according to claim 8, wherein the acidic flux is present in the oxidising smelting step as a mixture of an acidic and a basic flux. i0. Process according to any one of claims 1 to 9, wherein the Zn-, Feand Pb-bearing residue contains Cu and Ag, and, during the oxidising smelting step, a separate Cu-alloy phase is produced containing a major part of the Cu and Ag. ii. Process according to any one of claims 1 to i0, wherein the Zn-, Feand Pb-bearing residue contains Ge, and, after the direct reduction step, the fraction of the Ge present in the first fumes is separated and forwarded to the oxidising smelting step. 12. Process according to claim ii, wherein the separation of Ge is performed by co-precipitation with Fe hydroxide or by addition of tannic acid. 13. Process according to any one of claims 1 to I0, wherein the Zn-, Feand Pb-bearing residue contains Ge, and, after extracting the second metals-bearing fumes, at least part of their metallic content is valorised. 14. Process according to any one of claims 1 to 13, wherein the first fumes are oxidised in the reactor used for the direct reduction step. 15. Process according to any one of claims 1 to 14, wherein the reactor used for the direct reduction step is a multiple hearth furnace. 16. Process according to any one of claims 1 to 15, wherein the reactor used for the oxidising smelting step is a submerged lance furnace. 17. Process for the valorisation of metal values in a Zn-, Fe- and Pb-bearing residue, substantially as hereinbefore described with reference to the example. 18. Non-ferrous metal values recovered from a Zn-, Feand Pbbearing residue by a process according to any one of the preceding