| 摘要 |
<p>A method of extracting and concentrating small quantities of precious metals such as gold, silver and platinum contained in high sulphur content base metal sulphide ore residues comprises mixing the ore residue with extra copper or other suitable base metal, e.g. by pelletising with powdered copper, smelting and casting the mixture to form a two phase block having an upper lighter layer rich in sulphur and a lower denser metal layer rich in the precious metals and then treating the lower layer for the recovery of a concentrate containing the precious metals. If the correct amount of copper or other base metal be added a relatively small lower layer is formed so that the precious metals are not too dispersed and a sharp line of demarcation if formed between the two layers. <IMAGE></p> |
