| 摘要 |
<p>Gold values are recovered from an ion-exchange resin containing gold, copper, and nickel by contacting the resin in a first step with an alkali metal cyanide solution, e.g. NaCN, to elute copper and nickel, and iron and zinc if present, in a second step with a mineral acid, e.g. H2SO4, to remove further copper and nickel, and in a third step with an alkaline solution of a thiocyanate, e.g. N H4CNS or NaCNS. The resin is obtained by passing a cyanide solution, obtained from the dressing of ore, through a predominantly weakly basic anion exchange resin, e.g. a polystyrene type, in the salt form. After the third step, the resin may be regenerated by mineral acid solution. The eluants in the first, second and fourth steps may be used in a number of fractions. In a succession of cycles of operation, the first fractions of the first and second steps of the first cycle are added to the original cyanide solution for gold leaching, while the second fraction becomes the first in the second cycle, the third becomes the second, and so on. The last fraction of the first step of the second cycle is a fresh cyanide solution, while the last fraction of the second step in the second cycle was the first fraction of the resin regeneration in the first cycle. The last fraction of the resin regeneration is a fresh acid solution. The gold is recovered from the eluate of the third step, e.g. by electrolysis, and the stripped eluate is used in the second cycle. Specification 901,572 is referred to.</p> |
