Upgrading of copper concentrates from flotation

Abstract

Abstract Copper sulphide concentrate is recovered from an ore containing sulphides of copper and of iron by floating the ore to obtain a rougher concentrate containing a major proportion of the recoverable copper sulphide, separating the concentrate into sands and slimes, treating the sands in an alkaline state with a soluble cyanide and subjecting the treated sands to a flotation operation whereby the copper sulphide content of the sands is in large part recovered in the resulting concentrate and flotation of the iron sulphide content is in large part inhibited. Essentially, the ore is ground to about minus 65 mesh and the ground ore is the subject to a rougher flotation operation. The rougher float tails are passed through a scavenger float, the tails from this scavenger float being discarded and the concentrate usually, but not necessarily, being reground and returned to the rougher float. The rougher float concentrate is separated in a hydrocyclone into sands and slimes. The sands are treated with a soluble cyanide in the presence of lime or with crude calcium cyanide and, preferably after regrinding, are floated to produce a finished concentrate and tails. The tails either directly or after a scavenger float may be discarded, or directly or after the scavenger float recycled to the sand-slime separation step or fed back to the rougher float. The separated slimes may be added directly to the sand flotation step, or they may be sent to a smelter with the finished sand concentrate, or they may be floated separately the concentrate being sent to the smelter and the tails being discarded directly or after a scavenger float. The slimes scavenger float concentrate is recycled, preferably to the rougher float. Examples of modifications of the process are given and proportions of cyanide and line are specified. The preferred soluble cyanide is crude calcium cyanide, but sodium cyanide, hydrocyanic acid, and other alkali or alkaline earth cyanides or organic cyanides, e.g. lactonitrile, may be used.

Inventors

• 👤 Cadwell Edward Peter

Bibliographic Details