Method for recovering a copper sulfide concentrate from an ore containing an iron sulfide
In a method for recovering a copper sulfide concentrate by froth flotation from an ore containing an iron sulfide, wet grinding of the ore with grinding media made of high chromium cast iron alloy having a chromium content of from 10 to 35% by weight is combined with an addition of hydrogen peroxide to the conditioned mineral pulp before or during flotation in order to improve concentrate grade and recovery of copper sulfides.
1. A method for recovering a copper sulfide concentrate from an ore containing an iron sulfide, comprising the steps of:
a) wet grinding the ore with grinding media to form a mineral pulp,
b) conditioning the mineral pulp with a collector compound to form a conditioned mineral pulp, and
c) froth flotation of the conditioned mineral pulp to form a froth and a flotation tailing, separating the froth from the flotation tailing to recover the copper sulfide concentrate,
wherein the grinding media comprise grinding media made of high chromium cast iron alloy with a chromium content of from 10 to 35% by weight and hydrogen peroxide is added to the conditioned mineral pulp between steps b) and c) or during step c).
2. The method of claim 1 , wherein the grinding media are high chromium cast iron alloy balls.
3. The method of claim 1 , wherein the high chromium cast iron alloy is a high chromium white iron alloy comprising a carbide phase.
4. The method of claim 1 , wherein the high chromium cast iron alloy is a martensitic solid solution free from pearlite and comprising less than 5% by weight austenite.
5. The method of claim 1 , wherein the hydrogen peroxide is added less than 15 minutes before a gas is introduced for froth flotation.
6. The method of claim 1 , wherein froth flotation is carried out continuously and hydrogen peroxide is added continuously during froth flotation.
7. The method of claim 1 , wherein hydrogen peroxide is added as an aqueous solution comprising 0.5 to 5% by weight hydrogen peroxide.
8. The method of claim 1 , wherein the collector compound is an alkali metal alkyl xanthate.
9. The method of claim 1 , wherein hydrogen peroxide is added in an amount of from 0.5 to 10 times a target amount, the target amount being determined in a series of preliminary experiments in which the amount of added hydrogen peroxide is varied, the concentration of dissolved oxygen is determined in the mineral pulp after addition of hydrogen peroxide, the concentration of dissolved oxygen is plotted against the amount of added hydrogen peroxide to give a curve having an inflection point, and the target amount of hydrogen peroxide is determined as the amount of hydrogen peroxide at the inflection point.
10. The method of claim 1 , wherein the concentration of dissolved oxygen is determined in the mineral pulp after addition of hydrogen peroxide and the amount of hydrogen peroxide added is adjusted to maintain a minimum concentration of dissolved oxygen.
11. The method of claim 2 , wherein hydrogen peroxide is added as an aqueous solution comprising 0.5 to 5% by weight hydrogen peroxide.
12. The method of claim 3 , wherein hydrogen peroxide is added as an aqueous solution comprising 0.5 to 5% by weight hydrogen peroxide.
13. The method of claim 4 , wherein hydrogen peroxide is added as an aqueous solution comprising 0.5 to 5% by weight hydrogen peroxide.
14. The method of claim 2 , wherein the hydrogen peroxide is added less than 15 minutes before a gas is introduced for froth flotation.
15. The method of claim 3 , wherein the hydrogen peroxide is added less than 15 minutes before a gas is introduced for froth flotation.
16. The method of claim 4 , wherein the hydrogen peroxide is added less than 15 minutes before a gas is introduced for froth flotation.
17. The method of claim 11 , wherein the hydrogen peroxide is added less than 15 minutes before a gas is introduced for froth flotation.
18. The method of claim 12 , wherein the hydrogen peroxide is added less than 15 minutes before a gas is introduced for froth flotation.
19. The method of claim 13 , wherein the hydrogen peroxide is added less than 15 minutes before a gas is introduced for froth flotation.
20. The method of claim 9 , wherein the high chromium cast iron alloy is a martensitic solid solution free from pearlite and comprising less than 5% by weight austenite.