Abstract: The invention provides method to recover, by means of froth flotation, a desired metal value from a feedstock containing it. In a comminution step, the feedstock is comminuted using comminuting media of an iron and chrome steel alloy comprising from 12% to 30% chrome. In a conditioning step, the feedstock material is contacted with thiourea and/or oxalic acid as primary flotation reagents. The conditioning step comprises the comminution step, in which a quantity of the primary flotation reagent/s being added and preconditioned comminuted feedstock material being obtained. The conditioning step also comprises an optional conditioning finishing step, in which a mixture of the preconditioned comminuted feedstock material and a liquid is subjected to stirring and with conditioned comminuted feedstock material being obtained from the finishing step. In a recovery step, at least some of the desired metal value is recovered by froth flotation from the preconditioned or conditioned feedstock.

Abstract: The method for nickel concentration processing, which is low cost, simple and convenient, as well as having low environmental load, which is capable of enhancing nickel content of a saprolite ore with low nickel content, which was not conventionally used effectively as a raw material of ferronickel smelting due to having low nickel content, to a level to be utilized economically as a raw material of ferronickel smelting.

Abstract: The method for nickel concentration processing, which is low cost, simple and convenient, as well as having low environmental load, which is capable of enhancing nickel content of a saprolite ore with low nickel content, which was not conventionally used effectively as a raw material of ferronickel smelting due to having low nickel content, to a level to be utilized economically as a raw material of ferronickel smelting. The method is characterized by including the steps of the following (1) to (4). (1) a saprolite ore is subjected to crushing processing to adjust the ore particle size to a size passing a sieve with an mesh opening of 50 mm. (2) a crushed ore is subjected to dry-type grinding processing of the surface layer part by attrition. (3) a ground ore is subjected to dry-type classification processing at a classification point to be selected from 0.5 to 2.0 mm, and then an ore portion having a particle size of equal to or smaller than the classification point is recovered as a nickel concentrate.

Abstract: A copper concentrate obtained by flotation of a high grade copper ore containing chalcopyrite as a main mineral constituent is leached at a temperature of 100° C. or higher, and under a pressure greater than atmospheric pressure yielding a copper leachate containing ferric ions of at least 5 g/L and sulfuric acid, and this copper leachate is used in heap leaching or vat leaching of a low grade copper ore, whereby a method of recovering copper economically from a material containing copper is provided.

Abstract: A copper concentrate obtained by flotation of a high grade copper ore containing chalcopyrite as a main mineral constituent is leached at a temperature of 100° C. or higher, and under a pressure greater than atmospheric pressure yielding a copper leachate containing ferric ions of at least 5 g/L and sulfuric acid, and this copper leachate is used in heap leaching or vat leaching of a low grade copper ore, whereby a method of recovering copper economically from a material containing copper is provided.

Abstract: A method is provided for decomposing free cyanide ion and metallic cyano complex ions in a liquid, comprising the steps of bringing the liquid into contact with ozone gas in a counterflow relation in the condition that the pH of the liquid is at least 10 with the mass flow rate of the ozone in the ozone gas up to 20 mg per minute per liter of liquid, and then bringing the liquid into contact in a counterflow relation with ozone gas having an ozone concentration of at least 150 g/m3 in the condition that the pH of the liquid is 7.0 to 9.5.