Method and means for using microwave energy to oxidize sulfidic copper ore into a prescribed oxide-sulfate product

Abstract

The present invention is directed to the microwave treatment of a class of selected metal ores and concentrates, particularly those known as chalcopyrite, in a fluidized bed reactor. The end product is commonly a mixture of copper oxide and copper sulfate, both of which are liquid soluble and directly recoverable by known techniques. The ratio of the oxide-sulfate mixture end product may be controlled by suitable control of microwave parameters.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]The present application claims the benefits of U.S. Provisional Application Ser. No. 60 / 826,350, filed Sep. 20, 2006 entitled “Method and Means for Using Microwave Energy to Oxidize Sulfidic Copper Ore into a Prescribed Oxide-Sulfate Product”, which is incorporated herein by this reference.FIELD OF THE INVENTION[0002]The invention relates generally to the recovery of selected transition metals from sulfidic materials and particularly to the recovery of base metals, particularly copper, from sulfidic materials.BACKGROUND OF THE INVENTION[0003]Chalcopyrite is a commonly occurring sulfidic copper ore which must be oxidized to liberate the copper and make it amenable to conventional recovery techniques, which include smelting and solvent extraction (SX / EW). Due to the modest value of the finished copper metal, there is always a need for lower-cost methods of production. Coupled with this is the environmental concern over historical smelter ope...

AI Technical Summary

Benefits of technology

"The present invention is about a process for oxidizing selected metal sulfides to render them recoverable using microwave energy. This process can be used to recover copper, nickel, cobalt, and manganese from sulfidic materials. The process involves microwave energy being passed through a bed of sulfidic material while a fluidizing gas is passed through the material. This results in the oxidation of selected metal sulfides, the formation of oxidized metal sulfates or non-sulfur containing metal oxides, and the removal of the oxidized material from the reactor. The process can be carried out using microwave energy alone or in combination with other heating methods such as radiant thermal energy. The use of microwaves can provide energy savings and the process can be used with low concentration ores and concentrates. The ratio of sulfur-free copper oxides to copper sulfates can be controlled, which can be important in downstream metal recovery processes. The process is efficient and economical, especially for low concentration ores and concentrates."

Problems solved by technology

A large portion of the cost of producing copper product is the cost associated with the production of the high-value concentrate.

Of this, grinding is the most energy consumptive and costly, however this is an unavoidable step in conventional concentration which relies on increasingly finer grinding to liberate (and separate) the sulfide particles (containing the copper) within the ore.

Reaction (3) is actually an intermediate reaction which, upon further oxidation, produces CuO.Fe2O3 which is an insoluble spinel product and is therefore undesirable.

As well, Kruesi does not disclose an applicator or device in which the microwave process can be practiced such that the process variables (temperature, feed rate, gas composition, gas / solids intermixing) can be controlled as in an industrial process.

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