초록 ▼

The present invention is a method to remove arsenic from arsenic-containing materials, such as an ore or concentrate, by roasting the arsenic-containing material to convert arsenic sulfides into arsenic oxides. The arsenic oxides are contained in the roasted arsenic-containing material. The roasted

The present invention is a method to remove arsenic from arsenic-containing materials, such as an ore or concentrate, by roasting the arsenic-containing material to convert arsenic sulfides into arsenic oxides. The arsenic oxides are contained in the roasted arsenic-containing material. The roasted arsenic-containing material is contacted with a lixiviant to solubilize the arsenic in the oxide in a pregnant leach solution. Ferric arsenate, an environmentally stable compound, is formed in the lixiviant. The ferric arsenate can be removed to provide a treated solution complying with environmental regulations. The method provides a simple and effective technique for removing arsenic from arsenic-containing materials.

대표청구항 ▼

[ What is claimed is:] [1.] A method for stabilizing arsenic from an arsenic-containing material, the arsenic being in the trivalent state in the form of a sulfide, comprising:(a) roasting an arsenic sulfide-containing material in the presence of oxygen to form a roasted arsenic-containing material

[ What is claimed is:] [1.] A method for stabilizing arsenic from an arsenic-containing material, the arsenic being in the trivalent state in the form of a sulfide, comprising:(a) roasting an arsenic sulfide-containing material in the presence of oxygen to form a roasted arsenic-containing material wherein (i) the partial pressure of the oxygen is controlled during the roasting step to convert a substantial portion of said arsenic sulfide into arsenic oxide and sulfur dioxide, with the arsenic in the arsenic oxide being in the pentavalent state, while retaining at least about 95% of said arsenic oxide in said roasted arsenic-containing material and (ii) in the instance where the arsenic-sulfide containing material contains iron, the partial pressure of sulfur dioxide is controlled to convert a substantial portion of said iron into an iron-containing salt;(b) contacting said roasted arsenic-containing material with a lixiviant to solubilize said arsenic in said oxide and said iron salt, if any, from said roasted arsenic-containing material to form a pregnant leach solution; and(c) forming ferric arsenate in said pregnant leach solution containing dissolved arsenic.