Patent ID: 6274104
Filing Date: 2001-08-14
Classification: C22B,Y02P

Abstract:
A method for recovering non-ferrous metal from an iron-containing material wherein said non-ferrous metals are chemically converted to non-ferrous metal sulphate compounds through a melt sulphation reaction and the non-ferrous metal sulphate compounds are then isolated, said melt sulphation reaction being optimally achieved by providing iron (III) sulphate in a stoichiometrically balanced proportion to the oxidic and ferritic content and quantity of the material processed in the melt sulphation reaction, the method comprising the steps of:a. reacting the iron-containing material with an alkali metal sulphate, sulphuric acid and water to form a mixture;b. pelletizing the mixture to form a pelletized product containing a non-ferrous metal, iron (III) sulphate and an alkali metal sulphate;c. performing the melt sulphation reaction under oxidizing conditions within a temperature range of 400.degree. C. up to 800.degree. C. on the pelletized product, wherein melt sulphation reaction conditions are such to substantially prevent iron (III) sulphate from thermally decomposing to hematite;d. subsequent to the melt sulphation reaction, leaching the pelletized product with water to form a solution containing dissolved metals of nickel, cobalt, copper, zinc and manganese;e. removing nickel, cobalt, copper, zinc and manganese from the solution by subjecting the solution to hydroxide or sulphide precipitation or ion exchange or liquid-liquid extraction;f. precipitating magnesium as magnesium hydroxide from the solution and removing magnesium hydroxide from the solution; andg. concentrating an alkali metal sulphate selected from the group consisting of sodium sulphate and potassium sulphate in the solution by evaporation to provide an alkali metal sulphate mixture to be recycled, and the water evaporated during the evaporation condensed and recycled.