Process of leaching sulfide containing materials with hot,strong sulfuric acid

Abstract

Abstract MATERIAL SUCH AS ORES, CONCENTRATES, AND THE LIKE CONTAINING SULFIDES OF COPPER, IRON, ZINC, LEAD MOLYBDENUM, ETC., WITH OR WITHOUT PRECIOUS METALS, ARE TREATED WITH STRONG SULFURIC ACID, THE CONCENTRATION BEING MAINTAINED BETWEEN 80% AND 100%. THE AMOUNT OF SULFURIC ACID IS LESS THAN 3.8 MOLES PER MOLAR EQUIVALENT IN THE SULFIDES WHICH REACT AND PREFERABLY IS 3 MOLES OR LESS. THE TEMPERATURE IS MAINTAINED BETWEEN 160* AND 250*C. AND THE PARTICLE SIZE OF THE SULFIDE AND GANGUE MATERIAL IS PREFERABLY NOT IN EXCESS OF 8 MESH. THE REACTION IS EFFECTED IN PASTE OR SEMI-SOLID FORM IN APPARATUS SUCH AS A ROTARY KILN, AND PREFERABLY THE CONCENTRATION OF SULFURIC ACID IS MAINTAINED BY EVAPORATION OF WATER FORMED. UNDER THESE CONDITIONS AT LEAST 10% OF THE SULFUR CONTENT OF THE REACTING SULFIDES, AND PREFERABLY AT LEAST 50%, IS RECOVERED IN THE FORM OF ELEMENTAL SULFUR. TO IMPROVE DISTRIBUTION OF HEAT AND REACTANT, LARGER PARTICLES, SUCH AS INERT PEBBLES OF AT LEAST 1/4", ARE USED, WHICH LARGER PARTICLES BECOME COATED WITH THE REACTANTS AND ARE EFFECTIVELY TUMBLED IN THE KILN WHILE REACTION OCCURS IN THE COATING. THE REACTION MAY BE CARRIED OUT IN STAGES, WITH THE EARLIER STAGES MAXIMIZING SULFUR PRODUCTION AND LATER STAGES UNDER MORE DRASTIC CONDITIONS AFTER INTERSTAGE REMOVAL OF ELEMETAL SULFUR.

Inventors

• 👤 W Fuchs

Bibliographic Details