application of a procedure for the extraction of nickel from nickel sulphide minerals

摘要

1404246 Nickel and copper recovery ANACONDA CO 26 March 1973 [23 June 1972] 14421/73 Heading C1A Nickel and optionally copper are recovered from sulphidic minerals by leaching a slurry of the minerals in aqueous solution containing ammonium sulphate and free ammonia in one, or sequentially a series of closed leaching vessels at low pressure (10 p.s.i.g.) at a temperature of 65-80‹ C., whilst recirculating oxygen bearing gas from above the slurry to below the surface thereof, vigorously agitating the slurry with a power input of 0À05 h.p./cu. ft. of slurry and introducing fresh oxygen into the slurry, and withdrawing from the vessels a solution containing the nickel (and copper if present) complexed with the ammonia. Free ammonia may be added to at least the first of the vessels at a rate equal to its consumption, and the concentration of the ammonia may be correlated with the slurry temperature which gradually rises through the series whilst the pH decreases from about 10 to 9À5. The solution may be treated to recover the nickel (and copper) and form ammonium sulphate solution which may be recycled.