URLAKNING AV ICKE-JAERNHALTIGA METALLER OCH JAERN INNEHAOLLANDE SULFIDHALTIG METALLSTEN

摘要

A method of treating sulphidic mattes containing from 5% to 60% iron; from 15% to 40% sulphur together with soluble non-ferrous metals such as copper, cobalt, nickel and zinc and also optionally insoluble non-ferrous metals which term includes platinum group metals gold and silver by a leaching process to effect substantial separation of the non-ferrous metals from iron as well as from insoluble residue material. The matte is contacted in a finely subdivided form with sulphate in acid medium at a temperature of from 70 DEG C. to 120 DEG C. and an oxygen partial pressure of from 50kPa to 1,000kPa. The quantity of sulphate present is at least the stoichiometric amount required for dissolving the soluble non-ferrous metals present but is limited to ensure that a substantial proportion of iron which dissolves simultaneously with the soluble non-ferrous metals precipitates out as it is replaced by dissolving non-ferrous metals.