FOERFARANDE FOER EXTRAHERING AV NICKELHALTIG METALLSTEN INNEHAOLLANDE JAERN I LUFTKRETSTRYCK

摘要

1486039 Leaching nickeliferous matte AMAX Inc 27 Oct 1975 [26 Dec 1974] 44161/75 Heading C1A Nickeliferous sulphide matte containing by weight 20-75% Ni, 5-50% Cu, 4-20% S, and 0À5-20% Fe, the sum of the Ni, Cu and S contents being at least 80% of the matte composition, and the sulphur content being less than required to stoichiometrically combine with the metal values in the matte and not more than the amount required to combine with the Ni and Ni 3 S 2 is prepared as a granulated product by quenching a melt thereof from a temperature at least 10‹ C. above its liquidussolidus temperature and below its boiling point, and is then comminuted, subjected to a first atmospheric leaching with a spent copper electrolyte containing sufficient H 2 SO 4 to give a pH of up to 2 while aerating with air until the pH of the solution reaches 3À5 to 4À5, further subjected to a second atmospheric leaching in said spent electrolyte by adding to the matte, or replacing said air with, oxygen MnO 4 -1, or S 2 O 8 2- until the pH rises to over 5 to form a nickel-containing solution and a nickel-copper residue, which is separated from the solution and subjected to a sulphuric acid leaching step at elevated temperature and pressure to recover metal values therefrom. The matte may be subjected to a sulphuric acid pre-leach at pH 1-3 to remove iron therefrom following the comminution step.