Atmospheric acid leach process for laterites

摘要

An atmospheric leach process in the recovery of nickel and cobalt from lateriticores, said process including the steps of : a) providing limonitic and saproliticore fractions of a laterite ore; b) separately slurrying the limonitic and saproliticore fractions to produce a limonitic ore slurry and a saprolitic ore slurry; c)separating any limonitic type minerals from the saprolitic ore slurry to producea saprolitic feed slurry; d) milling or wet grinding the saprolitic feed slurry;e) leaching the limonitic ore slurry with concentrated sulfuric acid in a primaryleach step; f) introducing the saprolitic feed slurry to the leach process ina secondary leach step by combining the saprolitic feed slurry with the leachedlimonite slurry following substantial completion of the primary leach step,releasing sulfuric acid to assist in leaching the saprolite feed slurry, whereinthe saprolitic feed slurry is substantially free of all limonitic type mineralsbefore it is introduced to the leach process.