Patent ID: 8366801

Claim:
An atmospheric leach process in the recovery of nickel and cobalt from lateritic ores, said process including the steps of: a. providing limonitic and saprolitic ore fractions of a laterite ore; b. separately slurrying the limonitic and saprolitic ore fractions to produce a limonitic ore slurry and a saprolitic ore slurry; c. separating limonitic minerals from the saprolitic ore slurry to produce a saprolitic feed slurry; d. milling or wet grinding the saprolitic feed slurry; e. leaching the limonitic ore slurry with concentrated sulfuric acid in a primary leach step; f. introducing the saprolitic feed slurry from step (d) in a secondary leach step by combining the saprolitic feed slurry from step (d) with the leached limonite slurry following substantial completion of the primary leach step, releasing sulfuric acid to assist in leaching the saprolite feed slurry, wherein the saprolitic feed slurry is substantially free of all limonitic minerals before it is introduced to the leach process.