Patent ID: 8470272

Claim:
A magnesium recycling and sulfur recovery method in leaching of lateritic nickel ores, the method comprising the steps of: (I) granulometric separation of coarse and fine material; (II) heap leaching of the coarse material and atmospheric leaching of the fine material; (III) neutralization of the leached material with addition of a first concentration of MgO pulp in two stages to increase the pH value up to approximately 2.5 during a first stage, and then up to approximately 4.5 during a second stage via addition of a second concentration of MgO lower than the first concentration, and to hydrolyze the iron, aluminum and copper; (IV) solid-liquid separation of the neutralized leached material; (V) purification of the separated solid with a diluted solution of H 2 SO 4 in combination with a reducing agent; (VI) manganese removal from the purified separated solid using ozone gas in conjunction with MgO; and (VII) crystallization under pressure to promote recovery of MgSO 4 .