Method of recycling nickel, cobalt, iron and silicon from low-grade laterite nickel ore through combined leaching process

• Main Authors: HUI YU, WANG JIHUA, LI FENXIA, SHA BIN, CHEN XUEAN, ZHU HUI, WANG SHAOHUA, YANG ZHIQIANG, LIU YUQIANG, TANG JIN
• Format: Patent
• Language: English
• Published: 12.08.2015
• Subjects: CHEMISTRY; CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION ORPROCESSING OF GOODS; COMPOUNDS THEREOF; FERROUS OR NON-FERROUS ALLOYS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; INORGANIC CHEMISTRY; METALLURGY; NON-METALLIC ELEMENTS; PRETREATMENT OF RAW MATERIALS; PRODUCTION AND REFINING OF METALS; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE; TREATMENT OF ALLOYS OR NON-FERROUS METALS

The invention discloses a method of recycling nickel, cobalt, iron and silicon from low-grade laterite nickel ore through a combined leaching process. The method includes the following steps: (a) performing washing classification to the low-grade laterite nickel ore to obtain high-silicon and -magenisum ore and low-silicon and -magenisum and high-iron ore; (b) adding heated high-silicon and -magenisum ore slurry and concentrated sulfuric acid into a double-screw material-pushing reactor; (c) dissolving reaction materials in water and performing solid-liquid separation and filter residue washing to obtain a normal-pressure leached residue, a normal-pressure leached liquid and a washing liquid; (d) performing pressurized leaching to the low-silicon and -magenisum and high-iron ore slurry and the normal-pressure leached liquid in a pressurized pot, wherein the Fe<3+> in the normal-pressure leached liquid is hydrolyzed to release acid for leaching the low-silicon and -magenisum and high-iron ore slurry again; (e) decreasing the temperature and performing the solid-liquid separation to obtain a pressurized leached residue and a pressurized leached liquid; (f) removing non-nickel and -cobalt impurities from the pressurized leached liquid, and recycling the nickel and/or the cobalt through a known method; (g) washing the pressurized leached residue through a sodium carbonate solution and washing the pressurized leached residue to obtain iron fine powder; and (h) screening the normal-pressure leached residue to obtain silicon dioxide and fine sand. The method is high in leaching rate of nickel and cobalt, is less in acid consumption and can effectively recycle iron and partial silicon.