Acid Leaching Process of Laterite Nickel Ore with High Iron Content and Low Grade
The change of iron grade in the leaching residue and the leaching kinetics under normal pressure and pressure were examined.The pressure leaching of nickel and cobalt from a high iron and low grade laterite nickel ore in Indonesia with sulfuric acid was studied.The results show that under the conditions of acid/ore ratio of 260 kg/t,leaching temperature of 250 ℃(corresponding to water vapor pressure of 4.0 MPa),liquid volume/solid mass ratio of 3/1,stirring speed of 300 r/min,particle size of 100 mesh and reaction time of 1 h,the leaching rates of nickel,cobalt and iron are 98.1％,98.3％and 4.7％,respectively,and the iron grade can reach 51.3％.The leaching processes of nickel and cobalt under pressure and atmospheric pressure are in line with the shrinkage kernel model of interfacial chemical reaction control,and the activation energies of the reactions are 116 kJ/mol and 91 kJ/mol under pressure,respectively,and the activation energies of the reaction under atmospheric pressure are 41 kJ/mol and 53 kJ/mol,respectively.The leaching is mainly goethite under normal pressure,and chromite,magnetite and other mineral phases under high pressure.
laterite nickel orehigh iron contentlow gradenickelcobaltacid leachingdynamics
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