Sintering Process for Limonitic Nickel Laterite

Land-based nickel resources include nickel sulfide and nickel laterite. With the consumption of high grade nickel sulfide, use of nickel laterite has received more and more attention. The mineralogy and sintering behavior of limonitic nickel laterite with high iron and low nickel and silica was studied to offer technical support for producing ferronickel through sintering-blast furnace route. The mineralogy results showed that the main phases in this kind of nickel laterite are goethite (FeO(OH)), gibbsite (Al(OH)₃) and NiFe₂O₄. The TGA (Thermogravimetric Analysis) and DSC (Differential Scanning Calorimetry) revealed hydroxide minerals in addition to absorbed water. After the sintering experiments the chemical composition, phases present (XRD analysis) and physical properties of the sinter were studied. The content of FeO in the sinter increased with increasing basicity up to 1.3, and then decreased with further increase in basicity. The yield of sinter increased (from 73% to 80%) with increase in the basicity from 1.1 to 1.7, and then the yield decreased with the further increase in basicity. Mg(Ni)(Fe,Al)₂O₄ is the main phase in the sinter while MgCaSiO₄ and Fe₂SiO₄ is the main binder phase when the basicity is 1.1~1.5, and MgCaSiO₄, Fe₂SiO₄ and SFCA is the main binder phase when the basicity is 1.7~2.1.