Study on leaching SiO₂ and kinetics of laterite nickel ore in hydrometallurgy

In this paper, laterite nickel ore was combined with NaOH to extract SiO₂ by medium temperature roasting. Firstly, in the single factor experiment, the calcination temperature was 400 °C, the calcination time was 2 h, and the alkali ore ratio was 1.2:1, which was the best calcination conditions. At the same time, the dissolution rate of SiO₂ could reach 98.87%. Then, in order to explore the influence order of different experimental factors on the dissolution rate of SiO₂, the orthogonal experiment was used to determine that the calcination time had the greatest influence on the dissolution rate of SiO₂, followed by the calcination temperature, and finally the alkali ore ratio. Finally, combining kinetic and thermodynamic analysis, the rate equation of the reaction was determined: 1-(1-α)1/3 = 4.9761 × 104 × exp[-5730/(RT)]t, and the reaction process was controlled by the interfacial reaction. Thermodynamic analysis showed that the reaction could proceed spontaneously under certain conditions.