| Abstrakt: |
In this study, the laterite nickel ore was treated by basic hydrothermal method, and the product was dissolved directly in the form of sodium silicate. Pure SiO2 was obtained by carbonizing sodium silicate solution. The effects of various conditions on silicon extraction rate were studied by single factor experiment. The optimum conditions of silicon leaching were as follows: NaOH concentration 75%, reaction temperature 220 ℃, reaction time 110 min, liquid-solid mass ratio 4.5:1, stirring intensity 350 r/min. Orthogonal experiments were carried out to optimize the experimental parameters, and the relationship between the main and secondary factors affecting the extraction rate of silicon was determined as follows: leaching temperature > leaching time > liquid-solid mass ratio > NaOH concentration. The reaction kinetics of the mixed system was studied, and the control steps of the hydrothermal reaction process were found, that is, the process of alkali leaching of silicon from laterite nickel ore was consistent with the diffusion control law of solid product layer. Corresponding dynamic equations can be expressed as 1–3(1-α)2/3 + 2(1-α) = 6.16 × exp(-8860/RT)t. Taking SiO2 obtained under the optimal optimization level as raw material, the Li2MnSiO4 cathode material with good properties was creatively prepared by high temperature calcination method. The performance of Li2MnSiO4/C obtained by calcination at 650 ℃ is the best. This study provides guidance for extracting Si elements from natural minerals to prepare valuable materials. [ABSTRACT FROM AUTHOR] |
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