开发碳酸钠碱熔焙烧预处理红土镍矿的新工艺,对红土镍矿碱熔脱除铬和铝动力学以及矿石粒度和碱矿质量比、焙烧温度等影响铬和铝浸出率的因素进行系统研究。结果表明：在矿石粒度为44-74μm、碱矿质量比为0.6：1和焙烧温度为1000℃的条件下,铬和铝的浸出率分别达到99%和82%以上。在600-800℃温度范围内,除铬反应受产物层扩散控制,其表观活化能为3.9 k J/mol;在900-1100℃温度范围内,除铬反应受表面化学反应控制,其表观活化能为54.3 kJ/mol。此外,在600-1100℃温度范围内,除铝反应受Avrami内扩散控制,其表观活化能为16.4 kJ/mol。在后续对碱熔渣进行加压酸浸过程中,镍和钴的浸出率分别达到96.8%和95.6%。
A chemical precipitation–thermal decomposition method was developed to synthesize Co_3O_4 nanoparticles using cobalt liquor obtained from the atmospheric pressure acid leaching process of nickel laterite ores. The effects of the precursor reaction temperature, the concentration of Co^(2+), and the calcination temperature on the specific surface area, morphology, and the electrochemical behavior of the obtained Co_3O_4 particles were investigated. The precursor basic cobaltous carbonate and cobaltosic oxide products were characterized and analyzed by Fourier transform infrared spectroscopy, thermogravimetric differential thermal analysis, X-ray diffraction, field-emission scanning electron microscopy, specific surface area analysis, and electrochemical analysis. The results indicate that the specific surface area of the Co_3O_4 particles with a diameter of 30 nm, which were obtained under the optimum conditions of a precursor reaction temperature of 30℃, 0.25 mol/L Co^(2+), and a calcination temperature of 350℃, was 48.89 m^2/g. Electrodes fabricated using Co_3O_4 nanoparticles exhibited good electrochemical properties, with a specific capacitance of 216.3 F/g at a scan rate of 100 mV/s.
Long MengZhan-cheng GuoJing-kui QuTao QiQiang GuoGui-hua HouPeng-yu DongXin-guo Xi
