低品位复杂红土镍矿微波干燥及矿相分析

Microwave-drying process and mineral phase analysis of low-grade complex laterite ores

研究了在碳化硅辅助吸波作用下,低品位红土镍矿在微波场中的干燥过程.采用热重分析(DTG)、X射线衍射(XRD)和傅里叶变换红外光谱(FT-IR)分析考察了添加不同质量分数碳化硅对失重率和产物物相的影响.结果表明:碳化硅与红土矿配比R为2.2:1时,微波干燥处理低镍、铁品位红土矿30min,既可快速脱除矿物绝大部分表面吸附水和部分结晶水;通过控制碳化硅的比例还可以避免过热现象.微波能够改变红土矿的微观结构,促进矿物的分解.进一步的氢还原实验表明,微波干燥有利于红土矿中镍和铁氧化物的还原,其还原率高于常规干燥.

Silicon carbide as a assistant wave-absorbing material was used to study the microwave-drying process of a low-grade laterite ore.The effects of SiC mass fraction on the weight-loss rate and phase composition of the laterite ore were analyzed by thermogravimetric analysis （DTG）,X-ray diffraction analysis （XRD） and Fourier transform infrared spectroscopy （FT-IR）.It is shown that when the SiC-to-ore mass ratio is 2.2：1,most of surface-absorbed water and part of crystal water in the laterite ore can be rapidly removed by microwave drying for 30 min.Overheating phenomena can be avoided by controlling the addition amount of SiC,too.Microwave treatment changes the microstructure and promotes the decomposition of the laterite ore.Hydrogen reduction experiment results indicate that the microwave-drying process benefits to the reduction of nickel and iron oxides in the laterite ore.The reduction rates of iron and nickel in samples through microwave drying are higher than those through conventional drying.