Microwave-drying process and mineral phase analysis of low-grade complex laterite ores
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摘要: 研究了在碳化硅輔助吸波作用下,低品位紅土鎳礦在微波場中的干燥過程.采用熱重分析(DTG)、X射線衍射(XRD)和傅里葉變換紅外光譜(FT-IR)分析考察了添加不同質量分數碳化硅對失重率和產物物相的影響.結果表明:碳化硅與紅土礦配比R為2.2:1時,微波干燥處理低鎳、鐵品位紅土礦30min,既可快速脫除礦物絕大部分表面吸附水和部分結晶水;通過控制碳化硅的比例還可以避免過熱現象.微波能夠改變紅土礦的微觀結構,促進礦物的分解.進一步的氫還原實驗表明,微波干燥有利于紅土礦中鎳和鐵氧化物的還原,其還原率高于常規干燥.Abstract: 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.
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Key words:
- laterite /
- phase composition /
- microwaves /
- drying /
- silicon carbide
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