采用热重?质谱联用技术，结合XRD分析，考察了红土镍矿与Na2SO4共热解的特性，对热解气态产物进行了分析. 结果表明，红土镍矿与硫酸钠共热解可分为5个阶段：游离水析出阶段(37?152℃)、针铁矿分解脱羟基阶段(238?278℃)、利蛇纹石和高岭土脱羟基阶段(554?602℃)、白云石分解阶段(892?914℃)和Na2SO4分解阶段(1241?1286℃). H2O, CO2和SO2是红土镍矿与硫酸钠共热解过程析出的主要气体. 根据Coasts模型，红土镍矿与硫酸钠共热解为一级反应，热解机制是Na2SO4中的Na+取代富镍硅酸盐中的Ni2+，被置换出的Ni2+与游离氧结合形成NiO，有利于下一步还原焙烧?磁选富集镍.
The thermal decomposition of Na2SO4 and nickel laterite was investigated by thermogravimetry coupled with mass spectrometer (TG?MS) and X-ray diffraction (XRD). The evolution of the thermal decomposition gas composition was detected by mass spectrometry. The results indicated that the thermal decomposition process of Na2SO4/nickel laterite can be divided into five stages: the evaporated of the free water (37~152℃), the dehydroxylation of the goethite (238~278℃), the dehydroxylation of the lizardite and kaolinite (554~602℃), the dolomite decomposition (892~914℃) and the decomposition of Na2SO4 (1241~1286℃). The main volatile products of the pyrolysis are H2O, CO2 and SO2. According to the Coasts model, the decomposition of nickel laterite with Na2SO4 can be described by one first-order reaction. The mechanism of Na2SO4/nickel laterite thermal decomposition may be Na+ replaced Ni2+, which is an isomorphic host in the lattice of (Ni,Mg)2SiO4. Ni2+ was released and reacted with O2? to form NiO, which facilitated nickel enrichment through the process of reduction roast-low intensity magnetic separation.
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