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研究了从钠盐焙烧稀土精矿中高压酸浸稀土,分析了高压酸浸动力学。稀土精矿经高温焙烧,其中的氟碳铈矿和独居石全部分解为氧化稀土(RExOy)。焙砂水洗后进行高压酸浸,考察了浸出温度、浸出时间、盐酸浓度、液固体积质量比对稀土浸出率的影响。结果表明:在75℃下浸出50 min,控制盐酸浓度7 mol/L、液固体积质量比10 mL/1 g、压强在3 MPa条件下,稀土浸出率达89.4%;在40~50℃条件下,反应表观活化能Ea=29.55 kJ/mol,机制函数为ln(1-x)/3+(1-x)-1/3
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