由扎布耶盐湖粗盐制备高纯碳酸锂新工艺研究

根据西藏扎布耶湖的高锂镁比特性，以卤水析出的粗碳酸锂为原料，确定了经济实用的化学分步碱化沉淀，去除杂质元素，最后碳酸化沉淀碳酸锂的提纯工艺。研究了沉淀工艺、不同水体系和沉淀剂对碳酸锂纯度的影响。采用等离子发射光谱、红外光谱、X射线衍射、扫描电镜等对高纯碳酸锂进行表征。结果表明，最佳工艺条件是在纯净水体系中经化学分步碱化沉淀，去除铁、铝、镁、钙等杂质，最后碳酸铵沉锂，可获得纯度为99.90%以上的白色松软的高纯碳酸锂。红外谱图和XRD衍射谱图显示样品为扎布耶型的纯碳酸锂；扫描电镜显示碳酸锂晶体为棒状，长为3~5 μm，直径为0.5 μm以下。

New process for preparation of high purity lithium carbonate from coarse salt in Zabuye Salt Lake

According to the characteristics of high Li-Mg ratio of the Zabuye Lakes，coarse lithium carbonate separated from the brine was used as the raw material and an economical and practical chemical precipitation method was introduced to eliminate the impurity through fractional alkalization，and then the carbonated precipitation had been applied to get high purity lithium carbonate.The influence of different water systems，process of sedimentation，and carbonation precipitant on the purity of lithium carbonate had also been investigated.High purity lithium carbonate was characterized by plasma emission spectrum（ICP），infrared（IR），X-ray diffraction（XRD），and scanning electron microscopy（SEM）.Result indicated that the optimum conditions were as follows: the main impurity of Fe，Al，Mg，and Ca were removed by step-by-step chemical precipitation in the pure water system and then precipitation by ammonium carbonate subsequently.The ICP result showed the lithium carbonate was loose and white and its purity was more than 99.90%.The IR and XRD spectra showed there was zabuyelite type lithium carbonate only，and the lithium carbonate particles were uniform rods with 3~5 μm in length and below 0.5 μm in diameter.