Na2WO4溶液结晶过程中除砷、硅等杂质
来源期刊：中南大学学报(自然科学版)2001年第3期
论文作者：李运姣 孙昭明 李洪桂 孙培梅 苏鹏抟 刘茂盛
文章页码：251 - 254
关键词：钨酸钠;结晶;除杂
Key words：sodium tungstate; crystallization; removing impurities
摘 要：以机械活化碱分解黑白钨混合中矿及常压碱煮钨渣所得高杂粗钨酸钠溶液(m(As)/m(WO3)=(0.32~2.94)×10-3,m(Si)/m(WO3)=(1.26~5.84)×10-3)为原料进行钨酸钠结晶过程除砷、硅等杂质的研究,分析了结晶率及氧化铝的添加量对除杂效果的影响.试验结果表明:除杂效果与结晶率有关,当结晶率为80%~90%时,除砷率和除硅率均可达90%以上,对m(As)/m(WO3)和m(Si)/m(WO3)分别为3.21×10-4和2.41×10-3的料液而言,除杂后的精液中m(As)/m(WO3)和m(Si)/m(WO3)可分别降至3.50×10-5和3.56×10-4以下.添加Al2O3可明显改善结晶过程中的除杂效果,且Al2O3经化学改性处理后,活性增强,除杂效果更好;在相同条件下,与不加铝盐相比,添加活性Al2O3可使精液中的杂质含量明显降低,除砷率由88.48%增加到94.65%,除硅率由89.77%提高至97.74%.
Abstract: The removal of arsenic and silicon from impure Na2WO4 solution was investigated by crystallization using the iquors (m(As)/m(WO3)=0.32×10-3~2.94×10-3 m(Si)/m(WO3 =1.26×10-3~5.84×10-3) from middle-grade mixed wolframite and scheelite concentrate decomposed with NaOH by mechanical activation and tungstenresidue leached by traditional digestion. The influences of the crystallization ratio and the addition of Al2O3on removing mpurities of As and Si were investigated. It was concluded that the results of removing impurities are related with the crystallization ratio of sodiumtung state and higher than 90% of removal ratio of arsenic and silicon can be obtained under the conditions of 80%~90% of Na2WO4 crystallizing ratio. High quality Na2WO4 solution can be reached and the values less than 3.50×10-5 form(As)/m(WO3) and 3.56×10-4 form(Si)/m(WO3) in the pure Na2WO4 solution can be obtained for the impure Na2WO4solution containing 3.21×10-4ofm(As)/m(WO3) and 2.41×10-3of m(Si)/m(WO3). It was also found that the addition of aluminumoxide can improve the process and better results can be obtained when Al2O3was activated by chemical method. Under the same conditions the removal ratio of arsenic and silicon can be increased from 88.48% to 94.65% and from 89.77 % to 97.74 respectively compared with no Al2O3addition.
