化学法制备高纯碲过程中杂质元素脱除的热力学分析
来源期刊：中南大学学报(自然科学版)2006年第2期
论文作者：马玉天 龚竹青 陈文汨 李宏煦 阳征会 杨余芳
文章页码：257 - 262
关键词：热力学分析;硫化沉淀;净化;高纯碲
Key words：thermodynamic analysis; sulfide precipitation; purification; high-purity tellurium
摘 要：通过对Te(Ⅳ)-Pb(Ⅱ)-Cu(Ⅱ)-As(Ⅲ)-H2O和Te(Ⅳ)-MeS-H2O系热力学分析,得到溶液中Te(Ⅳ), Pb(Ⅱ),Cu(Ⅱ)和As(Ⅲ)离子总浓度与溶液pH值、温度以及溶液中S2-浓度的关系。热力学分析结果表明:采用硫化物沉淀法可以深度净化Na2TeO3溶液,去除其中大部分重金属离子及砷离子,确定理论上去除Na2TeO3溶液中Pb(Ⅱ),Cu(Ⅱ)和As(Ⅲ)离子的最佳pH值为11左右。采用硫化物沉淀法对Na2TeO3溶液中Pb(Ⅱ), Cu(Ⅱ)和As(Ⅲ)离子的净化实验验证了热力学分析的正确性,通过实验使粗TeO2中的Pb, Cu和As杂质的质量分数由0.273 0%,0.165 9%和0.280 0%分别降低到3.24×10-4%, 1.00×10-4%和1.30×10-3%,但S2-浓度过量对As的去除不利。实验确定硫化沉淀法去除杂质离子的最佳条件是: pH=11,温度为373 K,反应时间为50 min。
Abstract: By thermodynamic analysis on system of Te(Ⅳ)-Pb(Ⅱ)-Cu(Ⅱ)-As(Ⅲ)-H2O and Te(Ⅳ)-MeS-H2O, the relationship between total concentration of Te(Ⅳ), Pb(Ⅱ), Cu(Ⅱ),As(Ⅲ) and pH value, reaction temperature, concentration of S2-was established. Thermodynamic analysis results show that most heavy metallic ions and As(Ⅲ) in Na2TeO3 solution can be removed thoroughly by sulfide precipitation method. The theoretic optimum pH value for sulfide precipitation to remove the impurities from Na2TeO3 solution is about 11. The experimental results confirm the thermodynamic analysis results. Pb, Cu and As in raw TeO2are removed from 0.273 0%, 0.165 9% and 0.280 0% to 3.24×10-4%, 1.00×10-4% and 1.30×10-3%, respectively. And an excess of S2-is not in favor of As removal from Na2TeO3 solution. According to experimental results the optimum process parameters are as follows: pH=11, reaction temperature of 373 K, reaction time of 50 min.
基金信息：国家自然科学基金资助项目
