(1. 中南大學(xué) 冶金科學(xué)與工程學(xué)院，長(zhǎng)沙 410083；2. 稀有金屬冶金與材料制備湖南省重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083)
摘 要: 繪制25 ℃時(shí)W-H2O系、Mo-H2O系以及W-Mo-H 2O系中存在的物種隨pH值、鎢、鉬濃度變化的熱力學(xué)平衡圖，并總結(jié)其變化規(guī)律。熱力學(xué)分析表明：W-Mo-H2O系中的鎢、鉬在酸化過(guò)程中一般經(jīng)歷從單體離子到雜多酸根離子再到同多酸根離子的轉(zhuǎn)變過(guò)程。在pH值為6.5~7.5的范圍內(nèi)，鎢轉(zhuǎn)變成聚合離子的程度均高于鉬，表明單鎢酸根離子的聚合能力強(qiáng)于單鉬酸根離子的；而在pH值為3.0~6.5的弱酸性區(qū)間內(nèi)，溶液中形成濃度較高的鎢鉬雜多酸根離子，這對(duì)于鎢鉬分離極其不利。
關(guān)鍵字: W-Mo-H 2O系；鎢鉬分離；熱力學(xué)分析；鎢鉬雜多酸；聚合離子
（1. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China;2. Hunan Key Laboratory for Metallurgy and Material Processing of Rare Metals, Central South University, Changsha 410083, China）
Abstract:The thermodynamic equilibrium diagrams for the distribution of species at different pH values, tungsten and molybdenum concentrations in W-H2O, Mo-H2O and W-Mo-H2O systems at 25 ℃ were drawn, and the variational regularities of species were also analyzed. The thermodynamic analysis shows that the tungsten and molybdenum are transformed from monomeric anions to heteropolyanions, then to isopolyanions during the acidification process in W-Mo-H2O system. The polymeric degree of tungsten is significantly higher than that of molybdenum in the pH range from 6.5 to 7.5, which indicates that the polymeric ability of monotunstates is stronger. At pH values of 3.0-6.5, the heteropolymolybdotungstate ions with higher concentration are formed, which is extremely unfavorable to the separation of tungsten and molybdenum.
Key words: W-Mo-H2O system; separation of tungsten and molybdenum; thermodynamic analysis; heteropolymolybdotungstate; polymeric ions
