The reaction behaviors of silicate species in （NH4）2WO4-（NH4）2CO3-NH3-H2O system are crucial to developing a greenmanufacture technique for ammonium paratungstate. In order to efficiently remove silicon from the s...The reaction behaviors of silicate species in （NH4）2WO4-（NH4）2CO3-NH3-H2O system are crucial to developing a greenmanufacture technique for ammonium paratungstate. In order to efficiently remove silicon from the system, the reaction behaviors ofsilicate species were systematically investigated by thermodynamic analysis. The thermodynamic analysis shows that silicate in thetungstate clinker partly decomposes in the leaching process, with 150-160 mg/L silicon thermodynamically at 25 ℃. The dissolvedsilicon can be removed by magnesium salts via forming insoluble MgSiO3. The low carbonate and high ammonia concentrations inthe system are beneficial to the removal of silicon, with silicon concentration reaching 8-10 mg/L thermodynamically, whereasMgSiO3 precipitation is hardly formed when the concentration of total carbonate is more than 1.5 mol/L. The reaction behaviors ofcalcium and magnesium were also studied in the system. The results in the verification experiments consist with the theoreticalcalculation.展开更多
基金Project(51274243)supported by the National Natural Science Foundation of ChinaProject(2015CX001)supported by the Innovation-driven Plan of Central South University,China
文摘The reaction behaviors of silicate species in （NH4）2WO4-（NH4）2CO3-NH3-H2O system are crucial to developing a greenmanufacture technique for ammonium paratungstate. In order to efficiently remove silicon from the system, the reaction behaviors ofsilicate species were systematically investigated by thermodynamic analysis. The thermodynamic analysis shows that silicate in thetungstate clinker partly decomposes in the leaching process, with 150-160 mg/L silicon thermodynamically at 25 ℃. The dissolvedsilicon can be removed by magnesium salts via forming insoluble MgSiO3. The low carbonate and high ammonia concentrations inthe system are beneficial to the removal of silicon, with silicon concentration reaching 8-10 mg/L thermodynamically, whereasMgSiO3 precipitation is hardly formed when the concentration of total carbonate is more than 1.5 mol/L. The reaction behaviors ofcalcium and magnesium were also studied in the system. The results in the verification experiments consist with the theoreticalcalculation.
