Effect of Slag Composition on the Solubility of Rhodium in Molten Silicate Slags
Rhodium (Rh) is a key material in catalysts and electronics industries. The rarity of Rh resources makes recycling of Rh a significant issue. Aiming to optimize Rh recovery in an oxidizing atmosphere by controlling slag composition, the dissolution behavior of Rh and the effect of slag composition on Rh solubility was investigated. Rh solubility in slags was measured by equilibrating Na2O-SiO2 and CaO-SiO2 liquid slags with the pure solid Rh at 1473-1873 K in air and the pure O2 atmosphere. For both slag systems, Rh solubility increased with basic oxide content, suggesting that Rh behaves as an acidic substance in slags. The influence of oxygen partial pressure (pO2) on Rh solubility was found to be more significant than that of temperature. From the correlation of Rh solubility and sulfide capacity, it was proposed that Rh dissolves into slag as the rhodate ion, RhO2-. The dependence of Rh solubility in the CaO-SiO2 slag at 1873 K on slag composition was similar to those of Pt and Ru. In addition, the effects of Al2O3 and CuxO, addition to the Na2O-SiO2 slag (X Na2O/X SiO2=0.97)on Rh solubility at 1473 K in air were examined. Al2O3 was found to behave as an acidic oxide and decreased Rh solubility in the slag. In the presence of CuxO, the dissolution of Cu from the slag into the solid Rh was observed. By using the normalized Rh solubility, it was suggested that CuxO addition caused Rh to increasingly dissolve into the slag.
Platinum Group Metals Rhodium Molten Slag Thermodynamics Recycling
Chompunoot WIRASERANEE Takeshi YOSHIKAWA Toru H. OKABE Kazuki MORITA
Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan
国际会议
Ninth International Conference on Molten Slags,Fluxes and Salts(第九届国际熔渣、溶剂与熔盐学术会议 MOLTEN12)
北京
英文
1-10
2012-05-27（万方平台首次上网日期，不代表论文的发表时间）