China Nonferrous Metallurgy

A large amount of waste containing In-Bi will be produced during processing the new high-performance transparent conductive oxide film (IBO). In addition, with the wide application of IBO, IBO waste target will also increase. In the process of vacuum distillation for separation and purification, the saturated vapor pressure of In and Bi is similar, so it is difficult to obtain satisfactory process parameters. The vapor-liquid equilibrium (VLE) phase diagram can be used to guide the practice of vacuum distillation. In this paper, vacuum distillation experiments were carried out with the configured In-Bi alloy as raw material to obtain the VLE value of In-Bi alloy, and MIVM was used to predict the activity and gas-liquid equilibrium data of In-Bi alloy components. The following conclusions were obtained. under the conditions of system pressure of 5~10Pa and distillation temperature of 1183K, when the In content in the residue is 80.80%, the Bi content in the volatiles reaches 97.17%, which indicating that the In-Bi alloy can be separated by vacuum distillation. The molecular interaction volume model (MIVM) was used to calculate the activity of components of In-Bi alloy. The average standard deviations of the calculated values and the experimental data were ± 0.0139 and ±0.007, respectively, and the average relative deviations were ±11.216% and ±11.4521%, respectively. The results show that the MIVM is reliable for predicting the activity of In-Bi alloy. The vapor-liquid equilibrium (VLE) data of In-Bi alloy was predicted based on the MIVM. A comparison shows that the predicted value is consistent with the experimental data determined in this study, which indicates that the MIVM is reliable for predicting the VLE value of indium-based alloys and can be used to guide the separation of indium-based alloy by vacuum distillation. The reliability of the MIVM model was verified and the process parameters for vacuum distillation separation of indium-based alloys are also optimized based on the model prediction and vacuum distillation experiments. This study will provide guidance for vacuum separation and purification of indium-based alloys or processing of complex materials containing indium.