Numerical simulation and experimental verification of axial-directional crystallization purification process for high-purity gallium
(1. Key Laboratory for Ecological Metallurgy of Multimetallic Mineral of Ministry of Education, Northeastern University, Shenyang 110819, China;
2. School of Metallurgy, Northeastern University, Shenyang 110819, China;
3. Key Laboratory of New Processing Technology for Nonferrous Metals & Materials of Ministry of Education, Guilin University of Technology, Guilin 541004, China)
2. School of Metallurgy, Northeastern University, Shenyang 110819, China;
3. Key Laboratory of New Processing Technology for Nonferrous Metals & Materials of Ministry of Education, Guilin University of Technology, Guilin 541004, China)
Abstract: A transient numerical model was applied to simulating the axial-directional crystallization purification (ADCP) process of gallium (Ga) raw material at different coolant temperatures (Tc), and the evolutions of melt/crystal (m/c) interface shape, temperature distribution and thermal stresses were simulated and analyzed. The results showed that the m/c interface shape, temperature distribution, and thermal stress in the Ga material were determined by the Tc in the crystallizer during the ADCP process. The temperature gradient and thermal stress in the grown Ga crystal increased with decreasing Tc. At Tc=15 °C, the m/c interface shape was flat, and the temperature gradient was ideal. Therefore, the Ga materials with lower thermal stresses and suitable m/c interface shape, and an ideal efficiency of impurity removal were obtained. The purity of Ga reached 6N standard by using ADCP process repeated 6 times at Tc of 15 °C. The results of the simulation showed good agreement with the experimental results.
Key words: high purity Ga; axial-directional crystallization purification; finite element method