Study On The Fabrication Of Scattered Metals Ga By High Purification Technique

The second generation of gallium arsenide and the third generation of gallium nitride semiconductor material have been used widely since the silicon semiconductor material,the demand of high-purity gallium increases rapidly.A lot of research has been done on the preparation of high-purity gallium to meet the requirements of GaAs,GaP,GaN and other semiconductor materials at home and abroad.In this paper,the partial crystallization method is adopted to prepare high-purity gallium,with the advantage of simple production process,low energy consumption,simple operation and short production cycle.According to the properties of gallium and the principle of crystallization,Selection of crystallization purification experiment of thick gallium(99.99%)was conducted.We designed the purification flow of crystallization.The effects of cooling water flow,temperature on cooling rate,solidification rate and crystal growth were examined in detail and the process parameters were determined.We also determined the optimal experimental parameters.We successfully prepared 6N(99.9999%)and 7N(99.99999%)high-gallium products in accordance with the relevant national standard through the multiple purification.The following results were obtained.(1)When the cooling water flow Q<60L/h,the crystallization rate increases constantly with increasing the cooling water flow,While when the cooling water flow rate Q>60L/h,the crystallization rate no longer changes with the flow,the functional relation of crystallization with flow is V=9.94-2.86-Q/e76.82,the cooling water flow control in 40 to 60L/h makes uniform crystal growth.(2)The crystallization rate decreases constantly with the cooling water temperature increasing,the cooling water temperature control in 18 to 20 ? makes uniform crystal growth and crystal grain size is consistent,the functional relation of crystallization rate with temperature is V=-68.56 +111.54-T/e55.87.(3)When the cooling water temperature is 20?,the functional relation of cooling rate with flow is VC=2.36-0.27/1+eQ-48.02/1.25.When the cooling water flow is 60L/h,the functional relation of cooling rate with temperature is VC= 55.48 T-1.05.(4)When the cooling water flow and seed number,solidification rate is constant,the purification effect with the cooling water temperature of 20 ? is better than 18 ?;(5)When the cooling water flow and cooling temperature,solidification rate is constant,the purification effect with grafting six crystal seed is better than four.(6)The results above show that the best technological parameters are cooling water flow of 60 L/h,Cooling water temperature of 20?,grafting six symmetrical distribution crystal seed and solidification rate of 90%.Crystallization purification experiment under the condition of optimum process parameters,Testing results show that after 7 times recrystallization the product purity can reach the national standard of 6N high-purity gallium,and the product yield is 46.55%;after 8 times recrystallization the product purity can reach the national standard of 7N high-purity gallium,and the product yield is 42.08%.