Study on efficient drying process of industrial silicon powder

The drying procedure is an important consideration for the silicon powder processing. Herein, a comparative investigation of the drying efficiency, drying performance, and energy consumption of silicon powder after separation and purification of monocrystal silicon cutting slurry by using the hot air, far-infrared and microwave drying treatments. The results show that microwave drying of 30 g silicon powder takes only 12 min, which is much shorter than hot air drying of 200 min and far infrared drying of 40 min. The water evaporation energy consumption of microwave drying reached 73.5 g/kW·h, which was 3.3 times than that of far infrared drying and 16.5 times than that of hot air drying. For 1 kg of silicon powder, the power consumption of microwave drying was 8 kW·h, while the far-infrared drying was 26.7 kW·h, and the hot air drying was 133.4 kW·h, respectively. Therefore, effects of microwave power, drying temperature and drying time on the dehydration rate of silicon powder were investigated and optimized by response surface method, demonstrating that the microwave drying dehydration rate of 30 g silicon powder could reach 97.65%, and the power consumption could be reduced to 6.7 kW·h/kg under the conditions of microwave power of 1000 W, drying temperature of 89°C and drying time of 12 min. The present study shows that microwave drying of silicon powder is an energy-saving and efficient process with good industrial application prospects.