Effect of oxidizing agents on the hydrometallurgical purification of metallurgical grade silicon

Low-cost solar grade silicon powder through iterative gettering of thermally treated porous silicon

“…It has reported that HF can react with the oxide film and react with impurities further to enhance the purification effect. In addition, HF can react with inter-granular phases containing impurities in MG-Si, such as Fe-Si-Ti and Si-Fe, which cannot react with other acids as HCl and HNO3 [13][14][15]. Therefore and after thermal annealing, we used a diluted HF acid to remove the PS layer with the trapped impurities.…”

“…Therefore and in order to overcome this problem, many researchers have reported that purity improving of MG-Si can be achieved by (i) thermal decomposition of trichlorosilane at 1100 • C on a heated silicon rod placed inside a deposition chamber (chemical relation 1) [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. This process, which was developed in the late fifties, is commonly referred to as the Siemens process with reference to the company that carried out its early development, (ii) decomposition of monosilane on a heated silicon rod inside a closed deposition chamber (chemical relation 2).…”

Up-grading of locally produced metallurgical grade silicon (MG-Si)

“…Due to the use of different materials, the results of different studies are quite different [9][10][11][12]. Recently, Sahu and Asselin [13] investigated the effects of using two different oxidizing agents, such as ferric chloride and ammonium persulfate, on the purification of MG-Si by leaching with hydrochloric acid. The addition of an oxidizing agent improved the extraction of impurities from the MG-Si.…”

Leaching behavior of impurities in Ca-alloyed metallurgical grade silicon

“…As inexpensive and promising methods, metallurgical purification technologies, such as acid leaching (Ma et al, 2009;Sahu and Asselin, 2012), slag treatment (Cai et al, 2011;Fang et al, 2014), alloying refining (Fang et al, 2013;Morito et al, 2013), directional solidification Martorano et al, 2011), plasma refining (Alemany et al, 2002;Nakamura et al, 2004) and vacuum melting (Safarian and Tangstad, 2012;Zheng et al, 2011), have been receiving more and more attention.…”