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Preliminary study of hydrometallurgical refining of MG-silicon with attrition grinding

1992; Elsevier BV; Volume: 26; Issue: 4 Linguagem: Inglês

10.1016/0927-0248(92)90046-r

1879-3398

Shuang–Shii Lian, Roland Kammel, M.J. Kheiri,

Semiconductor materials and interfaces

We report on our studies to remove impurities such as Fe, Ca, Al, etc., from metallurgical grade silicon MG-Si using a combination of attrition grinding and leaching. The study was divided into two parts. First, impure MG-Si was leached under different conditions in a closed leaching vessel. Second, fine MG-Si was ground with an attritor using different types of grinding balls, grinding media and grinding time. The slurries were then leached again in a leaching vessel. Sulfuric acid reduced the carbon content to some extent and attrition grinding by glass balls plus HCl, combined with leaching by HCl, drastically lowered impurities such as Fe, Al and Ca to around 10 ppm in one hour. This is a much shorter leaching time than has been attained previously. We also found that a particle size of about 1 μm provides the optimum effects on hydrometallurgical refining of MG-Si. Hydrometallurgical refining of MG-Si combined with attrition grinding saves leaching time and allows the use of normal acids such as HCl rather than the use of the caustic and more dangerous HF acid.