Iron, aluminum and, if appropriate, calcium containing silicon for use in the reaction to chlorosilanes or organosilanes and method for its production

摘要

A Si-compsn. contg. Fe,Al, and (optionally) Ca, as an intermetallic phase when added to Si in amounts of 0.1-5% by wt. (esp. 0.1-1%) improves the reaction performance in the conversion of Si to chloro- and organosilanes. In this respect, the degree of conversion, productivity, and selectivity (eg the proportion of Si converted to monochlorotrimethyl-silane) are all enhanced. The intermetallic phases, FeAl3Si2 and Fe4Si6Al4Ca are prepd. by reaction of the appropriate quantities of metals with Si in the molten state, and on cooling the intermetallic phase solidifies out. USE/ADVANTAGE- Improves the economics of the process of making Si derivs. by increasing conversion, selectivity, and productivity, also reduces quantity of by-products. Specifically: A Si compsn was produced contg. 10%Si and 90% FeAl3Si2. This was pulverised to a particle size of less than 0.2mm and mechanically mixed with metallurgical Si at a dose rate of 1:99. The doped Si was then reacted with MeCl at 300 deg C in a reactor under pressure. In a comparative test the same reaction was carried out using pure Si. Results (pure Si in brackets) Productivity g/hr 8.05 (6.10), selectivity % 85.8 (84.1).