Production of Silicone Tetrachloride from Rice Husk by Chlorination and Performance of Mercury Adsorption from Aqueous Solution of the Chlorinated Residue

The production of silicone tetrachloride (SiCl4) from rice husk char by chlorination was investigated, and the effect of the char preparation temperature on SiCl4 volatilization and the coexisting element species in the char was examined. The behavior of chlorine (Cl) and the change in pore properties during char chlorination were analyzed, and the reaction mechanism was discussed. The performance of Hg ion removal of the chlorination residue was also investigated. At 1000 °C chlorination, the optimum rice husk pyrolysis temperature for attaining high ash-release extent was 800 °C. Ash volatilization during char chlorination with heat treatment mainly occurred at >300 °C and reached a release extent of ∼75% by 1000 °C. Si and P volatilization started at >300 °C and reached 70–75% by 1000 °C. In contrast, Na and K the volatilization occurred at >700 °C, with a 50% volatilization extent by 1000 °C. Mg and Ca had a volatilization rate of