| 摘要 |
The invention provides a process for the production of amorphous silica from a silica-based material having a silica content of at least 90% comprising: a) heating said silica-based material with CaCl2, at a temperature in the range of about 900~C to about 1,200~C and in the presence of water vapor in excess of the stoichiometric amount needed for the reaction: x CaCl2 + y SiO2 + x H 2O .fwdarw. (CaO)x .bullet. (SiO2)y + 2x HCl wherein x is equal to or greater than y to obtain a conversion of said silica-based material to calcium silicates in excess of 99.9%; b) Leaching said calcium silicates with HCl to form a solution of CaCl2 with insoluble silica; c) separating said insoluble silica from solution; and d) recycling the CaCl2 solution from step "c" to step "a".
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