IMPROVED PROCESS FOR PRODUCTION OF PURE AMORPHOUS MESOPOROUS SILICA FROM QUARTZ

摘要

A process for production of amorphous silica from quartz includes the following steps: heating (calcinations step) of quartz with MgCl2, CaCl2 or other metal chlorides, commonly referred to as MeCl2, at a temperature of 800 - 1300 °C wherein the weight ratio of MeCl2 to quartz is greater than 2 and the presence of water vapour in excess of the stoichiometric amount needed; leaching at temperatures preferable between 50 and 130 °C of the produced calcium silicate with HCl to form a solution of MeCl2 with insoluble silica; separation of insoluble silica from the solution; recycling of MeCl2 to the heating step and the HCl solution to the leaching step; ageing the silica in an ageing reactor.