Process for the preparation of amorphous silica.

摘要

The invention provides a process for the production of a high grade amorphous silica having a purity of at least 90% active silica of the formula SiO2.nH2O, comprising the steps of: a. comminuting and wet classification of porcellanite rock to form granules having an average diameter of 200 microns to 8mm; b. combining the resulting granules with NAOH at a temperature of up to 100 DEG C to form a product containing sodium silicates; c . separating a liquid containing the sodium silicates from solid waste; d . adding CO2 to the liquid product to form SiO2.nH2O and Na2CO3; e . washing the resulting product to effect a separation of the precipitated SiO2.nH2O from the soluble Na2CO3; and f. recovering SiO2.nH2O of a purity of at least 90%. f