PROCESSING OF ULTRA-DISPERSED POWDER ON THE BASIS OF SILICON DIOXIDE OR PRODUCTS MADE FROM THE ULTRA-DISPERSED POWDER ON THE BASIS OF SILICON DIOXIDE

摘要

1. A method of purifying an ultrafine silica-based powder or an article made from an ultrafine silica-based powder, said method comprising treating said ultrafine silicon dioxide-based powder or said article made from an ultrafine silicon dioxide-based powder at least , one of the following compounds: (i) a mixture of CO and Cl in a carrier gas, where the total concentration of CO and Cl in said mixture is more than 10 vol.% and the ratio of CO to Cl is from 0.25 to 5; (ii) CCl in a gas carrier, where the concentration of CCl is more than 1% by volume. 2. A method for purifying an ultrafine silica-based powder or an article made from an ultrafine silica-based powder according to claim 1, wherein the ratio of CO to Cl is from 0.5 to 2.3. A method for purifying an ultrafine silica-based powder or an article made from an ultrafine silica-based powder according to claim 1, wherein the ratio of CO to Cl is from 0.75 to 1.5. A method for purifying an ultrafine powder based on silicon dioxide or a product made from an ultrafine powder based on silicon dioxide according to claims 1 to 3, in which the treatment with a mixture of CO and Cl is carried out at a temperature of 900 to 1200 ° C. A method for purifying an ultrafine powder based on silicon dioxide or an article made from an ultrafine powder based on silicon dioxide according to claim 4, wherein the treatment with a mixture of CO and Cl is carried out at a temperature from 1000 to 1200 ° C. Method for cleaning ultrafine powder based on silicon dioxide or a product made from ultrafine powder