Study of the process of obtaining water glass from silica gel for use in metallurgy

This study explores the possibility of producing a sodium silicate solution (liquid glass) using industrial raw materials for subsequent use in metallurgical practice. The object of the study was industrial waste from the production of aluminium fluoride, i.e., silica gel, which comprises a fine powder of silicon dioxide with a moisture content of over 55 wt %. Silica gel was purified using a low-concentration solution of sulfuric acid. The synthesis of liquid glass was carried out using the HEL Auto-Mate Reactor System. The silicon content in the solution was determined by X-ray fluorescence method using the Shimadzu EDX-7000P analyzer. To determine the alkali content in the resulting product, a titrimetric analysis method was used. The preliminary purification process allowed silica gel with an amorphous silica content of over 98 wt % to be obtained. The optimal parameters of the liquid glass production were defined: temperature – 100°C, process time – 4.5 hours, mixing speed – 300 rpm, and the concentration of the initial alkaline solution – from 10 to 17.5 wt %. The resulting liquid glass solution had a mass content of silicon dioxide from 16.65 to 23.77 wt % and a silicate module from 2.72 to 3.16, which meets the requirements of marketable products for various industries. Based on the experimental results, optimal parameters for the production of liquid glass using industrial raw materials, i.e., silica gel, are proposed. Liquid glass with the defined characteristics can be further used as a binder in metallurgical processes.