At present, there are three methods for preparing silica sol in China: ion exchange method, acid neutralisation method, electrodialysis method, silica powder dissolution method and gelatinisation method. Ion exchange method is mostly used for the domestic method, but this method is more process procedures, energy consumption; electrolysis electrodialysis method in the operation process will occur in the adsorption of silica deposition on the anode, the voltage and power consumption is relatively high, and silica sol is easy to polymerisation; acid neutralisation method is poor stability and colloidal method requires high conditions.
The preparation of silica sol with metallic silicon powder has a simple process, lower cost and better product quality, which is more suitable for small and medium-sized enterprises to produce.
Experiments show that the more the amount of metal silicon powder, the higher the content of SiO2 in the silica sol, the better the quality of silica sol, but adding too much metal silicon powder will bring certain difficulties to the vacuum filtration and recycling of metal silicon powder reuse, also taking into account the economic reasons, the amount of metal silicon powder should be 160 parts as appropriate.
