1results about How to "Increase ionic strength" patented technology

This application relates to a low-alpha-ray silica and its preparation method. The method involves adding a high-purity sodium sulfate solution to water glass, followed by the sequential addition of dilute sulfuric acid solutions of varying concentrations for aging. The resulting precipitate is then calcined to obtain low-alpha-ray silica with Th ≤ 5 ppb and U ≤ 5 ppb. The sodium sulfate solution optimizes the precipitation process in two ways: first, it increases the ionic strength of the solution, compresses the colloidal double layer, and disrupts the metastable state of the system, thus promoting the aggregation and crystallization of the target precipitate; second, sulfate ions preferentially complex or inhibit the precipitation tendency of impurity cations based on the common ion effect; furthermore, the dilute sulfuric acid solution promotes the reaction and rapid precipitation of silicate ions with hydrogen ions, causing the Th and U ions encapsulated in the precipitate to precipitate out, thereby reducing the impurity content in the solution. This low-alpha-ray silica, due to its extremely low Th and U content and good thermal conductivity, can be widely used in high-performance and special-purpose chip packaging fields.