HIGH PURITY SILICA SOL AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a production method capable of using a water glass as a raw material and obtaining a high purity silica sol having a lower content of Cu and Ni as metallic impurities as compared with the conventional one and to provide a high purity silica sol having a lower content of Cu and Ni as metallic impurities.SOLUTION: There is provided a method for producing a high purity silica sol which comprises the following steps [1] and [2]: [1]: A step of applying an ion exchange method to an alkali silicate aqueous solution containing an alkali silicate having an average molecular weight of 30000 or less to obtain a purified silicate solution by removing at least a part of cation components contained in the purified alkali silicate aqueous solution. [2] A step of obtaining high quality silica sols in which each of Cu and Ni concentration is 100 ppb or less on a dry silica basis by using the a purified silicate solution.