Method for removing alkali metal compound from crude high-molecular weight substance

摘要

A method for purifying a crude high-molecular weight substance containing an alkali metal compound by extracting the alkali metal compound with water is disclosed, which comprises stirring a mixture comprising said crude high-molecular weight substance and water in a high-speed stirring tank to extract the alkali metal compound into an aqueous phase and separating the high-molecular weight substance phase and the aqueous phase from each other by continuous centrifugation. An alkali metal compound as an impurity can be efficiently removed with small-sized equipment in a short time.