PROCESS FOR PURIFYING ALUMINIUM-TRIOXIDE

摘要

The iron content of the aluminate liquor process stream as part of the Bayer process of preparing alumina from bauxite is reduced by contacting said stream with a tertiary hydroxyl-containing polyamine. The polyamine is preferentially added between the digestion step and the filtration step to the settler overflow. Generally the polyamine is produced from a monoalkylamine or monoalkanol amine and an epihalohydrin and optionally an alkylene diamine or ammonia.