PROCESS FOR PRODUCING ALUMINUM HYDROXIDE OR ALUMINA BY THE BAYER PROCESS

摘要

The present invention discloses a process for producing aluminum hydroxide or alumina by the Bayer process. The process is characterized in that a refined liquor containing sodium aluminate is used as an original liquor for catalytic decomposition, into which a composite catalyst YHC is added in a proportion of 1-300 % based on the volume of the original liquor in order to conduct the catalytic decomposition. The composite catalyst YHC is formed by mixing a composite catalyst YHA and a composite catalyst YHB. The initial temperature ranges from 30 to 80 ºC, the terminal temperature ranges from 20 to 70 ºC, and the decomposition time ranges from 1.5 to 80 hours. Said composite catalyst YHA is one of surfactants, alcohols and esters, or a mixture of two or more of the preceding substances. Said composite catalyst YHB is one of sugars and inorganics, or a mixture of two of the preceding substances.