Method for recycling alkali and aluminum during treatment of Bayer red mud by using calcification-carbonization process

摘要

Disclosed is a method for recycling alkali and aluminum during the treatment of Bayer red mud by using a calcification-carbonization process. The method comprises the steps of: mixing Bayer red mud with calcium aluminate or with lime and calcium aluminate, then performing calcification dealkalization transformation in a high-concentration alkali liquid with the caustic alkali concentration of 100-300 g/L, converting silicon-containing phases in the red mud totally into the form of hydrate garnet to enter calcified slag generated during the dealkalization process, carbonizing the calcified slag to obtain carbonized slag, then performing low-temperature aluminum dissolution and aluminum precipitation to obtain a calcium aluminate product, and returning the calcium aluminate to the red mud calcification dealkalization transformation process for recycling. Some alkali and aluminum-containing liquid phases subjected to calcification dealkalization transformation can be reused as supplement alkali during the Bayer production process. The method can realize recycling of alkali and aluminum in the red mud and harmless treatment of the Bayer red mud, and is an energy-saving and environmentally-friendly red mud utilization method.