Scientific grounds and prospects for closed-circuit processing of alumina-containing raw materials with the decomposition of salt and acid-salt types

摘要

A brief overview and critical analysis of acid and acid-salt methods for processing alumina raw materials, including high-silica bauxite, nepheline and clay is presented.The basic approaches to the creation of closed and reagent-less or low-reagent-consumption processes are demonstrated.The results obtained in the course of long-term systematic laboratory and bench studies carried out in the "NewChem Technology" Company are presented, and they display the prospects for the creation of new technologies for the production of alumina from high silica bauxite and aluminum silicates with the use of different nitrate and sulfate reagents.In the case of using acids, the method of "acid retardation" in nano-porous media is shown to be successfully used for recycling them into the process head and to ensure soft conditions for the removal of iron components.A circular process with the recovery and consumption of the same amount of salt reagent in each cycle is demonstrated.A comparison of digestion methods is given in terms of the completeness of reagent recycling, the quality of product and the complexity of the process.Advisable conditions for the production of alumina from non-traditional raw with salt-acid decomposition are shown.