EXTRACTION OF ALUMINIUM BY AUTOCLAVE HYDROCHLORIC ACID LEACHING OF BOEHMITE-KAOLINITE BAUXITE

摘要

In this paper we investigate the process of autoclave extraction ofrnboehmite-kaolinite bauxite for Severoonezhsk deposits byrnhydrochloric acid. The effect of temperature and duration of thernprocess on transition of aluminum into solution has been studied.rnThe apparent activation energy was defined for the process. Therninfluence of hydrochloric acid concentration on alumina transitionrnin solution was shown. Determined the apparent degree of thernprocess on reagents. The obtained results allow to allocate 3rnlimiting stages of the process: 150 – 160℃ – a chemical reactionrn(Е_а = 70.88 kJ/mol), 160 – 170℃ – intermediate region (Еа =rn40.22 kJ/mol), 170 – 180℃ – diffusion area (Е_а = 22.66 kJ/mol).rnThermodynamic modeling of physicochemical processesrnunderlying the preparation of aluminum containing solutions hasrnbeen performed. It has been demonstrated that the majorrnaluminum species in solution are aluminum chlorides andrnhydroxychlorides.