| Autor: |
Najar, P. A. Mohamed, Dwivedi, Sneha, Karn, Amrita, Wadsariya, Shama, Nayar, Priyanka, Mahendiran, Periyasamy, Puttewar, Suresh, Agnihotri, Anupam |
| Předmět: |
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| Zdroj: |
Journal of Chemical Technology & Metallurgy; 2020, Vol. 55 Issue 5, p1156-1163, 8p |
| Abstrakt: |
Red mud is the largest solid waste generated during the Bayer process of alumina production. The bauxite quality and the processing conditions largely define the quantum of red mud generation. In general, 1 to 1.5 tons of red mud is generated during the production of 1 ton of alumina. The new approach to the red mud processing reported in this communication involves its pre-heat treatment with alkali at 400°C followed by acid leaching at an ambient temperature (25°C - 45°C). Polar solvents containing mineral acids are used for the selective dissolution of sodium, calcium, silica and alumina in the red mud aiming an indirect enrichment of iron and titanium. The heat energy released during the exothermic reaction involving sulphuric acid dissociation is used for triggering selective leaching of the red mud matrix major components. SiO2 is removed by hydrofluoric acid in the reaction mixture. Autogenous dissolution of red mud ensures the minimum energy consumption and the least toxic emissions during the selective dissolution of the mineral entities. The chemical analysis of the processed residue reports 80 % - 83 % of Fe2O3, 2 % - 3 % of Al2O3 and 1 % - 2 % of Na2O, SiO2 and CaO. An additional effort is made to use the treated residue as a precursor for a low-cost preparation of iron nanocomposites by auto combustion. The nanocomposite is chemically characterized, while the bulk to nano phase transformation of the material is verified by Scanning Electron Microscopy (SEM). [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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