Dehydration， Decarburization and Digestion Performance of Gibbsitic Bauxite by Low-Temperature Roasting

doi:10.12068/j.issn.1005-3026.2023.07.005

Abstract

Abstract: The gibbsite bauxite pretreated by low-temperature roasting， the effects of roasting temperature and time on the dehydration and decarbonization of gibbsite ore and the digestion performance of calcined alumina were systematically studied by means of XRF， XRD and SEM. The results show that the ore quality greatly reduces after roasting and the obvious cracks are observed on the ore surface with lamellar structures. The gibbsite phase decreases and gradually changes to the boehmite， while the goethite changes to the hematite. When the roasting temperature is 400℃ and the roasting time is 30min， the mass fraction of crystal water in the ore is 7.54%， the dehydration ratio is 62.52%， the mass fraction of carbon is down to 0.11%， and the decarbonization ratio is 85.73%. When the digestion temperature of calcined ore is 145℃， the digestion time is 30 min， the mass concentration of circulating mother liquor caustic soda is 170g/L， and the actual digestion ratio of alumina is 81.51%， which is higher than that of the raw ore. The digestion kinetics results of calcined ore show that the digestion process of alumina is mainly controlled by internal diffusion， and the apparent activation energy is 42.71kJ/mol.

Key words: gibbsite; low-temperature roasting; dehydration; decarburization; digestion

CLC Number:

TF821

YANG Hu， PAN Xiao-lin， WU Hong-fei， YU Hai-yan. Dehydration， Decarburization and Digestion Performance of Gibbsitic Bauxite by Low-Temperature Roasting[J]. Journal of Northeastern University(Natural Science), 2023, 44(7): 944-952.

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