Abstract
A new roasting process with a conveying bed was constructed and used to remove sulfur of high-sulfur bauxite. Roasting temperature, phase transformation, microcrystal, specific surface area of high-sulfur bauxite, and the mechanism of the reaction during the roasting process were analyzed. The digestion properties of roasted bauxite were also investigated. The results showed that the sulfur in high-sulfur bauxite can be efficiently removed by roasting in the conveying bed at 520–720 °C for 2 s. Major reactions of high-sulfur bauxite during roasting were the dehydration of minerals, desulfurization of pyrite, sulfation of SO2, and decomposition of sulfate. The rate of mineral dehydration reaction was significantly slower than that of the desulfurization reaction. The specific surface area of roasted ore greatly increased, and the microcrystal of Al-O mineral was refined, which was conducive to Al2O3 digestion. The mass fraction of sulfide sulfur in high-sulfur bauxite was reduced from 1.20% to 0.01%, and the relative digestibility of alumina reached more than 99% when roasting at 600 °C for 2 s. This paper provides revelations and instructions for the process development and application of high-sulfur bauxite.
Highlights
Bauxite, the main raw material for aluminum production, is rapidly consumed with the development of modern industry
The proposed method is effective for the desulfurization of high-sulfur bauxite by the new conveying bed roasting process
The mass fraction of sulfide sulfur in the roasted ore can be reduced to 0.01%, and the relative digestibility of alumina can reach more than 99%
Summary
The main raw material for aluminum production, is rapidly consumed with the development of modern industry. Major desulfurization methods of high-sulfur bauxite are floatation desulphurization, roasting desulphurization, and desulphurization in the digestion process. Studies have examined dense‐phase roasting, for instance, rotary kiln and fluidized beds, where high sulfur bauxite should be treated at 750°C minimum for at least 10 min [17,18,19,20,21,22]. Gestion properties of raw ore and roasted ore were analyzed and compared via digestion In this paper, the thermal reaction characteristics of high sulfur bauxite were analyzed experiment. A semi-industrial conveying bed device was constructed was expounded via sulfur phase analysis, XRD, SEM, and a specific surface area test. For roasting desulfurization experiments of high sulfur bauxite, and the relationship besults confirmed that the new roasting process with a conveying bed was effective for roast‐.
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