Acid and thermal treatments of lateritic bauxites

Mendelovici, E.

doi:10.1023/b:jtan.0000027189.10320.db

Cited by 10 publications

(5 citation statements)

References 14 publications

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“…Some studies have already shown that the iron oxide content in nonrefractory grade bauxite can be decreased by an acid leaching process. 5,[8][9][10][11][12][13][14][15][16][17][18][19][20] Hydrochloric acid (HCl) in particular seems to be attractive for this application. However, in order to determine the possible leaching success, extensive tests are necessary, since a large number of different parameters influence the leaching process and thus the amount of dissolved iron.…”

Section: Introductionmentioning

confidence: 99%

“…So it is all the more important to also be able to modify bauxite with an excessively high Fe 2 O 3 content usable for the refractory industry. Some studies have already shown that the iron oxide content in nonrefractory grade bauxite can be decreased by an acid leaching process 5,8–20 . Hydrochloric acid (HCl) in particular seems to be attractive for this application.…”

Section: Introductionmentioning

confidence: 99%

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Iron leaching from nonrefractory grade bauxite: Individual process optimization and prediction by using DOE

Stein

Sax

Quirmbach

2022

Int J Ceramic Engine & Sci

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Bauxite is an important raw material for the production of refractories. The availability of refractory grade ore worldwide is limited, and high iron contents in particular reduce the quality of the material. For refractory applications, a maximum iron content of 2 % is acceptable. In this study, acid leaching with HCl is used to decrease the iron content in different nonrefractory grade raw bauxites. Computerized design of experiments and statistical methods are used to determine optimum process parameters and influencing factors for different bauxites individually. Compared to previously published studies, the applied approach makes it possible to process even very iron-rich bauxites (e.g., 31 % Fe 2 O 3 in calcined substance) and to lower their Fe 2 O 3 contents below the permitted 2 %. In addition, larger grain sizes (around 5.5 mm) can be used. Statistical planning and mathematical modeling also allow the prediction of the minimum achievable iron content within the investigated parameter ranges. For selected parameter combinations, the achievable Fe 2 O 3 content can be predicted relatively accurately without the requirement for practical testing of the corresponding experimental setup.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Iron leaching from nonrefractory grade bauxite: Individual process optimization and prediction by using DOE

Stein

Sax

Quirmbach

2022

Int J Ceramic Engine & Sci

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“…In addition, hydrochloric acid leaching was used to remove the dolomite impurity from the flotation concentrate of a low-grade bauxite ore, improve its Al 2 O 3 grade and Al 2 O 3 /SiO 2 (A/S) ratio [6]. However, the extraction results of the acid treatments are influenced by the composition, mineralogy, and location of each ore [7]. Numerous studies show that the synchronous extraction of Al and Fe is difficult to achieve using acid treatments, which can only be used for the selective chemical dissolution of goethite (FeOOH) and gibbsite (Al(OH) 3 ) [8,9].…”

Section: Introductionmentioning

confidence: 99%

Semi-Smelting Reduction and Magnetic Separation for the Recovery of Iron and Alumina Slag from Iron Rich Bauxite

Gao

Zhao

et al. 2019

Minerals

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This work presents a semi-smelting reduction and magnetic separation process for the recovery of iron and alumina slag from iron rich bauxite ore. The effect of the process parameters on the recovery rate of iron, maximum particle size of the iron nugget, and the Al2O3 content of the alumina slag was investigated and optimized. The results show that the iron nuggets and alumina slag can be obtained in a short time through a semi-smelting reduction and magnetic separation process. The maximum particle size of iron nugget is about 15 mm, and the recovery rate of the iron and Al2O3 grade of the alumina slag are 96.84 wt % and 43.98 wt %, respectively. The alumina slag consisted mainly of alumina (α-Al2O3), calcium hexaluminate (CaAl12O19), gehlenite (Ca2Al2SiO7), and small amounts of hercynite (FeAl4O7), and metallic iron (M.Fe).

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“…Mineralogical and geochemical investigations of the bauxite in this region have been performed by several researchers [3][4][5][6][7][8][9][10]. Wei et al [11] investigated the source materials as well as the formation and evolution processes of two representative bauxite deposits and of terra rossa taken from this region, while Deng et al [12] demonstrated a genetic relationship between this deposit and the Emeishan plume via U-Pb and Lu-Hf isotope studies, in which the majority of the zircon e Hf (T) values were in the range of 256-261 Ma and were negative, varying widely from -1.3 to -16.1.…”

Section: Introductionmentioning

confidence: 99%

Mineralogical and thermal characteristics of low-grade Jinlong bauxite sourced from Guangxi Province, China

Wang

Xing

Zhang

et al. 2015

J Therm Anal Calorim

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Characteristic samples from the No. 1 ore body of the Jinlong bauxite deposit in Guangxi Province, China, were assessed to determine their chemical composition using whole-rock geochemical analysis, their mineral components using X-ray diffraction, their thermal characteristics via differential thermal analysis, thermogravimetry and differential thermogravimetry, and their dissemination characteristics by scanning electron microscopy/energydispersive spectrometry. The results show that the average Al 2 O 3 content in the Jinlong bauxite deposit is 41 % and that the Al 2 O 3 /SiO 2 ratio is approximately 2.17, and thus, the ore may be defined as low-grade bauxite. The main minerals found in the ore were diaspore (20.3-43 %), gibbsite, clays and hematite. In differential thermal analysis results, the bauxite samples exhibit two distinct endothermic peaks, with the dehydration of gibbsite occurring in the 200-260°C range and the dehydration of diaspore occurring in the 524-550°C range. Thermogravimetry and differential thermogravimetry indicate four decomposition stages: evaporation of adsorbed water (50-160°C), gibbsite decomposition (190-280°C), goethite decomposition (190-280°C) and diaspore dehydroxylation (460-580°C). The diaspore belongs to the orthorhombic dipyramidal class and exists primarily in three dissemination forms-euhedral and subhedral grain, bean and oolitic shaped, and aphanitic and microcrystalline aggregates, and is always accompanied by kaolinite and pyrophyllite.

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Acid and thermal treatments of lateritic bauxites

Cited by 10 publications

References 14 publications

Iron leaching from nonrefractory grade bauxite: Individual process optimization and prediction by using DOE

Iron leaching from nonrefractory grade bauxite: Individual process optimization and prediction by using DOE

Semi-Smelting Reduction and Magnetic Separation for the Recovery of Iron and Alumina Slag from Iron Rich Bauxite

Mineralogical and thermal characteristics of low-grade Jinlong bauxite sourced from Guangxi Province, China

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