Synthesis and Characterization of Boehmites Obtained from Gibbsite in Presence of Different Environments

Filho, Ricardo Wilson Nastari Denigres; Rocha, Gisele de Araujo; Montes, Célia Regina; Coelho, A. C. Vieira

doi:10.1590/1980-5373-mr-2016-0019

Cited by 44 publications

(18 citation statements)

References 60 publications

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“…However, some amorphous phases with variable concentrations in the phase mixtures were found in all samples. The results are in accordance with literature studies [41,59,60]. Each chemical and phase transformation that generates the overlapping endothermic effects is firmly influenced by the experimental parameters, such as heating rate, water vapor pressure, and particle dimension.…”

Section: Resultssupporting

confidence: 91%

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Thermally Activated Al(OH)3 Part II—Effect of Different Thermal Treatments

Vasile

Dobra²,

Iliev

et al. 2021

Ceramics

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In this paper, the thermal decomposition of crystalline Al(OH)3 was studied over the temperature range of 260–400 °C for particles with a size between 10 and 150 µm. The weight losses and thermal effects occurring in each of the dehydration process were assessed using thermogravimetry (TG) and differential scanning calorimetry (DSC) thermal analysis. X-ray diffraction (XRD) patterns, refined by the Rietveld method, were used for mineral phase identification, phase composition analysis, and crystallinity degree determination. Moreover, the particle size distributions and their corresponding D10, D50, and D90 numeric values were determined with a laser analyzer. We observed a strong relationship between the calcination temperature, the initial gibbsite grade particle size, and the crystallinity of the resulting powders. Hence, for all endothermic effects identified by DSC, the associated temperature values significantly decreased insofar as the particle dimensions decreased. When the gibbsite was calcined at a low temperature, we identified small amounts of boehmite phase along with amorphous new phases and unconverted gibbsite, while the powders calcined at 400 °C gradually yielded a mixture of boehmite and crystalized γ-Al2O3. The crystallinity % of all phase transition products declined with the increase in particle size or temperature for all the samples.

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Section: Resultssupporting

confidence: 91%

“…However, some amorphous phases with variable concentrations in the phase mixtures were found in all samples. The results are in accordance with literature studies [41,59,60].…”

Section: Gdah-05supporting

confidence: 93%

Thermally Activated Al(OH)3 Part II—Effect of Different Thermal Treatments

Vasile

Dobra²,

Iliev

et al. 2021

Ceramics

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“…Two more endotherms occur at 265°C and 310°C and correspond to mass losses of 5.1% and 27 21.1%, respectively. The second of these endotherms can be attributed to the formation of boehmite or a boehmite-like structure, which should give a theoretical mass loss of 23.1% 69 .…”

Section: Thermal Stabilitymentioning

confidence: 99%

Boehmite and Gibbsite Nanoplates for the Synthesis of Advanced Alumina Products

Zhang

Huestis

Pearce

et al. 2018

ACS Appl. Nano Mater.

117

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Boehmite (γ-AlOOH) and gibbsite (α-Al(OH) 3 ) are important archetype (oxy)hydroxides of aluminum in nature that also play diverse roles across a plethora of industrial applications. Developing the ability to understand and predict the properties and characteristics of these materials, on the basis of their natural growth or synthesis pathways, is an important 1 fundamental science enterprise with wide ranging impacts. The present study describes bulk and surface characteristics of these novel materials in comprehensive detail, using a collectively-sophisticated set of experimental capabilities, including a range of conventional laboratory solids analyses and national user facility analyses such as synchrotron X-ray absorption and scattering spectroscopies, as well as small angle neutron scattering. Their thermal stability is investigated using in situ temperature-dependent Raman spectroscopy. These pure and effectively defect-free materials are ideal for synthesis of advanced alumina products.

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“…The dissolution of the silica and silicic acid disrupts the chemical content of kaolinite. Bauxitic kaolinite transforms into gibbsite, boehmite, or diaspore under the influence of depth and temperature [22], [64], [65]. In regions with high groundwater levels and regular precipitation conditions, gibbsite is more stable than boehmite mineral in bauxite ore. On the other hand, in regions with low groundwater levels and irregular precipitation conditions, boehmite mineral is more stable than gibbsite [66].…”

Section: Mineral Genesismentioning

confidence: 99%

Geochemical characterization of the Sutlegen bauxite deposit, SW Antalya

Atakoglu¹,

Yalçın²

2021

Min. miner. depos.

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Purpose.The purpose is to determine geological and geochemical characteristics of the Sutlegen (Antalya, Turkey) bauxites, to identify the elements that played a major role in their formation. Methods. X-ray diffraction (XRD) mineral phase analysis, X-ray fluorescence (XRF) elemental analysis, plasma-mass spectrometry (ICP-MS), the petrographic and mineralogical analyses, and multivariate statistical methods were used. Findings. The major element content of the ore was determined as Al2O3 (60-35.2 wt%), SiO2 (39.5-0.2 wt%), Fe2O3 (48.4-19.5 wt%), TiO2 (36.9-16 wt%), and P2O5 (0.5-0.1 wt%). The Sutlegen region, which shows epirogenetic action with the uplift of the earth's crust, is generally rich in neritic carbonates. It was revealed that the bauxite ores have undergone moderate and strong laterization as a result of the deferruginization in the environment, and they were classified into four groups as lateritic, ferritic, kaolinitic, and bauxite. The increase in the aluminosilicate minerals, which were formed during the formation of bauxite in the environment was found to be directly proportional to the laterization processes. In this context, it was considered that the lateritic material that was firstly formed in the environment filled the cavities and pores of the karst-type limestones and sedimentary units in the region by superficial transfer phenomena. The bivariate diagrams of Log Cr vs. Log Ni revealed that the bauxite that formed in the region had an ultrabasic source. Originality. In literature, no scientific studies have been found on bauxite mineralization in the Sutlegen deposits that have been operated for a long period. Practical implications. In this context, the geochemical characteristics of bauxites revealed that the source of the laterization process in the region was the ultrabasic igneous rocks. The lateritic material moved by superficial transfer was accumulated on sandstone, claystone, siltstone, and limestone and in karstic cavities; then, it formed karstic bauxite (kaolinitic and bauxite) of different classifications due to the effect of metamorphism.

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Synthesis and Characterization of Boehmites Obtained from Gibbsite in Presence of Different Environments

Cited by 44 publications

References 60 publications

Thermally Activated Al(OH)3 Part II—Effect of Different Thermal Treatments

Thermally Activated Al(OH)3 Part II—Effect of Different Thermal Treatments

Boehmite and Gibbsite Nanoplates for the Synthesis of Advanced Alumina Products

Geochemical characterization of the Sutlegen bauxite deposit, SW Antalya

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