Feasibility Assessment for Leucosapphire Production from Aluminum Oxide Prepared Electrochemically

Nalivaiko, Anton Yu.; Лысенко, А. П.; Pak, V. I.; Иванов, М. А.

doi:10.1007/s11148-018-0186-4

Cited by 4 publications

(2 citation statements)

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“…At 1000 °C there was a transition to θ-Al 2 O 3 and α-Al 2 O 3 . These results were comparable to previous studies [28,29]. As can be seen in Table 5 and Figure 7, an increase in the calcination temperature above 900 °C led to a decrease in the chlorine content of the final product, but at the same time promoted the transition of γ-Al 2 O 3 to α-Al 2 O 3 , which negatively affected the dissolution of the resulting alumina during electrolysis of aluminum.…”

Section: Resultssupporting

confidence: 91%

Obtaining Alumina from Kaolin Clay via Aluminum Chloride

et al. 2019

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A method of alumina production based on hydrochloric acid processing of kaolin clays from the East Siberian deposits was studied. Hydrochloric acid leaching was carried out at 160 °C. The leaching solution was subjected to a two-stage crystallization of aluminum chloride hexahydrate (ACH). The precipitated crystals were calcinated in air at a temperature above 800 °C to produce alumina. The main part of water and chlorine during thermal decomposition of ACH was removed at 400 °C. The influence of temperature and duration of ACH calcination on the residual chlorine content in alumina was studied. The optimal temperature of ACH calcination was 900 °C with a duration of 90 min. It was shown that the increase in calcination temperature contributed to the decrease in chlorine content in the final product. However, an increase in calcination temperature above 900 °C led to the transition of the well-soluble γ-Al2O3 phase to the insoluble α-Al2O3, which negatively affected the further electrolysis of aluminum. The size of alumina particles was not affected by the calcination mode. The rate of dissolution of the prototype Al2O3 in Na3AlF6 was higher than for the alumina obtained by the classical method. Alumina content, particle morphology, and particle size distribution for the obtained alumina were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and laser diffraction methods. The obtained alumina is suitable for aluminum production according to the studied characteristics.

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Section: Resultssupporting

confidence: 91%

Obtaining Alumina from Kaolin Clay via Aluminum Chloride

et al. 2019

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“…The oxidation of nano- and micron-sized aluminum powders by water is widely studied [22,23,26,27,28,29,30,31,32,33]. The majority of publications [22,28,29,30,31,34] dealt with the different points of obtaining hydrogen by the reaction of aluminum with water.…”

Section: Introductionmentioning

confidence: 99%

Aluminum-Alumina Composites: Part I: Obtaining and Characterization of Powders

et al. 2019

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The process of advanced aluminum-alumina powders production for selective laser melting was studied. The economically effective method of obtaining aluminum-alumina powdery composites for further selective laser melting was comprehensively studied. The aluminum powders with 10–20 wt. % alumina content were obtained by oxidation of aluminum in water. Aluminum oxidation was carried out at ≤200 °C. The oxidized powders were further dried at 120 °C and calcined at 600 °C. Four oxidation modes with different process temperatures (120–200 °C) and pressures (0.15–1.80 MPa) were investigated. Parameters of aluminum powders oxidation to obtain composites with 10.0, 14.5, 17.4, and 20.0 wt. % alumina have been determined. The alumina content, particle morphology, and particle size distribution for the obtained aluminum-alumina powdery composites were studied by XRD, SEM, laser diffraction, and volumetric methods. According to the obtained characteristics of aluminum-alumina powdery composites, they are suitable for the SLM process.

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