A study on the preparation of fine and low soda alumina

Park, Yi Yong; Lee, Suong Oh; Tran, Tam; Kim, Seong Jun; Kim, Myong Jun

doi:10.1016/j.minpro.2006.03.006

Cited by 13 publications

(3 citation statements)

References 11 publications

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“…The grain morphology was similar with that of activated alumina reported in ref. [14]. The EDS analysis shows that the grains on Cu-5Al alloy surface contained mainly Al and O elements besides a portion of Cu element.…”

Section: Resultsmentioning

confidence: 93%

Oxidation Resistance and Plating Encapsulation of Cu-Based Alloys as Phase Change Materials for High-Temperature Heat Storage

Zhang

Qian

et al. 2013

KEM

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Cu-based alloys have been regarded as one of the most promising phase change materials (PCMs) in industrial waste heat recovery and solar thermal electric generation. In this paper, the oxidation behavior and the containment of liquid Cu were investigated. It was found that with the small addition of aluminum, the oxidation resistance of Cu-based PCMs was greatly enhanced. Notably, its latent heat density remained high. The containment of PCMs was achieved by depositing a Ni-base exterior coating on Cu spheres through barrel plating, rack plating and electroless plating processes. The deposition rates, surface topography, and the crystallography of the coatings depended largely on the plating process. The cyclic thermal was tested at last.

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Section: Resultsmentioning

confidence: 93%

Oxidation Resistance and Plating Encapsulation of Cu-Based Alloys as Phase Change Materials for High-Temperature Heat Storage

Zhang

Qian

et al. 2013

KEM

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“…The chemical analysis of the samples was obtained using XRF (Philips PW 1480 spectrometer). In the Bayer process, gibbsite is produced by precipitation from sodium aluminate solution so the gibbsite, and alumina obtained from the calcination of the gibbsite, contains a considerable amount of sodium impurity (expressed as %Na 2 O in product chemical analysis) (Park et al 2006; Carter and Norton 2007). The received sample of gibbsite was first washed in distilled water while stirring, dried at 110°C for 3 h, then for further reduction of impurities, particularly sodium, the sample was washed in hydrochloric acid solution (HCl, 38% purity, Merck Co, Germany) with stirring and dried at 110°C for 3 h. The chemical composition of the treated gibbsite was: 99.58% Al(OH) 3 , 0.08% SiO 2 , 0.07% Fe 2 O 3 , 0.04% CaO and < 0.1% Na 2 O.…”

Section: Methodsmentioning

confidence: 99%

The relation between particle size and transformation temperature of gibbsite to αLPHA-alumina

Ahmadabadi

Nemati

Arzani

et al. 2020

Mineral Processing and Extractive Metallurgy

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The transformation of gibbsite to α-alumina occurs in the range 1100 to 1300°C. The higher the calcination temperature, the larger the crystallites and this leads to abnormal grain growth. The main goal of this research was to reduce the transformation temperature of gibbsite to αalumina by reducing the gibbsite particles size. The sodium content of the gibbsite used in the study was reduced to less than 0.1% by washing it in HCl solution. It was then ground in a fast mill at ambient conditions for different times then calcined at different temperatures. The microstructure, particles size and thermal behaviour of the samples were examined with SEM, XRD, XRF, PSA and STA, respectively. In a sample ground for 180 min, the transformation temperature decreased from about 1300°C to 1150°C. The reduction in the calcination temperature led to a reduction in α-alumina crystallite size from about 77.16 nm to 64.37 nm.

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“…Low soda alumina is generally defined as an alumina hydrate with soda content of less than 0.1% by weight. This can be manufactured by many different routes, including acid washing, chlorine addition, boron addition, and the use of soda adsorbing compounds [75][76][77].…”

Section: Commercial Types Of Alumina Productsmentioning

confidence: 99%

Short review on mechanical activation in non-metallurgical alumina production

Kim¹,

Dobra²,

Isopescu³

et al. 2022

RJEEC

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The terms mechano-chemistry and mechanical activation of solid materials were introduced in chemical literature by Ostwald at the beginning of the XX century. Both terms cover a whole range of interconnected phenomena taking place during the mechanical action on solids or their separate parts participating in chemical reactions, phase transitions, mixing and creating composite materials, alloying and crystal growth in the solid state, deformation and changing physical and thermal properties, all of them at low temperature. The common effects of the mechanical activation on solid material are fracturing and reduction of particle sizes, generation of new reactive surfaces, diffusion of atoms of the reactant phase through the product phase, and quite significantly, accumulating energy in crystalline or amorphous structure (enough twists in atomic and molecular networks, tensions in atomic bond and active sites to trigger the nucleation of new phases). Mechanical activation is very used to produce all clean alumina mineralogical phases with uniform particle size dimensions from nano to macro size. Also, mechanical activation may extend the specific surface of some minerals, enhancing the yields in the solid-liquid extraction process. With adequate precursors, all phase transitions from amorphous to alfa α-Al2O3 can be carried out on the same route as in thermally activated alumina, but some other routes, impossible by thermal activation, might be followed. The difference between the two activation ways is that mechanical activation is made at room temperature.

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A study on the preparation of fine and low soda alumina

Cited by 13 publications

References 11 publications

Oxidation Resistance and Plating Encapsulation of Cu-Based Alloys as Phase Change Materials for High-Temperature Heat Storage

Oxidation Resistance and Plating Encapsulation of Cu-Based Alloys as Phase Change Materials for High-Temperature Heat Storage

The relation between particle size and transformation temperature of gibbsite to αLPHA-alumina

Short review on mechanical activation in non-metallurgical alumina production

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