Organic and Inorganic Dispersion of Alumina

Sundlof, B.; Carty, William M.

doi:10.1002/9780470294543.ch15

Cited by 3 publications

(2 citation statements)

References 3 publications

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“…There is a report [11] that the structure of the substance changes from gibbsite structure to boehmite structure, and in this study, it is reconfirmed that similar structural change happens when the substance is calcined at around 400…”

Section: Resultssupporting

confidence: 71%

Structure Transformation of Gibbsite by Calcination

Ogata

Kawasaki

Kabayama

et al. 2006

e-J. Surf. Sci. Nanotechnol.

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Gibbsite, which is aluminum oxide, was calcined in the temperature range from 200 to 1150• C, and the relation between the calcination temperature and various properties of gibbsite has been examined. It is speculated based on the results of TG-DTA experiment that the structure of gibbsite changed greatly at a calcination temperature of 282.7• C. Specific surface area of gibbsite kept on increasing as the calcination temperature is elevated up to 400• C, where it reached a maximum value. In the range where the calcination temperature is higher than 400• C, specific surface area decreased as the temperature was elevated further. In addition, it became evident from the results of XRD measurement that in the calcination temperature range lower than 200• C, the crystal kept gibbsite structure, but it changed to the structure of aluminum oxide of transition type above 300• C, and that it changed further to the structure of stable aluminum oxide when the calcination temperature was elevated over 1000• C. From these results, it is verified that by making use of the fact that the structure of gibbsite changes greatly in the calcination temperature range from 300 to 400• C, a novel adsorbent having boehmite structure can be produced.

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Section: Resultssupporting

confidence: 71%

Structure Transformation of Gibbsite by Calcination

Ogata

Kawasaki

Kabayama

et al. 2006

e-J. Surf. Sci. Nanotechnol.

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“…1 and it is often reported as a dispersant for fine particles. [7][8][9][10][11] Metaphosphates are in general used in flotation for a number of functions such as depressing clay and fine particles and softening water, 12 depressing iron sulfides during coal flotation, 13 and depressing alkaline earth minerals during the flotation of beryllium ores 14 and tungsten ores. 12 They were also found as selective depressants for the carbonate gangues in the flotation of pyrochlore from carbonatite niobium ores.…”

Section: Introductionmentioning

confidence: 99%

Adsorption behaviour of sodium hexametaphosphate on pyrochlore and calcite

Liu

2013

Canadian Metallurgical Quarterly

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FTIR, XPS and zeta potential measurements were performed on pyrochlore and calcite to study the adsorption mechanisms of sodium hexametaphosphate (NaHMP). While no hexametaphosphate could be detected on the FTIR spectra of NaHMP treated pyrochlore or calcite, the observed chemical shifts of the binding energies of Ca 2p 5/2 (0?25 eV) and P 2p (0?20 eV) electrons indicated that the hexametaphosphate groups formed a complex with calcium on calcite. The complex seemed soluble in water leaving a low concentration of its residue on calcite surface after water washing, thus undetectable by FTIR. The binding energy shifts of Nb 3d 5/2 (0?13 eV) and Ca 2p 5/2 (0?10 eV) electrons on NaHMP-treated pyrochlore were within instrumental resolution, therefore, NaHMP was not strongly bound to pyrochlore. The zeta potentials of pyrochlore and calcite were both lowered in the presence of NaHMP. However, for pyrochlore, the zeta potential drop occurred mainly in the acidic pH range, while the drop for calcite was independent of pH, indicating possible chemisorption of NaHMP on calcite. The work explained the selective depressive function of NaHMP in the hydroxamic acid flotation of carbonatite niobium ores.On a effectué des mesures de FTIR, de XPS et de potentiel zê ta du pyrochlore et de la calcite afin d'é tudier les mé canismes d'adsorption de l'hexamé tahosphate de sodium (NaHMP). Bien qu'on ne puisse pas dé tecter d'hexamé taphosphate dans les spectres de FTIR du pyrochlore ou de la calcite traité s au NaHMP, les dé calages chimiques observé s des é nergies de liaison des électrons de Ca 2p 5/2 (0?25 eV) et de P 2p (0?20 eV) indiquaient que les groupes d'hexamé taphosphate formaient un complexe avec le calcium sur la calcite. Le complexe semblait soluble dans l'eau, laissant une faible concentration de son ré sidu à la surface de la calcite aprè s lavage à l'eau, donc indé tectable par FTIR. Les dé calages de l'é nergie de liaison des é lectrons du Nb 3d 5/2 (0?13 eV) et du Ca 2p 5/2 (0?10 eV) du pyrochlore traité au NaHMP se situaient dans les limites de ré solution de l'instrument. Donc, le NaHMP n'é tait pas fortement lié au pyrochlore. Les potentiels zê ta du pyrochlore et de la calcite s'abaissaient tous deux en pré sence de NaHMP. Cependant, la chute de potentiel zê ta du pyrochlore se produisait principalement dans la gamme de pH acide, alors que la chute pour la calcite é tait indé pendante du pH, indiquant la possibilité d'une chemisorption du NaHMP sur la calcite. Ce travail explique la fonction sé lective et dé pressive du NaHMP lors de la flottation à l'acide hydroxamique des minerais de carbonite de niobium.

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Elaboration and Physico-Chemical Characterization of the Gibbsite Li(OH)3 Hybrid Material

Belkham

Benachour

Mehamha³

2021

Eng. Technol. Appl. Sci. Res.

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A hybrid material can be defined as a combination of two components of different chemical nature. The combination of a mineral matrix and organic matter has multiple significance. From a chemical point of view, it allows the obtaining of bi-functional materials that combine the chemical properties of their components. The development of new materials with specific properties and nanostructured Lamellar Double Hydroxides (LDHs) has been widely investigated due to their great importance. This study focuses on the development of a hybrid material consisting of a matrix of alumina trihydrate Al(OH)3 (gibbsite). Previous studies on the synthesis of suspension LDHs by lithium salts intercalation in a gibbsite matrix were examined, while the obtained samples were characterized by different physicochemical methods.

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Organic and Inorganic Dispersion of Alumina

Cited by 3 publications

References 3 publications

Structure Transformation of Gibbsite by Calcination

Structure Transformation of Gibbsite by Calcination

Adsorption behaviour of sodium hexametaphosphate on pyrochlore and calcite

Elaboration and Physico-Chemical Characterization of the Gibbsite Li(OH)3 Hybrid Material

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