Mechano-chemical activation of kaolin minerals

Juhász Zoltán: Mechano-chemical activation of kaolin minerals. In: Acta mineralogica-petrographica, (24). pp. 121-145. (1980)

[thumbnail of mineralogica_024_suppl_121-145.pdf]
Cikk, tanulmány, mű

Download (1MB) | Preview


Tests have been made to study processes during the intensive grinding (supergrinding) as mechanical activation of kaolins. Activation was made by dry grinding for different times in a vibrating mill. Conclusions: 1. Change of the inner morphology of kaolin powders is due to three partial processes: disintegration, aggregation and agglomeration. The first one prevails for a short activation time, the latter two being overwhelming in prolonged activation. Therefore the grade of dispersity initially grows to decrease after prolonged grinding. In this latter case, compacted aggregates result, inacessible to soaking in water, even if a peptizer is added. Also plasticity of the kaolin-water system decreases. 2. Supergrinding also affects the mutual adhesion, adsorption properties and action exchange capacity of kaolin particles as well as the acid solubility of kaolins very much. Test data hint to surface activation. At the same time, surface active centres will be covered by neighbouring particles ("overlapping effect"). 3. Supergrinding causes amorphization of the crystal structure, beside appearance of fireclay structure. Amorphization is bound to a critical crystallite size, and has different rates along each crystallographic direction. 4. Destruction of the crystal structure of kaolinite is concomitant to.the release of water of structural OH groups followed by incorporation of water into a gel structure. Xerogel when heated yields stable phases at the sáme high temperature as the original kaolinite. The high-temperature sintering process is, however, somewhat different in the two materials. 5. Mechano-chemical processes are somewhat accessible to artificial influencing by preliminary ion exchange."

Item Type: Article
Journal or Publication Title: Acta mineralogica-petrographica
Date: 1980
Volume: 24
ISSN: 0365-8066
Page Range: pp. 121-145
Language: English
Publisher: University of Szeged, Department of Mineralogy, Geochemistry and Petrology
Place of Publication: Szeged
Event Title: International Kaolin Symposium (10.) (1979) (Budapest)
Related URLs:
Uncontrolled Keywords: Kőzettan, Ásványtan, Földtan
Additional Information: Bibliogr.: p. 144-145. ; összefoglalás angol nyelven
Subjects: 01. Natural sciences
01. Natural sciences > 01.05. Earth and related environmental sciences
Date Deposited: 2016. Oct. 17. 09:25
Last Modified: 2022. Jul. 25. 13:08

Actions (login required)

View Item View Item