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The x-ray identification and crystal structures of clay minerals

01 Jan 1961-
About: The article was published on 1961-01-01 and is currently open access. It has received 966 citations till now. The article focuses on the topics: Clay minerals.
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Journal ArticleDOI
TL;DR: In this article, the crystallization behavior and phase relations in gel-derived alumina and alumina-zirconia ceramics have been investigated, and the implications of microporous gel structures on the modification of microstructures in these gel-based aluminina-ceramics are discussed.
Abstract: The crystallization behaviour and phase relations in gel-derived alumina and alumina-zirconia ceramics has been investigated. Zirconia was found to form a limited metastable solid solution with the alumina matrix. When present in solid solution, zirconia phase appeared to enhance rapid growth of corundum grains. There was no apparent grain refinement in the alumina-zirconia composites. The implications of microporous gel structures on the modification of microstructures in these gel-derived ceramics are discussed.

41 citations

Journal ArticleDOI
TL;DR: In this paper, the average interlayer material approximated in composition to [Al(OH)2]- and [Mg(OH)]+ with additions of NaOH the interlayer compositions moved progressively towards Al(OH)-3 and Mg-OH 2.
Abstract: Hydroxy-Al- and hydroxy-Mg-montmorillonite were prepared by treating dispersed Na-montmorillonite with aluminum and magnesium nitrate solutions and titrating with NaOH solutions so that the OH/A1 ratio varied from zero to 3.0 and the OH/Mg ratio from zero to 2.0. External precipitation of Al and Mg hydroxides was observed when the OH/M ratios (M = metal) approached 3 and 2, respectively. From chemical analyses of the initial Na-montmorillonite and the hydroxy-metal montmorillonites, structural formulae were derived by assuming that the silicate layer compositions remained unchanged. Prior to the addition of NaOH, the average interlayer material approximated in composition to [Al(OH)2]+ and [Mg(OH)]+. With additions of NaOH the interlayer compositions moved progressively towards Al(OH)3 and Mg(OH)2. When the hydroxy interlayers approached completion, external precipitation was observed. X-ray powder diffraction data showed that the hydroxy-Mg products have less tendency to swell in ethylene glycol and water, and greater thermal stability than the hydroxy-Al products. Initially, when the average interlayer compositions were near Al(OH)2 and Mg(OH), swelling followed more nearly the normal behavior.

41 citations

Journal ArticleDOI
01 Dec 1984-Geoderma
TL;DR: Weathering of meta-dolerite by alteration of hornblende, plagioclase feldspars and chlorite occurs in a West Australian saprolite.

41 citations

Journal ArticleDOI
TL;DR: In this paper, spherical calcium alginate based hybrid (CAH) composites were used as adsorbents for the removal of total organic acid anions (TOA) as heat stable salt (HSS) and heavy metal ions (chromium and iron) from industrial lean methyldiethanolamine (MDEA, 50 wt%) solvents.

41 citations

Journal ArticleDOI
TL;DR: The late-precambrian Torridonian sediments of the Cape Wrath district, extreme north-west Scotland, unconformably overlie a planar, weathered Lewisian surface.
Abstract: Synopsis The late-Precambrian Torridonian sediments of the Cape Wrath district, extreme north-west Scotland, unconformably overlie a planar, weathered Lewisian surface. The weathered profile present beneath the unconformity is regarded as Torridonian in age, and hence must rank with the oldest palaeosols in the world. This planar surface was partly stripped of its mantle of altered rock prior to burial beneath Torridonian alluvial fan deposits. Where developed on biotite-gneiss, the weathered profile has the chemical characteristics of a modern pedalfer. A pedocal-type soil developed on amphibolite. The chemical and mineralogical changes are suggestive of a warm, moderately humid climate, possibly with dry periods or a dry season. A similarly weathered Lewisian terrain could, in principle, have supplied the bulk of the overlying Torridonian sediments.

40 citations