Clay minerals kaolin

Kaolinite is a clay mineral, kaolin is clay, but these terms are often used as synonyms. The results obtained for kaolin and for kaolinite are presented together. Kaolinites converted into specilic form (Na-, Ca-) are also included. Collections of PZC and/or charging curves of kaolinite from different sources can be found in [2246-2248],... 

The radioactive chromium (51Cr) found in Columbia River sediments contaminated with effluent from a nuclear reactor facility was not released by the major cations of sea water or by 0.05 M CuS0424 . The results of previous work in this laboratory (New England Aquarium) showed that of the silver(I) and cadmium(II) adsorbed on the clay minerals kaolin and montmorillonite, in essentially deionized water, less than half was desorbed on mixing with sea water25 . One may postulate from results such as these that most of the heavy metals occluded within a complex organic... 

The adsorption of short-chain aliphatic alcohol molecules on to the clay mineral kaolin has been elucidated by considering the heterogeneous surface sites of the clay and the self-association of alcohol molecules in apolar decane solutions [28]. The adsorption isotherms are shown in Fig. 4. The isotherms of ethanol, propanol, and butanol are of L-type, showing large initial slopes that readily decrease with increasing alcohol concentration, while the isotherm of methanol appears as a step wise function. 

Fireclay Refractories. These products are made from clay minerals containing ca 17—45% AI2O2. Pure kaolin has the highest alumina content. 

The least compHcated clay minerals are the 1 1 clay minerals composed of one tetrahedral (T) layer and one octahedral (O) layer (see Fig. 1). These 1 1 clay minerals are also referred to as TO minerals. The TO package has a basal spacing (nominal thickness) of 0.7 nm (7 E) and they are commonly referred to as 7 E minerals. Kaolinite, the dioctahedral 1 1 mineral, has filling two of three octahedral sites, and serpentine [12168-92-2J, (Mg)3Si205(0H)4, the trioctahedral 1 1 mineral has filling all three octahedral sites. The kaolin minerals have limited substitution in the octahedral... 

Gangue minerals are composed of calcite, dolomite and silica and often contains clay minerals (i.e. kaoline, montmorillanite)... 

The principal lead oxide minerals include pyromorphite, wulfenite, mimetite and plum-bojerusite. Some galena is also present in this ore type. The principal gangue minerals include silicate, dolomite, siderite, ferohydrooxides and clay minerals. About 20% of the ore is represented by ultra-fine slime with an average size of K%0 = 12 pm. These slimes are composed of Fe-hydroxides, kaolin and slimes of plumbojerusite, rich in silver. 

The two types of clay mineral structures which are of interest in the present discussion are the expanding 2 1 structures (the smectites and vermiculites) and the 1 1 structures (the kaolins). 

A number of reagents containing oxide components are used in zeolite manufacture [19]. Silica is provided by addihon of sodium or other alkali silicate solutions, precipitated, colloidal, or fumed silica, or tetraalkylorthosihcate (alkyl = methyl, ethyl) and certain mineral silicates such as clays and kaolin. Alumina is provided as sodium aluminate, aluminum sulfate soluhon, hydrous aluminum oxides such as pseudo boehmite, aluminum nitrate, or aluminum alkoxides. Additional alkali is added as hydroxide or as halide salts, while organic amines and/or... 

Lim CH, Jackson ML, Koons RD, Helmke PA (1980) Kaolins Sources of differences in cation exchange capacity and cesium retention. Qays Clay Miner 28 223-229 Low PE (1981) The swelling of clay III Dissociation of exchangeable cation. Soil Sci Soc Amer J 45 1074-1078... 

Honjo, C., N. Kitamura, and K. Mihama (1954). A study of clay minerals by means of single crystal electron diffraction diagrams structure of tubular kaolin. 

Examples are the mica group (e.g., KMg3(OF[)2Si3A10io) of which biotite, (K(Mg,Fe)3(OH)2Sl3A10io) (Figure 1.55) and talc (Mg3(OFl)2Si40io) are members, and contains a sandwich of two layers with octahedrally coordinated cations between the layers and clay minerals such as kaolin, Al4(OH)8Sl4C3io. 

Clay minerals are widely used in the filler industry and the production of the various types has been described by Hancock and Rothon [85]. The products available range from unaltered kaolin to products produced by calcination. Kaolin deposits are widespread throughout the world. While simple clay minerals are extensively used as fillers in elastomers, their use in thermoplastics is more restricted and the principal products used are those obtained by calcination of ka-olinite. Thus metakaolinite finds application in PVC and silane treated calcined clay in polyamides. The production of these forms only is discussed below. 

Currently, the only biological barrier registered as a biochemical pest control agent is kaolin, a clay mineral [47]. Kaolin is a ubiquitous clay substance found in soils worldwide and consists of a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedra [Al2Si205(0H)4]. 

Periodically, these mixtures were centrifuged and an aliquot of the clay-free supemate taken for counting analysis. Two naturally-occurring clays were selected for the experiments one was labeled kaolin (for the mineral kaolinite) while the second was referred to as attapulgite (or polygorshite). Both were obtained from the Source Clay Mineral Repository (3) as standard clays representative of each class of clay and were used as received. Stable, colloidal suspensions of each were prepared by ultrasonically dispersing weighed quantities of each clay in triple-distilled water. 

Nonmetallic Minerals Clay, Talc, Kaolin, Fluorspar, Feldspar, Diatoma-ceous Earth, Fullers Earth, Perlite... 

High Alumina Clay Minerals. Several hydrated alumina minerals should be grouped with the clay minerals because the two types may occur so intimately associated as to be almost inseparable. Diaspore (a-AIO(OH)) and bochmitc (y-AIO(OH)). both AFOj H 0(AI Oi. 85% H 0. 15%) are Ihe chief constituents of diaspore clay, which may contain over 75% AhOj on the raw basis. Gibbsite, AliOj 3 HyO (AljOi. 65.4% HjO. 34.6%). and cliachite. the so-called amorphous alumina hydrate (much cliachite is probably cryptocryslalline), as well as Ihe monohydrates, occur in hauxile, bauxitic kaolin, and bauxitic clays. 

Attention will be focused on two clay mineral groups kaolin and montmorillonite. Both groups have layered structures consisting of parallel sheets of oxide and hydroxide ions coordinated to Si4+ and Al3+ ions (233). Differences in the arrangement of the sheets and in their chemical composition give rise to the division into two groups. Within each group are several minerals of similar structure and composition. 

Clay minerals are the most common inorganic constituents of coal and of the strata associated with coal seams. Many different clay minerals have been reported within and associated with coals, but the most common clay minerals are kaolinite and mixed-layer illite-montmorillonite. Kaolinite-rich clay is commonly found within and associated with coals in most of the coal basins of the world. They are generally called either tonstein or kaolin-tonstein. 

Figure 3.7. Phenanthrene sorption isotherms on (A) the whole Amherst peat soil humic acid, (B) montmorillonite and a montmorillonite-humic acid complex (5 1 ratio), and (C) kaolin-ite and kaolinite-humic acid complex (5 1 ratio). Insets in parts B and C are the respective isotherms presented on a linear scale. Reprinted from Wang, K., and Xing, B. (2005). Structural and sorption characteristics of adsorbed humic acid on clay minerals. J. Environ. Qual. 34, 342-349, with permission from the Soil Science Society of America.

Brindley, G.W., 1961b. Kaolin, serpentine and kindred minerals. In G. Brown (Editor), The X-Ray Identification and Crystal Structures of Clay Minerals. London Mineral. Soc., London, pp. 51-131. 

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