Sedimentary kaolin

Carboniferous to Permian redbeds of the Pictou Group (Bell 1929). In the area surrounding the Bay of Fundy, there was also a Jurassic-Triassic sedimentary basin (Fundy Group) developed in which sandstones, shales, basalts and minor limestone were deposited. During the Cretaceous fluvial quartz sands and kaolin of the Chaswood Formation were deposited throughout the Maritimes, but only a few outliers have been preserved (Stea Pullan 2001). 

Kaolin clays are naturally occuring sedimentary deposits composed largely of kaolinite mineral. Typical impurities in these deposits are iron oxides, titanifer-ous minerals, silica, feldspar, mica, sulfides and organic matter. The majority of kaolin clay produced in the world is used in the paper industry as coating and filler materials. This mineral also makes an excellent filler, carrier, opacifier and diluent in a variety of industrial products such as paints, plastics, cement, rubber, pharmaceuticals, etc. 

The textures of kaolin (rockI include varieties similar to examples observed in igneous and melamorphic as well as sedimentary rocks. Kaolin grains and crystals may be straight or curved, sheaves, flakes, face-to-face or edge-to-edge flocculcs. interlocking crystals, tubes, scrolls, fibers, or spheres. 

Primary clay, known as kaolin, is found in the same place as the parent rock. Kaolin is formed by the weathering of feldspar. Kaolins are coarse in particle size and therefore nonplastic compared to most sedimentary clays. Kaolins are relatively free of mineral impurities such as iron. 

Smith, R.W., 1929. Sedimentary kaolins of the Coastal Plain of Georgia. GeoLSurv. Georgia, Bull., 44 482 pp. 

Is an agricultural grade of sedimentary kaolin having unusually fine particle size. Suspensions of CONTINENTAL Clay settle slowly and readily redisperse when shaken. Non-abrasive and non-alkaline, this clay is compatible with commonly used agricultural wetting and dispersing agents. 

A sedimentary kaolin, is used in adhesives, wall-board, paint, paper, fertilizer, roofing granules, crayons and powdered soaps. PEERLESS Clay is available in three grades according to fineness of particle size and color. 

Ball clay — a sedimentary kaolinic clay that fires to a white colour, highly plastic, with very fine particle size. 

Examples of inert or extender fillers include china clay (kaolin), talc, and calcium carbonate. Calcinm carbonate is an important filler, with a particle size of about 1 pm. It is a natural product from sedimentary rocks and is separated into chalk, limestone, and marble. In some cases, the calcium carbonate may be treated to improve interaction with the thermoplastic. Glass spheres are also used as thermoplastic fillers. They may be either solid or hollow, depending on the particular application. Talc is a filler with a lamellar particle shape. It is a namral, hydrated magnesium silicate with good slip properties. Kaolin and mica are also natural materials with lamellar structures. Other fillers include woUastonite, silica, barium sulfate, and metal powders. Carbon black is used as a filler primarily in the rnbber industry, but it also finds application in thermoplastics for conductivity, for UV protection, and as a pigment. Fillers in fiber form are often used in thermoplastics. Types of fibers inclnde cotton, wood flour, fiberglass, and carbon. Table 1.3 shows the fillers and their forms. An overview of some typical fillers and their effect on properties is shown in Table 1.4. Considerable research interest exists for the incorporation of nanoscale fillers into polymers. This aspect will be discussed in later chapters. 

Kaolins are classified as either primary or secondary. Primary kaolins are formed by the alterations of crystalline rocks such as granite. The source of this kaolin is found where it is formed. Conversely, secondary kaolin deposits are sedimentary and are formed by erosion of primary deposits. The secondary deposits contain much more kaolinite (about 85-95%) than the primary deposits, which contain only 15-30%. The balance of the ore consists of quartz, muscovite, and feldspar in the primary deposits and quartz, muscovite, smectite, anatase, pyrite, and graphite in the secondary deposits. Kaolin, also known by the common term clay, is usually open-pit mined in the United States from vast deposits in Georgia, South Carolina, and Texas. The ore is not processed in one singular way. There are also distinct methods of ore benefi-ciation, each adding value to the mineral. 

Calcium carbonate is an important filler with a particle size of about 1 p,m. It is a natural product from sedimentary rocks and is separated into chalk, limestone, and marble. In some cases the calcium carbonate may be treated to improve the bonding with the thermoplastic. Glass spheres are also used as thermoplastic fillers. They may be either solid or hollow, depending on the particular application. Talc is an important filler with a lamellar particle shape. It is a natural hydrated magnesium silicate with good slip properties. Kaolin and mica are also natural materials with lamellar stracture. Carbon black is used as a filler primarily in the rubber industry. 

Sedimentary rocks are derived from weathered rock masses and deposited by the action of water or other means, or by the sedimentation of bioliths (mineral skeletons, shells, etc., of plants and animals) into layers, or, rarely, by chemical precipitation. Massive deposits of china clay or kaolin are found as a result of weathering, followed by movement and deposition. Limestone, the general term for natural calcium carbonate rocks, is the most abundant of the sedimentary rocks and is formed by the deposition of countless skeletons and shells. Gypsum and diatomaceous earths occur widely in sedimentary rocks. Sedimentary rocks are almost universally found in layered beds, which may have folded or otherwise been altered by subsequent geological events. Layers will differ from each other in texture, mineralogy and particle size. 

Kaolin (Al2O3.2SiO2.2H2O), is probably more widely known as the clay mineral, china clay [11]. It is found in hydrothermal, residual and sedimentary deposits (probably about 1000 are still commercially worked) around the world with the most important resources being in Cornwall in SW England and in South Carolina and Georgia in the USA. Large... 

Hydrothermal and residual deposits are classified as primary occurrences, although some authorities call them secondary as they are found in the rocks from which they have been formed. Sedimentary deposits are always secondary. The kaolins are formed by the hydrothermal alteration and weathering of feldspathic igneous and metamorphic rocks (especially granite) under relatively low temperatures and pressures. The most common parent minerals are feldspars and muscovite micas. The primary deposits will usually be mixed with unaltered granite, mica, feldspar and quartz. Secondary deposits are usually found in layered qualities with very variable purity. 

In an art context, feldspars are found in sedimentary deposits such as ochres, kaolin (qq.v.) and clays. They can therefore occur as relict grains in artists materials based on these, they are found in particular as components of pottery of all ages as identified, for example, by Uda et al. (2000), Wopenka et al. (2002), Traore et al. (2000), Criado et al. (2002) and Shoval (1994). Feldspars have also been identified by S ichez-Moral et al. (2002) as present in cream mortars used in the cave site at Gaidar (Grand Canary Island). See individual feldspar entries for further details of uses as pigments. 

Most of the domestic supply of residual kaolin is obtained from western North Carohna, and most of the sedimentary clay comes from Georgia, South Carohna and Northern California. The South Carohna kaohns are widely used in the refractory and elastomeric industries. Although some of the South Carohna kaohn deposits have a naturaUy occurring large particle size which makes them excellent casting clays, most... 

Sedimentary (secondary) kaolin - In reference to geologie origin, the elay has been eroded and transported fix)m its site of formation and deposited at a distant location. The world s major kaolin belt, the 250 miles between Aiken, SC and Eufala, AL, consists of sedimentary kaolin. 

A clay-sized trioctahedral kaolin mineral, which occurs frequently in sedimentary ironstone deposits and marine mudstones and hence may occur in soils derived therefrom, has been... 

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