Kaolin types

Kaolin type Brightness, % Maximum soHds, % Median particle size, p.m Uses Relative cost... 

Calcium carbonate 16. Fuller s earth (kaolin-type clay)... 

Some Information on self-bound zeolites has been published.(S) Howell and Acara (6) have converted preformed aggregates of reactive kaolin-type clay, under appropriate conditions, directly to a zeolltlc phase. Metakaolln having a S1/A1 ratio of 1.0 was easily converted to zeolite A. Also,... 

Since LSX and A zeolite have the same overall chemical composition and both are constructed by linking sodallte cages, we postulated that preformed metakaolln could be converted directly to LSX. Several reports show that kaolin-type clays can be transformed to X- or Y-type zeolites having S1/A1 ratios exceeding 1.2 by either adding silica to or removing alumina from the metakaolln.(7-9) In each case, without addition of silica or deletion of alumina, only A zeolite 1s formed. 

If a clay contains many minerals, the calculation of the rational analysis can become very involved, or even impossible, according to the minerals concerned and the completeness of the chemical analysis. We shall restrict ourselves to the rational analysis of kaolin-type clays that contain the following principal impurities ... 

The principal clay-mineral of ball clays is of the kaolin type, and closely resembles kaolinite but is less well-crystallized, and its empirical formula departs slightly from the ideal, approximating to ... 

Within industry and commerce, terms other than the mineral classifications are common. Ball clay is a type of kaolin particularly suited to the manufacture of ceramics in 2004, 35% of the ball clay produced in the US was used for tile manufacture, 26% for sanitary ware, 22% for pottery and various ceramics, 11 % for other uses, and the remainder was exported. Kaolinite (which is white and soft) is of great importance in the paper industry for coatings and as a filler of the 7.8 Mt produced in the US in 2004,38% was consumed in paper manufacture within the US and 26% was exported for the same end-use. Worldwide, 44.4 Mt of kaolin-type clays were produced in 2004, the major producers being the US, Uzbekistan and the Czech Republic. 

Steadman, R., 1964. The structure of trioctahedral kaolin—type silicates. Acta Cryst. 17 924-927. 

Sodium sihcate (41°Bh, 1 3.22 ratio Na20 Si02) is added in the milling operation to disperse the slime, mosdy kaolin. Dispersion also aids the grinding process. The rod mill serves to grind the ore to 0.833 mm (—20 mesh) or to the point where mica, quart2, feldspar, and iron minerals are Hberated. Cyclones, or rake, hydrauhc, or other types of classifiers, are used after grinding to produce coarse and fine mica fractions that are treated separately. 

The 2eohtes are prepared as essentially bindedess preformed particles. The kaolin is shaped in the desired form of the finished product and is converted in situ in the pellet by treatment with suitable alkaU hydroxide solutions. Preformed pellets of 2eohte A are prepared by this method. These pellets may be converted by ion exchange to other forms such as molecular sieve Type 5A (1). ZeoHtes of higher Si02/Al202 ratios, eg, 2eohte Y, can be obtained by the same method, when sodium metasiUcate is incorporated in the preshaped pellets, or when acid-leached metakaolin is used. 

Following wet processing, fine particle size kaolins may be calcined, ie, heat treated at about 1000°C. This treatment converts the kaolin to an amorphous pigment of significantly higher brightness and opacity (8). Properties of the various types of kaolins used in paper are shown in Table 2. 

Types of Kaolin. As can be seen from Table 4, kaolins for use in polymers may be subdivided iato the categories of air-floated, water-washed, and calciaed. The processiag of each of these types is similar to that for use ia the paper iadustry. 

Kaolin (HciO washed and partially dried) 10 0.5 Imp-mill type grind to 99.9%—325 mesh... 

There are a number or types of special brick obtainable from individual producers. High-burned kaolin refractories are particularly valuable under conditions of severe temperature and heavy load or severe spalling conditions, as in the case of high-temperature oil-fired boiler settings or piers under enamehng furnaces. Another brick for the same uses is a high-fired brick of Missouri aluminous clay. 

A great variety of aluminium-silicate bearing rocks, plastic when wet, hard when dry. Used in pottery, stoneware, tile, bricks, cements, fillers and abrasives. Kaolin is one type of clay. Some clay deposits may include appreciable amounts of quartz. Commercial grades of clays may contain up to 20% quartz. 

Fig. 3 shows that NaYl contains two types of crystals Y zeolite in cubic form and Pj zeolite in spherical form with diameter of about 5 pm and 3 pm, respectively. On the other hand, NaYs contains only crystals of Y zeolite in spherical form with diameter of about 0.5 pm. It is clearly demonstrated that the diameter of zeolite synthesized fi om kaolin is much larger than that of zeolite synthesized from pine chemiceils. 

Shikazono, N. (1985e) K-Ar ages for the Yatani Pb-Zn-Au-Ag vein-type deposits and Otoge kaolin-pyrophyllite deposits, Yamagata Prefecture, northeastern part of Japan. Mining Geology, 35, 205-209 (in Japanese with English abst.). 

Kaolin A type of clay composed of mixed silicates and used for refractories, ceramics, tile and stoneware. 

The type of clays used by the rubber industry are known to the clay industry as kaolin produced from deposits of a hydrous aluminium silicate, known as kaolinite. 

The smithsonite ore type is usually composed of a mixed assemblage consisting of dolomite, Fe-oxyhydroxide, quartz clay (kaoline and montmorillonite), minor amount of... 

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. 

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