PRODUCTS

KAOLIN

EC / List no.: 310-194-1
CAS no.: 1332-58-7

Kaolin (/ˈkeɪələnaɪt/ KAY-ə-lə-nyte) is a clay mineral, with the chemical composition Al2Si2O5(OH)4.
Kaolin is an important industrial mineral.
Kaolin is a layered silicate mineral, with one tetrahedral sheet of silica (SiO4) linked through oxygen atoms to one octahedral sheet of alumina (AlO6) octahedra.
Rocks that are rich in Kaolin are known as kaolin (/ˈkeɪ.ə.lɪn/) or china clay.

The name kaolin is derived from Gaoling (Chinese: 高嶺; pinyin: Gāolǐng; lit. 'High Ridge'), a Chinese village near Jingdezhen in southeastern China's Jiangxi Province.
The name entered English in 1727 from the French version of the word: kaolin, following François Xavier d'Entrecolles's reports on the making of Jingdezhen porcelain.

Kaolin has a low shrink–swell capacity and a low cation-exchange capacity (1–15 meq/100 g).
Kaolin is a soft, earthy, usually white, mineral (dioctahedral phyllosilicate clay), produced by the chemical weathering of aluminium silicate minerals like feldspar.
In many parts of the world it is colored pink-orange-red by iron oxide, giving it a distinct rust hue.
Lower concentrations yield white, yellow, or light orange colors. Alternating layers are sometimes found, as at Providence Canyon State Park in Georgia, United States.
Commercial grades of kaolin are supplied and transported as dry powder, semi-dry noodle, or liquid slurry.
This practice has also been observed within a small population of African-American women in the Southern United States, especially Georgia, likely brought by traditions of afromentioned Africans via slavery.
There, the kaolin is called white dirt, chalk, or white clay.

Kaolin is a type of clay found in nature. Kaolin is sometimes used to make medicine. Kaolin is also used as a filler in tablets.

Kaolin is used to stop bleeding and for a condition that involves swelling and sores in the mouth (oral mucositis).
Kaolin is also used for diarrhea and many other conditions, but there is no good scientific evidence to support most of these uses.

Chemistry
The chemical formula for Kaolin as used in mineralogy is Al2Si2O5(OH)4, however, in ceramics applications the formula is typically written in terms of oxides, thus the formula for Kaolin is Al2O3·2SiO2·2H2O.

Structure
Compared with other clay minerals, Kaolin is chemically and structurally simple.
Kaolin is described as a 1:1 or TO clay mineral because its crystals consist of stacked TO layers.
Each TO layer consists of a tetrahedral (T) sheet composed of silicon and oxygen ions bonded to an octahedral (O) sheet composed of oxygen, aluminum, and hydroxyl ions.
The T sheet is so called because each silicon ion is surrounded by four oxygen ions forming a tetrahedron.
The O sheet is so called because each aluminum ion is surrounded by six oxygen or hydroxyl ions arranged at the corners of an octahedron.
The two sheets in each layer are strongly bonded together via shared oxygen ions, while layers are bonded via hydrogen bonding between oxygen on the outer face of the T sheet of one layer and hydroxyl on the outer face of the O sheet of the next layer.

A Kaolin layer has no net electrical charge and so there are no large cations (such as calcium, sodium, or potassium) between layers as with most other clay minerals.
This accounts for Kaolin 's relatively low ion exchange capacity. The close hydrogen bonding between layers also hinders water molecules from infiltrating between layers, accounting for Kaolin 's nonswelling character.

When moistened, the tiny platelike crystals of Kaolin acquire a layer of water molecules that cause crystals to adhere to each other and give kaolin clay its cohesiveness.
The bonds are weak enough to allow the plates to slip past each other when the clay is being molded, but strong enough to hold the plates in place and allow the molded clay to retain its shape.
When the clay is dried, most of the water molecules are removed, and the plates hydrogen bond directly to each other, so that the dried clay is rigid but still fragile.
If the clay is moistened again, it will once more become plastic.

Structural transformations
Kaolin group clays undergo a series of phase transformations upon thermal treatment in air at atmospheric pressure.

Milling
High-energy milling of the Kaolin results in the formation of a mechanochemically amorphized phase similar to metakaolin, although, the properties of this solid are quite different.
The high-energy milling process is highly inefficient and consumes a large amount of energy.

Drying
Below 100 °C (212 °F), exposure to dry air will slowly remove liquid water from the kaolin.
The end-state for this transformation is referred to as "leather dry". Between 100 °C and about 550 °C (1,022 °F), any remaining liquid water is expelled from Kaolin .
The end state for this transformation is referred to as "bone dry".
Throughout this temperature range, the expulsion of water is reversible: if the kaolin is exposed to liquid water, it will be reabsorbed and disintegrate into its fine particulate form.
Subsequent transformations are not reversible, and represent permanent chemical changes.

Metakaolin
Endothermic dehydration of Kaolin begins at 550–600 °C producing disordered metakaolin, but continuous hydroxyl loss is observed up to 900 °C (1,650 °F).
Although historically there was much disagreement concerning the nature of the metakaolin phase, extensive research has led to a general consensus that metakaolin is not a simple mixture of amorphous silica (SiO2) and alumina (Al2O3), but rather a complex amorphous structure that retains some longer-range order (but not strictly crystalline) due to stacking of its hexagonal layers.

Needle mullite
Finally, at 1400 °C the "needle" form of mullite appears, offering substantial increases in structural strength and heat resistance.
This is a structural but not chemical transformation. See stoneware for more information on this form.

Mantles of kaolinitic saprolite are common in Western and Northern Europe. The ages of these mantles are Mesozoic to Early Cenozoic.

Kaolin clay occurs in abundance in soils that have formed from the chemical weathering of rocks in hot, moist climates—for example in tropical rainforest areas.
Comparing soils along a gradient towards progressively cooler or drier climates, the proportion of Kaolin decreases, while the proportion of other clay minerals such as illite (in cooler climates) or smectite (in drier climates) increases.
Such climatically related differences in clay mineral content are often used to infer changes in climates in the geological past, where ancient soils have been buried and preserved.

In the Institut National pour l'Étude Agronomique au Congo Belge (INEAC) classification system, soils in which the clay fraction is predominantly Kaolin are called kaolisol (from kaolin and soil).

In the US, the main kaolin deposits are found in central Georgia, on a stretch of the Atlantic Seaboard fall line between Augusta and Macon.
This area of thirteen counties is called the "white gold" belt; Sandersville is known as the "Kaolin Capital of the World" due to its abundance of kaolin.
In the late 1800s, an active kaolin surface-mining industry existed in the extreme southeast corner of Pennsylvania, near the towns of Landenberg and Kaolin, and in what is present-day White Clay Creek Preserve.
The product was brought by train to Newark, Delaware, on the Newark-Pomeroy line, along which can still be seen many open-pit clay mines.
The deposits were formed between the late Cretaceous and early Paleogene, about 100 to 45 million years ago, in sediments derived from weathered igneous and metakaolin rocks.
Kaolin production in the US during 2011 was 5.5 million tons.

During the Paleocene–Eocene Thermal Maximum sediments deposited in the Esplugafreda area of Spain were enriched with Kaolin from a detrital source due to denudation.

Synthesis and genesis
Difficulties are encountered when trying to explain Kaolin formation under atmospheric conditions by extrapolation of thermodynamic data from the more successful high-temperature syntheses.
La Iglesia and Van Oosterwijk-Gastuche (1978] thought that the conditions under which Kaolin will nucleate can be deduced from stability diagrams, based as they are on dissolution data.
Because of a lack of convincing results in their own experiments, La Iglesia and Van Oosterwijk-Gastuche (1978) had to conclude, however, that there were other, still unknown, factors involved in the low-temperature nucleation of Kaolin .
Because of the observed very slow crystallization rates of Kaolin from solution at room temperature Fripiat and Herbillon (1971) postulated the existence of high activation energies in the low-temperature nucleation of Kaolin .

At high temperatures, equilibrium thermodynamic models appear to be satisfactory for the description of Kaolin dissolution and nucleation, because the thermal energy suffices to overcome the energy barriers involved in the nucleation process. The importance of syntheses at ambient temperature and atmospheric pressure towards the understanding of the mechanism involved in the nucleation of clay minerals lies in overcoming these energy barriers.
As indicated by Caillère and Hénin (1960) the processes involved will have to be studied in well-defined experiments, because it is virtually impossible to isolate the factors involved by mere deduction from complex natural physico-chemical systems such as the soil environment.
Fripiat and Herbillon (1971), in a review on the formation of Kaolin , raised the fundamental question how a disordered material (i.e., the amorphous fraction of tropical soils) could ever be transformed into a corresponding ordered structure.
This transformation seems to take place in soils without major changes in the environment, in a relatively short period of time, and at ambient temperature (and pressure).

Low-temperature synthesis of clay minerals (with Kaolin as an example) has several aspects.
In the first place the silicic acid to be supplied to the growing crystal must be in a monomeric form, i.e., silica should be present in very dilute solution (Caillère et al., 1957; Caillère and Hénin, 1960;Wey and Siffert, 1962; Millot, 1970).
In order to prevent the formation of amorphous silica gels precipitating from supersaturated solutions without reacting with the aluminium or magnesium cations to form crystalline silicates, the silicic acid must be present in concentrations below the maximum solubility of amorphous silica.
The principle behind this prerequisite can be found in structural chemistry: "Since the polysilicate ions are not of uniform size, they cannot arrange themselves along with the metal ions into a regular crystal lattice." (Iler, 1955, p. 182)

The second aspect of the low-temperature synthesis of Kaolin is that the aluminium cations must be hexacoordinated with respect to oxygen (Caillère and Hénin, 1947; Caillère et al., 1953;Hénin and Robichet, 1955).
Gastuche et al. (1962), as well as Caillère and Hénin (1962) have concluded, that only in those instances when the aluminium hydroxide is in the form of gibbsite, Kaolin can ever be formed. If not, the precipitate formed will be a "mixed alumino-silicic gel" (as Millot, 1970, p. 343 put it).
If it were the only requirement, large amounts of Kaolin could be harvested simply by adding gibbsite powder to a silica solution.
Undoubtedly a marked degree of adsorption of the silica in solution by the gibbsite surfaces will take place, but, as stated before, mere adsorption does not create the layer lattice typical of Kaolin crystals.

The third aspect is that these two initial components must be incorporated into one and the same mixed crystal with a layer structure.

2Al(OH)3 + 2H4SiO4 -> Si2O5 . Al2(OH)4 + 5H2O

it can be seen, that five molecules of water must be removed from the reaction for every molecule of Kaolin formed.
Field evidence illustrating the importance of the removal of water from the Kaolin reaction has been supplied by Gastuche and DeKimpe (1962).
While studying soil formation on a basaltic rock in Kivu (Zaïre), they noted how the occurrence of Kaolin depended on the "degrée de drainage" of the area involved.
A clear distinction was found between areas with good drainage (i.e., areas with a marked difference between wet and dry seasons) and those areas with poor drainage (i.e., perennially swampy areas).
Only in the areas with distinct seasonal alternations between wet and dry was Kaolin found.
The possible significance of alternating wet and dry conditions on the transition of allophane into Kaolin has been stressed by Tamura and Jackson (1953).
The role of alternations between wetting and drying on the formation of Kaolin has also been noted by Moore (1964).

Laboratory syntheses
Syntheses of Kaolin at high temperatures (more than 100 °C [212 °F]) are relatively well known.
Laboratory syntheses of Kaolin at room temperature and atmospheric pressure have been described by DeKimpe et al. (1961).
From those tests the role of periodicity becomes convincingly clear.
DeKimpe et al. (1961) had used daily additions of alumina (as AlCl3·6 H2O) and silica (in the form of ethyl silicate) during at least two months.
In addition, adjustments of the pH took place every day by way of adding either hydrochloric acid or sodium hydroxide. Such daily additions of Si and Al to the solution in combination with the daily titrations with hydrochloric acid or sodium hydroxide during at least 60 days will have introduced the necessary element of periodicity.
Only now the actual role of what has been described as the "aging" (Alterung) of amorphous alumino-silicates (as for example Harder, 1978 had noted) can be fully understood.
Time as such is not bringing about any change in a closed system at equilibrium; but a series of alternations, of periodically changing conditions (by definition, taking place in an open system), will bring about the low-temperature formation of more and more of the stable phase Kaolin instead of (ill-defined) amorphous alumino-silicates.

Uses:
The main use of the mineral Kaolin (about 50% of the time) is the production of paper; its use ensures the gloss on some grades of coated paper.

Kaolin is also known for its capabilities to induce and accelerate blood clotting.
In April 2008 the US Naval Medical Research Institute announced the successful use of a Kaolin -derived aluminosilicate infusion in traditional gauze, known commercially as QuikClot Combat Gauze, which is still the hemostat of choice for all branches of the US military.

Kaolin is used (or was used in the past):
• Kaolin is used in ceramics (it is the main component of porcelain).
• Kaolin is used in toothpaste
• Kaolin is used as a light-diffusing material in white incandescent
• Kaolin is used in light bulbs
• Kaolin is used in cosmetics
• Kaolin is used in industrial insulation material called Kaowool (a form of mineral wool).
• Kaolin is used in 'pre-work' skin protection and barrier creams
• Kaolin is used in paint to extend the titanium dioxide (TiO2) white pigment and modify gloss levels.
• Kaolin is used for modifying the properties of rubber upon vulcanization.
• Kaolin is used in adhesives to modify the rheology
• Kaolin is used in organic farming as a spray applied to crops to deter insect damage, and in the case of apples, to prevent sunscald
as whitewash in traditional stonemasonry homes in Nepal (the most common method is to paint the upper part with white kaolin clay and the middle with red clay; the red clay may extend to the bottom, or the bottom may be painted black).
• Kaolin is used as a filler in Edison Diamond Discs.
• Kaolin is used as a filler to give bulk, or a coating to improve the surface in papermaking.
• Kaolin is used as an indicator in radiological dating since Kaolin can contain very small traces of uranium and thorium.
• Kaolin is used to soothe an upset stomach, similar to the way parrots (and later, humans) in South America originally used it (more recently, industrially-produced Kaolin preparations were common for the treatment of diarrhea; the most common of these was Kaopectate, which abandoned the use of kaolin in favor of attapulgite and then (in the United States) bismuth subsalicylate.
• Kaolin is used for facial masks or soap (known as "White Clay").
• Kaolin is used for spa body treatments, such as body wraps, cocoons, or spot treatments such as just the feet, back, or hands.
• Kaolin is used in the essential oil can be added to add a pleasant aroma, or seaweed can be added to boost the nutrient values of the treatment.
• Kaolin is used as adsorbents in water and wastewater treatment
to induce blood clotting in diagnostic procedures, e.g. Kaolin clotting time.
• Kaolin is used in its altered metakaolin form, as a pozzolan; when added to a concrete mix, metakaolin accelerates the hydration of Portland cement and takes part in the pozzolanic reaction with the portlandite formed in the hydration of the main cement minerals (e.g. alite).
• Kaolin is used in its altered metakaolin form, as a base component for geopolymer compounds
• Kaolin is used in Geophagy
• Kaolin is used Humans sometimes eat kaolin for pleasure or to suppress hunger, a practice known as geophagy.
• Kaolin is used In Africa, kaolin used for such purposes is known as kalaba (in Gabon and Cameroon), calaba, and calabachop (in Equatorial Guinea).
• Kaolin is used Consumption is greater among women, especially during pregnancy, and its use is sometimes said by women of the region to be a habit analogous to cigarette smoking among men.

This practice has also been observed within a small population of African-American women in the Southern United States, especially Georgia, likely brought by traditions of afromentioned Africans via slavery.
There, the kaolin is called white dirt, chalk, or white clay.

Safety
Kaolin is generally recognized as safe, but may cause mild irritation of the skin or mucous membranes.
Kaolin products may also contain traces of crystalline silica, a known carcinogen.

People can be exposed to kaolin in the workplace by breathing in the powder or from skin or eye contact.

United States
The Occupational Safety and Health Administration (OSHA) has set the legal limit (permissible exposure limit) for kaolin exposure in the workplace as 15 mg/m3 total exposure and 5 mg/m3 respiratory exposure over an 8-hour workday.
The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 10 mg/m3 total exposure TWA 5 mg/m3 respiratory exposure over an 8-hour workday.

Geotechnical engineering
Research results show that the utilization of Kaolin in geotechnical engineering can be alternatively replaced by safer illite, especially if its presence is less than 10.8% of the total rock mass.

kaolinite, group of common clay minerals that are hydrous aluminum silicates; they comprise the principal ingredients of kaolin (china clay).
The group includes Kaolin and its rarer forms, dickite and nacrite, halloysite, and allophane, which are chemically similar to Kaolin but amorphous.

Kaolinite, nacrite, and dickite occur as minute, sometimes elongated, hexagonal plates in compact or granular masses and in micalike piles.
They are natural alteration products of feldspars, feldspathoids, and other silicates.
Anauxite, which was previously regarded as a kaolinite-group mineral possessing a higher than usual silica-alumina ratio, is now considered to be Kaolin and free silica (mainly noncrystalline).

Kaolin is a clay mineral, with a soft consistency and earthy texture.
Kaolin is easily broken and can be molded or shaped, especially when wet.
Kaolin is a lackluster and uninteresting mineral on its own, but it occasionally forms interesting pseudomorphs, especially after feldspars.
Kaolin is also a common accessory to other minerals, including gem crystals in decomposing feldspar pegmatites.

The term Kaolin describes the name of a group of closely-related clay minerals, as well as an individual member mineral of the group.
The members of the Kaolin group all have the same (or similar) chemical formula, and they are Dickite, Kaolinite, Nacrite, Halloysite, and Odinite.
Kaolin also has a very similar chemical formula to Serpentine, and is sometimes considered a member of the Serpentine group.

Kaolin is the most common clay mineral, and entire clay deposits can be composed of this mineral.
There are many commercial Kaolin mines where this mineral is mined in large volumes for its various industrial uses.
Kaolin is named after the Kao-ling, a mountain in Jiangxi Province in China where this mineral was well-known from early times.

Chemical Formula:Al2Si2O5(OH)4
Composition:Basic aluminum silicate
Color:White, gray, yellow, beige.
May also be darker colored brown, orange, or reddish-brown from iron oxide impurities.
Streak:White
Hardness 2 - 2.5
Crystal System:Monoclinic
Crystal Formsand Aggregates:Most often as unshaped compact masses.
Crystals are microcrytalline as tiny grains and plates.
Crystals are rarely visible to the naked eye.
Transparency:Opaque. Rarely translucent.
Specific Gravity:2.6
Luster:Dull
Cleavage:1,1
Fracture:Earthy
Tenacity:Brittle, sectile
Other ID Marks.Kaolin is very friable, and can be cut and molded, especially when wet.
May also give off a clay-like odor when wet or when breathed upon.
In Group Silicates; Phyllosilicates
Striking Features:Friable habit and clay-like texture

Uses:
Kaolin is the most abundant clay mineral, and is used for pottery and ceramics.
Kaolin is also very important in the production of paper, and is used in pharmaceuticals as an ingredient in some medications such as stomach soothers.
Kaolin is also used as an ingredient in some cosmetics, soaps, paint gloss, and toothpastes.

Kaolin is a clay mineral with chemical composition Al2Si2O5(OH)4.
Kaolin is an important industrial mineral.
Rocks rich in Kaolin are called kaolin.
Kaolinite, common group of clay minerals that are hydrated aluminum silicates; they contain the main components of kaolin (china clay).
The group includes kaolinite, which is chemically similar but amorphous to kaolinite, and its rarer forms, stalagmite and nacrite, halloysite and allophane.

Kaolin is a layered silicate mineral with a tetrahedral silica layer (SiO4) bonded to an octahedral layer of alumina (AlO6) octahedra through oxygen atoms.

Kaolinite, nacrite, and dickite occur as compact or granular masses and mica-like clumps as small, sometimes elongated, hexagonal plates.
Feldspars are natural change products of feldspathoids and other silicates.
Anoxide, previously considered a Kaolin group mineral with a higher-than-normal silica-to-alumina ratio, is now considered Kaolin and free silica (mainly non-crystalline).
For chemical formula and detailed physical properties

Kaolin is the raw material of brick, pottery and tile.
Kaolin has played a vital role in the development of human civilization.
The most important of these minerals is kaolinite.
Kaolin Kaolin forms white, microscopic, pseudo-hexagonal plates.

compact or granular masses and mica-like clumps.
Three other minerals – stalagmite, nacrite and halloysite – chemically identical to kaolinite, but monoclinic system.
Four found together and often visually indistinguishable.

Kaolin is a natural product of mica degradation.
plagioclase and sodium-potassium feldspars under Effect of water, dissolved carbon dioxide and organic matter acids.
Used in agriculture, as a filler in foods such as chocolate, mixed with pectin as an antidiarrheal, as paint expander, as a reinforcing agent in rubber, and as powder agent in foundry operations

Overview
Kaolin is a significant industrial clay that mainly contains a hydrated aluminum silicate mineral named as Kaolin (Al2Si2O5(OH)4).
Other kaolin minerals include dickite, nacrite, and halloysite. Pure forms of these minerals are not as ubiquitous as kaolinite, and are usually found along with Kaolin in hydrothermal deposits.
Kaolin may form in residual or sedimentary modes.
In the former type, Kaolin is created by in-situ weathering or hydrothermal alteration of aluminosilicate parent rocks like granite; though, in the latter, the mineral is produced by the deposition of Kaolin formed elsewhere.
Unique mineralogy, morphology, chemical and physical specifications of kaolin make it a versatile raw material appropriate for many different applications , such as ceramic, paper coating and fillers, pigment extender in water-based interior latex paints and oil-based exterior industrial primer.
In addition, kaolin is applied in non-black rubber, medicines and pharmaceuticals, cosmetics, crayons, fertilizers, detergents, pesticides, white cement, ink, catalysts, and many other products.
These properties are greatly affected by the mode of clay formation which controls the kaolin quality through varying the Kaolin and impurity contents.
For instance, Kaolin content of the residual and sedimentary kaolins differs from 20% to 60%, respectively.
High quality kaolins are also low in iron-bearing minerals.
The existence of iron oxides in kaolin adversely affects the clay color, and reduces its brightness and refractoriness .
These cause a dramatic decrease in its commercial price.
Even an amount of 0.4% of oxides, hydroxides and hydrated oxides of ferric iron may be enough to impart a red to yellow pigmentation to clay deposits.
These iron oxide/hydroxides may be hematite (red), maghemite (reddish brown), goethite (brownish yellow), lepidocrocite (orange), ferrihydrate (brownish red), etc.
Similarly, iron ores such as hematite may contain clays like kaolin as contamination which cause problems in the operation of blast furnaces.
Therefore, the first beneficiation step to make these raw materials commercially valuable is to effectively eliminate iron oxides from Kaolin clays and vice versa.

Structure and physical properties
Kaolin is a plastic raw material, particularly consisting of the clay mineral kaolinite.
The chemical formula is Al2O3.2SiO2.2H2O (39.5% Al2O3, 46.5% SiO2, 14.0% H2O). In systemic mineralogy, Kaolin ranks among phyllosilicates, which are stratified clay minerals formed by a net of tetrahedral and octahedral layers.
Phyllosilicates are classified into the main groups according to the type of the layers, interlayer content, charge of the layers and chemical formulas.
Besides Kaolin groups, serpentine, halloysite, pyrofylite, mica, and montmorillonite groups also rank among phyllosilicates.
Group of kaolinites includes di-octahedral minerals (1:1) with two layers, one silica[SiO4] tetrahedral layer and one aluminium[Al2(OH)4] octahedral layer.
The layers are bonded together by sharing oxygen anion between Al and Si. Together, these two layers are called platelets.
The 1:1 platelets of Kaolin are held together strongly via hydrogen bonding between the OH of the octahedral layer and the O of the tetrahedral layer.
Due to this strong attraction, these platelets do not expand when hydrated and Kaolin only has external surface area.
Also, Kaolin has very little isomorphic substitution of Al for Si in the tetrahedral layer. Accordingly, it has a low cation exchange capacity. Kaolin easily adsorbs water and forms a plastic, paste-like substance.

Availability, mining and processing
Kaolin is formed under acidic conditions through weathering or hydrothermal changes of feldspars, and – to a lower extent – also other aluminosilicates.
Kaolin can form independent weathered kaolin deposits, Kaolin clays or may be a compound of Kaolin sandstones and oolitic ironstones, and less frequently also of pegmatites and hydrothermal deposits.
The most significant kaolin deposits were formed through intensive weathering of rocks rich in feldspar (granite, arkose, certain types of ortho-gneisses, and migmatites).
Millions of years ago, original material was decomposed by weathering, giving rise to kaolin and silica combined with higher or lower amounts of admixtures.
Mechanical erosion formed the rock under the tropical climate of that era and at increased temperatures, chemical corrosion occurred under the activity of water saturated with CO2 and humic acids which eluted from water.
World renowned deposits in the Czech Republic are especially situated in the district of Karlovy Vary (Sedlec, Podlesi, and Otovice).
Kaolin deposits in the area of Karlovy Vary are primary, i.e. kaolin remained in the place of its formation.
Extracted raw material contains 20 to 30% kaolin; the remainder is silica sand which is an integral part of the raw material.
Deeper deposits tend to be less kaolinized. Larger areas with kaolin material contents of 15 to 35% formed through weathering of arkoses are found in the vicinity of Horni Briza, Kaznejov, and Chotikov.
Lower quality kaolin deposites are near Nova Role, Vidnava, Kadan, Podborany, Znojmo, and Veverska Bityska.
Kaolin was obtained from extracted Kaolin or kaolinite-illitic gritstone or pudding-stone from the "mine U" in southern Moravia using the following procedure (unpublished data):
Superficial soil layer (about 50 cm) was removed, and the raw material was floated to a suction pump by water cannon (water source was a pond formed on the surface of the mine after kaolin extraction).
Kaolin was transported in the form of dense slurry through about 150 m long pipeline with about 20 cm in diameter to the processing plant halls.
After kaolin washing, classification and separation steps according to the particle size, kaolin sedimentation, addition of colloid agent, and kaolin drying in wire baskets, the product was finished and could be dispatched to customers.

Chemical Properties
off-white powder
Kaolin occurs as a white to grayish-white colored, unctuous powder free from gritty particles.
Kaolin has a characteristic earthy or claylike taste, and when moistened with water it becomes darker in color and develops a claylike odor.
Occurrence:
Kaolin is a naturally occurring clay that is treated for impurities.

kaolin (China clay) is a mixture of various aluminum silicates. Kaolin is often used in powders and masks given its absorbent, abrasive, bulking, and opacifying properties.
This white, soft powder has good coverage and absorption abilities for both water and oil, making it an appropriate absorber of the oil and sweat secreted by the skin.
Kaolin adheres well to the skin’s surface, yet is easily removed with normal cleansing procedures. Kaolin is considered a non-comedogenic raw material.
Adsorbant.
Definition A mixture of clays, quartz, and feldspar usually containing at least 25% alumina.
Ball and china clays are ordinarily used. A slip or slurry is formed with water to form a plastic, moldable mass, which is then glazed and fired to a hard, smooth solid.

Production Methods
Kaolin is a hydrated aluminum silicate obtained by mining naturally occurring mineral deposits.
Large deposits are found in Georgia, USA and in Cornwall, England.
Mined kaolin is powdered and freed of coarse, gritty particles either by elutriation or by screening.
Impurities such as ferric oxide, calcium carbonate, and magnesium carbonate are removed with an electromagnet and by treatment with hydrochloric acid and/or sulfuric acids.
Definition clay: A fine-grained deposit consistingchiefly of clay minerals. Kaolin ischaracteristically plastic and virtuallyimpermeable when wet and crackswhen it dries out.
In geology the sizeof the constituent particles is usuallytaken to be less than 1/256 mm.
In soil science clay is regarded as a soilwith particles less than 0.002 mm insize.

Indications
Kaolin is a naturally occurring hydrated aluminum silicate that is prepared for medicinal use as a very finely divided powder.
The rationale behind its use in acute nonspecific diarrhea stems from its ability to adsorb some of the bacterial toxins that often cause the condition.

Overview Kaolin is a significant industrial clay that mainly contains a hydrated aluminum silicate mineral named as Kaolin (Al2Si2O5(OH)4).
Other kaolinminerals include dickite, nacrite, and halloysite. Pure forms of these minerals are not as ubiquitous as kaolinite, and are usually found along with Kaolin in hydrothermal deposits.
Kaolin may form in residual or sedimentary modes.
In the former type, Kaolin is created by in-situ weathering or hydrothermal alteration of aluminosilicate parent rocks like granite; though, in the latter, the mineral is produced by the deposition of Kaolin formed elsewhere.
Unique mineralogy, morphology, chemical and physical specifications of kaolin make it a versatile raw material appropriate for many different applications, such as ceramic, paper coating and fillers, pigment extender in water-based interior latex paints and oil-based exterior industrial primer.
In addition, kaolin is applied in non-black rubber, medicines and pharmaceuticals, cosmetics, crayons, fertilizers, detergents, pesticides, white cement, ink, catalysts, and many other products.
These properties are greatly affected by the mode of clay formation which controls the kaolin quality through varying the Kaolin and impurity contents.
For instance, Kaolin content of the residual and sedimentary kaolins differs from 20% to 60%, respectively.
High quality kaolins are also low in iron-bearing minerals.
The existence of iron oxides in kaolin adversely affects the clay color, and reduces its brightness and refractoriness.
These cause a dramatic decrease in its commercial price. Even an amount of 0.4% of oxides, hydroxides and hydrated oxides of ferric iron may be enough to impart a red to yellow pigmentation to clay deposits.
These iron oxide/hydroxides may be hematite (red), maghemite (reddish brown), goethite (brownish yellow), lepidocrocite (orange), ferrihydrate (brownish red), etc.
Similarly, iron ores such as hematite may contain clays like kaolin as contamination which cause problems in the operation of blast furnaces.
Therefore, the first beneficiation step to make these raw materials commercially valuable is to effectively eliminate iron oxides from Kaolin clays and vice versa.

Structure and physical properties
Kaolin is a plastic raw material, particularly consisting of the clay mineral kaolinite.
The chemical formula is Al2O3.2SiO2.2H2O (39.5% Al2O3, 46.5% SiO2, 14.0% H2O).
In systemic mineralogy, Kaolin ranks among phyllosilicates, which are stratified clay minerals formed by a net of tetrahedral and octahedral layers.
Phyllosilicates are classified into the main groups according to the type of the layers, interlayer content, charge of the layers and chemical formulas.
Besides Kaolin groups, serpentine, halloysite, pyrofylite, mica, and montmorillonite groups also rank among phyllosilicates.
Group of kaolinites includes di-octahedral minerals (1:1) with two layers, one silica[SiO4] tetrahedral layer and one aluminium[Al2(OH)4] octahedral layer.
The layers are bonded together by sharing oxygen anion between Al and Si. Together, these two layers are called platelets.
The 1:1 platelets of Kaolin are held together strongly via hydrogen bonding between the OH of the octahedral layer and the O of the tetrahedral layer.
Due to this strong attraction, these platelets do not expand when hydrated and Kaolin only has external surface area.
Also, Kaolin has very little isomorphic substitution of Al for Si in the tetrahedral layer. Accordingly, it has a low cation exchange capacity.

Kaolin easily adsorbs water and forms a plastic, paste-like substance.
Availability, mining and processing
Kaolin is formed under acidic conditions through weathering or hydrothermal changes of feldspars, and – to a lower extent – also other aluminosilicates.
Kaolin can form independent weathered kaolin deposits, Kaolin clays or may be a compound of Kaolin sandstones and oolitic ironstones, and less frequently also of pegmatites and hydrothermal deposits.
The most significant kaolin deposits were formed through intensive weathering of rocks rich in feldspar (granite, arkose, certain types of ortho-gneisses, and migmatites).
Millions of years ago, original material was decomposed by weathering, giving rise to kaolin and silica combined with higher or lower amounts of admixtures.
Mechanical erosion formed the rock under the tropical climate of that era and at increased temperatures, chemical corrosion occurred under the activity of water saturated with CO2 and humic acids which eluted from water.
World renowned deposits in the Czech Republic are especially situated in the district of Karlovy Vary (Sedlec, Podlesi, and Otovice).
Kaolin deposits in the area of Karlovy Vary are primary, i.e. kaolin remained in the place of its formation.
Extracted raw material contains 20 to 30% kaolin; the remainder is silica sand which is an integral part of the raw material.
Deeper deposits tend to be less kaolinized.
Larger areas with kaolin material contents of 15 to 35% formed through weathering of arkoses are found in the vicinity of Horni Briza, Kaznejov, and Chotikov.
Lower quality kaolin deposites are near Nova Role, Vidnava, Kadan, Podborany, Znojmo, and Veverska Bityska.
Kaolin was obtained from extracted Kaolin or kaolinite-illitic gritstone or pudding-stone from the "mine U" in southern Moravia using the following procedure (unpublished data):
Superficial soil layer (about 50 cm) was removed, and the raw material was floated to a suction pump by water cannon (water source was a pond formed on the surface of the mine after kaolin extraction).
Kaolin was transported in the form of dense slurry through about 150 m long pipeline with about 20 cm in diameter to the processing plant halls.
After kaolin washing, classification and separation steps according to the particle size, kaolin sedimentation, addition of colloid agent, and kaolin drying in wire baskets, the product was finished and could be dispatched to customers.

Chemical Properties
off-white powder
Kaolin occurs as a white to grayish-white colored, unctuous powder free from gritty particles. Kaolin has a characteristic earthy or claylike taste, and when moistened with water it becomes darker in color and develops a claylike odor.
Occurrence
Kaolin is a naturally occurring clay that is treated for impurities.

Uses:
Kaolin has been used:
For preparing synthetic turbid water that is employed to evaluate the biosorption capacity of Moringa oleifera leaves.
In combination with carrageenan to induce arthritic inflammation in a rat model for evaluating the activity of JAK3 (janus kinase 3) inhibitors.
In a study to assess its utility for microparticle-enhanced cultivation (MPEC) of 2-phenylethanol and 6-pentyl-α-pyrone.
kaolin (China clay) is a mixture of various aluminum silicates. Kaolin is often used in powders and masks given its absorbent, abrasive, bulking, and opacifying properties.
This white, soft powder has good coverage and absorption abilities for both water and oil, making it an appropriate absorber of the oil and sweat secreted by the skin.
Kaolin adheres well to the skin’s surface, yet is easily removed with normal cleansing procedures. Kaolin is considered a non-comedogenic raw material.
Adsorbant.
Definition
A mixture of clays, quartz, and feldspar usually containing at least 25% alumina. Ball and china clays are ordinarily used.
A slip or slurry is formed with water to form a plastic, moldable mass, which is then glazed and fired to a hard, smooth solid.

Definition
clay: A fine-grained deposit consistingchiefly of clay minerals.
Kaolin ischaracteristically plastic and virtuallyimpermeable when wet and crackswhen it dries out.
In geology the sizeof the constituent particles is usuallytaken to be less than 1/256 mm.
Insoil science clay is regarded as a soilwith particles less than 0.002 mm insize.

General Description
Odorless white to yellowish or grayish powder.
Contains mainly the clay mineral Kaolin (Al2O3 SiO2)2 H2O)2), a hydrous aluminosilicate. Kaolin has mp 740-1785°C and density: 2.65 g cm-3.
KAOLINe is insoluble in water but darkens and develops a earthy odor when wet.

Pharmaceutical Applications
Kaolin is a naturally occurring mineral used in oral and topical pharmaceutical formulations.
In oral medicines, kaolin has been used as a diluent in tablet and capsule formulations; it has also been used as a suspending vehicle.
In topical preparations, sterilized kaolin has been used in poultices and as a dusting powder.
Therapeutically, kaolin has been used in oral antidiarrheal preparations.

Industrial uses
The name kaolin comes from the two Chinese words kao-ling, meaning high ridge, and was originally a local term used to describe the region from which the clay was obtained.
Kaolin (Al2O32SiO22 H2O) usually contains less than 2% alkalies and smaller quantities of iron, lime, magnesia, and titanium. Because of its purity, kaolin has a high fusion point and is the most refractory of all clays.
Lone kaolins are widely used in casting sanitaryware, ceramics, and refractories.
Georgia china clay is one of the most uniform kaolins to be found.
Generally speaking, there are two types of Georgia-sourced kaolin, both of which are widely used for casting and other processes.
One type imparts unusually high strength and plasticity, and is used for both casting and jiggering where a high degree of workability is required.
The other type typically is a fractionated, controlled particle size clay that also behaves well in casting, dries uniformly, and reduces cracking of ware.

Kaolin appears as odorless white to yellowish or grayish powder. Contains mainly the clay mineral Kaolin (Al2O3(SiO2)2(H2O)2), a hydrous aluminosilicate.
Kaolin has mp 740-1785°C and density 2.65 g/cm3.
Kaolin is insoluble in water but darkens and develops a earthy odor when wet.

Kaolin is an aluminosilicate soft white mineral named after the hill in China (Kao-ling) from which it was mined for centuries.
In its natural state kaolin is a white, soft powder consisting principally of the mineral kaolinite, and varying amounts of other minerals such as muscovite, quartz, feldspar, and anatase.
Kaolin is used in the manufacture of china and porcelain and also widely used in the production of paper, rubber, paint, drying agents, and many other products.
Kaolin has a role as an excipient and an antidiarrhoeal drug.
Kaolin is a mixture and an aluminosilicate mineral.
Kaolin contains a kaolinite.

Industry Uses
• Abrasives
• Adhesives and sealant chemicals
• Catalyst
• Fillers
• Ion exchange agents
• Laboratory chemicals
• Main component of ceramics bodies.
• Major component in ceramics manufacturing.
• Major component of ceramics.
• Oxidizing/reducing agents
• Paint additives and coating additives not described by other categories
• Pigments
• Plasticizers
• Process regulators
• Processing aids, not otherwise listed
• Refractories
• Refractory Materials
• Surface active agents
• Viscosity adjustors
• auto parts manufacturing
• formulation ingredient in pelleted enzyme products. Typically this type of product is used in further formulations for auto-dishwash or powder detergents.
• used as ingredient in brake pad.

Consumer Uses
• Adhesives and sealants
• Apparel and footwear care products
• Arts, crafts, and hobby materials
• Automotive care products
• Automotive interior products
• Building/construction materials - wood and engineered wood products
• Building/construction materials not covered elsewhere
• Catalyst
• Cleaning and furnishing care products
• Fabric, textile, and leather products not covered elsewhere
• Fire Suppression Chemical
• Fire suppression chemical
• Floor coverings
• Fuels and related products
• Furniture and furnishings not covered elsewhere
• High temperature refractories for furnace linings.
• Metal Catalyst
• Non-TSCA use
• Paints and coatings
• Paper products
• Personal care products
• Plastic and rubber products not covered elsewhere
• Rubber Tires
• Toiletries/cosmetics

Household & Commercial/Institutional Products
• Auto Products
• Commercial / Institutional
• Hobby/Craft
• Home Maintenance
• Inside the Home
• Landscaping/Yard
• Personal Care
• Pesticides
• Pet Care

General Manufacturing Information
Industry Processing Sectors
• Adhesive manufacturing
• All other basic inorganic chemical manufacturing
• Asphalt paving, roofing, and coating materials manufacturing
• Construction
• Cosmetics - Inert
• Furniture and related product manufacturing
• Laboratory Use
• Miscellaneous manufacturing
• Nonmetallic mineral product manufacturing (includes clay, glass, cement, concrete, lime, gypsum, and other nonmetallic mineral product manufacturing.
• Paint and coating manufacturing
• Paper manufacturing
• Petroleum refineries
• Pharmaceutical and medicine manufacturing
• Plastic material and resin manufacturing
• Rubber product manufacturing
• Services
• Soap, cleaning compound, and toilet preparation manufacturing
• Synthetic rubber manufacturing
• Textiles, apparel, and leather manufacturing
• Transportation equipment manufacturing
• Utilities
• formulation ingredient for enzyme product. Sold to downstream users who use in any number of applications--most likely auto-dish wash or powder laundry detergents

IUPAC NAMES:
Aluminium Silicate
Aluminium silicate
aluminium silicate
Aluminium Silicate Hydroxide
Aluminium silicate hydroxide
aluminum oxosilanediolate (2:3)
Aluminum silicate
aluminum silicate dihydrate
Aluminum silicate hydroxide
Aluminum Silicate Hydroxide (Kaolin)
Aluminumsilicat (hydratisiert)
caolin
dioxosilane
hydrated aluminium silicate
Hydrated aluminum silicate
hydrous aluminum silicate
KAOLIN
Kaolin
kaolin
Kaolin (aluminum silicate hydroxide)
KAOLIN (BOUND)
Kaolin Clay
kaolinit
KOALIN
Naturally occurring substances, kaolin (CI 77004)
oxo-oxoalumanyloxy-[oxo(oxoalumanyloxy)silyl]oxysilane;dihydrate

SYNONYMS:
Anhydrol
Argilla
Bilt-cote
Bilt-plates
Buca
Catalpo
Chinaclaypowder
PAR CLAY
PIPE CLAY
HYDRATED ALUMINUM SILICATE
DIXIE CLAY
CHINA CLAY
CLAY CHINA
CLAY
CLAY ACTIVATED
BILT-PLATES 156
BOLE WHITE POWDER
BOLUS
BOLUS ALBA
LANGFORD
LANGFORD CLAY
KAOLIN, LIGHT
KAOLINUM
KAOLIN
KAOLIN, CALCINED DIHYDRATE
MCNAMEE CLAY
ALUMINUM SILICATE DIHYDRATE
ALUMINUM SILICATE (HYDRATED)
ALUMINUM SILICATE HYDROXIDE
ALUMINIUM SILICATE DIHYDRATE
ALUMINIUM SILICATE (HYDRATED)
kaolin uncalcined
Kaoline
KaolinAluminium silicate (hydrated)
Kaolite
Kaolin, Powder, USP
Kaolin 1KG
Kaolin(superfine)
KAOLIN POWDER 2,5 KG
Colloidal Kaolin - BC 2747
Kaolin anhydrous, free-flowing, Redi-Dri(TM)
BOLE WASHED (KAOLIN)
Kaolin,anhydrous, free-flowing
Imerys Glomax LL kaolin
Imerys polwhite E kaolin
Imerys polwhite ED kaolin
Clays,China
Clays,white
Continental clay
Fiberfrax 6000 RPS
Fiberkal
Huber 40C
Huber 65A
Huber 95
Kaolin clay
kaolinite(al2(si2o7).2h2o)
Kaopectate
Kaowool