Description: kaolin, also called china clay, soft white clay that is an essential ingredient in the manufacturing. In its natural state kaolin is a white, soft powder consisting principally of the mineral kaolinite. Kaolinite is a clay mineral, part of the group of industrial minerals, with the chemical composition Al2Si2O5(OH)4. It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedral. Rocks that are rich in kaolinite are known as kaolin or china clay.
Occurrence: Kaolinite 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 kaolinite 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.
Locations: An estimated reserve of 3 billion tonnes of good kaolinific clays has been identified. It has been discovered in almost all the states in Nigeria like Uzubulu in Anambra, Enugu in Enugu state, Major Porter in Plateau, Darazo in Bauchi, Jalgawa in Bauchi, Barmojo and Onibode in Ogun state, Kwali in FCT, Kotanara in FCT, Other states where
available are Katsina, Kebbi, Oyo, Ondo, Ekiti, Kogi, Niger and Kaduna States
Specifications: Kaolin specifications consist of physical and chemical aspects. The two area of specifications are shown in the Table below.
Physical Specification
| Specifications | Value |
| Whiteness (%) | ≥93.5 |
| Particle size (-2μm,%) | 80-84 |
| Residue on 325mesh (%) | ≤0.003 |
| Oil absorption (g/100g) | 55-65 |
| PH | 6.0-8.0 |
| Water content (%) | ≤1.0 |
| Average particle size(μm) | ≤0.9 |
| Refractivity | 1.62 |
| Dispersion (μm) | ≤45 |
Chemical specification
| SiO2% | Al2O3% | Fe2O3% | TiO2% | CaO% | MgO% | K2O% | NaO% | MnO% |
| 52±2 | 45±2 | ≤0.5 | ≤0.8 | 0.5 | 0.3 | 0.1 | 0.2 | 0.004 |
Uses: Approximately 40 percent of the kaolin produced is used in the filling and coating of paper. In filling, the kaolin is mixed with the cellulose fibre and forms an integral part of the paper sheet to give it body, colour, opacity, and printability. In coating, the kaolin is plated along with an adhesive on the paper’s surface to give gloss, colour, high opacity, and greater printability. Kaolin used for coating is prepared so that most of the kaolinite particles are less than two micrometers in diameter. Kaolin is used extensively in the ceramic industry, where its high fusion temperature and white burning characteristics makes it particularly suitable for the manufacture of whiteware (china), porcelain, and refractories. Substantial tonnages of kaolin are used for filling rubber to improve its mechanical strength and resistance to abrasion. For this purpose, the clay used must be extremely pure kaolinite and exceedingly fine grained. Kaolin is also used as an extender and flattening agent in paints. It is frequently used in adhesives for paper to control the penetration into the paper. Kaolin is an important ingredient in ink, organic plastics, some cosmetics, and many other products where its very fine particle size, whiteness, chemical inertness, and absorption properties give it particular value.
Export market: The major export markets Iron ore is China. Other buyers next to china include India, Bangladesh, USA, South Africa, Japan and Hong Kong.
Export Price: Depending on the purity and other components of the Kaolin the FOB price could be as low as USD100-150/MT and it could be as high as USD200-300/MT or more.
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