Kaolin (china clay) is a hydrated aluminum silicate crystalline mineral (kaolinite) formed over many millions of years by the hydrothermal decomposition of granite rocks. Hydrous kaolin is characterized by its fine particle size, plate like or lamellar particle shape and chemical inertness.
Clay is used in various industries like rubber, paper, ceramic, glass, paint , plastic and others. Each industry requires different grades of clay in terms of size and content of different minerals. Paper quoting is the highest value chain and possibly ceramic is more generic.
These pigments are produced through washing system, with water as process medium, to achieve grit removal and sizing, and provide attrition, filtering and drying.
Silica sand is often produced as a by-product, with uses in glass industry, foundry sand and construction activities.
Brightness of clay particle fractions is achieved by one or more processes– magnetic separation, flocculation, or flotation – for removing iron, titanium, organic, and other undesirable material.
High quality clay products are evaluated based on their particle size range and L value meaning brightness thereby. Brightness improvement requires reducing ferrous levels as well as Titanium dioxide. Fe level could be brought down from around 1.5% in the recovered clay to the desired level of <1% could be achieved. TiO2 levels however was not an issue in this clay. As regards generation of specific fractions desired by different user industries we have undertaken extensive test work by various classification technologies that the company has evolved over the years.
Each clay processing system is custom tailored based on particle size distribution and chemical composition of the feed.
| Chemical Analysis | Levigated China Clay Powder | Water Washed China Clay Powder | Natural China Clay / Kaolin Powder | Water washed China Clay Lumps | Natural China Clay / Kaolin Lumps |
| Whiteness (%) | 90% – 92% | 90% – 92% | 88% – 90% | 90% | 88% |
| Moisture (%) | < 0.5 | < 0.5 | < 0.5 | < 0.5 | < 0.5 |
| SiO2 (%) | 47 to 48 | 58 to 59 | 74 to 75 | 47 to 48 | 74 to 75 |
| Al2O3 (%) | 37 to 39 | 26 to 27 | 16 to 17 | 37 to 39 | 16 to 17 |
| K2O (%) | 3 to 3.2 | 0.5 to 1 | 0.5 to 1 | 3 to 3.2 | 0.5 to 1 |
| Na2O (%) | 0.5 to 1 | 0.5 to 1 | 1 to 2 | 0.5 to 1 | 1 to 2 |
| CaO (%) | 0.1 to 0.2 | 0.5 to 1 | 0.5 to 1 | 0.1 to 0.2 | 0.5 to 1 |
| MgO (%) | 0.2 to 0.3 | 0.4 to 0.5 | 0.3 to 0.4 | 0.2 to 0.3 | 0.3 to 0.4 |
| LOI (%) | 9 to 10 | 11 to 12 | 5 to 6 | 9 to 10 | 5 to 6 |
| Particle Size | 300 mesh | 300 mesh | 300 mesh | Lumps | Lumps |
| Top cut | 50 micron | 50 micron | 50 micron | - | - |
| Applications | Paints, Plastics,Paper Cosmetics Industry | Paints, Plastics, Paper Cosmetics Industry | Ceramic Industry, Rubber Industry and many other uses | Paints, Plastics, Paper Cosmetics Industry | Ceramic Industry, Rubber Industry and many other uses |
