The use of natural mineral pigments to produce paints has been known for millennia. Although synthetic inorganic pigments currently dominate our daily lives, the demand for chemically and thermally stable geogenic mineral pigments is growing. Since they are other than synthetic chemical compounds free from allergy-causing and toxic substances, their use in the cosmetic industry is increasing. The discovery of relatively large deposits of mineral pigments as a by-product of brown coal mining in the North Bohemian basin with very good quality of mineral raw materials sparked a special interest in this natural resource.
From the earth colours chemically and thermally stable and fade resistant brown, red, yellow, green and white pigments can be produced. The AKW Apparate + Verfahren GmbH (Hirschau) and the Technical University of Ostrava in the Czech Republic developed a new wet-mechanical treatment method for complete separation of the mineral phases. The geological and mineralogical studies confirmed mineable deposits of bolus and ocher-coloured earth in the investigated area. Technical preparation studies have shown that from the investigated crude gestures usable pigments can be produced in consistent quality. The obtained pigments proved in an approved, independent laboratory test their quality according to the relevant EN standards for colour pigments.
It was demonstrated that the prepared pigments are suitable for a range of products – like paints, colouring building materials and colouring of plastics.
