In Poland the name kaolin is referred to a white or yellowish soft clay rock mainly built of minerals of the kaolinite group. Kaolin originates in the result of a weathering or a hydrothermal decomposition of igneous and metamorphic rocks rich in feldspars. From the origin point of view, a differentiation is made between residual kaolin that is derived from an in-situ decomposition of a parent rock, and sedimentary kaolin, formed in the result of wash down of a weathered parent rock, transport and a deposition of weathering products in the other place.
The name of kaolin raw material is also referred to the Upper Cretaceous sandstones with a kaolinite cement which occur in the North Sudetic Depression. The re-analysis of Dunino deposit of basalts weathering products, originally treated as a halloysite deposit, showed that it actually represents kaolinite raw material and should be assigned to this group.
Polish deposits of kaolin raw materials originated in the result of a regional kaolinization which affected acid igneous and metamorphic rocks throughout vast areas in the foreland of the Sudety Mts., especially the Strzegom-Sobótka and Strzelin granitoid massifs as well as some parts of the Sowie Mts. and Izerskie Mts. In the Neogene times the weathering processes gave rise to the origin of thick weathering covers and, in this way, kaolin deposits. Two types of kaolin deposits are recognized here: the deposits comprising residual material and those sedimentary in nature. In both cases the deposits appear spatially related to parent rocks and confined to areas of the above mentioned massifs of granites and metamorphic rocks.
High-quality kaolin materials, that are those representing a fraction below 15 µm, are used in the manufacture of ceramics, rubber, polymers and fiberglass industries. In turn, coarser fractions find use in making recently fashionable ceramic wall and floor tiles of a „gres porcellanato” type, the production of which requires washed kaolin with a very low content of coloring oxides such as TiO2 and Fe2O3. Kaolin is also used as the raw material for the manufacture of stoneware ceramics, white cement and fire-proof products.
The demand for kaolin raw materials is largely covered by the production from domestic deposits so the share of import remains relatively small. Kaolin is being obtained also as a by-product in the exploitation of glass sands (Biała Góra depsit) and foundry sands (Grudzeń-Las deposit).
Kaolin deposits occurence is presented on the map.
Table 1 shows resources and the state of development and exploration of kaolin raw materials in Poland.
Anticipated economic resources of kaolin amounted to 211.78 million tonnes in 2017 and decreased by 299.84 thousand tonnes in comparison with the previous year due to the exploitation and losses.
Anticipated economic resources of two exploited deposits amounted to 79.11 million tonnes (37% of total anticipated economic resources).
Economic resources decreased due to the exploitation and amounted to 71.06 million tonnes in 2017 which accounts for 90% of anticipated economic resources of exploited deposits.
In 2017, the production of kaolin raw materials was bigger than in 2016 and was equal 299.83 thousand tonnes. The exploitation of Maria III deposit gave 298.60 thousand tonnes and of Dunino deposit only 1,230 tonnes of the raw material (Table 2).
The figure given below shows changes in domestic resources and production of kaolin in Poland in the years 1989-2017.
Prepared by: Agnieszka Malon