Building ceramics raw materials
Mineral raw materials used in the industry of building ceramics are varying in age and origin. Raw materials currently exploited for the needs of that industry in Poland come from deposits ranging in age from the Permian to Quaternary. The deposits are distributed practically throughout the whole country. However, they are more common and larger in the south also their differentiation appears higher than in other parts of the country.
The main building ceramic products are: ceramic bricks and breezeblocks, slates, clinker bricks, ceramic pavements.
Main raw materials used for building ceramics production are clay rocks. Their suitability depends on their plasticity after they are mixed with water. If the plasticity is too high, the mix is corrected by adding such ingredients as sand, crushed brick and fly ash and sawdust. Clay and non-clay raw materials very often occur together - in one deposit.
Raw materials for building ceramics production contain clayey minerals. In loess clayey minerals content is low (couple of %), but in clays it can be 100 %. Usually the content is between 40-60 %. Other components are quartz sand and dust, feldspars, calcite and dolomite, iron minerals, mica minerals and organic matter.
The most important raw materials of the Quaternary age include stagnant lake sediments such as muds and clays occurring mainly in northern and central Poland as well as loess, glacial tills, alluvial sediments and those of weathering covers and sands. The most important raw materials of the Tertiary age include clays of the so-called Poznań Series from south-western and central Poland and those of the Krakowiec Clays from the area of the Carpathian Foredeep in south-eastern Poland. The Triassic and Jurassic deposits are situated at the margin of the Holy Cross Mts and in the Czestochowa and Opole regions. Building ceramics raw materials deposits in Poland are presented on the map.
According to the Regulation of the Minister of the Environment of the 22nd of December 2011 (number of Polish act: Dz. U. Nr 291, poz. 1712.) the limit values of the parameters that defines the deposit are: - the maximum documentation depth – to the depth of possible exploitation; - the minimum thickness of the deposit – 2 m; - the maximum overburden/thickness ratio – 0.5; the maximum content of grains bigger than 2 mm – 1 %; - the maximum content of ceramic marl with grains diameter bigger than 0.5 mm – 0.4 %; - the shrinkage in drying minimum 6 %.
The table given below shows reserves and the state of development and exploration of clay raw material for the building ceramics industry.
Anticipated economic resources amounted to 2,031.89 million m3 in 2012 (about 4,063.78 million tonnes) and increased by 9.54 million m3 (about 19.08 million tonnes).
There were 8 new deposits documented: Borów II in Lubelskie Voivodeship, Rakszawa-Pikor in Podkarpackie Voivodeship, Filipy, Wyszyna Fałkowska II and Wyszyna Fałkowska III in Świętokrzyskie Voivodeship, Marcinowo and Sypitki in Warmińsko-mazurskie Voivodeship and Rojów 2 in Wielkopolskie Voivodeship.
There were 16 deposits crossed out of “The balance…”: Lisów II in Lubelskie Voivodeship, Kalinów I, Mniszków and Quaternary clays from the overburden of Unewel-Wschód in Łódzkie Voivodeship, Mokre II in Mazowieckie Voivodeship, Pniów – Bera VII, Różniaty-Piątek V and Zarzecze 1 in Podkarpackie Voivodeship, Alina, Buków II, Grodzisko, Łąka II and Pacanów 2 in Śląskie Voivodeship, Wyszyna Fałkowska and Wyszyna Machorowska I in Świętokrzyskie Voivodeship and Guzy II in Warmińsko-mazusrkie Voivodeship. That resulted in the drop in resources – by 1.07 million m3.
Out of the total anticipated economic resources 13.4 % are resources within exploited deposits, 71.0 % are resources within non-exploited deposits and 15.6 % are resources within abandoned deposits.
Out of 1,235 documented deposits of building ceramics clays, 20.6 % of deposits are exploited (including 12.8 % deposits exploited continuously and 7.8 % - exploited from temporarily) and 25.4 % deposits are non-exploited (including 19.5 % deposits covered by detailed exploration and 5.9 % - covered by preliminary exploration). The remaining deposits were abandoned (54.0 %).
Economic resources within 140 deposits amounted to 147.26 million m3 (about 294.52 million tonnes) and decreased by 14.15 million m3 (8.8 %) in comparison with the previous year.
In 2012, production of building ceramics clays was equal 1.83 million m3 (about 3.66 million tonnes). It means significant drop (by 0.474 million m3 – 20.5 %) in comparison with the previous year.
The production in concentrated mainly in the northern Poland and within Mazowieckie, Świętokrzyskie and Pomorskie Voivodeship. These areas accounted for 83 % of total production.
The figure given below shows changes in domestic resources and production of clay raw material for building ceramics industry in Poland in the years 1989-2012.
Prepared by: Wojciech Szczygielski
Table 1. Building ceramics raw material - million m3