Kaolinite clays called as refractory clays are an indispensable raw material for production of fire resistant materials. Such clays originate in result of wash down of outcropping and near-surface kaolinized rocks and redeposition of kaolinite, connected with separation of quartz grains and marked improvement of fire resistance properties of that raw material.
Kaolinite clays are characterized by high plasticity and when fired at temperatures over 1,500oC they form ceramic bodies with high mechanical strength. Very low content of calcium and magnesium compounds is very advantageous as it results in a rise of melting point of these clays. In turn, presence of iron compounds results in yellow to brownish and red color of the refractory clays.
The single exploited deposits of refractory clays (the Rusko-Jaroszów deposit), is situated in the Lower Silesian region. The second largest deposit is called Kryzmanówka and is located in the Mazowieckie Voivodeship. This deposit was not exploited in 2013.
Refracotry clays deposits are presented on the map.
Table 1 shows the current state of exploration and development of the fireproof clay resources.
Anticipated economic resources amounted to 54.56 million tones in 2013 and were by 0.09 million tonnes lower than in 2012.
Economic resources are equal 2.62 million tonnes (4.8 % of total anticipated economic resources and 56 % of anticipated economic resources within exploited deposits).
In 2013 production of refractory clays was equal 87 thousand tonnes and decreased by 5 thousand tonnes in comparison with the previous year. The exploited raw material may be used without any processing or after firing, as the so-called “fired clays”.
Prepared by: Janina Dyląg