Eszterházy Károly College Faculty of Natural Sciences
Kaolin (kaolinite, illite):
The kaolin has precious character dominantly consists kaolinite and illite. It is formed by the hydrothermal decomposition of sour igneous rocks, whereby the rock-forming minerals are converted into clay minerals. This phenomenon is usually accompanies the ore formation, even if the hydro thermals not include non-metallic components. The two clay minerals - kaolinite and illite - apart from each other may occur independently. Mainly used in the manufacture of porcelain (household, decorative and insulating porcelain). To increase plasticity they mix kaolin with feldspar. This is also used in paper manufacturing. In Hungary kaolin plants with economic importance were formed in the Zemplén Mountains, with the hydrothermal decomposition of upper Miocene (Sarmatian) rhyolite. The main kaolin mining centres were Szegilong and Mád-Bomboly. Pure illite were mined in Füzérradvány. The mining industry were stopped in the late 1980s and early 90s. The kaolin from Szegilong was mainly used as a filler for the paper industry.
Kaolin with hydrothermal origin may also be used as refractory clay, but because purity is not an essential requirement, clays can be sought which are more frequent and larger spreading of sedimentary origin, like clays which are rich in kaolinite. The clay minerals of these clays are formed by breaking down rocks, but due to the transport and multiple accumulation the original rock is not indentifiable. The sedimentary clays in addition of clay minerals contains quartz, feldspar, gypsum, carbonates, organic compounds may also contain pyrite and limonite. These substances can occur in the kaolin, but in smaller amounts. Refractory clay is used in the production of coarse ceramic, fireclay, fireplace tile, brick and ceramics. Refractory clay were mined in many places in Hungary, with partly open pit mining and partly depth mining. These plants had been largely depleted, mining has ceased. Today small local mining is at Pannonian or Pleistocene sites, which can meet the requirements for brick production. Mining also takes place at Felsőpetény and Sárisáp. The sandstone layers have multi alternate occurrence, on the top of the lower oligocene aged Hárs Mountain’s sandstone, occurs around the sites of Bank, Romhány, Felsőpetény (eastern part of Börzsöny Mountains). Lower Miocene land-based red-mottled clay was also used as an acid-resistant clay mined in Nemti (on the border of Heves and Nógrád counties). The refractory clay was accumulated in the Cserszegtomaj(Keszthely mountains) dolomite karst hollows. They use it as natural dye because of the iron oxide content.
Glass sand, foundry sand
White glass sand is formed at shallow sea areas with active waves where the pollutants (organic matter, clay, limonite) are washed out from the sand’s quartz. In the case of foundry sand perfect cleaning is not necessary but the sand must be absolutely carbonate free. Use: manufacture of glass, clear, white, 0.1-0.5 mm grain size of sand is used. In the foundry industry they use the sand to make foundry moulds. The optimal size of foundry sand is from 0.2 to 0.6 mm. The particles must be rounded in order to make the material more plastic and mouldable. The maximum clay content is 15%. In Hungary glass sand is formed at Fehérvárcsurgó(near Székesfehérvár) Triassic dolomite Pannonia sand settling series, formed at upper Pannonia river. It was subsided at the near shore of Pannonia inland sea, the coastal waves provided good leach. The mining industry currently operates. The best quality Pannonia age foundry sand is at Kisörspusztán (Balaton Uplands, near Kékkút). Pannonia age foundry sand also occurs at Bicske, Diósd, Sóskút, Tárnok (Dunántúli-Central Mountains., Budapest vicinity).
Bentonite is a rock which mostly consists of montmorillonite substrate mineral (montmorillonite – content > 50 percentage.). Montmorillonite comes into existence with the underwater (halmirolital) weathering of the tuff fallen to water. It is primarily used as a drilling mud, by the reason of its thixotroph feature. Accordingly concrete sludge pours in the meantime of drilling, it brings up bits of the drilling and it solidifies at the stoppage of drilling, it may not allow the subsidence of .the bits of the drilling and hinder the penetration of oil or gas to auger-hole. It is also used for defecation, filtration and remediation. It absorbs organic compounds. Since it is used for terminating environmental damage, it is also called eco-mineral. Due to its high melting point, it is an adhesive of foundry modules. Its Hungarian presence:
Mád (Zemplén-mountain): Here there are bentonite plantations which have sprung up in part with hydrothermal calciferous decomposition, partly with underwater weathering happened in warm thermal watering freshwater (limnic) environment. The initial point rock is upper-Miocene (sarmatian) liparite tuff. Istenmezeje (in Nógrád county) is a bentonite plantation that was arisen with the shallow maritime (halmirolital) weathering of bottom-Miocene rhyolite tuff. Domestic bentonite presences are merely cultivated periodically suitably for demands.
Diatomite (bergmehl, rock-meal)
Diatomite has arisen with the massive accumulation of microscopically sized vases of diatomacous-vased algae. (Diatom) Diatomite algae live both in freshwater and marine environment. Diatomite is utilized for manufacturing light building blocks (low density, loose, porous rock), for making insulators, chemical filtration, defecation, remediation.
At Erdőbénye (Zemplén-mountain) due to the volcanic activity in the upper-Miocene era, it sprung from vases of massively deposed diatomaceous algae in lake environment (Figure 7). Rock-meals mined here are burnt out and then are utilized for a vehicle of insecticide, chemical fertilizers. Mining is still in progress. The diatomite of high quality at Szurdokpüspöki (Mátra-mountain) from the middle –Miocene era, is particularly used for manufacturing light building material. Mining has already discontinued here.
The primary commodity which is known as zeolite, as a matter of fact is liparite (rhylitye) tuff of zeolite, inasmuch as zeolite –content exceeds 50 percent. Zeolites are cavernous crystal –structured aluminimum-hydrosilicates. They supervene in the gas-excavation of glassy pumice acebic pyroclastic rocks, with the metamorphosis of granulite-glass in the event of explosive outbreaks. Applications: fodder forage additive (it foments. nutrient –taking up) soil melioration, molecule filtration of chemicals, defecation, water purification, remediation of contaminated areas. Hungary is an appreciable zeolite producer on European level. Domestic zeolite presences could be found in the territory of the Zemplén mountain, eminently in the south part of the mountain. Zeolite mining also takes place currently from more surface cultivation.
Perlite has arisen with the glass-like solidification of acid, rhyolitic, drown lava. Its feature is that it contains 2-6 per cent hydrous (water) owing to it glassy appearance has evolved. Its SiO2-content is 70-75 percent.Perlite is primarily used in building industry. As an additive of lightweight concrete and plaster, for the purpose of heat isolation (lagging) and sound proofing. Bulbous perlite may be used as well as a chemical filter owing to its porosity. In bulbous state – due to its low density it keeps afloat and as a consequence of this it is also utilized for collecting oil pollution of water surface. Domestic perlite occurrences can be found in the north the Zemplén mountain. The most significant is the perlite solid figure at Pálháza, which is considerable, even on European level. Its mining is still in progress.
Dolomite is an important raw material in chemical industry and construction industry. Dolomite rock predominantly consists from dolomite mineral. From the respect of genetic processes primary and secondary dolomites can be distinguished. The quantity of primary dolomites is infinitesimal compared to the prevalent, generating mountain-like quantum of secondary dolomites. Dolomite formation primarily bound to hypersalin, far, thither lagoons, its separation directly precedes the separation of evaporates.
Secondary dolomites in engender in large quantum from maritime lime sludge in such a way that magnesium - dissolved in water - replace some parts of the calcium ions of aragonite or calcite. This replacement causes voltage in the crystal-lattice, as a result of divergent ion sizes, therefore due to (tectonic break) effect dolomite crackles and comes apart. In the fragmentation of the Transdanubian ‘friable dolomites’ spring water activity has also played a part. Finely ground dolomites are utilized as additives in building industry and for ceramics, but it is also used as scouring powder. The coarser grist of dolomite is a flux (substrata) in siderurgy, and it is the primary commodity of plastering mortar in building industry. In Hungary dolomite from the Triassic-age is a prevalent calciferous, it was and it is quarried (mined) in several places in smaller mines. The most significant mines are at Pilisvörösvár (Pilis mountain), at Iszkaszentgyörgy (in Bakony mountain), more at Alsótelkes (Hill of Rudabánya. Both cragged and friable dolomites are mined at Pilisvörösvár.