General Characteristics of Diatomite
Diatomite is white, loose or choke-like, sometimes smoothly stratified or slaty sediment made from piling up the frame of diatomaceous algae. They have variable forms: needle, rod, disc, triangle and/or quadrangle. Algae live both in salted and fresh water.

They extract the silica required to build up their frames from the water, so the vast majority of utilisable diatomite reserves are connected to vulcanic regions. Silica relatively easily dissolves from vulcanic glass and tuff at the hydrolitic disintegration of feldspar, and silica is released at the mineralisation. Under these circumstances resupply of the silica is secured, so the life-conditions of diatomaceous algae.

During their life algae molt their armours. Whit the change of biotope they may perish in masses. In addition to this diatomacae serve as main source of food for many species. Silica armor as non-digestable material goes to the sludge. These factors result in the piling up of diatomaceous armor, and creation of even more than 10 meter wide diatomite sediment.

Physical characteristics of diatomite can be origined from special structure of silica armor. Its porosity is very high and its specific weight is low. Specific weight is 2.1-2.2 g/cm3. Its melting point is about 1,610-1,750ºC. It is resistant to acids, dissolves only in hydrofluoric acid. If annealed in aery environment (600-800 ºC) organic materials burn.

Characteristics of Diatomite from Erdőbénye
This sedimentive rock with organic origin consists of mainly diatomaceous algae and there are signivicant reserves at Tokaj Hill region. It has been created in a fresh water basin and the neghbouring area about 12 million years ago in a territory of 25 km2. In the middle section of the hill some diatomite fields were explored on rhyolite tuff base rock in parallel with other valuable industrial materials (bentonite, perlite, pumice, quartzite, limnoquartzites, and zeolites).

Exploration has been started around 1890s, but it became significant only in the 1950s, when new usage forms created demand for the diatomite. Production site has been built in Erdőbénye (dry and wet grinding, powdered drying, and calcination) and the annual production was around 25,000 ton in the 1980s, 22% of which was exported in average. Currently this ratio exceeds 50%.

SEM picture of diatomite from Erdőbénye

Composition of the diatomite mined in Erdőbenye
Below you can find mineral and chemical composition of diatomite from Erdőbénye, as well as, physical characteristics.

mineral composition
chemical composition
Mineral Portion [%] Compound Portion [%]
Amorphous diatomite 75-85 SiO2 78-85
Montmorillonite 6-8 Al2O3 3,6-8,5
Quartz 1 Fe2O3 0,5-3,6
Feldspar 1-2 TiO2 0,1-0,3
Calcite 5-6 CaO 0,6-1,8
Aragonite 3-4 MgO 0,3-0,6
    K2O 0,3
  Na2O 0,1-0,2
physical characteristics
MnO 0,063-0,071
Characteristic Measure SO2 0,01-0,05
Specific weight [g/cm3] 2,1-2,2    
Volumetric weight [g/cm3] 0,7-0,8    
Literweight of grinded diatomite [g/l] 190-280    
Porosity 0,66-0,69    
Whiteness [%] 60-67    
Melting point ºC 1500-1580    
Specific surface [m2/g] 110-162    

Main usages of diatomite
- brewery,
- wine-making,
- pesticide production
- fruit juice production,
- vegetable-oil production,
- water treatment,
- titanium-dioxide production,
- Pharmaceutical industry.

As filler
- paint making,
- abrasives,
- agriculture,
- catalyst,
- paper making,
- insulation technics,
- Portland cement.

Spillage control
- Environmental protection,
- dangerous waste treatment in case of spilling or other wreck,
- anti-skid utilization
- pet litter

- production of fire- and wear-resistant internal coverage of aluminum- and steel industry heating ovens
- Production of parts of glaze, enamel and glass industry melting furnaces
- insulation of pipe systems of power plants, as well as, metallurgical machinery
- Heat-insulation
- nuclear power plants, isotope laboratories
- manufacturing of medicinal products, cosmetics (due to its high mineral content and absorption capacity)