Amberger Kaolinwerke has been mining raw kaolin earth in Hirschau-Schnaittenbach since 1833. These consist of three minerals: kaolin (15%), feldspar (10%) and quartz (75%). A state-of-the-art sand plant was erected and inaugurated at the Schnaittenbach site in 2016. The sands are used in particular in the glass and construction industries. On account of their rare quality of being coarse yet very round, they are also valued as filter sands.
One of the most important continental kaolin, silica sand and feldspar deposits in Europe is situated in the kaolin field in the Hirschau-Schnaittenbach basin.
The genesis of the Hirschau-Schnaittenbach deposit started about 250 million years ago in the so-called Middle Buntsandstein stage (Lower Triassic). In this period, the basin situated here was filled with the erosion debris from the areas to the south and south-east, consisting of granite and gneiss. Acidic water then decomposed the feldspar and mica components to kaolin. The special feature of Hirschau kaolins is there extremely pronounced lamellar shape.
The Quarzwerke Group uses state-of-the-art technology to separate the raw earth into the industrial minerals kaolin, feldspar and silica sand. This takes place through classification into various grain fractions by means of washing cylinders, cyclonic cascades and centrifuges. This is followed by dewatering through sedimentation, filtration and drying. Individual kaolin products are additionally refined by bleaching and magnetic separation.
Although kaolin in particular is well-known from opencast mining, feldspars are also produced with consistently high quality at the dual site of Hirschau-Schnaittenbach. State-of-the-art processing with the process stages of washing, flotation, drying and magnetic separation ensure this. The potassium feldspars produced from the feldspar sand have a high degree of purity in terms of the iron and titanium content and are characterized by a high total feldspar content.