Purity requirement for medium grain sizes
A special challenge is currently the processing of large quantities of fireclay bricks supplied by a globally operating client from the refractory industry. The material is temporarily stored in the recycling plant and crushed on demand. The fireclay bricks are 400 to 500 mm in size and are fed in via a Metso Outotec Lokotrack LT106 jaw crusher and processed into 40/45 mm grain sizes.
The Lokotrack was specially equipped for this purpose with particularly magnetic crushing jaws, whose wear is higher than with manganese. Background: The client places high demands on residue-free crushing and is very careful to ensure that no metal particles contaminate the end product. Since there is always a lot of wear on crushing jaws, Karl-Werner Bierbrauer has taken precisely this circumstance into account and ensured that only particularly magnetic residues can enter the crushing process. A correspondingly strong magnetic separator pulls the wear material out of the crushing process all the more reliably after crushing. The machine was specially reserved for this recurring contract work and is thus exclusively reserved for fireclay preparation.
The customer then takes over the pre-crushed material to further break it down into smaller fractions and screen it on his own. “At the time, it was very difficult for the company to find a processing partner who could store the expensive material in a dry place, weigh it precisely and process it cleanly,” says Karl-Werner Bierbrauer. “You could almost call an articulated lorry with an average of 25 t of this material a value cargo as soon as it leaves our company. That’s why it’s not surprising that a laboratory technician from the client continuously monitors the processing as well as the end product.”
The refractory rock is broken out of the casings during processing in the LT106 jaw crusher. The sleeve is pressed in via the appropriate setting of a generous crushing gap, although it is not completely crushed. At the end, the magnetic separator pulls it out. “You have to imagine it as if you were pressing a tin can in a controlled way to get rid of the contents completely. All batches are individually numbered, labelled and must not be mixed together.”
Tree and lawn substrates with lava
Pumice, tuff ash, lava and basalt are the main components of the soils in the Eifel region – where Karl-Werner Bierbrauer’s quarry and recycling site are located. Recently, the company has been engaged in the production of substrates whose components are made up of the regional minerals. Partly lava from the company’s own quarry is used, partly – depending on the objective of the production – light or heavy lava material is bought in. Bierbrauer & Sohn produces tree substrates for planting pits that cannot be built over in the fractions 0/16 and 0/32 mm from lava rock. For this purpose, topsoil is mixed with lava and screened using the mobile Lokotrack pre-screening unit ST2.4 from Metso Outotec or a corresponding 35 square mesh. On average, about 9 m³ of material is needed for a tree pit, whereby appropriate substrates must above all be able to store the corresponding amounts of water and air.
Another component of the new company portfolio is the 0/8 mm lawn substrate, a mixture of topsoil, lava and appropriate compost components. It can be used to lay rolled turf or to sow lawns. Product manager Ralf Beissel says: “We pass this material on to garden and landscape builders unfertilised. Pumice is often an integral part of the substrate or part of the topsoil, as we only process pumice-containing soils from the region. Lawn substrate needs 35 % water storage, the compost content is correspondingly high. At our quarry in Ettringen, we draw on our own laboratory to independently test grading curves, water storage and all important components of the substrate for reliability.”
Bierbrauer & Sohn GmbH has maintained close business relations with the Metso Outotec dealer Fischer-Jung Aufbereitungstechnik GmbH from Krefeld for 9 years already. The family business and its sister company Terratec-Basalt GmbH now operate a total of 24 mobile plants from Metso Outotec. “I can only praise the cooperation with Fischer-Jung Aufbereitungstechnik in the highest terms – on the one hand, on the service side, as far as the training of our personnel is concerned. On the other hand, we are always supplied punctually with the necessary spare and wear parts. We stock up annually with crushing jaws, impact bars, the necessary screws, crushing shells, crushing cones and screen linings. We benefit from more favourable purchase conditions when we plan a year in advance. Since we are also permanently required in the area of contract crushing and screening, the stocking of spare and wear parts is vital for us.”
Soil preparation for construction development
Karl-Werner Bierbrauer is currently preparing another 6 ha plot of land, which he calls a technical construction site and which he is building up with an additional 500 000 t of soil in sandwich construction. The entrepreneur is redeveloping the plot by bringing in his own recycling and soil material as well as with further soil stabilisation measures, in order to sell it later to investors ready for construction. Delivered construction waste for the backfill runs directly over a mobile scale on site and is then processed into RC using a Lokotrack LT96 jaw crusher from Metso Outotec with hydraulic crushing gap adjustment and a heavy-duty ST2.5 screening plant.