Crushed stone and gravel works are finding it increasingly important to process the rubble collected during prescreening, involving cleaning it and converting it into marketable products such as high-quality limestone granulate or different kinds of aggregates for use in construction products. With Allgaier dry processing using the SYSTEM TRH dry cleaning drum, it is possible for limestone cleaning to take place without water, and in an especially energy-efficient process. Contaminated material no longer has to be dumped, and old spoil heaps can be recycled.
Cleaning combined with drying the minerals mean that expensive stone washing can be dispensed with. There is no need for a separate stone washing plant to be purchased or for such a plant to be operated (which entails high levels of water consumption and subsequent expensive water processing). Also, the energy consumption for drying the limestone is minimised, because the natural moisture content of the prescreened stone is lower than the moisture level of the stone after washing. When limestone is washed, it absorbs additional water, which has to be removed again by drying, involving significant use of energy.
The simple and effective solution for cleaning stone means that Allgaier saves quarrying companies the need to use washing processes, thereby allowing them to access wide-ranging savings:
- Reduced apparatus costs
- Low operating and energy costs
- No water consumption
- Minimum maintenance costs
Dry cleaning is also advantageous if the operating company wants to avoid the washing process due to the considerable expenses involved in obtaining a permit for the water use, processing the water, filtering and dumping the sludge.
DRYING AND CLEANING
Drum dryers for simultaneous product cleaning have an area in the inside of the dryer in which the solid material is rubbed against itself to an increasing extent.