New recycling system with steel basin for TBN

TBN Transportbeton Nord GmbH & Co. KG is one of the leading producers of ready-mixed concrete in Northern Germany. The company is operating 13 production sites in the greater Hamburg area and Schleswig-Holstein. In addition to being a concrete supplier, TBN offers further services related to this construction material. Wishing to furnish its Lüneburg plant with a suitable recycling system for the residual concrete produced, the company turned to Bibko Recycling Technologies GmbH.

The mobile ComTec20 plant system supplied offers a recycling capacity in excess of 20 m³/h as a result of additional improvements and was also equipped with a full-fledged residual water purification system. The 3.2 m wide and 1.25 m deep hopper allows two truck mixers to unload simultaneously. In addition, the given width of the hopper makes it possible to feed material with a wheel loader. The installation of pipe connections allowed a flushing system to be installed on the hopper in order to keep it clean at all times and flush the entire material into the machine.

The residual concrete passes from the feeding hopper right into the machine, where solids ≥ 0.2 mm are washed out and discharged.

The interior auger, which is equipped with shovels and paddles, moves the sand and gravel towards the 3-m long spiral conveyor while simultaneously cleaning the interior walls of the trough washer by means of continuous scraping. At the same time, water is fed to the system from the spiral conveyor side so that the material is washed out using the countercurrent principle.

In the machine trough, sand and gravel are picked up by a bucket elevator and emptied into the transfer hopper of the spiral conveyor. The washed-out material can then be reused for concrete production in order to reduce resource consumption.

The mobile washout system was supplied with a sump and 4 x 3 x 2.9 m steel basin, which is used as an agitator tank for the resulting residual water.

Closed-loop material cycle achieved

In a first step, the excess water including the fines ≤ 0.2 mm is fed into a sump mounted on the machine. The sump is equipped with a pump, which pumps the water from the sump to the recycling water basin once the maximum filling level has been exceeded. The agitator installed in the basin keeps the fines in the residual water in suspension by means of cyclic agitation, thus preventing the residual concrete from settling.

The system thus achieves a closed-loop material cycle. The water containing the fines is fed back into the mixing process or used to rinse the truck mixers and hopper, thus ensuring a continuous cycle and, ideally, maintaining a constant water balance. This creates an economic benefit for the plant operator.

In addition to an economic benefit, the Bibko recycling plant also offers an ecological benefit: it contributes to reducing the use of natural mineral resources and avoids carbon emissions that would be generated by mining or quarrying these minerals.