8/13/2019 Paper News 2-2012 English

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8/13/2019 Paper News 2-2012 English

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Readymix Abu Dhabi

Readymix Abu Dhabi are one of the leading manufacturers of ready mix concrete in the UnitedArab Emirates. Two of their five plants BIBKO have recently been entrusted with the supply anddevelopment of appropriate recycling systems for the recovery of residual concrete.

The following description covers all technical details of the concept.

For the large facility BIBKO has been charged with the supply of a ComTec residual concreterecycling system, a pump discharge conveyor, a dosing buffer and a filtration press.

The solution elected for the concrete pumps was a pump discharge conveyor. Concretepumps can be emptied easily and without delay into the ground-level hopper. The residual mate-rial, consisting of concrete residue and wash water, goes into the downstream dosing buffer.

Thanks to the high performance upstream dosing buffer added to the ready mix reclaimerComTec 30, the truck mixers can discharge the concrete intermittently. The dosing buffer is atrough of a length of 5 meters receiving about 6 m of residual concrete within a short time. Thisway waiting periods for continuous filling of residual concrete can be dispensed with. In addition,several mixers can wash out and discharge concrete simultaneously at the feeding hopper of awidth of 10 m.

Residual concrete and washing water are buffered in the dosing unit. The residual concrete is lif-ted inside closed buckets via a cylindrical screw conveyor which is surrounded by a semicirculartrough. The buckets empty water and residual concrete on the feeding chute into the downstre-am ready mix reclaimer. The water containing fines of < 0.2 mm is transported into the alreadyexisting agitating basins.

These agitating basins serve as intermediate buffer for further conveyance into a filtrationpress. Since this residual water is not utilized within the agitating process the water has to befreed from the fines in order to allow its reutilization as clear water in the concrete plant after-wards. If, inside the residual water basin, the water level and the density measured are excee-ding the permitted levels, some of the recycling/residual water will automatically be transportedto the filtration press.

The automation of the process saves the producer from operating manually. The residual wateris pumped into the filtration press for clarification by means of an increased pressure obtained

by the special compressed air diaphragm pump. At this stage the amount of water contained ispressed out of the sludge by special filter cloths. The clear water obtained this way can after-wards be collected and fed again to the agitating or production process. The sludge produced atthe same time is kept inside the press until its full. Then the press will open/be opened, auto-matically or not, depending on the type of unit. The sludge cake produced by the water clarifi-cation process can simply be disposed of.

Filtration presses are available in various sizes and designs. Please note, that there are filtrationpresses with manual sludge discharge and presses on which discharge activated automatically.

The above concept has also been implemented in the smaller ready mix concrete plant, howeverwithout using a dosing buffer.

8/13/2019 Paper News 2-2012 English

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