ABEL HMT – Transfer of abrasive tailings through long distance pipelines
At a copper processing plant in Zambia classified copper tailings from a thickener and cyclone installation have to be transferred over a distance of 3.5 km to an underground mine where it will be backfilled. The quantity of dry solids is 70 ton per hour.
An ABEL triplex single acting piston diaphragm pump (HMT) was installed for the transfer of these tailings. The solids concentration in the slurry is 50%. The investment in a piston diaphragm pump needs to be protected against a number of potential risks. In the ABEL pump therefore, the gears are forced lubricated in order to enable low stroke rates. Also the pistons are lubricated to avoid overheating. The pump diaphragms are protected against overstretching by a reliable mechanical stroke monitoring system. In addition, the pumps are equipped with pulsation dampeners which dampen pressure fluctuations, thereby protecting the pump and the piping system.
Since start up of the pump the operating costs have been extremely low: Due to the high efficiency of the HMT, the absorbed power at 90 m3/ hr (390 GPM) and 50 bar (725 PSI) is less than 160 kW. The spare parts consumption of the HMT, is limited to the exchange of the valves every 5000 to 7000 hours. The diaphragms are replaced every 12000 to 16000 hours for preventive maintenance. ABEL piston diaphragm pumps offer low operating costs due to the physical separation of the abrasive slurry from the pump’s main moving parts by premoulded rubber diaphragms. Only the product valves on the suction and discharge side and diaphragms are in direct contact with the slurry.
The reciprocating principle of the piston diaphragm pump ensures a very high mechanical efficiciency of >93%. Consequently, the pumping costs are minimal and make the operation of this type of pump very feasible when compared to more conventional methods of slurry transfer.