In November 2006 a CDE Sand Washing Plant was installed with the Sampete Group based in Wallerfield Armia, Trinidad. Before this installation the raw material had been stockpiled as waste, compromising the efficiency of several limestone quarries in the east. It provided a considerable challenge for traditional systems as it is overburden mixed with clay-bound material which is extremely plastic in nature. The feed is heavily contaminated and often up to 50% of the minus 5mm material can be less than 75 microns.
The new CDE plant significantly delivers consistently high quality sand from this raw material, generating maximum commercial output. Once again proving that traditional barriers to washing difficult materials have been relegated to the past with CDE's innovative washing system.
Sand slurry leaving the primary screen is piped to the new CDE compact sand plant which is rated at over 100tph. This plant has no trouble in handling the high clay volumes (up to 50% in the sand fraction) in the feed. Slurry is fed directly into the sump and is then sent to the custom sized hydrocyclone by a Warman pump. The silt cut point can be set to suit customers' specific product requirements but here the sand consistently contains less than 3% minus 75 microns. From the base of the hydrocyclone the sand is fed on to the high efficiency dewatering screen and is discharged over a rubber-lined chute to a conveyor for stockpiling at less than 12% moisture content. The waste water containing the clays pass directly to an 8m diameter CDE T-08 High-Rate thickener complete with a fully automatic Polyelectrolyte dosing station for further treatment.