To contribute towards improving the environment, the ELKON reclaimer has been developed. This can be used on either wash water from the plant or surplus concrete from returning truck mixers, and separates the light cement/water mix from the denser sand and gravel mixture. Economical and compact, it is quick to install with minimal site preparation ? basically prepare the level site, assemble it and connect water and power supply, then ready to run.
The hourly capacity is around 10m? of concrete ? ie mainly solids with the water added into the mix so actual solids will vary with moisture content of the mix. Depending on the mix recipe and amount of water used to wash out the plant/truckmixer/pump, estimated solids content would generally be in the region of six to eight cubic metres (6-8m?) per hour. This system separates the cement, in a reusable slurry form, from the aggregates and sand, which may be re-used as a mix, or rescreened into individual sizes, as required.
For larger and more sophisticated operations, Rocktec has its own Redi-Wash, an extendable, modularised system, designed for large facilities utilising up to 45 truckmixers.
The Redi-Wash system is the most proven, rugged and comprehensive truck mixer washout system available, being simple to install and operate, with minimum replacement parts and operating costs. Couple this with the savings that can be made on existing operations and it makes this the most cost effective investment for sustainable operation of concrete plants today.
The design was originally conceived in 1969 in the USA and while the product and its components have evolved, the basic principles and the success (and payback) for the concrete plant operator have remained constant throughout.
{{image2-a:r-w:250}}Redi-Wash is capable of reclaiming all of the concrete materials being washed out of the truckmixers, and provides recycled clarified water for the washouts from within the machine. A washout is generally completed within four minutes, separating sand and aggregate from cement, with an optional built-in screen providing further separation.
The Redi-Wash unit becomes the basis of an environmentally correct yard, and eliminates yard surface water, requiring no settling ponds or discharge to waste and reduces fresh water intakes on existing plant. These are major benefits when submitting planning applications.
As well as the benefits to the environment, the ability to reuse valuable resources significantly reduces operating costs and provides proven payback each year over many years.
Operationally it is very simple and is usually run by the truckmixer driver, with no dedicated personnel necessary. When the truck returns to the yard with waste or residue concrete, it reverses onto the Redi-Wash and undergoes a thorough washout and rapid discharge into
the Redi-Wash.
The truck moves off and is available to pick up a new payload and deliver to the next site. The payload can be a completely different mix with no risk of recontamination from previous load.
The waste concrete slurry is rapidly discharged from the mixer into the reclaimer stage, where a paddle conveyor system tumbles and agitates the material under thousands of litres of water to release the cement. The cement is held in suspension in the water in the first stage. The sand and aggregate fall to the bottom to be washed further and are reclaimed and discharged from the machine onto a belt conveyor.
The mixture can be separated into sand and aggregate by a screen (optional) at the end of this belt conveyor. The conveyor discharges into a separate bunker where the sand and aggregate are stockpiled.
The reclaimed cement and fibre additives are held in suspension in the water and transferred to the clarifier stage, which is a controlled water clarification environment resulting in a thick cement by-product being discharged into a separate bunker as a stable damp material that a front end loader can handle.
The clarified water returns to the Redi-Wash in a closed circuit loop ? the high level of water recovery minimising any need for top-up water, as well as eliminating water disposal or after-treatment issues.
Source: Rocktec Australia