Home > Duo Group News > Equipment Division News
Originally supplying haulage for the Construction Industry, the business has recently diversified and in 2000 the company acquired a 10 acre site at Coleshill near Birmingham.
Originally a landfill site containing approximately 1 million tonnes of construction and demolition waste, KSD have for the past four years operated a crushing and screening plant utilising imported construction and demolition materials from the local area.
In 2004 with the aid of a government grant and a five year planning permission KSD decided to purchase a washing plant and process the on site material, Powerscreen Washing Systems of Coventry were successful in tendering for a state-of-the-art washing plant complete with a water management system.
Two of the main problems on site were the general lack of water and the inability to utilise lagoons due to the overall small footprint. This meant that a closed loop system was essential, the only water on site being a domestic supply.
Working within a small footprint PSWS designed and installed a Powerscreen washing plant that included the very latest technology including a complete water management system from their Italian partner Technoidea.
PRODUCTION PROCESS.
With production of recycled aggregates currently at 80-100 tph on site material is fed by excavator into the tipping grid of a mobile Chieftain tracked 1400; this machines acts as the primary screen facilitating the removal of more silt out of the material. The machine is unique in that it has a patented 11' x 5' four bearing "free floating" screen box which eliminates the need for any fine tuning; as the material passes through the integral screen decks it feeds left onto a folding side conveyor providing a stockpile of +40, a direct feed onto the second conveyor providing a stockpile of top soil and a third folding side conveyor to the right feeds to the latest design of Powerscreen Recycling Logwasher.
Capable of producing up to 120 tonnes of contaminant-free sand and gravel, the new Powerscreen Recycling Logwasher comprises an inclined trough fitted with two counter-rotating axles with high-tensile exchangeable blades and an elevated spray-bar system. The unit mixes incoming feed while milling and washing the material at the same time. Any lumps of earth or clay are broken down during this process and carried away in the wash water, while any lighter particles are floated off through specially designed outflow exits onto a 6 x 2 trash screen. Two spray bars are also mounted at the discharge end of the unit to provide a final rinse. Exiting the logwasher the material is then fed onto an 8 x 4 single deck vibrating part rinser, fitted with four sets of spray bars and polyurethane screen modules the material is washed and then fed onto a static T4026 inclined transfer conveyor which feeds the material directly onto the conveyor of a second "dry" Powerscreen Chieftain 1400 which again screens the material and delivers through its three integral conveyors to provide stockpiles of +40/+20/+10.
In the production process any material from both the bottom of the recycled logwasher and final part rinser is then fed into Powerscreen Fines Master 60, static sand recovery unit where it is classified and dewatered. Working for maximum sand grade flexibility, the Fines Master Compact 60 produces a combined total of around 60 tonnes/h; comprising a single 18" hydro cyclone, a centrifugal slurry pump, a collection tank and a high-frequency 8ft x 4ft dewatering screen fitted with 500µm polyurethane mats mounted on a single carrier chassis, the machine delivers one grade of course sand to stockpile.
As water management was an essential part of the project PSWS in conjunction with their partner Tecnoidea supplied a multi-plate filter press complete with 47 plates. Based on its impressive technical specification, quality of build and technical support, PSWS always work in tandem with Tecnoidea Impianti to offer a fully automatic silt management system that is specifically designed and sized to minimise operator input and maintain low running costs. As well as the press, the system includes the foul water pump, GFA automatic flocculent mixing and dosing plant, a SADF system which samples every 50 seconds, 6m diameter dynamic thickener tank with pneumatic discharge valve, sludge and fresh water tank; and all the support framework, structure, walkways and access platforms.
Once in the thickener the silt settles to the bottom of the cone and is pumped into the Technoidea press. When the press has filled and drained the water, it opens and the silt cake drops down into a concrete bay below; the press then automatically cleans itself ready for another cycle. As in any application, PSWS selects the correct size of press and takes into account such factors as the silt content, clay content and settlement rate of the raw material. The flocculent mixing and dosing system maintains a continuous supply of clean water and automatically mixes a batch of flocculent solution when the level drops. An operator only has to add the powder to a storage bin.
The installation of the new washing plant has been very beneficial as KSD can now sell three BS specified products of +20-40/+10-20/-10mm as well as a type ‘g' general building sand. This has provided new markets for the sale of these construction materials to national construction companies at a local level.
Additionally there are further potential markets in the sale of the dry silt cake which is now produced.
Commenting on the success of the project, Site Manager, Brinder Bullar commented
"We are very pleased with the materials that are coming off the plant, which are up to the high standards required by the construction industry. Our target was to produce high end recycled aggregates, which we are doing, the challenge now is to increase our presence in the market and establish recycled aggregates as an alternative in newer markets such as concrete batching."