CDE and EUROVIA to host demonstration event in Slovakia
Eurovia – Kameňolomy, s.r.o, part of the VINCI Group, will partner with CDE to host an Open Day at their Quarry Dubná Skala near the city of Martin in northern Slovakia on 6-7 june 2017. The company will showcase its new CDE 60 t/h wet processing plant, which will supply materials for a major motorway construction project over the next three years.
Eurovia has a large presence in Slovakia where it produces aggregates in 10 rock quarries and one sand & gravel plant. The CDE wet processing plant was installed in 2016 in the Dubna Skala Quarry is based near the city of Martin in northern Slovakia. The main product from the quarry is a 0-4 mm crushed granite. Eurovia supplies concrete for urban development and road projects, including a major road construction project to develop an 11 km stretch of the D1 highway between the cities of Martin and Zilina, which is currently under construction with work continuing until October 2018. This project has a budget of 427.2 million € and comprises 11 bridges and two tunnels so the requirements for aggregates is ongoing and significant.
The Project
The Dubina Skala Quarry is an 100 year-old granite quarry situated in rural Slovakia. Due to the remoteness of its location and the lack of access to a water supply, the customer needed their new wet processing plant to have a low energy requirement and to be able to recirulate the water through the system. Eurovia’s main objective was to turn an unsaleable 0-4 crushed granite sand fraction due to high levels of contamination (contamination of 0/0,063 mm fraction in the feed material at a range of 8-9 %) into a high value product. As the quarry is located at the top of the mountain and has limited access to water supplies, ridding the granite of contaminants was challenging.
During a process of co-creation with Eurovia, CDE prepared a bespoke design for a modular installation that would fit the limited space available on the quarry whilst addressing water efficiencies and significantly increase product quality.
CDE Solution A first within the region, the Eurovia CDE installation comprises an EvoWash 71 wet processing plant, an A200 AquaCycle thickener and a Filter Press. The plant is completed by a buffer tank, an AquaStore and a FlocStation. Jaroslaw Modrzejewski, CDE Area Sales Manager for Poland, the Czech Republic and Slovakia explains: “This is the first full water treatment plant in this region. It solves the problem which all other quaries have experienced and struggled with: what to do with the final fraction 0-4 mm which is heavily contaminated with dusts after the crushing process? Eurovia have now positioned itself as the leader in this field and we are proud to have achieved this project as a reference site in the Slovak and Czech market.”
Commenting on Eurovia’s specific need for a low water requirement, Modrzejewski adds: “Our plant uses only a few cublic meters of water per hour, which allows EUROVIA to wash its low value product and turn it into high value washed crushed sand, opening up new markets for the company.”
Plant Process
The extracted dry material travels by conveyor to the feedbox from where it enters the sump of the EvoWash 71. From the sump the sand is pumped to a cyclone which separates the material into the required size, with one of the key benefits of the EvoWash being that it does this without losing fines materials. From the cyclone the washed sand is sent to a dewatering screen and after further dewatering on the screen the 0-4 mm sand travels by conveyor and forms a stockpile.
The fine material sized under 63 µm is send to the AquaCycle thickener. In the AquaCycle a small amount of polyelectrolyte floculant is added to the water from the automatic dosing station which forces fine particles to settle on the bottom of the thickener tank. The clean water on the top overflows the weir and is stored in the AquaStore tank before being re-circulated around the plant again, helping to reduce the amount of fresh water required. The waste sludge is discharged into a buffer tank where a motorised rake in constant rotation ensures the material does not settle and solidify. The sludge is held in the buffer tank before begin processed to recover more water in the Filter Press.
Following testing of the materials it was determined that the Side Beam Filter Press required 36 of the 800 mm2 plates to achieve a processing rate of 3 t/h. Currently the Filter Press is completing 4 press cycles per hour. During each cycle the filter plates fill with sludge and are compressed under high pressure to remove moisture, the waste material, a dry filter cake then drops into a holding bay from which it can be easily transported and stored.
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