From sludge to sand in eight cylinders

In quarries where materials are processed using water, the resulting fines are recovered in the form of sludge. Because of their volume, and the difficulty and cost of recycling them, we needed to find a technical improvement that would reduce their volume at the processing stage. This is a particularly tricky problem in maritime work given the small size of the processing platforms, which are located in ports.

After laboratory tests and a study focusing on the possibility of recycling the fines, a “cyclone” manufacturer (machines for separating solids from liquids) was asked to find a way of recovering very small fines according to supplied specifications. The manufacturer suggested adding eight “micro-cyclones“ to the existing equipment, allowing fines of between 25 and 63 microns to be recovered and reincorporated into the product sold. Another benefit is that either all or just a certain range of the 0-25 micron fraction can be reincorporated, depending on the product.

Use of the new equipment has generated a double benefit: the volume of sludge is reduced by 40%, leading to lower transport and evacuation costs, and the use of recovered fines generates more product for sale. This has led to a sharp improvement in the company’s competitiveness and the innovation has already been transferred to the new Graves de Mer facility in Dieppe (Seine-Maritime).

This process was awarded a Sustainable Development prize in the Materials, Processes ans Techniques category.

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