In the past, some Dorfner sand had to be passed through the processing plant twice in order to optimize the residual fine material content. Although this increased the quality of the sand, the effort was immense and could not be applied to all sand production.

For this reason, we looked for a way of optimizing the existing process to produce optimal quality from a single wash. After-washing in centrifugal separators for liquid mixtures, so-called hydrocyclones, was identified as a solution and implemented as part of a project. Since July 2019, newly integrated into production, the two-stage hydrocyclone system has successfully cleaned the sand of all unwanted fine substances.

In a cycle

The sand (approx. 90t/h) is washed with 300m3/h water. The fine substances are then removed from the wash water with a thickener. This means it can be reused in a way that conserves resources. Virtually no additional fresh water is required. The separated fine fraction – which is essentially kaolin and feldspar – can be processed into high-quality products.

The optimization has saved around 40,000 liters of diesel and around 250,000 kWh of electricity per year. This corresponds to an annual reduction in CO2 emissions of 240 t.

Thomas Gernhuber