The ever increasing price for raw materials and our customers’ desire for independence from international resource suppliers was the driver behind our newly developed process to recycle grinding sludges from the metal industry.
Until now it has been usual to mechanically separate the oil and press the metal swarf with the remaining oil afterwards. But the emerging low-grade briquettes with more than 5 % oil content are inappropriate for high quality further smelting processing.
In contrast with VacuDry® water and oil are physically separated in a distillation process with temperatures up to 400 °C and under partial vacuum down to 20 mBar (abs). The result is a high grade metal dust with oil content less than 0.5 %. The absence of oxygen during the process prevents oxidation and therewith changes of the chemical structure of metals and alloys. The common expensive reduction in a blast furnace or electric arc furnace is not necessary. In the following steps the metal dust, in combination with cement is grouted in oil free metal briquettes, smelted and returned to the recovered substance cycle.
Especially for high-alloy steel the VacuDry® process is very profitable. The plants provide capacities from 5.000 t up to 40.000 t per year.