The Loesche Mill for the dry-processing of steelworks slag to a high-value construction material and with almost complete metallic recovery

Loesche installs the first dry-processing plant for stainless steel slag.

Charleroi – Together with CALA Aufbereitungstechnik GmbH & Co. KG, Loesche has developed a dry refining process for stainless steel slag (EDS) to obtain a high-purity metallic portion and a valuable, metal and mineral-free filler material at the same time.

The Loesche Mill for the dry-processing of steelworks slag to a high-value construction material and with almost complete metallic recovery

Loesche Mill for dry metal recuperation and filler production from
stainless steel slag

The innovative Belgian company RECOVAL, located in Farciennes, assigned Loesche with the engineering and delivery of a turn-key processing plant primarily for stainless steel slag.

The background requirement for this special plant technology is, amongst other things, a patented development of the consortium comprising Recoval bvba, Recmix bvba and Carbstone Innovation NV for the recovery of construction material from slag. In this novel recovery process and purely by the addition of CO2 to the EDS, finished components with structural properties like those of concrete are produced without the use of conventional cement. Thus it is possible to produce parts which effectively represent a reduction in the world CO2 content, whereas concrete components have a CO2 footprint which lies above 300 kg/m³.

The Loesche Vertical Mill type LM 15.2M will be at the center of a newly-built processing plant for the manufacture of such components in the district of Charleroi in eastern Belgium. Around 20t/h of stainless steel slag will be processed in this specially designed mill. In the mill the slag will be selectively ground to free the metallic particles which are then extracted as a high-density fraction. Simultaneously, the mineral fraction as a filler material will be separated in the integrated dynamic classifier at the desired fineness and collected in the filter unit. The grain distribution of the filler product can hereby be chosen freely without negatively influencing the maximized extraction and high quality of the metallic portion.

In the second part of the plant the metallic, high-density product of the mill will be further processed. Using a combination of magnetic separators of varying field strengths and a novel, dry, density-based separation unit for the fine fraction, the pure metallic portion will be recovered and the intermediate residue fed back to the mill.

The silo installation is accessible from below by truck and additional silos are part of the third complex. The filler products will be stored here. A separate storage and filling system is planned for the metallic portion.

Loesche GmbH is responsible for the engineering, the delivery of the hardware and the erection and commissioning of the equipment. The complete electrical equipment and technology will be supplied by the Loesche Automatisierungstechnik GmbH.

With the new plant technology for this ecologically extremely challenging project, Loesche will be providing the energy-efficient dry grinding and preparative technology. This is again proof of Innovative Engineering with a combination of ecology and economy.

The flexibility of the plant allows not only for variations in the product quality of the filler but also allows for the other raw and remaining materials to be sent for further sorting or recuperation.

The operator has the goal to apply the potential of selective grinding and dry classification to other primary and secondary raw mineral materials such as fire-resistant cement, other slags created during the iron, steel and steel-alloying processes as well as for ores and industrial minerals. Thanks to the flexibility of the Loesche vertical roller mill and the comparable plant planning, a quick change of materials during operation can be accomplished without problems.

Thus, in close cooperation with RECOVAL, a production plant will be built which allows the creation of grinding products and metallic fractions which RECOVAL need for other processes.