This dry process developed by chaeng for recovering metals from steel slag combines all the advantages of conventional processes:

1.Efficient and cost-effective metal recovery in the coarse range

2.Virtually 100% metal recovery down to the finest fractions range by means of optimised dry grinding, classification and sorting technology

3.Production of a high-quality mineral filler product with pre-cisely definable grain size distribution

4.The process is particularly suitable for Slag from the production of stainless steels

Following coarse slag processing line (recovery of metal e.g. + 20 mm, crushing of the mineral components to -20 mm) by means of crushing, screening and sorting technologies such as handpicking, sensor sorting, magnetic separation and/or dry density separation, a pre-crushed slag fraction is fed into the chaeng vertical roller mill.

Selective grinding and classification of the mineral fraction to the desired fineness, and treatment and pre-concentration of the metal content are performed simultaneously in the vertical roller mill. The range of fineness of the mineral fraction can be varied, thereby allowing fineness levels of -2 mm as well as 5,000 Blaine or more to be adjusted. The mills operating principle permits the utilisation of both the different levels of grindability and the different specific densities of the sub-stances contained in the grinding stock for separation.

While a defined filler product exits the mill through the classifier situated at the top of the mill in the direction of the filter and silo plant, a high grade metal fraction is discharged via a chute outlet in downward direction.

If the flow of metal does not yet achieve the desired purity of + 90% metal, further concentration stages by means of sensor, magnetic and/or density separation are installed downstream. In that case the non-metallic product of the sorting process is recycled to the mill. This way, it is possible to recover virtually 100% of the metal as metal product and 100% of the mineral product as precisely defined and metal-free filler.

The chaeng grinding process therefore offers the possibility of creating two marketable products in a single unit and additionally has the advantages of avoiding the necessity to treat the residual slurry that is otherwise customary in wet processes.