Recyclable foundry residues includes substantial proportions of slag from non-ferrous metallurgy and from stainless steel production.

Slags are formed as waste or by-products of metallurgical smelting processes and are created from largely homogeneous smelts that consist of free or bonded oxides. In their solid form, they often contain larger chunks of metal or coated metal particles. In this case, reconditioning with the aim of recovery of the metal content is worthwhile – as also is the regeneration and re-use of the bonded chemicals in the metallurgical process.

Example: The salt slag created during secondary aluminium production contains 5-10% aluminium, which can be easily recovered through the correct processes. Additionally, the salts used in the formation of the slag can be recovered through technical processes.

The coated metal parts can be recovered viably by dry mechanical methods following appropriate crushing and grain classification. This task of aluminium separation is performed by our STEINERT EddyC® and STEINERT EddyC® FINES eddy current separators efficiently and reliably. Thanks to its separating splitter mechanism, precisely adjustable and optimised for the drop parabola of the material stream, the STEINERT EddyC® FINES is particularly suitable for separating the fine grain sizes up to 0.5 mm necessary for the crushing. Combined with the trusted high-frequency pole drum with its eccentric construction, the highest yields and purity levels can be achieved.

In the reconditioning of slag from stainless steel production, our STEINERT MTE electromagnetic drums or STEINERT MTP permanent magnetic drums with neodymium magnets are used for separating and concentrating the ferromagnetic slag components.

For concentrating other metallic content, e.g. in stainless steel slag, the STEINERT ISS® and Steinert KSS sensor sorting units are most suitable. The selective ARGOS-type induction sensor can be adjusted variably and precisely for the optimum product generation. The multiple sensor system of the STEINERT KSS combination sorting system achieves an additional product improvement, depending on the condition of the material.

Apart from slag, used sand from foundries responds excellently to dry mechanical regeneration and can be re-used. Here again the STEINERT EddyC® and STEINERT EddyC® FINES non-ferrous metal separators are ideally suited to the separation of metal content added during the casting process.