Steel mill scale was mixed with other wastes and additives (molasses, carbide residue, hydrated lime, post-sodium lime, burnt lime, waste from the ingot casting machine, post-grinding sludge waste, blast furnace dust, coke and fine coal) and briquetted in a roll press to optimize the compn. of the raw material and to develop a method for prepn. of the briquettes. The preferred amt. of mill scale in the feed was 76-91% and the feed humidity 1-3.5%. The recommended circumferential speed of the rolls was 0.3 m/s, a gap between the rolls 2-4 mm and a unit pressure 72-125 MPa. Gravity dosing was found sufficient, but the screw feeder allowed to actively influence the process. The saddle shape of the briquettes was more favourable than the classic one.