The present invention relates to a process and to a system for eliminating the expandability of steel-plant slag, which comprises a primary crusher (3) to reduce the fragments according to their granulometry; a magnetic separator (4) to remove metallic fragments bigger than a determined granulometry (5); a rotary dryer (6) to dry slag free from bigger metallic fragments; an impact mill (11) to disaggregate and fragment slag particles that are bigger than a predetermined granulometry; a classifier (12) for aero-classification and drag of fine and superfine particles; a cooler (17) for cooling slag particles bigger than a predetermined granulometry by means of heat exchange and removal of the fine and superfine particles that were not collected by the impact mill (11); a vibrating sieve (21) provided with two or more decks (23, 24, and 25) with screens of predetermined sizes; low-intensity magnetic separators (26, 27 and 28), with generation of non-magnetic slag fractions free from metallic iron and from iron monoxide, and of magnetic fractions composed by metallic iron and iron monoxide; and low-intensity magnetic separators (35, 36 and 37) to reprocess the magnetic fractions with generation of concentrate with high metallic iron contents and a product with high concentration of iron monoxide.

A process and system having a primary crusher to reduce the fragments according to their granulometry; a magnetic separator to remove metallic fragments bigger than a determined granulometry; a rotary dryer to dry slag; an impact mill to disaggregate and fragment slag particles; a classifier for aero-classification and drag of fine and superfine particles; a cooler for cooling slag by means of heat exchange and removal of the fine and superfine particles that were not collected by the impact mill a vibrating sieve provided with two or more decks with screens of predetermined sizes; low-intensity magnetic separators, with generation of non-magnetic slag fractions free from metallic iron and from iron monoxide, and of magnetic fractions composed by metallic iron and iron monoxide; and low-intensity magnetic separators to reprocess the magnetic fractions with generation of concentrate with high metallic iron contents and a product with high concentration of iron monoxide.