PURPOSE: To effectively utilize the slag of reducing period of electric furnace for recycling to the aggregate and flux of electric furnace refining time, by carrying out cooling, magnetic separation, sieving after cooling solidified slag slowly and powdering it.

CONSTITUTION: Solidified slag is heaped up in the slag pan on the grate bar 1 and is cooled slowly and powdered by sprinkling water or sending cold air. Next, the slag is dropped on the hopper 2 and is cooled by the water cooling apparatus 3 and air and then, is transferred to the chain conveyor 4. The slag is cooled at about 100°C or less by the cooling apparatus 3 in the hopper of exit side of the conveyor 4 moreover and is transferred to the belt conveyor 5. The blocks or grains of iron 7 are recovered by using the magnetic separator 6 at dropping opening of the conveyor 5. Powdered slag is sieved putting in vibrating sieve and the coarse grain slag 9 on the sieve are recovered as coarse aggregate etc. and powdered slag under the sieve is taken out in the container 10 etc. after storing in the cyclone 8 and is recycled as the resources of pellet etc.