The benefication of steel contained powders in steel making slags and the manufacturing process of a substitute for sintered ores

摘要

PURPOSE: A method for benefication treating iron fine in steelmaking slag and manufacturing sintered ore substitute is provided to produce scrap substitute and sintered ore substitute by reprocessing iron fine having grain diameter of 8 mm or less magnetically adhered to a magnetic separator during recovering and treating of steelmaking slag and iron powder. CONSTITUTION: The method comprises a pretreatment step of sorting the iron fine into iron fine having grain diameter of 3 to 8 mm and iron fine having grain diameter of less than 3 mm by sieving the crushed iron fine with a mesh screen having a sieve size of 3 mm after collecting and crushing iron fine having grain diameter of 8 mm or less and containing 50 to 75% of the total iron powder content magnetically adhered to a magnetic separator during the process of recovering and treating steelmaking slag and iron powder; manufacturing the iron fine having grain diameter of 3 to 8 mm magnetically adhered to the magnetic separator into a strip fragment shaped scrap substitute containing 95 to 99% of the total iron powder content by sieving and magnetically separating the recrushed iron fine after recrushing the iron fine having grain diameter of 3 to 8 mm sorted in the pretreatment step; and a step of recrushing and sieving the iron fine having grain diameter of less than 3 mm sorted in the pretreatment step, magnetically separating the sorted iron fine having grain diameter of 1 to 3 mm using a magnet having the Gauss range of 1,000 to 4,000 and the sorted iron fine having grain diameter of less than 1 mm using a magnet having the Gauss range of 500 to 2,000, adding a binder to the iron fine magnetically adhered to the magnet, and manufacturing a green compact obtained by briquetting the mixture of the iron fine and binder into sintered ore substitute containing 75% or more of the total iron powder content.