PRODUCTION OF IRON AND STEEL USING HIGH PHOSPHORUS ORE AS RAW MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide an iron and steel producing method, by which dephosphorizing treatment can efficiently be executed to molten iron obtd. by using high phosphorus ore as a raw material and the adding quantity of flux and the produced quantity of slag, etc., can be reduced as much as possible. SOLUTION: In the dephosphorizing method of the molten iron having high phosphorus concn., it is extremely effective that the silicon concn. in the molten iron is beforehand reduced to the achievement of high dephosphorizing efficiency and the lowering of the produced slag quantity. This method consists of at least a process for charging the iron ore having =0.06 wt.% phosphorus concn. as a part or the whole of the iron source into a blast furnace, a process for obtaining molten iron having =0.20 wt.% silicon concn. by executing a desiliconizing treatment at iron-tapping from the blast furnace or after iron- tapping from the blast furnace, a process for executing the dephosphorizing treatment to the low silicon molten iron undergone the above process and a process for executing a decarburizing treatment to the molten iron undergone the dephosphorizing treatment process.