The invention pertaining to the field of convertor
steelmaking technology provides a technique of converter
smelting by using a dephosphorization agent. In a same convertor, dephosphorization is performed by using a CaO-base ephosphorization agent containing a few CaCl2 under favorable
thermodynamics and combined-blowing dynamics conditions such as low temperature at the prior period, high content of
iron oxide and the like, the prior period, desilication and dephosphorization slags of 50-70% are poured away in the molten iron preprocessing process, in the later period,
decarburization process is performed and
decarburization slag is formed and is then utilized as dephosphorization
slag of the lower converter. According to the
smelting technology, CaCl2 is added to the CaO-base ephosphorization agent to accelerate the burn-
off rate of CaO by using the eutectic point character of CaCl2 and CaO binary
system, the utilization ratio of
lime is also improved, the utilizing of
decarburization slag not only fully utilizes the
physics heat brought by the decarburization slag, but also provides high content
iron oxide for the dephosphorization of the prior period and accelerates the dephosphorization reaction.The invention has advantages of low cost of investment, shortened
smelting period, carbon content of 0.4% at the end point of smelting,
phosphorus content capable of being reduced to 0.006% and dephosphorization ratio up to 95.5%.