Method for smelting low-phosphorous molten steel by utilizing semisteel

The invention belongs to the metallurgical field, particularly relating to a method for smelting low-phosphorous molten steel by utilizing semisteel. The technical problem solved by the invention is to lower the phosphorus content of the final molten steel so as to be beneficial for producing the low phosphorus steel on the premise of ensuring converter decarburization effect. The technical scheme for solving the technical problem in the invention is to provide the method for smelting the low-phosphorous molten steel by utilizing the semisteel. The method comprises the following steps: mixing the semisteel subjected to desulfuration and vanadium extraction into a converter; adding the first batch of steelmaking slagging agent; converting for 4-6 minutes in the converter; slagging; and adding the second batch of slagging agent for converting. By adopting the method of the invention, the final molten steel can be obtained, wherein, the phosphorus content is less than or equal to 0.006%; and the dephosphorization rate of the converter achieves over 92.5%. On the premise of not influencing steelmaking dephosphorization and decarburization tasks, the method of the invention lowers the phosphorus content of the final molten steel, and provides important technical support for producing the low phosphorus steel.