A raw material for steel-making. When the iron produced by the blast furnace was transported to the steel mill by the torpeds, fluorspar was added as a flux to prevent the slag from hardening and reducing the capacity of the torpeds. This helped increase the flow of iron so that the slag was easier to remove after the torpeds left the mill. In addition, during the process of desulfuration, dephosphorization, and removing the slag from the ladle furnace, a huge amount of limestone is added and the fluorspar is used as a flux to increase the process and the flow of the slag. (Donated by CSC)