PURPOSE: To obtain a premolten flux having a remarkable dephosphorizing effect by melting a mixture consisting of quick lime, calcium chloride and iron oxide by heating, rapidly cooling the melt at a specified temp. dropping speed, and pulverizing the cooled product.

CONSTITUTION: A mixture consisting of required amounts of quick lime, calcium chloride and iron oxide or further contg. silicon dioxide and aluminum oxide is melted by heating at ≥1,400°C. The melt is rapidly cooled so that the temp. is dropped by ≥600°C within 15sec. The cooled product may be pulverized. By this method a premolten flux for dephosphorizing molten iron is obtd.