Development of Dephosphorization Process of Hot Metal by Simultaneous Injection of Gaseous Oxygen and Iron Oxide Flux with Single-hole Lance

Abstract

A new process for dephosphorization of molten pig iron was developed, which is characterized by a single-hole lance used to inject gaseous oxygen with powder flux containing iron oxide.
Experiments with a 200-ton torpedo car were carried out. The ratio of gaseous oxygen to total oxidizing component in gas and flux was changed from 0% to 40%.
The suppression of temperature drop per one percent of gaseous oxygen was 1.44°C/%. The oxygen utilization efficiency for dephosphorization was not affected with the gaseous oxygen ratio in the range from 0% to 25%. The lance can be used more than 3 heats when the gaseous oxygen ratio was less than 25%, which is sufficient for industrial use.
The lance wear rate depended significantly on the ratio of the input heat by molten metal around lance to the output heat by flux and gas in the lance pipe. It is suggested that a stable and uniform flux flow in the lance pipe is effective to decrease the lance wear rate.