Abstract

This invention is directed to a method and apparatus for controlling the injection of flux into a steelmaking vessel as a function of the differential pressure between the flux containing tank and the main conduit which supplies oxygen to the tuyeres of the steelmaking vessel in the Q-BOP process. A branch conduit diverts a portion of the oxygen stream from the main conduit and flux from a pressurized flux-containing tank is injected into this secondary stream which secondary stream is then recombined with the main stream. The apparatus measures the pressure differential between the main conduit and the flux tank and also compares the actual flux injection rate with a preset reference rate; a voltage signal representing the measured pressure differential and one representing the comparison between the actual and reference rates are compared with each other to provide a signal for controlling oxygen supplied to and vented from the pressure tank to vary the differential pressure between the primary conduit and the tank and thereby control the rate of flux injection into the secondary conduit as a function of this pressure differential.The apparatus also measures the amount of flux injected into the secondary conduit and shuts off the supply when the measured amount equals a preset desired amount.