Abstract: A process for adjusting the composition of a liquid metal, such as steel, is provided wherein liquid metal is sucked up from a start receptacle into a reactor which is at a reduced pressure with respect to the start receptacle. First, the liquid metal is made to flow inside the reactor under conditions close to plug flow where it undergoes a metallurgical treatment. Next, after the liquid metal has been conveyed through the reactor it is completely discharged into a finish receptacle which is also at a reduced pressure with respect to the reactor. To insure thorough mixing, the reactor is divided into a plurality of cells, each of which has its own independent gas injector for agitating the liquid metal therein.