Development of research on the physico-chemical properties of oxide and metal melts

The paper considers the historical development of scientific views on the structure of oxide and metal melts. The authors, using the research of the Ural Scientific School and their own works as examples, examine the evolution of approaches based on the polymer (ionic) theory of oxide melts and the cluster theory of liquid metals. The possibility of using a polymer model to determine the boundary of slag transition from a homogeneous state to a heterogeneous one and conditions for the formation of a homogeneous slag with maximum refining properties is shown. Al 2 O 3 can exhibit both basic and acidic properties. It was found that with Al 2 O 3 content of up to 16 % in oxide melts corresponding to the slags formed in ladle furnace unit, alumina exhibits basic properties, and when its content exceeds more than 16 %, it begins to exhibit acidic properties. Additional information on activities of the oxide melt components allows us to determine the parameters of the slag with the best properties for non-metallic inclusions absorption. Metal melt is characterized by a “critical” temperature at which the melt during heating transitions from hereditary cluster-type disequilibrium to a state of thermodynamic equilibrium, i.e., the melt “homogenizes”. Nonequilibrium melts temporarily retain elements of the structures of the initial phases. Overheating of the metal above the “critical” temperature during thermal-time treatment makes it possible to improve and stabilize the quality of products. Modification of the melt leads to a significant decrease in the amount of necessary overheating and acceleration of the homogeneous melt formation. Fundamental studies of the properties and structure of metal liquids showed the development of a new applied direction under the general name “thermal-time treatment”.