Processes of Replacement by Melt at Interaction between Refractory Materials and Industrially Produced Melts

In a number of industries (ferrous and nonferrous metallurgy, glass-making and silicate-producing technologies), interaction between refractory materials with melts results in sequences of reaction zonation (reaction columns) that show all principal features of diffusion-controlled metasomatic zoning. However, in contrast to the latter, reaction melt is generated together with crystalline phases in the rear zones of the columns. This melt is neither mechanically displaced melt that affects the refractory materials, nor produced by melting. The process generating this melt is most adequately defined as replacement by melt. The principal characteristics of the zoning are discussed below with reference to the corrosion of chromite–periclase refractory materials with melted slag in nickel-producing metallurgy. Similarities between the relations observed under different conditions and in different systems and the evolutionary dynamics of the process, specifics of melt generation and changes in its composition in the zones are demonstrated below with the use of data on other technologies and their experimental modeling. The mechanism of melt replacement is applicable to describing natural reaction processes of magma interaction with host rocks (magmatic replacement), with the following unobvious implications. (1) It is reasonable to expect that the minerals of the rocks should host melt inclusions. (2) It is reasonable to expect that certain minerals should be found in two distinct populations: (i) those in equilibrium with melt in the reaction column and (ii) those crystallizing from the cooling melt. (3) Two or more zones of the column can consist of the same minerals, but their proportions should be different. (4) Plastic deformations in the rear zones of the column (magmatic replacement) should be associated with brittle ones in the pristine host rocks and frontal (metasomatic) zones. (5) In contrast to the rocks of metasomatic columns, the material of magmatic-replacement zones can flow through fractures cutting across the host metasomatic rocks and thereby intersect the outer metasomatic zones.