Black ceramic pigments based on open-hearth slag are obtained. The possibility and sequence of physicalchemical processes occurring during kilning of pigment mixes are evaluated and the nature of the color-carrying phases in the products of their heat-treatment is determined. The relation between the crystal-phase composition and the optical indicators of the slag-containing pigments is studied. It is shown that such pigments are promising for coloring various glazes.

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A probable order of the formation of structural units in glasses of the Na systems as a function of the alkali oxide content is analyzed in terms of the strengths of the cation-oxygen bonds of the glass components. The principle of the structure formation in silicate glasses is proposed. It is demonstrated that the chemical composition of glasses can be used to predict the existence of structural groups favoring the crystallization of titanium-containing phases in the glass and, consequently, the influence of the composition on the opacity of enamel coatings.

The existing hypotheses on the structure of alkali borate glass were comprehensively analyzed. Their imperfection in explaining the dependences of the properties of the glasses on their composition was noted. Alternative schemes of structural borate complexes which more convincingly explain the characteristics of the change in the properties of this glass are proposed.The questions concerning the study of the structure of any substances are always pressing, since their solution will allow more accurately predetermining the properties of the synthetic materials being developed. The lack of direct methods of investigating the structure of amorphous substances unfortunately makes it difficult to solve problems on predicting the properties of these materials as a function of a change in their chemical composition. The use of methods of investigating the structure of crystalline to vitreous substances does not give unambiguous answers but on the contrary, many other difficult-to-resolve questions arise in analyzing the data obtained.For example, according to the data from many researchers, there is no break on the curve of the change in the proportion of four-coordinated boron ions as a function of the alkali oxide content in borate glasses (Fig. 1) in the region of an approximately 16% molar content of these oxides. At the same time, in determining the CLTE of these glasses in the indicated region of concentrations of Na 2 O, a sharp change in their values is observed [2] (Fig. 2). These events in alkali borate glasses are attributed to a change in their structure, more precisely, a change in the coordination of the boron ion with respect to oxygen. The impossibility of solving such problems with instrumental methods makes it necessary to use the methods widely used in humanitarian areas of science, where a multitude of versions of interpretations or hypotheses is proposed, and only those that most accurately explain the observed events or processes are selected. We propose using this approach in examining the structure of different glasses, namely, alkali borate glasses.

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