The influence of the complex additions SB-FF + STPP, S-3 + STPP, reotan + STPP on ceramic slip mobility is examined. The action of these complexes on the physical -chemical properties of ceramic samples after kilning is studied. It is found that the complex addition SB-FF + STPP makes it possible to increase ceramic slip mobility and mass build-up rate as compared with the additions based on S-3 and reotan as well as to improve the operating properties of finished articles.

The influence of complex additives on the critical structure-forming concentration of kaolin suspensions is studied. A complex consisting of the oxyphenofurfural oligomer SB-FF and sodium tripolyphosphate, which can be used as a fluidizing additive for kaolin suspensions, is most effective at low concentrations.Slips with minimum moisture content and adequate mobility are obtained by introducing fluidizing additives. Complex additives containing conventional electrolytes are promising: water glass and soda as well as sodium tripolyphosphate (TPP), oxyphenolfurfural oligomers SB-5 and SB-FF, and the superplasticizer S-3 [1, 2].The present work continues investigations in this direction. The concentrations and optimal ratios of SB-FF (product of the simultaneous condensation of phloroglucine and furfural) and TPP for suspensions of kaolin from the Glukhovetskoe deposit were found. For comparison, the following complexes were used: S-3 + TPP, SB-5 + TPP, and reotan + TPP. The initial suspensions were prepared with water-solid ratio 0.6, i.e., close to the critical concentration of structure formation or optimal moisture content. The effect of the concentration of complex additives on the rheological parameters of a kaolin suspension were investigated with a Rheotest-2 flowmeter. The rheological curves were used to determine the maximum dynamical shearing stress t 0 and the plastic viscosity h pl of a kaolin suspension. The dependence of the values of t 0 on the concentration of complex additives is presented in Fig. 1.When complex additives are introduced, the maximum dynamical shear stress, characterizing the strength of coagulation structures, decreases substantially. The most effective complexes at low concentrations are SB-FF and TPP. Thus, the introduction of 0.2% (SB-FF + TPP) decreases t 0 from 224 to 47 Pa, and complexes containing the oligomers SB-5, S-3, and reotan decrease t 0 to 61, 87, and 150 Pa, respectively.Previous investigations have shown that for a certain ratio of a dispersed phase and a dispersion medium in suspensions a sharp change is observed in the physical and chemical parameters of the system, characterizing a transition of the system from freely dispersed to structured [3,4]. Attraction forces between particles in the system start to predominate over the repulsion forces, and coagulation spatial structures where particles of the dispersed phase are coupled via thin residual interlayers of fluid are formed. The concentration of the dispersed phase at which such a transition is observed is called the critical structure formation concentration (CSC). An identical concept is used in ceramics technology -the optimal moisture content.The influence of complex additives on the critical structure formation concentration of kaolin suspensions was investigated in this work. The value of t 0 was used as an example characterizing the concept of structure formation. Kaolin

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The results of investigations of the effect of a complex additive containing sodium tripolyphosphate and resorcinol furfural oligomer on the wetting of solid surfaces are presented. It is shown that the wetting energy of an aluminum plate by solutions with a complex additive is much higher than the total energy of wetting by solutions containing separate components of a complex. The complex additive studied increases the wetting of an Al 2 O 3 surface, which decreases the free surface energy at the solid -solution interface.The production of modern construction articles is based on the preparation of high-quality initial material. One quality indicator for initial suspensions (ceramic slips and others) is their aggregative stability, i.e., conservation of the dispersity of the particles. Aggregative stability requires a stabilizer and good wetting of the surface of the particles of the disperse phase of the dispersion medium, since this allows an elastic solvation shell preventing particles from coagulating to form on the particle surfaces.Different additives are used as stabilizers. Our investigations [1 -5] as well as existing publications [6 -8] show that for many complex mineral suspensions, which ceramic slips and clay suspensions are, it is more effective to use complex stabilizing additives containing several components. This makes it possible to expand the range of possibilities for purposeful control of the properties of mineral suspensions and the properties of articles based on them.The angle of contact usually serves as a measure of wetting. The magnitude of this angle depends only on the nature of the substances participating in wetting, i.e., on the surface tension at the corresponding phase interfaces. One problematic question is the determination of wetting of powdered materials, for which the direct measurement of the contact angle presents significant difficulties. For this reason, model systems comprising the compounds SiO 2 and Al 2 O 3 were chosen for the present investigations. These compounds as well as the products of their interaction form the bulk of the minerals and rocks which comprise the initial materials for ceramic materials and articles. The investigation of the properties of mineral suspensions based on the chosen compounds is of theoretical and practical interest.We studied the wetting energy of solid surfaces wet by a solution containing a complex modifying additive making it possible to regulate the rheological properties of kaolin suspensions. The components of this additive are sodium tripolyphosphate (STPP) and resorcinol furfural oligomer SB-RF [3].Investigations to determine the wetting energy on different surfaces showed that the wetting energy of Al 2 O 3 plates wetted by solutions with a complex additive is much higher than the total wetting energy of an Al 2 O 3 surface wetted by solutions of SB-RF and STPP separately (Fig. 1). That is to say, the phenomenon of synergism is observed: the action of separate components is intensified when they are introduced together.S...

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