The results of a study of the possibility of bulk dyeing of ceramic brick by incorporating manganese and iron ore and metallic slags and sludges from electroplating plants in the pastes are reported. It was found that low-melting clays should first be bleached with chalk or fireclay or kaolin impregnated with solutions of transition metal salts in order to attain a broad color scale for the articles. Using natural raw materials and soluble salts of 3d elements significantly expands the raw-materials base, reduces the cost of the ceramic articles by replacing expensive materials, and combines synthesis of pigments and firing of the articles.

The results of an investigation of the possibility of synthesizing pigments with corundum -spinel structure are presented, and the methods for directed regulation of structure-and phase-formation processes so as to produce pigments with the highest physical -chemical indicators are developed. The relation between the temperature -time parameters of synthesis and the content of modifying oxides and mineralizers with the type and amount of color carrying phases, which give saturated color and a range of pigments colors, are determined.At the present time ceramic pigments are synthesized on the basis of crystallized compounds which can withstand high temperatures, the dissolving action of glazes and fluxes, and corrosive media. Spinel of the first and second types, corundum, zircon, perovskite, and others, are used as the crystalline acceptor-lattices. When transition metal ions (Cr, Fe, Ni, Co, Mn, and others) are incorporated into the crystal lattice of these minerals, the crystal acquires coloration which is due to the absorption of light because of either d -d transitions of electrons or charge transfer. The ions named above are introduced into the crystal lattice by means of solid-phase reactions, which occur at temperatures 1200 -1300°C in the presence of mineralizers (H 3 BO 3 , NaF, and CaF 2 ).Isomorphic solid solutions with different compositions are formed when during the synthesis process transitionmetal oxides partially or completely substitute for the oxides in the crystalline acceptor-lattices.The purpose of the present work is to develop methods of directed regulation of the structure and phase formation processes during the synthesis of pigments with corundumspinel structure which possess a high light reflection coefficient, and high thermal and chemical stability and to determine how the temperature -time parameters of synthesis and the content of the trace modifier-oxide additives and the mineralizers are related with the amount of the color-carrying phases formed, which make it possible to obtain pigments with saturated color and a wide color range.Technical grade alumina (Al 2 O 3 ) was used as the initial component for synthesizing pigments. The following additional components were introduced into the pastes: mineralizer (H 3 BO 3 ), modifiers (ZnO, CaO, CdO, SrO), and chromophore oxides (Cr 2 O 3 , Fe 2 O 3 ). The powders of the initial components were carefully milled and mixed together. The prepared samples were calcined in an electric furnace at temperature 1100, 1150, and 1200°C with a holding period of 1 h at the maximum temperature.It was determined that as a result of heat treatment of technical-grade alumina at 1200°C in the presence of a modifier aluminum oxide transforms from the g into the b form and then into a-Al 2 O 3 .Mineralizers have a large effect on the crystal lattice of the synthesized material as well on the color of pigments. The effect of the mineralizers is to form a liquid phase, which loosens the crystal lattice, putting it into an active state. It is known [1] that ...

Synthesis of ceramic pigments with equimolecular ratios of oxides (Nd 2 O 3 : P 2 O 5 , Nd 2 O 3 : ZrO 2 , Nd 2 O 3 : TiO 2 ) was investigated. It was shown that these oxide ratios allow obtaining pigments of different palettes suitable for coloring glazes.

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The results of a study of the possibility of bulk coloring of tile pastes by impregnating the clay with solution s of salts of 3d-elements (Ni, Co, Cr, Fe), which allows obtaining pigments of mullite-like structure with high chromophoric indexes based on energy-saving technology, are reported. The use of natural raw material and soluble salts of 3d-elements makes it possible to significantly expand the raw-material base, reduce the cost of the manufactured product by replacing expensive materials and combining synthesis of pigments and firing of the articles. Different natural silicates, including laminar silicates such as refractory clays, are used in synthesis of ceramic pigments [1]. Kaolinite Al 2 O 3 × 2SiO 2 × 2H 2 O is the basic rockforming mineral. The crystal lattice of kaolinite, a mineral of lamellar structure, is of the open packing type, consisting of two layers: octahedral and tetrahedral. The first consists of silicon-oxygen tetrahedrons [SiO 4 ] 4-and the second consists of aluminum cations. Hydroxyl ions [OH] -are positioned on one side of the packing. Tetrahedral layers are shifted by 1/3 with respect to the octahedral layers.LT-1 clay from the Latnensk deposit was used as the initial feedstock. This clay is refractory, finely disperse, hightemperature sintering, and contains no more than 2.5% coloring oxides (Fe 2 O 3 + TiO 2 ). 2 In selecting the basic raw materials, we were guided by the properties of the clays, which allow isomorphic substitution of Al 3+ ions of transition 3d-elements (Fe 3+ , Cr 3+ , Co 2+ , Ni 2+ , Mn 2+ ). The good wettability of the clays makes it possible to rapidly impregnate the clays with solutions of salts of the coloring ions of transition 3d-elements. Preliminary impregnation of the clays allows combining firing of the ceramic ware and synthesizing pigments, which reduces heat and power consumption in production of ceramic materials.We investigated the features of coloring of ceramic materials with synthetic pigments and impregnation with the salts of transition d-elements and the possibility of incorporating coloring ions in the crystal structure of a natural mineralrefractory clay, without additional charge adjustment. Co 2+ , Cr 3+ , Fe 3+ , and Ni 2+ ions were used as chromophores [2,3].The pigment paste colored with the solutions of transition metal salts was obtained as follows. LT-1 clay was dried, ground, sieved, then impregnated with 35% solutions of K 2 Cr 2 O 7 , Fe(NO 3 ) 3 × 9H 2 O, Ni(NO 3 ) 2 × 6H 2 O, and Co(NO 3 ) 2 × 7H 2 O in the amount of 5, 10, and 15% in terms of oxides. A solution of acetic acid (3 ml of 9% CH 3 COOH per 100 ml of salt solution) was added to increase the porosity of the clay and ensure better impregnation. Hot solutions (80 ± 10°C) were used for better dissolution of the salts and more careful coloring of the clay raw material. The mineralizer was 5% borax H 3 BO 3 . For comparing the chromophoric properties of the salts and oxides of the same metals, LT-1 clay was also colored with oxides -CoO, Cr 2 O 3 , Fe 2 O 3 , and Ni...