The creation of new porous permeable ceramic materials with a different microstructure and a controlled pore size from nano-to microsize that have properties markedly surpassing those of traditional materials used in industry, and organization of the production of various objects made from them will make it possible to obtain a considerable economic and ecological effect. Specific examples are provided for the use of objects made of porous permeable ceramics developed in ZAO NTTs Bakor in various branches of industry.The problem of doubling the internal gross product is closely connected with resolving problems of the ecology and economics of natural non-renewable energy resources. One of the main ways for resolving the problem may be, and should become, creation of new materials, organization of the production of various objects made from them and extensive use of these objects in various branches of industry instead of objects made from morally aging traditionally used materials [1].Over fifteen years the scientific and technical center Bakor has been occupied in developing and producing special forms of advanced ceramic and refractory materials. One of the priority areas in this activity is creation and production of porous permeable ceramic materials with pores controlled from nano-to microsizes for the manufacture of filtering elements used in filtration units of various types [2]. As the practice of using objects made of porous permeable materials has shown, this material in the present stage of development of the technology manifests itself in the most important branches of industry for the national economy.Filtering elements made from porous permeable ceramics in ZAO NTTs Bakor of find extensive use in the mining and metallurgical industry for filtering solutions of electrolytes and dewatering flotation concentrates before pyrometallurgy.More than ten years ago in the mining and metallurgical industry commenced extensive use for candle-shaped filtering units intended for filtering solutions of the electrolytes of copper, nickel, cobalt, in which on a industrial scale filtering elements made from porous permeable ceramic (Fig. 1) were used for the first time.Before this, filtering presses of the open type were used in order to filter electrolyte solutions. The consumption of filtering cloth (belting) reached 120 thousand m 2 /year, and the wood for making frames and plates reached 1800 m 3 . As the practice of using candle-shaped filtering units has shown, they are simple for servicing and they their specific productivity is greater by a factor of ten than for filter presses of the open type (Table 1).

No abstract

The effects have been examined of adding nanocrystalline zirconium dioxide powder stabilized by yttrium oxide on the production and properties of a composite material based on zircon. It is found that the zirconium dioxide particles at the boundaries of the zircon grains slow the consolidation of the zircon matrix in sintering and zircon grain growth.Keywords: nanocrystalline zirconium dioxide, ceramic composite material.The high prices are a factor retarding the general introduction of ceramic materials in various branches of industry. The cost of a ceramic can be substantially reduced by the direct employment of mineral raw materials.Zircon is zirconium orthosilicate ZrSiO 4 and is used as a natural mineral raw material in the refractories industry, casting, and generally in the production of building materials and drainage fitments. About 10% of zircon is processed to give zirconium dioxide [1]. A ceramic based on zircon has a comparatively low coefficient of linear expansion and moderate thermal conductivity. The thermal shock resistance of zircon exceeds that of corundum, zirconium dioxide, and mullite, and also it has high chemical resistance in acid media [2].Ceramic materials have a wide range of properties and on many parameters are better than metals and polymers, but they have a major shortcoming: low level of failure viscosity, which is due to the ionic-covalent type of atomic bonds. A method of increasing the resistance to crack growth in ceramic materials is to produce composite structures. There are two most effective lines: producing a transformation-hardened ceramic with dispersed inclusions of metastable ceramic phase or a ceramic strengthened by fibers. Particles of metastable tetragonal zirconium dioxide are used to strengthen various ceramic matrices. The most effective results have been obtained on adding them to a corundum matrix [3,4]. Added nanodimensional powders favor the consolidation of the ceramic and reduce the sintering temperature [5].The present concerns the effect of added ZrO 2 nanopowder stabilized by Y 2 O 3 on the making of a composite based on ZrSiO 4 . EXPERIMENTALWe used a zircon concentrate termed Zircon standard grade (Possen Erzconter), for which the certificate states the following wt.% composition: ZrO 2 + HfO 2 66.0, SiO 2 (total amount) 32.7, SiO 2 (free) 0.26, Fe 2 O 3 0.2, TiO 2 0.25, Al 2 O 3 0.18, CaO 0.1, MgO 0.03, Cr 2 O 3 0.002, P 2 O 5 0.14; the zirconium dioxide stabilized by 5 wt.% yttrium oxide was added in the form of a powder made by the reaction between a solution containing the chlorides of these metals and an aqueous solution of ammonia (Start Scientific Production Business Corporation, Perm, Russia) [6].The powders were ground and mixed in a SAND planetary mill at a speed of 160 rpm in the dry or in 0.5% aqueous solution of polyvinyl alcohol (PVA); the ratio of the masses of powder, grinding bodies, and liquid were 1:2:1. The dried and ground powders were used in making specimens by cold uniaxial pressing (CP) and cold isostatic pressing (CIP). The...

A reduction in manufacture expenditure for a production unit, and also preparation of metals and alloys in pure and ultra-pure form may be achieved using newly created filtering elements made of porous permeable ceramic materials with a pore size controlled from "micro" to "nano". Methodology is presented for creating filtering elements made of porous permeable ceramic based on a concentrate of disthene-sillimanite for candle-shaped filtering elements.Keywords: porous permeable ceramic material, filtering elements, candle-shaped filtering equipment, disthene-sillimanite concentrate (DSC).Analysis of trends in the development of inorganic materials science indicate that in the next 15 -20 years the main forms of structural materials of mass demand will remain ferrous and nonferrous metals, and also alloys base on them. Therefore questions of reducing expenditure for manufacturing production units and obtaining metals and alloys in pure and ultrapure form will be very important. Use of filtering elements created using innovative technology for porous permeable ceramic with a regular pore size from "micro" to "nano" will make it possible to resolve this problem effectively with minimum expenditure [1].In order to prepare pure nickel, zinc and cobalt solutions for electrolysis it is necessary to have multistage filtration in order to remove extraneous impurities. In enterprises of the mining and metallurgical industry for these purposes filter presses of the open type have been used with manual unloading of the cake (deposit). Solutions have been filtered through cotton belting mounted on wooden frames and plates. According to data of the OAO Severonikel' Combine the annual consumption of belting reached 120 thousand m 2 , and in order to manufacture frames and plates about 1800 m 3 of first class wood was consumed. It is impossible to mechanize and automate filtration in these units. The specific productivity of filters was low and was 0.12 -0.25 m 3 /(m 2 × h) with an excess pressure of 0.10 -0.15 MPa.In the 1980s mining and metallurgical enterprises started to put into production candle-shaped filtering units produced in Germany with filtering elements made of porous permeable ceramic in the form of hollow cylinders. The cake was removed from the surface filtering elements in these filtering units as a result of feeding compressed air to the inner cavity of the filtering element that made it possible to alternate filtration. The productivity of candle-shaped filtering units is 1.30 -1.79 m 3 /(m 2 × h) with an excess pressure of 0.45 -0.48 MPa, i.e. significantly higher than previously used filter presses. During operation candle-shaped filtering units have demonstrated high efficiency and operating capacity. In the stage of introducing and assimilating filtering element units they were supplied from Germany. Subsequently production of filtering elements (based on fractionated chamotte) was assimilated in Keramkombinat, Slavyansk, Ukraine [2]. During operation these filtering elements revealed their main disadvant...

Results are presented on the corrosion resistance of chromium-bearing refractories of granular structure acted on by corrosive molten slags, metals, and glasses. It is possible to recommend these refractories to customers for particular conditions of use. Chromium-bearing refractories increase the working lives of furnaces considerably.Innovative technologies are being widely introduced in ferrous and nonferrous metallurgy, the chemical industry, the petroleum industry, the building industry, and other such, which is related to a considerable extent to intensify hightemperature processes in furnaces. This greatly increases the importance of refractory materials that must provide prolonged operation [1].About two-thirds of refractory materials are damaged by chemical interaction with corrosive media, so particular attention attaches to research to improve existing refractory materials and produce new ones for use at high temperatures subject to the action of corrosive liquids: slags, fluxes, glasses, glazes, and enamels [2].The Bakor Company has for more than 15 years developed and produced refractory materials and components providing prolonged service in important lining elements [3]. The materials most resistant to various corrosive media are highly refractory ceramic ones containing chromium oxide [4,5]. Research at the company has provided a technology for making various chromium-bearing refractory materials of granular structure resistant to corrosive melts and of thermal resistance elevated by comparison with dense materials [6]. Figure 1 shows the scheme for producing them. Table 1 gives the physicochemical properties of these chromium-bearing refractories.The research included the reactions of corrosive melts of various types with the chromium-bearing refractories of granular structure developed by the company. The crucible method [7] was applied to the corrosion resistance. This method is a static one for testing materials for corrosion resistance in corrosive liquids, which quite fully reproduces the corrosion conditions for refractory materials in furnaces. The crucible method also gives a clear idea of the corrosion resistance at the level of the liquid under conditions of three-phase separation.The test specimens were made as cylinders (diameter and height 60 mm) or as cubes of edge 60 mm with recesses of diameter 22 mm and depth 35 -40 mm. The crucibles contain materials for making liquids. The heat treatment was in a muffle furnace with chromite-lanthanum heaters at temperatures corresponding to the actual working conditions. After test, the specimens were sectioned parallel to the axis of the hole and photographed. To examine the damage mechanisms and phase transformations we performed micro-