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).
The corrosion resistance of refractories to frit melts applied at the Velor Ñompany (city of Orel) are investigated. Based on the results of the study, it is proposed to replace the refractory MKS, which is currently used in furnaces for melting frit glazes, by the refractory material KMTs that is more resistant to frit melts.The quality of product, the campaign duration, and the efficiency of glass-melting tank furnaces to a large extent depend on the type of refractories used in their brickwork. High-quality refractories significantly decrease the quantity of defects (nonmelted frit, presence of inclusions, etc.) and make it possible to melt frit at a higher temperature, which, in turn, as an essential prerequisite for raising the furnace efficiency. Even though the cost of refractories in this case may grow perceptibly, the improved quality of refractories eventually yield more significant savings.One of the most important properties of refractory materials used to line furnaces for melting frit glazes is their corrosion resistance to aggressive melts. Corrosion is a complex phenomenon depending on the physicochemical, structural, and texture specifics of refractories, on the technological and design parameters of the furnace, and on the melt composition [1]. Therefore, the choice of refractories to be used as lining in furnaces for melting frit glazes can be made only based on experiments determining corrosion resistance of refractories in frit melts.Our study gives the results of analyzing corrosion resistance of refractories in frit melts used at the Velor Company (city of Orel). Certain physicochemical properties of frits are presented in Table 1.Refractory brick MKS-72 (GOST 24704-94) used at the Velor company for furnace lining soon becomes destroyed under the effect of aggressive melt. The service of the furnace between repairs does not exceed one year.It is known that the higher is the content of zirconium dioxide in refractories, the higher their corrosion resistance. As alternatives to refractory MKS-72, we have chosen refractories produced by the Bakor Scientific Technical Center according to TU
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...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.