High-alumina composite concretes and coatings based on modified phosphate binder suspensions

Coatings and materials based on aluminum phosphate suspensions are studied that have high strength in a raw state and are suitable for carrying out combined firing of a refractory and coating. An aluminum phosphate binder provides preparation of high physicomechanical properties in the firing temperature range. Use of traditional mixes with a protective aluminum phosphate coatings, and also ceramic concrete based on this binder provide increased material corrosion resistance, and consequently an increase in object operating life and period between repairs for metallurgical and glass melting units.     

Periclase concretes based on a silicate binder

OOO Gruppa Magnezit has developed a new generation of periclase cement-free concretes based on a MgO–SiO₂ binder with a service temperature from 1500 to 1700°C depending on filler composition. The technology assimilated makes it possible to prepare refractories of complex shape for lining elements of CBCM intermediate ladles and other units.     

Producing alumosilicate heat insulation components with ethyl silicate binder

The company has developed a technology for making alumosilicate heat insulating components (lightweight) with ethyl silicate binder. Industrial tests have been performed and regular production has been initiated. Translated from Novye Ogneupory, No. 12, pp. 19–21, December, 2008.     

Refractory concretes and coatings based on modified binder suspensions

The process of manufacturing protective coatings by means of deposition of aqueous suspensions is distinguished by the simplicity of the technological process and the low temperature at which it is realized. Phosphate-containing binders and concretes based on these types of binders increase the resistance of the particular material to corrosive media. Through their use it is possible to increase the service life of refractories.     

High-temperature creep in ceramics

Creep in ceramics is discussed as opposed to metals in the light of previous findings. Three aspects of the issue are singled out. They are the phenomenology of the process, that is, the kinetics of deformation (creep curves) and their dependence on temperature and load; the evolution of the process at the microscopic level and the role of some structural characteristics; and elementary deformation events largely determined by the type of chemical bonding and the structure of the unit cell. It is shown that crystalline inorganic dielectrics differ from metals not only in the underlying mechanisms of mass transfer, but also in the action of the mechanical stress gradient: in metals, mass transfer is mainly effected by shear, whereas in ceramics it is controlled by diffusion.     

Effect of binder content on the performance of alkali-activated slag concretes

This paper assesses the mechanical and durability performance of concretes produced using alkali silicate-activated ground granulated blast furnace slag as sole binder. Alkali-activated concretes are formulated with 300, 400 and 500 kg slag per m³ of fresh concrete, and their performance is compared with reference concretes produced using Portland cement (OPCC). Regardless of the binder content, the alkali-activated slag concretes (AASC) develop higher compressive strength than the comparable reference concretes. A higher binder content leads to increased strength in both AASC and OPCC at 28 days. However, at 90 days, the performance penalty for low binder content is more significant in the OPCC than AASC samples. Permeability, water sorption and carbonation resistance properties are also improved at higher binder contents. By controlling mix design parameters, it is possible to produce AASC with mechanical strength and durability comparable to conventional Portland cement concretes.     

Metal resistance of refractory concretes based on phosphate binders

Conclusions We studied the resistance of the fused magnesite, corundum, and quartzite-based materials produced using phosphate binders to molten aluminum and copper. It was established that the materials based on fused magnesite and corundum are most stable in molten aluminum and the materials based on fused magnesite have the maximum resistance to molten copper.Translated from Ogneupory, No. 8, pp. 17–18, August, 1987.     

Strength properties of chamotte concretes based on phosphate binders

Conclusions The authors have investigated the strength properties of chamotte concretes based on phosphate binders over a wide range.They have shown the dependence of the compressive strength of the concretes on the type of phosphate binder used, the heat treatment temperature of the concrete, and its test temperature. Maximal compressive strength is exhibited by concretes roasted at 1450°C.They have established a relation between the physicochemical transitions taking place in a phosphate binder during heating and the strength characteristics of the concrete.Simultaneous introduction of phosphate binder and clay to the extent of 10–20% into chamotte concretes increases their strength at 20°C and during heating.Translated from Ogneupory, No. 6, pp. 32–36, June, 1979.     

Thermostable alumina — Silica concretes based on chamotte — Quartz binder suspensions

Process techniques are proposed for separate addition of polydisperse filler fractions in the preparation of casting molding mixtures based on chamotte — quartz binder suspensions. The effect of the fractional composition of the filler in such mixtures on the physico- and thermomechanical properties of cementless concretes after drying and firing has been studied. A substantial increase in the thermal stability of concretes based on a chamotte — quartz binder suspension has been achieved by replacing fine (up to 2 mm) chamotte fillers in their composition with materials with a low temperature coefficient of linear expansion, such as SiC or cordierite. Translated from Ogneupory, No. 4, pp. 2–6, April, 1994.     

磷酸盐基胶粘剂的研究与应用

介绍了磷酸盐基胶粘剂的组成,讨论了磷酸盐基胶粘剂的耐高温性、低污染性、轻质性、粘接无破坏性等特点,论述了目前常用磷酸盐基胶粘剂的制备方法以及在复合材料、陶瓷材料、涂料和耐火材料方面的应用,并指出了磷酸盐基胶粘剂的研究发展方向。     

High-temperature creep in refractory ceramics. Porous materials

Results on high-temperature creep in porous ceramics and refractories obtained for model specimens are presented. The role of the shape, size, and number of pores and the effect of some manufacturing parameters (grain composition of the charge and compaction pressure) are discussed. It is established that the deformation rate is independent of the shape and size of the pores and is determined by the porosity and the degree of development of interparticle contacts.Translated from Ogneupory, No. 10, pp. 2–6, October, 1994.     

Heat-resistant thermally insulating concretes with phosphate and aluminate binders

This article describes heat-resistant thermally insulating concrete mixtures and products with phosphate and aluminate binders, their properties, and the main processes used to make them. The thermophysical properties required of thermal insulation are obtained together with an increase in its strength thanks to the production of denser but less heat-conducting concretes with fillers composed of aluminum microspheres.