Creep of aluminosilicate refractories

Conclusions Investigations were made of the creep of industrial aluminosilicate refractories of various types, differing as regards the original materials, phase composition, the properties of the glass phase, and the structure. The results of the investigations characterize the plastic properties of materials in a fairly broad range of temperatures and stresses.Translated from Ogneupory, No. 7, pp. 39–43, July, 1969.     

Wettability of aluminosilicate refractories with molten steel

Conclusions An increase in the Al₂O₃ content of the base causes the wetting angle of steel 10kp to increase with an increase in the temperature from 1490 to 1620°C.Chromium-nickel steel wets refractories to a greater degree than rimmed steel. In this case the wetting angle is largest on mullite-corundum refractories containing 75–78% Al₂O₃.The introduction of small amounts of modifying additives in the form of MgO and Cr₂O₃+ ZrSiO₄ into mullite-corundum and corundum refractories causes the wetting angle to increase by 7–10° and helps to increase the resistance of the refractory materials to the action of rimmed steel.Translated from Ogneupory, No. 4, pp. 53–56, April, 1978.     

The wear of magnesia refractories in electric furnaces for melting cast iron

Conclusions The wear of magnesia refractories, i. e., magnesite, perictase — spinel, and magnesite — chromite bricks and magnesite — phosphate mortar, in the walls of electric furnaces for melting cast iron is the result of the solution predominantly of the periclase crystals and to a lesser extent of the spinel in the lowbasicity ferrosilicate slag melt. Brick of the PShS type proved to be the most durable refractory. The use of high-alumina brick in the roof of the furnaces accelerates the wear of the magnesia bricks in the walls.To increase the durability of the lining of these furnaces trials should be carried out with an all-basic wall lining constructed of high-density PShSP-type brick on MF-1-type magnesite — phosphate mortar and a roof lining constructed of MKhS brick and the same mortar.Translated from Ogneupory, No. 4, pp. 44–49, April, 1976.     

Beneficiation of aluminosilicate and magnesia secondary refractories

Conclusions The use of magnetic separation will enable us to separate from the refractory scrap, metal, slag, and refractories from the working zone impregnated with metal, and will ensure the production of standardized material in terms of chemical and grain-size composition and refractoriness. The exception is the chamotte scrap from steel-melting articles because of the low refractoriness (1500°C).The magnetic separation should be carried out in stages with a high magnetic field strength.Translated from Ogneupory, No. 1, pp. 40–43, January, 1987.     

Obtaining aluminosilicate refractories by the hydrothermal method

Conclusions On the basis of aluminosilicate bond made from heat-processed hydrated alumina and quartz sand in the molecular ratio of Al₂O₃: SiO₂=32, in conditions of autoclave processing at 800–1000 kg/cm² in a period of 8–12 h, it is possible to obtain unfired aluminosilicate refractories with quite high physico-chemical factors.During the heating of the specimen after autoclave processing to the temperature of sintering, their strength diminishes to a small extent, which makes it possible to use these refractories directly in structures.The high strength of aluminosilicate refractories after autoclave processing is due to the formation of a gel-like hydrated aluminosilicate upon the interaction of Al(OH)₃ with SiO₂.The technology developed for the production of unfired autoclave firebrick and high-alumina refractories permits us to obtain large products which make it possible to industrialize their transportation and laying, and to reduce the number of joints in the lining.Translated from Ogneupory, No.1, pp.15–19, January, 1967.     

Future application of aluminosilicate refractories for aluminum electrolyzers. Part 4. Wettability of aluminosilicate refractories with molten industrial electrolyte and sodium fluoride

Optical microscopy is used to determine wetting angles for aluminosilicate refractories with molten industrial electrolyte and NaF. Kinetic wetting parameters and interaction of electrolyte with refractory are determined. It is shown that removal of silicon from refractory also occurs in the form of silicon monoxide. It is established that aluminosilicate refractories, prepared with addition of mullite-corundum chamotte, are wetted worse by fluoride salts, but the corrosion resistance of them is better than for refractories prepared by normal technology. __________ Translated from Novye Ogneupory, No. 1, pp. 17–21, January 2008.     

Abrasion resistance of aluminosilicate refractories for rotary kilns

Conclusions An investigation was carried out of the abrasion resistance of aluminosilicate refractories for rotary kilns by two methods, viz., on a sandblaster and on a grinding wheel. The first method gave more precise and reliable results. The test conditions on a sandblaster are optimal with an air pressure of 1.5 kgf/cm².The results of the investigation of the abrasion resistance and its variation with the elastic and strength properties of aluminosilicate brick were evaluated by methods of mathematical statistics. It was found that the abrasion resistance of aluminosilicate refractories depends largely on the strength and elastic modulus of the product.The abrasion resistance determined on a sandblaster is a reliable criterion for a prediction of the potential durability of refractories in the cold zones of rotary kilns.The bricks produced by the Novomoskovsk Refractories Plant from semiacid clays are more resistant to abrasion than the chamotte bricks produced by that Plant, a fact which is demonstrated by the performance of these brick types in the rotary kilns of the Achinsk Alumina Combine and the Magnezit Combine.Translated from Ogneupory, No. 5, pp. 42–46, May, 1978.     

Prospects for using aluminosilicate refractories for aluminum electrolyzers. Part 2. Resistance of aluminosilicate refractories to the action of commercial electrolyte

Data are provided for laboratory studies of the resistance of aluminosilicate refractories to the action of commercial electrolyte. It is established that refractory ShPD_M-45, prepared using a mullite-corundum chamotte, is most resistant to electrolyte action. Results are provided for studies in the change of mineral composition and phase transformations in aluminosilicate refractories during reaction with commercial electrolyte. It is shown that long-prismatic titanium-containing mullite is more resistant to the action of the fluoride ion than short-prismatic material. __________ Translated from Novye Ogneupory, No. 10, pp. 26–32, October 2007. Part 1 of the article was published in Novye Ogneupory No. 9 (2007).     

Main factors affecting the thermal stability of aluminosilicate refractories

It is shown that the partial pressure of oxygen and thermocycling in variable gas media are the main factors characterizing the thermal stability of aluminosilicate refractories. The obtained functional dependences of the variation of the properties of the refractories are described by equations.     

Improving molds for electrofusion cast refractories

Conclusions Great strength and adequate gas permeability are possessed by molding mixtures of quartz sand and also by a mixture of quartz sand and marshalite. These mixes possess high flowability, low friability and are easily molded.Use of water glass for a bond reduces the drying time of the molds and confers excellent exploitation properties.The quality of the working surface of the molds and their refractoriness can be increased by applying protective coatings.Use of nonsplit-type molds gives better castings compared with products cast in split molds.     

Prospects for using aluminosilicate refractories for aluminum electrolyzers. Part 1. Features of the structure of aluminosilicate refractories intended for aluminum electrolyzers

Comparative analysis is provided for the structure and properties of aluminosilicate refractories grade ShPD. It is established that refractory ShPD_M-45, produced with the use of an addition of mullite-corundum chamotte surpasses in all characteristics refractories prepared by the normal technology. Refractory ShPD_M-45 may be recommended for use in aluminum electrolyzers. __________ Translated from Novye Ogneupory, No. 9, pp. 20–23, September 2007.