High-density kaolin refractories

Conclusions A technology was developed for the production of high-density kaolin refractories with a porosity not over 10%. Trial batches of these refractories were produced at the Zaporozhe Refractories Plant.It was shown that these high-density refractories can be produced by making use of two different chamottes, viz., chamotte from Polozhsk kaolin in the coarse-grained part and chamotte from Novoselitsy kaolin in the fine-ground parts of the compositions.Translated from Ogneupory, No. 1, pp. 8–14, January, 1978.     

High-density kaolin refractories

Conclusions A technology was developed and tested in semifactory conditions for producing kaolin refractories with a porosity of less than 13%, prepared on the basis of Vladimir kaolin. The test results were positive. Using this technology we specified the use of finely dispersed chamotte or of a mixture obtained by the joint grinding of chamotte and kaolin with additions of triethanolamine and bentonite.Translated from Ogneupory, No. 4, pp. 17–21, April, 1973.     

Cordierite ceramics—Spalling-resistant high-melting refractories

Conclusions The production technology of cordierite refractories from fireclay and magnesite differs from other processes in that the components have to be finely ground.The components must be accurately apportioned and the mass thoroughly mixed preferably in batch mixers. Otherwise, the production process of cordierite refractories does not differ from that of chamotte brick.The use of fireclays with a high Al₂O₃ content (38%) and magnesite eliminates the need for commercial alumina.     

Refractories from Murzinsk chamotte

Conclusions The Chasov-Yar refractories combine has developed and introduced the manufacture of ladle articles with a mass proportion of Al₂O₃ of not less than 39% on the basis of chamotte made from Murzinsk kaolin. The properties of the articles correspond to the requirements of GOST 5341-69.Translated from Ogneupory, No. 8, pp. 41–43, August, 1986.     

Mastering the production of dense kaolin refractories for blast furnaces

Conclusions The Ukrainian Institute of Refractories has developed a technology, and the Chasov-Yar Factory is mastering the manufacturing methods, for dense kaolin refractories with a porosity of not more than 12% for blast furnaces. The bricks are made with high-fired chamotte using Novoselitsk and Polozhe kaolins. Firing is done in tunnel kilns with a setting height of 1.95 m.The increase in apparent density to 2.35–2.36 g/cm³ in the green brick due to rational use of kaolin chamotte and the improvement in body processing facilitate the regular production of goods with a porosity of not more than 12%, using existing SM-1085 toggle presses and tunnel kilns with a high setting.Translated from Ogneupory, No. 5, pp. 6–12, May, 1979.     

Main causes of refractory wear in the shaft of a blast furnace and means of improving the resistance

Conclusions During service, refractories in a blast furnace shaft are saturated by components of the batch, change their properties and phase composition, and acquire a zoned structure which reduces the resistance to the complex action of the physicochemical and thermomechanical destructive factors.The wear of the shaft is a maultistaged cyclic process, including the saturation of the refractories through the pores, joints, and cracks by liquid and gaseous components of the batch and the gaseous medium, the decomposition of mullite and the formation of new compounds and glass — mainly potassium phyllitic and nepheline compounds — solution and reduction of the new compounds, and abrasion of the reaction products by the batch materials.We recommended for the lining of the shaft shoulders and the bottom and upper parts of the hearth the use of dense kaolin refractories containing 41–42% Al₂O₃ and with an open porosity of 8–12%, the technology for which is being introduced at the Chasov-Yar Refractories Combine.Translated from Ogneupory, No. 4, pp. 41–45, April, 1980.     

Aluminosilicate Refractories Based on High-Alumina HCBS.

Ceramic concrete specimens are prepared based on HCBS of mullite-silica composition (58% Al₂O₃) and fillers of similar and chamotte compositions, having markedly better properties than for traditional refractories with the same Al₂O₃ content. An ultimate strength in compression of 150 – 250 MPa with porosity of 6 – 11%, and a temperature for deformation under load T _g of 1540 and 1460 MPa are obtained correspondingly for ceramic concrete specimens with an Al₂O₃ content of 58 and 42%. With respect to T _g, mullite-silica ceramic concretes (58% Al₂O₃) correspond to traditional mullite (62 – 72% Al₂O₃), chamotte (42% Al₂O₃) and mullite-silica (45 – 62% Al₂O₃) refractories.     

Technology for producing large dense kaolin blocks

Conclusions The Ukrainian Scientific-Research Institute of Refractories has developed the main technical parameters for obtaining dense kaolin products with relatively moderate specific pressing pressures (about 500 kg/cm²), The Podol'sk Refractories Plant produced an experimental batch of kaolin blocks with a porosity of less than 12% based on chamotte made from Novoselitsk kaolin. The main properties of the kaolin blocks are better than those required by GOST for brick class-A produced for blast furnaces, and correspond to the properties of dense kaolin blast furnace brick.Translated from Ogneupory, No. 6, pp. 2–6, June, 1971.     

Making high-alumina products using Troshkov clay

Conclusions Laboratory and industrial experiments confirm the possibility of producing high-alumina products using Troshkov clay. The experimental brick (about 62% Al₂O₃) made from Troshkov clay and calcined alumina, prepared by the technology involving the use of high-chamotte refractories and fired at 1520°C, possesses equivalent or higher properties than the same products based on Latnensk.The high-alumina bond containing Troshkov clay is inadequately sintered with the grains of chamotte. In order to obtain more densely sintered products it is necessary to increase the content of fine fractions of the components (<0.063 mm) in the bonding part of the batch during their combined grinding, or to increase the firing temperature of the brick.Translated from Ogneupory, No. 7, pp. 6–11, July, 1971.     

More efficient utilization of alumina in refractories production

Conclusions An investigation was carried out of ways of utilizing commercial alumina more efficiently in refractories production by improving the composition of the products and the technology of their manufacture. Commercial alumina should be used mainly for the production of mullite refractories from synthetic mullite and of corundum refractories containing 90–99% Al₂O₃. Commercial alumina must be used for the production of spinel and spinel-containing refractories.More extensive use should be made of the alumina-containing waste from chemical plants for the production of refractories with a low mullite content, of ramming compounds, fusioncast refractories, and electrofused spinel as a substitute for chromite in roof bricks. To produce refractories with a higher Al₂O₃ content than can be achieved with kaolin more extensive use should be made of natural alumina-containing starting materials.Some mullite and corundum refractories should be produced with low porosity by using high molding pressures, actively sintering starting materials, and hydrostatic molding.Translated from Ogneupory, No. 8, pp. 33–39, August, 1978.     

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.     

Electrofused refractory based on tumanyan stoney clay and commercial alumina

Conclusions A technology was developed for making fused-cast refractories of mullite composition from stone-like Tumanyan clays and commercial alumina for the structures of the lower courses of the walls of glass tank furnaces. The experimental refractories are 50–100% more glass resistant than normally used fireclay and high-alumina refractories made by the ceramic technology. The introduction into the composition of the batch of up to 10% ZrO₂ does not greatly improve their properties.According to approximate calculations, the use of electrofusion cast mullite experimental refractories is economically desirable.Translated from Ogneupory, No. 3, pp. 21–25, March, 1967.     

Firing technology for refractories made of sintered corundum

Conclusions A technology was developed for firing corundum refractories, which, when used with a batch containing densely sintered chamotte having a water absorption of up to 3%, 40–45% finely milled corundum (minus 60 m), and a fabrication pressure of 100 MPa, guaranteed the production of dense goods, and with the use of slightly sintered chamotte having a water absorption of up to 12% — high-density goods. With a reduction in the fabrication pressure of the green articles to 50 MPa the new technology ensures the production of densified goods.Translated from Ogneupory, No. 5, pp. 15–20, May, 1979.     

Refractories from kaolins of the Angrenskoe deposit

Samples of kaolin from the Angrenskoe deposit have been investigated by specialists from the Tashkent Stromproekt Research Institute and the St. Petersburg Institute of Refractories. Semiindustrial batches of articles from Angrenskoe kaolin were produced by the experimental technological department of the St. Petersburg Institute of Refractories. It was established that the experimental articles meet the requirements of GOST 390-83 for chamotte articles of grades ShA and ShB. Angrenskoe kaolins can be a raw material for the production of chamotte and semiacid refractories for various purposes.Translated from Ogneupory, No. 2, pp. 25–28, February, 1995.     

Improving the strength of chamotte-kaolin refractories

Conclusions In the production of chamotte products including standard sizes, on the basis of Vladimirovsk kaolin without the use of plastic clays, it is necessary to introduce finely milled chamotte into the bond part of the batch due to the sandiness and low plasticity of the kaolin; the chamotte content must be increased to 70–80%, and small additions of sodium tripolyphosphate made to the moistening slip.The increase in the strength of the chamotte-kaolin articles with the use of sodium tripolyphosphate is attained on account of the plasticizing and sintering action of this additive. The action of the additive is manifest with any concentration of chamotte in the compound including the case when clay is added to the bond part of the batch. Adding small amounts of sodium tripolyphosphate does not increase the cost of the goods.Translated from Ogneupory, No. 4, pp. 16–20, April, 1981.     

Refractories based on a laminar corundum chamotte

Conclusions It is shown that the porosity of laminar corundum chamotte determines the porosity of the specimens manufactured from it.On the basis of the laminar chamotte we have obtained corundum refractories with excellent characteristics. An experimental technology for the refractories has been developed on the basis of the laminar corundum chamotte in corundum and corundum-mullite bondings.Translated from Ogneupory, No. 3, pp. 46–50, March, 1981.     

Production of dense refractories for blast furnace shafts

Conclusions The Zaporozhe Refractories Plant with the help of the Ukraine Refractories Research Institute has produced a batch (1100 tons) of kaolin brick with a porosity of not more than 12% for a 2700 m³ blast furnace at the Krivoi Rog Steel Factory. The brick made on toggle presses from Noveselits chamotte using Chl clay as the bond had outstanding quality factors which were obtained by stabilizing the industrial production parameters, increasing the firing temperature, and carefully controlling the grain-size composition.Translated from Ogneupory, No. 7, pp. 7–11, July, 1968.     

Lightweight refractories semidry-molded from Borovich clay

Conclusions It was shown in a laboratory investigation that in the production of lightweight chamotte refractories by semidry molding it is difficult to achieve the strength specified by the relevant All-Union State Standard. The strength depends mainly on the chemical and mineral composition and the properties of the binder clay and on the ash content of the burn-out additive.With high-sintering, semirefractory Lyubytin clay as binder and petroleum coke with an ash content below 1% as burn-out additive the finished refractory product had an apparent density of 1 g/cm³ and a cold-crushing strength of 7–17 kg/cm². The strength of the refractory was increased by adding a substance containing alkali or CaO to the batch, more particularly expanded perlite.An experimental batch of lightweight chamotte refractories of apparent density 1 g/cm³ was produced from Borovich plastic clay from the Ust'-Brynkino Sector and coal coke fines from a UDSC. Without added sintering substances the cold-crushing strength was 24–38 kg/cm² (i.e., 30 kg/cm² on average).Translated from Ogneupory, No. 6, pp. 9–15, June, 1976.     

Study of the service of high-alumina and kaolin refractories in the checkers and structure of blast-furnace stoves

Conclusions The structure of kaolin brick in the high-temperature zone of the stove after 6.7–7.2 years service at subcupola temperatures of 1300°C underwent substantive external and structural changes.In the structure of the stove made from high-alumina brick VGO-62 after six years service we detected substantially less change.In the kaolin brick of the upper rows of the checker three clearly defined zones are formed: working (slag), impregnated with alkalis, the transition zone (porcelain-type), and the least-changed zone. During the service of high-alumina refractories mullite crystallizes, which confirms the results of work carried out previously.Owing to the creep of kaolin and high-alumina refractories 4–5% shrinkage of the brick occurs in the upper rows of the checker, and at a depth of 2.5–6.0 m — 1.5–2.0%. The height of the checker diminishes under these conditions by 0.8–1.0 m.The densification of the structure of the upper rows of the checker corresponds to a reduction in porosity and an increase in the density of the brick.The temperature of initial deformation under load of 2 kg/cm² of the slagged kaolin refractories taken from the upper rows of the checker diminishes by 150–200°C, and in the lower layers of the checker it does not alter. This factor for high-alumina refractories in service increases by 160–190°C. In the high-temperature zone of the stoves it is desirable to test dense, high-alumina refractories containing 72–75% Al₂O₃.Translated from Ogneupory, No. 5, pp.14–19, May, 1972.     

Mullite corundum articles for electric furnace roofs

Conclusions Using a method developed by the Institute we produced an experimental batch of synthetic mullite-corundum refractories containing more than 72% Al₂O₃. The properties of these refractories exceed similar properties for regularly produced articles close in composition, which enables us to recommend them for use in the roofs of arc electric steel-melting furnaces.The experimental batch of synthetic mullite-corundum articles is being sent for testing in DSP-100 furnaces at the Chelyabinsk Metallurgical Combine.Translated from Ogneupory, No. 7, pp. 22–25, July, 1986.