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Chakrabarti A.,TRL Krosaki Refractories Ltd | Ghosh B.,TRL Krosaki Refractories Ltd | Adak S.,TRL Krosaki Refractories Ltd | Panda P.B.,TRL Krosaki Refractories Ltd | And 3 more authors.
Proceedings of the Unified International Technical Conference on Refractories, UNITECR 2013 | Year: 2014

Alumina-Chrome-Zirconia system is well known for its outstanding thermo mechanical properties and corrosion resistance towards various metals and slag. Phase diagram of alumina-chrome system shows a complete solid solution throughout the whole range without forming any eutectic phase which is mainly responsible for its excellent corrosion resistance property. Presence of zirconia in alumina-chrome system improves thermal shock resistance of the refractory by virtue of creation of micro-cracks within the matrix. It also helps to enhance the thermo mechanical strength of the system. The present article describes the development of alumina-chrome-zirconia refractory having some unique characteristics for application in copper smelters, incinerators, pelletization furnace, glass tank furnaces etc. High purity raw materials like fused corundum, reaction bonded chrome oxide and specially designed monocilinic zirconia with optimum granulometry were selected for design of the product. The latest process technology of mixing, pressing and firing at ultra high temperature was adopted for its commercial manufacturing. The developed products were thoroughly characterized for AP, BD, CCS, RUL, HMOR and chemical analysis. The final product with optimum properties was tested for X-Ray Diffraction, Scanning Electron Microscopy, slag corrosion resistance and thermal shock resistance. This specially designed product was put into operation in ISA smelting furnace in one of the leading copper manufacturing industry and the product is running successfully in the aforesaid area of application. © 2014 The American Ceramic Society.


Rana R.P.,TRL Krosaki Refractories Ltd | Padhy B.P.,TRL Krosaki Refractories Ltd | Bal A.S.,TRL Krosaki Refractories Ltd | Adak S.,TRL Krosaki Refractories Ltd | And 2 more authors.
Proceedings of the Unified International Technical Conference on Refractories, UNITECR 2013 | Year: 2014

Reaction sintering of dolomite with alumina forms MgAl2O3CM and calcium aluminate phases depending upon the ratio of the reactants and temperature. The nonisothermal densification behavior of the composite powder was studied for the determination of sintering temperature. The phase formation, densification of the aluminadolomite mixer as a function of temperature was studied. The co-grounded powder mixed with binder was formed to rectangular clots and sintered at 1550°C.The fired clot was crushed and grounded into different size fractions required for the refractory brick pressing. The properties e.g. porosity, density, crushing strength, hot modulus of rupture and thermal conductivity of the brick fired at 1520°C were determined. The porosity and pore size distribution and wetting behaviour of the refractories determine the extent of the molten aluminum contact and its infiltration. The Al resistance of the alumino-silicate and spinel-calcium aluminate bricks was tested against pure Al (A-7 grade) in the similar condition (850°C/72hrs). The spinel-calcium aluminate brick showed non wetting characteristics and no impurity pick up from the brick to the Aluminum metal after the corrosion test. Thermal spalling resistance and thermal expansion behavior of the brick were determined for the confirmation of application in the Aluminum Industry. © 2014 The American Ceramic Society.


Mukhopadhyay S.,TRL Krosaki Refractories Ltd | Chattopadhyay A.K.,TRL Krosaki Refractories Ltd | Das G.C.,Jadavpur University
International Journal of Applied Ceramic Technology | Year: 2014

The effect of MgO grain size on the permanent linear change behavior of resin bonded alumina-magnesia-carbon refractory has been studied in relation to the formation of spinel phase in these refractories as a function of firing time and temperature. From scanning electron microscopic studies, spinelization at the interface of Al2O3 and MgO grains has also been studied to determine the reaction kinetics for gaining insight into the process. © 2013 The American Ceramic Society.


Bag M.,National Institute of Technology Rourkela | Adak S.,TRL Krosaki Refractories Ltd. | Sarkar R.,National Institute of Technology Rourkela
Ceramics International | Year: 2012

Development of low carbon containing MgO-C refractories has been studied containing a fixed 0.9 wt% of nano carbon and 1-9 wt% of flake graphite. Refractory compositions were prepared and processed as per the conventional manufacturing techniques of MgO-C refractory. Properties of the different compositions were evaluated and also compared against the conventional MgO-C refractory containing 10 wt% graphite prepared under exactly similar conditions. Addition of 3 wt% of flake graphite in combination with 0.9 wt% of nano carbon black was found to be optimum and resulted in better/comparable properties to that of conventional MgO-C refractory. © 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.


Bag M.,National Institute of Technology Rourkela | Adak S.,TRL Krosaki Refractories Ltd. | Sarkar R.,National Institute of Technology Rourkela
Ceramics International | Year: 2012

Development of nano carbon containing magnesia carbon refractories has been studied to reduce the total carbon content, thereby reducing the heat loss from the metallurgical process and producing more eco-friendly refractories. The carbon contamination from refractory to liquid metal will be minimized using low amount of nano carbon. Different percentages of nano carbon are used in combination with graphite as carbon source and the total carbon is maintained below the half of the total carbon of the conventional MgO-C refractories. The compositions were processed as per the conventional manufacturing techniques and the properties were evaluated and compared against the conventional refractory prepared under exactly similar conditions. Also elemental mapping of carbon was done to study the distribution of the nano carbon in the matrix. © 2011 Elsevier Ltd and Techna Group S.r.l.


Das R.R.,TRL Krosaki Refractories Ltd | Das R.R.,National Institute of Technology Rourkela | Nayak B.B.,National Institute of Technology Rourkela | Adak S.,TRL Krosaki Refractories Ltd | Chattopadhyay A.K.,TRL Krosaki Refractories Ltd
Materials and Manufacturing Processes | Year: 2012

Nanopowders of magnesium aluminate (MgAl 2O 4) spinel, prepared through citrate-nitrate gel method and calcined at 800C, were incorporated to the matrix of magnesia-carbon (MgO-C) refractory. The physical and chemical properties of the nano-MgAl 2O 4 spinel-added (0.5 and 1.0wt%) MgO-C bricks were compared with those of MgO-C bricks containing no spinel and commercially available micron-sized (<45m) stoichiometric spinel (AR-78). It was observed that nano-spinel (NS) (1wt%) containing MgO-C refractories effectively prevents the oxidation, slag corrosion, and penetration resistance compared to MgO-C bricks with or without micron-sized spinel added. The average pore diameter decreases, and the concentration of the fine pore increases with addition of nano-MgAl 2O 4 spinel in the matrix of MgO-C bricks. Due to the lower pore size and higher concentration of fine pores as well as higher amount of carbon retention, nano-MgAl 2O 4 spinel-added MgO-C bricks show better physical as well as chemical properties and may have potential applications in both steel and refractory industries. © 2012 Copyright Taylor and Francis Group, LLC.


Lipunov P.V.,VEO Tyazhpromeksport | Motrich S.V.,VEO Tyazhpromeksport | Markov V.I.,TRL Krosaki Refractories Ltd. | Chura N.G.,TRL Krosaki Refractories Ltd.
Coke and Chemistry | Year: 2014

Problems arising in the reconstruction of coke battery 1 at Isfahan steel plant are considered. The construction of coke battery 1 (coke-oven capacity 27.3 m3) with a PVR-51 dust-free coke-discharge system and bottom heating-gas supply is described. The losses of unprocessed coke-oven gas are calculated after coke-battery startup and after the elimination of leaks at seams in the refractory lining. Introduction of a method of detecting leaks at lining seams in the coke-oven walls reduces the losses of unprocessed coke-oven gas from 1738.73 to 44.6 m3/h. © 2014, Allerton Press, Inc.


Lipunov P.V.,OAO VEO Tyazhpromeksport | Motrich S.V.,OAO VEO Tyazhpromeksport | Markov V.I.,TRL Krosaki Refractories Ltd | Chura N.G.,TRL Krosaki Refractories Ltd
Coke and Chemistry | Year: 2014

The reconstruction of coke battery 1 at Isfahan Steel Works is considered. The structure of the Dinas component in the insulating walls at coke battery 1 with a PVR-51 system is described; this battery has bottom supply of the heating gas; the useful volume of a single oven is 27.3 m3. The research shows that drying and heating of the Dinas component by a burner with a protective casing protects the refractory surface of the insulating wall from an open flame during heating from 20 to 500°C. © 2014, Allerton Press, Inc.


Rana R.P.,TRL Krosaki Refractories Ltd | Bal A.S.,TRL Krosaki Refractories Ltd | Adak S.,TRL Krosaki Refractories Ltd | Chattopadhyay A.K.,TRL Krosaki Refractories Ltd
InterCeram: International Ceramic Review | Year: 2013

In recent years, mullite has drawn great attention because of its extraordinarily high temperature strength, creep resistance, chemical stability and low thermal expansion coefficient. Its mechanical properties at room temperature like fracture toughness are unfortunately very poor compared with other oxide materials like alumina and zirconia. Zircon-based materials enjoy wide application across different industries, especially steel, due to their superior properties at high temperature. Researchers are interested in using zirconia-mullite-based materials instead of zircon alone to combine the best aspects of both materials. Extensive research on the properties of zircon, zirconia, mullite and their ceramic composites has been carried out in the field of refractory applications. Zircon- mullite (ZRM) composite has been prepared in a variety of compositions by reaction sintering starting with different proportions of zircon. The effect of varying zircon percentage on densification, phase analysis and strength was measured. Thermal and thermo-mechanical properties (e.g. RUL, TSR, HMOR, RTE and PLC) were studied as a function of zirconia content. Phase analysis of zirconia-mullite-based composites showed the presence of free zircon which can provide better performance properties at high temperature. The formation of mullite phase improved both thermal shock and HMOR compared to non-mullite-based zircon and zircon- zirconia composites. © 2013 Expert Fachmedien GmbH.


Samanta A.K.,TRL Krosaki Refractories Ltd | Satpathy S.,TRL Krosaki Refractories Ltd | Adak S.,TRL Krosaki Refractories Ltd | Chattopadhyay A.K.,TRL Krosaki Refractories Ltd
Proceedings UNITECR 2011 Congress: 12th Biennial Worldwide Conference on Refractories - Refractories-Technology to Sustain the Global Environment | Year: 2011

Use of castables is increasing significantly in ferrous, non-ferrous and other industries due to several advantages over shaped items. Different properties of refractories are key measure to assess its performance. The most important properties are HMOR (Hot modulus of rupture), RUL (Refractoriness under load), creep, thermal shock resistance etc along with other physical properties. Several works have been conducted both in ultra low cement and low cement systems to improve all these properties by designing products with different raw materials. But in most of the cases shaped items show superior thermo-mechanical properties over low or ultra low cement castables. Use of calcium aluminate binder is common for designing castables to get initial strength. Control addition of casting water can enhance the initial strength and other physical properties. Several super fine materials have been tried to reduce casting water like reactive/calcined alumina, spinel, micro-silica etc. Addition of micro-silica has certain advantages as it gives cost effective products and help to form secondary mullite by reacting with reactive/calcined alumina present in matrix. But the amount of calcium aluminate binder and micro-silica has remarkable effect on different thermo-mechanical properties of low cement castables. In present work, 70% Al2O3 low cement castable has been designed with different calcium aluminate binder and micro-silica. Total amount for both is kept at 10% varying micro-silica from 2% to 8%. All relevant properties are measured for each batch along with other thermo-mechanical properties particularly HMOR. Probable explanations are given for different thermo-mechanical properties due to different amount of calcium aluminate binder and micro- silica in the system on the basis of phases formed during firing and micro structure analysis.

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