SilplateTM Structural Insulating Board. The Revolutionary Lining System For Processing And Transportation Of Molten Metal

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1 SilplateTM Structural Insulating Board The Revolutionary Lining System For Processing And Transportation Of Molten Metal

2 The Silplate TM Lining System Silplate TM is a structural insulation board with revolutionary characteristics. It is a unique product currently offered by Unifrax that is able to withstand high temperatures while maintaining high compressive strength and low thermal conductivity. Silplate s physical properties do not change, even under the highest operating temperatures, assuring physical stability to the complete refractory system. Utilizing a Silplate back-up lining results in a reduced shell temperature, fewer joint attacks on the working lining bricks and significant energy savings, while potentially increasing the volume of the ladle. Physical Properties Silplate Lining System Color White White Green Operating Temperature 2012 F 2012 F 2444 F Basic Composition Silica & Alumina Silica & Alumina Alumina & Silica Density 50 pcf 62 pcf 50 pcf Thermal Conductivity Btu in/hrft 2 F Temperature..77 F Temperature.664 F Temperature.1100 F Temperature.1402 F Flexural Strength - psi 225 1, Hot Crushing Strength - psi (R100-Ceran F 2,698 5,395 4,641 Operating Temp. (%) <3.56 <3.23 <3.01 Iron Oxide (%) <0.5 <0.5 <0.5 Chemical Properties Silplate boards provide excellent chemical resistance properties when exposed to most acids and corrosion agents, except hydrofluoric, phosphoric, hydrochloric, and sulphuric acids and concentrated alkalis. Made with high purity materials, Silplate has a very low percentage of Fe 2 O 3 which allows flexibility in oxidizing or reducing atmospheres. Primary Advantages High thermal resistance Low thermal conductivity Excellent mechanical resistance Dimensional stability Typical Applications Ladles and torpedo cars Trough runners and tundishes Insulation of electric arc furnaces

3 Criteria For Selecting Insulation For Molten Metal Transportation Equipment Compression Strength Transportation of molten metals requires as much caution as other operations in the production of iron and steel. Since large volumes of molten metal are transported in ladles and torpedo cars, the refractory lining system including the backup insulation, is exposed to high compression loading. During the operating life of the ladle lining, up to two thirds of the sidewall refractory may be consumed. At the end of the lining campaign, the insulating material must support the total weight of the molten metal contained in the ladle. The dense volume of molten metal presses the refractory lining against the casing and if the back-up insulation material does not have adequate compression strength, it will be crushed causing a shifting of the working lining bricks. This action will increase the joint attack by the molten metal or even cause cracks in monolithic working linings. Interface Temperature High performance refractory materials including dolomite, magnesia carbon or alumina carbon are typically selected for the working linings of molten metal transfer equipment. These materials are selected in order to maximize service life of the refractory. The thermal conductivity of these working lining materials is very high, therefore a back-up material with high temperature stability and low thermal conductivity is required. Because of its low shrinkage, high compressive strength and low thermal conductivity, Silplate structural insulating board is able to meet these requirements. Silplate can operate at interface temperatures of up to 2444 F while maintaining its physical integrity. In some applications, the use of Silplate back-up allows the reduction in the thickness of the safety lining. This reduction in total lining thickness increases the volume of molten metal transported, while achieving a balance between safety and productivity. Molten Metal Resistance To understand the performance of ladle back-up insulation when in contact with molten metal, a test was performed with iron slag. This test compared the metal resistance of magnesia silicate insulation and Silplate structural insulating board. Magnesia silicate boards (on the right side of the photo) react with the molten metal slag causing degradation of the material. This low resistance to molten metal contact is due to low refractoriness and the presence of iron oxide in the composition of the product. Silplate (on the left side of the photo) does not have any reaction with molten metal slag.

4 Performance Of Silplate Insulation Boards Iron or Steel Transportation Ladles Based on thermal modeling and the customer s operating data, Unifrax has been able to redesign refractory linings to utilize Silplate 1308 as back-up insulation in transfer ladles. Typically the thickness of the safety lining in the refractory system can be reduced when Silplate is added to the system. This reduction in overall lining thickness increases the ladle s capacity for molten metal, eliminating bottlenecks in the steelmaking process. Note that significant improvements in ladle capacity are obtained while maintaining ladle coldface temperatures in accordance with the parameters established in AISI Technical Report #9 (Specifications for Design and use of Ladles). This volume increase and productivity improvement are possible with Silplate 1308 due to its superior thermal and mechanical performance at interface temperatures up to 2444 F. In addition, the use of Silplate as back-up insulation may increase the teeming time due to reduced temperature loss in the molten metal. Torpedo Cars Molten iron torpedo cars generally use an alumina-silicon carbide-carbon brick as a working lining and 60% Al 2 O 3 bricks as a safety lining. Despite their high thermal conductivity, torpedo car refractory systems typically do not develop a critically high interface temperature, such as those found in magnesia carbon brick systems. Interface temperatures between the safety and back-up lining usually remain below 1832 F. Compressive strength is the most critical property required for long service life as back-up insulation in this application. The acceleration or deceleration of the torpedo car places strong pressure in the cone regions of the vessel. To address this need, Silplate 1112 with a hot crushing strength over 5,000 psi was developed. Tundish Magnesia based castables, typically used as the working lining in the tundish, have high thermal conductivity. Heat loss resulting from the use of highly conductive refractory materials can accelerate the loss temperature in the metal and overheat the tundish shell. One solution to this operating problem is the installation of a back-up insulation material with low thermal conductivity for improved thermal efficiency. Silplate 1108 is recommended in this application in order to maintain acceptable casting temperatures and minimize the potential for warping of the shell casing. Trough Runners Many of the insulating board products used as back-up insulation in iron troughs have an organic content of up to 8%. This organic binder, which typically burns out at temperatures higher than 250 F, does not receive enough oxygen for complete combustion in the trough application. In the absence of oxygen, the organic binders are carbonized, changing the boards thermal conductivity. By using an inorganic back-up insulation, Silplate 1108, in place of traditional insulating boards, the material performance remains unchanged. Silplate ensures the stability of the physical and chemical properties of the lining system.

5 Silplate: The Ideal Balance Between Safety And Productivity The steelmaking process (including the vessels used for molten metal transfer) has undergone continuous improvement with an increasing emphasis on efficiency and safety. To address the changing needs of the industry and meet specific customer requirements, the refractory industry currently offers a range of high performance materials engineered for long service life. Improvements in refractory compositions for ladle working linings have resulted in materials with better resistance to severe thermal, mechanical and chemical conditions. One tradeoff for this improved performance is the high thermal conductivity exhibited by these new materials. To maximize the performance of these refractories and assure safe operating conditions, a high performance structural insulating board should be used to back up the working and safety linings in molten metal transfer applications. Historically, products that have been used as back-up insulation in molten iron and steel transfer vessels exhibit only one or two of the performance criteria listed below: High hot compression strength Low thermal conductivity Refractoriness ( high continuous use temperature) Resistance to molten metal attack To match the performance of the back-up lining with advanced ladle refractory, Unifrax developed Silplate structural lining board, a revolutionary material designed to meet all requirements of molten metal processing. The Silplate lining system supports high temperatures, has high compressive strength, resists attack by molten metal and maintains low thermal conductivity.

6 Corporate Headquarters USA Unifrax I LLC 2351 Whirlpool Street Niagara Falls, NY Telephone: Telefax: European Headquarters Unifrax France, SA 17 Rue Antoine Durafour-BP Lorette France Telephone: +33 (0) Telefax: +33 (0) Form C Unifrax I LLC Printed in USA All rights reserved The information, recommendations and opinions set forth herein are offered solely for your consideration, inquiry and verification and are not in part or total, to be construed as constituting a warranty or representation for which we assume legal responsibility. Nothing contained herein is to be interpreted as authorization to practice a patented invention without a license. All trademarks and registered trademarks used herein are the sole property of Unifrax I LLC.