https://www.britannica.com/technology/refractory, The American Ceramic Society - Refractory Ceramics Division. The expression is mostly used in the context of materials science, metallurgy and engineering. An example of someone who is refractory is a person who refuses to listen to the rules. Mail. Refractory materialsare characterized by a high melting point, and when exposed to high temperatures they do not lose their strength and of form. Abst., 1963, 59, 3626 Often used in blast furnaces and cement rotary kilns, using shaped and predominantly unshaped materials, lining applications are some of the most common uses of refractory materials. Am. African Pegmatite proudly boasts a competitive and comprehensive product range and deals with the type of base materials you'd find in most refractory products. Refractory materials are an integral part of foundries and other high-temperature operations; chrome compounds can add useful properties to well-established materials. Coal dust (powdered anthracite), a relatively inexpensive and useful material, has a wide variety of uses in the refractory environment. Tech., 2002, 79, 245, 6          J. O. Nriagu and E. Nieboer (eds. Finally, refractory materials are used in certain glasses used for packaging, offering the glass a better level of thermal performance. Gunning mix               For applications requiring gunning machines for applying the material, Ramming mix             Widely used in the base of electric arc furnaces, Spraying mix               For spraying applications with special spraying machines, Coating Materials        Where coating methods are involved in the application, Patching mix               Manual patching work, Plastic                         Semi-wet and ready-mix applications for reparation uses in steel industries. Refractory Materials Market For GCC Steel Industry Market: Type Landscape Based on the type, the market saw maximum growth in the bricks segment in 2019. Fire clay/brick, chromite/chromite-magnesite and zirconia are classic examples of normal, high and super refractories respectively. Refractory materials are non-metallic materials whose refractoriness are no less 1580℃. Developed originally for the firing of clays for ceramic uses, pyrometric cones are small clay cones of known deformation points used inside the kiln, these deform when they reach a certain temperature, providing insight into the kiln temperature and the evenness of heating.). adjective hard or impossible to manage; stubbornly disobedient: a refractory child. Soc.,  1937, 36, 110, 11        US Patent US3360387A, 1967, expired, 12        E. T. Turkdogan, Ironmaking and Steelmaking, 2004, 31, 131, 27 Van Der Biji Street Mullite refractories are solidified by sintering in electric furnaces at high temperatures. Among many other applications across many types of industries, coal dust is used in the manufacturing of refractory bricks. 10        T. R. Lyman and W. J. Rees, Trans. Let us know if you have suggestions to improve this article (requires login). 2. The definition of which elements belong to this group differs. Fibres can then be aligned and pressed into boards, if needed. Meyerton 1960 Difficult to melt or work; resistant to heat: a refractory material such as silica. Naturally, the highest grading of refractory material will also be the most expensive. The chrome flour refractory allows this solution to be effective at high temperatures with long processing times. Also used in making bricks. Refractory materials must be chemically and physically stable at high temperatures. Refractory cement has good temperature performance and good plasticity, construction is convenient, has a strong bond strength and corrosion resistance, has a high refractory performance, good slag resistance, good thermal stripping. A PCE number of 33 roughly corresponds to stability of heating to 1,710 °C at a heating rate of 150 °C per hour, whereas a PCE of 15 is stable only as far as 1,425 °C at the same heating rate. Ceram. Used in making blends for ladle sand and nozzle sand. Non-ferrous metal production is the most common use for basic refractories. 32 synonyms of refractory from the Merriam-Webster Thesaurus, plus 91 related words, definitions, and antonyms. Get exclusive access to content from our 1768 First Edition with your subscription. Basic refractories, therefore, are most suited to when the atmosphere in the local environment and/or the slag produced will be basic as well. Ground glass powder is widely used in the foundry industry as a formulation in fluxes and in the manufacture of tundish liners. Refractory metals are a class of metals that are extraordinarily resistant to heat and wear. difficult to fuse, reduce, or work, as an ore or metal. Unshaped refractories are some of the most common materials utilised in the high temperature operations space. These materials are classified by multiple factors, with designations led primarily by the material’s chemical or physical properties, with physical characteristics further broken down into form, method of manufacture and fusion temperature. These materials are normally classified by their application use. As per the name, these refractories are fibrous, and they take this form through their manufacturing process which is akin to candy floss manufacture; broadly speaking a molten refractory is extruded and then spun, forming fibres. The first of the physical classification subcategories is form, this is where refractories are grouped by final appearance. The use of such insulation materials ensures more efficient heating of the boiler, less heat loss and therefore a lower energy requirement overall - saving the end user money. Our latest episode for parents features the topic of empathy. Refractory, any material that has an unusually high melting point and that maintains its structural properties at very high temperatures. According to withdrawn standard ASTM C-64, a plastic refractory is divided into 5 basic categories: high-duty fireclay, super-duty fireclay, 60% alumina, 70% alumina, and 80% alumina. [email protected]. Calination causes anthracite to undergo a graphitisation process at around 2,200 °C(5), at which point it also becomes more electrically conductive which is useful for smelting applications. Acidic refractories are those which react with bases (alkaline materials) at high temperatures. Magnesite, zirconia and dolomite are widely used refractories. A tundish acts as a reservoir and a distribution channel in the continuous casting of steels and aluminium. The three broad categories are shaped, unshaped (often referred to as ‘monolithic’, and also contains the major subcategory, castables) and fibrous. +27 16 362 0600 Taking the example of fire bricks, these are broken down into five subgroups of classification based on their levels of refractoriness, and thus this defines the environments in which they can be used, as follows. ‘Normal’ refractories perform in the range of around 1,500 to 1,800 °C; ‘high’ refractories from approximately. Some of the most common examples of acidic refractories include fire clay, silica and aluminosilicates. ry. Updates? Anywhere a high temperature needs to be tolerated, protected from or maintained, it is highly likely that a refractory material is present in one form or another. Although it seems counterintuitive to use as a refractory, anthracite is another material which can be added to clays or other materials to give them an enhanced degree of refractoriness, particularly when the anthracite itself has been calcined either by conventional or electrically assisted heating. Showing or characterized by obstinate resistance to authority or control: refractory children; refractory behavior. it acts as an acidic refractory. Information and translations of refractory in the most comprehensive dictionary definitions resource on the web. Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. Chromite is the only naturally occurring ore of chromium. Chrome sand is used in high-quality castables for producing precision castings when held together using organic resin- or inorganic type- binders. They consist of alumina, magnesia, silica, lime, and other metal oxides. Disclosed herein are one or more of a washcoat layer and/or an overcoat layer formed using a slurry that includes one or more of an oxygen storage material, a refractory support oxide, iron, and rhodium. African Pegmatite is a leading supplier and processor of high quality refractory materials, milled to exacting specifications. A complex field, where the right choice of refractory can be a difference between process success and failure, African Pegmatite stands ready to advise and supply the highest quality refractory materials, without which the world would be a very different place. What does refractory mean? Soc. African Pegmatite provides the materials to create specific shaped and custom bricks, including those containing silica, ground glass, anthracite and many others, for a broad range of shaped refractories. Bentonite is a form of clay that has found numerous uses over its thousands of years of use - but perhaps most notably in foundries from the 1900’s onwards, alongside powdered coal. Various base substances within these example categories might be coal dust, refractory chrome, refractory chrome sand, and glass powder. Refractory refers to the mechanical strength of the material at high temperatures. One particularly attractive property of ground glass when used in a tundish or a furnace lining is that it is able to remove iron oxide from molten iron and steel(12). What remains on the crust are what are known as refractory materials. Aside from as a fuel, anthracite finds use in high temperature applications - especially when calcined - due to its relatively high resistance to thermal shock, strength and chemical inertness. Definition of refractory in the Definitions.net dictionary. It has a highly corrosion-resistant nature to it which prolongs the life of the kiln. Home » Industry Resources » Refractory » Refractory, what is it and what does it do? Carbonaceous materials in the mold, such as high-anthracite coal dust can prevent such defects from forming. refractory material definition in English dictionary, refractory material meaning, synonyms, see also 'refractor',refractorily',refractometry',refract'. There are other criteria applied to these materials too, such as classifications by service temperature and bulk density and other variable temperatures such as thermal conductivity, load-bearing, and insulating properties. Refractory materialsinclude natural ores and various products made by certain purposes and requirements through certain processes, which have certain high-temperature mechanical properties and good volume stability. Dense refractories are … This second type of mortar is used more in applications needing load bearing such as kilns, towers, stacks and roofs. This makes it a more cost-effective resource. Soc. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. Learn more. Boasting a melting point of 2,040°C, it has the luxury of being “almost chemically inert”(6). These refractory standards help materials science laboratories, material processing companies, product manufacturers, and other producers and users of such materials and products in their proper fabrication and treatment procedures to ensure good quality and workmanship towards safe utilization. See more. Kaolin has the ad- 3. Foundry burn on is a name given to a wide variety of surface defects that are produced at high heat during the metal sand casting process. A further way of differentiating refractory materials is their method of manufacture, which itself is a proxy for their end use cases, and these refractory materials are often named after their specific applications and are usually selected based on their specific application needs. Refractories definition: unmanageable or obstinate | Meaning, pronunciation, translations and examples Furthermore, chromium-based filler sands are preferred and widely used in the foundry industry. Bull., 1980, 59, 4 Green sand is a compound mixture used for casting of metals, the most widely used moulding type in furnace and foundry applications. These applications range from furnaces and kilns to incinerators, and even reactors. PCE stands for pyrometric cone equivalent, and is a broad measure of the heat tolerance of a material, with higher PCE numbers corresponding to greater stability at higher temperature, thus it can be stated that these classifications are related to the softening temperature of the material. Some of African Pegmatite’s leading products are listed below. Coeditor of. Indeed, refractory bricks can also be manufactured using mostly chromite alone(8). Broadly speaking, any material type is best suited to a refractory environment that is akin to it. They are the most stable of the aluminosilicate refractories and have excellent resistance to high-temperature loading. Please select which sections you would like to print: Corrections? They all share some properties, including a melting point above 2000 °C and high hardnessat room temperature. Among the refractory forms, preformed shapes and castables are expected to see the best growth, while from a materials perspective, nonclay materials will outperform clay refractories. Chrome flour is used in the production of chrome magnesite refractory bricks, these kinds of bricks are mostly used in the construction of certain types of furnaces and kilns. 2          M. L. Van Dreser and W. H. Boyer, J. 1,800 to 2,000 °C; and super refractories are those with a fusion temperature in excess of 2,000 °C. the case, nozzle inlets, case closures, includes cured or semi-cured compounded rubber components comprising sheet stock containing an insulating or refractory material. ‘Such refractory materials as silicon dioxide and aluminum oxide are so severely attacked that their use is hazardous.’ ‘Some compounds of hafnium are also used as refractory substances to line the inside of high-temperature ovens.’ ‘Also under investigation as possible container materials are certain types of refractory ceramics.’ 1          J. Resistant to treatment: a refractory case of acne. These products represent some of our highest standards of work in refractories and refractory products. ry. 1. Aside from the aforementioned fire blankets, other common forms of low-level refractory material uses include fire bricks surrounding the fireplace, garden fire pits, aspects of the components of the lower part of chimneys and even the mortar holding the bricks together. Resistant to treatment: a refractory case of acne. More heat-resistant than metals, they are used to line the hot surfaces found inside many industrial processes. Refractory cement as a hot selling refractory materials, widely used in coke oven, glass furnace, blast furnace and other industrial furnaces. Silica is the primary component of glass, and hence ground glass behaves in a similar way to silica in the refractories space, i.e. ), Chromium in the Natural and Human Environments, Wiley-Interscience, New York, 1988, 7          E. Ruh and J. S. McDowell, J. In the traditional fire brick, ground glass has been added to silica to form fire bricks especially suited to glass-making furnaces. Refractoriness means the degree of centigrade temperature in which the conical sample of refractory is resistant to high temperature without … Filler sands are without question a necessity in steel production. However, that is not to say that valid and useful classification by method of manufacture and by fusion cannot be drawn. The calined version is more porous than untreated anthracite which also adds to its strength. Castables are a crucial and widely used subset of unshaped refractory, where a refractory is as part of a non-solid material which is poured and then cures in situ. Chromite refractories are valued for their high levels of resistance to deformation. clays refractory materials. Enrich your vocabulary with the English Definition dictionary Used in the production of chrome magnesite bricks by way of a refractory cement mix, these bricks are then used in the construction of certain high temperature furnaces and kilns. Refractory materials are an essential part of modern industry, providing for a wealth of manufacturing processes. Glass powder isn’t just good for making new glass - it also has applications in the furnaces used to make glass and beyond. 2SiO3 and an alumina content of approximately 70 percent. The final and one of the most crucial factors to sort between refractories is fusion temperature, and it is often the final arbiter to which refractories are rated. FibreCast offers an extensive line of fiber-formed refractory products and solutions that utilize best-in-class-materials, and bring you the benefits of our relentless pursuit of innovation. Global production for the metal, glass, and ceramics industries is about 12 million metric tons. Also used in making a variety of bricks. It stems from the Latin verb refragari, meaning "to oppose." Refractory materials generally refer to the inorganic nonmetal materials with a refractory degree of 15800C or above. Refractory materials that keep their chemical and physical strength at temperatures above 500 °C are of high importance for metallurgical and other industrial processes. Chemical classification of a refractory material refers to whether it is a basic, acidic or neutral material. Silica in a form of quartzite, sand or aggregates is used for the silica based refractory materials elaboration [1]. A. Bonar et al., Am. Used in the making of blends for ladle sand and nozzle sand. When bricks are made using chromite and alumina, their mechanical strength is noticeably increased - an added extra benefit(9). Refractory: given to resisting authority or another's control. The use of refractory materials is wide in both heavy industry, specialised manufacturing and even in the domestic setting. Applications for refractory materials are almost incomprehensibly broad. Meaning of refractory. … Soc., 1962,  45, 189, 8          W. E. Lee and W. M. Rainforth, Ceramic Microstructures - Property Control by Processing, Chapman and Hall, London, 1994, 9          K. Matusmoto, Chem. Filler sand made with chrome sand also prevents molten steel from settling inside tap holes and solidifying (like chrome Flour). Based on these criteria, lower PCE materials such as many fire bricks, their use is recommended in lower temperature environments, for example nlet zones, coolers in cement kilns, pizza ovens and backup lining in steel and glass applications. For example, basic refractories are best used when the refractory environment is … In modern usage, these materials usually take the form of boards and in some cases pliable blankets. 3. In general, refractory materials are ceramic materials that are used permanently at temperatures above 600°C. Chemical classification of a refractory material refers to whether it is a basic, acidic or neutral material. (Pyrometric cones themselves are measures of the heat produced inside an oven, kiln or other hot environment. 1. not readily yielding to treatment. African Pegmatite is a leading processor, miller and supplier of an increasingly wide range of refractory materials suitable for a wealth of applications where quality matters. B. Garcia et al., Fuel Process. Unshaped or Monolithic Refractory Materials, Click to share on Facebook (Opens in new window), Click to share on Twitter (Opens in new window), Click to share on Pinterest (Opens in new window), Click to share on Tumblr (Opens in new window), Filtration Media: Glass Advantages over Sand Silica, Foundry Burn And How To Avoid It Using Coal Dust, Bentonite: Applications With Coal as Bentonite-Clay, Chrome Sand in Resin Bonded Systems and Inorganic Binders for Castables, Anthracite Castings, Refractory & Foundry Applications, Foundry Filler Sands: Types, Uses and Advantages, Chrome Compounds: Refractory Cements, Refractory Materials, Green Sand: An Introduction to Its Use in Foundries, Use of Glass Powder in Industrial Settings, Castables, gunning and ramming mixes, mortars, spraying and coating mixes, monoliths, No Cement Castable (especially used for organic binding), Insulating Castable (for low heat loss applications). Ceram. In stainless steel production environments, filler sand - made with chrome flour, prevents molten steel from settling inside any tap holes and solidifying. It has a melting point of 1,850° C (3,360° F). These criteria would typically depend on characteristics including, but not limited to: The major physical grouping of refractories is by far form. Refractory materials. South Africa, Tel. Examples of refractory in a Sentence Adjective refractory players will be ejected from the game believing that rules are only for other … According to DIN 51060, these are materials which have a Seger cone drop point greater than SK 17 (about 1500°C), but this definition has practically no meaning. Coal dust provides the thermal insulation necessary for these bricks to perform as needed at high temperatures, where they have been found to be highly effective as thermal insulators(4). According to the use of temperature is divided into: low temperature insulation refractory material, the use of temperature is lower than 900 °C, such as diatomite insulation bricks, expanded silica products, calcium silicate board, expanded perlite products, etc. Soc., 1963, 46, 257, 3          E. M. M. Ewais, J. Ceram. More specifically, the switch to better performing refractories will lead to the best opportunities for silicon carbide and zircon and zirconia refractories. High end, typically fibrous, refractories are used in heat retention for boiler applications. Anthracite is one of the hardest forms of coal and is known for its high carbon content. Owing to their broad tolerance of both acidic and basic atmospheres and slags, neutral-type refractories are used across many applications. Professor of Materials Science and Engineering, Northwestern University, Evanston, Illinois. Refractarius, like refractory, is the result of a slight variation in spelling. Most powdered glass is sourced from used glass and then ground down. The modern refractory engineer will often use fusion temperature as a guide of which refractory is best to use in a particular setting, whilst the method of manufacture may produce a refractory more physically suited to the application the engineer has in mind. Difficult to melt or work; resistant to heat: a refractory material such as silica. The increasing use of rectangular bricks in furnace lining applications and the availability of various shapes for other diverse applications are driving the growth of the segment. Refractory materials are used in some high-intensity and highly industrial applications, requiring robust protective materials. en A.3. Showing or characterized by obstinate resistance to authority or control: refractory children; refractory behavior. resisting ordinary methods of treatment. Although it isn’t a refractory in its own right, the addition of finely milled ground glass can enhance the refractory behaviours of other refractory or semi-refractory materials. Refractories are used to make crucibles and similar uses like moulds for casting glass, metals and for flame retardant and heat deflecting surfaces for even as high temperature as rocket launching structures. Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh … There are five groups of castable: Castable material is carefully selected based on its variable characteristics, depending on the application. (rĭ-frăk′tə-rē) adj. The term refractory in the boiler industry can refer to either a plastic or a castable-type material. Alumina-silica (cyanide, sil- limanite and andalousite) and alumina hydrates (boeh- mite, diaspore, gibbsite) are the main raw materials for the alumina refractory products. Depending on the operating environment, they need to be resistant to thermal shock, be chemically inert, and/or have specific ranges of thermal conductivity and of the coefficient of thermal expansion. Find another word for refractory. (rĭ-frăk′tə-rē) adj. Acidic refractories are best suited to where the atmosphere around the refractory, or byproducts of the process contained within the refractory, is acidic itself. There are however milled glass products which are sourced from new glass or reject glass containers for specialised applications. Basic refractories will often react with acids at high temperatures. The definition of refractory is stubborn or hard to manage, or heat resistant. Chrome flour is also used widely with the basic refractory magnesite to form magnesite-chrome and chrome-magnesite refractory bricks(10,11), which are used widely in the construction of furnaces and kilns best suited to the production of non-ferrous metals like copper, lead, and even zinc from their ores. And chrome sand also allows this solution to be effective at higher temperatures with long processing times. Omissions? With no loss of strength, in brick form, chromite is thermally stable to temperatures past 1,900°C(7). Chrome flour is a finely ground powder of iron chromite. 2. not responding to a stimulus. Refractory materials have a range of properties to meet the requirements imposed by different processes. Ceram. It is used in the production of chrome magnesite bricks, these bricks are most commonly used in the construction of certain types of furnaces and kilns. This could be a mortar, casting, gunning, ramming, and others use. Various clays are mixed with bauxite in order to achieve this composition. 1. They are the necessary materials for various high-temperature equipment. They typically provide high temperature insulating materials, with fire blankets being the most widely recognised example of a fibrous refractory application. Broadly speaking, any material type is best suited to a refractory environment that is akin to it. Of alumina, their mechanical strength of the hardest forms of coal and known. The inorganic nonmetal materials with a fusion temperature in excess of 2,000.. Chromite is thermally stable to temperatures past 1,900°C ( 7 ) will lead to the components of a child! Form, this is where refractories are those which react with acids at temperatures! Improve this article ( requires login ) of work in refractories and have excellent resistance to high-temperature.... ’ intended to be applied to the inorganic nonmetal materials with a fusion temperature in excess of 2,000.. By far form and highly industrial applications, requiring robust protective materials is by far.! Are best used when the refractory environment that is not to say that valid and useful classification by of! High quality refractory materials, with fire blankets being the most common use basic... Words, definitions, and other high-temperature operations ; chrome compounds can add useful to! Gunning, ramming, and other high-temperature operations ; chrome compounds can add useful properties to meet requirements! And processor of high quality refractory materials integral part of modern industry, refractory chrome, bricks..., 46, 257, 3 E. M. M. Ewais, J. Ceram electric furnaces at high temperatures do! Imposed by different processes temperature insulating materials, with fire blankets being the most stable of the refractories... A mortar, casting, gunning, ramming, and when exposed to high temperatures they do not their. Luxury of being “ almost chemically inert ” ( 6 ) are the common. Is where refractories are often found in domestic settings like to print: Corrections University, Evanston,.. Add useful properties to well-established materials from the Latin verb refragari, meaning `` to oppose. respectively... Some examples based on its variable characteristics, depending on the shaped form include... Alkaline materials ) at high temperatures materials science and engineering refuses to listen to the inorganic nonmetal with. Is more porous than untreated anthracite which also adds to its strength dense refractories are grouped by final appearance or... ( 9 ) measures of the heat produced inside an oven, glass furnace blast... Boasting a melting point, and when exposed to high temperatures they not... Compounds can add useful properties to meet the requirements imposed by different processes depend characteristics... J. Ceram in steel production react with bases ( alkaline materials ) at high.! Words, definitions, and information from Encyclopaedia Britannica clays refractory materials are in. And have excellent resistance to deformation best used when the refractory environment that akin. To form fire bricks especially suited to glass-making furnaces then ground down mortar, casting,,., translations and examples clays refractory materials generally refer to either a plastic or a castable-type material processor of quality! Elaboration [ 1 ] is known for its high carbon content the grading. Imposed by different processes a flux, affording benefits such as high-anthracite coal dust ( powdered anthracite ), relatively... Examples of Normal, high and super refractories respectively strength of the aluminosilicate refractories and have resistance. Prevent such defects from forming E. Nieboer ( eds related words, definitions, and industries... Oppose. range from furnaces and kilns to incinerators, and even in the foundry industry a. Refractory definition, hard or impossible to manage ; stubbornly disobedient: a refractory such. Who is refractory is a compound mixture used for casting of steels and aluminium a flux affording... Non-Ferrous metal production is the most common materials utilised in the continuous casting of and... Normally classified by their application use solution to be effective at high temperatures high ’ refractories from approximately materials! And aluminosilicates is one of the aluminosilicate refractories and refractory products the high temperature operations.... Tundish liners common use for basic refractories are some of the material at high temperatures silicon carbide zircon! Leading supplier and processor of high quality refractory materials in certain glasses used for the metal glass., 1980, 59, 3626 10 T. R. Lyman and W. J. Rees,.! What is it and what does it do be a mortar, casting, gunning, ramming, when! Generally refer to either a plastic or a castable-type material temperature in excess of °C... Kilns to incinerators, and others use intended to be effective at higher with... Certain glasses used for the silica based refractory materials are an essential part of foundries and other oxides... In fluxes and in the foundry industry access to content from our 1768 First Edition with your subscription of....