Glossary
Glossary by alphabetic list :
You are looking for a definition of terms :
Glossary by branch :
- Minerals for Ceramics, Refractories, Abrasives & Foundry
- Performance & Filtration Minerals
- Pigments for Paper
- Materials & Monolithics
For additionnal information : webcom@imerys.com
Abrasives
substances used for wearing or polishing.
Aggregate
coarse or graded material, or any size fraction of it above an arbitrary minimum, in a refractory product. Somewhat similar to civil engineering concretes, where aggregates will be rock.
Alumina
Aluminum oxide (Al2O3).
Andalusite
a natural alumino-silicate mineral, transforming into mullite when fired. Usually contains around 60 % alumina.
Ball clay
Very fine-grained ceramic clay, chiefly mined in Devon and Dorset (UK). Its plasticity makes it an essential component in certain ceramics, especially sanitaryware and tableware.
Bold roll tiles
large format tiles used mainly on the lower pitched roofs in southern Europe. Typical examples are the “Romane” and “Meridionale” Tiles.
Bone china
a thin and translucent chifrom a body containing bone ash, china clay and Cornish stone.
Breathable film
a polyolefin film into which coated ground calcium carbonate (FilmlinkTM) is incorporated during the production process. This creates micropores that allow air to circulate without affecting the film’s watertightness.
Calcined clays / chamottes
calcined clays, usually calcined in a rotary kiln, at high temperature (1400 – 1600ºC), and which transform into mullite and glass. C-E Minerals is a world leader in calcined clays.
Calcined kaolin
kaolin modified through very high (700-1,200ºC) temperatures. Calcination improves whiteness and changes the chemistry, making the kaolin less hydrophilic and reducing electrical conductivity
Ceramic body
a blend of several ceramic raw materials, that together form the starting material used by potters to make ceramic articles.
Chemically precipitated calcium carbonate (PCC)
can be formed from the same naturally occurring limestone by exposure to controlled amounts of heat and pressure. This allows engineering of the mineral formation, giving a high degree of control over its morphology and thus its characteristics.
China clay
also known as kaolin, is a white soft plastic clay derived from the decomposition of granite or similar rock. Most kaolin is wet refined to produce a range of products to improve both physical and chemical properties to meet specific customer applications. The Group has mineral reserves in all three high-quality kaolin mining regions in the world: Cornwall, UK; Georgia, USA; and the Amazon delta in Brazil.
Chromite
Chrome ore, mined mostly in RSA. Widely used in the foundry industry for its high refractoriness.
Coating
after the paper web is completely formed and dried, coating mixtures containing kaolin, GCC, PCC, additives and binders are applied to the paper surface in a thin layer to produce coated paper. These coatings change the properties of the paper to make it glossier, more opaque and brighter.
Cordierite
synthetic product made from alumina silicate and magnesium. Cordierite is extremely heat-resistant – up to 1,200ºC - and is used to make kiln furniture and technical ceramics, among other things.
Diatomite
a silica-based mineral formed from the fossilized remains of microscopic aquatic plants. It is used as a filtration agent to clarify beer, fruit juices, some food products and wine, and produce pharmaceuticals or and chemicals. It is also used as a mineral filler, mainly in paints, and as an anti-adhesiveblock for plasticspolymer films.
Earthenware
white ceramic, not translucent, not particularly durable, baked at about 1,150º. It is made essentially of clays to which are added feldspath and silica. It is a porous product that requires glazing.
Engineered pigments
this refers to kaolin and GCC products where the particle size distribution and shape has been modified (naturally or synthetically) to be substantially different from traditional products
Engobes
clay-type raw materials that are projected onto tiles before baking. They enhance tile color and surface.
Feldspar
natural mineral used for the vitrification of ceramic bodies in porcelain and earthenware manufacturing.
Fillers
in the paper industry, fillers are added at the start of the paper making process and become trapped in the fibrous structure of the paper web as it forms. Kaolin, GCC and PCC fillers impart unique properties to paper, improving notably appearance and printability. Fillers are also used in a veriety of industrial applications such as paints, plastics,
rubbers, etc.Flat tile
A flat tile is a roofing component made up of a clay slab with a batten hooking system (stubs or plates) on its underside and one or more fastening holes at its head.
Flat tiles are usually rectangular in shape but some models have rounded or V-shaped lower parts.Fused alumina, brown
fused in electric arc furnaces. Main raw material is a special (abrasive) grade of bauxite. During the fusion other oxides included in the bauxite (Fe, Ti, Si) are reduced to the desired level. Production can be described as fusing and refining process of bauxite.
Fused alumina, special
by alloying with other elements (e.g. TiO2 and/or Cr2O3) during the fusion of alumina special fused aluminum oxides like the Pink or Ruby type are produced.
Fused alumina, white
fused in electric arc furnaces. During fusion of abrasive grade alumina the physics of aluminum oxide are changed (higher density and different crystal structure and size).
Glaze
surface-covering product made of the same materials as ceramic bodies. Enamel enhances and embellishes porcelain. It enhances resistance and the colors of earthenware and stoneware.
Ground calcium carbonate (GCC)
originates from the sedimentation of seashells and other marine life, which formed deep bands of chalk and limestone. Exposure to intense heat and pressure as continents shifted, recrystalised some of these into marble as seen in the renowned mountains of Carrara in Italy. Grinding these minerals gives products with a precise shape and size, characterized by their high brightness. Imerys has a global platform for the production of GCC with reserves in Europe, North America and South America, Asia.
Gunning
Method for applying refractory products via wet or dry projection.
Half-round tiles
These roofing components look like conical gutters.
They are used as undertiles when laid with their curved face downward or overtiles when the curved side faces upward.Halloysite
very white, transluscent clay.
High-performance graphite
Natural or synthetic crystallized carbon used for applications including electrical batteries, friction products (e.g.brake pads) and technical lubricants.
High-Performance Graphites Engineering
Friction Materials: the rapid development in automotive applications over the past few years has created a growing demand for high quality friction materials. Besides of a high level of energy adsorption, the main requirement that a brake lining has to meet is high braking efficiency within a wide range of temperature. Other factors such as lifetime, absence of noise as well as comfort aspects have also to be taken into consideration. These requirements are fulfilled by means of high performance brake pads, in which carbon powders such as graphite and coke play a key role.
Carbon Brushes: the “carbon part world” is a unique industry that has to comply with many and contradictory requirements such as: electrical and thermal conductivity, lubricity and hardness, mechanical strength and resistance to corrosion. These targets can be achieved only by very well defined high performance raw materials of outstanding consistency such as graphite and coke. Plastics: on account of their precisely defined characteristics and consistency in quality, TIMCAL carbon additives are used in large number of well known plastics compounds. Depending on the specification, the following properties can be defined or modified: both thermal and electrical properties, chemical properties, processability and specific mechanical properties. Powder Metallurgy: graphite powders play an important role in powder metallurgy. Depending on the segment within the powder metallurgy industry, graphite powders have to meet different, particular requirements. In the production of hard metals, as an example, the purity of the graphite is of primary importance, whereas in the production of structural components dimensional stability, compactibility and lubricity are additional key factors. Diamond: diamonds are forever! As it is well known two big families of Diamonds are present in the market. Natural Diamonds extract from the mines and Synthetic Diamonds. Synthetic Diamonds can be used in many industrials fields, such as cutting tools, drilling and laser applications. For all of these applications, Diamond purity is the key factor. This requirement is fulfilled by means of very high purity raw materials, in which both synthetic and natural purified graphite powders represents the optimum starting material.High-Performance Graphites Mobile Energy
Alcaline Batteries: non-rechargeable high-power batteries. Their power is being continuously increased through a technical development using sophisticated graphite materials with high electrical conductivity. These batteries are used, for instance, in portable CD-players, remote-controlled toys etc
Lithium-ion Batteries: lithium-based high-tech rechargeable batteries. Their safe functioning is ensured by a special graphite electrode. They are used in mobile telephones, portable computers, video cameras etc. Fuel Cells: continuously fuelled system converting chemical energy into electricity. This principle allows very high efficiency and a low environmental impact. Still in development, these cells need new high-technology graphite materials. Their use may be stationary (domestic energy supply) or mobile (cars, telecommunication).High-Performance Graphites Refractories and Foils
Refractories: graphite is added to basic refractories to improve properties such as resistance to molten metal or slag penetration and thermal shock resistance. Typical applications for graphite containing refractories are linings for blast furnaces, electric arc furnaces and steel laddles.
Foils: by intercalating acid between graphite layers and then heating rapidly the created “salt”, exfoliated or expanded graphite is produced. This expanded graphite can then be pressed or rolled into flexible sheets or foils which are then used for gasket making. These foils retain their properties over a wide range of temperatures.Hip
the meeting line of two inclined roof surfaces which meet at the external angle.
Injection
Method for applying very fluid refractories (slurry) under pressure so that the product fills empty spaces or cavities.
Interlocking tiles
roof tiles that fit as a result of special channels located at the head and side of the tiles. This type of tiles reduces the weight of the roof compared with conventional tiles (Roman or flat).
Kaolin
Also known as china clay, is a white soft plastic clay derived from the decomposition of granite or similar rock. Most kaolin is wet refined to produce a range of products to improve both physical and chemical properties to meet specific customer applications. The Group has mineral reserves in all three high-quality kaolin mining regions in the world: Cornwall, UK; Georgia, USA; and the Amazon delta in Brazil.
Kiln furniture
Shaped parts made from refractory materials (cordierite, mullite or silicon carbide) that must provide good resistance to mechanical and heat shock and be as light as possible to save energy during firing.
Large format flat tiles
these interlocking tiles are found typically on the large pitched and smooth slope roofs in central and northern France, whenever with a flat surface
Large format tiles
interlocking tiles, with a coverage of 10 to 15 tiles per m2.
Magnesite
an important component of basic refractories. Usually obtained by calcining magnesium carbonate. Can also be fused.
Monolithic refractories
made of a natural or synthetic mineral raw materials, including chamottes, andalusite, mullite, bauxite, tabular or fuse dalumina, spinel (“acid” monolithic”), magnesite, dolomite and chromite (“basic” monolithics), to which are added binders, e.g. refractory cement, clay and additives.Monolithic refractories are fitted by casting, plugging or projection.
Mullite
the main component of acid refractories = highly refractory alumino-silicate, not found in nature except in traces, but obtained from firing various raw materials: clays, andalusite, kyanite, etc.
Perlite
a volcanic rock containing 2-5% water which, when heated quickly, turns to steam, dilating its rock matrix to up to 20 times its initial volume. The result is a lightweight material with a high contact surface. It is used to filter beverages. It also has significant outlets in construction (ceiling slabsjoint compound) and horticulture (off-ground cultivationhydroponics).
Porcelain
very white ceramic, durable and translucent, fired at around 1,400ºC, used in tableware. It is made essentially of china clay, to which are added feldspar and quartz.
Pouring
Method for applying concrete by gravitational flow. Depending on the concrete’s rheology, pouring can involve vibrators, rodding or self-pouring.
Prestressed concrete products
Prestressed concrete products, mainly joists, are used for floor construction. Filler blocks are placed between each joist. These can be made from a variety of materials, including clay, which is the division’s specialty. In addition to joist, the range also includes structural beams, calculated for each use, which allows for quicker installation at the construction site.
Ramming
Method for applying plastics using a rammer (a type of automatic power hammer)
Refractories
materials that resist high temperatures. Depending on the application, they cab also bear heavy weights or resist.
Refractory grade bauxite
a natural mineral association, alumina rich, calcined at high temperature. Main producer: China, also Guyana, Brazil.
Silicon carbide
is a synthetic product obtained by running an electric current through a mixture of silica (sand) and petroleum coke (Acheson process). SiC is formed by heat then ground into various grades. A high temperature application product (1,350 - 1,700ºC), SiC offers high mechanical resistance; it is also an excellent heat conductor and resists oxidation well. It therefore increases furnace capacity by reducing product thickness, allows fast baking methods and provides product lifespan. In short, it enables customers to improve productivity. It is notably used in kiln furniture for porcelain.
Slags
in metallurgical processes, non-metallic impurities or additives (fluxes) concentrate in slags, usually above the liquid metal. Their temperature and chemical composition often make them highly agressive vis a vis the refractories.
Small format tiles
interlocking tiles, with a coverage of 17 to 20 tiles per m2.
Spray-dried bodies
granulated ceramic bodies made by atomising slurry into a drying tower.
Stoneware
ceramic used in tiles, tableware and sanitaryware. This product is intermediate between earthenware and porcelain. Its resistance to warping at high temperature allows large pieces to be fired (very useful in sanitaryware). Its components are the same as those of earthenware, except for certain specific clays. Stoneware may be porous or vitrous.
Tabular alumina
a high quality alumina, requiring a special manufacturing process.
Vermiculite
Hydrated mica that expands greatly when heated, this mineral is used in particular for insulation and horticulture
Vitreous
any ceramic body fired to a sufficiently high temperature that is no longer porous or able to absorb water.
White or brown fused alumina (Fused aluminium oxide, fused bauxite)
products obtained by fusing alumina (white) or bauxite (brown) in an electric arc furnace. During fusion, the physics of aluminum oxide are changed (higher density and different crystal structure and size).
White pigments
kaolin, GCC and PCC are used in the paper industry as a filler – to give a smooth texture and whiteness to the sheet and to help it rapidly and uniformly absorb ink during the printing process – and as a coating product to give the paper a smooth, bright and glossy surface for high quality printing. Kaolin and GCC are also used as high performance extenders in many types of paint, where they improve opacity, scrub resistance and as a partial replacement for expensive prime pigments.
Zircon
Zircon is sold in different forms such as zircon sand or flour. Fused zircon is obtained by melting zircon sand in an electric arc furnace and takes the form of precisely calibrated grains and powders with sizes ranging from several millimeters down to less than a micron. Its unique properties mean it is used as a high value-added raw material in a wide range of applications, particularly on the refractories, friction and technical ceramics markets.