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Magnesia glossary
| A |
ABBRASIVE ABSORPTION Penetration of a substance into the body of another. Absorption properties of magnesium oxide are important in neutralisation applications e.g. ACETIC ACID TEST -Caustic Magnesia Activity (CMA) Substance which is capable of binding acids. The basic character of magnesia causes it to be a widely used acid acceptor. This term describes the central magnesia property. ACID BINDING -> Acid Acceptor Common term for the reactive capability of magnesium oxide. Its correlation with ACTIVITY INDEX Former measure for -> Activity of magnesium oxide, expressed by its ADSORPTION Binding of gases or liquids at or on (also inner) surface of a solid only by surface forces and not by chemical bonds. AGEING Test criterion especially for rubber compounds determining the change in properties (hardness, tensile strength, elongation at break) relative to the time of storing or stress under defined conditions (DIN 53508). Ageing properties are highly dependent on the degree of cross-linking which is determined by the curing process. Magnesium oxides with selected properties may positively influence curing. AGGLOMERATES Assemblage of powdered particles rigidly joined together. Precipitated magnesia in particular is made up of agglomerates in the form of very small crystallites measuring as little as only a few microns. Undesired agglomerates are formed by humidity and carbon dioxide from the atmosphere if magnesia is handled incorrectly. AGRICULTURE Large application area for magnesia, particularly as additive for fertilisers and animal nutrition, as well as for plant protection against acid rain. Common term for the alkaline reaction of caustic magnesium oxides. It is determined by acid titration or by neutralisation tests. Non-crystalline solid material. Magnesia would appear to be amorphous, especially in cryptocrystalline modifications, through X-ray diffraction reveals the existence of crystalline structures. Substance counteracts excess production of stomach acid Substances (additives) which maintain the free-flowing properties of powders. Magnesium hydroxide carbonates are widely used for anti-caking purposes, e.g. in table salt. The mass of powdered or granulated materials (mainly g/l) loosely filled in a measuring cylinder (s. DIN 53912). The mass of powdered or granulated materials (mainly g/l) compacted in a tapping volumeter (s. DIN 53194)APPARENT VOLUME Volume of a defined mass of powder, free-flowingly filled. The A.V. is a feature listed in pharmacopoeias, e.g. for pharmaceutical magnesia grades. ASH Residue formed when e.g. magnesia paste is ignited (at 950 °C). A. represents the (ignited free) content of magnesium oxide (DIN 53658). Impact of humidity and carbon dioxide on magnesium oxide which lowers quality. ATOMIC ADSORPTION SPECTOMETRY (AAS) Spectrometric method of analysis for determining the quantity of a wide range of elements, particularly metals in low concentrations. AAS may be used to determine, e.g., traces of cadmium, copper, chromium, cobalt, nickel, lead, mercury, Arsenicic in magnesia. |
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BALL MILL Mill consisting of a horizontal cylindrical vessel in which a substance is ground by rotation with steel or ceramic balls. Used also for grinding magnesite. BASIFICATION -> Tanning -> Specific surface Area BIG BAGS Packaging form using large bags of approx. 1 m³ volume to pack, e.g., distinct magnesia types. BMC = Bulk Moulding Compound. Polyester resin compounds made from unsaturated polyester resins and textile glass. BMC is moulded to moulded thermosetting parts. Magnesia is used for thickening (control of viscosity) of BMC -> LUVATOL BOWL MILL Type of mill for micronising minerals using a pendulum-like milling tool. Widely used to grind magnesite. Abbreviation for British Pharmacopoeia. Lining of friction elements for brakes and clutches containing magnesia. BRINE Salt solutions, product of -> Leaching BROMOBUTYL RUBBER Elastomers containing bromine. Application area of magnesium oxide. Viscosity data obtained by measuring with a Brookfield Viscometer having a rotating measuring device. One of its applications is to determine the viscosity of polyester resins for -> SMC Magnesium containing mineral. Chemistry: Magnesium hydroxide Mg(OH)2 B. S. Abbreviation for British Standards Mixtures of substances limiting change in pH value when acids or alkalis are added. Magnesium compounds may be constituent of a buffer mixture if a high pH-value has to be avoided. -> Neutralisation. Moderate to strong heating of solid substances to separate crystal water and for thermal decomposition. Burning is used, e.g., to produce magnesium oxide from magnesium carbonate or magnesium hydroxide. Calcination is the more common term for B. of Magnesia. -> Burning Temperature Choice of burning temperature influences BURNT MAGNESITE |
| C |
CALCINATION -> Burning CALCINED MAGNESIA Common term for Common term for magnesium oxide produced from C A Q Abbreviation for computer aided quality control. Common term for caustic (low, light) calcined magnesium oxide. Shows alkaline reaction. CAUSTIC MAGNESIA ACTIVITY (CMA) Reaction test for magnesium oxide using acetic acid. Sintered material, porous or tight produced also by use of magnesia. High purity magnesia types offer interesting perspectives for new applications in engineering ceramics. Polymerisation product of chlorinated butadiene showing specific properties additional to those similar to natural rubber. Important application area for active magnesium oxide, also in paste form to prevent scorching. CHROME TANNING -> Tanning Reaction test for magnesium oxide using citric acid, especially for magnesium oxide for -> Transformer Steel. CLUTCH LININGS COATED MAGNESIA Surface treated magnesia, e.g., with stearic acid for special purposes Instrument used for the precise measurement of intensity of a colour. Used to determine iron and manganese when analysing magnesia. A special colorimeter is used to determine the whiteness of powders. -> Leukometer COMPLEXOMETRY Widely use analytical method applied, e.g. for volumetric determination of calcium and magnesium in magnesia, sometimes also for other elements. COMPRESSION SET Test method for elastomers to determine the residual deformation after defined compression (DIN 53517). C. S. depends on the degree of cross-linking of the elastomer which, in turn, is influenced by the curing process. Since magnesium oxide impacts curing together with other components C. S. is used as one criterion to select the most appropriate grade of magnesium oxide. Content of magnesia in MgO expressed as percentage is defined in various ways. Very often the data relates to the ignited material, in other cases the content is given without correction for the loss on ignition. CORROSION CONTROL -> Fuel Oil CRUCIBLE MATERIAL Magnesia grades for producing sintered crucibles in metallurgy. CRYPTO CRYSTALLINE Virtually -> Amorphous Materials containing very small crystallites. The crystalline structure can only be proven by x-ray diffraction. CRYSTALLINE A solid in which the atoms or molecules are arranged in a regular lattice |
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Abbreviation for Deutsches Arzneibuch, the German pharmacopoeia. Magnesia calcined above 1,600 °C under vast loss of activity. DENSITY Mass of unit volume of a substance expressed in g/cm³, often also in g/ml. Density of magnesia is generally given as DIFFERENTIAL THERMAL ANALYSIS (DTA) DIN Symbol for "DIN Deutsches Institut für Normung", the German standards authority. Original abbreviation for "Deutsche Industrie Norm". For magnesia the standards DIN 53912 (Apparent Density Loose), DIN 53194 (Apparent Density Tapped), and DIN 53580 (Wet Screen Residue) are of importance. DOLOMITE Magnesium containing mineral, Chemistry MgCO3 · CaCO3. |
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-> Modulus ELASTOMERS Natural or synthetic polymers with elastic properties after cross-linking. Magnesium oxide is used mainly in polychloroprene rubber, halobutyl rubber, chlorosulphonated polyethylene and fluor rubber. ELECTRIC ARC FURNACE Electric furnace in which the heat for melting magnesium oxide (approx. 3,000 °C) is produced by an electric arc between carbon electrodes, or between a carbon electrode and the furnace charge. ELECTRO FUSED MAGNESIA ELONGATION AT BREAK Elongation of material (normally expressed as percentage of its original length) on breaking. This mechanical property of cured elastomers is determined by the extent of cross-linking. Since the curing process is influenced by the added agents (e.g. magnesium oxide) it is essential that these are carefully selected. For magnesium oxide activity and particle size distribution are of special importance. Abbreviation for European Pharmacopoeia. EPSOM SALT Magnesium sulphate, Chemistry: MgSO4 · 7H2O. |
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Preparation of material with additives or fillers which prevent or retard spreading of flames in case of fire. Special magnesium hydroxide types are used for this application. They are applied as functional fillers in polymers in high concentrations FLUOR RUBBER Elastic high polymers formed by copolymerisation of vinylidene fluoride and chlorofluoroethylene (CFM-type) of copolymerisation or terpolymerisation with other unsaturated fluorohydrocarbons (FKM-type). Application area of magnesium oxide with controlled medium activity. FOODSTUFFS Magnesia is added to a large number of food preparations. German law allows the use of magnesium carbonate on a general scale while magnesium oxide and magnesium hydroxide are limited to certain foodstuff applications. FORSTERITE A silicate of magnesium, Mg2SiO4. With defined electrical insulation properties it represents an important layer on transformer steel sheets. The layer is formed by the reaction of magnesium oxide with the silicone of the steel during annealing. FRICTION LININGS FRITS Porous material formed by sintering inorganic powders such as magnesium oxide and carbonate. Hydrocarbon mixture used as fuel. The sulphur contained in the mixture produces acidic gases on combustion which may be neutralised by magnesium oxide to minimise corrosion. Magnesia produced by fusion in an electrical arc furnace at a temperature of approx. 3,000°C. |
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Regulation of the German Ministry of Employment and Social Services concerning protection of workers and consumers from hazardous material. GLASS INDUSTRY Magnesia is used in the manufacture of a number of special types of glass as part of the glass charge. Form of magnesia with dust-free properties formed by binding with appropriate agent. Suitable therefore for pneumatic pumping and automatic dosing. "Generally Recognised As Safe". Term of F.D.A. (US Food and Drug Administration). Analytical method used for determination of a substance by |
| H |
HEAVY METALS General term of metals with a density of (normally) more than 4.6 g/cm3. Usually taken to mean lead, mercury, cadmium, zinc and copper, although there is no reason for this limited choice. For pharmaceutical qualities summarising tests are used. The results are given as lead. Magnesium oxide with large surface area -> Activity HUMIDITY Water adsorbed on material which may be removed by drying under a temperature normally slightly above 100°C. HYDRATISATION Absorption of and reaction with water. For magnesium oxide it is a feature of the residual reaction capability after calcination. HYDROCHLORIC ACID INSOLUBLES Quality criterion for magnesia giving information on content of impurities, such as silica or gypsum. As gypsum occurs rarely in magnesia the H.A.I. generally concern silica. HYDRO MAGNESITE Magnesium containing mineral. |
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INVESTIGATION METHODS Laboratory methods used to characterise properties of materials. A distinction could be made between physical and chemical investigation methods. Application-oriented methods are applied in addition for magnesia, e.g., test for Value indicating the I.S.O. Abbreviation for International Organisation for Standardisation. I.S.O. standards, e.g. for screens are also applied to magnesia. |
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JET MILL High efficiency fluidised bed mill. The kinetic energy of opposed gas jets is used for the super fine grinding of dry powders down to particle sizes in the micron and submicron range. |
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KIESERITE Magnesium containing mineral. |
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Analytical method to determine Traditional application area for magnesia. Wet extraction of, e.g., magnesium containing minerals by dissolving in hydrochloric acid as preparation for -> Pyrohydrolysis Old term used for an instrument to determine "whiteness". Weight-loss by drying, normally 2 - 4 hours at 105 - 110°C. L O I Abbreviation for -> Loss on Ignition but also for Limiting Oxygen Index, the oxygen content of an atmosphere necessary to combust a material, e.g., a polymer. Weight loss of, e.g., magnesium oxide when ignited, normally 2 hours at 950°C. It is caused by adsorbed and absorbed water and carbon dioxides (DIN 53 568). LUVOCORR Lehmann & Voss & Co. trademark for selected magnesia types to be applied in -> Fuel Oil to reduce corrosion. Lehmann & Voss & Co. trademark for highly active magnesium oxide pastes for application in polychloroprene mixtures. Supplied in portioned rolls weighing 1 kg. Lehmann & Voss & Co. trademark for pastes containing magnesium oxide or magnesium hydroxide and calcium hydroxide. Used to control thickening of |
| M |
MAGCARLUV Lehmann & Voss & Co. trademark for magnesium carbonates. MAGNESIA General term for magnesium oxide, magnesium hydroxide and magnesium carbonate. Depending on origin and production procedure it is divided into -> Caustic Latin synonym for magnesium hydroxide carbonate. MAGNESIA BLOCKS Press-formed magnesium hydroxide carbonate. Used to bind hand perspiration in athletics and for cosmetic purposes. Flooring made from -> Sorel Cement and sawdust. Formed and sintered magnesium oxide. Latin synonym for magnesium oxide. Magnesium containing mineral. Chemistry: In the magnesia business the term M. is often used for calcined magnesite whilst the mineral is called raw (crude) magnesite. Extraction process for wood to produce pulp using magnesium bisulphite solution for leaching. The leaching solution is prepared by reaction of sulphur dioxide with selected magnesium oxide types in an aqueous slurry. Magnesium compound. Primary MgCO3 -> Magnesite The term is also commonly used for the various magnesium hydroxide carbonates produced by carbon dioxide precipitation from magnesium containing solutions. Watersoluble magnesium compound. When water is evaporated, it forms magnesium carbonate. Commercially it is not available. Magnesium compound. -> Magnesium Carbonate Magnesium compound. Chemistry: MgO -> Calcined Magnesia Lehmann & Voss & Co. trademark for a co-dispersion of an active magnesium oxide and zinc oxide for Chloropren rubber. Supplied in portioned rolls weighing 1 kg. Lehmann & Voss & Co. trademark for magnesium oxide powder. MAK-Wert Maximale Arbeitsplatz Konzentration. = Maximum Workplace Concentration of hazardous materials. The general dust limit of 6 mg/m3 applies also to magnesia fine dust. MICRONIZING Milling of powder to very low particle sizes. Technique very important to magnesia to achieve particle sizes showing optimal dispersion capability. MILK REPLACERS Special animal feedstuff containing substantial amounts of magnesium oxide to supplement nutrition of, e.g., calves during weaning. MINERAL FEEDSTUFFS Feedstuff preparation containing essential minerals of which magnesium oxide is an integral additive. Application of magnesium oxide requires careful selection regarding bio-available magnesium content and particle size. Force required to achieve defined modification of shape (stretching, compression, bending). Of particular interest in rubber technology is the This is the force needed to stretch a test material with a cross-section of 1 cm2 by, e.g., 100 % (modulus 100). The value is given in N/cm2 (previously kg / cm2), i.e., based on the cross-section of the (unstretched) sample. Details found under DIN 53 504. Modulus is used, like other data for material testing of cured products, to assess quality of rubber mixture components, such as magnesia. Shear-disc plastometer to determine plasticity of viscosity of elastomers and mixtures and their scorching properties. It measures the shear resistance of a standardised test-piece rotating in the test chamber filled with the elastomer being tested. The result is given in degrees Mooney. 1° Mooney corresponds to 8.64 g s m. Test is carried out mostly for 4 minutes at 100°C (DIN 53 523 and 53 524). Often also called Mooney Viscometer. Important characteristic for rubber mixtures. Elapsed time is measured when plasticity rises from 5 units to 35 units above minimum at a certain temperature. The instrument used to measure this is the -> Mooney Plastometer. M.S.T. characterises storing stability and processing conditions of rubber mixtures (DIN 53 524) and thus quality properties of additives like magnesia. MULTIPLE-HEARTH ROASTER Vertical kiln, subdivided into hearths, typically used for -> Burning and roasting of materials, e.g. -> Raw Magnesite |
| N |
Magnesium containing mineral. Chemistry: Magnesium carbonate The reaction of an acid and a base with the formation of a salt. Magnesia, mainly magnesium oxide, is used in various applications to bind acids (buffer). Abbreviation for National Formulary. Originally covered only defined qualitative standards for pharmaceutical ingredients. Since 1975 NF is published together with Following this, monographs of both compendia were harmonised so dual listing of single substances is avoided. Since USP XX/NF XV magnesia is only listed in USP. USP XXI/NF XVI is in force since 1985. |
| O |
OIL ABSORPTION Amount of a defined oil which can be soaked up by a powder substance, e.g. magnesia, without draining out again. Physically this phenomenon is an -> Adsorption but the term O.A. is usual. Functional additives, often -> Surfactants for lubricants. Sulphonates containing magnesium are produced from magnesia. OPTICAL SORTING Sorting process using different colour or similar optical properties of materials to separate them from each other: Important for refining of raw magnesite. OXYChlorideE CEMENTS Setting test using magnesium sulphate (Epsom Salt) to investigate certain qualities of magnesium oxide for use in specific reactions, e.g. production of -> Oil Additives |
| P |
Portion of particles with certain sizes in a powder matrix. For magnesia very important quality feature in many applications. -> Laser Diffraction Viscose to highly viscose pre-dispersed magnesia preparations with excellent processing properties enabling safer and more convenient application of magnesium oxide in polychloroprene rubber and polyesters. -> BMC Manufacturing process to produce magnesium hydroxide carbonate ( especially with low apparent density) from magnesia limestone or dolomite. Magnesium containing mineral. Compendia of regulations for the quality of drugs and ingredients and their investigation. Pharmaceutical magnesia qualities are mostly defined according to Science of pharmaceutics. -> Laxative PHENOLIC RESINS PHLOGISTON THEORY Theory prevalent in the 17th century which understood exothermal phenomena, such as combustion and corrosion, as being caused by a single agent called phlogiston. According to this theory incombustible substances contain no phlogiston whilst those containing phlogiston burn the more readily proportional to the amount of this agent contained therein. Disproved at the end of the 18th century by Lavoisier. Analytical methods based on measuring light absorption or emission. Manual method or sorting when raw minerals and ones are mined. POLYCHLOROPRENE Polymers produced by polycondensation of polyhydric alcohol with polybasic acids. Liquid unsaturated polyesters react with magnesium oxide and magnesium hydroxide under thickening. This property is used to control viscosity, e.g. in -> BMC High molecular compounds often also called plastics. Magnesia is used in polymers as a stabiliser (acid acceptor) or to impart -> Flame Retardancy POWDERS BLENDS To obtain tailor-made properties, such as certain apparent density or activity, distinct magnesia qualities are produced by special blending process. PRECIPITATED MAGNESIA Magnesia produced by Chemical reaction between substances giving a product insoluble in the reaction medium. Precipitation of the magnesium hydroxide from the seawater in one example. PRILLED MAGNESIA Agglomerated magnesia, similar to PULP Main constituent of wood. Produced by leaching off the lignin substances. As leaching agent -> Magnesium Bisulphite produced by reaction of sulphur dioxide with aqueous slurries of magnesium oxide is most widely used. PURITY Purity is often indicated by percentage content of MgO and that impurities. Results are mainly given on ignited basis, e.g. in pharmacopoeias or on "as-is" basis, i.e. without correction of ignition loss. Process to produce metal oxides, e.g., magnesium oxide , by thermal decomposition of aqueous solutions containing the metal Chloridees. |
| R |
Common term for natural. -> Activity The high melting point (2800°C) and the heat resistance ( 1700°C in the reducing and 2300 °C in oxidising atmosphere) of magnesium oxide make it suitable for the production of refractories. -> Magnesia Clinker Instrument to determine rheological properties e.g. viscosity. Used to analyse thickening property of polyester resins with the magnesium oxide or magnesium hydroxide: special type of R. is used to determine state of cure of rubber mixtures. ROTARY KILN Rotating kiln, slightly inclined from the horizontal axis, used for |
| S |
First step in the curing of rubber mixtures, mostly undesired. Quantity of substances remaining on the screen after sieving. -> Sieving , Screening Magnesia produced from seawater as magnesium source by the Method of extracting magnesia from seawater. Seawater contains approx. 1300 ppm magnesium. Magnesium containing mineral. Term previously used for the trivalent oxides Fe2O3 and Al2O3, precipitated together as hydroxides by ammonia during quantitative magnesia analysis. Property of magnesium oxides to form a tough and stone-like material when reacting exothermally with other magnesium compounds such as magnesium Chloridee or magnesium sulphate in aqueous slurry. S.C. is determined by test revealing setting time and temperature Purification of sewage to allow for harmless feed into main drainage channels or for direct recycling. Due to the soft alkaline properties of magnesia, it may be used as a neutralising agent in S.T. Vertical kiln, typically used for Separation and classification of material into different particle Wet screening according to DIN 53 580 is usual for magnesia. Crystalline magnesium oxide with uniformly patterned crystal lattice. Used in optics and electronics. Magnesium oxide burnt at high temperature (dead-burnt) SMC = Sheet Moulding Compound. Polyester resin compound made from polyester resin and textile glass. Magnesium oxide and hydroxide is used for thickening of SMC. -> Luvatol SOLUBILITY Magnesia is practically insoluble in water. Setting product of magnesium oxide and aqueous magnesium Chloridee solution. Powder characteristics, mostly determined by -> B.E.T. Method with -> Activity -> Burning Temperature and -> Iodine Adsorption is evident. Instrument for measuring light emission or absorption for qualitative detection or quantitative determination of coloured or light emitting or absorbing substances. SURFACE ACTIVE SUBSTANCES, SURFACTANS Substances which, e.g., lower surface tension of liquids. They are constituents of detergents and lubricants. Magnesia produced by |
| T |
Processing of animal skins with chemicals to produce leather. Chrome tanning uses selected magnesium oxide to self-adjust and control the pH value during the process (Self-adjusting basification agent). Force necessary to break a standardised test-piece expanded under defined conditions. The value is given relative to the cross-section of the test-piece. Widely occurring disease in animals caused by magnesium deficiency. Measures for the capability of homogenous material to conduct heat. Fused magnesium oxides are used for insulating heating elements due to their very high thermal conductivity together with electrical resistance. Term for analytical methods to determine properties of material in relation to temperature (decomposition, phase transformation). Cross-linked high polymers made from resin capable of being hardened. On heating thermal breakdown occurs without the plastic melting. Magnesia is used as a buffer in phenolic resin types for compression moulding. Sheets made from silicon steel coated with a layer of -> Forsterite (Mg2SiO4) possessing defined electrical insulation properties. The layer is formed by the reaction of magnesium oxide with the steel silicon. Term defining the light transmittance of a substance. Special magnesium carbonate types are capable of being applied in transparent rubber mixtures. |
| U |
United States Pharmacopoeia. -> NF |
| V |
Application area for magnesium oxide and hydroxide. -> BMC -> SMC to control the viscosity of unsaturated polyester resins and their thickening properties. -> Rheometer VITAMIN PREPARATIONS Drugs, mostly OTC-type, also doped with minerals, (e.g., magnesium as magnesia) to simultaneously compensate for vitamin and mineral deficiencies. Thermal and / or chemical treatment of liquid or plastic rubber mixtures to impart elastic properties. The polymer chains are, therefore, generally cross-linked with sulphur to create a three-dimensional network. Magnesium oxide prevents |
| W |
WASSERGEFÄHRDUNGSKLASSEN (WGK) Scheme created by the Federal Republic of Germany to classify substances according to their potential hazard to water. Using the criteria of self-classification magnesia is given WGK 0, the most harmless class. Only highly active magnesium oxide types should be classified WGK 1 due to the degree of their alkalinity. Procedure to micronise organic and inorganic substances, e.g. magnesia. The substance for milling is slurred in an appropriate liquid (mostly water) and then micronised. Percentage of substance remaining on the screen after wet screening. WHG Wasserhaushaltsgesetz. German law dealing with regulations concerning water conservation and prevention of water pollution. It also contains the scheme of -> Wassergefährdungsklassen WHITENESS Measure to define colour of white and whitish powders. Pure magnesium oxide is used for calibration. -> Colorimeter WOOD-BURNT MAGNESITE To produce caustic magnesite low on sulphate, raw magnesite is burnt with wood. |
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