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WO1992000246A1 - Procede de production de particules de spinelle de magnesium a partir de produits residuels et particules produites par ce procede - Google Patents

Procede de production de particules de spinelle de magnesium a partir de produits residuels et particules produites par ce procede Download PDF

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Publication number
WO1992000246A1
WO1992000246A1 PCT/CA1991/000220 CA9100220W WO9200246A1 WO 1992000246 A1 WO1992000246 A1 WO 1992000246A1 CA 9100220 W CA9100220 W CA 9100220W WO 9200246 A1 WO9200246 A1 WO 9200246A1
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WO
WIPO (PCT)
Prior art keywords
process according
particles
alumina
magnesium
waste material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CA1991/000220
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English (en)
Inventor
Sadashiv Kashinath Nadkarni
Luc Parent
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rio Tinto Alcan International Ltd
Original Assignee
Alcan International Ltd Canada
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Alcan International Ltd Canada filed Critical Alcan International Ltd Canada
Publication of WO1992000246A1 publication Critical patent/WO1992000246A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
    • C01F7/16—Preparation of alkaline-earth metal aluminates or magnesium aluminates; Aluminium oxide or hydroxide therefrom
    • C01F7/162—Magnesium aluminates
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
    • C22C32/0089—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with other, not previously mentioned inorganic compounds as the main non-metallic constituent, e.g. sulfides, glass

Definitions

  • This invention relates to a process for producing particles of magnesium spinel and to the particles so- produced.
  • Metal matrix composite materials are of great interest nowadays because they combine relative lightness of weight with high strength and can therefore be used for new applications in many industries.
  • the composites comprise a metal matrix normally reinforced with ceramic material in the form of generally spherical particles, platelets or whiskers.
  • Silicon carbide is a material that is often suggested as a suitable reinforcement, but it has the disadvantage that it reacts with molten aluminum or aluminum-containing alloys, which results in a weakening of the reinforcing effect for aluminum-based composites.
  • Magnesium spinel (magnesium aluminate, MgAl 2 0 A ) is a material that is resistant to attack by molten aluminum and its alloys but it is currently manufactured by fusing commercial grade alumina and magnesia together. This makes it quite expensive and therefore unsuitable for use on a commercial scale as a reinforcing material for metal matrix composites.
  • alumina-containing materials are well known, such as clay and bauxite, they cannot be used for the formation of magnesium spinel without extensive extraction procedures because they contain too many impurities.
  • Yet another object of the invention is to provide a process for producing magnesium spinel particles suitable for metal matrix reinforcement.
  • a process for producing particles comprising magnesium spinel suitable for reinforcing metal matrix composites comprises: mixing particles of a waste material containing alumina or an alumina precursor in substantial amounts with particles of magnesium oxide or a magnesium oxide precursor to produce a mixture, calcining the mixture at a temperature suitable to form magnesium spinel, optionally comminuting particles of the spinel having sizes larger than 50 ⁇ m to particles of smaller size, and collecting particles of said spinel having sizes in the range of 5-50 ⁇ m.
  • the invention also relates to the magnesium spinel particles so-produced.
  • waste material as used in the present invention, we mean any material that is generally discarded rather than being sold for commercial use, or which is rejected for use in most commercial processes. Such materials are generally by-products of commercial processes or sub-standard products of such processes. The important requirements of such materials are that they provide an inexpensive source of alumina, contain a large proportion of alumina or alumina precursor available for the formation of magnesium spinel and contain only impurities which do not adversely affect the process of the present invention.
  • Waste products from the aluminum industry containing at least 30% by weight of A1 2 0 3 or a precursor thereof and containing less than about 0.2% by weight of other impurities that are not volatile under the reaction conditions of the process of the invention are especially preferred.
  • Figure 1 of the accompanying drawings is a scanning electron micrograph of a product produced according to the process of the present invention (see Example 2) .
  • waste products of high alumina content can be used as one of the starting materials for the formation of magnesium spinel so that the cost of production of the spinel can be reduced.
  • These materials are generally waste alumina- containing products from the aluminum industry.
  • some of the waste products contain an amount of MgO, or precursor thereof, so that less of this other starting material of the process has to be added prior to the calcination step.
  • a particularly preferred waste product for use as a source of alumina in the present invention is aluminum dross residue.
  • Dross is a material which forms on the surface of molten aluminum or aluminum alloys during remelting and metal holding and handling operations when the molten metal is in contact with a reactive atmosphere, such as air.
  • Dross normally consists of aluminum oxide and aluminum nitride, as well as oxides and nitrides of other metals, e.g. magnesium, which may have been present in the metal.
  • Dross from magnesium-containing aluminum alloys may therefore already contain a part of the magnesium oxide required for the process of the invention, or even an amount of the desired final product, magnesium spinel.
  • Dross normally also contains a certain amount of free metal, most of which is removed for re-use to leave a dross residue, which has in the past been viewed as a waste product.
  • Dross residues differ not only according to the composition of the metal on which the dross was formed but also according to the process employed for the removal of the free metal.
  • a traditional process involves heating and tumbling the dross in the presence of a molten salt bath in order to remelt the metallic fraction and to cause the resulting small molten metal droplets to coalesce and form an easily-separable molten metal pool. While the process is quite efficient for extracting the metal, the residual salt cake forms a large proportion of the dross residue.
  • dross residue produced in this manner is to be used in the present invention, it should be treated to remove the salt fraction prior to use in the process. This can be done for example by washing the dross residue with water to dissolve the salt, separating the undissolved solid from the salt solution and then drying the remaining dross residue.
  • the large proportion of A1N can be converted to aluminum oxide (alumina) prior to use in the present invention by contacting the dross residue with water or steam at a temperature of up to about 300 ⁇ C.
  • This converts the nitride to the hydroxide and ammonia and subsequently leads to the dehydration of the hydroxide to form the oxide.
  • this prior conversion of AlN to A1 2 0 3 is not generally necessary prior to the process of the present invention because it has been found that the nitride reacts directly during the calcination step with available oxygen to produce the desired magnesium spinel and thus acts as an alumina precursor.
  • dross residues resulting from yet other metal removal procedures can also be used in the present invention, e.g. dross residue resulting from the electric arc treatment of dross or the procedure described by Montagna in U.S. Patent No. 3,999,980 issued on December 28, 1976 (the disclosure of which is incorporated herein by reference) . Even dross which has not been treated to remove most of the free metal content may be used as a starting material for the present invention provided the metal content is not too high.
  • the aluminum content in the dross is low, it is possible to grind the dross to the desired particle size. However, if the aluminum content is high, the dross is usually in the form of an agglomerate of large pieces and it is not easy to grind to a smaller particle size, so the excess aluminum must be removed, prior to use, to form a dross residue.
  • ESP dust is very fine undercalcined alumina separated from the exhaust gases of alumina calciner ⁇ . Typically more than 90% by weight of the material is less than 44 microns in size. It consists of a mixture of calcined, partially calcined and uncalcined particles, consequently its loss on ignition can vary between 1 and 35% by weight. It is further characterized by containing small amounts of oxides of other metals, such as sodium oxide (typically 0.3 to 0.7% by weight or higher). The material has very limited commercial or industrial value, and is normally disposed of as waste material or transformed by physical or chemical treatments into more useful products.
  • ESP dust is very fine undercalcined alumina separated from the exhaust gases of alumina calciner ⁇ . Typically more than 90% by weight of the material is less than 44 microns in size. It consists of a mixture of calcined, partially calcined and uncalcined particles, consequently its loss on ignition can vary between 1 and 35% by weight. It is further characterized by containing small amounts
  • the magnesium oxide used as the other starting material in the process of the invention may itself be a waste product, but is normally a commercial product available in fine powder form. If desired, precursors such as magnesium carbonate may be employed instead.
  • the magnesium spinel particles produced by the process of the invention will only be suitable for use as metal matrix reinforcements if the particles have sizes in the range of 5-50 ⁇ m, more preferably 10-30 ⁇ m, and most preferably 10-15 ⁇ m. In those cases where the reaction does not produce particles in this size range without intervention, steps must be taken to modify the process. This can be done in a number of ways as outlined in the following.
  • the starting materials are preferably first comminuted to a size of about 20 ⁇ or smaller. This can be achieved by crushing or grinding the starting materials, e.g. in a ball mill or the like.
  • This preliminary size reduction step not only helps to ensure that the product of the process will be of the desired particle size, but also makes it possible to thoroughly mix the starting materials together as a dry powder mixture prior to calcination so that the starting materials come into intimate contact suitable for complete reaction. Moreover, mixtures of fine powders take less time to react during the calcination step and thus make the process more economic.
  • dross residue When used as a source of alumina, it is usually in the form of large particles which are preferably ground to a size of -325 Tyler mesh prior to use. ESP dust is already of submicron size and commercial MgO is also generally already of -325 Tyler mesh size.
  • the starting materials of the desired small particle size are mixed in a V-blender or other mixing apparatus for a period of at least one hour to achieve the desired intimate mixture.
  • the particles produced by the process are larger than the stated range, e.g. if the product is in the form of large fused lumps, the product can be comminuted and classified to obtain a suitable product.
  • the product includes particles having a range of sizes, including sizes in the desired range
  • screening to obtain the desired fraction can be carried out with subsequent milling and screening of any larger size fractions.
  • particles larger than the desired range can be reduced in size by comminution as indicated above, particles smaller than the desired range generally have to be discarded.
  • the particles produced without intervention do tend to be too small, often about 2-5 ⁇ m, or contain a substantial fraction within this size range. This is usually the case when lower calcination temperatures and shorter calcination times are employed.
  • materials which act as particle size modifiers can be added to the reactants to promote the formation of larger particles.
  • Suitable particle size modifiers include oxides of other metals, e.g.
  • mineralizers such as fluorides (e.g. MgF 2 , CaF 2 , Na 3 AlF 6 , NaF, A1F 3 , Na 2 SiF 6 and H 2 SiF 6 ) , in quantities sufficient to promote crystal growth.
  • fluorides e.g. MgF 2 , CaF 2 , Na 3 AlF 6 , NaF, A1F 3 , Na 2 SiF 6 and H 2 SiF 6
  • the particle size modifiers are generally used in amounts in the range of 1-2% by weight of the reaction mixture and are generally added to the starting materials in fine powder form (preferably less than 20 ⁇ m) prior to the thorough mixing of the starting materials.
  • the calcination step of the process of the invention usually, but not necessarily, requires a temperature of at least 1450 ⁇ C, a reaction time in the range of 1 to 3 hours 5 and is normally carried out under an atmosphere of air, but other non-reactive atmospheres (such as oxygen or argon) could be employed, if desired. Larger particles tend to be formed at higher calcination temperatures, and temperatures in the range of 1650°C + 50"C often produce 0 the most desirable particles.
  • the starting materials are generally used in relative quantities which provide approximately the stoichiometrical amounts of alumina and MgO required for the production of alumina spinel during the calcination 5 step, although this is not absolutely essential since some contamination of the product with the starting materials can be tolerated.
  • the relative amounts of the starting materials vary with the alumina content of the waste material used as the alumina source and the 0 magnesium content (if any) of the alumina-containing waste material.
  • the ratio of the dust to MgO is generally about 2.5:1.0 by weight.
  • dross a ratio of dross residue to MgO of 3.5:1.0 by weight has proven satisfactory, although this ratio would
  • compositions were prepared, each containing 100 g of plasma dross residue and 29 g of MgO plus a different particle growth promoter, namely the following:
  • the mixtures were heated in air at 1450°C for two hours for a first series of tests and identical mixtures were then heated in air at 1650"C for the same period of time for a second series of tests.
  • Particles of suitable size were formed in all cases and larger particles were obtained at the higher temperature.
  • the best growth agents were, in increasing order of effectiveness, B 2 0 3 , Si0 2 , Na 3 AlF 6 and the mixture of CaF 2 with Na 3 AlF 6 .
  • the A1N present in the dross residue had been oxidized completely. Scanning electron microscopy showed the product to be in the form of particles having a size of 2-
  • the magnesium spinel particles of size 5-50 ⁇ produced according to the present invention can be used as reinforcements for metal matrix composites, particularly when the metal phase is aluminum or an aluminum alloy.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

Abstract

Un procédé de production de particules de spinelle de magnésium (aluminate de magnésium) s'adressant au renforcement de composites de matrices métalliques. Le procédé comprend le mélange d'un matériau résiduel contenant de l'oxyde d'aluminium ou un précurseur comme le résidu de mâchefer, la poussière d'ESP ou l'oxyde d'aluminium de transition ou encrassé, provenant d'installations utilisant le procédé de Bayer ou d'usines d'électrolyse à sels fondus, avec de l'oxyde de magnésium, ou un précurseur pour réaliser un mélange, la calcination du mélange à une température capable de produire du spinelle de magnésium (normalement entre 1450 et 1650 °C) et la récupération des particules de spinelle de magnésium dont la dimension se situe entre 5 et 50 νm, si nécessaire, après avoir réduit des particules plus grandes à des dimensions correspondant à la norme souhaitée. De préférence, on peut ajouter des promoteurs de croissance aux matériaux de départ, par exemple des oxydes et des fluorures métalliques généralement utilisés en quantités d'environ 1-2 % en poids. Les particules économiques ainsi produites possèdent une dimension appropriée au renforcement d'une matrice métallique et ne réagissent pratiquement pas à l'aluminium fondu ni aux alliages d'aluminium.
PCT/CA1991/000220 1990-06-28 1991-06-18 Procede de production de particules de spinelle de magnesium a partir de produits residuels et particules produites par ce procede Ceased WO1992000246A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US54600390A 1990-06-28 1990-06-28
US546,003 1990-06-28

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WO1992000246A1 true WO1992000246A1 (fr) 1992-01-09

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5514361A (en) * 1994-04-29 1996-05-07 Aluminum Company Of America Method for making a synthetic meixnerite product
WO2002079090A1 (fr) * 2001-03-29 2002-10-10 Commonwealth Scientific And Industrial Research Organisation Procede de production de spinelle synthetique
RU2275331C2 (ru) * 2004-01-27 2006-04-27 Геннадий Гильфанович Галимов ГИДРАТИРОВАННЫЙ ГИДРОКСОАЛЮМИНАТ ФОРМУЛЫ Mg6Al2(OH)18·4H2O И СПОСОБ ЕГО ПОЛУЧЕНИЯ
RU2359913C1 (ru) * 2008-02-08 2009-06-27 Геннадий Гильфанович Галимов Вещество на основе гидроксоалюмината магния, содержащее соосажденный гидроксид алюминия, и способ его получения
RU2392225C2 (ru) * 2008-07-04 2010-06-20 Геннадий Гильфанович Галимов Композиция из гидроксолюмината магния и гидроксида алюминия и способ ее получения
CN114906865A (zh) * 2022-05-11 2022-08-16 西安近代化学研究所 一种制备MgAl2O4尖晶石的方法及MgAl2O4尖晶石

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2252797A1 (de) * 1971-10-29 1973-05-10 Nippon Light Metal Res Labor Aluminiumhaltiges, verschleissfestes material
JPS49134710A (fr) * 1973-04-27 1974-12-25
FR2286119A1 (fr) * 1974-09-26 1976-04-23 Quigley Co Procede de production de spinelle d'aluminate de magnesium
US3955969A (en) * 1974-06-26 1976-05-11 R.C.M. Corporation Process for the production and use of activated alumina
US4743299A (en) * 1986-03-12 1988-05-10 Olin Corporation Cermet substrate with spinel adhesion component

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2252797A1 (de) * 1971-10-29 1973-05-10 Nippon Light Metal Res Labor Aluminiumhaltiges, verschleissfestes material
JPS49134710A (fr) * 1973-04-27 1974-12-25
US3955969A (en) * 1974-06-26 1976-05-11 R.C.M. Corporation Process for the production and use of activated alumina
FR2286119A1 (fr) * 1974-09-26 1976-04-23 Quigley Co Procede de production de spinelle d'aluminate de magnesium
US4743299A (en) * 1986-03-12 1988-05-10 Olin Corporation Cermet substrate with spinel adhesion component

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, vol. 74, no. 20, May 17, 1971, Columbus, Ohio, US; abstract no. 101168 U, A. KIELSKI 'Synthesys of spinel. ' page 58 ; see abstract *
CHEMICAL ABSTRACTS, vol. 83, no. 10, September 8, 1975, Columbus, Ohio, US; abstract no. 83948 C, H. TASHIRO 'Barium aluminate refractories from waste water sludge. ' page 310 ; see abstract & JP,A,74 134 710 (TASHIRO) December 25, 1974 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5514361A (en) * 1994-04-29 1996-05-07 Aluminum Company Of America Method for making a synthetic meixnerite product
WO2002079090A1 (fr) * 2001-03-29 2002-10-10 Commonwealth Scientific And Industrial Research Organisation Procede de production de spinelle synthetique
RU2275331C2 (ru) * 2004-01-27 2006-04-27 Геннадий Гильфанович Галимов ГИДРАТИРОВАННЫЙ ГИДРОКСОАЛЮМИНАТ ФОРМУЛЫ Mg6Al2(OH)18·4H2O И СПОСОБ ЕГО ПОЛУЧЕНИЯ
RU2359913C1 (ru) * 2008-02-08 2009-06-27 Геннадий Гильфанович Галимов Вещество на основе гидроксоалюмината магния, содержащее соосажденный гидроксид алюминия, и способ его получения
RU2392225C2 (ru) * 2008-07-04 2010-06-20 Геннадий Гильфанович Галимов Композиция из гидроксолюмината магния и гидроксида алюминия и способ ее получения
CN114906865A (zh) * 2022-05-11 2022-08-16 西安近代化学研究所 一种制备MgAl2O4尖晶石的方法及MgAl2O4尖晶石
CN114906865B (zh) * 2022-05-11 2023-07-18 西安近代化学研究所 一种制备MgAl2O4尖晶石的方法及MgAl2O4尖晶石

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