EP0000981B1 - Matière réfractaire plastique à base de minerai de chrome - Google Patents

Matière réfractaire plastique à base de minerai de chrome Download PDF

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Publication number
EP0000981B1
EP0000981B1 EP78300228A EP78300228A EP0000981B1 EP 0000981 B1 EP0000981 B1 EP 0000981B1 EP 78300228 A EP78300228 A EP 78300228A EP 78300228 A EP78300228 A EP 78300228A EP 0000981 B1 EP0000981 B1 EP 0000981B1
Authority
EP
European Patent Office
Prior art keywords
hectorite
chrome ore
plastic
composition according
refractory composition
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.)
Expired
Application number
EP78300228A
Other languages
German (de)
English (en)
Other versions
EP0000981A1 (fr
Inventor
Nicholas Cassens
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.)
Kaiser Aluminum and Chemical Corp
Original Assignee
Kaiser Aluminum and Chemical Corp
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 Kaiser Aluminum and Chemical Corp filed Critical Kaiser Aluminum and Chemical Corp
Publication of EP0000981A1 publication Critical patent/EP0000981A1/fr
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Publication of EP0000981B1 publication Critical patent/EP0000981B1/fr
Expired legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/03—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on magnesium oxide, calcium oxide or oxide mixtures derived from dolomite
    • C04B35/04—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on magnesium oxide, calcium oxide or oxide mixtures derived from dolomite based on magnesium oxide
    • C04B35/043—Refractories from grain sized mixtures
    • C04B35/047—Refractories from grain sized mixtures containing chromium oxide or chrome ore
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/24—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing alkyl, ammonium or metal silicates; containing silica sols
    • C04B28/26—Silicates of the alkali metals

Definitions

  • This invention relates to plastic chrome ore refractory compositions.
  • the invention is concerned with refractory compositions comprising 85% to 95% size-graded chrome ore, 1% to 5% of alkali metal silicate binder, 0% to 5% of a plasticizer other than hectorite and sufficient water to form a plastic mass, all percentages being by weight and based on the total dry weight of the ingredients.
  • the amount of alkali metal silicate binder stated is calculated as sodium silicate.
  • Plastic chrome ores are well-known in the refractories industry and are described, for example, in U.S. Patent Specifications 2,792,311 and 2,965,505 and in British Patent Specification 1,002,486.
  • plastic chrome ore refractory compositions have the disadvantage of tending to bloat or swell under conditions of rapid heating.
  • the compositions are made up with water so as to be in a form suitable for application or other treatment in preparation for use and setting of the compositions essentially involves driving of water from the composition; temperatures at or a little above the boiling point of water are commonly used for this purpose, therefore, but the tendency to bloat can be very troublesome.
  • the compositions disclosed in British Patent Specification 1,002,486 are proposed in an attempt to solve this problem. Specifically, this specification discloses the addition of flock or asbestos in minor amounts to these compositions, in order to prevent such swelling or bloating.
  • the present invention is directed to the solution of this problem.
  • the invention is based upon the discovery that any undesirable tendency to swell or bloat under conditions of rapid heating, such as apply when moisture is being driven off from the composition, is minimized or even eliminated if the refractory composition includes 0.5% to 5% of hectorite, the percentage amount being by weight and based upon the total dry weight of the ingredients of the composition.
  • the chrome ore used can be any of such materials, either natural or synthetic, well-known in this art. Size-graded chrome ore is used, in order to achieve good density upon placement of the refractory compositions, as will be well understood.
  • the chrome ore may all be less than 9.5 mm in diameter and size-graded so that roughly one-third is greater than 2 mm in diameter, roughly one-third is less than 2 mm in diameter and greater than 0.15 mm in diameter and roughly one-third is less than 0.15 mm in diameter.
  • This size grading means that all the chrome ore passes a 9.5 mm (% inch) mesh screen, roughly one-third is retained on a 9-mesh screen, one-third is retained on a 100-mesh screen and the remaining one-third passes a 100-mesh screen.
  • Hectorite is a hydrous silicate of magnesium and lithium, sometimes containing fluorine, and occurs naturally near Hector, California, United States of America. It has also been produced synthetically and either form can be used in carrying out this invention. However, the natural material is preferred, particularly a refined grade of the natural material. Hectorite is a well-known material which has been used in many compositions, including refractory gun mixes, for example as disclosed in U.S. Patent Specification 2,407,725. It has also been used as a coating on refractory material, for example chrome ore. This is disclosed for instance in U.S.
  • Patent Specification 2,406,910 which is concerned with the well-known expansion of chrome ore refractory products at high temperature when they absorb iron oxide, either from a hot furnace atmosphere or from a molten slag. This troublesome expansion is also sometimes referred to as "bloating", but it is a very different phenomenon from the one which the present invention is concerned with.
  • the solution to the problem of the expansion of the chrome ore is to place a coating of hectorite on the chrome ore particles. At high temperatures, such as gives rise to the troublesome expansion, for example about 1200°C, this coating reacts with the particles, imparting a protective coating to them.
  • the action of the hectorite in the present invention takes place at much lower temperatures, for example temperatures slightly above 100°C, at which the compositions are dried.
  • temperatures slightly above 100°C at which the compositions are dried.
  • the swelling or bloating which the present invention alleviates takes place during drying of the refractory compositions, and is totally unrelated to the well-known expansion due to chemical action, which takes place in chrome ore refractories at elevated temperatures.
  • the binder material may be any of the many well-known varieties of sodium silicate. It is believed that it is the swelling action of the sodium silicate binder upon drying which leads to bloating of conventional plastic chrome compositions and that such bloating tendency is higher when a sodium silicate of relatively high silica content is used. Accordingly, this invention is particularly useful with such high silica sodium silicates.
  • the sodium silicate can be added either dry or in liquid form; the latter form has proved to be particularly convenient. However, in which ever form (dry or liquid solution) the sodium silicate is added, the percentage amounts given in the specification and claims refer to the amount of dry material added. In other words, if a solution is added, the percent of sodium silicate added is the amount of that material in the solution (i.e., the amount obtained upon drying the solution).
  • Other, equivalent alkali metal silicates, for example lithium silicate can be used.
  • plasticizer While a plasticizer is not essential, it has been found to impart improved workability to the plastic chrome ore and the inclusion of a plasticizer is therefore preferred.
  • the plasticizer can be any of the many well-known materials of this type, for example, it can be an organic material, e.g. methyl cellulose.
  • a clay, particularly a plastic kaolin type of clay has proved particularly useful in making compositions according to this invention.
  • clay means a hydrous aluminosilicate type of mineral, for example of the kaolinite type, which exhibits lubricity and plasticity when admixed with water. See, for example, the definition of "clay” in Ceramic Glossary (American Ceramic Society, 1963).
  • the term “clay” is particularly to be distinguished from the hectorite used in compositions according to the present invention, which is a magnesium silicate mineral.
  • the sized chrome ore and other ingredients are mixed together, for example in a Muller mixer, and sufficient water is then added to form a plastic mass.
  • the precise amount of water to be added depends upon the types and amounts and sizing of the materials used, including the form in which the sodium silicate or other binder is added, but will generally range from 1% to 5% by weight, based on the total weight of the composition.
  • the composition can also contain other ingredients without departing from the scope of this invention.
  • it can contain a sequestering agent (for example, ethylene diamine tetra-acetic acid), which prevents premature reaction, and consequent setting of the mix, between the sodium silicate binder and any stray magnesia which may have got into the composition.
  • a sequestering agent for example, ethylene diamine tetra-acetic acid
  • the expression "based on the total dry weight of the ingredients” means that the weight percentages given are based upon the amount of material which would be found in the composition after it had been dried; that is to say, after any water, whether added to form the plastic mass, added as part of the alkali metal silicate binder solution or added with any sequestering agent solution, had been removed.
  • a plastic chrome ore refractory composition according to this invention was made from 88.3 parts of sized Transvaal chrome ore, 7.83 parts of RU grade sodium silicate (an aqueous solution of sodium silicate made by Philadelphia Quartz Co. having 13.8% Na 2 0, 33.2% Si0 2 and a Si0 2 :Na 2 0 ratio of 2.4:1), 2.62 parts of Hamilton II clay (a plastic kaolin), 0.25 part of Versene (Trade Mark- an ethylene diamine tetra-acetic acid sequestering agent) and 1 part of Baroid Macaloid, a refined hectorite ore.
  • RU grade sodium silicate an aqueous solution of sodium silicate made by Philadelphia Quartz Co. having 13.8% Na 2 0, 33.2% Si0 2 and a Si0 2 :Na 2 0 ratio of 2.4:1
  • Hamilton II clay a plastic kaolin
  • Versene Trade Mark- an ethylene diamine tetra-acetic acid sequestering agent
  • the Transvaal chrome ore was sized so that all was less than 9.5 mm in diameter (i.e., all passed a % inch mesh screen) and 28.1 parts were greater than 2 mm in diameter (i.e., were retained on a 9-mesh screen), 28.1 parts were smaller than 2 mm and larger than 0.15 mm (i.e., retained on a 100-mesh screen), and 32.1 parts were smaller than 0.15 mm.
  • the chrome ore over 2 mm in size had the following typical chemical analysis (ignited basis): 11.1% MgO, 0.4% CaO, 8.2% Si0 2 , 14.5% AI 2 0 3 , 39.7% Cr 2 0 3 and 26.1% Fe 2 0 3 ; and that under 2 mm in size, a beneficiated ore, the following typical analysis: 44.1% Cr 2 0 3 , 28.7% Fe 2 0 3 , 15.1% AI 2 Og, 9.7% MgO, 0.2% CaO and 2.2% Si0 2 .
  • the Hamilton clay and the hectorite were both substantially all less than 44 microns in size (i.e., both all passed a 325-mesh screen) and the Versene (Trade Mark) was in the form of an aqueous solution.
  • This composition was tested for bloating by hand ramming it into a can 10.5 cm in diameter by 12 cm high using a 20 mm (% in) diameter steel rod. The excess material was cut off with the edge of a trowel and the top surface smoothed. Four vent holes were made in the exposed surface with a 3 mm (1 ⁇ 8 in) diameter welding rod to a depth of 5 cm (2 in). After the material had dried for 48 hours at room temperature and had then been dried in an oven for 16 hours at 120°C (250 °F), the height of the specimen above the rim of the can was measured and found to be 11.5 mm (0.46 in). The material was also stored in plastic bags for a total of 16 weeks, after which time it still remained plastic.
  • This composition can be compared with another composition made in the same way except that, in place of the hectorite, 1 part of Volclay, a plastic bentonite clay, was used, and 1.5 parts of water were used. Although this comparison composition remained plastic after storage for 12 weeks, in the bloat test it showed an increased height of 23.5 mm (0.92 in), an unacceptably high amount.
  • compositions were made using the following additives in place of the hectorite or Volclay bentonite: alumina dust collector fines, perlite, expanded vermiculite, both chopped and ball milled aluminosilicate glass fibres, cattle hair, volatilized silica, kyanite, rice hull ash, mica, wollastonite, pyrophyllite, fibrous talc, diatomaceous earth and waste material from rug manufacture.
  • Many of these comparison compositions failed to maintain their plasticity during storage, becoming set in a matter of a week or two. Others, although they did not set up prematurely, showed bloating of from 20 to 44 mm (0.78 to 1.73 in), all unacceptably high.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Ceramic Products (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Claims (8)

1. Composition réfractaire de minerai de chrome plastique, comprenant 85 à 95% de minerai de chrome classé,1 à 5% de silicate de métal alcalin comme liant, 0 à 5% d'un plastifiant autre que l'hectorite et suffisamment d'eau pour former une masse plastique, ladite composition étant caractérisée en ce qu'elle contient également 0,5à 5% d'hectorite, tous les pourcentages étant en poids, par rapport au poids total à sec des ingrédients.
2. Composition réfractaire selon la revendication 1, caractérisée en ce que l'hectorite est une hectorite naturelle.
3. Composition réfractaire selon la revendication 2, caractérisée en ce que l'hectorite naturelle est une hectorite raffinée.
4. Composition réfractaire selon la revendication 1, 2 ou 3, caractérisée en ce qu'elle contient 0,1 à 5% d'un plastifiant.
5. Composition réfractaire selon la revendication 4, caractérisée en ce qu'elle contient 1 à 5% d'argile comme plastifiant.
6. Composition réfractaire selon la revendication 5, caractérisée en ce que l'argile est du type kaolin plastique.
7. Composition réfractaire selon l'une quelconque des revendications précédentes, caractérisée en ce que le silicate de sodium liant est ajouté sous forme d'une solution liquide.
8. Composition réfractaire selon l'une quelconque des revendications précédentes, caractérisée en ce que le minerai de chrome est du type Transvaal.
EP78300228A 1977-08-25 1978-08-01 Matière réfractaire plastique à base de minerai de chrome Expired EP0000981B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US82764277A 1977-08-25 1977-08-25
US827642 1977-08-25
US05/900,540 US4166748A (en) 1977-08-25 1978-04-27 Plastic chrome ore
US900540 1978-04-27

Publications (2)

Publication Number Publication Date
EP0000981A1 EP0000981A1 (fr) 1979-03-07
EP0000981B1 true EP0000981B1 (fr) 1981-03-11

Family

ID=27125116

Family Applications (1)

Application Number Title Priority Date Filing Date
EP78300228A Expired EP0000981B1 (fr) 1977-08-25 1978-08-01 Matière réfractaire plastique à base de minerai de chrome

Country Status (7)

Country Link
US (1) US4166748A (fr)
EP (1) EP0000981B1 (fr)
JP (1) JPS5443912A (fr)
AU (1) AU518632B2 (fr)
CA (1) CA1098134A (fr)
DE (1) DE2860522D1 (fr)
IT (1) IT1098408B (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4244744A (en) * 1979-08-06 1981-01-13 Kaiser Aluminum & Chemical Corporation Refractory gun mix
US5268031A (en) * 1989-03-10 1993-12-07 Premier Refractories And Chemicals Inc. Pumpable ceramic fiber composition
US5073281A (en) * 1989-05-08 1991-12-17 Paules John R Pelletized rice hull ash and bentonite clay insulation
JPH07308538A (ja) * 1994-03-24 1995-11-28 Japan Pionics Co Ltd 有害ガスの浄化剤
DE10122263C2 (de) * 2001-05-08 2003-04-03 Schott Glas Optische Gläser und ihre Verwendung

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA553759A (fr) * 1958-03-04 Davies Ben Melanges de foulement de chrome plastique
US2407725A (en) * 1946-09-17 Refractory liking of metallurgical
DE677322C (de) * 1935-06-04 1939-06-23 Victor Moritz Goldschmidt Dr Verfahren zur Herstellung feuerfester Baustoffe
US2406910A (en) * 1943-01-06 1946-09-03 Basic Refractories Inc Treatment of refractory materials
FR1321817A (fr) * 1962-05-04 1963-03-22 Perfectionnements apportés aux mélanges réfractaires
US3208862A (en) * 1964-02-12 1965-09-28 Harbison Walker Refractories Mortar
US3297458A (en) * 1964-06-05 1967-01-10 E J Lavino & Co Plastic chrome ore
GB1069968A (en) * 1965-09-03 1967-05-24 Harbison Walker Refractorles C Mortar

Also Published As

Publication number Publication date
EP0000981A1 (fr) 1979-03-07
IT7827062A0 (it) 1978-08-25
US4166748A (en) 1979-09-04
IT1098408B (it) 1985-09-07
JPS5443912A (en) 1979-04-06
DE2860522D1 (en) 1981-04-09
CA1098134A (fr) 1981-03-24
AU3885978A (en) 1980-02-21
AU518632B2 (en) 1981-10-08

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