FR2628098A1 - REFRACTORY MASSES CONTAINING MAGNESIUM OXIDE - Google Patents

Abstract

The present invention relates to refractory masses containing magnesium oxide, in particular tamping masses, containing calcined magnesite and / or calcined dolomite as the main refractory material, as well as possibly other usual constituents, and 2 8% by weight, calculated on the total composition, of a temporary binder system containing a drying oil. The refractory masses according to the present invention are characterized in that the binder system consists of: 30 to 50% by weight of a drying oil; 30 to 50% by weight of an unsaturated fatty acid; 5 to 20% by weight of a boron compound; 5 to 20% by weight of a thermosetting resin; the total sum of the individual components of the binder system being 100% by weight. The refractory masses exhibit excellent compressibility and excellent tensile strength after drying treatment at 280 degree (s) C.

Description

ó) FRENCH REPUBLIC () N of publication 2 628 098 (to be used only

  for the NATIONAL INSTITUTE reproduction orders

OF INDUSTRIAL PROPERTY

  (OF INDUSTRIAL PROPERTY of national registration 89 02576 PARIS Int CI4: C 04B 35/66, 35/04; C 01 F 5/02; C 01 B

31/04, 31/08.

@ APPLICATION FOR PATENT OF INVENTION A1

  () Filing date: February 28, 1989. () Claimant (s): Company known as: DIDIERWERKE AC: -

OF.

  Priority: DE, March 1, 1988, No. P 38 06 563.0.

  (Inventor (s) Hartmut Hlawatschek, Jürgen Zimmer.

  4_ Date of the public availability of the

  application: BOPI "Patents" No. 36 of 8 September 1989.

  (References to other national documents

(Holder (s)

  (Attorney (s) Office D.A. Casalonga-Josse.

  (Refractory masses containing magnesium oxide.

  (The present invention relates to refractory masses containing magnesium oxide, particularly

  damer containing calcined magnesite and / or dolorite

  calcined as the main refractory material, as well as

  possibly other usual constituents, and 2 to 8% by weight, calculated with respect to the total composition, of a system

  temporary binder containing a drying oil.

  The refractory masses according to the present invention are characterized in that the binder system consists of 50% by weight of a drying oil; at 50% by weight of an unsaturated fatty acid; 20% by weight of a boron compound; at 20% by weight of a thermosetting resin: 00 the sum total of the individual components of the thermosetting system;

 binder being 100% by weight.

  O Refractory masses have excellent compres-

  sibility and excellent breaking strength after a

drying at 280 C.

  The present invention relates to refractory masses containing magnesium oxide, in particular to gassing masses containing calcined magnesite and / or calcined dolomite as the main refractory material, as well as possibly other customary constituents, and 2 to 8% by weight, based on the total composition, of a temporary binder system containing a drying oil DE-PS 27 47 636 already described. dolomite which comprise as binder linseed oil and a dry inorganic binder, and optionally materials including paper flour and / or other carbonaceous materials, DE-AS 24 24 936 furthermore discloses Casting weights containing as binder linseed oil and a thermosetting resin DE-AS 28 22 653 describes refractory masses which contain as binder a mixture of a phenol-resol resin and tall oil. We know also have basic masses, which contain pitch as the main binder component, see DE-AS 12 74 489 The object of the present invention is the preparation of refractory masses

  containing magnesium oxide which. instead of pitch, tar or bitumen.

  contain other binders less harmful to the environment, namely binders which do not emit harmful gases, for example benzopyrans, when the mass is subjected to a high temperature, these masses having to present a good

compressibility.

  Surprisingly, it has been discovered that use of a binder system is necessary.

  which comprises both drying oils and unsaturated fatty acids, a boron compound and a thermosetting resin, refractory masses can be obtained which, when used, that is to say when they are subjected to high temperatures, almost no harmful substances or gases to

  the environment, and yet have high compressibility.

- '2628098

  To achieve this objective, the invention provides refractory masses containing magnesium oxide, of the type mentioned, which are characterized in that the binder system consists of 50% by weight of a drying oil 30 to 30% by weight. 50% by weight of an unsaturated fatty acid at 20% by weight of a boron compound at 20% by weight of a thermosetting resin, the total sum of the individual components of the binder system being 100% by weight. According to a preferred embodiment, the refractory masses according to the invention contain as other constituent. I to 8% by weight. calculates, based on the total composition, graphite black smoke and / or coke. the use of

  flake graphite and / or petroleum coke being particularly preferred.

  In the refractory masses containing magnesium oxide according to the invention, it is used. as the main refractory material. calcined magnesite and / or calcined dolomite with appropriate particle size. The particle size distribution corresponds to the usual values, for example. the following granulometric distributions can be used 0 to 0.6 mm 40% 0.6 to 1.5 mm 15%

1.5 to 6 mm 45%.

  The maximum dimension of the grains can also be limited here to values of 3 mm or 4 mm, the range indicated above then corresponding to a

  grain size of 1.5 to 3 mm, or 1.5 to 4 mm, respectively.

  As other usual constituents, the refractory masses according to the invention may contain, as described above, graphite, carbon black and / or coke, in a finely divided form, flake graphite and / or coke being particularly preferred. preferred. These additives, graphite, carbon black and / or coke, are advantageously used when it is necessary to obtain refractory masses having particular characteristics, for example better

  resistance to slag corrosion or infiltration by slag.

  In the refractory masses according to the invention, a binder system is used

  which consists of a total of four constituents.

  The first constituent. which is present in the binder system in a proportion of 30 to 50% by weight. is a drying oil Among the drying oils, one counts as well the drying oils proper as the

  so-called semi-drying oils. or cooked oils. as for example the standolie.

  Examples include linseed oil. soybean oil. rapeseed oil and standole. These drying oils are described in more detail in Ullmans Encyclopadie des technischen Chemie, 3rd edition (1966). The second component, which is present in a proportion of 30 to 50% by weight relative to the total binder system. is an unsaturated fatty acid Examples of such fatty acids are oleic acid. linoleic acid and linolenic acid. however, multiple unsaturated fatty acids may also be used. In the case where these unsaturated fatty acids are not liquid they can also be used in a mixture with other unsaturated fatty acids. or they can be dissolved in an organic solvent. for example a mineral oil or an alcohol such as methanol or ethanol or in benzene or chloroform The third constituent of the binder system is a boron compound. As borate compound, it is possible to use both the borates and the boric acid but also boron trifluoride adducts (adducts of BF3). The boron compound is used in the binder system in a proportion of 5 to 20% by weight, calculated as B203 as the fourth component. the binder system comprises 5 to 20% by weight of a thermosetting resin, the resole resins and the novolac resins being particularly preferred. However, it is also possible to use resins

  furans or thermosetting melamine resins.

  The invention will be better understood using the examples below.

Examples 1 to i

  Calcined dolomite, having the particle size distribution indicated in the Table below, is mixed with carbon black and carbon black.

  flake graphite, as well as solid boric acid, in a blender.

  To this homogeneous mixture are added in each case per 100 parts by weight, the other constituents of the binder system, listed in the table below, and a homogeneous mass is prepared. The mixture is mixed in a Hobart mixer for minutes, and then the masses are subjected. compressibility tests and

  resistance to hot compression.

  To determine the compressibility. a slightly oil-filled cylindrical mold with an inner diameter of 50 mm and a height of 140 mm is filled without filling with 275 g of ready-to-use mass. Then the cylindrical punch is applied to the material to be tested and the mass is compacted in four strokes. The height of the specimen after these four strokes is determined

and designated H4.

  Six more strokes are then applied, and the height of the specimen is again determined, this height being designated H10. The results of the tests are calculated using the following formula H4 - Hi0 x 1I0 H4 These measurements are carried out in each case. in three samples The resistance to hot pressure is determined on samples that have been held for 15, 30 or 45 minutes in a drying device. at 280 ° C The hot samples are tested by means of a press to determine the KDF value (cold compressive strength). these items being compressed

  with a constant charging speed (10 + 01 N / Imm2 s) until breaking.

  The composition of the refractory masses and the measurements made on these masses are collated in the following Table:

Board

  Example I 2 3 4 5 Dolomito 3-6 mmn (parts by weight) calcined 0.63-1 mmn 30 30 40 25 20 <0.63mm It 30 30 20 30 40 Black smoke "II 1 1 Graphite on flakes 1 1 1 1 1 Standols.2, 5 2,5 2,5 2.5 2,5 Oleic Acidoleic" 2,0 2,0 2,0 2,0 2 , 0 R6sine novolac "1 1 1

B203 3 I 1 1

  Compressibility 5.4 4.8 5.1 5.1 4.5 Breaking stress (N / mm2) Drying time (2800C) 15 min 0.41 0.56 0.56 0.05 0.10

"0.66 0.87 0.87 0.81 1.27

"3.06 3.67 4.43 3.72 3.67

Co CO o

Claims (2)

  1 Refractory masses containing magnesium oxide in particular gassy masses, containing calcined magnesite and / or calcined dolomite as the main refractory material, as well as possibly other usual constituents, and 2 to 8% by weight , calculated with respect to the total composition of a temporary binder system containing a drying oil characterized in that the binder system consists of from 50% by weight of a drying oil to 50% by weight of a fatty acid unsaturated at 20% by weight of a boron compound   5 to 20% by weight of a thermosetting resin.   the total sum of the individual components of the binder system being 100% by weight 2 Refractory masses according to claim 1, characterized in that as a further constituent. they contain 8% by weight, calculated on the total composition. flake graphite, black smoke and / or coke