AT398205B - FIREPROOF MASSES OR KITTS AND THEIR USE - Google Patents

Description

AT 398 205 B

The invention relates to refractory compositions or putties containing conventional refractory materials and fatty acids as temporary binders and optionally other conventional components, and the use of such compositions and putties.

It is already known to use fatty oils or grease as a temporary binder in refractory compositions or putties. However, these only act as a result of their greasy consistency, however, when they are subsequently used in such compositions or putties, i.e. when heated, like other organic, carbon-containing materials, can form a binding carbon structure as a result of their thermal decomposition. DE-AS 1 471 297 discloses unburned or baked materials based on magnesium oxide, MgO, which can be used in the construction of containers, such as furnaces, for melting metals.

These known refractory materials based on MgO contain 0.1 to 15% by weight of at least one aliphatic hydroxytricarboxylic acid or a salt or an ester of such an acid, e.g. Citric acid or its salts. By using such hydroxytricarboxylic acids or their salts or esters, which should preferably be water-soluble, a setting mixture, i.e. get a cement-like mixture. The magnesium oxide material should not be plastic and finely divided, as an example here is dead burned magnesite. Furthermore, from DE-AS 1 257 051 a refractory ramming mixture is known, which is bound by means of non-aqueous, carbon-containing binders in the form of an unsaturated, flowable pitch, which is obtained as a residue in the distillation of vegetable oils to remove the fatty acids, such Residue terms are also referred to as fatty acid pitches, ie such pitches still contain unsaturated fatty acids and have an acid number of 30 to 60. The refractory materials used together with these fatty acid pitches can also be basic aggregates, e.g. Dolomite, dead-burned magnesite, hard-burned calcium oxide or mixtures thereof. Furthermore, DE-AS 1 274 489 discloses a temporary binder for ceramic-bound, basic, refractory materials, the binder consisting of a mixture of a medium and / or hard pitch and a fatty acid pitch, the fatty acid pitch advantageously having an acid number of 20 to Should have 40. According to both DE-AS 1 257 051 and DE-AS 1 274 489, only dead-burned materials are used as basic, conventional refractory materials. According to DE-OS 21 19 668, too, a fatty acid pitch is used as a temporary binder, but here additionally granular phosphorus pentoxide, P2O5, is used. According to this DE-OS, dead magnesite is used in the case of using magnesite as refractory material.

DE-OS 33 04 119 discloses basic refractory compositions which contain 3 to 8% by weight of binder, of which 0.1 to 2% by weight have to be organosilicon compounds, in addition to which i.a. unsaturated oils such as oleic acid may also be present, but nothing is said about a content of reactive MgO in this DE-OS 33 04 119.

Also known from US Pat. No. 3,729,329 are binder systems for refractory ramming compounds, which consist of a mineral oil and magnesium stearate, the oil being described as required for tamping and the magnesium stearate as required for setting.

The object of the present invention is to provide refractory masses or putties which are storable, i.e. processable for a long time and in particular remain plastic, which, however, after their application, e.g. as ramming compounds, molding compounds or as putty for grouting to keep the shape they were given and when used, i.e. When heating, crack-free linings without joints result, which have a high resistance to slag attack and crack formation.

It has now been found that long-chain, liquid fatty acids, in conjunction with reactive MgO, form such a temporary binder, so that the excellent properties of the compositions or putties obtained therewith in their processing and use, i.e. after heating or burning in use.

Fireproof masses or putties of the type mentioned in the preamble of claim 1 are therefore used to solve this problem, which are characterized in that they are composed of 1-8% by weight of liquid long-chain fatty acids with more than 8 carbon atoms and 0.2 to 0 , 4 wt .-% reactive MgO, each based on the total mixture, are produced.

Advantageously, the reactive MgO can be caustic-fired and / or finely ground magnesia and / or dolomite sintered flour.

Advantageously, the fatty acid can be an unsaturated fatty acid, e.g. an oleic or linoleic acid.

According to a further preferred embodiment, the refractory compositions or putties additionally contain an extender. Examples of such preferred extenders are mineral oils, fatty oils, stand oil, heating oil, lecithin, bitumen, tar oil (anthracene oil), tar, pitch or waxes, especially soft waxes. As a result, the plasticity of the composition or putty according to the invention can be set as desired 2

AT 398 205 B; furthermore it can be achieved that when using the masses or putties, i.e. when they heat up and decompose the organic constituents they contain, a higher percentage of carbon formed by decomposition of the organic constituents is produced, which can be advantageous for certain applications. 5 Common, possibly contained components can e.g. surface-active substances, substances which cause chemical bonding, such as monoaluminum phosphate, or also fibrous constituents, such as mineral fibers or carbon fibers. Another, optionally, contained component can also be finely divided, i.e. flour-shaped refractory material, e.g. Alumina, bauxite dust or Ο2Ο3 (green).

The amount of fatty acid is 1.0 to 8% by weight and the amount of reactive MgO is 0.2 to 4 10% by weight, based in each case on the total mixture, when an amount of 8% by weight of fatty acid and 4% by weight is exceeded % of the reactive MgO generally does not result in an increase in the advantageous properties with regard to the processing and use of the compositions or putties. Of course, it is possible, however, that the usual refractory material also consists of active, possibly granular, MgO-Kauster, so that the aforementioned, preferred upper limit of 4% by weight of the 75 reactive MgO can also be easily exceeded. Refractory compositions or putties which contain MgO as the usual refractory material are particularly preferred. Advantageously, this MgO refractory material is a dead burned magnesite or dolomite.

The compositions and putties according to the invention are particularly preferably used as ramming compositions for lining furnaces, but also as slinging compositions, casting compositions or vibrating compositions. You can also add 20 to briquettes, e.g. by pressing. Refractory bricks can also be made from it in the same way.

The liquid, long-chain, organic fatty acids used in the refractory compositions or putties according to the invention have carbon numbers above 8, preferably above 12. These can be individual fatty acids or the commercially available fatty acid mixtures. In general 25 the fatty acids have no carbon numbers higher than 30. Unsaturated fatty acids are used which are liquid at normal temperature; Examples include oleic acid, linoleic acid and linolenic acid, i.e. Fatty acids with 18 carbon atoms.

The reactive MgO used in the refractory compositions or putties according to the invention in connection with the fatty acids is usually a relatively finely divided material, i.e. it usually has a grain size below 0.5 mm and advantageously below 0.2 mm. However, it is also the use of flour-like reactive MgO, i.e. possible with a grain size below 0.09 mm and preferably 0.044 mm.

It has now been found that when e.g. pure oleic acid, which is a thin liquid, with reactive MgO, a viscous, sticky product is obtained, which is the temporary binder in the 35 compositions or putties according to the invention. It is therefore believed that there is a chemical reaction between the fatty acid and the reactive MgO. It is not known whether water is released in such a chemical reaction or whether the water itself remains bound. However, no adverse properties were found, e.g. a gradual destruction of ramming bodies bound with a temporary binder according to the invention, e.g. Dolomite-40 rams. The reaction product of the fatty acid and the reactive MgO, which is a viscous, sticky mass, is therefore probably due to the advantageous properties both in the processing and in the use of the refractory masses or putties produced therewith.

The refractory materials contained in the refractory compositions or putties according to the invention are customary refractory materials, preferably basic refractory materials. Examples of these are burnt dolomite, burnt magnesite, burnt lime or mixtures thereof. However, other refractory materials such as chrome ore, aluminum oxide, silicates or silicon dioxide (quartz) can also be used as refractory materials or as an admixture to the basic refractory materials mentioned above.

The term "conventional refractory materials" used here includes the refractory materials of conventional classification, the maximum grain size usually being 12 mm and advantageously 6 mm. The 50 expression " common refractories " however, also includes a certain proportion of finely divided materials such as flour-shaped materials, which proportion can be up to 40% of the refractory materials.

The invention is illustrated by the following examples: 55 Example 1

This example concerns a tamping mass. 65 parts by weight of a dead-burned magnesite with a grain size of 0.2 to 4 mm and 35 parts by weight of flour-shaped, dead-burned sintered magnesite with 3

AT 398 205 B with a grain size of up to 0.09 mm mixed in a mixer together with 0.3 part by weight of a reactive MgO with a maximum grain size of 0.1 mm. For this purpose, a liquid mixture of 1.8 parts by weight of oleic acid, 1.2 parts by weight of mineral oil and 0.8 parts by weight of base oil was added and mixed in a mixer at an ambient temperature of about 22 ° C. for 15 minutes. A crumbly pounded mass was obtained which had a storage time of more than 4 weeks and could easily be used for stamping out a stove. After heating the stamped lining, no cracks were found in it.

Example 2

The procedure of Example 1 was repeated, except that a mixture of 0.8 part by weight of oleic acid and 1.9 part by weight of lecithin was used as the liquid constituent. The ramming mass obtained was particularly suitable for the production of wall parts.

Example 3

A ramming mass consisting of 80 parts by weight of granular dolomite sinter with a grain size of 0.5 to 4 mm, 20 parts by weight of flour-shaped sintered dolomite with a maximum grain size of 0.2 mm and 0.5 part by weight of reactive MgO a maximum grain size of 0.1 mm and a liquid mixture of 3 parts by weight of oleic acid, 0.5 parts by weight of lecithin and 0.8 parts by weight of base oil according to the procedure of Example 1. This mass was an excellent ramming mass for pans.

Example 4 100 parts by weight of reactive MgO with a grain size of 0 to 4 mm were mixed with 9 parts by weight of binding tar and 5 parts by weight of oleic acid in a mixer, giving a crumbly mass which was used to produce briquettes on a Roll press was used. These briquettes were very well suited to chemically and physically regulate the slags that occur in steel production vessels.

Example 5

From 65 parts by weight of a dead-burned magnesite with a grain size of 0.2 to 4 mm and 35 parts by weight of flour-shaped, dead-burned sintered magnesite with a grain size of up to 0.09 mm, 0.5 parts by weight of a reactive MgO a maximum grain size of 0.1 mm, 3.5 parts by weight of oleic acid, 3.5 parts by weight of soft wax, 2.3 parts by weight of tar and 2 parts by weight of pitch, a mixture was prepared, which was initially in Form of a porridge was present. This mixture was pasty in consistency after about 2 days. This mixture can be used in hot ovens as a hot-melt liquid.

Example 6

The procedure of Example 5 was repeated, using the following mixture: 100 parts by weight of the mixture of dead-burned magnesite of different grain sizes, 0.3 part by weight of reactive MgO with a maximum grain size of 0.1 mm, 2 parts by weight. Parts by weight of oleic acid, 3.5 parts by weight of the binder tar used in Example 5, 2 parts by weight of the hard pitch used in Example 5 and 5 parts by weight of bitumen. This mixture was initially in a pulp-like consistency and was solidified into a putty after 2 days. This putty could also be used as a hot-melt casting compound for the repair of hot ovens.

Example 7 100 parts by weight of sintered dolomite with a grain size of 0-7 mm were mixed with 9% bitumen and 5% oleic acid and 1% reactive MgO in a mixer, giving a crumbly mass which was used to produce briquettes on a roller press was suitable. These briquettes were used for repairs to worn parts of a converter, e.g. the scrap site, used successfully. 4th

Claims (7)

AT 398 205 B Example 8 100 parts by weight of a mixture of still-burned magnesite of different grain sizes with 0.4 parts by weight of reactive MgO, 2 parts by weight of carbon black, 1 part by weight of viscous mineral oil and 2 parts by weight of oleic acid was thoroughly mixed in a mixer at 20 ° C. This mixture could be pressed into shaped blocks on a press. The shaped blocks could be used with or without after-treatment, e.g. Annealing can be used for the delivery of metallurgical vessels. 1. Refractory masses or putties, containing customary refractory materials and fatty acids as temporary binders, and optionally other usual ingredients, characterized in that they contain 1 to 8 wt .-% liquid, long-chain fatty acids with more than 8 carbon atoms and 0, 2 to 4 wt .-% reactive MgO, each based on the total mixture are produced. 2. Refractory masses or putties according to claim 1, characterized in that the reactive MgO is caustic MgO and / or finely ground magnesia and / or dolomite sintered flour. 3. Refractory masses or putties according to claim 1 or 2, characterized in that the fatty acid is an oleic or linoleic acid. 4. Refractory masses or putties according to one of the preceding claims, characterized in that they contain an extender. 5. Refractory compositions or putties according to one of the preceding claims, characterized in that they contain mineral oils as extenders. 6. Use of the masses or putties according to the preceding claims as ramming masses, sling masses, molding masses for the production of briquettes, casting masses or vibrating masses. 7. Use of the masses according to the preceding claims for the production of refractory bricks. 5