DE3438082A1 - MOLDED FIRE-RESISTANT ELEMENT, EXAMPLE FIRE-RESISTANT BRICK OR BLOCK - Google Patents

Description

.-- .: Phvs.H.Baitefe

Dr. Ing.M.Held

Patent Attorneys · Lange Straße 51 ■ D-7000 Stuttgart 1 teimlufopisS ^ tentamt

October 15, 198 4 Reg. 126 80 7 487333 osd

DOLOMITE DI MONTIGNOSO SOCIETA PER AZIONI 1-16121 Genova / Italia

Cast refractory element, such as a refractory brick or block

The invention relates to a refractory element according to the preamble of claim 1.

The basic material of the element is a mixture, preferably based on magnesite, dolomite and / or other refractory insulating materials. Suitable binders can also be used may be added, for example tars, resins, pitch or other additives, either alone or in combination are included with each other. The mixture thus formed is then treated by means of presses and / or vibrators to to bring them into the desired shape. It is known that refractory bricks have an initial high temperature baking process must go through to increase their compactness and strength, or a drying process at about 300 ° C, to drive off at least the volatile tar constituents.

As can be seen, these baking or drying processes lead to increased production costs.

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The invention is based on the object of providing a refractory element that is comparatively cheaper to manufacture to accomplish.

According to the invention, this object is achieved by the features of Claim 1 solved. The invention accordingly provides that the brick mixture during the preparation phase Enrichment with a metallic substance that is distributed over the mass is given, in particular an enrichment with metal needles.

The refractory brick enriched in this way is given a strength that allows it to be used immediately and to omit the processes mentioned above, even in the cases where these processes were previously indispensable.

In addition to the above-mentioned metal needles, there are randomly distributed metal threads, metal balls, chips and the like can be used with advantage.

The special features of the invention are summarized and shown in the claims. The items and benefits A wide variety of types emerge from the following description with particular reference to the examples listed below.

example 1

For the production of tarred raw bricks from dolomite for use in smelting technology, the following is used Components assumed:

Dolomite (grain size: O to 2 mm) 50%

Dolomite (grain size: ₂ to 4 mm) 25%

Dolomite (grain size: 4 _b is 8 mm) 15%

Dolomite (grain size: _{8 to} 12 mm) 10%

.ψ.

Stainless steel needles

(0.4 mm diameter and 25 mm length) 3%

Tar 5%

The mixture obtained in this way is pressed into the shape of the desired brick in casting molds. After the molding process can the brick can be used immediately for the installation. As a rule, bricks of this type that do not have the addition of Own steel needles, a baking process with a high tempera door if they are intended for use in harsh operating conditions. You can also do one Drying process at 300 ° C to remove the volatile components of the tar, so that during the first time the furnace is heated, the risk of collapse due to the softening of the furnace is avoided Tar is coming. The addition of metallic particles prevents the brick from collapsing, making it safe to use the same is made possible in the raw state.

Example 2

For the production of dried and tarred blocks from DoIomite the following components are assumed:

Dolomite (grain size: 0 to 2 mm) 40%

Dolomite (grain size: 2 to 4 mm) 30%

Dolomite (grain size: 4 to 8 mm) 20%

Dolomite (grain size: 8 to 14 mm) 10%

Tar 5%

Ordinary steel needles

(Diameter 0.5 mm, length 35 mm) 1.5%

The mixture thus obtained is shaken in suitable molds and subjected to drying at 300 ° C, after which the block is ready for use.

The blocks are made of dolomite, magnesite and similar material basically in the raw state. because the risk of collapse is avoided during the heating phase due to their large dimensions and due to the installation resulting mutual support. If metallic particles are added, however, a drying process can be used if necessary be carried out for ecological reasons.

However, if such large blocks are used without the presence of the metallic components provided according to the invention are placed in a drying oven, then they collapse due to the lack of mutual support, how it arises within the toric structure of the masonry in which they are installed for operation is divided this masonry expands during the heating process, so that the blocks against each other and against the surrounding furnace wall are pressed, the blocks will collapse inwards due to the arching effect of said structure prevented.

Example 3

For the production of magnesite bricks that are tarred and optionally have dried, the following components are assumed:

Magnesite (grain size: 0 to 2 mm) 50%

Magnesite (grain size: 2 to 4 mm) ...... 30%

Magnesite (grain size: 4 to 8 mm) ...... 20%

Tar 5%

Stainless steel needles

(Diameter 0.40 mm, length 25 mm) ² %

The bricks are obtained by pouring the mixture into casting molds in which they are put under pressure.

A possible drying process can be carried out by increasing the temperature of the bricks to 300 ° C.

In this case the drying process can be faster and more regular be carried out because the temperatures of the inner and outer brick walls differ due to the conductivity Quickly compensate for the added iron, creating tension as well as possible cracks and deformations be prevented. The drying process is accelerated in this way, which leads to a corresponding reduction in costs and increase productivity.

It appears that the bricks or blocks according to the invention have greater mechanical strength and dimensional stability in both cold and hot conditions. Their "greater strength means that they are critical Better to endure handling operations and the stresses to which they are subjected during the preheating and heating of the oven are. It was also found that the internal stresses caused by temperature differences are lower are, a circumstance that increases the life of the built-in brick. The omission of the baking process or the drying process has no detrimental effect on the service life and operating behavior of the installed bricks. The omission these processes even lead to a reduction in rejects because none were damaged during intermediate handling Pieces need to be eliminated. Although the present invention with particular reference to the above Examples has been described, it goes without saying that many modifications and developments are possible without the To leave the scope of the invention as outlined in the following claims.

Claims (3)

Claims 1. Cast refractory element, such as refractory Brick or block, made from a mixture based on dolomite, magnesite or the like, standing on its own or in combination with one another, optionally with the addition of a binder, such as tar, pitch or the like, characterized in that a metallic substance is added to the mixture, e.g. in the form of chips, Beads, needles and / or threads or the like, each of these shapes being present on its own or at least two of these forms are provided at the same time. 2. Element according to claim 1, characterized in that the metallic substance is preferably present in an amount of 0.5 to 5.0 percent by weight. 3. Element according to claim 1 or 2, characterized in that the metallic substance is arranged in the form of distributed Needles is present, the diameter of which is 0.1 to 1.0 mm and the length of 10 to 100 mm, preferably 15 to 20 mm.