HU209120B - Process for producing chemical-ceramic bonded, refractory stamping mass bgased on mullite zircon silicate - Google Patents

Abstract

Fireproof mullite-zirconiumsilicate based gap filling tamping agent is improved by homogeneous admixt. of fine particle size Al(OH)3 to dry chemical components, that would otherwise weaken the fire resistance of the bonding phase. By this admixt. a satisfactory distribution of chemical agents is obtd. and close contact with the fine particle size and most fire resistant component of the system, aluminium-oxide, is achieved. - Prepn. of monolithic furnace brings resistance to high temps. and corrosive melts is accomplished.

Description

The chemical-ceramic bonded refractory ramming compound of the present invention is capable of exhibiting adequate thermophysical and thermochemical resistance to liquid metal and / or slag as working liners for high temperature metal and silicate melts (pig iron, steel, cast iron, etc.). and its corrosion effect.

Monolithic lining has become widespread in recent decades to confine these workspaces. These liners generally use refractory materials consisting of chemically or chemically ceramic-bonded, highly flammable oxides (e.g., Al ₂ O ₃ , Cr ₂ O ₃ , MgO, MgOxCaO, ZrO, etc.).

These oxides, due to their high fire resistance and high corrosion resistance, can withstand the reduction in fire resistance caused by the use of binder clay and chemical without reducing the resistance of the monolithic masonry below the permissible limit. A major disadvantage of these solutions is that the oxides which form the base of the mass are very expensive and / or have too high heat loss. The former significantly increases the specific costs, while the latter requires the installation of a heat-insulating masonry layer, which complicates and makes the construction costly. At the present state of the art, it is common for steel to be produced using oxygen and casting is carried out in a continuous steel casting. This condition means higher melting temperatures and longer residence times for the masonry. This need is not met by chamomile liners used in conventional steel fabrication technologies, which are good for thermal insulation.

In their search for the optimum solution, many R&D professionals have come to the idea that many practical examples can be found that, as a reasonable combination of the two solutions, zirconium silicate and aluminum silicate systems containing 50-60% Al ₂ O ₃ it is advisable to install it in wall structures exposed to increased stress. (JD Bondar: OGNYEUPORÜ 1987, 9, pp. 37-42, Klein, W.: Stahl und Eisen, 1982, III, 102, pp. 217-221, G, Nagy: Energy Management, XVIII 4 142-145).

The use of the above-mentioned solutions entails significant risks, since these refractory systems, especially in basic oxygen steel production, are at the limits of their tolerance. Thus, small amounts of binder overdose or uneven distribution of it can cause rapid wear and unexpected masonry puncture.

The solution of the present invention results in the reduction of the latter hazard by first mixing the minimum required monoaluminium phosphate binder with the high flame retardant A1 ₂ O ₃ carrier (alumina hydrate) and subsequently admixing it with the dry refractory base mixture.

Thus, the additive with the highest fire resistance and the highest specific surface area is homogeneously distributed (in suspension) as a binder phase to a dry mixture of different particle sizes and chemical compositions, significantly increasing the binder efficiency. Ultimately, this forms a stable refractory system with good and better strength, both raw and transient, as well as better than conventionally prepared refractory masses.

Example 1

Chemical-ceramic-bonded ramming compound for the working wall of steel castings used for taping steel in LD converters and UHP furnaces:

Dry mix:

(1.00 to 3.00 mm) (under 45 µm) (0.001 to 1.50 mm) by weight% MULLIT (3 Al ₂ O ₃ x 2 SiO ₂ ) by weight by weight MULLIT (3 Al ₂ O ₃ x 2 SiO) ₂ ) Ground

40% by weight Zirconium silicate (ZrOxSiO ₂ Ground by weight% Upper Petite refractory clay (0.001-1.00 mm) + 50 liters monoaluminium phosphate (Monalfo-48 brand refractory binder solution, available from Magyaróvári

Manufactured and placed on the market by the alumina and artificial corundum factories) and a homogeneous mixture of 50 kg of alumina hydrate [A1 (OH) ₃ ] per tonne of dry mixture.

The dry mixture can be produced at the factory or at the place of use, and can be stored for several months with proper packaging or moisture-free storage, without loss of quality.

The suspension of alumina hydrate [A1 (OH) ₃ ] and Monalfo-48 can be added to the dry part and mixed with the dry part no more than six hours prior to application, with the exact knowledge of the material requirements of the masonry to be formed.

The work can be done manually or mechanically between the permanent liner or the removable steel template.

Removing the template, heating the masonry and putting it into use is the same method used for other types of chemical-ceramic masses.

The use of the exemplary ramming compound, when properly handled, provides one hundred doses of masonry durability, subject to one or two slag changes.

Claims (1)

A process for the preparation of a mullite zirconsilicate based, chemically ceramic bonded refractory scouring compound based on a dry mix of mullite, zirconium silicate and refractory clay dry base and monoaluminium phosphate refractory binder solution and a mixture of alumina hydrate and a homogeneous mixture of The mile hydrate suspension is prepared separately and added to the dry mixture up to six hours before use.