DE3814360A1 - Process for producing synthetic resin-bonded, carbon-containing refractory products - Google Patents

Abstract

The invention relates to a production process for refractory products which are used in converters, pans, electromelting furnaces and in high-temperature facilities. It is an object of the invention to, by means of a suitable energy-saving and cost-minimising production process, prevent inhalation of toxic sulphur and tar gases and ensure a high flexibility in respect of the product quality. According to the invention the object is achieved by a production process in which from 80 to 100% of a liquid synthetic resin are added to the premixed middle and coarse fraction of a refractory component and are mixed in such a way that a homogeneous composition is formed. To the mixture are added, particularly in succession, a carbon support, a fine refractory component and a pulverulent synthetic resin, with the mixture being homogenised after each addition.

Description

Field of application of the invention

The invention relates to a method for producing resin-bonded, carbonaceous, refractory products containing their use in converters, pans, electric furnaces as well in high-temperature aggregates.

Characteristic of the known technical solutions

From the literature are different methods of preparation refractory bricks or other shaped body known. These have been sufficient to refractory products to get certain property values.

With the introduction of carbon-bonded products Existing technologies were no longer sufficient to ensure quality produce high quality products. To the required Achieving property values became a hot mix process with coarse grain preheating in a separate unit and then Hot deformation passed.

A disadvantage of a method is the high energy consumption. In addition, occur in this process pressing technical problems at carbon contents greater than 5%. The higher the carbon content, the lower the compressibility of the mass. Other disadvantages, such as the formation of toxic tar and Sulfur vapors during mixing and pressing and softening the molding in the heating process led to the transition to the Resin bond.

Thus, in DE-OS 31 46 866 a heat-resistant material described with a phenol-formaldehyde resin binder, which are produced by a conventional method can, as it does for pitch-bonded refractory materials is used.

The disadvantage here is the addition of water to achieve a suitable consistency.

In US-PS 42 48 638 is a method for producing a Magnesia carbon stone, wherein a novolak phenolic resin consuming dissolved in a solvent and then a hardener is added.

A similar process includes DE-OS 28 06 506, where also Novolakphenolharz is used as a binder solution. A disadvantage is shown when produced by these methods Products a very low strength of the molding after the molding, which complicates the further processing.

Improvements of these disadvantages are shown in SP 01 58 895, the already possibilities of using a mixture of novolak type and resol type phenol resins.

The manufacturing process will not be discussed in detail, but saying that this is for the optimal property values of products is of great importance.

The disadvantage of this solution is again the use of Water for producing a compressible mass.  

Object of the invention

The aim of the invention is to provide a process for producing carbonaceous, to create refractory products, the one Excludes inhalation of toxic sulfur and tar gases, minimized energy and production costs and a broad Product range with improved product quality.

Explanation of the essence of the invention

The object of the invention is, by a suitable energy-saving and effort-minimizing manufacturing process, a Exclude inhalation of toxic sulfur and tar gases and high flexibility in terms of product quality to ensure.

According to the invention, the object is achieved by a production method solved, at the 80th , , 100% of a liquid synthetic resin on the premixed medium and coarse grain fraction of a refractory Component dosed and mixed so that a homogeneous mass arises. This conglomerate of large refractory Component and synthetic resin become particulate in series Carbon carrier, a refractory fine component and a powdered Synthetic resin added, with one after each addition Homogenization takes place.

This mixture of refractory raw materials and aggregates is then the remaining liquid synthetic resin added and homogenized again.

The entire dosing and mixing process takes place at temperatures of a maximum of 30 ° C, which means working without harmful to health Allows gases.

The mixture becomes larger at a specific pressing pressure equal to 100 MPa molded into shaped articles. The molded bodies a maximum of 20 hours subjected to a curing process. According to the specifics of the molded products Curing starting at 80 ° C to a maximum of 200 ° C, either a one- or two-stage curing of the moldings possible is.

The single-stage hardening takes place at temperatures of 160. , , 200 ° C, the two-stage hardening in the 1st stage at 80. , , 100 ° C and in 2nd level at 160. , , 200 ° C instead.

The chemical reactions taking place in this temperature range of the resin cause a complete cure of the product and give it corresponding properties. The liquid synthetic resin used is is a rosin-type phenol-formaldehyde resin whose B-time a maximum of 2.5 minutes, preferably 1 to 2 minutes. Under the B-time is the time to understand that a phenolic resin needed to get out of the liquid state at a temperature from 150 ° C irrversibly to a gelatinous state. For the powdered synthetic resin used is a novolak type phenol-formaldehyde resin, whose flow path is 20 to 70 mm, preferably 30 to 50 mm. Under the flow path is the route to understand a sample of a solid pressed into tablets Phenol resin on a 60 ° inclined plate at 125 ° C to for curing travels.  The carbon content of the carbon support must be at least 80%.

Compared to conventional technologies for the production of carbonaceous, refractory products that have a processing temperature of about 150 ° C during the mixing and shaping process require, the inventive method minimizes the production costs.

By the application of the mixing technology according to the invention and The use of a low-viscosity synthetic resin is an extremely Homogeneous molding compound achieved, which on the one hand on the processability as well as the quality of the final product positive effect.

embodiment

The invention is based on three embodiments be explained in more detail.

1st example

This example relates to a process for producing resin-bonded, carbonaceous, refractory molding with a residual carbon content of 15%.

The metering and mixing process was carried out at room temperature and is tabulated for clarity.

adding mixing time 1. Medium and Coarse Fraction of Synthetic Magnesite | 30 s 2. 80% liquid synthetic resin 60 s 3. solid carbon carrier 120 s 4. Fine fraction of a synthetic magnesite 180 s 5. powdered synthetic resin 90 s 6. Remainder of the liquid synthetic resin 180 s

The middle and coarse fractions of synthetic magnesite lay in the area

0.1. , , 1.0 mm,
1.0. , , 3.15 mm,
3.15. , , 5.0 mm.

The fine component of the synthetic magnesite is in the range less than 0.1 mm.

The liquid synthetic resin was a phenolic Resolt type formaldehyde resin whose B time is 2 min. at 150 ° C scam.

The powdered synthetic resin was phenol-formaldehyde resin of the novolak type used, which has a flow distance of 50 mm possessed.  

The solid carbon support contained 90% carbon. The molding compound produced was subjected to a specific molding pressure Of 140 MPa molded into refractory moldings. The refractory moldings were subsequently a two-stage Curing regimen in the 1st stage of 4 hours at 90 ° C and in the 2nd stage of 4 hours at 180 ° C subjected. Including heating and cooling, the whole amounted Curing process to 16 hours.

The refractory shaped bodies produced have the following characteristic Properties on:

, MgO content at least 96.5% (determined on annealed substance) @ , density at least 2.85 g / cm ³ , open porosity kl. 5% , Cold crushing strength at least 30 MPa , Residual carbon content at least 15%

2nd example

The example relates to a process for producing resin-bonded, carbonaceous, refractory molding with a Residual carbon content of 6% based on a mixture of different Sintered magnesite. The metering and mixing process took place at room temperature and is tabulated for clarity.

adding mixing time 1. Middle and coarse fraction of a sintered magnesite A | 20 s 2. 100% liquid synthetic resin 120 s 3. solid carbon carrier 120 s 4. Fine fraction of a sintered magnesite B 180 s 5. powdered synthetic resin 180 s

The middle and coarse fraction of sintered magnesite A was in the Range 0.1. , , 1.0 mm and 1.0. , , 3.15 mm. The fine fraction of sintered magnesite B was smaller in size 0.1 mm.

As a liquid resin came a phenol-formaldehyde resin of Resolt type used whose B-time 2 min. at 150 ° C was. As the powdered synthetic resin came a phenol-formaldehyde resin of the novolak type used, which has a flow distance of 50 mm possessed.

The solid carbon support contained 95% carbon. The molding compound produced was subjected to a specific molding pressure Of 140 MPa molded into refractory moldings.  

The refractory moldings were subsequently a two-stage Curing regime in the 1st stage of 4 hours at 80 ° C and in the 2nd stage of 4 hours at 170 ° C subjected. Including heating and cooling, the whole amounted Curing process to 16 hours. The refractory shaped bodies produced have the following characteristic Properties on:

, MgO content at least 90% , (determined on annealed substance) @ , density at least 2.90 g / cm ³ , open porosity kl. 6% , Cold crushing strength at least 80 MPa , Residual carbon content at least 6%

3rd example

The example relates to a process for producing resin-bonded, carbonaceous, refractory molding with a Residual carbon content of 10% based on synthetic Magnesite and fused magnesite.

The metering and mixing process was carried out at room temperature and is tabulated for clarity.

adding mixing time 1. Middle and coarse fraction of a fused magnesite | 20 s 2. 100% liquid synthetic resin 120 s 3. solid carbon carrier 120 s 4. Fine fraction of a synthetic magnesite 160 s 5. powdered synthetic resin 150 s

The middle and coarse fraction of fused magnesite was in the range

0.1. , , 1.0 mm
1.0. , , 3.15 mm
and 3:15. , , 5.0 mm.

The fine fraction of the synthetic magnesite was in the range less than 0.1 mm.

The solid carbon support contained 90% carbon.

As the liquid resin was a phenol-formaldehyde resin of the resol type used, whose B-time 2 min. at 150 ° C was. As the powdered synthetic resin came a phenol-formaldehyde resin of Novolaktyps used, which had a flow distance of 50 mm. The molding compound produced was subjected to a specific molding pressure Of 160 MPa molded into refractory moldings. The Refractory moldings were subsequently a one-stage Curing regime 6 hours at 180 ° C subjected.  

Including heating and cooling, the curing process was on 14 hours.

The refractory shaped bodies produced have the following characteristic Properties on:

, MgO content at least 96% (determined on annealed substance) @ , density at least 2.95 g / cm ³ , Open porosity kl. 4% , Cold crushing strength at least 50 MPa , Residual carbon content at least 10%

The comparison of the embodiments shows that according to the method Resin bonded, carbonaceous, refractory moldings different raw material base and combinations with variable residual carbon contents can be produced.

Furthermore, this process enjoys up to the curing of the Preference that it is possible at room temperature and so on Working without hazardous gases and vapors possible becomes.

Claims (6)

1. A process for the production of resin-bonded, carbonaceous, refractory products based on refractory raw materials, such as sintered magnesites, synthetic magnesites, fused magnesites, dolomites, MgO-Al ₂ O ₃ spinel, recycled material and combinations of these raw materials characterized in that 80. , , 100% of a liquid synthetic resin are metered onto the premixed medium and coarse grain fraction of a refractory component and mixed homogeneously, this comonomer particulate in series a carbon support, a refractory fine component and a powdered synthetic resin is added, the mixture is homogenized after each addition and by addition of the remaining liquid synthetic resin (20% by weight) and subsequent homogeneous mixing, a compressible mass is formed. 2. The method according to item 1, characterized in that the mixing process is carried out at temperatures of maximum 30 ° C; the mass produced in the pressing process at a specific Pressing pressure of greater than or equal to 100 MPa pressed into moldings and the subsequent hardening process is a maximum of 20 Hours. 3. The method according to Pkt. 1 and 2, characterized in that the Shaped bodies are cured in a maximum of two stages, the 1st stage in the temperature range of 80 to 100 ° C and the 2nd stage in the temperature range of 160 to 200 ° C. 4. The method according to Pkt. 1 and 2, characterized in that the Shaped body in one stage at temperatures of 160 to 200 ° C. be hardened. 5. The method according to item 1, characterized in that as a liquid Resin phenol-formaldehyde Resoltyp resin for Use comes whose B-time at 150 ° C for a maximum of 2.5 min, preferably 1 to 2 minutes and as a powder Synthetic resin, a novolak type phenol-formaldehyde resin for Use comes, the flow path 20 to 70 mm, preferably 30 to 50 mm. 6. The method according to item 1, characterized in that the solid Carbon carrier contains at least 80% carbon.