ES2542479B1 - Procedure for treating the refractory lining in single-layer ceramic roller furnaces, and powder base product used. - Google Patents

Abstract

Process for treating refractory lining in single-layer ceramic roller furnaces, and product used. # The invention relates to the way of applying a refractory lining in single-layer ceramic roller furnaces comprising connecting the oven suction, removing the rods Pyrometers of the oven, covering the oven roll-passers by means of rigid cardboard, mixing the powdered base product with water, stirring the mixture for 15 minutes, resting the mixture for 48 hours, stirring the mixture before application until homogeneity is achieved. , apply to the first layer of the homogeneous mixture in the oven vault by means of a gun and / or on the wall of the oven using a gun or trowel, let dry at least two hours from the first application, add powder material to the prepared mixture, stir again , and finally apply a second layer using a trowel or trowel. The powdered base product contains more than 55% Zirconium, a silica and magnesium whose sum in content is greater than 35%.

Description

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PROCEDURE FOR TREATMENT OF REFRACTORY COATING IN MONOSTRATE OVENS OF CERAMIC ROLLERS. AND PRODUCT BASED ON

EMPLOYEE POWDER

D E S C R I P C I O N

OBJECT OF THE INVENTION

The present invention relates to a refractory lining treatment in single-layer ceramic roller furnaces from a specific process and the product that is applied to the interior of the oven as a ceramic coating.

Asl, the product that is applied contains zirconium as the main product.

The object of the invention is to repair the mono-layer furnaces and / or protect them against chemical attack, avoiding condensation and temperature differences inside the oven, thus allowing the prolongation of the good condition of the interior walls of the oven and minimizing the production of parts stained or defective.

The treatment described in the present invention is applied both in furnaces whose refractory is new and in those that the refractory is already damaged and its sanitation is desired.

BACKGROUND OF THE INVENTION

Single-layer roller ovens are used for the manufacture of ceramic products, specifically tiles and tiles, and that due to the characteristics of the manufacturing process, these ovens withstand different temperatures during cooking.

Thus, the ovens are integrated by different modules where each one can reach a certain temperature depending on the needs required in that area.

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During preheating, just before the cooking of ceramic products, gases and vapors are generated mainly with a high content of lead and / or sulfur, which cause the chemical attack of the interior walls of the furnaces and the deterioration of their coating refractory in a short space of time.

In order to treat the refractory linings of the mono-layer furnaces, either of a new furnace or of an oven damaged by use, a mass of cement is applied on the walls, vault and / or floor in those most deteriorated areas.

Among the practices that are followed today, the application of this cement mass is known as patches inside the oven. However, this application causes its cracking in the medium term, this being a not recommended solution that does not prevent the chemical attack of the condensed gases during cooking.

Thus, we observe that in the state of the art there is no known procedure or applied product that is used in the treatment of single-layer roller furnaces that allows extending the useful life of the oven, withstanding high temperatures without its crystallization or cracking taking place and Avoid oven contamination.

DESCRIPTION OF THE INVENTION

The procedure that has been recommended has been designed to clean the lining of ceramic roller monolayer furnaces, protect them from chemical attack caused by gas condensation and withstand high temperatures.

Thus, in the process of treating the refractory lining in monolayer ceramic roller furnaces a coating is used which is prepared from a base powder product with a content greater than 55% in Zirconium.

The phases that must be followed for the furnace treatment are described below:

a) Connect the oven aspiration in order to avoid dust generated during aspiration,

b) Remove the pyrometric gray hair from the oven,

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c) Cover the oven roll-passers by means of rigid cardboard strips or any similar material of high rigidity,

d) Mixing the powdered base product with water,

e) Stirring the mixture for 15 minutes in order to reach a homogeneous mixture, where this mixture is prepared 48 hours before application,

f) Rest the mixture for 48 hours until its application,

g) Before application, stirring the prepared mixture until it reaches homogeneity,

h) First application of the homogeneous mixture on the walls, vaults and / or floor of the oven to be treated by means of a gun or trowel,

i) After at least two hours from the first application, add to the prepared mixture material of the base powder and stir again,

j) Apply a second coat using a trowel or trowel at least two hours after the first application.

As detailed, the applied coating is composed of at least two layers where the sum of both requires a quantity of homogeneous mixture that is between 3.5 kg / m and 7 kg / m.

Thus, if the mixture used has a value below 3.5 kg / m2, the amount of the mixture would not be sufficient to withstand high temperatures. However, if the amount of mixture applied to the interior of the oven were greater than 7 kg / m, it would be very heavy and not be properly adhered to the wall.

When the oven refractory is damaged or soft, it is advisable to carry out a stage prior to stage a) of cleaning the area. Specifically, it is necessary to remove the damaged or soft area until a hard refractory is reached.

On other occasions, the oven has enamel stains inside it, so before proceeding with the detailed procedure, a stage prior to stage a) of sanitation of the area is necessary, using a radial or brush with the purpose of of removing this spots.

Necessarily the prepared homogeneous mixture is applied on the inside of the oven

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by guns with an air pressure between 3 and 8 kg, the inner nozzle passage between 6 mm and 15 mm and the outer nozzle passage between 3 mm and 10 mm.

The gun application is made 40 cm away from the wall or vault.

As detailed in step d) it is necessary to mix the powdered base product with water in proportions such that a homogeneous mixture is obtained for the first application which has at least 0.8 gr / cm density.

On the other hand, for the application of the second layer of the homogeneous mixture in step i) the need to add more quantity of powdered base product is detailed in order to increase the density of the mixture prepared for its application of the second cap. Specifically, the second layer that is applied in step j) has a density of at least 1.5 gr / cm.

In order to ensure that the first application of the mixture is dry, we wait at least two hours from the first application when new ovens are treated. However, when the oven's refractory lining is badly damaged, it is advisable to wait at least 72 hours from the first application for drying at room temperature before proceeding to the second application.

As for the powder base product used in the oven treatment procedure described, it has a content greater than 55% in zirconium, the sum of the content of silica and magnesium exceeding 35%.

To start the oven, once the coating application has been carried out, it is necessary to gradually heat the oven.

Thus, when the treatment has used less than 500kg of product, the oven is started as follows:

- First, the burners on the bottom of the stove are lit, specifically between 16 and 24 according to the oven,

- After 8 hours, the temperature is increased to 800 ° which is maintained for 4 hours, and

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- From that moment on, a work curve is programmed in order to increase 6 ° at the time.

In case the quantity of product applied has exceeded 500kg, the oven start-up is carried out as detailed below:

- After at least 8 hours after application, the oven is heated at 300 ° C for 6 hours,

- It increases at a temperature of 400 ° C in two hours and is maintained for 6 hours, and

- From that moment, the temperature is increased by 50 ° C in two hours and maintained for 10 hours. The gradual curve described here is from 450 ° C to 1100 ° C

- After the temperature rises directly to the working temperature of the oven, that is, up to 1150 ° C when coating is produced, 1180 ° C when glazed porcelain is manufactured and 1200 ° C when it comes to technical porcelain.

The advantages of the application of the described product and the follow-up of the procedure are detailed below:

- Protection of the oven refractory, delaying the maintenance repairs in the oven up to 10 years from the application of the treatment, thus avoiding high annual maintenance costs.

- The applied coating withstands temperatures up to 2000 ° C, in fact this coating absorbs the oven temperature and keeps the areas warm homogeneously in addition to radiating the temperature.

- The applied coating prevents condensation at the oven inlet.

- The applied coating does not crack.

- The applied coating does not crystallize.

- The applied coating prevents contamination inside the oven.

- The applied coating is not toxic.

- The applied coating makes it possible to increase the quality of the manufactured tiles.

- The coating applied enables energy saving, since after application the furnaces are completely sealed, avoiding any energy leakage.

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- The applied coating protects the refractory present inside the oven, preventing them from being harmful to health.

In ceramic furnaces, the presence of a high content of lead and sulfur produces a condensation of alkaline vapors from the entrance to the first burner.

This occurs because the vault of this area is cold, so condensation is generated that causes problems in the production of tiles, since after a few weeks there are beginning to be broths of green drops that cause innumerable losses because they contaminate the tiles. These tiles have to be discarded, since they cannot be sold.

To date, the only solution was to stop the product entering the oven and increase the temperature of the affected areas to more than 1000 ° C to perform a pyrolysis.

This stop implied a loss of more than two hours of production.

By applying the product described in the present invention inside the oven, the problem described above is immediately eliminated, since the vault of the hot oven is maintained and the adhesion of the pollutants on its walls is prevented.

Thus, the additional advantages offered by the product of the present invention applied following the described steps allows:

- Considerable increase in the percentage of first material due to the non-contamination of the pieces per drop of drops.

- Increased productivity by not having to make holes in the oven to eliminate condensation through temperature rises.

- Savings in maintenance costs, since there is less deterioration of the refractory caused by temperature rises to eliminate condensation.

On the other hand, ceramic ovens increasingly have a wider useful mouth to increase tile production. This also leads to larger temperature differences between the sides of the oven and the center. These differences of

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temperature generate a greater number of tones, in the case of cladding, and different calibers in the case of pavement. Differences in tone and caliber generate an increase in the stock of references for the same product.

Advantageously, the application of the described product keeps the temperature constant by allowing the reduction of tones and calibres and entails producing a more uniform stock, reducing the number of claims by the buyer.

EXAMPLE OF PREFERRED EMBODIMENT

The procedure is applied, as described above, to a single-layer ceramic roller furnace, so that the homogeneous paste or mixture previously prepared from a powdered base product is applied, using the steps and components in the proportions already indicated in the section of the "description of the invention".

Claims (9)

5 10 fifteen twenty 25 30 R E I V I N D I C A C I O N E S 1. - Procedure for treating the refractory lining in single-layer ceramic roller furnaces, characterized in that the coating used is prepared from a powder base product with a content greater than 55% in Zirconium comprising the phases of: a) Connect the oven aspiration, b) Remove the pyrometric gray hair from the oven, c) Covering of the furnace roller passers by rigid cardboard, d) Mixing the powdered base product with water, e) Stirring the mixture for 15 minutes, where this mixture is prepared 48 hours before its application, f) Rest the mixture for 48 hours until its application, g) Stirring of the prepared mixture before application until homogeneity is achieved, h) First application of the homogeneous mixture on the walls, vaults and / or floor of the oven to be treated by means of a gun or trowel, i) After at least two hours from the first application, add to the prepared mixture material of the base powder and stir again, j) Apply a second layer using a trowel or trowel, at least two hours after the first application. 2. - Procedure for treating the refractory lining in single-layer ceramic roller furnaces, according to claim 1, characterized in that the sum of the amount of the first and second application of the homogeneous mixture is between 3.5 kg / m and 7 kg / m2. 3. - Procedure for treating the refractory lining in single-layer ceramic roller furnaces, according to claim 1, characterized in that a phase of cleaning the area is performed before stage a) when the furnace refractory is damaged or soft, proceeding to its Withdrawal until a hard refractory is reached. 4.- Procedure for the treatment of refractory lining in mono-layer furnaces 9 5 10 fifteen twenty 25 ceramic rollers, according to claim 1, characterized in that a phase of cleaning the area with radial or steel barbed brush is carried out before stage a) when the oven refractory has enamel stains. 4. - Procedure for treating the refractory lining in single-layer ceramic roller furnaces, according to claim 1, characterized in that the application of the mixture is carried out with guns with an air pressure between 3 and 8 kg, the internal nozzle passage being between 6 mm and 15 mm and the passage of the outer nozzle between 3 mm and 10 mm. 5. - Procedure for treating the refractory lining in single-layer ceramic roller furnaces, according to claim 1, characterized in that the first application of the homogeneous mass is made by a density mixture of at least 0.8 gr / cm. 6. - Procedure for treating the refractory lining in monolayer ceramic roller furnaces, according to claim 1, characterized in that the second application of the homogeneous mass is made by a density mixture of at least 1.5 gr / cm. 7. - Procedure for treating the refractory lining in single-layer ceramic roller furnaces, according to claim 1, characterized in that when the refractory is very damaged the second application is carried out after at least 72 hours from the first application. 8. - Powdered base product used in the treatment procedure described in the preceding claims, characterized in that it comprises a content greater than 55% in zirconium and a sum of the content of silica and magnesium greater than 35%.