SU1483223A1 - Method of manufacturing heat plant lining of dry packed mass - Google Patents

Abstract

The invention relates to metallurgy, and in particular, to methods for producing monolithic linings of thermal units, such as induction furnaces. The purpose of the invention is to increase the time between turnarounds by increasing the reliability of the lining. The proposed method of manufacturing the lining provides for initial heating of the lining with a template up to 200-700 ° C, and after removing the template, impregnates the working surface with a binder with a subsequent application of a protective coating based on the refractory component and the binder. The turnaround time is increased by 6 times.

Description

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(21) 4237533 / 23-02

(22) 05/04/87

(46) 30,05.89. Bul Number 20

(71) Eastern Research and Design Institute of the Refractory Industry

(72) V.N.Tonkov, S.Yu.Musikhin, V.P. Sorochkin, Yu.S.Nikitin

and Yu.A.Tashirov

(53) 621.365.52 (088.8)

(56) USSR Author's Certificate No. 665194, cl. F 27 D 1/16, 1974. USSR Copyright Certificate No. 52675.6, cl. F 27 B 14/10, 1974. (54) METHOD OF MANUFACTURING FUTERING OF THERMAL UNITS FROM DRY BATTERIES

(57) The invention relates to metallurgy, in particular, to methods for producing monolithic linings of thermal units, such as induction furnaces. The purpose of the invention is to increase the time between turnarounds by increasing the reliability of the lining. The proposed method for the manufacture of a lining provides for the initial heating of the lining with a template up to 200-700 ° C, and after removing the template, impregnates the working surface with the subsequent application of a protective coating based on the refractory component and the binder. The overhaul period increases 6-s by 6 times.

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The invention relates to metallurgy, in particular, to methods for producing monolithic linings of thermal units, for example, induction furnaces.

The purpose of the invention is to increase the time between turnarounds by increasing the reliability of the lining.

Initial heating of the lining to 200-700 ° C and impregnation of the working surface of the lining with a binder followed by the application of a protective coating based on the refractory component and binder reduces the metallization of the lining, which improves the reliability of the lining and increases the duration of the overhaul period.

An increase in the initial heating temperature to 200–700 ° C makes it possible to detect all possible cracks occurring in the lining as a result of shrinkage and other processes, which, upon cooling, reach the maximum possible value for a given material. The binder applied to the surface of the lining penetrates to the maximum depth of the crack, increasing the adhesion of its entire surface. Due to this, the protective coating contacts with the entire surface of the crack, completely filling the last one and, during solidification and sintering, reinforces and further strengthens the lining during further heating.

The choice of the temperature range of the initial heating of the lining is due to4. oo with

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The flames are as follows. Heating to a temperature of less than 200 ° C does not provide sufficient hardening of the lining, as a result of which in subsequent operations: removing the gauge and loading the metal into the crucible, the lining is destroyed. Heating above 700 ° C is impractical because it does not lead to a significant increase in the reliability of the lining, and the energy costs increase. In addition, at temperatures above 700 ° C, uneven deformation of the template occurs, which causes the lining to collapse when the board is removed for 15 months. (duration

the overhaul period), the B process of operation did not require repairs associated with the jointing of the metallized,

Example 1 On the outer surface of the template of the induction-gel furnace for the melting of aluminum IL-T-6, a compensation is placed with a l oil of 3–5 mm thick roofing material. After the template is installed, the crucible walls are filled with a refractory mass, comprising, by mass, 50% of chamotte, 30% of finely ground magnesite, 5% of quartzite and 15% of sintering additive, containing 34% of borax and 66% of silicate granulate,

Lining packing is performed by pneumatic tamping. Using an electric heater and an inductor, the template and lining are initially heated until the temperature reaches 450 ° C on the bottom and 700 ° C in the upper part of the crucibles. The rate of temperature rise during the initial heating period is 50 K / h, holding at the indicated temperatures for 6 hours. After holding, the liner together with the template is cooled to 50 ° C and the template is removed from the crucibles. In the process of heating, the compensation layer burns out and the template is easily separated from the lining without disturbing its integrity.

The working surface of the lining is impregnated with a binder - liquid glass, then a protective coating of 2 mm thick is applied based on refractory components - chamotte and magnesite, and the binder - liquid glass. The protective coating contains, by mass fraction of 55.0% chamotte, 28.8% of magnesite, 1.2% sodium silicofluoride and 15.0% of liquid glass. The coating is dried for 2 hours, after which the crucible is loaded with metal and a so-called sintering smelting is carried out, during which

cracks, metal extraction and O gasketing by refractory materials. The lining manufactured by the proposed method ensured reliable and safe operation of the furnace in a period significantly exceeding the established standards (1-3 months) for lining from heat-resistant concrete of a similar composition,

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PRI mme R 2. After installing the template with a 2.0 mm thickness fixed on its outer surface of a 2.0 mm paper layer, a wall is filled with a refractory mass of 1 crucible containing a mass fraction of 50% chamotte, 6% quartzite, 30% magnesite and 14% sintering additives, comprising 43% boric acid and 57% silicate lumps. The lining is initially heated by an inductor for 3 hours to reach 45 ° C at the bottom and 200 ° C in the upper part of the crucibles, followed by holding for 3 hours. After cooling to 50 ° C, the template is removed and the working surface of the lining is soaked in phosphate binder. . A protective coating containing a mass fraction of 40% cryolite, 20% boric acid, 10% sylvinite and 30% phosphate binder is applied to the prepared lining surface with a layer of 3 mm and dried for 2 hours. Then the crucible is loaded with metal and for 12 hours Heats up to the occurrence of the melt, after which the crucible is reloaded with liquid metal and the melt is heated to 800-850 ° C with a shutter speed of at least 4-6 hours until insulation is at least 500 ohms.

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lining sintering occurs. The metal is heated and melted within 12 hours. Next, a full crucible is welded and the metal is heated to 850 ° C with a shutter speed of at least 4 hours. With insulation of 500 cm, the furnace is commissioned,

During operation, the insulation is

within 2-4 months, it is 2000–3000 ohms and further increases to 20,000–3,000,000 ohms, thus confirming the minimum metal permeability of the crucibles. The furnace was operated

cracks, metal extraction and packing of fire gates with refractory material. The lining manufactured by the proposed method ensured reliable and safe operation of the kiln during a period significantly exceeding the established standards (1-3 months) for lining from heat-resistant concrete of a similar composition,

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PRI mme R 2. After installing the template with a 2.0 mm thickness fixed on its outer surface of a 2.0 mm paper layer, a wall is filled with a refractory mass of 1 crucible containing a mass fraction of 50% chamotte, 6% quartzite, 30% magnesite and 14% sintering additives, comprising 43% boric acid and 57% silicate lumps. The lining is initially heated by an inductor for 3 hours to reach 45 ° C at the bottom and 200 ° C in the upper part of the crucibles, followed by holding for 3 hours. After cooling to 50 ° C, the template is removed and the working surface of the lining is soaked in phosphate binder. . A protective coating containing a mass fraction of 40% cryolite, 20% boric acid, 10% sylvinite and 30% phosphate binder is applied to the prepared lining surface with a layer of 3 mm and dried for 2 hours. Then the crucible is loaded with metal and for 12 hours Heats up to the occurrence of the melt, after which the crucible is reloaded with liquid metal and the melt is heated to 800-850 ° C with a shutter speed of at least 4-6 hours until insulation is at least 500 ohms.

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During operation, the insulation increases during 1-3 months of operation up to 2,000–3,000 ohms and further up to 10,000–3,000,000 ohms, showing the absence of a through-passage of metal through cracks, which serves as evidence of reliable lining operation. The duration of the overhaul period in this example was 12 months.

As can be seen from the examples of the proposed and known methods, the advantages of the proposal are higher reliability of the lining and longer duration of operation of the heating unit, as well as in the manufacture of lining from the same refractory mass with the same composition as the coating, the duration of the lining between-repairs 6 times higher than in the manufacture of the prototype method.

The proposed method is less energy consuming as compared with the currently widely used method of making lining from heat resistant 83223Q

kih concretes. Implementation of the proposal does not require additional capital expenditures.

Claims (1)

Invention Formula A method of making linings of thermal units from dry printed 10 masses, including packing of the lining with a template that has a compensation layer on the working surface, initial heating of the lining with subsequent removal of the template, application of a protective coating based on the refractory component and a binder, loading of the metal charge or melt and final heating of the lining prior to its sintering, about 20 and 20 so that, in order to increase the duration of the overhaul period by increasing the reliability of the lining, the initial heating of the lining is carried out 25 200-700 C, and before applying a protective coating, the working surface of the lining is impregnated with a binder.