SU1560564A1 - Method of applying refractory coating - Google Patents

Abstract

The invention relates to metallurgy and can be used in metallurgy and machine-building enterprises when applying coatings on refractory walls of metallurgical furnaces. The aim of the invention is to increase the durability of the gunning coating by improving the adhesion of the applied refractory material and stabilizing the combustion process. Natural gas is pre-mixed in a 1: 1 ratio with compressed air; oxygen is introduced into the pneumatic track before the gunning nozzle to intensify the process of oxidizing gaseous fuel. The coefficient of oxygen consumption in relation to the gas-air mixture is maintained in the range of 0.1-0.4. 1 dw., 2 tab.

Description

The invention relates to metallurgy and can be used in metallurgy and machine-building enterprises when applying coatings on refractory walls of metallurgical furnaces.

t The purpose of the invention is to increase the resistance of the sprayed coating by improving the adhesion of the refractory material being applied and stabilizing the combustion process of the fuel.

The drawing shows a device for implementing the proposed method.

According to the proposed method, natural gas is pre-mixed in a 1: 1 ratio by volume with compressed air, oxygen is introduced into

the pneumatic track immediately before the application of the refractory coating, while the coefficient of oxygen consumption relative to the gas-air mixture is maintained in the range of 0.1-0.4.

After the natural gas is mixed with compressed air in the mixer 1, the gas-air mixture is supplied to the pneumatic track 2 and moves towards the outlet nozzle 3. A bunker 4 is placed along the gas-air mixture path with gunning powder 5 connected to the pneumatic track. After opening the gate, the gunning mass is drawn into the pneumatic track and is fed to the exit nozzle 3. Before the nozzle, 3 gunning tuyeres are arranged through a series concentrically located in the direction of

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about

O1

oh

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In order to produce a left-dangerous gas-air mixture transporting the refractory powder of the inlets 6, oxygen gas is injected under pressure to intensify the process of oxidation of the fuel.

After exiting the guncrete through the nozzle 3, the gas-air-oxygen mixture is ignited. Fireproof mass

5644

plastic state. This ensures their adhesion to the working surface and the acceleration of the process of interaction of particles with refractories. The mass passing through such a torch adheres tightly to the surface being repaired, which is also treated during the coating process.

falls into a hard steady-regulation JQ high-temperature torch. A fireproof high temperature Torch, in which it acquires a state that allows to obtain a high quality coating.

resistant coatings obtained by implementing the proposed method are characterized by increased resistance (especially when used as bonded

The indicated ratio of 1: 1 relates to J5 yush of its low-melting substances). Besides

c to natural gas with a heat of combustion of 8200-8400 kcal / m and was chosen on the basis that a decrease in gas consumption below the level of air consumption leads to a decrease in the rate and temperature of combustion, an increase in unproductive heat losses due to the fact that at this ratio the combustion of fuel goes from mixed to diffusion.

An increase in the air flow rate with respect to natural gas leads to an increase in the volume of combustion products that cool the combustion zone and lower the temperature of the Torch. In addition, an increase in the air content leads to the plugging of the flame, destabilizing the process of applying the refractory coating. The formation of an explosive mixture is not excluded.

The introduction of gaseous oxygen with a coefficient of oxygen consumption in relation to the gas-air mixture in the range of 0.1-0.4 is due to the achievement of the most optimal resistance conditions of the applied refractory coatings. When the oxygen consumption deviates below the minimum, underburning of the fuel is observed, the process cannot be stabilized, and the torch is controlled, besides (the configuration of the torch is not satisfactory. When the oxygen content increases above 0.4, the torch cools down and clogs it. The coating process becomes unstable.

With deviations from the above parameters, a deterioration in the quality of the applied coatings was observed.

The torch has a uniform temperature throughout the section, i.e. particles uniformly warming up, when the lining of the furnace is reached, they acquire pyro

resistant coatings obtained in the implementation of the proposed method are characterized by increased resistance (especially when used as a bond).

0

five

moreover, by introducing additional oxygen into the pneumatic system under pressure, the refractory mass does not adhere to the walls of the nozzle and pneumatic circuit due to the sharp cooling of oxygen due to the throttling effect.

PRI me R. A method of applying a refractory coating on the working surface of the walls in contact with the molten metal was tested at the DMB-0.5 arc copper-smelting furnace, ICT-6 induction furnaces, ICT-2.5, ILT-1. At the same time, the refractory powder (the binder was made by a low-melting powdered material) was fed into the jet of a pre-mixed gas-air mixture. Oxygen was introduced in the exit zone of the refractory composition to the nozzle. The thickness of the layer of refractory coating applied to the worn surface of the masonry is 15-45 mm. After this, the furnace continued to operate for two days, then the coating was performed again. Thus it was possible to significantly extend the campaign of the furnaces.

As a refractory component, distensylimanite 5 concentrate (fraction 0.05 mm), finely dispersed kaolin clay, chamotte powder — boric anhydride, boric anhydride, talc, sodium trisodium phosphate, technical soda, etc. were used.

The composition of the gunning mass, providing optimal results on the resistance of the gunning coating, wt.%:

0

50

Kaolin clay25-27

Distsensilymanite

concentrate fraction n.b.

0.05 mm58-62

Sodium tripolyphosphate 6-8

Titanium dioxide -2 -2

Boric anhydride1 -2

Technical soda3-5

B Table 1 shows the results when applying a coating to the ICTT-6 induction furnace lining.

Table 1

Note. Coating time - 10 min.

Based on the theoretical data and carried out coating tests with different ratios of compressed air and natural gas, which were previously mixed in the mixer, it is clear that a 1: 1 ratio for air and gas is optimal both in terms of durability and adhesion improvement. bridges of the applied coating.

However, when applying a refractory coating in the flame of the gas-air mixture with a given component ratio, fuel underburning is observed, the process cannot be stabilized, and the flame is not controlled, and the configuration of the flame is not satisfactory.

To eliminate these drawbacks, which affect the quality of the applied coating, gaseous oxygen is introduced into the pneumatic track at the exit just before the application of the refractory coating.

In order to determine the optimal oxygen consumption ratio in relation to the gas-air mixture on the ICT-6 induction furnace, a flame gunning of the lining was performed at various oxygen consumption and an assessment of the quality of the applied coating.

The test results are given in

Table 2.

table 2

IMECHANE Ratio

air

eleven

Claims (1)

By pre-mixing natural gas with air with the introduction of oxygen at the exit of the pneumatic track in the given optimal ratios (Table 1.2), a short high-temperature flame is obtained. As a result of this organization of the combustion process, the rate of combustion of the fuel is almost the highest regulated. Particles, the passage of such a torch, quickly and uniformly heated, acquiring a pyroplastic state. The durability, adhesion and thickness of the applied coating are proportional to the quality of processing in the high-temperature flare. Invention Formula 40 five 0 five The method of applying a refractory coating, which includes supplying a mixture of gaseous fuel and powdered refractory materials by compressed air to compressed air to the gunning nozzle, supplying oxygen with an external jet, with respect to the mixture, mixing them, heating the powdered refractory materials and feeding them in the flame to the lining furnace, characterized in that, in order to increase the resistance of the gunning coating by improving the adhesion of the applied refractory material and stabilizing the process of burning fuel, as a gas The fuel, natural gas use, premixed with skim air in 1: 1 ratio, and the oxygen is introduced in front of the nozzle pnevmotrassu Sprayed lance, wherein the flow coefficient 6 Oxygen 2 S  F oxygen in relation to the mixture of natural gas and air is maintained in the range of 0.1-0.4. Shrunk take it Natural toy