CZ185694A3 - Method of making repairs of masonry of metallurgical and coke furnaces in heat conditions - Google Patents

Abstract

In the present invention there is disclosed an exothermic mixture for repairing masonry of metallurgical furnaces and coke ovens. The invented mixture is in the form of water suspension, wherein reactive particles of a reducing agent consist of silicon, reactive particles of oxidants consist of iron and manganese oxides and non-reactive particles are represented by aluminium, silicon, magnesium, titanium, calcium, potassium, sodium oxides and admixtures of silicon carbide and/or zirconium silicate. Dry mixture contains 19 to 32 percent by weight reducing agent, 30 to 60 percent by weight reactive particles of oxidants and 13 to 28 percent by weight non-reactive particles. The reducing agent reactive particles are preferably represented by magnesium in the amount of 0.5 to 20 percent by weight or aluminium in the amount of 0.5 to 20 percent by weight or {CaSi} in the amount of 0.5 to 50 percent by weight or {SiZr} in the amount of 0.5 to 50 percent by weight, based on the reducing agent total weight. The reactive particles of oxidants consist of iron oxides in the amount of 15 to 65 percent by weight and manganese oxides in the amount of 35 to 85 percent by weight and optionally of chromium oxides amounting to 0.001 to 25 percent by weight. The non-reactive particles consist of aluminium, silicon, magnesium, titanium, calcium, potassium, sodium oxides, each being present in the amount of 0.5 to 50 percent by weight and silicon carbide amounting to 30 to 70 percent by weight or zirconium silicate amounting to 30 to 70 percent by weight or silicon carbide with zirconium silicate, each amounting to 15 to 35 percent by weight.

Description

(57) The method of repairing masonry in metallurgical and coke ovens consists in spraying on the defects of masonry preheated to a temperature of 200-400 an aqueous exothermic suspension of a defined composition in a layer up to 15 mm, which is heated to the flash point using a burner flame. at least 50,000 kcal / h and the process is repeated until a ceramic layer of the desired thickness is obtained.

o o

tsx spraying (ie burner) with materials,

Method of hot repairs of masonry metallurgical and coke ovens.

Technical field

The invention relates to a method for performing hot repairs of linings of metallurgical and coke ovens, wherein the repairs are carried out by repeated spraying of an aqueous suspension of the exothermic mixture using a burner.

BACKGROUND OF THE INVENTION

There are currently known methods for repairing masonry furnaces using wet or semi-dry spraying techniques for aqueous suspensions without the use of aluminum-based alloys or mixtures thereof. These materials are not exothermic. In use, they are characterized by high productivity, which ensures a short repair time and thus low impact on furnace productivity. However, these materials form a soft, fast-wearing surface when used. whose stability under operating conditions is only about 2-3 months.

Also known is the process described in CZ PV 392-93. This method of repair consists of simultaneously feeding dry matter particles in a burner flame to a synthesis zone preheated to a temperature of at least about 100 ° C. It is a mixture of reactive reducer particles. including silicon and aluminum. a mixture of reactive oxidizing particles including iron, manganese and chromium oxides and a mixture of non-reactive oxide particles. The reactive particles are up to 250 microns in size. The heat consumption per 1 kg of the mixture is 1173.5 Kcal. The synthesis of the refractory material takes place by the reaction between the solid reactive particles of the reducing agents and the oxidizing particles and during the fusion of the reaction products with the unreacted particles of the reactive materials and the non-reactive particles. The burner is used to initiate the exothermic reaction. This method ensures the formation of hard.

depending on the anti-abrasive ceramic surface that is firmly attached to the repaired lining. It requires the use of an energy source (propane-butane and oxygen) in large enough quantities. The mass consumption, due to the limitations of the burner thermal regime and the necessary need to heat the material to the high temperatures required for its melting in the small space between the masonry and the burner (150-200 mm), is limited. The productivity of this process is lower than that of wet or semi-dry spraying.

Another method is described in the invention GE 2022829 C3. It is a method of repairing masonry industrial furnaces for hot masonry, without the use of a burner. It consists in applying to the defects of the pre-heated sack by spraying a layer of exothermic water suspension, made up of a mixture of reactive particles of reducing substances, oxidizing substances and non-reactive fillers, which is heated to the flash temperature by masonry heat. as a result of reactions between reactive particles. This method has high productivity and at the same time it provides high strength and stability of the deposited material, which is practically similar to ceramic surfacing. The drawback is the dependence on the temperature of the masonry furnace. The exothermic flash point of their composition is in the mixture and range

750-1000 ° C. The temperature of the masonry when performing the hot repair can vary over a wide range and is reduced to by cooling

4Q0-500 ^o C. Then there is no longer burning of the deposited mass and thus the final phase for defects is melted, especially during repairs of masonry of extreme heating of this method of repair: to synthesis This deficiency is manifested by coke oven chambers. in which the channels cool down rapidly at the time of repair. Repairs have to be interrupted, there is a need to close the furnace in order to obtain the necessary masonry temperature, which leads to reduced production and also to an increase in repair time. The repair performed may have uneven strength and the ability to withstand external influences depending on the course of repair and cooling of the masonry and depending on the terlot difference of masonry.

SUMMARY OF THE INVENTION

These deficiencies are eliminated by the proposed method of repairing masonry metallurgical and coke ovens hot. It consists in that a layer of exothermic water suspension is applied by spraying (ie by spraying of an aqueous suspension) to the defects of pre-heated masonry at 200-400 ° C, with a layer thickness of 1 to 15 mm. 1-5 mm, with a semi-dry layer of 3-15 mra). The layer is heated by a flame of a burner of at least 50000 kcal / hour. Thereafter, the application of the suspension and heating of the deposited layer by means of a burner are repeated until the necessary ceramic surface layer is formed at the defect sites being repaired.

The aqueous exothermic suspension is a particle consisting simultaneously of a reducing agent, reactive particles and non-reactive particles. Preferred is a composition wherein the reactive reducing particles consist of silicon, the reactive oxidizing particles comprise iron and manganese oxides, and the non-reactive particles comprise oxides of aluminum, silicon, magnesium, titanium, calcium, potassium, sodium, silicon carbide, or silicon carbide. or both silicon carbide and zirconium sulfate, wherein the amount of the substances in the particulate mixture is 19-32% by weight of the reducing agent, 30-60% by weight of the reactive particles of oxidizing substances and 13-28% by weight of the non-reactive particles. Particle sizes are up to 250 µm for reactive particles and up to 1000 µm for non-reactive particles.

an aqueous suspension of a mixture of reactive oxidant particles

The reactive reducing agent particles may additionally contain an additional reducing agent which is 0.5-20% by weight of magnesium, or 0.5-20% by weight of aluminum, or CaSi (calcium-silicon alloy) in the amount of 0, Or SiZr (silicon-zirconium alloy) in an amount of 0.5-50% by weight of a reducing agent.

The mixture of reactive oxidant particles consists of 15-65% by weight of iron oxide and 35-85% by weight of manganese oxide.

The mixture of reactive oxidant particles may additionally consist of chromium oxides in an amount of 0.001-25% by weight of the mixture.

The mixture of non-reactive particles consists of oxides of aluminum, silicon, magnesium, titanium, calcium, potassium and sodium, each in an amount of 0.5-50% by weight and silicon carbide in an amount of 30-70% by weight or zirconium (ZrSiCti) in an amount of 30-70 wt.% or silicon carbide (SiC) with zirconate. each in an amount of 15-35% by weight of the composition.

The use of a heat source of the specified power ensures the initiation of exothermic reactions and the heating of the masonry and allows a quick repair to be carried out independently of the temperature of the masonry being repaired. The method allows the combination of high productivity, which corresponds to wet and semi-dry sputtering with aluminosilicate materials with high strength and anti-abrasiveness of the ceramic flame repair process. In contrast to 392-93), the use of the minimum application of the invention since the flame spraying of the CCZ PV burner is only occasional energy and oxygen. <GE 2022829

C3) on and characterized

In contrast, the method is more versatile and does not depend on the temperature of the masonry. This field of application of this method and enhances the quality due to the stabilization of the temperature conditions and their repair time as well, since the required heating does not extend the repair as a synthesis. Reduces intermittent repairs to masonry furnace surfaces.

Using a wet for cold spraying a thin layer of 3-5 mm thick stabilizes the masonry before further erosion. The defect is not completely filled in this way. For the repair of large defects, it is therefore necessary to use the technology of semi-dry spraying of exothermic suspensions, which, with the use of a burner, provides the possibility to quickly repair significant defects.

The proposed method of repairs can be used for repairs of cracks, debris and other defects of fireproof ceramics. It mainly concerns repairs of masonry metallurgical and coke ovens.

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DETAILED DESCRIPTION OF THE INVENTION

Example g.1;

For the repair of masonry heating verticals of coke oven chambers the mixture was used:

% by weight in the dry mixture

Si 25 MnO 5 Mn02 20 May Ρθ2θ3 25 Cr2 03 ff SiO2 5 AI2O3 3 MgO 3 CaO 2 TÍO2 1 K2O 1 At ₂ 0 1 ZrSi O4 4

Si

MnO

The mixture was applied as an aqueous suspension by spraying (semi-dry spraying) to the defect site, preheated to 400 ° C. The thickness of the deposited layer was about 10 mm. The layer was heated with a burner flame of 50,000 kcal to a flash point of 900 ° C. After reaction and remelting of the layer another layer was applied in the same way, about 10 mm thick. It was heated by the burner flame to 800 ° C. After firing and melting and repeating the whole process three more times, a quality masonry repair was achieved.

Example # 2 =

For the repair of masonry heating verticals of coke oven chambers the mixture was used:

% of dry mixture 3

5 ό

MnOz 20 May Fe203 26 Cr203 WITH Si0 ₂ 5 AI2O3 3 MgO 3 CaO 2 T1O2 1 K2O 1 At ₂ 0 1

An aqueous suspension was prepared from this mixture by mixing the powder suspension with water. The amount of water used was 40 liters per 100 kg powder mixture. The aqueous suspension was then sprayed (wet sprayed) onto the defect site preheated to 200 ° C. The thickness of the deposited layer was about 3 mm. The layer was heated with a flame of a burner having a power of 50,000 kcal to a flash point of 100 ° C. After the reaction was completed and the layer was remelted, another layer of about 5 mm thickness was applied in the same manner. It was heated by the flame of the burner to S00 ° C. After ignition and remelting, a quality masonry repair was achieved.

Claims (6)

Patent claims Method for repairing masonry metallurgical and coke ovens, characterized in that a masonry defect preheated to a temperature of 200-400 ° is sprayed with an aqueous exothermic suspension in a layer of 1 to 15 mm, the layer is heated to the flash point using a burner flame of at least 50,000 kcal / h and the process is repeated until a ceramic surface layer having the desired thickness is obtained. The method of claim 1, wherein the aqueous exothermic suspension is concurrently consisting of silicon, ironsulfate, wherein the aqueous suspension of a mixture of particles, reactive particles of a reducing agent, reactive particles of oxidizing substances comprising iron oxides and manganese, and non-reactive particles containing oxides of aluminum, silicon, magnesium, titanium, calcium, potassium. sodium, silicon carbide or ironsulfate or silicon carbide as well as the amount of substances in the water-free particle mixture is 19-32% by weight of the reducing agent. 30-60% by weight of the reactive particles of oxidizing substances and 13-23% by weight of the non-reactive particles and particle sizes are up to 250 µm for the reactive particles and up to 1000 µm for the non-reactive particles. The method of claim 1 reactive reducing agent particles. which is magnesium in aluminum in an amount of 0.5-20 0.5-50% by weight, or SiZr reducing agents. 2. distinguish it. and additionally contains an additional amount of 0.5-20 wt.%, or CaS i in an amount of 0.5-50 that the blend is reduced. or amount and weight% The process according to claims 2 and 3, characterized in that the mixture of reactive oxidant particles consists of 15-65% by weight of iron oxides and 35-35% by weight of manganese oxides. ι s The process according to claim 4, characterized in that the mixture of reactive oxidant particles consists in addition of chromium oxides in an amount of 0.001-25% by weight of the mixture. The process according to claims 2 to 5, wherein the mixture of non-reactive particles consists of oxides of aluminum, silicon, magnesium, titanium, calcium, potassium and sodium, each in an amount of 0.5-50 w / w and silicon carbide. in an amount of 30-70% by weight or of an ironsilicate in an amount of 30-70% by weight or of a silicon carbide with a sulfonate, each in an amount of 15-35 wt.% Of this mixture. *