Wet-process spray-coating material for lining of upper shaft of blast furnace, application of wet-process spray-coating material and method for repairing lining of upper shaft of blast furnace

Abstract

The invention belongs to the technical field of repairing of blast furnace linings and particularly relates to a wet-process spray-coating material for a lining of an upper shaft of a blast furnace, an application of the wet-process spray-coating material and a method for repairing the lining of the upper shaft of the blast furnace. The spray-coating material contains the following ingredients in percentage by weight: 4-8wt% of electrically-fused mullite with the granularity of 5mm to 8mm, 10-20wt% of electrically-fused mullite with the granularity of 3mm to 5mm, 15-25wt% of electrically-fused mullite with the granularity of 1mm to 3mm, 15-25wt% of electrically-fused mullite with the granularity of 0.088mm to 1mm, 25-35wt% of electrically-fused mullite with the granularity not greater than 0.088mm, 1-4wt% of silica micropowder, 5-10wt% of activated alumina micropowder and 0.3-0.5wt% of admixture. The service life of the spray-coating material can reach 24 months or more and is greatly prolonged compared with those of spray-coating materials in the prior art; and the spray-coating material has the characteristics of long construction time, excellent medium-temperature physical properties, short baking time and long one-time repair service life, the cost is lower, and the resistance to fracture caused by temperature changes is higher.

Description

technical field [0001] The invention belongs to the technical field of blast furnace inner lining repair, and in particular relates to a wet-sprayed paint for the upper lining of a blast furnace furnace body, its application and a repair method for the upper inner lining of a blast furnace furnace body. Background technique [0002] Blast furnace is a smelting equipment that has been in continuous high-temperature production for a long time. During the long-term operation, the lining of the blast furnace is corroded, spalled and partially or extensively damaged, which affects the normal operation of the blast furnace. In order to achieve the purpose of longevity and high efficiency, wet spraying technology has been widely used to repair the damaged area of ​​the inner lining of the blast furnace during the blast furnace shutdown period when the blast furnace is not in operation. [0003] At present, the lining repair on the upper part of the blast furnace body is mostly use...

AI Technical Summary

Problems solved by technology

[0003] At present, the lining repair on the upper part of the blast furnace body is mostly used as a wet spray coating with pure calcium aluminate cement as a binder and mixed with water. Although it is widely used, there are still some problems: 1. Introduced in the material CaO, easy to mix with Al in the material 2 o 3 , SiO 2 The reaction produces eutectic material, which leads to the reduction of material performance; 2. The thermal performance of the material is not good, and the erosion resistance is poor; 3. The construction time of the material is not long enough, generally not more than 1h, and the details of the construction process are required to be controlled very strictly , prone to problems; 4. The baking time of this spray paint is long, and there is a possibility of bursting during the baking process; 5. The service life is not long, generally maintained at 8 to 10 months

Chinese invention patent CN 105110800 A discloses a wet-process coating for the upper lining of the blast furnace body, which can solve the problems existing in the prior art to a certain extent, and initially achieve the above-mentioned technical effects, but it still has the following deficiencies: 1 ) A large amount of bauxite is used in the spray paint formula, and the content of iron oxide in bauxite is relatively high, which is easy to be eroded by reduction reaction with CO in the blast furnace under high temperature environment, which limits the lining of the upper part of the blast furnace furnace. Service life; 2) The coating formula uses high-priced raw materials such as fused corundum and SiC, which leads to an increase in its cost. At the same time, SiC is easily converted into volatile under the conditions of ultra-high temperature and low oxygen partial pressure in the blast furnace. SiO causes rapid oxidation and corrosion, which in turn affects the service life of the blast furnace lining; 3) The coating formula contains various aggregates such as alumina, fused corundum and silicon carbide, and its expansion and contraction rates are inconsistent when the temperature changes, which is easy to Causes cracking of the blast furnace lining made of it

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