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Causes of damage to iron mouth of high carbon ferromanganese furnace and modification of refractory brick configuration
Dec 24, 2018

High carbon ferromanganese hot furnace iron brick is an important part of electric furnace lining, which is responsible for the important task of tapping and plays a vital role in the overall lining life. In recent years, due to the increase in the output of high-carbon ferromanganese hot-melt furnaces, the frequency of use of tapholes has increased, and due to improper use of materials and unreasonable structure, the service life of iron ports has been reduced, so the iron mouth is found and solved. The key to short life of the site is an important way to stabilize the continuous production of high-carbon ferromanganese furnaces.

1. Analysis of the causes of damage to the taphole

Due to the frequent action of rapid cooling and rapid heat in the taphole brick, when the thermal stress generated inside the brick exceeds its structural strength, cracks are inevitable, which provides conditions for the intrusion of liquid metal and slag, and even peeling and cracking, causing local damage. . In addition, the high-temperature slag flowing out of the iron rushes out the refractory material of the iron mouth portion to enlarge the tap hole; when the slag has high viscosity, poor fluidity, and poor slagging, the artificial round steel slag will cause the iron outlet to be below the taphole. The refractory material is subjected to strong mechanical scouring and grooves appear. At the same time, the oxidation of the carbon material, the erosion of harmful gases and moisture, and the dissolution of the alloy to carbon cause the life of the taphole to be shortened.

At present, the commonly used taphole bricks are small in size, and the dosage is generally from tens to hundreds of pieces. Therefore, there are many brick joints in the masonry, and the overall structural strength is low, and the masonry is time-consuming and laborious. In the production of iron mouth gas and smelting materials will cause the expansion of brick joints, so that the bricks loose, and thus the slag iron penetration caused serious damage to the iron joint bricks. In addition, the commonly used iron bricks used to use aluminum silicate materials (such as: high alumina bricks, composite brown corundum bricks, corundum mullite bricks) and carbon bricks. The aluminum silicate material has poor peeling resistance and slag resistance, while the carbon brick has weak oxidation resistance, which is a factor that causes the life of the iron brick to be short.

2 Measures to extend the service life of the tap hole

2.1 Reasonable structural design

The structure adopts a large-diameter semi-graphite carbon-silicon carbide iron brick, which is embedded with a high-conductivity graphite sleeve, thereby reducing the brick joint, effectively ensuring the tightness of the iron mouth portion, and convenient construction, maintenance and replacement.

Large semi-graphite carbon-silicon carbide brick is integrally formed, and is finished by six-face finishing after high-temperature roasting. Its length and width tolerance size is <±3mm, height tolerance size is <±1mm, and then the iron hole is drilled according to user requirements. Angle requirements can be noted). And an inlaid hole with a diameter of φ300mm and a depth of about 500mm is processed at the outer end. The tolerance dimension of the inlaid hole is strictly required. The diameter of the common female hole is not more than 1.0mm of the diameter of the inlaid graphite sleeve, and attention is paid to the graphite sleeve and The inner end contact surface of the parent semi-graphitic carbon-silicon carbide brick should be strictly prevented from causing the graphite sleeve to move outward when the iron is discharged. In order to improve the oxidation resistance of the graphite sleeve, the graphite sleeve was subjected to an oxidation immersion treatment.

2.2 material selection

Large-scale drilled iron bricks are made of semi-graphite carbon-silicon carbide bricks, which have good thermal shock resistance, thermal conductivity, alkali resistance and slag resistance; and high thermal conductivity graphite sleeves due to high thermal conductivity of graphite sleeves. The thermal stress of the brick is reduced, the stress concentration is avoided, the thermal expansion coefficient is low, the volume stability is good at high temperature, and the high temperature strength is high, and the erosion resistance is obtained. The rational configuration of the two materials extends the service life of the iron port.

With the re-modified miner's taphole refractory brick configuration, the normal service life can be extended to more than 2 years. The configuration can effectively reduce the joints of the iron mouth, effectively protect the tightness of the iron mouth, and is convenient for construction and replacement. The application of semi-graphite carbon-silicon carbide brick and high-conductivity graphite sleeve solves the iron viscous iron phenomenon, improves the heat-resistant film performance of the iron-mouth brick, and reduces the cracking and damage of the carbon brick caused by thermal stress.

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