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Three Basic Properties of Electrofused Zirconium Corundum

Release time:

2021-11-09 10:27

Electrically fused zirconium corundum refractories are refractory products made of materials melted into liquid in an electric arc furnace, then cast and molded in a sand mold, and machined by cutting and grinding after heat treatment. In general, pre-assembly shall be completed before leaving the factory according to the drawings. Compared with ordinary sintered refractory materials: electrofusion products have fully developed crystal form and compact structure, low porosity, high volume density, and have better resistance to physical and chemical erosion in glass furnaces. At the same time, it is less prone to foaming and calculus in contact with high temperature glass liquid, resulting in fewer glass defects and longer service life.

Due to different production processes, fused refractory materials will have obvious characteristics different from sintered refractory materials: bricks have casting mouth and shrinkage cavity, and the chemical composition, crystal phase structure and density of bricks along the casting direction are different. Therefore, it is not possible to simply apply the method of detecting sintered refractories to monitor the quality of fused refractories.

Three basic properties that affect the quality of fused refractories:

Degree of oxidation of molten material

The compactness, binding and uniformity of crystal phase structure

Size and location of shrinkage holes.

Application of fused corundum brick in float glass melting furnace

The glass melting furnace is a thermal equipment for melting glass composed of refractory materials. The service efficiency and service life of glass melting furnace depend on the variety and quality of refractory materials to a great extent. The development of glass production technology depends to a large extent on the improvement of refractory manufacturing technology. Therefore, the rational selection and use of refractory materials is a very important content in the design of glass melting furnaces. To do this, we must master the following two points, one is the characteristics and applicable parts of the selected refractory materials, and the other is the use conditions and erosion mechanism of each part of the glass furnace.

Process Improvement of Electro-fused Zirconium Corundum Pavement Brick

Electrically fused zirconium corundum brick is made of industrial alumina powder and zircon sand (containing 66% of zirconium oxide and 34% of silicon dioxide) melted at high temperature in an electric furnace. After melting, it is cast into a shape (the casting temperature is 1780-1840 ℃), injected into the model and cooled to form a solid close to white. Its petrographic structure consists of the eutectoid body and glass phase of corundum and zirconium clinite, it is a eutectoid body of corundum phase and zirconium clinoptilite phase, and the glass phase is filled between their crystals.

How to overcome the defects produced in the casting and annealing of fused zirconium corundum bricks

Electrofused zircon corundum brick in the production will produce a variety of defects, resulting in the use of poor quality products. The physical and chemical inhomogeneity of zirconium corundum bricks is often the main reason for the defects of the products. Particles that are not melted through in the batch and gas inclusions that have not been discharged from the melt in time are all physical inhomogeneities. The difference in the composition of the melt along the depth of the furnace is a chemical inhomogeneity.

Causes of Serious Erosion of Zirconium Corundum Brick in Glass Electric Melting Furnace

The erosion of fused zirconium corundum brick is mainly divided into physical action and chemical action. Physical action refers to the glass melting furnace wall in the long-term operation process, repeatedly subjected to the impact of rapid cooling and rapid heat, the surface must undergo a contraction of the expansion of the change process. Due to excessive fatigue, the structure of fused zirconium corundum brick is damaged, resulting in increased surface cracks and loose structure. Therefore, under the action of air flow, material and glass liquid washing, cracking and peeling, and this process will be repeated.