Preparation method of MgO-C castable

Abstract

The invention relates to a preparation method of a MgO-C castable, comprising the following steps of: using granulation flake graphite as a carbon source, adding an appropriate additive, uniformly dispersing graphite in a castable, and unconspicuously increasing the amount of water for stirring the castable to finally obtain the MgO-C castable with high carbon content (3.0-7.3 wt%), high strength, uniform and compact structure and excellent slag resistance. The raw materials used contain: by weight, a fused magnesia aggregate consisting of 14-22 parts of an aggregate 5-3mm, 10-20 parts of an aggregate 3-1mm and 12-16 parts of an aggregate 1-0.088mm; 29-33 parts of a fused magnesia fine powder with its particle size being less than 0.088mm; 10-18 parts of granulation graphite; 2-5 parts ofsilicon ash; and an additional additive consisting of 0.7-2.0 parts of an antioxidant, 0.1-0.7 part of a wetting agent and 0.1-0.3 part of a dispersant.

Description

technical field [0001] The invention belongs to the technical field of refractory materials, and relates to a method for preparing an MgO-C castable. Background technique [0002] MgO has the characteristics of high melting point, abundant resources, and strong resistance to slag erosion, and is a cheap and high-quality refractory material. However, due to the large thermal expansion coefficient of MgO, it is easy to be thermally peeled off during use, and has good wettability with molten slag, and the molten slag is easy to penetrate into it to cause damage and peeling of MgO-based materials. For this reason, there are a lot of literature reports: adding Al2O3, SiO2, Cr2O3, ZrO2 and CaO have been modified to achieve good results and have been successfully used in practice. However, compared with MgO-C bricks, these modified MgO-based castables still have a gap in their resistance to slag erosion and thermal spalling. Further studies have shown that adding carbon to MgO-ba...

AI Technical Summary

Problems solved by technology

[0003] When flake graphite is introduced into MgO-based castables, there are two problems: first, the wettability of flake graphite and water is poor, and graphite is introduced into castables, which will As a result, the amount of water added to the castable is greatly increased, making the structure of the castable loose and affecting its high-temperature performance; second, the density difference between flake graphite and fused magnesia is large (the density of flake graphite is less than 1.8g / cm3 , while the density of fused magnesia is about 3.5 g / cm3), when graphite and fused magnesia are introduced into the castable together, it will cause particle segregation

The results show that: compared with the carbon-free MgO castable, when 6wt% of the modified graphite is added (the actual carbon content is about 4wt%), the workability of the castable becomes worse, and the amount of water added increases from 4.1wt% to 6wt%; the hot strength of the castable has been improved, but the bulk density, cold strength and other properties are greatly affected

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