Slag Resistance of Magnesite-chrome Brick Impregnated with Chrome-bearing Sols

Cr2O3 has eminent slag corrosion resistance. So, the magnesite -chrome brick is thought as an important refractory material used in RH refining furnace in the process of steel-making around the world. After chromebearing sols being prepared by sol-gel method, single sol （ Cr（ OH）3） and mixed sol （ Mg（ OH）2 - Cr（ OH）3） were impregnated into magnesite - chrome bricks by vacuum impregnation. The corrosion resistance of the impregnated bricks to silicon steel slag was studied by porosimetric analysis and fractal dimension calculation. The results showed that the corrosion resistance of impregnated magnesite -chrome brick was better than that of the unimpregnated brick and the brick impregnated by MgSO4 solution, and the one which has surface-treated by Mg（ OH）2 -Cr（OH）3 sol was the best, mainly because of lower apparent porosity, smaller pores diameter and their smoother inner sarface.

Refractories for RH Degassers and Ways of Improving Their Lining Life

This paper attempts to clarify the systematic works of the refractories for the RH degassers and the ways of improving their lining life. It includes ： （ 1 ） types of RH degassers ; （2） the operating conditions of refining and the severely damaged areas in RH degassers ; （3） the reasons why side wall and bottom of lower vessel, throat and snorkels become the severe wear areas are analyzed, such as erosion and abrasion caused by the high circula- tion rate of treated molten steel, thermal and structural spalling by the violent temperature change, high corrosion by the Fe-oxides containing siliceous slag and CaF：riched desulfurization powders attack, degradation of texture by the vaporization of refractory components in vacuum and in oxygen blowing; besides the above men- tioned factors, what other reasons to make the snorkels become the most quick wear elements are also explained; （4） the studies of resistance to refining slags attack and slag penetration and its prevention ; the evaluation of va- rious refractory materials to withstand the attack of slags is based on the experimental results of rotating cylinder method, rotary drum test and induction furnace test, and the phase diagrams analyses; the measures to reduce the slag penetration are discussed, for example the deep of slag penetration can be decreased by reducing the size of brick pores ; （5） suitable refractory materials selection and recent developments for the different severe wear areas in RH, and lining maintenance; （6） refractories for RH to refine silicon steel; （7） the ways of improving RH lining life.