Research On The Preparation Of The Denaturant Based On The Used MgO-C Brick And Dissolution Kinetics In The Final Slag Of Steel-making

The wasted magnesia-carbon brick a high content of MgO and C, which isrequired for the final slag modifier main components. Thus, this study is recycling ofthe wasted magnesia-carbon brick and take advantage of MgO and C. In this study,we make experiments to optimize the ingredient composition of modifier, whilerevealing its dissolution mechanism in the final slag.Finally, comparing themodification effects of the modifier of the wasted magnesia-carbon brick as rawmaterial and WuGang’s modifier, obtaining the effect of restructuring of the modifierof the wasted magnesia-carbon brick as raw material. Then finally design the modifierthat using the wasted magnesia-carbon brick as raw materiel, which compliant thechemical composition, physical and chemical properties of the required modifier.Optimizing the composition ratio of Modifier’s result shows:(1)Compared with the particle size of0.1~1mm of the wasted magnesia-carbonbrick, particle size less than0.1mm of MgO content of recycled materials is reducedby13%, carbon content increased by7%.(2)A modifier is mainly composed of the used magnesia-carbon brick andmagnesite, and it’s intensity increases with the increase of the water(5~10%); it’sintensity decreases with the increase of adhesive(0.1~0.2%), but the intensity is notchange with the further increase(0.2~0.3%) of adhesive; it’s intensity increases withthe decrease of the recycled material(60.2~56%) and decreases with the increase ofthe recycled material(56~47%).(3)The optimized formula for the preparation of wasted magnesia-carbon brickbased slag modifier is25.7%of magnesite,60.2%of wasted magnesia-carbon bricks,10%of flake graphite,10%of water and0.1%of binder.Dissolution mechanism and effect of the modifier in the final slag shows:(1)Relationship between the same size magnesia raw materials with the final slagreaction rate: magnesite> central of the magnesia-carbon brick> the lower part of themagnesia-carbon brick. In the sample of taken by1min, there are still about0.2×0.3mm hydroxide particles exist, but there are less than0.01×0.01mm ofmagnesite particles in the slag.(2)Combined dissolving mechanism of magnesia raw material and a steel modifier’s TGA, we can know a modifier based of the wasted magnesia-carbonbrick’s dissolution mechanism in the slag as follows: the gas thermal decompositionfrom magnesite make modifier burst, so recycled material accumulate blockssubmerged in the final slag. Recycled material and slag react gas, further bursting itinto different sized particles of recycled materials. Then recycled materials graduallydissolved magnesium oxide, and these different particle size and microstructure ofmagnesium oxide have different reaction speed and mechanism in the slag. Part of thecrack magnesium particles, which are more vulnerable to erosion and continuous tocleave small particles reacting with the slag, to increase the reaction rate. While alarger portion size, better activity and microstructure of magnesium oxide particlesmore complete, final slag react with the surface, constantly dissolve and diffuse intothe slag, and gradually to the reaction inside the particles.(3)The effect of a steel modifieris a slightly is as the same as a modifier ofexperiment, they make the content of MgO upgrade2%and the content of FeO lower5%. And make the modified slag’s high temperature viscosity increased about0.25Ps.s. When and its crystallization temperature than a steel modified high dose of about15℃, while viscosity and high crystallization temperature, is conducive to slagsplashing reformer furnace slag is splashed walls, easy to quickly condense on thewalls of the furnace.