On The Process Innovation And Property Improvement Of Magnesia Carbon Brick

Magnesia carbon brick is a kind of good refractory material. It is widely used in electric steelmaking, converter and refinery furnace. With the development of the steel industry, the requirement of the magnesia carbon brick's performance become higher and higher. Moreover the service time is decreased by carbon oxidized. The development of magnesia carbon brick is restricted by all of them. Research on the process innovation and property improvement of magnesia carbon bricks is needed to do to improve all of that. One model of magnesia carbon brick in one factory is researched on the process innovation and property improvement of the bricks. At first, according to characteristic of the model of magnesia carbon brick made bythis factory, the improvements of the magnesia carbon brick's performance were researched consisting of adjusting the particle size distribution, optimizing the way of pressing, adjusting dosage of the binder for magnesia carbon and adding solid binder power and plasticizers. In addition, the rules of the process innovation of magnesia carbon brick was researched by surveying significant measurements like bulk density, cold compressive strength and bending strength. The microtopography of magnesia carbon brick was researched by optical microscopy and scanning electron microscopy.With the view of characteristic of this model of magnesia carbon brick, Commonly used metallic simple substance antioxidants was added to improve the antioxygenic property. By the test of oxidation resistance of refractories containing carbon, it was found that adding the power of Al could improve the antioxygenic property best, but magnesia carbon brick contain only the power of Al have serious hydration resistance. Adding the powder of Si and Al with the mass ratio 1 to 3 can keep the antioxygenic property and reduce hydration resistance.B₄C powder was added into this model of magnesia carbon brick as antioxidants. The antioxygenic property and slag resistance can be raised several times. The structural features was characterized by SEM and XRD. It was found that the B₄C powder reacted with MgO to form magnesium borate which can prevent the intrusion of oxygen into the magnesia carbon brick.Al₄SiC₄ powder was prepared by vacuum sintering in vacuum sintering furnace. It can reduce carbon which was oxidized. The carbon loss of specimens adding Al₄SiC₄ decreased by 50%⁶0% (1500℃, 6h).The carbon of Al₄SiC₄ became graphitic carbon to resist oxidation. The Al₄SiC₄ decomposed to Al₂O₃ and SiC which reacted with MgO formed magnesium aluminate spinel and forsterite. The protective layer was formed to prevent oxidation.