Comparison of slag resistance of MgO-CaO-C bricks prepared from low-calcium fused magnesia-calcium sand and high-calcium sintered magnesia-calcium sand

Comparison of slag resistance of MgO-CaO-C bricks prepared by fused magnesia-calcium sand and high-calcium sintered magnesia-calcium sand Yingkou Blue and White Refractories Co., Ltd. Pan Bo Yin Guoxiang Wang Jiandong 1mm fused magnesia and low-calcium fused magnesia-calcium sand (ω(CaO)≈20%) or high-calcium sintered magnesia-calcium sand (ω(CaO)≈50%) are orthopedic. Fused magnesia chrome sand flake graphite, fused magnesia powder as the matrix. Keep the mass ratio of aggregate to matrix at 7:3. The MgO-CaO-C bricks with different CaO contents were prepared by replacing the fused magnesia aggregates with low-calcium fused magnesia-calcium sand or high-calcium sintered magnesia-calcium sand with an addition amount of 30%, 40%, 55% and 70%, respectively. The corrosion resistance of the two kinds of bricks against CaO-SiO2 slag was compared by the rotary anti-slag method, and the residual bricks were analyzed by SEM. Key words: magnesia-calcium sand; slag erosion; dissolution; dense MgO—CaO—C brick is a refractory widely used in various refining ladles such as SKF and LF—VD. When refining stainless steel, the main component of steel slag It is CaO-SiO2 slag. The corrosion resistance mechanism of MgO-CaO-C bricks against CaO-SiO2 slag is: when magnesia-calcium sand is in contact with CaO-SiO2 slag, free CaO reacts with SiO2 preferentially to form high melting point Ca2SiO4 (2130 ℃), which increases the viscosity of the slag, thereby increasing the viscosity of the slag. Prevent further penetration of slag into the interior of the sample.

In order to improve its resistance to low alkalinity CaO-SiO2 slag, researchers at home and abroad are committed to increasing the content of CaO, and the content of CaO in the MgO-CaO-C bricks produced by some companies is even as high as 50% (ω). However, due to the high content of CaO, MgO-CaO-C bricks are easy to hydrate, so good waterproofing measures must be taken, such as vacuum thermoplastic packaging...