A low bulk density, low thermal conductivity permanent lining castable for tundish obtained by adding pearlescent sand

Abstract

The precise control of molten steel temperature in tundish is a key factor to ensure the quality of the cast billets, so it is important to develop permanent lining castables for tundish with low thermal conductivity and bulk density. In this work, the hydrophobic modification of pearlescent sand was carried out with hydrogen silicone oil, and 3% of modified pearlescent sand was added to mullitebauxite castable to realize its low thermal conductivity and light weight. It is found that modified pearlescent sand still has good hydrophobicity at 350 • C, the addition of modified pearlescent sand effectively increases the apparent porosity and reduces the bulk density of the castable. At 1500 • C, the bulk density of modified pearlescent sand-castable is 25.54% less than that of conventional castable.Compared with conventional castable, the mechanical properties and thermal shock resistance of modified pearlescent sand castable are worse, but they are sufficient to meet the use conditions of tundish permanent lining castable. At 600-1000 • C, the thermal conductivity of the modified pearlescent sand castable is about 30% lower than that of the conventional castable, which proves that the addition of modified pearlescent sand can significantly improve the thermal insulation performance of mullite-bauxite castable.

Particle grading effect on properties of reactive MgO‐bonded castables

“…Refractory castables encompass a broad range of materials that have undergone significant advancements, [1][2][3][4] leading to intricate and technically advanced formulations aimed at fulfilling highly demanding and rigorous industrial applications at elevated temperatures. [5][6][7][8][9][10] The primary features of castables consist of a well-chosen combination of raw materials, including aggregates, fillers, binders, and admixtures, [11][12][13][14][15][16][17][18] which leads to a deliberately designed particle gradation affecting the flowability and density of the mixture, [19][20][21][22][23][24][25] alongside the binder that influences both the green mechanical strength and the high-temperature properties, including phase evolutions. 6,[26][27][28] More recently, reactive MgO (RM) is considered as hydraulic binder to prepare castables with superior properties and performance.…”