刚玉和β-SiAlON对MgO基浇注料流变性的影响

Influences of fused alumina and β-SiAlON additions on rheological properties of MgO-based castables

采用65%（质量分数,下同）电熔镁砂作骨料（8-5mm,5-3mm,3-1mm,≤1mm）,27%电熔镁砂粉（≤0.044mm和≤0.074mm）、4%Al2O3微粉和4%SiO2微粉作基质料,以此为基础配方,首先分别用5%、10%、15%、20%的电熔白刚玉粉（≤0.044mm）等量取代同粒度的镁砂粉,然后在加入10%刚玉粉的基础上,分别用2.5%、5%、7.5%和10%的矾土基β-SiAlON（≤0.088mm）取代等量的刚玉粉,分别加水制成两组MgO基浇注料,并采用浇注料流变仪研究了刚玉粉和β-SiAlON粉的加入量对浇注料流变性（扭矩、流动阻力和粘度）的影响。研究结果表明在MgO基浇注料中加入≤10%的刚玉粉时,浇注料的扭矩、粘度和流动阻力较低,流变性较好;加入低于7.5%的β-SiAlON时,对MgO基浇注料的流变性影响不大,但超过7.5%后,浇注料的流变性趋于变差。

Magnesia-based castables were prepared by using fused magnesite as aggregate（8-5 mm,5-3 mm,3-1 mm,≤1 mm）,27% of fused magnesite fines（≤0.044 mm and ≤0.074mm）,4% of Al2O3 ultra fine powder and 4% micro silica as matrix.Based on the formula,5%,10%,15%,20% of fused alumina （≤0.044 mm） substituted respectively the corresponding contents of same sized fused magnesite fines.While 10% of fused alumina was added,2.5%,5%,7.5%,10% of bauxite-based β-SiAlON （≤0.088 mm）substituted respectively the corresponding contents of fused alumina, and appropriate water was added.Two groups of Magnesia-based castables were finally prepared. Influences of fused alumina and β-SiAION additions on theological properties （torque,flow resistance and viscosity） of magnesia- based castables were analyzed by Rheometer. The results showed that when alumina addition was less or equal to ]0% ,the castable performed lower torque, viscosity and flow resistance but better rheological behavior; when 13-SiAION addition was below 7. 5%, theological properties were less effected. However, once the addition exceeds 7. 5% ,the rheological properties tended to degrade.