Two types of low carbon MgO-C refractories with 6% graphite were prepared using microporous magnesia-rich spinel(5-3 and 3-1 mm)and fused magnesia(5-3 and 3-1 mm)as coarse aggregates,respectively,fused magnesia(≤1 mm)as fine aggregate,magnesia powder(≤0.088 mm),flake graphite powder(≤0.088 mm),metal Al powder(<0.074 mm)as matrix,and phenol resin as binder.After curing at 220 ℃ and coke-embedded firing at 1 500 ℃,the apparent porosity,cold crushing strength,cold modulus of rupture,permanent linear change on heating,thermal shock resistance and slag resistance of the specimens were studied comparatively.The results indicate that:(1)after curing at 220 ℃ and coke-embedded firing at 1 500 ℃,the specimen with microporous magnesia-rich spinel replacing fused magnesia has lower bulk density and higher apparent porosity than the common low carbon MgO-C specimen.After curing at 220 ℃,the specimen with microporous aggregate has lower strength than common low carbon MgO-C specimen,but after coke-embedded firing at 1 500 ℃,it has higher strength and lower permanent linear change on heating;(2)low carbon MgO-C specimen using microporous magnesia-rich spinel to replace fused magnesia aggregate has better thermal shock resistance but worse slag resistance.
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