Izitena zobunzima be-mullite ziqulethe i-porosity ephezulu, enokugcina ubushushu obuninzi kwaye ngoko iyanciphisa iindleko zepetroli.
I-refractory mortar luhlobo olutsha lwezinto ezibophelelayo ezingaphiliyo, ezenziwe ngomgubo ezinomgangatho ofanayo nezitena ezifakiweyo, i-inorganic binder kunye ne-admixture.