Ọ na-ezo aka na ngwaahịa corundum na-acha ọcha na nha nha nke sitere na 0-1mm, 1-3mm, 3-5mm, 5-8mm, 100 # - 0, 200 # - 0, na 320 # - 0. Nnukwu corundum ọcha dị elu. A na-ebuga ebe a na-amụ ihe na-agbaze na ngalaba ụlọ ọrụ mmepụta ájá, nke a na-egwepịa ya ...
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