Our company had produced the black corundum by aborative craftwork of fragmentation, sundries cleaning, washing, classifying and made the specification of segment sand are 12mm,13mm,35mm etc, grain-size sand of black corundum is #8#400. The special specification requirement by the customers can also be produced, all kinds of segment sand special use for freeway, airdrome runway, road surface of bridge, wearable and skid-proof ground. The products of all kinds of specification with concentrative grain size distribution and higher standard of internal control of company than international standard are the polishing abrasive materials of excellent quality, having the fine performance of moderate rigidity, fine tenacity, self-sharpness, caking property and durability. The little amount of caloric power produced by grinding will not score the work pieces and not arouse surface discolorations of them; the smooth finish of them will be higher. They are mainly applied to the polishing of surface of metal parts before the electroplating, especially suitable to the polishing finishing of parts of stainless steel, and also applicable to polishing of such materials as optical glass and lumber to make coated abrasive tools of resin, coated abrasive and etc.