Co-carbonization of Two Weakly-caking Coals with a Fat Coal or Two Pitches

Abstract

The blends of two weakly-caking coals (D1 and D2) with a fat coal or petroleum pitch or coal tar pitch in different proportions were co-carbonized at 3 ı C/min up to 1000 ı C in an experimental 1-Kg coke oven. Coke particulate size, micro-strength, and crushing strength were measured, respectively. Optical textures were watched under a polarized microscope. It was shown that, except for coke yield, blends with coal tar pitch had the best coke micro-strength, cracking strength, and >0.8 mm coke lump yield. Fat coal produced fine-grained mosaics, and weaklycaking coals were mainly fusinite and fragments. Petroleum pitch was coarse-grained mosaics, and coal tar pitch was chiefly flow or domain textures. Independent optical textures were observed in cokes. There existed evident borders between the two contact optical textures that were produced by different components, and a few phenomena that domain or flow textures penetrating into fusinite appeared in the blends. It seemed that coal tar pitch was the best for blending with weakly-caking coal for producing high quality cokes.