冷冻煤冻融损伤机理与制浆性能

Freezing-thawing Damage Mechanism of Frozen Coal and the Slurrying Performance

为考察冷冻条件对煤样研磨效率及制浆特性的影响,以羊一矿煤、红石湾煤、巴彦高勒尔煤为研究对象,用冷冻、冷冻-解冻、自然冷冻3种方式对煤进行预处理,考察冷冻时间、冷冻温度对煤研磨特性的影响,并进行制浆实验,通过工业CT、显微观察对煤样冷冻结果进行检测与分析.结果表明,煤样冷冻后可磨指数呈增大趋势.煤样在-5℃,24h时,200目过筛率可提高7.29%;煤样在-20℃,96h冷冻时,200目过筛率可提高6.06%.冰升华后诱发的新煤孔间隙和煤水的溶胀脱离,是煤样强度下降、煤粒子细度增加、水煤浆黏度上升的主要原因.煤样冷冻处理后可以降低水煤浆制备的能耗,改善水煤浆的制浆特性.

In order to investigate the effect of freezing condition on coal sample＇s milling efficiency and slurry characteristics,the authors of the article pretreated the coals with three methods：freezing,freezing-unfreezing,and natural freezing to study the influence of freezing time and freezing temperature on the grinding characteristics and did the slurrying experiment and inspected and analyzed the coal sample freezing result with industrial computer tomography and micro examination methods by taking coals from Yangyi coal mine,Red Rock Bay and Bayan Gaoleer as research objects.The result shows that,the grindability index tends to increase after freezing.200 mesh sieve rate can raise 7.29% under the condition of-20 ℃ and 24 h,and 6.06% under-20 ℃ and96 h.The generated coal hole clearance after ice sublimation and coal-water swelling detachment are the main cause of coal sample strength reduction,coal particles increasing,and coal water slurry viscosity rising.The coal sample after freezing treatment can reduce the energy consumption of coal water slurry preparation and improve its slurry character.