ABSTRACT

Around 25 million tons of coal mine waste rock (CMWR) are stored in many places in Morocco due to coal mining activities. As a result, air and water quality of the neighborhood is polluted and large lands are occupied. This study aimed to investigate the use of an integrated and circular approach based on coal recovery and waste rock recycling. More than 30 drill core samples were taken from the big coal dump reaching a depth of 60 m and analyzed to evaluate the chemical composition variability. Froth flotation was used to recover coal particles using diesel as a collector and Methyl Isobutyl Carbinol as a frother, 100 g/t each. The tailings of coal flotation process (CFT) were used to manufacture fired bricks at a pilot scale. The results of this study highlighted the possibility to valorize the whole waste material toward an objective of zero waste in the future. On a basis of 100t feed, (i) 10-15t can be recovered as high-quality anthracite coal with a calorific value over 7500 kcal/kg using flotation processing at a recovery yield over 80%, (ii) 45-60t can be reused as shales for bricks production with a compressive strength over 16MPa, (iii) 20-30t can be reused as aggregates for concrete production with a compressive strength over 20MPa. The remaining material can be reused as sand. The recovered anthracite can be reused to manufacture coal briquettes or used at it is in the thermal power plant next to the dump site.

摘要

由于煤炭开采活动，摩洛哥许多地方储存了约 2500 万吨煤矿废石 (CMWR)。结果，附近的空气和水质受到污染，并占用了大片土地。本研究旨在研究基于煤炭回收和废石回收的综合循环方法的使用。从深度达 60 m 的大型煤堆中采集了 30 多个钻芯样本，并进行分析以评估化学成分的变化。采用泡沫浮选法回收煤颗粒，使用柴油作为捕收剂，甲基异丁基甲醇作为泡沫剂，各 100 克/吨。煤炭浮选工艺 (CFT) 的尾矿用于中试规模生产烧结砖。这项研究的结果强调了对整个废物进行定价以实现未来零废物目标的可能性。以100t进料计算，可浮选回收10-15t为热值7500kcal/kg以上的优质无烟煤，回收率达80%以上；45-60t可作为页岩回用，用于制砖，抗压强度超过16MPa；30-30t可回用为骨料，用于压缩混凝土生产强度超过20MPa。剩余的材料可以作为沙子重新利用。回收的无烟煤可重新用于制造型煤或用于垃圾场附近的火力发电厂。（i）10-15t可通过浮选处理回收为热值7500kcal/kg以上的优质无烟煤，回收率超过80％；（ii）45-60t可重新用作页岩用于抗压强度超过16MPa的砖块生产；（iii）20-30t可重新用作骨料用于抗压强度超过20MPa的混凝土生产。剩余的材料可以作为沙子重新利用。回收的无烟煤可重新用于制造型煤或用于垃圾场附近的火力发电厂。（i）10-15t可通过浮选处理回收为热值7500kcal/kg以上的优质无烟煤，回收率超过80％；（ii）45-60t可重新用作页岩用于抗压强度超过16MPa的砖块生产；（iii）20-30t可重新用作骨料用于抗压强度超过20MPa的混凝土生产。剩余的材料可以作为沙子重新利用。回收的无烟煤可重新用于制造型煤或用于垃圾场附近的火力发电厂。