In order to fully recover clean coal from coking middlings,taking the product of middings of heavy separation sedimentation centrifuge as the study object,the possibility of re-preparation of middings was analyzed by carrying out a series of tests,including screening,comminution,float-and-sink separation,and progressive released flotation experiment.The mineral dissemination characteristics before and after crushing were observed by the polarized microscopy.The experimental results show that the optimum comminution size is 0.3 mm,in this case,the organic matters are liberated well with the inorganic matters,such as pyrite and quartz.However,the clay minerals are not liberated well from organic matters,which may cause a higher ash content for the concentrate during the floatation.The float-and -sink test shows that the theoretical yield of the concentrate is 50.00％ corresponding to the ash content of 11.00％.The rougher-cleaning flotation experiment show that when the dosage of diesel oil is 1 kg/t and the dosage of 2-Octanol is 0.1 kg/t,the ash content of the concentrate is 10.57％ and the yield is 46.47％.%为充分回收炼焦中煤中的精煤,以重选中煤沉降离心机产品作为解离再选试验对象,通过筛分、破碎、浮沉、分步释放浮选试验研究了其再选可能性,并用偏光显微镜观察了破碎前后煤中矿物质的嵌布状态.试验结果表明:该煤样最佳的破碎粒度为0.3 mm,此时,煤样中的有机质与黄铁矿及石英得到有效解离,但有机质与黏土矿物并没有得到明显解离,该连生体易在浮选过程中造成浮选精煤灰分偏高.小浮沉试验表明,当精煤灰分为11.00％时,其理论精煤产率为50.00％.一粗一精浮选试验表明,当柴油用量为1 kg/t,仲辛醇用量为0.1 kg/t时,经一粗一精浮选后可以得到灰分为10.57％,产率为46.47％的精煤产品.
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