高灰中煤重选抛尾—浮选联合提质工艺研究

发布时间：2018-08-22 14:40

【摘要】：我国肥煤和焦煤资源极度紧缺,在稀缺煤资源极度紧缺的背景下,每年仍有大量的稀缺炼焦煤中煤作为动力煤使用,造成了资源的极度浪费。论文以钱家营矿浮选中煤为研究对象,最终提出了适合浮选中煤分选的抛尾-磨煤-超声强化浮选工艺流程,旨在为浮选中煤的分选提供新的思路。研究了钱家营选煤厂浮选中煤的煤质特性,得到以下结论:浮选中煤灰分达49.30%,主导粒级为+0.5 mm,产率为32.32%;+0.125 mm粒级产率为80.77%,灰分47.66%,总体粒度较粗。浮选中煤中矸石含量较高,+1.5 kg/L密度级产率为48.62%,灰分71.88%;通过对浮选中煤矿物质组成分析,浮选中煤含有以高岭石为主的粘土类矿物。浮选中煤直接磨矿试验结果表明,-0.045 mm粒级含量随磨矿时间的增加而增加,灰分呈先增加后减小的趋势,但灰分均在57%以上。对螺旋分选机进行处理量条件试验探索,得出随着螺旋分选机处理量的增加,精煤可燃体回收率呈逐渐减小的趋势,灰分呈逐渐升高的趋势。对螺旋分选机进行入料浓度条件试验探究,得出螺旋入料浓度越高,精煤可燃体回收率越低,灰分呈现先降低后升高的趋势。在螺旋分选机处理量0.25 t/h、给料浓度为20%时,可抛除产率49.76%,灰分为69.21%的矸石,浮选中煤灰分从49.30%降至31.24%。对螺旋精煤进行磨矿时间探索,磨煤时间定为2 min、3.5 min、5 min、10 min、15 min,分别对磨后产品进行粒度组成分析,得出随着磨煤时间增加,细粒物料含量越来越多,当磨煤时间为2 min时,-0.045 mm粒级含量为30.18%,当磨煤时间为15 min时,-0.045 mm粒级含量已达到71.46%;对磨后产品进行密度组成分析,得出磨煤时间越长,产品解离越充分,在现场要求的精煤灰分为12.50%时,得到的累计产率大小依次是R15 min(65%)R10 min(61%)R5 min(59%)R3.5 min(55%)R2 min(25%);对磨后产品进行分步释放试验,现场要求精煤灰分为12.50%时,累计产率大小依次为R3.5 min(50%)R5 min(40%)R2 min(33%)R10 min(16%)R15 min(12%)得出当磨矿时间为3.5 min,产品已能满足解离要求。研究了浮选中煤的常规浮选,在单因素寻优的条件试验下,对粗选过程矿浆浓度、捕收剂用量、起泡剂用量、叶轮转速进行条件试验,得出在较优的粗选试验条件下可得到产率为65.68%,灰分为18.18%的精煤。对精选进行捕收剂、起泡剂药剂探索试验,得出在精选较优条件下可得到精煤产率为60.62%,灰分15.63%。常规一粗一精浮选工艺难以达到合格的精煤灰分,增加一段精选(一粗二精)可分选出灰分为12.48%的合格精煤,产率为50.14%。对超声波进行不同频率、超声波加入方式以及处理时间的条件探索试验,得出40 KHz超声波全过程处理效果较好。将超声波全过程处理用于一粗一精浮选工艺中,最终可获得灰分为12.49%、产率为61.75%的合格精煤。通过对超声波处理后的煤样进行SEM扫描电镜分析可知,超声波对煤粒表面清洗作用显著。提出了浮选中煤螺旋抛尾-磨矿-超声波强化浮选提质联合工艺。对该工艺进行了数质量流程计算,并与常规分选工艺进行对比,精煤产率提高约9个百分点,此新工艺不仅可以节省一段精选,而且初步经济效益计算表明,该工艺可为企业增收销售利润。该工艺的提出为高灰浮选中煤分选工艺提供了一条新的思路。
[Abstract]:China is extremely short of rich coal and coking coal resources. Under the background of extremely scarce coal resources, there are still a large number of rare coking coal used as power coal every year, resulting in the extreme waste of resources. The coal quality characteristics of the floatation medium coal in Qianjiaying Coal Preparation Plant were studied and the following conclusions were obtained: the ash content in the floatation medium coal reached 49.30%, the dominant particle size was + 0.5 mm, and the yield was 32.32%; the yield of the + 0.125 mm particle size was 80.77%, the ash content was 47.66%, and the total particle size was coarse. High, +1.5 kg/L density grade yield is 48.62%, ash content is 71.88%; Through analysis of material composition of coal mine in flotation, coal in flotation contains clay minerals mainly composed of kaolinite. More than 57%. Conditional test of screw separator shows that with the increase of screw separator, the recovery rate of combustible substance of clean coal decreases gradually and the ash content increases gradually. When the treatment capacity of screw separator is 0.25 t/h, the feed concentration is 20%, the reject yield is 49.76%, the ash content is 69.21%, and the ash content in flotation is reduced from 49.30% to 31.24%. The analysis of particle size composition shows that with the increase of grinding time, the content of fine material is more and more, when the grinding time is 2 minutes, - 0.045 mm particle size is 30.18%, when the grinding time is 15 minutes, - 0.045 mm particle size is 71.46%; after grinding, the product density composition analysis shows that the longer the grinding time, the more fully the product dissociation. The cumulative yield of refined coal ash is R15 min (65%) R10 min (61%) R5 min (59%) R3.5 min (55%) R2 min (25%) and R3.5 min (50%) R5 min (40%) R5 min (33%) R10 min (16%) R15 m (16%) respectively when the content of refined coal ash is 12.50%. In (12%) obtained that when grinding time is 3.5 min, the product has been able to meet the dissociation requirements. The ash content is 18.18%. The experiment of collector and foaming agent shows that the yield of clean coal is 60.62% and the ash content is 15.63% under the optimum conditions. It is difficult to reach the qualified ash content by the conventional one-roughness and one-stage flotation process. The qualified coal with 12.48% ash content can be separated by adding one-stage flotation (one-stage coarse and two-stage flotation). 50.14%. Through the experiment of different frequencies, adding ways and treating time of ultrasonic wave, it is concluded that 40 KHz ultrasonic wave has a better effect in the whole process of treatment. SEM analysis of the coal samples showed that ultrasonic wave had a significant effect on the surface cleaning of coal particles. A combined process of screw throwing tailings, grinding and ultrasonic intensified flotation and upgrading was proposed. The numerical quality process of the process was calculated and compared with the conventional separation process, the concentrate yield was increased by about 9 percentage points. It not only saves one stage of fine separation, but also provides a new idea for high ash flotation medium coal separation process.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD94

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