目前超纯煤制备工艺主要以磨矿加浮选为主,能耗和药耗较大。为优化超纯煤制备工艺,在传统磨矿浮选制备超纯煤的基础上引入了重选工艺,重选先抛尾,有利于减少磨矿和浮选的入料负荷,提高分选效果,同时降低能耗。通过对工艺条件、煤样表面物理化学性质的分析,研究了沁新煤超纯制备工艺条件与可行性。结果表明:与磨矿浮选的制备工艺相比,加入重选后,可预先除去原煤中的高灰细泥,在一定程度上降低了后续实验中设备的损耗;在一段底流口直径为9mm、入料压力为0.1MPa、矿浆质量浓度为50g/L的最佳条件下,原样灰分的质量分数由6.02%降低到4.70%;磨矿实验中,在磨机搅拌转速为700r/min、磨矿时间为45min的最佳条件下,煤样平均粒径D90低至16.20μm,D50低至6.33μm,D10低至2.47μm;结合磨矿前后样品的接触角和SEM-EDS分析得出,煤样磨矿后疏水性降低,矿物质分布较为分散,煤基质与矿物质解离充分;在浮选实验中,在矿浆质量浓度为50g/L、充气量为0.25m3/h、叶轮转速为2400r/min且不添加任何药剂的情况下,经过三次精选的精煤灰分质量分数降低至1.98%,产率为42.35%,经过八次精选的精煤灰分质量分数降低至1.30%,产率为15.75%;在重选工艺对浮选效果的影响实验中得出,与原样直接磨矿相比,在磨矿前加入重选工艺,减少了精选次数,可燃体回收率同比提高了7.02%。

At present, the preparation process of ultra-pure coal is mainly based on grind- ing plus flotation, resulting in large energy and drug consumption. To optimize the ultra-pure coal preparation process, the gravity separation process on the basis of traditional grinding flota- tion for preparing ultra-pure coal was introduced. Gravity separation first throw tail is conducive to reducing the feed load of grinding and flotation, improving the sorting effect and reducing en- ergy consumption. A feasibility analysis of Qinxin coal ultra-pure preparation by analyzing the process conditions and physicochemical properties of the coal sample surfaces was conducted. The test results show that compared with the preparation process of grinding and flotation, the addi- tion of gravity separation can not only remove the high ash and fine slime in the raw coal in ad- vance, but also reduce the loss of equipment in the subsequent tests to a certain extent. The mass fraction of the original sample ash is reduced from 6.02% to 4.70% under the optimal conditions of a underflow orifice to the stage cyclone of mm, and the proper solid ash of the feed and the inlet pressure are g/L and 0.1 MPa, respectively. The results show that the average size of coal particles D , D and D decreases to 16.20 μm, 6.44 μm and 2.47 μm, respectively, in the grinding experiment, under the optimal conditions of mill agitation speed of r/min and grinding time of min. Combined with contact angle and SEM-EDS analysis of the samples be- fore and after grinding, it is concluded that the hydrophobicity of the coal samples is reduced after grinding, and the distribution of minerals is more dispersed, while the dissociation of the coal matrix and minerals is sufficient. In the flotation test, in the conditions that the aerated volume 0.25 m /h, the rotating speed of the vane r/min, the feed pulp mass concentration g/L, the ash content of clean coal is reduced to 1.98%, and the yield is 42.35% after three times of cleaning; after eight times of cleaning, the ash content of clean coal is reduced to 1.30%, and the yield is 15.75% without addition of any chemicals. In experiments on the effect of the gravity separation process on the effectiveness of flotation, it is concluded that the addition of the gravity separation process prior to grinding reduces the number of cleaning and increases the recovery of combustible matter by 7.02% compared with direct grinding of the original samples.