Experimental Study on the Slime Flotation of Nanliang Coal Mine with Kerosene/methyl Oleate Compound Collectors
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摘要:
陕西省南梁煤矿现有浮选生产药剂成本较高,占选厂总成本的84.5%;另外试验发现GF、FO等复配捕收剂能一定程度上提高浮选效率,但其药剂用量仍然较高。为了进一步提高浮选效率、降低药剂用量、节约成本、提高经济效益,系统研究了复配捕收剂对煤泥浮选效果。以仲辛醇为起泡剂,煤油分别与正辛胺、正癸酸、十二烷、油酸甲酯复配作为捕收剂,对粒度大于0.0385 mm的煤泥进行浮选试验。结果表明,油酸甲酯与煤油质量比为1∶6时,浮选结果最佳,精煤产率由煤油的43.14%提高到复配捕收剂的61.70%,对应的灰分由9.50%变为9.61%,可燃体回收率由42.98%提高到61.48%。煤油/油酸甲酯复配捕收剂优异的浮选效果可归因于油酸甲酸含氧酯基与煤分子上的含氧官能团作用时较高的润湿热和吸附能、较低的前线轨道能隙,更易吸附在煤表面,提高煤的疏水性。X射线衍射、红外光谱和扫描电镜测试结果表明,与煤泥相比,浮选后的精煤中灰分明显减少,只有少量细泥颗粒附着于煤颗粒表面,说明油酸甲酯复配与煤油是一种理想的煤泥浮选捕收剂。
Abstract:The cost of flotation production reagent is high for Nanliang coal mine of Shaanxi province, accounting for 84.5% of the plant cost. In addition, previous experiments indicated that the compound collectors such as GF and FO could improve the floatation efficiency, but the dosage of flotation reagents was high. In order to improve the flotation efficiency, decrease the dosage of regents, save costs and create more economic values, the effect of compound collectors on coal slime flotation was studied systematically in this work. By using sec-octanol as foaming agent, kerosene mixed with n-octylamine, n-decanoic acid, dodecane and methyl oleate respectively as collectors, the flotation experiments were conducted for the coal slime with particle size larger than 0.0385 mm. The flotation results showed that the compound collectors of methyl oleate and kerosene (mass ratio of 1∶6) exhibited the best flotation effect. The cleaned coal yield increased from 43.14% by kerosene to 61.70% by compound collectors, and the corresponding ash content changed from 9.50% to 9.61%. Meanwhile, the recovery rate of combustible substance increased from 42.98% to 61.48%. The excellent flotation effect of methyl oleate compound collectors was attributed to the higher wetting heat and adsorption energy between the oxyester group of methyl oleate and the oxygen-containing function groups of coal molecules, and the lower frontier orbital energy gap, which was helpful for the absorption on the coal surface and improvement of the hydrophobicity of coal. The results of X-ray diffraction, infrared spectrum and scanning electron microscopy showed that the ash content in the cleaned coal after flotation significantly decreased with only tiny fine mud particles attached on the surface of coal particles, indicating that the combination of methyl oleate and kerosene is an ideal compound collectors for slime flotation.
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Key words:
- coal slime /
- flotation /
- compound collector /
- kerosene
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表 1 煤泥工业分析
Table 1. Industrial analysis of coal samples
/% Mad Aad Vad FCad 4.8 56.06 12.44 26.70 注:Mad、Aad、Vad、FCad分别代表空气干燥煤样的水分含量、干燥煤样灰分含量、干燥煤样的挥发分含量、煤样固定碳含量。 表 2 煤泥筛分试验结果
Table 2. Results of small screening test of slime
粒级/mm 质量/g 产率/% 灰分/% 筛上累积/% 产率 灰分 +0.500 9.96 4.98 50.27 4.98 50.27 0.500~0.25 24.48 12.24 44.87 17.22 43.40 0.25~0.125 20.07 10.04 32.50 27.26 42.36 0.125~0.075 14.09 7.05 29.10 34.30 40.90 0.075~0.045 12.36 6.18 37.76 40.48 37.82 −0.045 119.04 59.52 66.19 100.00 56.06 合计 200 100.00 56.06 -
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