油酸甲酯对长焰煤的捕收性能及量子化学计算

Capture performance and quantum chemistry calculation of methyl oleate on long flame coal surface

为了探究油酸甲酯对麻家梁煤矿煤的浮选效果及相互作用机理,采用煤泥浮选试验、红外光谱、润湿热测定和量子化学计算方法,得到油酸甲酯、正十二烷与麻家梁煤矿煤作用前后的红外谱图、润湿热和前线轨道能量、吸附能等参数,研究了这些参数与油酸甲酯、正十二烷捕收性能之间的内在联系以及作用机理。结果表明:相同药剂用量下,油酸甲酯的精煤产率高于正十二烷,节省药剂用量50%以上。油酸甲酯与煤作用后的红外谱图在-OH振动减弱,在-CH3、C-C等疏水基处振动变强,不仅覆盖煤表面含氧官能团,且覆盖后煤表面疏水基团增加,以此提高煤表面疏水性,从而提高浮选效果。油酸甲酯的润湿热远大于正十二烷,且通过量子化学计算发现,油酸甲酯、正十二烷的前线轨道能隙分别为8.45、4.82 eV,油酸甲酯在含硫和不含硫煤表面的吸附能分别为193.50、199.24k J/mol,正十二烷在含硫和不含硫煤表面的吸附能分别为102.49、114.82 k J/mol,故油酸甲酯具有更高的活性,更易在煤表面发生吸附,是一种低阶煤泥浮选高效捕收剂。

In order to explore the flotation effect and interaction mechanism of methyl oleate on coal from Majialiang Mine,the coal slime flotation test,infrared spectrum,wetting heat measurement and quantum chemistry calculation methods were used to obtain the infrared spectrum,moistening heat,frontier orbital energy,adsorption energy and other parameters of methyl oleate,n-dodecane and coal sample before and after the interaction. The internal relationship and collection performance mechanism between parameters and methyl oleate,ndodecane were studied. The results show the clean coal yield with methyl oleate is higher than that of n-dodecane at the same reagent dosage,and the reagent dosage is saved by more than 50%. The infrared spectrum of the interaction of methyl oleate with coal is weakened at-OH,and becomes stronger at -CH3,C-C and other hydrophobic groups,which not only covers the oxygen-containing functional groups on the coal surface,but also increases the hydrophobic groups on the coal surface after covering,so as to improve the hydrophobicity of the coal surface and the flotation effect. The wetting heat value of methyl oleate is much higher than that of n-dodecane,and the frontier orbital energy gaps of methyl oleate and n-dodecane are 8.45、4.82 e V,respectively by quantum chemistry calculation. The adsorption energy of methyl oleate is 193.50、199.24 k J/mol on the surface of sulfur-containing and sulfur-free coal respectively,and the adsorption energy of n-dodecane is 102.49、114.82 k J/mol on the surface of sulfur-containing and sulfur-free coal respectively. Therefore,methyl oleate has higher activity and is more likely to adsorb on the surface of coal. It is a high-efficiency collector for low rank coal slime flotation.