难浮炼焦煤泥复配药剂浮选规律及作用机理的研究

Flotation rule and action mechanism of difficult-to-float coking coal slime with compound agent

龙泉选煤厂4#入浮煤泥具有细泥含量及中间密度物含量高、浮选精度差的特点。以该煤泥为研究对象,分别选用典型的非极性、极性捕收剂,对其浮选规律进行了系统的试验研究,并在此基础上将非极性煤油与极性苯甲酸戊酯按不同比例复配,考察复配药剂对该难浮炼焦煤浮选精度的强化作用,并对其作用机理进行分析。试验结果表明,相较于煤油单独作捕收剂,采用煤油-苯甲酸戊酯的复配捕收剂(复配比70∶30)在精煤灰分相近的情况下可将精煤产率提高24.72百分点;相较于单独使用苯甲酸戊酯作捕收剂,浮选捕收性能相当,浮选精度较好,药剂成本比降低30%。机理研究表明,接触角大小按煤油-苯甲酸戊酯>苯甲酸戊酯>煤油的顺序依次降低,说明复配药剂能够更好改善煤样疏水性。分子动力学模拟计算发现,煤简化模型代替龙泉4^(#)入浮煤泥模型与苯甲酸戊酯分子的前线轨道能隙差值E_(LUMO)^(coal)-E_(HOMO)^(amyl·benzoate)小于与正十二烷分子(煤油)E_(LUMO)^(coal)-E_(HOMO)^(kerosene),且根据量子化学计算吸附能大小遵循煤油-苯甲酸戊酯复配药剂>苯甲酸戊酯>煤油。证明苯甲酸戊酯本身就易与煤表面发生吸附,70%煤油-30%苯甲酸戊酯复配药剂在煤表面吸附牢固程度高,两种成分能相互协同,增大煤表面疏水面积,提升浮选效果,同时能够降低选煤厂药剂成本。

The 4^(#)fine coal from Longquan Coal Preparation Plant is of high content of fine slime and intermediate density materials,and poor flotation accuracy accordingly.We conducted flotation tests on this coal slime with typical non-polar and polar collectors.Then,we selected kerosene and the amyl benzoate which were compounded with different ratios;investigated the effect of compound agents in different ratios on the flotation selectivity of 4^(#)difficult-to-float coking coal and its mechanism.The test results indicate that compared with kerosene as collector alone,the compound collector of kerosene and amyl benzoate(70∶30)can increase the concentrate yield by 24.72%under similar concentrate ash content.Compared with using amyl benzoate as collector alone,the flotation collection performance is equivalent,the flotation accuracy is better,and a 30%reduction in reagent cost.Research on the mechanism shows that the contact angle decreases in the order of kerosene-amyl benzoate compound agents>amyl benzoate>kerosene,suggesting that compound agents can better improve the hydrophobicity of the coal sample.Molecular dynamics simulations reveal that the energy gap between the simplified coal model and amyl benzoate molecule E_(LUMO)^(coal)-E_(HOMO)^(amyl·benzoate)is smaller than that between the simplified coal model and dodecane molecule(kerosene)E_(LUMO)^(coal)-E_(HOMO)^(kerosene).The adsorption energy calculated by quantum chemistry follows the order of kerosene-amyl benzoate compound agents>amyl benzoate>kerosene.This demonstrates that amyl benzoate itself is easy to adsorb on the coal surface.The 70%kerosene-30%amyl benzoate compound collector exhibits high adsorption firmness onto the coal surface,and the two components can synergistically increase the hydrophobic area of the coal surface,enhance flotation efficiency,and simultaneously reduce the cost of reagents for the coal.