煤矿井下超细粉尘扩散难抑制、传统降尘剂润湿性差及生物可降解性能差等问题严重制约了矿井粉尘治理效果。针对上述问题，本研究以超细煤尘为主要研究对象，基于表面活性剂复配技术，开发了一种高效、可生物降解的新型降尘剂，并系统探究了煤尘理化特性、降尘配方筛选及工艺参数对降尘率的影响机制。主要研究内容及结论如下：

（1）针对传统降尘剂润湿性差、环境友好性不足的问题，选取14种表面活性剂，通过表面张力、接触角及沉降试验筛选出润湿性能优异的单一表面活性剂，并进行两两复配优化。结合喷雾降尘模拟实验及生物降解性（BOD₅/COD）测试，确定了针对不同煤尘的最佳复配方案：张家峁煤尘采用CDEA:SAS-60 = 4:1（质量分数为0.05%），红柳林煤尘采用CDEA:SAS-60 = 3:1（质量分数为0.2%）。红外光谱分析表明：降尘剂作用后煤尘表面含氧官能团吸收峰增强，亲水性提升。

（2）针对我国煤尘种类繁多、变质程度差异大的特点，选取4种不同的煤样，通过工业分析、傅里叶红外光谱、表面电位、接触角及沉降试验，系统分析了煤尘化学组分、表面电位及粒径对润湿性的影响。SPSS皮尔逊相关性分析表明：在显著性水平为0.01下，固定碳含量对煤尘沉降速率及表面电位变化量的影响最为显著。引入粒径变量后，发现煤尘粒径对沉降速率的影响占主导地位，而固定碳含量和粒径共同影响表面电位变化。该研究为不同煤尘的针对性降尘提供了理论依据。

（3）采用所设计的降尘剂，进一步探究了喷嘴参数（孔径、形状）、流体特性（流速、流量）及喷嘴雾化气压对降尘效率的影响。实验表明：①针对超细煤尘，0.5 mm孔径的降尘效果优于0.7 mm和1 mm；②扇型喷嘴的降尘率显著高于圆形喷嘴；③流量1.6 mL时降尘效果最佳；④流速0.5 mL/s~0.55 mL/s为最优范围，过高会导致降尘效果下降；⑤供气压强3 MPa时，降尘率可达80%以上。此外，通过对比SiO₂与煤尘的粘附行为，发现随着粉尘浓度的增加，粉尘采样器采集浓度与实际充入粉尘浓度差距越大。相较于5 μm SiO₂，实际充入的10 μm SiO₂浓度与仪器采集粉尘的浓度之间的差距较大，仪器采集的10 μm SiO₂颗粒数量较少，且易发生团聚现象。再者，高浓度下实际充入的5 μm SiO₂和仪器检测到的粉尘浓度差距较大。揭示了粉尘粘附性对降尘效率的影响机制。

Problems such as difficult to inhibit the diffusion of ultrafine dust in underground coal mines, poor wettability of traditional dust-reducing agents, and poor biodegradability have seriously restricted the effectiveness of mine dust control. In view of the above problems, this study takes ultrafine coal dust as the main research object, develops a new type of highly efficient and biodegradable dust-reducing agent based on the surfactant compounding technology, and systematically explores the physical and chemical properties of coal dust, the screening of dust-reducing formulations, and the mechanism of the influence of spraying parameters on the dust-reducing rate. The main research contents and conclusions are as follows:

(1) Aiming at the problems of poor wettability and insufficient environmental friendliness of traditional dust reducing agents, fourteen surfactants were selected, and a single surfactant with excellent wettability was screened out through surface tension, contact angle and sedimentation tests, and optimized by two-by-two compounding. Combined with the spray dust reduction simulation experiment and biodegradability (BOD₅/COD) test, the optimal compounding scheme for different coal dusts was determined: CDEA:SAS-60 = 4:1 (mass fraction of 0.05%) was used for Zhangjiamao coal dust, and CDEA:SAS-60 = 3:1 (mass fraction of 0.2%) was used for Hongliulin coal dust. Infrared spectral analysis showed that the absorption peaks of oxygen-containing functional groups on the surface of coal dust were enhanced after the action of the dust-reducing agent, and the hydrophilicity was elevated.

(2) Aiming at the characteristics of China's coal dust, which has a wide variety of types and large differences in the degree of metamorphism, four coal samples were selected, and the effects of the chemical components of the coal dust, surface potential and particle size on the wettability were systematically analyzed through the industrial analysis, fourier transform infrared spectroscopy, surface potential, contact angle and settling test. The SPSS Pearson correlation analysis showed that: at a significance level of 0.01, the effect of the fixed carbon content had the most significant effect on the settling rate of coal dust and the amount of change in surface potential. After the introduction of the particle size variable, it was found that the particle size of coal dust had a dominant effect on the settling rate, while the fixed carbon content and particle size together affected the surface potential change. This study provides a theoretical basis for the targeted dust reduction of different coal dusts.

(3) Adoption of the designed dust reducer, the effects of nozzle parameters (orifice diameter, shape), fluid characteristics (flow rate, volumes) and air pressure on dust reduction efficiency were further investigated. The experiments showed that: ① for ultrafine coal dust, the dust reduction effect of 0.5 mm aperture is better than that of 0.7 mm and 1 mm; ② the dust reduction rate of the fan nozzle is significantly higher than that of the round nozzle; ③ the best dust reduction effect is achieved when the volume is 1.6 mL; ④ the flow rate of 0.5 mL/s~0.55 mL/s is the optimal range, and too high will lead to the decrease of the dust reduction effect; and ⑤ when the air supply pressure is 3 MPa, the dust reduction rate can reach more than 80%. In addition, by comparing the adhesion behavior of SiO₂ and coal dust, it was found that with the increase of dust concentration, the gap between the collected concentration of the dust sampler and the actual charged dust concentration was larger. Compared with 5 μm SiO₂, the difference between the actual 10 μm SiO₂ concentration and the concentration of dust collected by the instrument is larger, and the 10 μm SiO₂ collected by the instrument is less and  is prone to agglomeration. Furthermore, the difference between the actual 5 μm SiO₂ concentration and the instrumented dust concentration is large at high concentrations. The mechanism of dust adhesion on dust reduction efficiency was revealed.