梅山铁矿爆破粉尘润湿性能关键影响因素

Key influencing factors on wettability of blasting dust in Meishan Iron Mine

以南京梅山铁矿采掘面爆破粉尘为研究对象,对其中亲水性粉尘(HD,可快速沉降水底)与疏水性粉尘(HCD,较长时间浮于水面)进行分离,并利用接触角测定仪测定两者的润湿接触角,对其润湿性进行定量表征;应用激光粒度分析仪、真密度分析仪、X线粉末衍射仪(XRD)及X线光电子能谱仪(XPS)对其理化特性进行全面表征;通过对比二者差异,对影响粉尘润湿特性的关键因素进行讨论。研究结果表明:HCD的润湿接触角远比HD的大,即HCD的润湿能力远比HD的弱;粒径和真密度是影响粉尘润湿性能的关键因素,粒径与真密度越小,粉尘疏水性越强;尘粒表面的化学特性并不是影响粉尘润湿性的关键因素,HCD的表面亲水物相含量比HD的高,HCD表面疏水基团含量比HD的低,与HCD润湿性弱于HD润湿性的探究结果相矛盾;从HCD和HD的粒径分布以及游离二氧化硅体积分数来看,HCD对人体的危害更为严重。

The original blasting dust of Nanjing Meishan Iron Mine was taken as the research object, and hydrophilic dust (HD, sinking quickly to the bottom) and hydrophobic dust (HCD, floating on the surface for a long time) were separated. The contact angles were measured to quantitatively characterize the wettability of HCD and HD. The physicochemical properties were characterized by laser particle size analyzer, true density analyzer, X-ray powder diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS). By comparing the differences in physicochemical properties between HCD and HD, the key factors affecting the wettability of dust were investigated. The results show that the wetting contact angle of HCD is much larger than that of HD, so the wetting ability of HCD is much weaker than that of HD. Particle size distribution and true density are the key physical factors that affect the wetting ability of dust. And the smaller the particle size and true density, the stronger the hydrophobicity of the dust. The surface chemical properties of the dust particles are not the primary factors that affect the wettability of dust. The surface hydrophilic phase content of HCD is higher than that of HD, and the hydrophobic group content of HCD surface is lower than that of HD, which contradicts the conclusion that the wettability of HCD is weaker than that of HD. According to particle size distribution and free silica volume fraction of HCD and HD, HCD is more harmful to the human body.