机械力作用诱导硫化矿石自燃的微观机理

Microscopic mechanism of mechanical forces to induce spontaneous combustion of sulfide ores

为揭示不同强度的机械力作用对硫化矿石自燃的影响机理,从某高硫矿山采集具有代表性的硫化矿样,在室内开展硫化矿石的机械球磨实验。联合运用扫描电镜(SEM)、X线衍射(XRD)等测试技术表征矿样在经历100,200,300,350,400和450 r/min等转速表征的不同强度的机械力作用下的表观形貌、微观结构等的演变规律;进一步开展矿样在不同强度的机械力作用下的恒温恒湿氧化实验,并对比各个矿样的氧化质量增大率。研究结果表明:硫化矿石在经历不同强度的机械力作用后,形成细小的细微颗粒并发生集聚效应;随着转速提高,硫化矿石的晶格畸变率增大,晶粒粒度降低,氧化速率明显加快。这表明硫化矿石在外界不同强度的机械力作用下,其化学反应活性增强,更加容易发生氧化自热,进而在一定环境条件下引发自燃火灾。

In order to understand the essential mechanism of mechanical activation for spontaneous combustion of sulfide ores, a typical sample was obtained from the sulfur-rich mine to make the mechanical activation experiment. The surface morphology and microstructure of samples activated at different mechanical powers（100, 200, 300, 350, 400, 450 r/min） were characterized by scanning electron microscopy（SEM） and X-ray diffraction（XRD） analysis. Further oxidation experiment was made at constant temperature and humidity, and the oxidation mass gain rates of the activated samples were compared. The results show that small particles and agglomeration effects are formed after sulfide ores undergo mechanical activation by different mechanical powers. The lattice distortion of sulfide ores increases and the domain size reduces, and the oxidation rate accelerates. Sulfide ores are prone to oxidation after mechanical actions by the increased activation, which leads to spontaneous combustion under appropriate conditions ultimately.