It is common to see fire accidents caused by friction during the storage and transportation of wet granulation sulfur. To study the sulfur ignition mechanism under friction conditions, a new rotating test apparatus is developed to reproduce friction scenes at lab scale. A series of experiments are performed under different normal loads. The SEM-EDS and the XRD were utilized to examine the morphologies and compositions of the tested specimens and the friction products. Experimental results show that these two methods are mostly in agreement with each other. The iron-sulfide compounds are produced and the proportion of iron-sulfide compounds is reduced with normal loads increasing, compared to the total number of the friction products. The facts implied by the integration analysis of friction products with the temperature changes of the near friction surface unveil an underlying mechanism that may explain sulfur ignition by friction in real scenarios. The sulfur ignition may be mainly caused by the spontaneous combustion of iron sulfide compounds produced by friction under low normal load with 200N. With the increase of normal loads, the resulting iron-sulfide compounds are decreasing and the high temperature from friction heat begins to play a major role in causing fire.

中文翻译：

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摩擦引起的湿法造粒硫着火机理的实验研究

湿法制粒硫的储存和运输过程中，由于摩擦而引起的火灾事故是很常见的。为了研究摩擦条件下的硫着火机理，研制了一种新的旋转测试设备，可在实验室规模下再现摩擦场景。在不同的法向载荷下进行了一系列实验。SEM-EDS和XRD用于检查试样和摩擦产物的形貌和组成。实验结果表明，这两种方法在很大程度上是一致的。与摩擦产物的总数相比，随着正常载荷的增加，产生了硫化铁化合物，并且硫化铁化合物的比例降低了。摩擦产物与近摩擦表面温度变化的集成分析所隐含的事实揭示了一种潜在的机理，该机理可以解释实际情况下因摩擦而引起的硫点燃。硫点燃可能主要是由于在200N的低法向负荷下摩擦产生的硫化铁化合物的自燃所致。随着正常载荷的增加，生成的硫化铁化合物正在减少，摩擦热产生的高温开始在引起火灾中起主要作用。