碳化硼粉气流粉碎机理

来源期刊：中国有色金属学报2003年第3期

论文作者：王零森 方寅初 尹邦跃

文章页码：574 - 578

关键词：碳化硼粉；超细粉； 气流粉碎； 球磨

Key words：boron carbide powder; superfine powder; air flow attrition; ball mill

摘    要：对以管式炉碳热还原法制得的平均粒度为20.4μm的碳化硼粉进行了气流粉碎实验。 结果表明： 随着粉碎次数增加， 粒度迅速下降，其平衡粒度达到0.45μm， 远小于相应条件下普通球磨的4μm，振动球磨的2μm； 可避免球磨筒和球的磨损对粉末的污染， 而且能连续作业， 生产率高；对这种原粉粉碎4次是适当的， 可得到约0.6μm的细粉， 进一步增加粉碎次数其粒度降低不大， 但能耗大大增加。 对气流粉碎机理进行了探讨，气流粉碎既有很强的冲击粉碎作用， 又有很强的摩擦粉碎作用， 哪一种机制起主导作用， 取决于进粉粒度： 开始时粉末粒子较粗， 以冲击粉碎为主， 经过数次粉碎之后，粒子较细， 以摩擦粉碎为主； 在粉碎之初， 冲击粉碎对粉末的细化， 即对粉末平均粒度的降低， 起决定性的作用； 随着粉末的细化， 摩擦粉碎对粉末平均粒度降低的贡献增加。

Abstract: The raw powder of boron carbide with a particle size of 20.4μm fabricated by carbon reducing boron oxide in tube furnace was comminuted by air flow attrition. It is concluded that the mean particle size decreases rapidly with the increase of times of air flow attrition. The equilibrium particle size of 0.45μm obtained by it is much less than that by ball mill (4μm) or by vibratory mill (2μm). This method is also a continuous operation process with a higher productivity, and it will not lead to pollution from the wear of balls with jar. The experiment proves that a mean particle size of 0.6μm can be obtained by 4 times attrition, increasing the times further, the particle size decreasing is very limited, but the energy consumption increases much. The mechanisms of air flow attrition are also dealt with. Both impaction and grinding mechanisms are presented in this process. Which one is the dominant one depends upon the particle size of powder feeding into the air flow attritor. At first, the powder is coarser, the momentum of particles is higher, the impaction is the dominant factor; after several times of attrition, the powder is finer, the grinding becomes important. At the same time, a conclusion is also gained: at the beginning the impaction plays an important part in the powder refining; when the particle becomes finer, the contribution of grinding increases.