Abstract Fine powders are generated in large volumes by industrial activities such as mining, metallurgical processing, energy generation and processing of waste. To meet specifications for further use, powder processing such as comminution and size classification are commonly applied. To optimise the design and operation of air-flow based classification processes, continuous on- line, monitoring of variations in dust particle concentration are an asset. This paper reports on the development of a novel ultrasonic measurement system suitable for robust monitoring of air-borne dust concentration variations during the operation of powder classification installations. The system was tested on a pilot-scale classifier designed for air-borne separation and recovery of ultrafine powders from coal combustion fly ashes. The monitoring method is based on a measurement of ultrasonic wave attenuation by particles suspended in the air-flow of the classifier.

中文翻译：

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粉体分级机粉尘浓度变化的超声波监测

摘要 采矿、冶金加工、能源生产和废物处理等工业活动会大量产生细粉。为了满足进一步使用的规格，通常应用粉末加工，例如粉碎和尺寸分级。为了优化基于气流的分类过程的设计和操作，连续在线监测灰尘颗粒浓度的变化是一项资产。本文报告了一种新型超声波测量系统的开发，该系统适用于在粉末分级装置运行期间对空气中粉尘浓度变化进行稳健监测。该系统在一个中试规模的分级机上进行了测试，该分级机设计用于从燃煤飞灰中分离和回收超细粉末。