选煤厂介耗分析--—论文.doc

中国矿业大学 20 11届本科生毕业设计第1页专业英文翻译中国矿业大学中国矿业大学 20 11届本科生毕业设计第2页毕业设计英语翻译姓名: 学号: 学院: 应用技术学院专业: 矿物加工工程翻译题目: 选煤厂介耗分析指导教师:职称: 讲师中国矿业大学 20 11届本科生毕业设计第3页英文原文 An analysis of medium losses in coal washing plants Abstract A major operating cost in dense-medium separation is in replacement of lost medium solids. The loss of medium solids, being costly, plays a crucial role in determining the economics of any preparation operation. Coal washeries that employ dense-medium cyclones often attempt optimization of the processes by varying the vortex or the spigot diameter and the feed relative density. While these changes help in closer control of the separation process, they also result in medium losses due to changes in the medium split ratio (ratio of the medium flow rate in overflow to underflow). Since medium solids are lost by adhesion to products and as ic separator effluent, the effect of the change in medium split ratio on the drain-and-rinse screens and, hence, the ic separator circuit needs tobe studied. In Tata Steel's coal washeries, at Jharkhand India, which employs primary and secondary dense-medium cyclones in series to produce clean coal, middlings and rejects, reducing the relative density of feed medium, had an insignificant effect on the medium split ratio. On the other hand, changing the cone ratio (ratio of the overflow diameter to the underflow diameter) changed the relative density and the flow rates through the cyclone outlets, thus affecting the performance of the ite recovery circuit. A systematic study through laboratory tests and a detailed plant sampling campaign helped in identifying the causes of ite loss. Upon implementation of the mendations, the ite losses decreased, resulting ina saving of approximately US$27,500 per annum. The study also helped in evolving some checkpoints for plant operators for identifying ite losses. Keywords: dense-medium cyclone; ite losses; drain-and-rinse screens; ic separators 1. Introduction Dense-medium (ite in the case of c