基于X射线衍射的煤炭灰分快速检测方法研究

Study of the X-ray Diffraction-based coal ash rapid determination method

灰分是煤炭工业分析的一项重要指标。针对目前灰分检测多采用人工方式,检测速度慢,难以指导煤炭生产过程等问题,研究了一种基于X射线衍射(XRD)的煤炭灰分快速检测方法。通过对XRD数据定性分析可知,矿物质在XRD曲线上表现为尖峰,煤中有机物在XRD曲线上表现为较宽的驼峰,且煤炭灰分与矿物质峰面积正相关,与有机物峰面积负相关;通过拟合XRD曲线,提取有机物及矿物质峰面积,并建立了两个煤炭灰分预测数学模型。研究结果表明:基于有机峰及矿物峰面积联合的数学模型预测误差更小;采用该模型对三个选煤厂煤样灰分进行预测,预测绝对误差均值分别为0.7301%,0.8099%,0.5015%。该方法可在5min之内获得干燥磨细后的粉末煤样的灰分数据,提高了灰分检测的速度,并且相对于目前应用较广的放射测灰法更加安全,具有工业应用价值。

Ash content of coal is a key indicator in coal proximate analysis.The determination of coal ash is made in most cases nowdays by artificial methods.Such methods are all slow process and the deter-mined data can hardly serve as a guide for coal washing process.To tackle this problem,a XRD-based coal ash rapid determination method is developed.As indicated by qualitative analysis of XRD data,the mineral matters assume a spike form on the XRD curve while the organic matters in coal appear as a hump-formed peak featuring a relatively large width;and the ash of coal is positively correlated with the peak-area of mineral matters and negatively correlated with that of the mineral matters.After determina-tion of the peak areas of mineral and organic matters through fitting of XRD curve,two mathematical models for prediction of coal ash values are developed.Study result shows that the model developed based on the two area features a smaller prediction error;and with the use of the model for prediction of the ash values of the coal samples collected from 3 coal preparation plants,the mean values of the absolute errors of the predicted values are 0.7301%,0.8099%and 0.5015%,respectively.With the use of the XRD-based method,the ash data of dry and ground coal can be obtained within five minutes.Aside its quicker ash determination speed,compared with the radiation method,the XRD-based method has a higher in-dustrial application value for its greater safety.