煤样粒度对煤的视相对密度测定影响探讨

煤是由有机物质和无机物质混合组成,由于自身的特殊性质,影响煤的视相对密度测定因素很多,如样品制备、温度控制、空白试验等。按照GB/T6949-1998《煤的视相对密度测定方法》要求,煤样粒度采用10~13mm,即使严格按照国标制样化验,仍出现化验数据与实际情况不符的现象。大量的对比实验表明:煤样粒度对测试结果影响明显,其中采用4~6mm和6~10mm2个粒级进行煤视相对密度测定实验,结果发现重复性限好。考虑到4~6mm粒度的煤样在涂蜡时容易崩解破裂并易粘蜡屑等缺点,故建议用6~10mm粒度代替国标中的10~13mm粒度进行煤视相对密度的测定。

A Discussion on Impact of Coal Sample Granularity on Determination of Apparent Relative Density of Coal

Coal is composed of organic matter and inorganic matter.Since the particularity of itself,many factors impact apparent relative density determination,such as sample preparation,temperature controlling and blank test etc.According to requirements on GB/T6949-1998 ＂Determination of Apparent Relative Density of Coal＂,coal sample grain size 10～13mm is required,even if strictly in terms of this GB national standard to prepare samples and determine,phenomenon of assay data and practical situation out of line is still existed.A mass of comparative tests demonstrated that the impact of sample grain size on test results is obvious.Among them,test results from two grain size ranges 4～6mm and 6～10mm have good repeatability.In light of the disadvantages of 4～6mm grain size samples are easy to disintegrate and paraffin particles sticking on during paraffining,thus to use 6 ～10mm grain size samples to substitute 10～13mm grain size samples in national standard to determine apparent relative density is advised.