针对标准方法不能同时测定煤炭样品中砷、磷和硫含量的问题,提出了题示方法。参考标准GB/T 3058-2019中的前处理方法,在陶瓷坩埚中加入1.5 g艾士卡试剂(由轻质氧化镁与无水碳酸钠按质量比2∶1混合而成)和约1 g煤炭样品,混匀后在上面均匀覆盖额外的1.5 g艾士卡试剂。将坩埚放入马弗炉中,升温至500 ℃灼烧1 h,再升温至(800±10)℃灼烧3 h。灼烧物转移至约30 mL热水中,用20 mL盐酸洗涤坩埚数次。合并上述溶液,用水定容至100 mL,供电感耦合等离子体原子发射光谱仪分析。设置仪器工作参数的射频(RF)功率为1 350 W,雾化气流量为0.45 L·min^-1,辅助气流量为0.2 L·min^-1,冷却气流量为13 L·min^-1,分析泵速为60 r·min^-1,以降低样品溶液盐分及黏度对谱线强度的影响。分别以煤炭标准物质GBW 11115a(砷和磷)和GBW 11101y(硫)为基质,采用标准加入法制作工作曲线,并采用仪器自带软件校正,所得校正曲线可直接用于标准物质和实际样品中砷、磷和硫含量的测定。结果显示:砷、磷和硫校正曲线的线性范围分别为1.20,20.0,28.3 mg·L^-1以内,检出限(3s)分别为0.004,0.005,0.170 mg·L^-1。方法用于煤炭标准物质的分析,测定值均在认定值的的不确定度范围内,测定值的相对标准偏差(n=7)均小于5.0%。方法所得实际样品的测定值和用于检测砷、磷和硫的标准方法GB/T 3058-2019(砷钼蓝分光光度法),GB/T 216-2003(磷钼蓝分光光度法)和GB/T 25214-2010(红外光谱法)的分析结果基本一致。

As to solve the problem that arsenic, phosphorus and sulfur in coal sample could not be determined simultaneously by standard methods, the method mentioned by the title was proposed. With reference to the sample treatment method specified in the standard of GB/T 3058-2019, about 1 g of coal sample together with 1.5 g of Eschka reagent (produced by light magnesium oxide and anhydrous sodium carbonate at mass ratio of 2∶1) was mixed in the ceramic crucible, and extra 1.5 g of Eschka reagent was covered evenly on the above mixture. The crucible was heated to 500 ℃ for 1 h in the muffle furnace, and then heated to (800±10)℃ for 3 h. The burning residues were dissolved by 30 mL of hot water, and washed several times with 20 mL of hydrochloric acid. All the solutions were collected, transferred to a 100 mL-volumetric flask, diluted by water, and analyzed by inductively coupled plasma atomic emission spectrometer. In order to reduce the effect of salinity and viscosity of sample solution on intensities of spectral lines, working parameters of the instrument were set as to 1 350 W of RF power, 0.45 L·min^-1 of nebulization gas flow, 0.2 L·min^-1 of auxiliary gas flow, 13 L·min^-1 of cooling gas flow, and 60 r·min^-1 of analytical pump speed. The working curves were made by the standard addition method with the coal standard substances of GBW 11115a (arsenic and phosphorus) and GBW 11101y (sulfur) as the matrix, and calibrated by the software of the instrument, and the calibration curves were used for determination of arsenic, phosphorus and sulfur in standard substances and actual samples. It was shown that linear ranges of the calibration curves of arsenic, phosphorus and sulfur were found within 1.20, 20.0, 28.3 mg·L^-1, with detection limits (3s) of 0.004, 0.005, 0.170 mg·L^-1, respectively. The proposed method was applied to the analysis of coal standard substances, and determined values were within uncertainty ranges of certified values, with RSDs (n=7) of the determined values less than 5.0%. The results obtained by the proposed method were basically the same with determined values gained by the standard methods of GB/T 3058-2019 (arsenic molybdenum blue spectrophotometry used for determination of arsenic), GB/T 216-2003 (phosphorus molybdenum blue spectrophotometry used for determination of phosphorus) and GB/T 214-2007 (infrared spectrometry used for determination of sulfur).