高频燃烧红外吸收法测定高硫铜磁铁矿中硫含量

以硫酸钾基准试剂为硫标准绘制校准曲线,建立了高频燃烧红外吸收法测定高硫铜磁铁矿中高含量硫的方法。选定硫质量分数在0.5%~7%之间的5个水平样品(硫的质量分数分别约为7%、5%、2.5%、1.5%和0.5%)进行试验,确定最佳实验条件如下:硫质量分数在0.5%~3%之间时,选择称样量为0.15g;硫质量分数在3%~7%之间时,选择称样量为0.10g;样品加入方式为先将样品放入铺有0.80g铁屑的瓷坩埚中,再覆盖2.0g钨粒。结果表明,硫含量在0.50~12mg之间与其吸光度呈良好的线性关系,线性回归方程为y=5 825.5x+415.75,相关系数R=0.999 9。方法检出限为0.036%,测定下限为0.14%。采用方法对选定的5个水平的高硫铜磁铁矿样品平行测定11次,测得结果与硫酸钡重量法基本一致,相对标准偏差(RSD)均不大于5.0%。方法的重复性限为r=0.032 m+0.036,再现性限为R=0.040 m+0.053。

Determination of sulfur in high sulfur copper magnetite by high frequency combustion infrared absorption method

The calibration curve was drawn with potassium sulphate primary reagent as surfur reference material. Consequently, a method for determination of high content sulfur in high sulfur copper magnetite was established by high frequency combustion infrared absorption spectrometry. The experiment was conducted with five different sulfur level samples of surfur mass fraction in range of 0.5%-7%(the mass fraction of sulfur was 7%, 5%, 2.5%, 1.5% and 0.5%, respectively). The optimum experimental conditions were as follows: sample weight was 0.15 g when sulfur mass fraction ranged from 0.5%-3%; sample weight was 0.10 g when sulfur mass fraction ranged from 3%-7%; the adding sequence of sample and flux in crucible was 0.8 g iron chips, sample then 2.0 g tungsten grain. The results showed that there was a good linear relation between sulfur content in range of 0.50-12 mg and its absorbance. The linear regressive equation was y=5 825.5x+415.75, and correlation coefficient was R=0.999 9. Detection limit of this method was 0.036%,and the lower limit of quantitation was 0.14%. The five high sulfur copper magnetite samples with different sulfur level mentioned above were determined parallelly for eleven times by the proposed method. The results were consistent with barium sulfate gravimetry with relative standard deviation (RSD) no more than 5.0%. The repeatability limit was r=0.032 m+0.036, and the reproducibility limit was R=0.040 m+0.053.