高频燃烧红外吸收法测定黑龙江典型鳞片石墨矿区浮选流程样品中固定碳

鳞片石墨矿浮选流程样品中的固定碳含量是确定浮选实验条件以及浮选实验所能达到选矿指标的重要依据。由于矿样中的碳酸盐、有机物,以及残留在样品表面的碳酸盐浮选药剂、有机浮选药剂等都会对固定碳含量的测定产生干扰,所以实验先将样品在高温下灼烧除去其中的有机碳,用酸将碳酸盐中的碳转化为二氧化碳挥发除去,然后以铁屑和钨锡混合助熔剂进行助熔,以人工配制的石墨矿校准物质绘制校准曲线,建立了高频燃烧红外吸收法测定鳞片石墨矿浮选流程样品中固定碳含量的方法。对称样量、灼烧温度、灼烧时间、酸处理条件和助熔剂用量进行了优化,确定实验条件如下:称样量为0.040 00～0.120 0g,灼烧温度为470℃,灼烧时间为60min,采用王水(1+4)分解样品中碳酸盐;采用0.5g铁屑和0.8g钨锡混合助熔剂进行助熔。在选定的实验条件下,固定碳质量在1.51～36.24mg范围内与其对应红外吸收信号的积分面积呈良好的线性关系,相关系数为0.999 2,方法检出限为0.005 3%,定量限为0.015%。将实验方法应用于黑龙江典型鳞片石墨矿浮选流程样品的原矿、粗精矿、中矿、尾矿中固定碳含量的测定,测定值与行业标准JC/T ...

Determination of fixed carbon in floatation process samples from typical flake graphite mine area in Heilongjiang Province by high frequency combustion infrared absorption method

The fixed carbon content in flotation process sample of flake graphite is an important basis for determining the flotation conditions and the indexes that can be achieved in flotation experiments. The carbonates and organic matters in sample, as well as the carbonate flotation agents and organic flotation agents remaining on sample surface will cause interference with the determination results of fixed carbon content. Therefore, the organic carbon in sample was firstly removed by burning at high temperature. Meanwhile, the carbon in carbonates was converted into carbon dioxide for evaporation and removal using acids. Then, a mixture of iron filings and tungsten-tin flux was used to facilitate the melting. The calibration curve was established with the artificially prepared calibration materials of graphite ore. The determination method of fixed carbon content in the flake graphite flotation process samples by high frequency combustion infrared absorption was established. The sample mass, burning temperature, burning time, acid treatment conditions and flux dosage were optimized. The following experimental conditions were selected: the sample mass was 0.04000-0.1200g; the burning temperature was 470℃; the burning time was 60min; the carbonates in sample was decomposed using aqua regia (1+4); 0.5g of iron filings and 0.8g of tungsten-tin flux was used to facilitate the melting. Under the selected experimental conditions, the mass of fixed carbon in the range of 1.51-36.24mg had a good linear relationship with the integral area of its infrared absorption signal, and the correlation coefficient was 0.9992. The limit of detection was 0.0053%, and the limit of quantification was 0.015%. The proposed method was applied to the determination of fixed carbon content in raw ores, coarse concentrates, middlings and tailings of flotation process samples of typical flake graphite ore in Heilongjiang Province. The found results were basically consistent with those obtained by the caustic soda asbestos gravimetry in industrial standard method (JC/T 1021.5-2007). The relative standard deviation (RSD, n=6) were between 0.83% and 2.7%. The contents of fixed carbon in three random floatation process samples of flake graphite (raw ores, coarse concentrates, middlings and tailings) were determined according to the experimental method. The determination value was substituted into the law of conservation of mass to calculate the fixed carbon content in the fourth process sample. The determination value of fixed carbon content in the fourth process sample was compared with the calculated value to obtain the back-calculation rate. The results showed that the back-calculation rates for the fixed carbon content in the fourth process sample were between 98.4% and 105%.