玻璃纤维膜收集-高频燃烧红外吸收法测定连铸保护渣中游离碳

连铸保护渣中游离碳含量是考核产品质量的重要指标,采用现行的标准方法YB/T 190.6-2014收集游离碳时,在过滤器具中装填酸洗石棉的紧密程度对游离碳测定结果的影响较大,且该过滤材料属易致癌试剂,不宜长期接触.对含有机粘结剂的玻璃纤维膜于450℃灼烧36h以去除膜中的有机物,再在一张玻璃纤维膜上覆盖一层细的三氧化钨粉...

Determination of free carbon in mold flux for continuous casting by high frequency combustion infrared absorption method with glass fiber membrane collection

The content of free carbon in mold flux of continuous casting was an important index to assess the quality of products. During the collection of free carbon by current standard method of YB/T 190.6-2014, the tightness degree of filling pickling asbestos in the filter had a great influence on the determination results of free carbon. Moreover, the filter material belonged to the carcinogenic reagent, and it was not suitable for long-term contact. The glass fiber membrane containing organic binding agent was burned at 450 ℃ for 36 h to remove the organic matters in the membrane. A thin layer of tungsten trioxide powder was covered on one piece of glass fiber filter membrane to quantitatively collect the free carbon particles in mold flux. Then, a determination method of free carbon in mold flux for continuous casting was established by high-frequency combustion infrared absorption with 0.4 g of tin particle and 2.0 g of tungsten particle as flux. The carbon content was traced with certified reference materials of iron and steel. The mixture of 1.08-24.21 mg consisting of spectrally pure graphite powder and 0.5 g of tungsten trioxide powder was parceled with one piece of glass fiber filter membrane. The recoveries of spectrally pure graphite carbon were between 99.1% and 100.4%. Under the selected experimental conditions, the blank value of carbon in whole analysis system was 0.025% (mass fraction, similarly hereinafter). The limit of detection was 0.01%, and the limit of quantification was 0.03%. The proposed method was applied for the determination of free carbon in certified reference material and actual sample of mold flux, and the results were consistent with the certified values. The relative standard deviations (RSD, n=8) of determination results of actual sample were between 0.30% and 1.0%.