炼钢厂在浇注某些钢种时经常发生钢包水口絮流现象,经X射线荧光光谱(XRF)半定量分析,水口絮流物是一种以Al2O3、CaO、SiO2、MgO和Fe为主要成分的物质,其化学成分的分析一般采用滴定法、分光光度法或原子吸收光谱法(AAS)等,这些方法操作相对繁琐、流程长.采用Li2B4O7-LiBO2混合熔剂(m∶m=67∶33)按稀释比为1∶12.5的比例进行熔融制样,加入0.15 g NH4I脱模剂,消除了样品的矿物效应,降低了基体效应的影响;选择与水口絮流物基体相似的矾土、莫来石、焦宝石、高炉渣等标准样品及用这些标准样品按不同比例混合配制的校准样品绘制校准曲线,解决了水口絮流物没有标准物质的难题;以经验系数法校正基体对分析线光谱强度的吸收-增强影响,校准曲线的相关系数均大于0.998 9,建立了熔融制样-X射线荧光光谱法同时测定钢包水口絮流物中Al2O3、CaO、SiO2、MgO和总铁(TFe)含量的分析方法.各组分方法检出限为0.009％～0.014％.选取同一水口絮流物试样,按实验方法测定,各组分测定结果的相对标准偏差(RSD,n=10)均小于3.0％.分别采用实验方法与标准方法GB/T 5069-2015测定2个水口絮流物试样,两种方法的差值均小于标准方法GB/T 5069-2015 的允许差.
Determination of 5 components in ladle nozzle flocculation by X-ray fluorescence spectrometry with fusion sample preparation
The phenomenon of flocculation at ladle nozzle often occurs during the pouring of certain steel grades in steel-making plants.The semiquantitative analysis by X-ray fluorescence spectrometry(XRF)in-dicated that the nozzle flocculation was mainly composed of Al2O3,CaO,SiO2,MgO and Fe.The chemi-cal composition analysis usually adopts titration,spectrophotometry or atomic absorption spectrometry(AAS),and so on.However,these methods have some disadvantages such as complex operation and long procedures.The sample was prepared by fusion method with Li2B4O7-LiBO2 mixed flux(m∶m=67∶33)and dilution ratio of 1∶12.5,and 0.15 g of NH4I was added as release reagent.The mineral effect of sam-ple was eliminated,and the influence of matrix effect was reduced.The certified reference materials such as bauxite,mullite,pyroxene,and blast furnace slag,which have the similar matrix with ladle nozzle floc-culation were selected.Then the calibration curves were drawn with these certified reference materials and the calibration samples by mixing these certified reference materials in different proportions,solving the problem that there was no certified reference material of ladle nozzle flocculation.The absorption enhance-ment effect of spectral intensity caused by the matrix was corrected with empirical coefficient method.The correlation coefficients of calibration curves were all greater than 0.998 9.The analysis method for simul-taneous determination of Al2O3,CaO,SiO2,MgO,and total iron(TFe)in ladle nozzle flocculation was established by XRF with fusion sample preparation.The limits of detection were between 0.009％and 0.014％.One ladle nozzle flocculent sample was determined according to the proposed method.The rela-tive standard deviations(RSD,n=10)of determination results were all less than 3.0％.Two ladle nozzle flocculent samples were determined respectively by the proposed method and GB/T 5069-2015,and the differences of the two above methods were all less than the tolerance of GB/T 5069-2015.
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