XRF准确测定钼精矿中多种元素分析方法研究

本文详细论述了压片法及熔融片法测定钼精矿的分析条件。其中压片法通过大量采用同一矿区的生产样品经化学定值后作为校准样品建立校准曲线,因此粒度效应和矿物效应基本上可可忽视。文章详细地讨论了元素之间谱线干扰、背景和脉冲高度选择。使用经验系数法校正基体效应,可准确测定钼精矿中的钼、硫、铁、铜、铅、锌等11个元素。在熔融片法主要讨论了元素谱线的选择及其相互之间的干扰。     

X-射线荧光光谱法测定白云石中主次量组分

采用粉末压片x-射线荧光光谱法测定白云石中氧化镁、氧化钙、二氧化硅、三氧化二铝、三氧化二铁和二氧化钛含量。采用校正曲线和基体校准一体的回归方程进行谱线重叠干扰校正和基体效应校正。将白云石样品进行磨细处理,在压片机上制成样片,直接在X-射线荧光光谱仪上按照选定的分析条件,以标准样品做工作曲线,利用工作曲线测定样品含量。通过与国家标准化学法以及熔片法对照,分析结果与标准值、熔片法结果吻合,主含量元素测定结果相对误差不超过10％,同一样品12次测定结果相对标准偏差不超过10％。该方法简便、快速、准确、重现性好。     

X射线荧光光谱法快速测定地质样品中的钼

报道了粉末压片-X射线荧光光谱法快速测定地质样品中的钼,采用经验系数法校正了锶、铀等元素对钼的干扰,分段处理校准曲线使测定结果更准确,同时探讨了制样对测定结果的影响。方法精密度好(RSD为7.91%,n=11),检出限可达到0.48 μg/g。测定过程简单、快速,测定结果与化学值吻合,非常适合地质样品的批量化测定。     

X射线荧光光谱法测定红土镍矿中多种元素

分别研究了采用压片、熔片两种制样方法,用X射线荧光光谱法(XRF)测定了红土镍矿中的9种元素。压片法重点研究了基体效应校正,经散射线作内标和经验系数法校正后,可准确测定除二氧化硅、氧化镁外的7种元素,方法简便、快速;而熔片法着重研究了熔剂和熔样温度的选择,经基体效应校正,各分析元素的结果准确度完全可与化学法相媲美,其相对标准偏差(RSD)在0.50%～3.00%间。     

电感耦合等离子体原子发射光谱法(ICP-AES)测定锌精矿中的多种金属元素

采用高压消解罐消解,王水溶样前处理锌精矿样品,电感耦合等离子体原子发射光谱法(ICPAES)测定了锌精矿标准物质中的多种金属元素的含量,确定了最佳工作条件,选择了最佳分析谱线,并利用元素间干扰校正消除了光谱干扰。实验结果表明,方法线性相关性良好,可同时测定锌精矿中的多种金属元素,方法检出限低,精密度高,分析结果与标准值相吻合,完全满足地矿检测的需求。     

熔融制样-X射线荧光光谱法测定钨精矿中主次组分

本文采用熔融制样-X射线荧光光谱法测定钨精矿中的主次组分(WO_3、Fe_2O_3、MnO_2、CaO、SiO_2)。采用熔融制样,消除样品的颗粒效应与矿物效应;以D.Jongh数学模式对谱线干扰和基体效应进行校正,得到满意的工作曲线。结果表明方法重复性和再现性良好,相对标准偏差为0.154%~1.900%,样品的测定值与认定值基本一致,回收率为92.50%~106.00%。该方法能满足日常分析工作的要求。     

X射线荧光光谱法测定合金中的磷

采用X射线荧光光谱法测定铁基和镍基合金中磷的含量。选用钨的Mα线和钼的Lα线作为测量重叠干扰系数时的参照线。选用合金系统中不存在的钾和钪元素作为校正元素代替钨和钼,这两个元素实际测量的分别是钨的Mα线和钼的Lα线。分别用只含钼和同时含钼、钨的两套标准样品测定了重叠干扰系数,并制定了分析磷的校准曲线。方法应用于标准样品的测定,测定值与认定值相符,测定值的相对标准偏差(n=10)为0.68%。     

熔片X射线荧光光谱法测定锡矿石中八种重金属元素

建立了X射线荧光光谱法测定锡矿石中8种重金属元素Fe,Cu,Zn,As,Sn,Sb,Pb,Bi的分析方法。通过固体纯物质机械混合研磨配制了校准曲线所用的标准样品。采用混合熔剂(Li2B4O7:Li BO2:Li F=10:2.5:1,质量比)加氧化剂Li NO3熔融制备了X射线荧光法所用玻璃片样品(混合熔剂:Li NO3:试样=20:3:1质量比)。在高温熔融过程中,易挥发元素As,Pb一直存在于熔体中,未随熔融时间的增加而出现挥发损失。使用外加内标元素法(In和Co)对元素Sn,Sb,Fe的吸收增强效应进行校正,其它元素使用Compton散射线内标法进行校正。采用干扰曲线法校正Pb Lα对As Kα以及Sn Lβ1背景峰对Sb Lα的谱线重叠干扰。各元素检出限分别为Fe 0.0074%,Cu 0.0043%,Zn 0.0025%,As 0.0036%,Sn 0.019%,Sb 0.010%,Pb 0.0039%,Bi 0.0026%。对国家一级标准物质锡精矿GBW07232和锡矿石GBW07281分别进行10次制样测量,各元素精密度(RSD)在0.11%~18%之间。     

熔融制样–X射线荧光光谱法同时测定铀钼矿中主次成分

采用混合熔剂熔融制样,建立了同时测定铀钼矿中U,Mo,SiO_2,Fe_2O_3,Al_2O_3等的X射线荧光光谱法。以Li_2B_4O_7–LiBO_2作为熔融试剂,NH_4NO_3作为样品的氧化剂,样品与熔剂的质量比为1∶10。除使用铀矿石国家标准物质外,主要选取人工混合校准样品及历年实验室比对的铀钼矿校准样品绘制成工作曲线。采用理论系数法校正样品的基体效应,用Br Kα,Zr Kα,U Lα,Ba Lα,Zn Kα谱线扣除相应元素的谱线重叠干扰。该方法各组分测定结果的相对标准偏差均小于2.0%(n=10);用标准物质验证方法的准确度,测定值相对误差在0.00~8.00%之间,与标准值基本吻合。该法应用于生产实验中,可以满足对铀钼矿准确、快速的测量要求。     

电感耦合等离子体原子发射光谱(ICP-AES)法测定锡精矿中8种杂质元素

应用电感耦合等离子体原子发射光谱(ICP-AES)法同时测定锡精矿中钙、镁、铜、铅、锌、砷、锑、铋8种杂质元素。对锡精矿样品的分解方法进行了合理选择,并对测定时的元素分析谱线、基体及各测定元素间干扰情况等进行了讨论。采用硝酸、盐酸、氢氟酸、高氯酸溶样,盐酸浸取。基体效应较小,各待测元素之间基本无干扰。测定结果与国家标准方法比对结果基本一致,相对标准偏差为1.3%~3.3%(n=11),方法加标回收率为96.0%~105%,能满足实际工作中准确、高效地分析锡精矿中杂质元素的需要。     

Fused glass sample preparation for quantitative laser-induced breakdown spectroscopy of geologic materials

Laser-induced breakdown spectroscopy is a powerful analytical method, but LIBS is subject to a matrix effect which can limit its ability to produce quantitative results in complex materials such as geologic samples. Various methods of sample preparation, calibration, and data processing have been attempted to compensate for the matrix effect and improve LIBS precision. This study focuses on sample preparation by comparing fused glass as a preparation for powdered material to the more commonly used method of pressing powder into pellets for LIBS analysis of major elements in complex geologic materials. Pelletizing powdered material is a common and convenient method for preparing samples but problems with the physical matrix brought on by inconsistencies in the homogeneity, density, and laser absorption, coupled with the chemical matrix problem lead to spectral peak responses that are not always consistent with the absolute concentration of representative elements. Twenty-two mineral and rock samples were analyzed for eight major oxide elements. Samples were prepared under both glass and pellet methods and compared for internal precision and overall accuracy. Fused glass provided a more consistent physical matrix and yielded more reliable peak responses in the LIBS analysis than did the pressed pellet preparation. Statistical comparisons demonstrated that the glass samples expressed stronger separability between different mineral species based on the eight elements than for the pressed pellets and showed better spot-to-spot repeatability. Regression models showed substantially better correlations and predictive ability among the elements for the glass preparation than did those for the pressed pellets.     

钽内标X射线荧光光谱法测定钨精矿中WO_3

提出了以钽为内标波长色散X射线荧光光谱法测定钨精矿中WO3的新方法。以Na2B4O7和Li2B4O7(质量比65:35)的混合物作为熔剂,Ta2O5为内标,同时加入LiNO3为氧化剂,在1200℃下进行熔融制样,最后将本方法应用于实际样品的分析,结果表明,以钽作为内标测定WO3,不仅可以在很大程度上降低实验操作和仪器测量带来的偏差,也可以消除基体效应的影响。方法用于测定白钨精矿和黑钨精矿中WO3,其准确度和精密度优于重量分析法。     

熔融制样-X射线荧光测定钨钼锡矿中的主次成分

采用熔融制样-X射线荧光光谱法测定矿物中的Cu、Pb、Zn、Mo、W、Al、Fe、Si、K、Na、Ti、Ca、Sn等13种主次量元素,采用混合均匀的三混熔剂,以硝酸锂为氧化剂、溴化锂为脱膜剂,进行实验条件优化选择。在650℃下对样品进行预氧化,在1100℃下高温熔融,熔融时间为300 s,最后制成均匀透明,表面光滑无气孔的熔片,以部分国家一级标准物质和自制的钨钼锡标准样品,熔融制片进行测定,线性拟合建立标准曲线,并通过测定谱线选择、基体校正,使钨钼锡的测定范围扩宽,从微量到主量均能进行测定,并且适用于多种不同矿石的测定。样品的组成和含量变化会对分析线强度造成吸收、增强以及谱线重叠的影响,采用经验系数和理论α系数结合来校正其产生的基体效应。相同条件下熔融10个标准样品进行测定,其相对标准偏差(RSD)均小于5%,表明方法的准确度、精密度均满足国家相关质量标准的要求。选用一些含量不同的标准样品进行测定,最终的测定结果与标准值相符,表明方法可用于钨钼锡矿的测定。     

高压覆膜制样X射线荧光光谱法测定多金属矿中的多种元素

采用新的制样技术——高压(1800 kN)覆膜(3.6μm Polyester Film)制样,波长色散X射线荧光光谱测定多金属矿中19种组分。该制样技术对高硅锌矿石GBW07237(SiO282.95%),不加黏结剂,也能制出理想的样片。测定结果显示1800 kN制备样品多数组分的灵敏度、精密度和检出限较400 kN制备的样品有所改善。15个多金属矿标准物质建立校准曲线,使用Rh Kα的瑞利散射线作内标测定Cu、Pb、Zn、As和Rh Kα的康普顿散射线作内标测定Sb、Ag、Sn、Bi、Mo及经验系数法校正基体效应。Cu、Pb、Zn、Mn、As、Sb、Ag、Sn、Bi、Mo的测定结果与化学法相符,可同时分析其中的Cd、S、Fe、SiO2、Al2O3、MgO、CaO、Na2O、K2O等成分。实现了固体直接进样测定多金属矿中的多种元素。高压覆膜制样技术是制样技术的突破,国内外尚未见报道。     

Mineralogical effect correction in wavelength dispersive X-ray florescence analysis of pressed powder pellets

Two methods are utilized to correct the influence of the mineralogical effect on the calibration of elements in geological samples when the pressed powder pellet method is used in wavelength dispersive X-ray fluorescence analysis. The first method involves checking of the 2θ angle for the analyzed element in each sample to correct peak shift and the second method involves replacing the peak intensity with the peak area of the analytical line, so to correct for any shape distortion of the peak. The results were compared with those obtained from the normal method. Major elements in 27 Chinese Certified Reference Materials (CRMs) of rocks, soils and sediments were calibrated with a linear regression curve without theoretical or empirical coefficients. In view of the K values, the calibrations of all 8 elements were improved by the first method and those of 6 elements were improved by the second method. Sulfur calibrations with 4 iron ore CRMs were improved with the use of both methods. The methods have been successfully applied for the analysis of the major elements in limestone ores from different resources of a cement factory.     

光谱法快速测定半钢发热剂中Si、P、S的方法研究

目前,国内没有关于半钢发热剂的国家标准检测方法,只能根据组分范围分别检测各个组分,不仅耗时而且大量化学试剂对环境造成污染。故研究半钢发热剂全组分快速测定方法。文章采用粉末压片制样,研究其制样条件,包括磨样时间、压样时间和压力对测定结果的影响。采用其他方法定值提供的检测样品,作为X-射线荧光光谱法内控标样,文章中基体校正采用经验系数法,通过解谱拟合建立校准曲线,校准曲线建立后仪器建立漂移校正程序。实验结果精密度好,各元素的相对标准偏差在0.15%-1.3%。准确度满足生产需求,实验方法可用于公司快速检测半钢发热剂化学组分。     

Laser-induced breakdown spectroscopy for quantitative spectrochemical analysis of geological materials: effects of the matrix and simultaneous determination

A microscopic laser-induced breakdown spectrometer was used to evaluate the analytical matrix effect commonly observed in the analysis of geological materials. Samples were analyzed in either the powder or pressed pellet forms. Calibration curves of a number of iron and aluminum compounds showed a linear relationship between the elemental concentration and peak intensity. A direct determination of elemental content can thus be made from extrapolation on these calibration curves. To investigate matrix effects, synthetic model samples were prepared from various iron and aluminum compounds spiked with SiO₂ and CaCO₃. The addition of these matrices had a pronounced analytical effect on those compounds prepared as pressed pellets. However, results indicated the absence of matrix effects when the samples were presented to the laser as loose powders on tape and results were compared to certified values, indicating the reliability of this approach for accurate analysis, provided the sample particle diameters are greater than ≈100 μm. Finally, the simultaneous analysis of two different elements was demonstrated using powders on tape.