氢化物发生原子荧光法测定钢铁中微痕量碲

doi:10.3964/j.issn.1000-0593(2022)10-3103-06

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Abstract Tellurium was a trace and harmful impurity element in iron and steel materials, which could reduce the mechanical and fatigue properties of materials by causing embrittlement and micro-cracks between crystals, and further endanger the service safety of marine equipment. Therefore, it was important to accurately and quickly determine and control tellurium in steel. The original standard method GB/T 223.55—2008《Iron, steel and alloy—Determination of tellurium content-Oscillo-polarographic method》 was abolished in 2017, with the full international and domestic entry into force of the Minamata Convention on Mercury. Because the above method used the dangerous dropping mercury electrode, which would cause the accumulation of mercury in the local environment, thereby endangering the operator’s health and water environment, the analysis of tellurium in steel urgently needed a more environmentally friendly, accurate and rapid method. Based on the characteristics that tellurium could be reduced to volatile tellurium hydride by new ecological hydrogen, the hydride generation sampling technology was used to separate and enrich tellurium from the matrix solution with high selectivity, and the atomic fluorescence method was used in parallel to determine the trace tellurium content in the steel. The working conditions of the atomic fluorescence spectrometer have been optimized, such as negative high voltage, lamp current, observation height, carrier gas flow, the shielding gas flow. Moreover, hydride generation conditions have been studied, including digestion acid, test solution medium, solution acidity, carrier flow acidity and potassium borohydride concentration. Then, the background interference of steel matrix with coexisting ions such as chromium, nickel, manganese, copper, molybdenum, tungsten, titanium, silicon, and vanadium, and the masking methods were systematically investigated. The optimized condition parameters were as below: negative high voltage of 360 V, lamp current of 70~80 mA, observation height of 7~8 mm, carrier gas flow of 700 mL·min^-1, shielding gas flow of 700~800 mL·min^-1. The test solution medium was 15% hydrochloric acid, the masking was 2% thiourea-ascorbic acid, and the potassium borohydride concentration was 1.5%~2.5%. The 0.080 g steel sample was digested by 3 mL aqua regia at low temperature until completely dissolved. Then 20.00 mL 10% thiourea-ascorbic acid mixed solution was added, and the volume was adjusted to 100 mL with 15% hydrochloric acid. A calibration curve was established with iron the matrix solution based on matrix matching method. The calibration curve was a quadratic equation with a correlation of 0.999. The limit of quantification was 1.25 μg·g^-1, and the relative standard deviation of the determination result was not more than 7%. The determination results of the simulated sample were consistent with the theoretical value, and the bias was better than the tolerance specified in GB/T 223.55—2008. The proposed method has the advantages of sensitivity, accuracy, speed and greenness and could be used for the inspection and control of trace tellurium in steel for marine engineering.

Key words：Hydride generation; Atomic fluorescence spectrometry; Steel; Trace; Tellurium; Masking

Received: 2021-08-09 Accepted: 2022-02-15

ZTFLH:

O657.3

Cite this article:

LIU Pan,DU Mi-fang,LI Zhi-ya, et al. Determination of Trace Tellurium Content in Steel by Hydride Generation Atomic Fluorescence Spectrometry[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2022, 42(10): 3103-3108.

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https://www.gpxygpfx.com/EN/10.3964/j.issn.1000-0593(2022)10-3103-06 OR https://www.gpxygpfx.com/EN/Y2022/V42/I10/3103