Institute of Metallurgy of Ural Branch of RAS, Ekaterinburg, Russia:
O. V. Evdokimova, Senior Researcher of Laboratory of Analytical Chemistry, e-mail: evdokimova_olga_@mal.ru
N. V. Pechishcheva, Senior Researcher of Laboratory of Analytical Chemistry
P. V. Zaytseva, Researcher of Laboratory of Analytical Chemistry

Ural Federal University named after the first President of Russia B. N. Yeltsin, Ekaterinburg, Russia:
K. Yu. Shunyaev, Senior Researcher of Laboratory of Electronic Microscopy

We studied the influence of macrocomponents in sulfide ore materials on determination of valuable microcomponents (gold, silver and cobalt) by atomic emission spectroscopy with inductively coupled plasma. The degrees of matrix influence of copper, iron, nickel, and sulfur on spectral lines for analytes were calculated. The influence of sulfur on the analytical signal of gold, silver and cobalt was carried out theoretically using the equilibrium thermodynamic modeling. Compensation of matrix interferences was achieved by adding copper, nickel and iron into the calibration solutions. The optimal operational parameters were established: maximum values of emission signal for analytes were observed at a generation power of 1500 W, argon flow rates of 0.70 dm³/min, and a position of observation zone of 15 mm for axial plasma observation. A technique was developed for determining 0.0001–0.001% of gold, 0.001–0.01% of silver, and 0.02–0.6% of cobalt in sulphide ores, concentrates and their processing products, containing up to 40% of sulfur, copper, nickel and iron. The detection limits for gold and cobalt (0.08 g/t), and silver (0.1 g/t) were calculated using the Au I 267.595 nm, Ag I 328.068 nm, and Co II 238.892 nm spectral lines. The efficiency of the technique was proved using eight certified reference materials of copper, nickel, gold-silver ores, concentrates, and mattes; the results of target component determination agree satisfactory with certified contents.

1. Zakharov Yu. A., Okunev R. V., Irisov D. S., Khaybullin R. R., Khasanova S. I. Atomic absorption determination of gold and silver in rocks and ores using double-stage probe atomization in the graphite furnace. Analitika i kontrol. 2013. Vol. 17, No. 4. pp. 414–422.
2. El Wakil A. F. Studies on the determination of gold in geological samples without separation by ICP-OES. Der farma Chemica. 2015. Vol. 7, No. 12. pp. 122–128.
3. GOST 32221–2013. Copper concentrates. Methods of analysis. State Standard. Introduced: 2015–01–01.
4. ISO 10378:2016. Copper, lead and zinc sulfide concentrates. Determination of gold and silver. Fire assay gravimetric and flame atomic absorption spectrometric method.
5. Branch register of analytical methods, recommended to use at laboratoryanalytical provision of exploration work on solid minerals. Vserossiyskiy nauchno-issledovatelskiy institut mineralnogo syrya imeni Fedorovskogo. Available at: http://vims-geo.ru/wp-content/uploads/2017/06/Reestr-MVI_v2_2017-2-kv..pdf
6. Kryazhov A., Panova S., Pakrieva E., Oskina Y. Determination of Au, Pb, Ni, Co in silicate rocks and ores by atomic absorption spectroscopy with graphite furnace. Advanced Materials Research. 2014. Vol. 1040. pp. 282–285.
7. Fouad H. K., Elrakaiby R. M., Hashim M. D. The Application of flame atomic absorption spectrometry for gold determination in some of its bearing rocks. American Journal of Analytical Chemistry. 2015. No. 6. pp. 411–421.
8. Vasileva I. E., Pozhidaev Yu. N., Vlasova N. N., Voronkov M. G., Filipchenko Yu. A. Sorption-atomic-emission determination of gold, platinum and palladium in rocks and ores using sorbent PSTM-3T. Analitika i kontrol. 2010. Vol. 14, No. 1. pp. 16–24.
9. Balaram V., Vummiti D., Roy P., Taylor C., Kar P., Raju A. K., Abburi K. Determination of precious metals in rocks and ores by microwave plasma-atomic emission spectrometry for geochemical prospecting studies. Current science. 2013. Vol. 104, No. 9. pp. 1207–1215.
10. Mayorova A. V., Pechishcheva N. V., Shunyaev K. Yu. Theoretical and experimental studies of the effectiveness of sample preparation methods of nonferrous metals sulfide raw materials for the determination of the micro- and macro-components by ICP-AES. Butlerovskie soobshcheniya. 2015. Vol. 44, No. 11. pp. 79–86.
11. Pupyshev A. A., Danilova D. A. Design of thermochemical processes model for atomic-emission spectrometry with inductively coupled plasma. Part 1. Matrix non-spectral interferemce. Analitika i kontrol. 2001. Vol. 5, No. 2. pp. 112–136.
12. Pupyshev A. A., Danilova D. A. Modeling of element emission signals during the spectrum excitation in inductively coupled plasma and its axial observance. Problemy spektroskopii i spektrometrii : mezhvuzovskiy sbornik nauchnykh trudov. Ekaterinburg : UGTU-UPI, 2004. No. 17. pp. 41–51.
13. Haraguchi H., Hasegawa T., Abdullah M. Inductively coupled plasmas in analytical atomic spectrometry: excitation mechanisms and analytical feasibilities. Pure and Applied Chemistry. 1988. Vol. 60, No. 5. pp. 685–696.
14. GOST 26628–85. Iron ores, concentrates, agglomerates and pellets. Methods of cobalt determination. State standard. Introduced: 1987–01–01.