Sülfür Minerallerinde Bağlı Tane Davranımının Tahribatsız Elektrokimyasal Ölçümler Kullanılarak Yerinde Tayini

Öz

Sülfürlü cevher flotasyonu çoğunlukla, mineral yüzeyinde oluşan elektrokimyasal tepkimelere bağlıdır. Çeşitli flotasyon kimyasallarının flotasyon verimine etkisini anlamak açısından, palp içerisindeki karşılıklı tepki mekanizmalarını açıklayabilmek önemlidir. Sülfürlü minerallerin yarı iletken özelliklerinden yararlanılarak kullanılan elektrokimyasal yöntemler ile flotasyon uygulamalarında bu mekanizmalar ortaya konabilmektedir. Yapılan bu çalışmada, üç farklı tahribatsız elektrokimyasal yöntem – Açık Devre Potansiyeli (OCP), Dönüşümlü Voltametri (CV) ve Elektriksel Empedans Spektroskopisi (EIS) – kullanılarak bağlı ve serbest tanelerin elektrokimyasal tepkiselliğini ortaya koymak hedeflenmiştir. Deneysel çalışmalarda kullanılmak üzere çeşitli mineral elektrotları – Galen/Pirit (0,52 cm2), Galen/Sfalerit (0,35 cm2), saf Galen (0,20 cm2), saf Sfalerit (0,80 cm2) ve saf Pirit (0,18 cm2) – hazırlanmıştır. Üç elektrotlu elektrokimyasal hücre düzeneği kurularak, hazırlanan mineral elektrotlarıyla deneysel çalışmalar yapılmıştır. Mineral elektrotların yüzey kimyasındaki değişimler toplayıcılı (1×10-4 M NaEX) ve toplayıcısız ortamda denenerek kıyaslanmıştır. Bağlı tane mineral elektrotundaki ölçümler sırasında ortaya çıkan galvanik etkileşim sebebiyle, minerallerin yüzey alanından bağımsız olarak yük geçişlerinin olduğu tespit edilmiştir. Minerallerin birbirlerini indirgeyip yükseltgemeleri, flotasyon davranımlarının da değişmesine sebep olmuştur. Mevcut çalışmada kullanılan yöntemler, ortamdaki herhangi bir flotasyon reaktifinin sülfürlü mineral yüzeyinde meydana gelebilecek olası tepkimelere neden olan etkisini kolayca ölçebilmektedir. Bu sebeple elektrokimyasal ölçümlerin, kesikli laboratuvar flotasyon testlerine alternatif bir yöntem olabileceği düşünülmektedir.

Anahtar Kelimeler

• Sülfürlü Mineraller
• Yüzey Kimyası
• NaEX
• Dönüşümlü Voltametri
• Elektriksel Empedans Spektroskopisi

In Situ Characterization of the Locked Particle Behavior of Sulfide Minerals Using Non-Destructive Electrochemical Measurements

Öz

The flotation of sulfide minerals mostly depends on electrochemical reactions occurring on the mineral surfaces. Understanding the interaction mechanisms in the pulp is crucial for explaining the effects of different flotation chemicals on flotation performance. For this purpose, electrochemical techniques are used in the flotation of sulfide minerals by utilizing the semiconductor properties of these minerals. In this study, three non-destructive electrochemical measurements - open circuit potential (OCP), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) - were used to assess the electrochemical reactivity of the locked and liberated sulfide particles. Various combinations of mineral electrodes - Galena/Pyrite (0.52 cm2), Galena/Sphalerite (0.35 cm2), pure Galena (0.20 cm2), pure Sphalerite (0.80 cm2) and pure Pyrite (0.18 cm2) - were tested. A three-electrode electrochemical cell configuration was set up to investigate the electrochemical responses of the prepared electrodes. The changes in the surface chemistry of the mineral electrodes, in the presence (1×10-4 M NaEX) and absence of a collector were compared in detail. During the process, charge transitions occurred between the minerals in the locked particle mineral electrode due to galvanic interactions regardless of the surface area. Thus, the flotation behavior of the minerals changed by reducing and oxidizing each other. The present study suggests that the electrochemical methods may be an alternative technique to the conventional batch scale flotation tests as they can easily monitor the effect of any flotation reagents in the system causing possible reactions that may occur on sulfide mineral surfaces.

Anahtar Kelimeler

• Sulfide Minerals
• Surface Chemistry
• NaEX
• Cyclic Voltammetry
• Electrochemical Impedance Spectroscopy

Kaynakça

1. [1] Ekmekçi, Z. 2008. Electrochemistry in sulphide mineral research, Surface Chemistry and Flotation lecture notes, vol. Chapter 2. Ankara, pp. 8–26, 2008.
2. [2] Peters, E. 1977. The Electrochemistry of Sulphide Minerals, Trends in Electrochemistry, Boston, MA: Springer US, pp. 267–290. doi: 10.1007/978-1-4613-4136-9_16.
3. [3] Tercero, N., Nagaraj, D. R., and Farinato, R. 2019. A Critical Overview of Dithiophosphinate and Dithiophosphate Interactions with Base Metal Sulfides and Precious Metals, Mining, Metall. Explor., vol. 36, no. 1, pp. 99–110, Feb. 2019, doi: 10.1007/s42461-018-0039-1.
4. [4] Ertekin, Z., Pekmez, K., Kappes, R., and Ekmekçi, Z. 2021. Application of EIS technique to investigate the adsorption of different types of depressants on pyrite, Physicochem. Probl. Miner. Process., vol. 57, no. 3, pp. 112–126, 2021, doi: 10.37190/PPMP/136022.
5. [5] Liu, Q., Chen, M., Zheng, K., Yang, Y., Feng, X., and Li, H. 2018. In situ electrochemical investigation of pyrite assisted leaching of chalcopyrite, J. Electrochem. Soc., vol. 165, no. 13, pp. H813–H819, 2018, doi: 10.1149/2.0461813jes.
6. [6] Zhao, S., Guo, B., Peng, Y., and Mai, Y. 2017. An impedance spectroscopy study on the mitigation of clay slime coatings on chalcocite by electrolytes, Miner. Eng., vol. 101, pp. 40–46, Feb. 2017, doi: 10.1016/j.mineng.2016.09.027.
7. [7] Vianna, S. M., Franzidis, J., Manlapig, E. V, Silvester, E., and Ping-hao, F. 2003. The influence of particle size and collector coverage on the floatability of galena particles in a natural ore, in XXII International Mineral Processing Congress, 2003, no. October, pp. 816–826.
8. [8] Liu, Q., Li, H., and Zhou, L. 2009. Experimental study of pyrite-galena mixed potential in a flowing system and its applied implications, Hydrometallurgy, vol. 96, no. 1–2, pp. 132–139, 2009, doi: 10.1016/j.hydromet.2008.09.002.

9. [9] Gök, Ö., Güler, E., and Seyrankaya, A. 2012. Kalkopiritin asitli çözeltilerdeki elektrokimyasal davranışı, MT Bilim., vol. 1, no. 2, pp. 35–47, 2012.
10. [10] Urbano, G., Meléndez, A. M., Reyes, V. E., Veloz, M. A., and González, I. 2007. Galvanic interactions between galena-sphalerite and their reactivity, Int. J. Miner. Process., vol. 82, no. 3, pp. 148–155, 2007, doi: 10.1016/j.minpro.2006.09.004.
11. [11] Rao, S. R. and Finch, J. A. 1988. Galvanic interaction studies on sulphide minerals, Can. Metall. Q., vol. 27, no. 4, pp. 253–259, Oct. 1988, doi: 10.1179/cmq.1988.27.4.253.
12. [12] Mielczarski, E. and Mielczarski, J. A. 2003. Influence of galvanic effect on adsorption of Xanthate on pyrite , galena and chalcopyrite, in XXII International Mineral Processing Congress, 2003, no. October, pp. 866–873.
13. [13] Moslemi, H., Shamsi, P., and Alimohammady, M. 2012. Electrochemical properties of pyrite, pyrrhotite, and steel: Effects on grinding and flotation processes, J. South. African Inst. Min. Metall., vol. 112, no. 10, pp. 883–890, 2012.
14. [14] Izerdem, D. 2022. Surface chemistry of the locked particles for sulphide minerals, in 27th International Mining Congress and Exhibition of Turkey, 2022, pp. 855–863.
15. [15] Chander, S. 1988. Electrochemistry of sulfide mineral flotation, Mining, Metall. Explor., vol. 5, no. 3, pp. 104–114, Aug. 1988, doi: 10.1007/BF03402498.
16. [16] Güler, T. 2018. Redox behavior of galena in alkaline condition, Ionics (Kiel)., vol. 24, no. 1, pp. 221–227, 2018, doi: 10.1007/s11581-017-2172-0.
17. [17] Ertekin, Z., Pekmez, K., and Ekmekçi, Z. 2016. Evaluation of collector adsorption by electrochemical impedance spectroscopy, Int. J. Miner. Process., vol. 154, pp. 16–23, 2016, doi: 10.1016/j.minpro.2016.06.012.
18. [18] Güler, T., Şahbudak, K., Çetinkaya, S., and Akdemir, Ü. 2013. Electrochemical study of pyrite-ovalbumin interaction in relation to flotation, Trans. Nonferrous Met. Soc. China (English Ed., vol. 23, no. 9, pp. 2766–2775, 2013, doi: 10.1016/S1003-6326(13)62795-8.
19. [19] Qin, W., Wang, X., Ma, L., Jiao, F., Liu, R., and Gao, K. 2015. Effects of galvanic interaction between galena and pyrite on their flotation in the presence of butyl xanthate, Trans. Nonferrous Met. Soc. China, vol. 25, no. 9, pp. 3111–3118, Sep. 2015, doi: 10.1016/S1003-6326(15)63940-1.
20. [20] Wang, X.-H. 1995. Interfacial Electrochemistry of Pyrite Oxidation and Flotation, J. Colloid Interface Sci., vol. 171, no. 2, pp. 413–428, May 1995, doi: 10.1006/jcis.1995.1198.
21. [21] Hu, Y., Wu, M. ,Liu, R., and Sun, W. 2020. A review on the electrochemistry of galena flotation, Miner. Eng., vol. 150, p. 106272, May 2020, doi: 10.1016/j.mineng.2020.106272.
22. [22] Morey, M. S., Grano, S. R., Ralston, J., Prestidge, C. A., and Verity, B. 2001. The electrochemistry of PbII activated sphalerite in relation to flotation, Miner. Eng., vol. 14, no. 9, pp. 1009–1017, Sep. 2001, doi: 10.1016/S0892-6875(01)00108-X.
23. [23] Ekmekci, Z., Becker, M., Tekes, E. B., and Bradshaw, D. 2010. An impedance study of the adsorption of CuSO4 and SIBX on pyrrhotite samples of different provenances, Miner. Eng., vol. 23, no. 11–13, pp. 903–907, 2010, doi: 10.1016/j.mineng.2010.02.007.
24. [24] Mu, Y., Li, L., and Peng, Y. 2017. Surface properties of fractured and polished pyrite in relation to flotation, Miner. Eng., vol. 101, pp. 10–19, 2017, doi: 10.1016/j.mineng.2016.11.012.