Siyanürlü çözeltiden cıvanın uzaklaştırılması

Yıl 2019, Sayı: 4, 30.06.2019

Sadiye Kantarcı , İbrahim Alp

Öz

Altın/Gümüş
minerallerini içeren cevher yataklarında çoğunlukla belirli bir miktarda ağır
metal ve toksisitesi yüksek olan cıva bulunmaktadır. Altının siyanür ile
muamelesi esnasında altın ve gümüşle birlikte cıva da liç edilmektedir.
Cıva-siyanür kompleksleri çok kararlı olduklarından liç çözeltisinde ve liç
işlemini takip eden proseslerde kirliliğe sebep olmakla birlikte çevre ve
sağlık açısından tehlike arz etmektedir. Bu nedenle cıvanın; hızlı, verimli,
düşük maliyetli, seçimli, kararlı ve tehlikeli olmayan ayırma yöntemleri ile
uzaklaştırılması ekonomik ve çevresel açıdan oldukça önemlidir. Bu çalışmada;
altın, gümüş ve cıva içeren siyanürlü liç çözeltilerinden sodyum sülfür (Na₂S),
sodyum dietilditiyokarbamat (Na-DDC) ve amonyum pirolidin ditiyokarbamat (APDC)
kullanımıyla çöktürme ile cıva uzaklaştırma araştırılmıştır. Ayrıca koagulant
(FeCl₃) ve flokulant (Superfloc A130) ilavesinin cıva uzaklaştırma
verimine etkisi incelenmiştir. Çöktürme ile uzaklaştırmada APDC kullanımıyla
%98,9 verimle Hg konsantrasyonu 8.0 mg L⁻1’ den 0.087 mg L⁻1’ ye düşürülmüştür.

Anahtar Kelimeler

Altın cevherleri, siyanürleme, cıva, uzaklaştırma

Removal of mercury from cyanide solutions

Öz

The
gold/silver ores contain certain amount of mercury, which is a heavy metal and
has high toxicity. During the treatment of gold with cyanide, mercury is also
leached with gold and silver. Since mercury cyanide complexes are very stable,
they cause contamination in leaching solution and are dangerous for the
environment and health. For this reason, removal of mercury by fast, energy
efficient, low cost, selective, stable and non-hazardous separation methods is
very important in economic and environmental terms. In this study; removal of
mercury from cyanide leach solutions were investigated using sodium sulfide (Na₂S),
sodium diethyl dithio-carbamate (Na-DDC) and ammonium pyrrolidine
dithio-carbamate (APDC) as precipitant by precipitation. In addition, the
effect of coagulant (FeCl₃) and flocculant (Superfloc A130) addition
on mercury removal efficiency was investigated. With the use of APDC, Hg
concentration was decreased from 8.0 mg L⁻1 to 0.087 mg L⁻1 in a yield of
98.9%.

Anahtar Kelimeler

Gold ores, Cyanidation, Mercury, Removal

Kaynakça

• References1. Hageman, S., Oppermann, U., Brasser, T. Behaviour of mercury and mercury compounds at the underground disposal in salt formations and their potential mobilization by saline solutions, Federal Environment Agency, Germany, 2014.2. Rice, K., M., Jr, E.M.W., Wu, M., Gillette, C., Blough, E., Environmental Mercury and Its Toxic Effects, Journal of Preventive Medicine & Public Health, 2014, 47, 74-83.3. Antoszczyszyn, T. and Michalska, A., The potential risk of environmental contamination by mercury contained in Polish coal mining waste, 2016, 15, 191-196.4. Pollution Types (in Turkish), https://acikders.ankara.edu.tr/pluginfile.php/15353/mod_ resource/content/0/2.%20hafta.pdf (accessed June 1, 2019).5. Gabby, K. Selective Mercury Sequestration from a Silver/Mercury Cyanide Solution. Ph.D. Thesis, Michigan Technological University, Chemical Engineering, Houghton, Michigan, 2013.6. Miller, J.D., Alfaro, E., Misra, M., and Lorengo, J., Mercury control in the cyanidation of gold ores, Proceedings of the Engineering Foundation: Technical Solutions for the Pollution Prevention in the Mining and Minerals Processing Industry, 1995, 151-164.7. Sandberg, R.G., Simpson, W.W., Staker, W.L., Calcium Sulfide Precipitation of Mercury During Cyanide Leaching of Gold Ores, Bureau of Mines Repost of Investigations, United Ststes Department of The ınterior, 1984, pp:13.8. Coles, C.A., and Cochrane, K., Mercury Cyanide Contamination Of Groundwater From Gold Mining And Prospects For Removal, Sea to Sky Geotechnique, 2016, 1118-1122.9. Boyle, D. R. and Smith, C. N. Mobilization of Mercury from a Gossan Tailings Pile, Murray Brook Precious Metal Vat leaching Operation, International Land Reclamation and Mine Drainage Conference and the Third International Conference on the Abatement of Acidic Drainage, Pittsburgh, PA, 1994, New Brunswick, Canada, April 24-29.10. Tassel, F., Rubio, J., Misra, M., Jena, B.C., Removal Of Mercury From Gold Cyanide Solution By Dissolved Air Flotation, Minerals Engineering, 1997, 10, 8, 803-811.11. Tessele, F., Misra, M., Rubio, J., Removal Of Hg, As And Se Ions From Gold Cyanide Leach Solutions By Dissolved Air Flotation, Minerals Engineering, 1998, 11, 6, 535—543.12. Matlock, M.M., Howerton, B.S., Aelstyn, M.A.V., Nordstrom, F.L., Atwood, D.A., Advanced Mercury Removal from Gold Leachate Solutions Prior to Gold and Silver Extraction: A Field Study from an Active Gold Mine in Peru, Environ. Sci. Technol., 2002, 36, 1636-1639.13. Vazquez, V., Parga, Jose, Valenzuela, L.J., Figueroa, G., Valenzuela, A., Munive, G., Recovery of Silver from Cyanide Solutions Using Electrochemical Process Like Alternative for Merrill-Crowe Process, Materials Sciences and Applications, 2014, 5, 863-870.14. Misra, M, Lorengo, J., Nabor, J.B., Bucknam, C.B., Removal of mercury cyanide species from solutions using dimethyl dithiocarbamates, Mining, Metallurgy & Exploration, 1998, 15, 4, 60-64.15. Washburn, C. and Hill, E., Mercury retorts for the processing of precious metals and hazardous wastes, Precious Metals: Pyrometallurgy, 2003, 45-50.16. Simpson, W.W., Staker, W.L., Sandberg, R.G., Calcium Sulfide Precipitation of Mercury From Gold - Silver Cyanide-Leach Slurries, Bureau of Mines Repost of Investigations, United Ststes Department of The ınterior, 1986, pp:8.17. Atwood, D.A., Mercury removal in the gold-cyanide process, Minerals & Metallurgical Processing, 2003, 20, 4, 211-212.18. Stevens, J.G., Selective Removal of Mercury from Gold Bearing Streams, Johnson Matthey Technol. Rev., 2015, 59, 4, 322–330.19. Yang, M., Wang, S., Zhang, L., Wu, Q., Wang, F., Hui, M., Yang, H., Hao, J., Mercury emission and speciation from industrial gold production using roasting process, Journal of Geochemical Exploration, 2016, 170, 72–77.20. McLeod, K.N., Alkaline Sulfide Leach of Cinnabar Ore and Electrolytic Deposition of Mercury From the Leach Solution. Ph.D. Thesis, Oregon State College, June 1939.21. Flynn, C.M., Reno, Jr., Carnahan, T.G., Lindstrom, R.E., Selective Removal Of Mercury From Cyandesolutions. United States Patent 4,256,707 , Mart, 17, 1981.22. Gabby, K.L. and Eisele, T.C., Selective removal of mercury using zinc sulfide, Minerals & Metallurgical Processing, 2013, 30, 2, 91-94.23. Özdil, H.,E., Usage Of Schiff Bases For Preconcentration Of Mercury And Determination Of Mercury By Aas Cold Vapor Techniques, Master Thesis, Ankara University, Graduate School of Natural and Applied Science, Department of Chemistry, Ankara, 2012.24. AA Mercury cold vapor and Hydride generation, Atomic absorbtion: Mecury and Asenic, http://delloyd.50megs.com/moreinfo/hydride.html (accessed June 1, 2019).25. Houserova, P., Matejicek, D., Kuban, V., High-performance liquid chromatographic/ion-trap mass spectrometric speciation of aquatic mercury as its pyrrolidinedithiocarbamate complexes, Analytica Chimica Acta, 2007, 596, 242–250.