KARBON DİOKSİT İLE ATIK ÇÖZELTİLERDEN SİYANÜR GERİ KAZANIMI

Yıl 2017, , 171 - 177, 24.12.2017

Elif Yılmaz , Fırat Ahlatcı Ersin Y. Yazıcı , Oktay Celep Haci Deveci

https://doi.org/10.22531/muglajsci.346041

Cited By: 3

Öz

Siyanür liçi işlemleri sonucu üretilen atık
çözeltiler, siyanür içeriğinin yasal sınırlara indirilebilmesi için arıtma
işlemine tabi tutulmaktadır. Siyanür geri kazanımı ekonomik ve çevresel
nedenlerden dolayı, özellikle siyanür tüketimi yüksek cevherler için en çok
tercih edilen seçenektir. Bu çalışmada, alkali çözeltilerde hidrojen siyanürün
(HCN(g)) absorpsiyonu/geri kazanımı öncesinde siyanür çözeltilerinin
asitleştirilmesi amacıyla karbon dioksit (CO2) kullanılmıştır. Yapılan kinetik
testler, reaksiyon süresinin siyanür geri kazanımında önemli bir rol oynadığını
göstermiştir (90 dk.’da %89,1 siyanür geri kazanımı). Siyanür konsantrasyonu
(0,5-1,5 g/L NaCN), karbon dioksit akış debisi (0,38-1,15 L/dk. CO2) ve
süre’nin (30-90 dk.) siyanür geri kazanımı (%) üzerindeki etkisi iki seviyeli
tam faktöriyel deney tasarımı kullanılarak araştırılmıştır. Verilerin
istatistiksel analizi karbon dioksit akış hızı ve süre’nin istatistiksel olarak
anlamlı parametreler olduğunu göstermiştir. Siyanür konsantrasyonunun prosesin
etkinliği üzerinde bir etkisinin olmadığı belirlenmiştir. Elde edilen sonuçlar,
uygun koşullarda %93,1’e varan yüksek siyanür geri kazanımlarına
ulaşılabileceğini göstermiştir. Karbon dioksit kaynağı olarak hava (1,15 L/dk.)
kullanılmanın etkin olmadığı ve yüksek verimler için daha uzun süre gerektiği
bulunmuştur (15 dk.’da kazanım sıfır iken 24 saatte %95,4 olmuştur). Gerçek bir
yüklü liç çözeltisinden yapılan testte %49,7 verim elde edilmiştir. Elde edilen
bulgular karbon dioksitin siyanürlü atık çözeltilerin asitleştirilmesinde ve
siyanürün geri kazanımında kullanılabileceğini göstermiştir.

Anahtar Kelimeler

Siyanür geri kazanımı, Karbon dioksit, Asitleştirme, Deney tasarımı

RECOVERY OF CYANIDE FROM EFFLUENTS USING CARBON DIOXIDE

Öz

Cyanidation effluents are treated in order to reduce the cyanide level down to regularity limits. Cyanide recovery is the most desired route for treatment of effluents of high cyanide consuming ores, in particular, due to economic and environmental incentives. In this study, carbon dioxide (CO2) was utilised as an alternative for acidification of cyanide solutions prior to absorption/recovery of hydrogen cyanide (HCN(g)) in alkaline solutions. Kinetic tests have indicated that reaction time is an important parameter for the recovery of cyanide, which reached 89.1% over a period of 90 min. Effects of concentration of cyanide (0.5-1.5 g/L NaCN), flow rate of carbon dioxide (0.38-1.15 L/min. CO2) and time (30-90 min.) on the recovery of cyanide (%) were investigated in detail by a two-level full factorial design (23). The statistical evaluation of the data showed that flow rate of carbon dioxide and time were statistically significant parameters. Efficiency of the process was not affected by the concentration of cyanide. The results demonstrated that high recoveries of cyanide up to 93.1% could be achieved under suitable conditions. Introduction of air (1.15 L/min.) as a carbon dioxide source was found to be inefficient and require longer reaction periods for high recoveries i.e. no recovery at 90 min. vs. 95.4% at 24 h. A separate test performed using a real pregnant leaching solution (PLS) yielded a cyanide recovery of 49.7%. These finding demonstrated that using carbon dioxide can be used for acidification of cyanide solutions for cyanide recovery.

Anahtar Kelimeler

Cyanide recovery, Carbon dioxide, Acidification, Experimental design

Kaynakça

• [1] Adams, M. and Lloyd, V., “Cyanide recovery by tailings washing and pond stripping”, Minerals Engineering, 21, 501-508, 2008.
• [2] Adams, M.D., “Impact of recycling cyanide and its reaction products on upstream unit operations”, Minerals Engineering, 53, 241-255, 2013.
• [3] Akcil, A., “First application of cyanidation process in Turkish gold mining and its environmental impacts”, Minerals Engineering, 15, 695-699, 2002.
• [4] Bas, A.D., Yazici, E.Y. and Deveci, H., “Treatment of a copper- rich gold ore by ammonia assisted cyanide leaching”, XXVI. International Mineral Processing Congress (IMPC), New Delhi, pp. 356-365, 2012.
• [5] Benjamin, M., Water chemistry, McGraw-Hill, 668 pages, 2001.
• [6] Botz, M.M., Mudder, T.I. and Akcil, A.U. (Mike, D.A., Wills, B.A.), Developments in Mineral Processing, “Cyanide treatment: Physical, chemical and biological processes”, Elsevier, pp. 672-702, 2005.
• [7] Celep, O., Altın Cevherlerinin Zenginleştirilmesi, Türkiye Alim Kitapları, 220 pages, 2015.
• [8] Dai, X., Simons, A. and Breuer, P., “A review of copper cyanide recovery technologies for the cyanidation of copper containing gold ores”, Minerals Engineering, 25, 1-13. 2012.
• [9] Demopoulos, G.P. and Cheng, T.C., “A case study of CIP tails slurry treatment: comparison of cyanide recovery to cyanide destruction”, The European Journal of Mineral Processing and Environmental Protection (EJMP&EP), 4, 1-9, 2004.
• [10] Deschênes, G. and Prud'homme, P.J.H., “Cyanidation of a copper-gold ore”, International Journal of Mineral Processing, 50, 127-141, 1997.
• [11] Design-Expert, 2010, DOE Software, Stat-Ease Inc., Minneapolis, USA, 8.0.7.1, USA.
• [12] Dobrosz-Gómez, I., García, B.D.R., GilPavas, E. and García, M.Á.G., “Kinetic study on HCN volatilization in gold leaching tailing ponds”, Minerals Engineering, 110, 185-194, 2017.
• [13] Fleming, C.A., “The Economic and environmental case for recovering cyanide from gold plant tailings”, SGS Minerals Services, Technical Paper #2003-02, 2003.
• [14] Fleming, C.A., (Mike, D.A., Wills, B.A.), Developments in Mineral Processing, “Cyanide recovery”, Elsevier, pp. 703-727, 2005.
• [15] Fleming, C.A., “Cyanide management in the gold industry”, SGS Minerals Services, Technical Paper #2010-04, 2010.
• [16] Gönen, N., Kabasakal, O.S. and Özdil, G., “Recovery of cyanide in gold leach waste solution by volatilization and absorption”, Journal of Hazardous Materials, 113, 231-236, 2004.
• [17] Johnson, C.A., “The fate of cyanide in leach wastes at gold mines: An environmental perspective”. Applied Geochemistry, 57, 194-205, 2015.
• [18] Kuyucak, N. and Akcil, A., “Cyanide and removal options from effluents in gold mining and metallurgical processes”, Minerals Engineering, 50–51, 13-29, 2013.
• [19] Marsden, J. and House, I., “The chemistry of gold extraction”, Society for Mining, Metallurgy, and Exploration, USA, 688 pages, 2006.
• [20] Medusa, 2009, Software for chemical equilibrium diagrams, 32 bit version. Royal Institute of Technology, Sweden.
• [21] Mudder, T.I. and Botz, M.M., The chemistry and treatment of cyanidation wastes, Mining Journal Books Ltd, London, 393 pages, 2001.
• [22] Mudder, T.I. and Botz, M.M., “Cyanide and society: a critical review”, The European Journal of Mineral Processing and Environmental Protection (EJMP&EP), 4, 62-74, 2004.
• [23] Official Gazette, Regulation on Mining Wastes, Ministry of Environment and Urbanisation, Turkey, 15.07.2015, Issue: 29417, 2015.
• [24] Ritcey, G.M., “Tailings management in gold plants”, Hydrometallurgy, 78, 3-20, 2005.
• [25] Riveros, P.A., Molnar, A.R. and Baša, F., “Treatment of a high-cyanide waste solution for cyanide and metal recovery”, CIM Bulletin 89, 153-156, 1996.
• [26] SGS, “Cyanide Recovery”, T3 SGS 019, Technical Paper, SGS Minerals Services, 2009.
• [27] Vapur, H. and Bayat, O., “Prediction of cyanide recovery from silver leaching tailings with AVR using multivariable regression analysis”, Minerals Engineering, 20, 729-737, 2007.
• [28] Xie, F., Dreisinger, D. and Doyle, F., “A Review on recovery of copper and cyanide from waste cyanide solutions”, Mineral Processing and Extractive Metallurgy Review, 34, 387-411, 2013.
• [29] Yazıcı, E.Y., “Removal of cyanide from wastewaters using hydrogen peroxide, activated carbon adsorption and ultrasonic waves”, M.Sc. Thesis, Karadeniz Technical University, Trabzon, Turkey (in Turkish), 2005.
• [30] Yazıcı, E.Y., Deveci, H., Alp, I., Uslu, T. and Celep, O., “Factors affecting decomposition of cyanide by hydrogen peroxide”, XXIII. International Mineral Processing Congress (IMPC), Istanbul, Turkey, 3-8 September, pp. 2439-2444, 2006.
• [31] Yazıcı, E.Y., Deveci, H. and Alp, I., “Treatment of cyanide effluents by oxidation and adsorption in batch and column studies”, Journal of Hazardous Materials, 166, 1362-1366, 2009.