Dilara TOKKAN, Bünyamin DÖNMEZ, Osman Nuri ATA

Cl2 gazı ile doyurulmuş HCI çözeltilerinde altın hurdalarından altının liçing kinetiği

Altın içeren hurdalardan altının liçingi üzerine kinetiği ortaya koyan modeli açıklamak için, reaksiyon sıcaklığı, asit konsantrasyonu, katı-sıvı oranı, karıştırma hızı ve partikül boyutunun etkileri araştırılmıştır. Cl2 ile doyurulmuş HCI çözeltilerindeki altın liç kinetiğinin incelenmesinde, ortamda meydana gelen Cl atomları, altın hurdaları ile Cl2 moleküllerine göre daha hızlı reaksiyon vermektedir. Bu reaksiyon, çözünme reaksiyonu ile eşzamanlı olarak gerçekleşir ve yerinde oluşturulan klor olarak isim alır. Yöntemin, üretilen klorun depolanması gibi bazı dezavantajları da yoktur. Liçing hızının, artan reaksiyon sıcaklığı, karıştırma hızı ve asit konsantrasyonunu ile artarken; katı-sıvı oranı ve partikül boyutunun artmasıyla azaldığı belirlenmiştir. Katı-sıvı sistemleri için büzülen nüve modellerini kullanan deneysel veriler analiz edilerek, altın içeren hurdalardaki altının liçinginin kimyasal kontrollü olduğu gözlenmiştir. Keza; çözünmenin kimyasal reaksiyon ile kontrol edilen liçing hızı, hız sabiti ve partikül boyutu arasındaki ilişki ile de desteklenmiştir. Liçing prosesinin aktivasyon enerjisi Statistica Paket Programı kullanılarak 34.40 kJ/mol olarak tespit edilmiştir.

Anahtar Kelimeler:

Altın içeren hurdalar, Klor gazı, Liçing kinetiği

The leaching kinetics of gold from gold scraps in Cl2-saturated HCl solutions

In order to explain the model of kinetics control on the leaching of gold in gold-bearing scraps, the effects of the reaction temperature, solid/ liquid ratio, particle size and stirring speed and acid concentration are investigated. In the examination of the leaching kinetics of gold in Cl2-saturated HCI solutions, Cl atoms occurring in the medium react more rapidly than Cl2 molecules with gold scraps. This reaction takes place simultaneously with the reaction of dissolution and in situ-generated chlorine is called. Also, the method doesn’t have some disadvantages such as the storage of generated chlorine. It is determined that the leaching rate decreases with increasing particle size and solid to liquid ratio while it increases with increasing reaction temperature, acid concentration and stirring speed. For fluid/solid systems, shrinking core models are analysed by using of experimental results. It is observed that the leaching of gold from gold-bearing scraps is chemically controlled. Also, the leaching rate controlled by the chemical reaction is supported by the relationship between the particle diameter and rate constant. The activation energy of leaching process by using Statistica Package Program is determined as 34.40 kJ/mol.

Keywords:

Gold-bearing scraps, Chlorine, Leaching kinetics,

PDF

___

Michelis I De, Olivieri A, Ubaldini S, Ferella F, Beolchini F, Vegliò F. “Roasting and chlorine leaching of gold-bearing refractory concentrate: experimental and process analysis”. International Journal of Mining Science and Technology, 23, 709-715, 2013.
Syed S. “Recovery of gold from secondary sources-A review”. Hydrometallurgy, 115-116, 30-51, 2012
Kulandaisamy SJ. Prabhakar J, Rethinaraj P, Adaikkalam P, Srinivasan GN, Raghavan M. “The Aqueous Recovery of Gold from Electronic Scrap”. Journal of the Minerals, Metals and Materials Society, 55(8), 35-38, 2003.
Nam KS, Jung BH, An JW, Ha TJ, Tran T, Kim MJ. “Use of chloride-hypochlorite leachants to recover gold from tailing”. International Journal of Mineral Processing, 86, 131-40, 2008.
Marsden JO, House CI. The Chemistry of Gold Extraction. 2nd ed. Colorada, USA, SME, 2006.
Norgate T, Jahanshahi S. “Low grade ores-smelt, leach or concentrate?”. Minerals Engineering, 23(2), 65-73, 2010.
Rüşen A, Topçu MA. “Optimization of gold recovery from copper anode slime by acidic ionic liquid”. Korean Journal of Chemical Engineering, 26(4), 607-610, 2017a.
Xu B, Yang Y B, Jiang T, Li Q, Zhang X, Wang D. “Improved thiosulfate leaching of a refractory gold concentrate calcine with additives”. Hydrometallurgy, 152, 214-222, 2015.
Dönmez B, Sevim F, Çolak S. “A study on recovery of gold decopperized anode slime”. Chemical Engineering & Technology, 24(1), 91-95, 2001.
Xing W, Lee M S. “Leaching of gold and silver from anode slime with a mixture of hydrochloric acid and oxidizing agents”. Geosystem Engineering, 20(4), 1-8, 2017.
Muir DM. “A review of the selective leaching of gold from oxidised copper-gold ores with ammonia-cyanide and new insights for plant control and operation”. Minerals Engineering, 24, 576-582, 2011.
Li J, Miller JD. “Reaction kinetics of gold dissolution in acid thiourea solution using ferric sulfate as oxidant”. Hydrometallurgy, 89(3-4), 279-288, 2007.
Grosse AC, Dicinoski, GW, Shaw MJ Haddad PR. “Leaching and recovery of gold using ammoniacal thiosulfate leach liquors (a review)”. Hydrometallurgy, 69(1-3), 1-2, 2003.
Nesbitt CC, Milosavlyevic E B, Hendrix JL. “Determination of the mechanism of the chlorination of gold in aqueous solutions”. Industrial and Engineering Chemistry Research, 29, 1696-700, 1990.
Rüşen A, Topçu MA. “Investigation of an alternative chemical agent to recover valuable metals from anode slime”. Chemical Papers, 72, 2789-2891, 2018.
Baghalha M. “Leaching of an oxide gold ore with chloride/hypochlorite solutions”. International Journal of Mineral Processing, 82, 178-186. 2007.
Kozin LF, Prokopenko V, Bogdanova AK. “Kinetics and mechanism of the gold corrosion dissolution in hypochlorite solutions”. Protection of Metals, 41(1), 22-29, 2005.
Vinals J, Juan E, Ruiz M, Ferrando E, Cruells M, Roca A, Casado J. “Leaching of gold and palladium with aqueous ozone in dilute chloride media”. Hydrometallurgy, 81, 142-151, 2006.
Baghalha M. “The leaching kinetics of an oxide gold ore with iodide/iodine solutions”. Hydrometallurgy, 42(50), 113-114, 2012.
Jeffrey MI, Breuer PL, Choo WL. “A kinetic study that compares the leaching of gold in the cyanide, thiosulfate, and chloride systems”. Metallurgical and Materials Transactions B, 32B, 979-986, 2001b.
Li Q, Zhang Y, Liu X, Xu B, Yang Y, Jiang T. “Improvement of gold leaching from a refractory gold concentrate calcine by separate pretreatment of coarse and fine size fractions”. Minerals, 7(5), 80, 2017.
Nikoloski A, Stockton B. “Application of alternative lixiviants for secondary heap leaching of gold”. 7th Mill Operators Conference, Kalgoorlie, Western Australia, 12-14 October 2000.
Levenspiel O. Chemical Reaction Engineering. 2nd ed. New York, USA, Wiley, 1994.