Ramat Geri Kazanım Prosesinde Açığa Çıkan Cüruflardan Gravite Ayırması ile Altın Kazanımı

Öz

Bu araştırmada, ramatlardan altın/gümüş elde etmek için uygulanan ramat geri kazanım prosesinde açığa çıkan cürufta hapsolan altının gravite ayırması ile uygun koşullarda geri kazanımı amaçlanmış, maliyetleri azaltmak ve değerli metallerin geri kazanımını en üst düzeye çıkarmak için yüksek tenörlü/verimli altın ön konsantresi üretiminin mümkün olup olmadığı araştırılmıştır. Gravite ayırması ile zenginleştirme çalışmalarında santrifüj esaslı Knelson konsantratörü kullanılmıştır. Au tenörü 7 g/t olan soda-boraks esaslı cürufun bileşiminde yüksek oranda Fe2O3 (%13,25) ve PbO (%11,38) olduğu, boyuta göre yapılan sınıflandırma sonucu altının -0,5 + 0,212 mm fraksiyonunda yoğunlaştığı (%34) belirlenmiştir. Knelson konsantratörünün işletme parametreleri (yıkama suyu basıncı, santrifüj kuvvet, besleme hızı, pülp katı oranı vs.) ile besleme malı tane boyutunun konsantre/artığın Au tenörü ve altın kazanma verimine etkisi incelenmiştir. Altın kazanma verimi ve artığa kaçan altın miktarları dikkate alındığında yıkama suyu basıncı, santrifüj kuvvet ve besleme hızının ayırma performansına etkisinin sınırlı olduğu, besleme tane boyutunun ise konsantre Au tenörü üzerinde etkili olduğu tespit edilmiştir. 7 g/t Au tenörüne sahip cüruftan en uygun şartlarda %72,4 verimle 16 g/t Au içeren bir konsantre (artığın Au tenörü: 3 g/t) elde edilmiştir. Altının fraksiyonel bazda en yüksek dağılım gösterdiği -0,212 mm boyutunda besleme malı ile çalışıldığında, konsantrenin Au tenörü kayda değer bir artış göstererek 30 g/ton'a ulaşmıştır.

Anahtar Kelimeler

• Ramat
• cüruf
• gravite ayırması
• altın kazanımı

Recovery of Gold From Slags Generated in the Jewelry Waste Recycling Process by Gravity Separation

Öz

In this research, it is aimed to recover the gold from slags generated in the jewelry waste recycling process applied to obtain gold / silver from jewelry waste under suitable conditions by gravity separation and it has been explored whether it is possible to produce high grade / efficient gold pre-concentrate to reduce costs and maximize the recovery of precious metals. The Knelson centrifugal concentrator was used in enrichment studies by gravity separation. It has been determined that the composition of soda-borate based slag with a Au grade 7 g/t consists of relatively high Fe2O3 (13.25%) and PbO (11.38%), and the gold was concentrated in the fraction of -0.5 + 0.212 mm (34%) as a result of the size classification. The influence of operating conditions parameters of Knelson concentrator (washing water pressure, centrifugal force, feed rate, pulp solids ratio, etc.) and feed product particle size on Au grade and gold recovery efficiency of concentrate / waste were investigated. Considering the recovery rate of gold and the amount of gold in the tailings, it was determined that the effect of washing water pressure, centrifugal force and feed rate on the separation performance was limited, and the feed product particle size was effective on concentrate Au grade. A final concentrate containing 16 g/t of Au (Au grade of tailing: 3 g/t) was obtained with 72.4% recovery rate from the slag with 7 g/t Au grade at optimized conditions. In case of applying with the feed product sized of -0,212 mm, where the gold shows the highest distribution by size fraction, the Au grade of the concentrate increased significantly to 30 g/t.

Anahtar Kelimeler

• Jewelry waste
• slag
• gravity separation
• gold recovery

Kaynakça

1. Garside M., "Distribution of Global Gold Demand by Industry in 2017", Statista, https://www.statista.com/statistics/299609/gold-demand-by-industry-sector-share/ Yayın tarihi Ağustos 9, 2019. Erişim tarihi Nisan 17,( 2020).
2. DOĞAKA, "TR63 Bölgesi Kuyumculuk Sektör Raporu", Doğu Akdeniz Kalkınma Ajansı (DOĞAKA), (2015).
3. Delfini M., Manni A., Massacci P., "Gold recovery from jewellery waste", Minerals Engineering, 13(6): 663–666, (2000).
4. Embleton F.T., "Refining of Gold from Jewellery Scrap", Johnson Matthey Chemicals Ltd., England, (1989).
5. Corti C.W., "Recovery and refining of gold jewellery scraps and wastes", Proceedings of the Santa Fe Symposium on Jewelry Manufacturing Technology, Albuquerque-A.B.D., 1–20, (2002).
6. Potgieter J.H., Potgieter S.S., Mbaya R.K.K., Teodorovic, A., "Small-scale recovery of noble metals from jewellery wastes", Journal of the Southern African Institute of Mining and Metallurgy, 104(10): 563–572, (2004).
7. Burat F., Baştürkcü H., Özer M., "Gold&silver recovery from jewelry waste with combination of physical and physicochemical methods", Waste Management, 89: 10–20, (2019).
8. Burat F., Demirağ A., Şafak M.C., "Recovery of noble metals from floor sweeping jewelry waste by flotation‑cyanide leaching", Journal of Material Cycles and Waste Management, 22: 907– 915, (2020).

9. Michaud D., "Gold Smelting & Refining Process", 911Metallurgist, https://www.911metallurgist.com/blog/gold-smelting-refining-process. Yayın tarihi Şubat 28, 2016. Erişim tarihi Nisan 17, (2020).
10. Wills B.A., "Mineral Processing Technology", Eighth ed., Butterworth-Heinemann, Oxford, (2016).
11. Banisi S., Laplante A.R., Marois J., "The behaviour of gold in Hemlo Mines Ltd. grinding circuits", CIM Bulletin, 84 (955): 72–84, (1991).
12. Laplante A.R., Woodcock F., Noaparast M., "Predicting gravity separation gold recoveries", Minerals and Metallurgical Processing, 12 (2): 74–79, (1995).
13. Houseley K., Apling A.C., Chapman R.J., Watson R.P., "Use of homogeneous feed matrix for shape control during milling: Effect on gold gravity concentration", Transactions of the Institutions of Mining and Metallurgy: Section C, 106: 142–144, (1997).
14. Houseley K., Apling A.C., Chapman R.J., "Effect of particle size and shape on recovery of gold by use of a Knelson Concentrator", Innovation in Physical Separation Technologies, Richard Mozley Symposium, 65– 72, (1998).
15. Chen Q., Yang H., Tong L., Niu H., Zhang F., Chen G., "Research and application of a Knelson concentrator: A review", Minerals Engineering, 152: 1–15, (2020).
16. Ofori-Sarpong G, Amankwah R.K., "Comminution environment and gold particle morphology: Effects on gravity concentration", Minerals Engineering, 24: 590–592, (2011).
17. Koppalkar S., "Effect of operating variables in Knelson concentrators: A Pilot-scale study", PhD Thesis, McGill University, Montreal, (2009).
18. Spiller D.E., "Gravity Separation of Gold Then and Now", Mining Yearbook, Colorado Mining Association, Colorado, (1983).
19. Burt O.R., "Gravity Concentration Technology", Developments in Mineral Processing, Elsevier Science Publishers, Vol 5, (1984).
20. Grayson, R., "Fine gold recovery – Alternatives to mercury and cyanide", World Placer Journal, 7: 66–161, (2007).
21. Ghaffari A., Farzanegan A., "An investigation on laboratory Knelson concentrator separation performance: Part 1: Retained mass modelling", Minererals Engineering, 112: 57–67, (2017).
22. Ling J., "Variable speed knelson concentrator", PhD Thesis, McGill University, Montreal, (1998).
23. Chapman, R.J., Houseley, K., "The effect of particle geometry on the recovery of gold grains by gravity concentration methods", 28th Annual Conference of Canadian Mineral Processors, 335–357, (1996).