Effect of Na2S+NaOH pre-identification leaching on oxidized refractory Au-Ag ores

Öz

This study was conducted to investigate the effect of the alkaline sulfide (Na2S+NaOH) pre-identification process on cyanide leaching performance in oxidized refractory gold-silver ores. The ore has intensive oxide, carbonate, and silicate content, and contains Au/Ag minerals containing electrum, acanthite, and silver-bearing FePbZn Sulphate-Arsenate/Hydroxide minerals together with Fe, Pb, and Zn minerals. Niğde Ulukışla refractory Au/Ag ore has 8-9 g/T gold and 170-180 g/T silver grades. In mineralogical examinations, it was found that these metals were closed in minerals such as iron oxy/oxyhydroxide, calcite, and quartz or neighboring these minerals. In the cyanide soluble process after alkali sulfide preliminary procedure at room temperature, metal extraction yields were obtained as 62% for gold and 7% for silver. It is seen that silver is adversely affected by this process compared to the direct cyanidation process. However, after the hot alkali treatment process, metal extractions improved by approximately 25% of gold and 74% of silver. This increase in yield can be considered as converting Ag-oxyhydroxide into soluble Ag forms as a result of the effect of hot alkaline sulfur leaching on the cyanide process. The most important advantage of this decomposition process is to achieve high metal extraction efficiency in lower alkali concentrations.

Anahtar Kelimeler

• Na2S
• NaOH
• Gold
• Silver
• Refractory ore

Oksitlenmiş refrakter Au-Ag cevherleri üzerinde Na2S+NaOH ön tanımlama liçinin etkisi

Öz

Bu çalışma, oksitli refrakter altın-gümüş cevherlerinde alkali sülfür ön tanımlama işleminin siyanür liç performansına etkisini araştırmak amacıyla yapılmıştır. Yoğun oksit, karbonat ve silikat içeriğine sahip olan cevherde Fe, Pb ve Zn minerallerinin yanı sıra elektrum, akantit ve gümüş içeren FePbZn Sülfat-Arsenat/Hidroksit minerallerini içeren Au/Ag mineralleri de bulunmaktadır. Niğde Ulukışla refrakter Au/Ag cevheri 8-9g/t altın ve 170-180g/t gümüş tenörlerine sahiptir. Mineralojik incelemelerde, bu metallerin demir oksi/oksi hidroksit, kalsit, kuvars gibi minerallerin içerisinde kapanım halinde bulunduğu ya da bu minerallerle komşu olduğu tespit edilmiştir. Oda sıcaklığında gerçekleştirilen alkali sülfür ön işlemi sonrası siyanür çözündürme prosesinde metal kazanım verimleri altın için %62 ve gümüş için %7 olarak elde edilmiştir. Direkt siyanürleme işlemi ile kıyaslandığında gümüşün bu işlemden olumsuz etkilendiği görülmektedir. Bununla beraber, sıcak alkali işlem prosesinden sonra, metal ekstraksiyonlarında yaklaşık olarak %25 oranında altında ve %74 oranında gümüşte iyileşme meydana gelmiştir. Bu verim artışı sıcak alkali sülfür liçinin siyanür prosesine etkisi sonucu Ag-Oksihidroksitleri çözünebilir Ag formlarına dönüştürmesi şeklinde değerlendirilebilir. Bu bozundurma prosesinin en önemli avantajı ise daha düşük alkali konsantrasyonunda yüksek metal kazanım verimlerinin ulaşılabilmesidir.

Anahtar Kelimeler

• Na2S
• NaOH
• Altın
• Gümüş
• Refrakter cevher

Kaynakça

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