INVESTIGATION OF THE AMENABILITY OF A COPPER-RICH REFRACTORY GOLD ORE TO CYANIDE LEACHING

Year 2020, Volume: 59 Issue: 4, 225 - 234, 01.12.2020

Deus Albert Msumange Ersin Yener Yazıcı , Oktay Celep , Hacı Deveci

https://doi.org/10.30797/madencilik.843761

Cited By: 2

Abstract

The production of gold from refractory gold ores has been increasing due to the exhaustion of free
milling gold ores. The presence of cyanicides (e.g., copper minerals) and encapsulation of gold
in minerals such as pyrite and arsenopyrite are common reasons for refractoriness of gold ores.
In this study, the amenability of a copper-rich gold ore (108 g/t Au, 1.60% Cu) to cyanide leaching
was investigated. Direct cyanide leaching of the ore showed that the gold extraction was very low
by 18.4% over 24 h., indicating that the ore is highly refractory. Sulphuric acid pretreatment for
the removal of acid-soluble copper was found to be not effective to achieve high gold extractions
at the subsequent cyanide leaching. Leaching at high NaCN concentrations (1-8 g/L) yielded
limited Au extractions of ≤47.2%. Ultra-fine grinding (UFG) (d80: 8-73 μm) as a pretreatment route
followed by cyanide leaching also could provide Au recoveries of just below 54.1%. The findings
showed that the ore is double-refractory and needs the employment of more effective pretreatment
process(es) to achieve acceptable gold extractions (>90%) in subsequent cyanidation stage.

Keywords

Gold, Copper-gold ores, Cyanide leaching, Acid pretreatment, Ultra-fine grinding, Refractory gold ore

BAKIR İÇERİĞİ YÜKSEK REFRAKTER BİR ALTIN CEVHERİNİN SİYANÜR LİÇİNE UYGUNLUĞUNUN ARAŞTIRILMASI

Abstract

Serbest altın içeren cevherlerin giderek tükenmesi nedeniyle refrakter altın cevherlerinden altın
üretimi artmaktadır. Siyanür tüketen minerallerin (bakır mineralleri gibi) varlığı ve altının pirit ve
arsenopirit gibi mineraller içerisinde kapanım halinde bulunması altın cevherlerindeki refrakterliğin
yaygın nedenleri arasında yer almaktadır. Bu çalışmada, bakırca zengin bir altın cevherinin
(108 g/t Au, %1,60 Cu) siyanür liçine uygunluğu araştırılmıştır. Siyanür liçinde elde edilen düşük
(%18,4) altın kazanımı, cevherin yüksek derecede refrakter bir cevher olduğunu göstermektedir.
Sülfürik asit ön işlemi ile asitte çözünen bakırın uzaklaştırılması, takip eden siyanür liçinde
yüksek altın kazanımlarına ulaşılmasında etkili olmamıştır. Yüksek NaCN konsantrasyonlarında
(1-8 g/L) yapılan testlerde, sınırlı altın kazanımları (≤%47,2) elde edilmiştir. Siyanür liçinden önce
ön işlem olarak uygulanan çok ince öğütme (d80: 8-73 μm) sonrası altın kazanımları %54,1’in
altında kalmıştır. Elde edilen sonuçlar cevherin çift yönlü refrakter bir cevher olduğunu ve siyanür
liçi aşamasında kabul edilebilir (>%90) altın kazanımlarına ulaşmak için daha etkili ön işlem(ler)in
uygulanmasının gerekli olduğunu göstermiştir.

Keywords

Altın, Bakırlı altın cevherleri, Siyanür liçi, Asit ön işlemi, Çok ince öğütme, Refrakter altın cevheri

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