Siyanürlü çözeltiden cıvanın uzaklaştırılması

Öz

Altın/Gümüş minerallerini içeren cevher yataklarında çoğunlukla belirli bir miktarda ağır metal ve toksisitesi yüksek olan cıva bulunmaktadır. Altının siyanür ile muamelesi esnasında altın ve gümüşle birlikte cıva da liç edilmektedir. Cıva-siyanür kompleksleri çok kararlı olduklarından liç çözeltisinde ve liç işlemini takip eden proseslerde kirliliğe sebep olmakla birlikte çevre ve sağlık açısından tehlike arz etmektedir. Bu nedenle cıvanın; hızlı, verimli, düşük maliyetli, seçimli, kararlı ve tehlikeli olmayan ayırma yöntemleri ile uzaklaştırılması ekonomik ve çevresel açıdan oldukça önemlidir. Bu çalışmada; altın, gümüş ve cıva içeren siyanürlü liç çözeltilerinden sodyum sülfür (Na₂S), sodyum dietilditiyokarbamat (Na-DDC) ve amonyum pirolidin ditiyokarbamat (APDC) kullanımıyla çöktürme ile cıva uzaklaştırma araştırılmıştır. Ayrıca koagulant (FeCl₃) ve flokulant (Superfloc A130) ilavesinin cıva uzaklaştırma verimine etkisi incelenmiştir. Çöktürme ile uzaklaştırmada APDC kullanımıyla %98,9 verimle Hg konsantrasyonu 8.0 mg L⁻1’ den 0.087 mg L⁻1’ ye düşürülmüştür.

Anahtar Kelimeler

• Altın cevherleri,siyanürleme,cıva,uzaklaştırma

Removal of mercury from cyanide solutions

Abstract

The gold/silver ores contain certain amount of mercury, which is a heavy metal and has high toxicity. During the treatment of gold with cyanide, mercury is also leached with gold and silver. Since mercury cyanide complexes are very stable, they cause contamination in leaching solution and are dangerous for the environment and health. For this reason, removal of mercury by fast, energy efficient, low cost, selective, stable and non-hazardous separation methods is very important in economic and environmental terms. In this study; removal of mercury from cyanide leach solutions were investigated using sodium sulfide (Na₂S), sodium diethyl dithio-carbamate (Na-DDC) and ammonium pyrrolidine dithio-carbamate (APDC) as precipitant by precipitation. In addition, the effect of coagulant (FeCl₃) and flocculant (Superfloc A130) addition on mercury removal efficiency was investigated. With the use of APDC, Hg concentration was decreased from 8.0 mg L⁻1 to 0.087 mg L⁻1 in a yield of 98.9%.

Keywords

• Gold ores,Cyanidation,Mercury,Removal

Kaynakça

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