Application of Roasting Pretreatment for Gold Dissolution from the Invisible Gold Concentrate and Mineralogical Interpretation of their Digested Products

In order to dissolve Au, Ag, and other valuable metals from gold ore concentrate, raw gold concentrate was pre-treated by roasting and salt-roasting at $750^{\circ}C$. The roasted concentrate was treated with aqua regia digestion to dissolve the valuable metals and higher amount of Au, Ag, and valuable metals were extracted from the roasted concentrates than from the raw concentrate. Higher amount of these metals were also extracted from the salt-roasted concentrate than from the roasted concentrate. The results of the gold dissolution experiments showed that the gold dissolution was most efficient when particle size, roasting temperature, and the percentage of added salt in salt roasting were about $181{\sim}127{\mu}m$, $750^{\circ}C$, and was 20.0%, respectively. The XRD analysis suggests that quartz and pyrite were not destroyed even through roasting at $750^{\circ}C$ and decomposition with aqua regia. However, through salt roasting, pyrite was completely decomposed, whereas quartz could not be destroyed through salt-roasting at $750^{\circ}C$ and aqua regia digestion. Accordingly, it was expected that the gold contained in quartz can not be dissolved through salt-roasting and treatment with aqua regia.

비가시성 금정광의 효율적 용해를 위한 소성전처리 적용과 분해 잔유물에 대한 광물학적 해석

금정광에 함유된 금, 은 및 유용금속을 효과적으로 용해시키기 위해서 비가시성 금정광을 소성 및 소금소성처리하였다. 이들 소성처리 생성물에 대하여 왕수분해 결과 금, 은 및 유용금속 함량은 비가시성 정광에서보다 소성정광에서, 그리고 소성정광에서 보다 소금소성정광에서 더 많이 용해되었다. 금과 은이 최대로 용해되는 입도는 $181{\sim}127{\mu}m$, $750^{\circ}C$의 소성온도, 그리고 20%의 소금첨가량에서였다. XRD 분석을 수행한 결과, 석영과 황철석은 $750^{\circ}C$의 소성처리, 그리고 왕수분해에도 불구하고 분해되지 않았다. 황철석은 소금소성처리에 의하여 완전하게 분해되었지만 석영은 파괴되지 않았다. 따라서 석영에 함유된 금은 소금소성처리나 왕수분해를 수행해도 용해되지 않을 것으로 예상된다.