본 연구 목적은 페널티원소가 포함된 정광을 질산용액으로 마이크로웨이브 용출하여 Bi와 As를 효과적으로 용출하고자 하였다. 정광시료에 대한 페널티원소와 유용금속들의 용출특성을 마이크로웨이브 용출시간, 질산농도 및 정광 첨가량에 대하여 조사하였다. 그 결과 페널티원소인 Bi와 As의 용출률은 마이크로웨이브 용출시간이 증가할수록, 질산농도가 증가할수록 그리고 정광 첨가량이 감소할수록 증가하였다. 정광과 광석광물을 마이크로웨이브 가열하자, Bi가 90% 이상 제거되었고, 황비철석은 자류철석-적철석으로 상변환 되었다. 고체-잔류물에 대하여 XRD분석한 결과, 단체 황과 anglesite가 나타났다. 단체 황과 anglesite의 XRD peak는 1분에서보다 12분에서, 0.5 M보다 4 M에서 그리고 5 g보다 30 g에서 intensity가 더 증가하였고 예리해졌다. 이와 같은 결과는 용출효율이 증가할수록 더 많은 단체 황과 anglesite가 생성되기 때문인 것으로 사료된다. 정광을 마이크로웨이브 가열하면 Bi와 As가 대기 중으로 손실되지만, 질산용액으로 마이크로웨이브 용출하면 Bi와 같은 유용금속이 용출되어 회수될 수 있음을 확인하였다.

The aim of this study was to leach penalty elements, such as Bi and As, effectively through microwave leaching of a gold concentrate sample containing penalty elements with nitric acid solution. For this purpose, the time effect of microwave leaching, nitric acid concentration effect, and sample addition effect in a microwave were examined. The experiment, demonstrated that the leaching rate of penalty elements increased as microwave leaching time and nitric acid concentration increased and concentration addition decreased. When a microwave heating experiment was carried out on the concentrate and ore minerals, Bi was removed by as much as 90%, and the phase of arsenopyrite was transformed in the order of arsenopyrite (FeAsS), pyrrhotite (FeS), and hematite (Fe₂O₃). When the X-ray diffraction (XRD) analysis was carried out with solid residue, elemental sulfur and anglesite were identified. The intensity of the XRD peaks of elemental sulfur and anglesite increased, and the peaks were sharper when the microwave leaching time was 12 min instead of 1 min, the nitric acid concentration was 4 M in rather than 0.5 M, and the concentration addition was 30 g rather than 5 g. This was probably because more elemental sulfur and anglesite were generated in the leaching solution as the leaching efficiency increased. Bi can be leached as valuable elements in the leaching solution through microwave leaching processes while they are released to the environment through a microwave heating processes.

요약
 ABSTRACT
 서 론
 실험재료 및 방법
  황화광물 정광시료
  마이크로웨이브 용출 실험
 결과 및 고찰
  마이크로웨이브 Bi,As 제거온도 및 광물학적상변화
  마이크로웨이브 질산용출에 따른 조사시간효과
  마이크로웨이브 질산용출에 따른 질산농도효과
  마이크로웨이브 질산용출 실험에 따른 고액비효과
 결 론
 REFERENCES

• 온현성(조선대학교 에너지⋅자원공학과) | Hyun-Sung On (Department of Energy and Resource Engineering, Chosun University)
• 톡토흐마(조선대학교 에너지⋅자원공학과) | B. Togtokhmaa (Department of Energy and Resource Engineering, Chosun University)
• 박천영(조선대학교 에너지⋅자원공학과) | Cheon-Young Park (Department of Energy and Resource Engineering, Chosun University) Corresponding author