전자스크랩으로부터 용매추출 및 사이클론 전해에 의한 고순도 은(Ag) 회수 Recovery of high purity silver(Ag) by solvent extraction and cyclone electrowinning from electronic scraps원문보기
전자스크랩으로부터 침출, 용매추출, 사이클론전해채취를 이용하여 은을 고순도로 분리하기 위한 기초 연구를 실시하였다. 파·분쇄한 전극공정부산물에 함유된 은을 용액 중으로 침출시키기 위해 침출액 종류, 침출액 농도를 실험 변수로 하여 침출 거동을 고찰하였다. 염산과 ...
전자스크랩으로부터 침출, 용매추출, 사이클론전해채취를 이용하여 은을 고순도로 분리하기 위한 기초 연구를 실시하였다. 파·분쇄한 전극공정부산물에 함유된 은을 용액 중으로 침출시키기 위해 침출액 종류, 침출액 농도를 실험 변수로 하여 침출 거동을 고찰하였다. 염산과 질산으로 은을 침출한 결과 질산을 사용하였을 때 은의 용해도가 더 우수하였고, 질산 농도 5.0M에서 은이 376.07ppm으로 가장 많이 침출되었다. 침출후액에서 유기 추출제인 Cyanex 301을 사용하여 은을 선택적으로 추출하고자 하였으며, 침출액 중 질산농도와 추출제인 Cyanex301의 농도, 상비(A/O)를 변수로 은과 다른 불순물의 추출 거동을 살펴보았다. 3.0M 질산 침출후액을 수상으로 사용하여 10% Cyanex 301과 상비(A/O) 2/1로 혼합하여 추출 실험한 결과 2단 추출에 의해 590.3ppm Ag, 32.26ppm Ca, 6.14ppm Fe, 34.02ppm Sr이 추출되었다. 세정공정을 통해 은 이외에 공추출된 불순물인 Ca, Fe, Sr을 제거하기 위해 3.0M 염산으로 세정하여, 약 1%의 은 세정율을 보였으며 불순물인 Ca, Fe, Sr은 97% 이상 세정되어 효과적으로 불순물을 제거할 수 있었다. 세정 후 유기상에 남아있는 은을 수상으로 이동시키기 위해 탈거하였으며, 0.5M 티오요소, 0.1M 염산, 상비(O/A) 2/1의 실험조건으로 1단 탈거에 의해 은이 약 84% 탈거되어 탈거 후액 중 은의 농도가 약 1.0 g/L인 용액을 얻었다. 탈거 후액을 전해액으로 사용하여 사이클론 전해채취법을 이용하여 은을 금속형태로 회수하고자 하였다. 실험에는 직접 제작한 사이클론 전해조를 사용하였으며 유량, 전류밀도, 전해액 중 초기 은 농도로 실험을 진행하였다. 유량의 경우 12L/min.에서 98% 이상의 은 회수율을 보였고 은 석출물은 분말 형태의 순은으로 회수되었다. 전류밀도가 증가할수록 은의 회수속도가 증가하였으며 0.5 A/dm2(ASD)에서 은 회수율과 전류효율이 높았다. 전해액 중 초기 은 농도가 1.0 g/L 이상인 경우 재용해가 일어나지 않았고, 은 농도가 증가할수록 음극전류효율이 증가하였으며, 판상의 은을 회수할 수 있었다. 또한 유량 12L/min, 전류밀도 0.5A/dm2, 1.0g/L Ag, 35℃의 실험조건에서 회수된 은의 순도는 99.95%였다.
전자스크랩으로부터 침출, 용매추출, 사이클론 전해채취를 이용하여 은을 고순도로 분리하기 위한 기초 연구를 실시하였다. 파·분쇄한 전극공정부산물에 함유된 은을 용액 중으로 침출시키기 위해 침출액 종류, 침출액 농도를 실험 변수로 하여 침출 거동을 고찰하였다. 염산과 질산으로 은을 침출한 결과 질산을 사용하였을 때 은의 용해도가 더 우수하였고, 질산 농도 5.0M에서 은이 376.07ppm으로 가장 많이 침출되었다. 침출후액에서 유기 추출제인 Cyanex 301을 사용하여 은을 선택적으로 추출하고자 하였으며, 침출액 중 질산농도와 추출제인 Cyanex301의 농도, 상비(A/O)를 변수로 은과 다른 불순물의 추출 거동을 살펴보았다. 3.0M 질산 침출후액을 수상으로 사용하여 10% Cyanex 301과 상비(A/O) 2/1로 혼합하여 추출 실험한 결과 2단 추출에 의해 590.3ppm Ag, 32.26ppm Ca, 6.14ppm Fe, 34.02ppm Sr이 추출되었다. 세정공정을 통해 은 이외에 공추출된 불순물인 Ca, Fe, Sr을 제거하기 위해 3.0M 염산으로 세정하여, 약 1%의 은 세정율을 보였으며 불순물인 Ca, Fe, Sr은 97% 이상 세정되어 효과적으로 불순물을 제거할 수 있었다. 세정 후 유기상에 남아있는 은을 수상으로 이동시키기 위해 탈거하였으며, 0.5M 티오요소, 0.1M 염산, 상비(O/A) 2/1의 실험조건으로 1단 탈거에 의해 은이 약 84% 탈거되어 탈거 후액 중 은의 농도가 약 1.0 g/L인 용액을 얻었다. 탈거 후액을 전해액으로 사용하여 사이클론 전해채취법을 이용하여 은을 금속형태로 회수하고자 하였다. 실험에는 직접 제작한 사이클론 전해조를 사용하였으며 유량, 전류밀도, 전해액 중 초기 은 농도로 실험을 진행하였다. 유량의 경우 12L/min.에서 98% 이상의 은 회수율을 보였고 은 석출물은 분말 형태의 순은으로 회수되었다. 전류밀도가 증가할수록 은의 회수속도가 증가하였으며 0.5 A/dm2(ASD)에서 은 회수율과 전류효율이 높았다. 전해액 중 초기 은 농도가 1.0 g/L 이상인 경우 재용해가 일어나지 않았고, 은 농도가 증가할수록 음극전류효율이 증가하였으며, 판상의 은을 회수할 수 있었다. 또한 유량 12L/min, 전류밀도 0.5A/dm2, 1.0g/L Ag, 35℃의 실험조건에서 회수된 은의 순도는 99.95%였다.
Leaching, solvent extraction and cyclone electrowinning are used to separate high-purity of silver from electronic scrap. To leach the silver contained in crushed electronic scrap into solution, the leaching behavior was investigated using the type of leaching solution and its concentration as exper...
Leaching, solvent extraction and cyclone electrowinning are used to separate high-purity of silver from electronic scrap. To leach the silver contained in crushed electronic scrap into solution, the leaching behavior was investigated using the type of leaching solution and its concentration as experimental parameters. Experiments in which silver was leached with hydrochloric acid and nitric acid revealed that the solubility of silver was better when nitric acid was used; the highest leached silver concentration was 370.07 ppm of silver with a nitric acid concentration of 5.0M. In the leaching solution, silver was selectively extracted with Cyanex 301, which is an organic extract, and the extraction behavior of silver and other impurities were examined by varying the concentration of nitric acid in the leaching solution, the concentration of Cyanex 301 as an extractant, and the phase ratio(A/O). The use of 3.0M nitrate leachate, 10% Cyanex 301, and an A/O ratio of 2:1 led to the extraction of 590.3ppm Ag, 32.26ppm Ca, 6.14ppm Fe, and 34.02ppm Sr. In addition, silver was washed with 3.0M hydrochloric acid to remove Ca, Fe, and Sr, which were co-extracted impurities. As a results, a silver scrubbing rate of approximately 1% was observed and more than 97% of impurities of Ca, Fe, Sr were effectively removed. After the scrubbing procedure, the stripping experiment was carried out to transfer the silver remaining in the organic phase to the aqueous phase. Approximately 84% of the silver was stripped by one-stage stripping, and a silver concentration of about 1.0g/L in the stripping solution was obtained under the experimental conditions of 0.5M thiourea, 0.1M hydrochloric acid, and an O/A ratio of 2:1. To recover metallic silver from the stripping solution, cyclone electrowinning method was used. Experiments were performed using a cyclone electrowinning cell, which was directly manufactured; the experimental parameters were flux, current density, and initial silver concentration in the electrolyte. At a flux of 12L/min, a silver recovery of more than 98% was obtained and the silver precipitate was recovered as pure silver powder. As the current density increased, the recovery rate of silver increased. The silver recovery and current efficiency were higher at a current density of 0.5A/dm2 than under the other investigated conditions. When initial concentration of the electrolyte was more than 1.0g/L, re-dissolution did not occur. As the concentration of silver increased, the cathodic current efficiency increased and the plate form of silver could be recovered. The purity of silver recovered under experimental conditions with flux of 12L/min, current density of 0.5A/dm2, 1.0g/L Ag and 35℃ was 99.95%.
Leaching, solvent extraction and cyclone electrowinning are used to separate high-purity of silver from electronic scrap. To leach the silver contained in crushed electronic scrap into solution, the leaching behavior was investigated using the type of leaching solution and its concentration as experimental parameters. Experiments in which silver was leached with hydrochloric acid and nitric acid revealed that the solubility of silver was better when nitric acid was used; the highest leached silver concentration was 370.07 ppm of silver with a nitric acid concentration of 5.0M. In the leaching solution, silver was selectively extracted with Cyanex 301, which is an organic extract, and the extraction behavior of silver and other impurities were examined by varying the concentration of nitric acid in the leaching solution, the concentration of Cyanex 301 as an extractant, and the phase ratio(A/O). The use of 3.0M nitrate leachate, 10% Cyanex 301, and an A/O ratio of 2:1 led to the extraction of 590.3ppm Ag, 32.26ppm Ca, 6.14ppm Fe, and 34.02ppm Sr. In addition, silver was washed with 3.0M hydrochloric acid to remove Ca, Fe, and Sr, which were co-extracted impurities. As a results, a silver scrubbing rate of approximately 1% was observed and more than 97% of impurities of Ca, Fe, Sr were effectively removed. After the scrubbing procedure, the stripping experiment was carried out to transfer the silver remaining in the organic phase to the aqueous phase. Approximately 84% of the silver was stripped by one-stage stripping, and a silver concentration of about 1.0g/L in the stripping solution was obtained under the experimental conditions of 0.5M thiourea, 0.1M hydrochloric acid, and an O/A ratio of 2:1. To recover metallic silver from the stripping solution, cyclone electrowinning method was used. Experiments were performed using a cyclone electrowinning cell, which was directly manufactured; the experimental parameters were flux, current density, and initial silver concentration in the electrolyte. At a flux of 12L/min, a silver recovery of more than 98% was obtained and the silver precipitate was recovered as pure silver powder. As the current density increased, the recovery rate of silver increased. The silver recovery and current efficiency were higher at a current density of 0.5A/dm2 than under the other investigated conditions. When initial concentration of the electrolyte was more than 1.0g/L, re-dissolution did not occur. As the concentration of silver increased, the cathodic current efficiency increased and the plate form of silver could be recovered. The purity of silver recovered under experimental conditions with flux of 12L/min, current density of 0.5A/dm2, 1.0g/L Ag and 35℃ was 99.95%.
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