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Preparation of Nano-Sized Tin Oxide Powder from Waste Pb-Free Solder by Direct Nitric Acid Leaching
Yoo, Kyoungkeun,Lee, Kwangseok,Jha, Manis Kumar,Lee, Jae-Chun,Cho, Kuk American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.11
<P>Nano-sized tin oxide particles were prepared by nitric acid (HNO3) leaching of Pb-free solder containing tin (Sn), silver (Ag), and copper (Cu) as main components. During the nitric acid leaching, Ag and Cu were dissolved whereas Sn was not detected in the leach solution and the leaching efficiencies of Ag and Cu increased with increasing temperature and HNO3 concentration. The precipitates were analyzed with X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM). The tin precipitate was determined to be tin oxide by XRD and nano-sized particles were observed in the SEM and TEM images. The larger particle size was observed in the leaching condition of slow leaching rate. The purity and particle size of tin precipitate, obtained from the leaching test performed in the 2 mol/L HNO3 solution at 90 degrees C and 400 rpm, were 99.986% and 6.03 nm, respectively.</P>
Dissolution of Magnesium from Serpentine Mineral in Sulfuric Acid Solution
Yoo, Kyoungkeun,Kim, Byung-Su,Kim, Min-Seuk,Lee, Jae-chun,Jeong, Jinki The Japan Institute of Metals 2009 MATERIALS TRANSACTIONS Vol.50 No.5
<P>As the volume of CO<SUB>2</SUB>, one of greenhouse gases linked to global warming, in the atmosphere increases, there has been an increasing interest in CO<SUB>2</SUB> sequestration. Aqueous carbonation, which involves the extraction of Mg from serpentine minerals and the subsequent carbonation reaction with CO<SUB>2</SUB> to form the geologically stable mineral MgCO<SUB>3</SUB>, has been proposed as a promising CO<SUB>2</SUB> sequestration technology. This study investigates the dissolution of Mg from serpentine mineral in H<SUB>2</SUB>SO<SUB>4</SUB> solution. The study is part of a major research project aimed at developing an effective CO<SUB>2</SUB> sequestration technology using the serpentine mineral which is readily available in Korea. Complete dissolution of Mg from natural serpentine was achieved in 30 min at a temperature of 90°C under 0.5 M H<SUB>2</SUB>SO<SUB>4</SUB>. The rate of dissolution of Mg was independent of the agitation speed at speeds above 300 rpm. The fraction of Mg dissolved from milled serpentine was found to be a little higher than that from natural serpentine up to 70°C in 0.5 M H<SUB>2</SUB>SO<SUB>4</SUB>. The Jander equation was used to explain the dissolution rate data. The rate of Mg dissolution seemed to be limited by diffusion through the thin channels formed between the silica layers in the serpentine particles.</P>
암모니아 침출공정(浸出工程) 기술개발(技術開發) 동향(動向)
유경근,김현중,Yoo, Kyoungkeun,Kim, Hyunjung 한국자원리싸이클링학회 2012 資源 리싸이클링 Vol.21 No.5
암모니아 습식제련공정은 철과 칼슘의 용해를 억제하며 구리 등의 금속을 선택적으로 침출이 가능한 장점이 있어 구리, 금, 니켈 및 코발트 등의 금속을 선택적으로 침출하기 위한 연구가 수행되어왔다. 이 글에서는 모터스크랩과 폐인쇄회로기판으로부터 구리의 선택적 침출, 티오황산염 사용 등 시안의 대체 및 저감을 위한 금의 암모니아침출, 산화니켈광 및 망간단괴처리공정 중간산물로부터 니켈과 코발트를 회수하기 위한 암모니아침출 기술개발동향을 정리하고 국내 연구개발방향을 제시하고자 하였다. Selective leaching processes for copper, gold, nickel, and cobalt have been investigated because there is an advantage of ammoniacal hydrometallurgy that metal such as copper could be selectively extracted restricting the dissolution of iron or calcium. In the present article, the studies for selective ammoniacal leaching of copper from motor scraps and waste printed circuit boards (PCBs), for ammoniacal leaching of gold to decrease the amount of cyanide used or to substitute cyanide by thiosulfate, and for ammoniacal leaching to recover nickel and cobalt from nickel oxide ore and intermidiate obtained from manganese nodule treatment process were summarized and further studies were proposed for domestic technology development for ammoniacal hydrometallurgy processes.
Hydrochloric acid leaching behavior of metals from non-magnetic fraction of Pb dross
Sanghyeon Choi,Kyoungkeun Yoo,Richard Diaz Alorro 한국자원공학회 2019 Geosystem engineering Vol.22 No.6
The leaching behaviors of tin (Sn), antimony (Sb), iron (Fe), and lead (Pb) from non-magnetic fraction of Pb dross, which was obtained from magnetic separation process to remove As components, were investigated using HCl solution. The leaching efficiencies of Sn, Fe, and Pb increased with increasing agitation speed, temperature, and HCl concentration and with decreasing pulp density, but Sb was dissolved only in the 3 and 5 M HCl solutions. The leaching efficiencies of metals increased to 100% in the 5 M HCl solution at 400 rpm and 70°C with 1% pulp density within 120 min. In the case of leaching test with 1 M HCl, Sb components could be recovered as leach residue. After leaching test, Pb could be recovered as PbCl2 from the solution by lowering temperature. Tin ions were extracted selectively by solvent extraction with tri-butyl phosphate, remaining Fe and Pb ions in the solution. The process consisting of HCl leaching, precipitation, and solvent extraction recovers successfully Sb, Pb, and Sn from non-magnetic fraction of Pb dross.
지르코니아볼층 진동을 이용한 스파이스와 석회석 입자의 비중선별
유재경,이민지,김경환,유경근,Yoo, Jae Kyoung,Lee, Minji,Kim, Gyeong Hwan,Yoo, Kyoungkeun 한국자원리싸이클링학회 2020 資源 리싸이클링 Vol.29 No.3
In the present study, gravity separation of speiss (6.74 g/㎤) and limestone (2.7 g/㎤) was investigated using a vibrating 1 mm-zirconia ball (5.6 g/㎤) bed as a medium. The floating ratio and separation efficiency with increasing the number of spiess and limestone granules were examined by changing the vibration frequency from 18 Hz to 26 Hz. During the vibration, the zirconia balls circulate inside the vessel, and the spiess granules sink with the zirconia balls, but limestone granules remain on the surface of the zirconia ball bed. As the number of particles of spiess and limestone granules increased, it was observed that the granules were congested in the path of the granule sinking, so the rate of particle sinking decreased, and that limestone granules overlapping with the spiess granule also sunk. Therefore, the separation efficiency decreases with increasing the number of granules, but when the vibrational frequency increases, there is no more congestion and the separation efficiency increases. When each of the three particles was added, a separation efficiency of 100% was acheived at 22 Hz, which indicates that a dry gravity separation process that does not require a drying process is possible.
염화주석용액을 이용한 폐인쇄회로기판으로부터 부품의 분리
박유진,유경근,Park, Yujin,Yoo, Kyoungkeun 한국자원리싸이클링학회 2021 資源 리싸이클링 Vol.30 No.2
Dismantling tests were performed to separate components from waste printed circuit boards (PCBs) using HCl solution with Sn4+. Then, the effects of agitation speed, reaction temperature, initial Sn4+ concentration, and HCl concentration on the dismantling of components were investigated. No significant effect on the dismantling speed was observed upon changing the agitation speed from 100 to 300 rpm. However, the dismantling rate increased with increasing reaction temperature, Sn4+ concentration, and HCl concentration. In the all-component dismantling tests, when the dismantling ratio increased to 100%, no solder was observed on the boards, and the Sn4+ concentration was ~1,500 mg/L. The dismantling ratio of the components from the PCB increased to 100% within 2 h when 1 mol/L HCl solution with 10,000 mg/L Sn4+ was used at an agitation speed and temperature of 200 rpm and 90 ℃, respectively.
Lim Yoojin,Choi Jaewoo,Yoo Kyoungkeun,Lee Sang-Hun 한국자원공학회 2022 Geosystem engineering Vol.25 No.6
Vanadium in the vanadium-bearing titanomagnetite (VTM) exist by replacing iron in the magnetite crystal, and magnetite should be recovered separately from titanium components in the vanadium- bearing titanomagnetite. In the present study, a sensing system was proposed by measuring magnetic susceptibility of magnetite because the magnetic susceptibility can be easily and quickly measured. The effects of mixing ratio of magnetite and ilmenite with silica and the distance between the magnetic susceptibility meter and the sample bed on the magnetic susceptibility were investigated. The magnetic susceptibility of the mixture of magnetite and ilmenite with 0.1 g or 0.2 g of silica decreased with increasing the ratio of ilmenite in the mixture, but the effect of silica addition was not significant. When the distance between the magnetic susceptibility meter and the sample bed increased, the magnetic susceptibility of magnetite decreased, but the magnetic susceptibility decreased with increasing the thickness of magnetite sample bed of magnetite. Because the magnetic susceptibility depended strongly on the content of magnetite, the sensing system using the magnetic susceptibility measurement could be successfully applied to detect magnetite.