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Recycling of printed circuit boards (PCBs) to generate enriched rare metal concentrate
Kumar, Vinod,Lee, Jae-chun,Jeong, Jinki,Jha, Manis Kumar,Kim, Byung-su,Singh, Ratnakar Elsevier 2015 Journal of industrial and engineering chemistry Vol.21 No.-
<P><B>Abstract</B></P> <P>An eco-friendly process for recycling obsolete PCBs to get enriched rare-metal concentrate using physical separation technique is discussed. Metal concentration in digital video disc (DVD) PCBs is ∼43wt.% whereas in vacuum cleaner (VC) PCBs ∼30wt.% with rare metal of ∼ 2.8%. Concentrate grade of ∼88% total metals including ∼5.85% rare metals in-case of DVD-PCBs while ∼90% of total metals including ∼2.81% rare metals in-case of VC-PCBs was achieved by froth flotation. While ∼75% total metals including ∼9.41% rare metals for DVD-PCBs and ∼65% total metals including ∼5.10% rare metals for VC-PCBs was obtained by pneumatic separation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High metal recovery achieved from PCBs of EOL-DVD and EOL-VC. </LI> <LI> The evolved process doesn’t require any chemical reagents. </LI> <LI> The process is eco-friendly and economical with no recurring cost. </LI> <LI> Re-circulating and water conservation in close-loop nutsche filtration. </LI> <LI> Enriched metallic concentrate is suitable for hydrometallurgical purification. </LI> </UL> </P>
Recycling of printed circuit boards (PCBs) to generate enriched rare metal concentrate
Vinod Kumar,이재천,정진기,Manis Kumar Jha,김병수,Ratnakar Singh 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1
An eco-friendly process for recycling obsolete PCBs to get enriched rare-metal concentrate usingphysical separation technique is discussed. Metal concentration in digital video disc (DVD) PCBs is43 wt.% whereas in vacuum cleaner (VC) PCBs 30 wt.% with rare metal of 2.8%. Concentrate grade of88% total metals including 5.85% rare metals in-case of DVD-PCBs while 90% of total metalsincluding 2.81% rare metals in-case of VC-PCBs was achieved by froth flotation. While 75% totalmetals including 9.41% rare metals for DVD-PCBs and 65% total metals including 5.10% rare metalsfor VC-PCBs was obtained by pneumatic separation.
김병수,Manis Kumar Jha,유경근,정진기,이재천 한국자원공학회 2007 한국자원공학회지 Vol.44 No.3
It is very important to remove copper from roasted molybdenite concentrate for making molybdenum oxide which is required for the production of alloyed steel. In the paper, a study for removing copper from roasted molybdenite concentrate by sulfuric acid leaching was carried out. From the experiments, it was found that the optimum condition for removing copper is the sulfuric acid of 1.5 vol.%, the leaching temperature of 25℃, the S/L ratio of 1,000 g/L, and the leaching time of 30 minutes. It was also verified that the recovery efficiency of molybdenum was improved by holding the leach liquor up to 30 minutes after leaching. The leach residue obtained at the optimum condition contains over 80% MoO3 and below 0.5% Cu, which could be used for the production of alloyed steel. At the optimum condition, the recovery ratio of molybdenum was 98~99%. Also, copper could be recovered from the leach liquor by cementation method using iron sheets as a reducing agent. 휘수연석의 배소정광으로부터 제강용 산화몰리브덴(MoO3) 분말을 제조하기 위해서는 동을 제거하는 것이 매우 중요하다. 본 연구에서는 황산침출에 의하여 휘수연석의 배소정광으로부터 동을 침출, 제거하는 연구를 수행하였다. 실험 결과 휘수연석의 배소정광으로부터 동을 효과적으로 침출, 제거하기 위한 최적침출조건은 황산농도 1.5 vol.%, 침출온도 25℃, 고액비 1,000 g/L, 침출시간 30분인 것으로 나타났다. 또한 침출반응 종료 후 30분 이상 정치함으로서 몰리브덴의 회수율이 향상되는 것으로 나타났다. 최적조건에서 침출잔사로 회수된 산화몰리브덴의 분말은 80% 이상 MoO3, 0.5% 미만 Cu를 함유함으로서 제강용 합금원소로 사용이 가능한 것으로 분석되었다. 최적조건에서 침출잔사로 회수된 Mo의 회수율은 98~99%이였으며, 침출액에 존재하는 동은 철을 환원제로 사용하는 시멘테이션 방법으로 회수할 수 있었다.
Leaching of rare earth metals (REMs) from Korean monazite concentrate
Rekha Panda,Manis Kumar Jha,이진영,Archana Kumari,Jhumki Hait,Vinay Kumar,J. Rajesh Kumar 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4
Systematic scientific studies for dephosphorization and acid leaching of Korean monazite are reported here. 50% NaOH (w/v) solubilizes 99.99% phosphate, at 170 ℃, 100 g/L pulp density in 4 h. Kinetics of phosphate leaching fitted well with model ‘‘chemical reaction control,’’ i.e. 1 - (1 - X)1/2 = kct, Ea = 58.04 kJ/mol. Further, rare earth hydroxides (REHs) was leached using 6 N HCl at 90 ℃, 60 g/L pulp density for 2 h to recover ~95% REMs. Leach liquor generated can be further processed using solvent extraction/ion exchange techniques. From the pure solutions, metal/salts could be obtained using evaporation, precipitation, etc.
Kumari, Archana,Panda, Rekha,Jha, Manis Kumar,Lee, Jin Young,Kumar, J. Rajesh,Kumar, Vinay Elsevier 2015 Journal of industrial and engineering chemistry Vol.21 No.-
<P><B>Abstract</B></P> <P>Systematic study for thermal decomposition of monazite to remove phosphate as a valuable product using Na<SUB>2</SUB>CO<SUB>3</SUB> and NaOH roasting processes to validate the TG/DTA studies is reported here. Monazite in 1:1wt. ratio with Na<SUB>2</SUB>CO<SUB>3</SUB> and NaOH requires a temperature of 900°C and 400°C, respectively, for 120min in order to achieve complete conversion of rare earth phosphate into its oxides. The roasted mass was washed, dried and leached in 6M HCl for 2h, pulp density 30g/L at 80°C which results in >90% REMs recovery. Leach liquor generated will be further processed by solvent extraction and precipitation processes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effective process for separation and recovery of rare earth metals. </LI> <LI> Alkaline thermal treatment under optimized condition is used to dephosphorize monazite. </LI> <LI> 99% phosphate was separated and recovered as value added product of sodium tri-phosphate. </LI> <LI> The oxide of rare earth concentrate was leached in chloride medium to recover high percentage of rare earth metals. </LI> </UL> </P>
Archana Kumari,Rekha Panda,Manis Kumar Jha,이진영,J. Rajesh Kumar,Vinay Kumar 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1
Systematic study for thermal decomposition of monazite to remove phosphate as a valuable productusing Na2CO3 and NaOH roasting processes to validate the TG/DTA studies is reported here. Monazite in1:1 wt. ratio with Na2CO3 and NaOH requires a temperature of 900 8C and 400 8C, respectively, for120 min in order to achieve complete conversion of rare earth phosphate into its oxides. The roastedmass was washed, dried and leached in 6 M HCl for 2 h, pulp density 30 g/L at 80 8C which results in>90% REMs recovery. Leach liquor generated will be further processed by solvent extraction andprecipitation processes.
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>
Treatment of industrial effluent to reclaim copper using adsorption technique
Bawkar Shilpa Kalamani,Choubey Pankaj Kumar,Parween Rukshana,Panda Rekha,Singh Pramod Kumar,Jha Manis Kumar,Lee Jae-chun 한국자원공학회 2022 Geosystem engineering Vol.25 No.4
Effluent generated during metal finishing in industries contains large amount of heavy metals, which get discharged into water bodies and creates environmental pollution as well as loss of metal values. Present studies report the adsorption of copper (Cu) from the effluent using Tulsion T-42 resin. Experiments were carried out for the adsorption of Cu from the effluent of Chemical and Mechanical Polishing (CMP) industries using cationic resin Tulsion T-42 (adsorbent). To get the optimized adsorption condition for copper the studies were carried out with varying process parameters i.e., contact time, adsorbent dose, pH, etc. Result of the batch experiments shows that 95% copper was adsorbed from the effluent containing 100 ppm copper using 0.1 g Tulsion T-42 in 50 mL feed solution at pH 4.0 in contact time of 30 min. The obtained data from Cu adsorption studies fitted well with Freundlich adsorption isotherm and followed second-order rate reaction. The 99% copper was found to be eluted from loaded adsorbent using 10% sulfuric acid in 60 min contact time. FT-IR result confirmed that complex with active sulphonic group of Tulsion T-42 was formed. The findings of the studies will be useful for the reclamation of copper from the waste water of metal finishing industries.