폐 인쇄회로기관의 층 분리를 이용한 금속과 플라스틱의 분리

( Manis Kumar Jha ),유재민 ( Jae Min Yoo ),이재천 ( Jae Chun Lee ),정진기 ( Jin Ki Jeong ) 한국공업화학회 2008 응용화학 Vol.12 No.1

폐 인쇄회로기판의 층 분리를 이용한 금속과 플라스틱의 분리

정진기,( Manis Kumar Jha ),유재민,이재천 한국공업화학회 2008 한국공업화학회 연구논문 초록집 Vol.2008 No.-

黃酸에 의한 輝水鉛石의 焙燒精鑛으로부터 銅의 除去

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.

구리 회수를 위한 식물뿌리 기반 친환경 바이오 흡착제의 적용 – 합성수지와의 비교

Shilpa K. Bawkar,Manis K. Jha,Pankaj K. Choubey,Rukshana Parween,Rekha Panda,Pramod K. Singh,이재천 한국자원리싸이클링학회 2022 資源 리싸이클링 Vol.31 No.4

Copper is one of the non-ferrous metals used in the electrical/electronic manufacturing industries due to its superior properties particularly the high conductivity and less resistivity. The effluent generated from the surface finishing process of these industries contains higher copper content which gets discharged in to water bodies directly or indirectly. This causes severe environmental pollution and also results in loss of an important valuable metal. To overcome this issue, continuous R & D activities are going on across the globe in adsorption area with the purpose of finding an efficient, low cost and ecofriendly adsorbent. In view of the above, present investigation was made to compare the performance of a plant root (Datura root powder) as a bio-adsorbent to that of the synthetic one (Tulsion T-42) for copper adsorption from such effluent. Experiments were carried out in batch studies to optimize parameters such as adsorbent dose, contact time, pH, feed concentration, etc. Results of the batch experiments indicate that 0.2 g of Datura root powder and 0.1 g of Tulsion T-42 showed 95% copper adsorption from an initial feed/solution of 100 ppm Cu at pH 4 in contact time of 15 and 30 min, respectively. Adsorption data for both the adsorbents were fitted well to the Freundlich isotherm. Experimental results were also validated with the kinetic model, which showed that the adsorption of copper followed pseudo-second order rate expression for the both adsorbents. Overall result demonstrates that the bio-adsorbent tested has a potential applicability for metal recovery from the waste solutions/effluents of metal finishing units. In view of the requirements of commercial viability and minimal environmental damage there from, Datura root powder being an effective material for metal uptake, may prove to be a feasible adsorbent for copper recovery after the necessary scale-up studies. 구리는 우수한 특성, 특히 높은 전도성과 낮은 저항으로 인해 전기/전자 제조 산업에 널리 사용되는 비철금속 중 하나이다. 이러한 산업의 표면 처리 공정에서는 구리 함량이 높은 폐수가 발생하며, 직간접적으로 수계로 배출된다. 이는 심각한 환경 오염을 일으키고 또한귀중한 유용금속의 손실을 초래한다. 이러한 문제를 극복하기 위하여, 효율적이고 저렴하며 친환경적인 흡착제를 찾기 위한 목적으로 흡착 분야에서 전 세계적으로 지속적인 연구개발이 진행되고 있다. 이러한 점을 고려하여, 본 연구에서는 위와 같은 폐수로부터 구리 흡착을 위한 바이오 흡착제로서 식물뿌리(Datura 뿌리 분말)의 성능을 합성 흡착제(Tulsion T-42)와 비교하였다. 실험은 흡착제 투여량, 접촉시간, pH, 주입액 농도 등의 변수들을 최적화하기 위하여 회분식으로 수행되었다. 초기구리농도가 100 ppm이고 pH가 4인 주입액에서, 0.2 g Datura 뿌리 분말을 15분간 접촉하였을 때 구리 흡착율은 95%이었으며, 0.1 g Tulsion T-42은 30분간 접촉에서 95%의 흡착율을 나타내었다. 두 흡착제의 흡착 데이터는 Freundlich 등온선과 잘 일치하였으며, 유사 2차 속도식을 따르는 것을 나타내었다. 전체 결과는 본연구의 바이오 흡착제가 표면처리 공정의 폐액 또는 폐수로부터 금속 회수에 적용될 가능성을 보여주고 있다.

Thermal treatment for the separation of phosphate and recovery of rare earth metals (REMs) from Korean monazite

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.

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.

Thermal treatment for the separation of phosphate and recovery of rare earth metals (REMs) from Korean monazite

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>

Top submerged lance 로의 스파이스산물 중 구리의 황산 침출에 대한 납과 안티몬의 영향

채수진,유경근,Richard Diaz Alorro,Manis Kumar Jha 대한금속·재료학회 2021 대한금속·재료학회지 Vol.59 No.1

Cu-Pb and Cu-Sb alloys were prepared at various ratios, from 10:90 to 90:10, and leaching tests with sulfuric acid were conducted to investigate the effect of Pb and Sb on the leaching of Cu from speiss, which is obtained from the top submerged lance furnace process. The Cu leaching efficiency increased as the amount of Cu increased in both alloys, but the leaching efficiencies were lower in the Cu-Sb alloy than in the Cu-Pb alloy. For example, in alloys with 70% Pb and Sb ratio, the leaching efficiency of Cu from the Cu-Pb alloy increased to 95%. The leaching efficiency of the Cu-Sb alloy was 67% in 2 mol/L sulfuric acid solution with 1% pulp density and 1000cc/min O2 at 90 °C, 400 rpm, and 6 hours. When the leaching residues were examined with SEM (scanning electron microscopy)-EDS (Energy-dispersive X-ray spectroscopy), it was found that in all Cu-Pb alloys, Cu and Pb exist as independent metal phases, while, in Cu-Sb alloys, Cu formed intermetallic compounds with Sb such as Cu2Sb, because the Cu-Sb alloy has a lower melting point than the Cu-Pb alloy. These results suggest that Sb may retard the leaching rate of Cu from the alloy. When the leaching residue of speiss obtained from a top submerged lance furnace, intermetallic alloys of Cu-Sb were also observed, having a net structure. The net structure contains Cu metal in the center of the speiss particle, while the intermetallic alloys of Cu-Sb were present in the outer layer of the particle, in good agreement with the results using the alloys in this study. This suggests the intermetallic alloys of Cu-Sb can prevent copper from leaching.

Recycling of gold from waste electronic components of devices

Rekha Panda,Om Shankar Dinkar,Manis Kumar Jha,Devendra Deo Pathak 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.1

Tremendous generation of e-waste and its illegal recycling are causing immense threat to environment as well as the loss of precious metals. The present research reports a novel hybrid process for the total recovery of gold from small depopulated components of e-waste. Connectors and integrated circuits (ICs) liberated from printed circuit boards (PCBs) were pulverized and processed for gold leaching using 10 g/L sodium cyanide solution at 40 oC and mixing time 15 min, where more than 95% gold was found to be leached out in single stage. From the obtained leach liquor, gold metal was recovered by charcoal adsorption followed by heat treatment. The raffinate left after adsorption of gold was found to contain ~10mg/L gold, which was also recovered using Amberlite IRA 400Cl at equilibrium pH 9.6 in 30 min maintaining aqueous/resin (A/R) ratio 25 mL/g. The raffinate solution was enriched to 882.41mg/L and the solution was further processed to get metal/salt using cementation/ evaporation. Obtained leached residue is processed for non-ferrous metals recovery and finally disposed-off after treatment and TCLP test. The effluent left after leaching could be easily decomposed and treated in ETP using standard environmental procedure.