• 분석과학
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• 제37권1호
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• pp.47-62
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• 2024

Abu Gurdi area is located in the South-eastern Desert of Egypt which considered as volcanic massive sulfide deposits (VMS). The present work aims at investigating the ore mineralogy of Abu Gurdi region in addition to the effectiveness of the hydrometallurgical route for processing these ores using alkaline leaching for the extraction of Zn, Cu, and Pb in the presence of hydrogen peroxide, has been investigated. The factors affecting the efficiency of the alkaline leaching of the used ore including the reagent composition, reagent concentration, leaching temperature, leaching time, and Solid /Liquid ratio, have been investigated. It was noted that the sulfide mineralization consists mainly of chalcopyrite, sphalerite, pyrite, galena and bornite. Gold is detected as rare, disseminated crystals within the gangue minerals. Under supergene conditions, secondary copper minerals (covellite, malachite, chrysocolla and atacamite) were formed. The maximum dissolution efficiencies of Cu, Zn, and Pb at the optimum leaching conditions i.e., 250 g/L NaCO₃ - NaHCO₃ alkali concentration, for 3 hr., at 250 ℃, and 1/5 Solid/liquid (S/L) ratio, were 99.48 %, 96.70 % and 99.11 %, respectively. An apparent activation energy for Zn, Cu and Pb dissolution were 21.599, 21.779 and 23.761 kJ.mol^-1, respectively, which were between those of a typical diffusion-controlled process and a chemical reaction-controlled process. Hence, the diffusion of the solid product layer contributed more than the chemical reaction to control the rate of the leaching process. High pure Cu(OH)₂, Pb(OH)₂, and ZnCl₂ were obtained from the finally obtained leach liquor at the optimum leaching conditions by precipitation at different pH. Finally, highly pure Au metal was separated from the mineralized massive sulfide via using adsorption method.

• 분석과학
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• 제37권1호
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• pp.63-78
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• 2024

The continuous increasing of the global demand of copper and nickel metals raises the interest in developing alternative technologies to produce them from copper sulfide ore. Also, in line with Egypt's vision 2030 for achieving the sustainable socioeconomic development which aims at developing alternative and eco-friendly technologies for processing the Egyptian ores to produce these strategic products instead of its importing. These metals enhance the advanced electrical and electronic industries. The current work aims at investigating the recovery of copper and nickel from Abu Swayeil copper ore using pug leaching technique by sulfuric acid. The factors affecting the pug leaching process including the sulfuric acid concentration, leaching time and temperature have been investigated. The copper ore sample was characterized chemically using X-ray fluorescence (XRF) and scanning electron microscope (SEM-EDX). A response surface methodology develops a quadratic model that expects the nickel and copper leaching effectiveness as a function of three controlling factors involved in the procedure of leaching was also investigated. The obtained results showed that the maximum dissolution efficiency of Ni and Cu are 99.06 % and 95.30%, respectively which was obtained at the following conditions: 15 % H₂SO₄ acid concentration for 6 hr. at 250 ℃. The dissolution kinetics of nickel and copper that were examined according to heterogeneous model, indicated that the dissolution rates were controlled by surface chemical process during the pug leaching. The activation energy of copper and nickel dissolution were 26.79 kJ.mol^-1 and 38.078 kJ.mol^-1 respectively; and the surface chemical was proposed as the leaching rate-controlling step.

• 한국지구과학회지
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• 제35권6호
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• pp.401-411
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• 2014

Au 정광으로부터 Au Ag의 용출율을 향상시키기 위하여 기계적-화학적 활성화와 티오요소-티오시안산염 혼합용액을 적용하였다. 기계적-화학적 활성화를 이루기 위하여 정광 시료를 건식으로 그리고 습식으로 미분쇄하였다. 입도분포 분석과 XRD 분석 결과, 평균 입도 크기와 결정크기는 정광 시료보다 건식-시료에서 그리고 건식-시료보다 습식-시료에서 더 작게 나타났다. SEM과 XRD 분석 결과 기계적-화학적 활성화에 의해서 습식-시료에서 비정질화 현상이 관찰되었다. Au Ag에 대한 용출실험을 티오요소 용액, 티오시안산염 용액 그리고 티오요소-티오시안산염 혼합 용액으로 각각 수행하였다. Au Ag 용출율은 정광 시료보다 건식-시료에서 그리고 건식-시료보다 습식-시료에서 더 높게 나타났다. Au Ag는 티오요소 용액에서 보다 티오시안산염 용액에서 그리고 티오시안산염 용액에서보다 티오요소-티오시안산염 혼합 용액에서 더 높게 용출되었다. 습식-시료와 티오요소-티오시안산염 혼합 용액을 적용할 때 Au Ag가 99% 이상으로 용출되었다.

• 한국융합학회논문지
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• 제7권1호
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• pp.155-160
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• 2016

청양지역 폐광산의 오염원인인 중금속의 제거를 침출과 이온교환법을 활용한 융합공정을 통해 실험하였으며 중금속에 오염된 토양시료는 통계처리를 하여 분석하였다. 오염토양은 일차로 부선처리법으로 분리하였으며, 사용시약이 증가할수록 선별지수는 증가하였다. 중금속을 제거하기 위한 침출과 이온분리법에 의해 선별도는 더 향상이 되었다. 침출속도는 황산용액이 증가할수록 증가되었으며, 침출용액은 이온교환법에 의해 상당부분 제거가 되었다. 침출과 이온교환법이 결합된 연속융합공정을 개발하여 중금속 제거 실험을 하였으며, 향후 개선을 통해 중금속의 제거효과가 향상될 것이며, 이를 통해 폐광산의 오염토양에 적용 가능함을 알 수 있었다.

• 한국환경과학회지
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• 제24권2호
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• pp.245-251
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• 2015

The main objective of this study is to recovery valuable metals with metal particle size distributions in waste cell phone PCBs(Printed Circuit Boards) by means of pulverization and nitric acid process. The particle size classifier also was evaluated by specific metal contents. The PCBs were pulverized by a fine pulverizer. The particle sizes were classified by 5 different sizes which were PcS1(0.2 mm below), PcS2(0.20~0.51 mm), PcS3(0.51~1.09 mm), PcS4(1.09~2.00 mm) and PcS5(2.00 mm above). Non-magnetic metals in the grinding particles were separated by a hand magnetic. And then, Cu, Co and Ni were separated by 3M nitric acid. Particle diameter of PCBs were 0.388~0.402 mm after the fine pulverizer. The sorting coefficient were 0.403~0.481. The highest metal content in PcS1. And the bigger particle diameter, the lower the valuable metals exist. The recovery rate of the valuable metals increases in smaller particle diameter with same leaching conditions. For further work, it could improve to recovery of the valuable metals effectively by means of individual treatment, multistage leaching and different leaching solvents.

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2005년도 추계정기총회 및 제26회 학술발표대회 고분자리싸이클링기술 특별심포지엄
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• pp.304-307
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• 2005

Printed circuit boards (PCBs) of the printer are composed of various organic and inorganic compounds as well as metals and alloys. This study was conducted to recover valuable metals from used PCBS by physical separation and leaching. The PCBs was crushed, sieved, classified by zig zag classifier and magnetic constituents were removed by the magnetic separation. The non-magnetic constituents of sizes between 1.2 and 0.6 mm especially containing high quantity of Cu (e.g. 83% on metal base and 31% on total base) were used for the leaching experiment. The effect of the nature and concentration of acids and reaction temperature were investigated. The Cu leaching rate to 98.5% in 2M nitric acid, pulp density 100g/L, $90^{\circ}C$, 300rpm, 1hr leaching.

• International Journal of Concrete Structures and Materials
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• 제9권3호
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• pp.295-306
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• 2015

Simulating natural leaching process for cementitious materials is essential to perform long-term safety assessments of repositories for nuclear waste. However, the current test methods in literature are time consuming, limited to crushed material and often produce small size samples which are not suitable for further testing. This paper presents the results from the study of the physical (gas permeability as well as chloride diffusion coefficient) and mechanical properties (tensile and compressive strength and elastic modulus) of solid cementitious specimens which have been depleted in calcium by the use of a newly developed method for accelerated calcium leaching of solid specimens of flexible size. The results show that up to 4 times increase in capillary water absorption, 10 times higher gas permeability and at least 3 times higher chloride diffusion rate, is expected due to complete leaching of the Portlandite. This coincides with a 70 % decrease in mechanical strength and more than 40 % decrease in elastic modulus.

• Nuclear Engineering and Technology
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• 제51권3호
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• pp.755-760
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• 2019

Compound samples based on the mineral-like magnesium potassium phosphate matrix $MgKPO_4{\times}6H_2O$ were synthesized by solidification of high level waste surrogate. Phase composition and structure of synthesized samples were studied by XRD and SEM methods. Compressive strength of the compounds is $12{\pm}3MPa$. Coefficient of thermal expansion of the samples in the range $250-550^{\circ}C$ is $(11.6{\pm}0.3){\times}10^{-6}1/^{\circ}C$, and coefficient of thermal conductivity in the range $20-500^{\circ}C$ is $0.5W/(m{\times}K)$. Differential leaching rate of elements from the compound, $g/(cm^2{\times}day)$: $Mg-6.7{\times}10^{-6}$, $K-3.0{\times}10^{-4}$, $P-1.2{\times}10^{-4}$, $^{137}Cs-4.6{\times}10^{-7}$; $^{90}Sr-9.6{\times}10^{-7}$; $^{239}Pu-3.7{\times}10^{-9}$, $^{241}Am-9.6{\times}10^{-10}$. Leaching mechanism of radionuclides from the samples at the first 1-2 weeks of the leaching test is determined by dissolution ($^{137}Cs$), wash off ($^{90}Sr$) or diffusion ($^{239}Pu$ and $^{241}Am$) from the compound surface, and when the tests continue to 90-91 days - by surface layer depletion of compound. Since the composition and physico-chemical properties of the compound after irradiation with an electron beam (absorbed dose of 1 MGy) are constant the radiation resistance of compound was established.

• 자원환경지질
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• 제53권2호
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• pp.159-166
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• 2020

본 연구에서는 금정광내 금회수율을 증진하고자 마이크로웨이브 전처리방법을 이용하여 티오요소용출 실험을 수행하였다. 이에 본 연구에서는 먼저 마이크로웨이브를 이용하여 금정광 시료 내 황철석의 분해에 따른 광물상 변화를 관찰하였다. 마이크로웨이브의 조사시간이 증가함에 따라 시료의 온도는 증가하였고, 황철석 내 S가 SO₂로 변환되어 시료 내 S의 함량이 감소되었다. X-선 회절분석 및 주사전자현미경 에너지 분산 분광분석을 통해 황철석은 자류철석과 적철석으로 변환되었으며, 미세균열이 발달된 다공질의 형태로 변질되었음을 확인할 수 있었다. 다양한 조건의 티오요소 혼합 용매를 이용하여 시료의 광물상변화에 따른 금 용출효율을 측정한 결과, 마이크로웨이브 조사시간 증가 및 용출실험 조건 내 용매의 농도 증가에 따라 용출효율이 증가하였다. 결론적으로, 마이크로웨이브를 활용한 금정광 조사는 시료 내 금의 최대용출효율과 용출속도를 증가시켰으며, 티오요소 용매제는 용출속도상수를 증가시켜주는 역할을 하였다.

• Journal of the Korean Wood Science and Technology
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• 제33권3호통권131호
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• pp.53-63
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• 2005

본 연구는 바다목장사업 소재로서 방부처리 목재의 사용 가능성에 대한 기초자료를 얻고자 실시하였다. CCA, CCFZ, ACQ 처리재 내 포함된 유해 중금속의 해수에 대한 용탈 안전성을 평가하기 위해 각각 2% 및 3% 방부제 수용액으로 처리한 목재를 증류수, 자연해수 및 인공적으로 염도를 조절한 인공해수에 41일간 폭로하여 기간 별 각 성분의 용탈량을 측정하였다. 바닷물에서 CCA 처리재의 구리 및 크롬의 용탈은 거의 일어나지 않았으며, 다소 많은 비소의 용탈이 있었으나 증류수에서의 용탈에 비해 적은 양을 나타내었다. CCFZ는 증류수에서 크롬과 아연의 용탈량이 매우 높았으나 바닷물에서는 훨씬 적은 용탈량을 나타내었다. 방부제 흡수량 및 인공해수의 염분 농도에 따른 용탈량에는 큰 차이가 없었다. ACQ 처리재는 CCA 및 CCFZ 처리재에 비해 많은 구리 용탈을 나타내었으며 용탈 매체에 따른 차이는 나타나지 않았다.