Comparison between the effect of microwave irradiation and conventional heat treatments on the magnetic properties of chalcopyrite and pyrite

Elmahdy, Ahmed M.; Farahat, Mohsen; Hirajima, Tsuyoshi

doi:10.1016/j.apt.2016.08.020

Cited by 21 publications

(16 citation statements)

References 19 publications

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“…The CuSO4 at 934.7 eV is caused by surface oxidation of CuS. 34 Here, the presence of CuS in the starting cathode in additionally confirmed by the satellite peaks. After cycling, however, only Cu0 is detected.…”

Section: Resultssupporting

confidence: 61%

Investigation of the Effects of Copper Nanoparticles on Magnesium-Sulfur Battery Performance: How Practical Is Metallic Copper Addition?

Ford

Merrill

et al. 2019

Preprint

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Rechargeable magnesium sulfur (Mg/S) batteries suffer from fast capacity fading due to difficulty of reoxidation of MgS and the polysulfide shuttle. Other works have reported that use of Cu current collectors or CuS at the cathode improves cycleability. Here we investigate Cu nanoparticles grown on carbon nanofibers (Cu@CNF) as an additive for the Mg/S battery cathode to test the effects of Cu metal on capacity and rate performance at controlled Cu loading. The Mg/S battery with Cu additives can run at 1 C with a capacity of 452 mAh/g after 100 cycles. It was confirmed via X-ray photoelectron spectroscopy that Cu<sub>2</sub>S forms during cathode formation and contributes to the high initial capacity, but then converts back to metallic Cu. Upon extending cycling, the Cu additives promote the formation of smaller, more dispersed discharge product particles, thereby enhancing reversibility. Finally, it is found that the loading of S and Cu at the cathode must be low to achieve substantial and sustained benefits of the Cu additives.

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Section: Resultssupporting

confidence: 61%

Investigation of the Effects of Copper Nanoparticles on Magnesium-Sulfur Battery Performance: How Practical Is Metallic Copper Addition?

Ford

Merrill

et al. 2019

Preprint

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“…Thus, its temperature is lower than chalcopyrite (McGill et al, 1988) while being subjected to a constant period of exposure time. This is a possible reason causing a reduction on oxide species on pyrite's surface compared to that on chalcopyrite (Elmahdy et al, 2016). This can be explicitly seen for all three samples by consideration of oxygen component for chalcopyrite and pyrite resulting in intensive oxidation of chalcopyrite's surface than pyrite's one.…”

Section: Scanning Electron Microscopy (Sem) Studiesmentioning

confidence: 81%

“…6). In addition to increasing the oxygen, reduction of surface sulfur leads to the formation of sulfate (SO 7 83 ) on the mineral's surface (Elmahdy et al, 2016). Klauber et al, 2008 believes that at this stage, the surface sulphur layer formed are crustily and as shown in Fig.…”

Section: Metallurgical Evaluationmentioning

confidence: 99%

“…7d, porous layers have been created on the mineral surface. The amount of iron had been decreased in all three stages of pretreatment at the surface of two minerals that indicating the formation of moderate oxide layers (ferric sulfate (Fe2(SO4)3)) (Elmahdy et al, 2016). Increasing the power level of the microwave leads to an intense oxidation and creates magnetic phases such as Goethite (FeOOH) and Hematite (Fe2O3) on the mineral surface.…”

Section: Metallurgical Evaluationmentioning

confidence: 99%

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Effect of microwave system location on floatability of chalcopyrite and pyrite in a copper ore processing circuit

Gholami¹,

Rezai²,

Mehdilo³

et al. 2020

Physicochem. Probl. Miner. Process.

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The present work aims at investigating the effect of microwave local positions (i.e. before crushing (BC), after crushing (AC) and after milling (AM)) on microwave-assisted flotation of chalcopyrite and pyrite in a porphyry copper complex deposit. Individual given samples for each state were pre-treated with a variable power microwave at a power level of 90 to 900W for 15, 30, and 60s. Furthermore, froth floatation experiments were carried out using a laboratory mechanical Denver flotation cell on both microwave-treated and untreated samples. Particle surface properties were characterized by a scanning electron microscopy (SEM) and an energy-dispersive X-ray spectroscopy (EDX) analysis. The results showed that the chalcopyrite and pyrite floatabilities increased monotonically by rising the exposure time and power level for the uncrushed preconditioned samples (BC) due to the enhancement of mineral liberation degrees together with the formation of sulphide species and polysulphides on the mineral surfaces. However, flotation results of treated samples for the crushed one (AC) revealed an optimum range. Formation of intensive oxide layers on the mineral surfaces of milled samples (AM) led to a substantial reduction in their recoveries by increasing the microwave's power level and the sample's exposure time. The results obtained from mineral's floatabilities in recleaner stage showed that the microwave-assisted sample at 900W for 30s at BC state favourably provided 5% higher S.E.'s than that of the untreated sample. Finally, it was concluded that the microwave pretreatment of samples induced the best floatability responses if it located before the crusher.

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“…질산 용매와 공기가 접촉하는 경계면(interface) 즉, 수면층이 제 일 먼저 비등(boiling)하면서 동시에 기포가 발생한 다 (Fig. 5b) (Haque, 1999;Huang and Rowson, 2002;Batchelor et al, 2015;Elmahdy et al, 2016). 마이크로웨이브-침출실험을 시간별로 수행하였고 그 고체-잔류물에 대하여 왕수분해하여 As 및 Bi 함 량을 측정하였다.…”

Section: 결과 및 고찰unclassified

A Study on the Removal of Penalty Elements and the Improvement of Gold Contents from Gold Concentrate Using Microwave-nitric Acid Leaching

Kim¹,

Purev²,

Park³

2019

J. Miner. Soc. Korea

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요약 : 본 연구는 금 정광에 함유된 비소(As) 및 비스무스(Bi)와 같은 페널티 원소(penalty elements)를 제 거하기 위한 목적으로 마이크로웨이브-질산침출을 이용하였다. 또한, 금 정광 시료로부터 금 함량을 증가시키고자 하였다. 침출조건은 페널티 원소의 제거를 향상시키기 위해 질산농도, 침출시간 그리고 고액비를 변화하였다. 실험결과 고체-잔류물에서 시료무게 감소율, 비소와 비스무스의 제거율 그리고 금 함량은 질산농도와 침출시간이 증가할수록 그리고 고액비가 감소할수록 증가하였다. 최대 비소와 비스무스 제거율 및 금 함량이 얻어지는 침출조건은 질산용액의 농도 6 M, 침출시간 5분이었다. 이 때, 고체-잔류물 시료의 무게 감소는 87 %, 비소 제거율은 98.23 %, 비스무스는 거의 제거(100 %)되었 고 금 함량은 81.36 g/t에서 487.32 g/t으로 증가하였다. 고체-잔류물을 XRD로 분석한 결과, 질산농도 가 증가할수록 황철석 피크들은 사라지고 반면에, 원소 황의 피크들이 증가하였다.주요어 : 페널티 원소, 마이크로웨이브-질산침출, 비소, 비스무스, 금 ABSTRACT : This study used microwave-nitric acid leaching with the aim of removing penalty elements such as As and Bi. Moreover, enhanced gold content from the gold concentrate sample. The leaching conditions were changed: leaching time, nitric acid concentrations and solid-liquid ratio; In order to improve the removal of penalty elements. As a result of the experiment; sample weight loss rate, As and Bi removal rate and gold content in the solid-residues have been increased when the nitric acid concentration and leaching time were increased while the solid-liquid ratio was decreased. The leaching conditions for the maximum As and Bi removal and gold content were: leaching with a 6.0 M nitric acid solution doing 5 min. At these, the solid-residue sample weight loss was 87 %. As removal rate was 98.23 % and Bi was completely removed (100 %). Furthermore, gold content increased from 81.36 g/t to 487.32 g/t. The XRD of the solid residue showed that pyrite disappeared as the nitric acid concentration was increased, whereas sulfur peaks was increased, too.

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Comparison between the effect of microwave irradiation and conventional heat treatments on the magnetic properties of chalcopyrite and pyrite

Cited by 21 publications

References 19 publications

Investigation of the Effects of Copper Nanoparticles on Magnesium-Sulfur Battery Performance: How Practical Is Metallic Copper Addition?

Investigation of the Effects of Copper Nanoparticles on Magnesium-Sulfur Battery Performance: How Practical Is Metallic Copper Addition?

Effect of microwave system location on floatability of chalcopyrite and pyrite in a copper ore processing circuit

A Study on the Removal of Penalty Elements and the Improvement of Gold Contents from Gold Concentrate Using Microwave-nitric Acid Leaching

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