• Transactions of the Korean hydrogen and new energy society
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• v.32 no.6
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• pp.612-617
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• 2021

In the case of a metal sulfide electrode, it is used as an anode or cathode active material in a lithium battery. The reason is that the voltage exists between 0.8 and 2.0 V via lithium electrode and the discharge and charge capacity is high. In order to manufacture nickel sulfide for electrode, which are widely used, nano-nickel powder was sulfided using ammonium polysulfide, and single-phase NiS electrodes were manufactured through heat treatment. The prepared NiS electrode had a high initial capacity of 500 mAh/g or more, and was stabilized after 20 cycles to maintain a capacity of 400 mAh/g or more until 100 cycles.

• Journal of Energy Engineering
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• v.10 no.2
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• pp.132-139
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• 2001

석탄가스화 복합발전의 집진 공정에 사용하기 위한 금속제 safety filter의 재질 선정을 위하여 황화수소 가스 분위기에서 합금강의 부식 특성을 규명하였다. 사용 합금강은 SUS 310, SUS 316, Inconel 600과 Hastelloy X이다. 전기로 내에 설치된 지름 50mm의 qualtz 튜브 반응기에서 부식실험이 행하여졌다. 40$0^{\circ}C$부터 $700^{\circ}C$까지의 등은 조건에서 실험이 행하여졌고, 분위기 가스의 영향을 보기 위하여 H$_2$S 가스를 함유한 $N_2$(dry), $N_2$(saturation), $CO_2$(dry), 그리고 석탄가스 분위기에서 실험하였다. 부식 생성물을 파악하기 위하여 X-ray 회절기와 주사전자현미경 분석이 함께 이루어졌다. 1.7% H$_2$S, $600^{\circ}C$ 이하 온도 조건에서는 니켈계 내식강 중 Hastelloy X와 철계 내식강 중 SUS 310 등 고크롬 합금강이 IGCC 용 필터 소재 금속으로서 높은 내부식성을 나타내었다. 0.3%~4.99% 황화수소 농도 범위에서 황화수소 농도 변화에 따라서 SUS 310의 경우 3~237mg/d$m^2$.day, Inconel 600의 경우 4~660mg/d$m^2$.day로 부식속도는 크게 증가되었다. 50$0^{\circ}C$, 석탄가스 분위기에서 부식속도는 SUS 310은 45mg/d$m^2$.day, SUS 316은 110mg/d$m^2$.day, Inconel 600은 576mg/d$m^2$.day, 그리고 Hastelloy X 는 140mg/d$m^2$.day로서 합금강 시편 중 SUS 310 합금강이 가장 우수한 내식성을 나타내었다. 부식 표면에는 황화니켈, 황화철 피막이 형성되었다.

• The Safety technology
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• no.103
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• pp.68-71
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• 2006

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.913-924
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• 1996

In this study HDS(hydrodesulfurization) of thiophene was researched over nickel catalysts added with small amounts of neodymium which were prepared by different methods such as unsupported coprepricipitated NdNi catalysts, unsupported intermetallic $NdNi_5$ catalysts, and carbon supported NdNi catalyst. The HDS activity was remarkably increased when a small amounts of neodymium was added to unsupported coprecipitated Ni catalysts. Thus it was known that the role of Nd is important in HDS of thiophene of Ni catalysts. For the case of unsupported intermetallic $NdNi_5$, the intermetallic crystallinity was destroyed to oxide and sulfide after calcination and presulfidation respectively. The HDS activity of thiophene can be explained by surface area of unsupported catalysts. And Nd acts like as structural promoter keeping the high surface area of unsupported catalysts. The HDS activity was increased by each ten times based on 1 gr. of nickel in the order of unsupported intermetallic $NdNi_5$, unsupported coprecipitated NdNi, and carbon supported NdNi catalysts according to different preparation method of catalysts.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.1
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• pp.138-143
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• 2020

Metal sulfides are good candidates for cathode materials. Especially, iron sulfides and nickel sulfides have been demonstrated to be potential electrode materials among metal sulfides due to nontoxicity and high theoretical specific capacities. Electrochemical properties (capacity, cycle life, stability etc.) of Li/iron sulfides or nickel sulfides cell were improved by methode such as coating, doping of material, and nanoization of materials etc.

• Resources Recycling
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• v.22 no.6
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• pp.48-54
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• 2013

The methods to separate and remove copper in the mixed solution ((399 ppm Cu, 208 ppm Fe, 15.3 g/L Ni, 2.1 g/L Co) with nickel, cobalt and iron were investigated. With hydroxide precipitation method, copper and iron ions were completely precipitated and removed from the solution at pH 7 while some nickel and cobalt also were precipitated. 99.75% copper could be precipitated and removed as copper sulfide from the solution with adding $Na_2S$ (1.25 w/v concentration) of 2 times equivalent of Cu at pH 1. Copper was selectively absorbed on TP 207 ion exchange resin at equilibrium pH 2.0 and could be eluted from copper-loaded resin using 5% $H_2SO_4$.

• Resources Recycling
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• v.28 no.5
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• pp.51-59
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• 2019

This study focused on the synthesis of the nickel hydroxide using ammonium sulfate in leaching solution from waste nickel-cadmium batteries. The effect of pH, temperature and the input amount of ammonium sulfate in leaching solution was investigated. The ammonium nickel sulfate with high purity was obtained in acidic leaching solution and the solution temperature of $60^{\circ}C$. The suitable molar ratio of the input amount of ammonium sulfate to nickel in solution is 2:1. The impurity about 1.4 at.% of Cd was included in the nickel hydroxide precipitates when ammonium nickel sulfate was used. At the process using sodium sulfide which precipitates the cadmium in solution, nickel and iron compounds were precipitated together.

• Resources Recycling
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• v.27 no.4
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• pp.36-43
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• 2018

In order to recycle waste nickel-cadmium batteries, cadmium was selectively removed by ion substitution reaction so that cadmium and nickel could be separated efficiently. The electrode powder obtained by crushing the electrode in the waste nickelcadmium battery was leached with sulfuric acid. The cadmium in the nickel-cadmium solution was precipitated with cadmium sulfide by the addition of sodium sulfide. Ion substitution experiments were carried out under various conditions. At the optimum condition with pH = -0.1 and $Na_2S/Cd=2.3$ at room temperature, the residual Cd in the solution was about 100 ppm, and most of it was precipitated with CdS.

• Resources Recycling
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• v.14 no.6 s.68
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• pp.16-20
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• 2005

The selective sulphide precipitation of copper from sulphate solution containing nickel and cobalt was studied with adding $Na_{2}S$ solution. Precipitation efficiency of copper increased with raising pH of solution and increasing the amount of $Na_{2}S$ added and lowing its concentration. The increase in reaction time and temperature also improved the precipitation of copper. However, attempts to selectively precipitate copper met with limited success because of co-precipitation of nickel and cobalt. With adding $20\%$ $Na_{2}S$, 3 times equivalent of Cu, at pH 1.0 of solution, $25^{\circ}C$ and 30 minutes of reaction time, precipitation efficiencies of copper, nickel and cobalt were $94.1\%$, $4.3\%$ and $4.5\%$ respectively.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.4
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• pp.323-336
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• 2023

We investigated the nickel potential and genesis of ultramafic rocks in the Yugu area to secure nickel resources in South Korea. The Yugu ultramafic rocks, located in the southwest of the Gyeonggi Massif, are characterized by spinel peridotite and exhibit strong serpentinization along their boundaries. The serpentinization is observed as olivine transformed to antigorite and chrysotile, while pentlandite, the nickel sulfide mineral, altered into millerite and awaruite. Serpentine displays distinct foliation, aligning subparallel to the ultramafic rock boundaries and foliation of Yugu gneiss. This suggests that the uplift of ultramafic rocks resulted in hydrothermal infiltration likely sourced from the Yugu gneiss metamorphism. The Yugu ultramafic rocks are residues after 5~18% partial melting of abyssal peridotite. Enriched light rare earth elements and Eu imply secondary metasomatism. Geochemistry suggests a link between the formation of Yugu ultramafic rock and the Triassic collision of the North and South China continents. The nickel content is around 0.17~0.21%, mainly contained in olivine and serpentine. Hence, in addition to the mineral processing study on the sulfide minerals, focused studies on oxide minerals for enhanced nickel recovery within the Yugu ultramafic rock are strongly suggested.