• Journal of the Korean GEO-environmental Society
• /
• v.18 no.12
• /
• pp.25-36
• /
• 2017

This research was conducted to investigate the removal characteristics of heavy metals and sulfate ion from acid mine drainage (AMD) by multi-functional zeolite-slag ceramics (ZS ceramics), in which natural zeolite and converter slag were mixed and calcined at high temperature. The batch test showed that the removal efficiency of heavy metals by pellet-type ZS ceramics increased as the mixing weight ratio of converter slag to natural zeolite increased. The optimal mixing ratio of natural zeolite to converter slag for the removal of heavy metals and sulfate ion from AMD was observed to be 1:2~1:3. The adequate calcination temperature and time of ZS ceramics for the treatment of AMD were found to be $600{\sim}800^{\circ}C$ and 2 hours, respectively. The removal test of heavy metals and sulfate ion from AMD by the ZS ceramics prepared in optimal condition exhibited very high removal efficiencies close to 100% for all heavy metals (Al, As, Cd, Cu, Fe, Mn, Pb, Zn) and 77.1% for sulfate ion. The experimental results in this study revealed that the ZS ceramics could function as an effective agent for the treatment of AMD.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.4 no.2
• /
• pp.149-156
• /
• 2016

It has been well known that concrete structures exposed to chloride and sulfate attack environments lead to significant deterioration in their durability due to chloride ion and sulfate ion attack. The purpose of this experimental research is to evaluate the long-term durability against chloride ion and sulfate attack of the alkali activated cementless concrete replacing the cement with ground granulated blast furnace slag. For this purpose, the cementless concrete specimens were made for water-binder ratios of 40%, 45%, and 50%, respectively and then this specimens were cured in the water of $20{\pm}3^{\circ}C$ and immersed in fresh water, 10% sodium sulfate solution for 28, 91, 182, and 365 days, respectively. To evaluate the long-term durability to chloride ion and sulfate attack for the cementless concrete specimens, the diffusion coefficient for chloride ion and compressive strength ratio, mass change ratio, and length change ratio were measured according to the NT BUILD 492 and JSTM C 7401, respectively. It was observed from the test results that the resistance against chloride ion and sulfate attack of the cemetntless concrete were comparatively largely increased than those of OPC concrete irrespective of water-binder ratio.

• Journal of the Korean Chemical Society
• /
• v.30 no.5
• /
• pp.409-414
• /
• 1986

The reduction of $VO_2^+$ ion by ethanol in sulfuric acid leads to the formation of vanadyl sulfate. Spectrophotometric measurements on the solution containing products, vanadyl sulfate, are also reported. Kinetic studies on reduction of $VO_2^+$ by ethanol have been carried out at 35${\circ}C$ and 50${\circ}C$. The reaction mechanism for reduction of $VO_2^+$ is discussed.

• Journal of the Korean institute of surface engineering
• /
• v.16 no.4
• /
• pp.160-172
• /
• 1983

티오요소류, 폴리에테르류, 염료와 같은 유기화합물이 첨가된 황산동 전기도금욕에서 석출된 구리의 광택, 평활력효과를 무첨가욕과 기존 광택제가 첨가된 도금욕에서와 각각 비교하여 이들 유기첨가제가 구리의 석출상태와 음극분극에 미치는 영향을 Hull cell 실험과 현미경관찰, 전기화학적 측정방법에 의해 고찰하였다. 황산동 전기도금욕에서 thiourea, 2-mercapto-2-imidazoline, 1-acetyl-2-thiourea와 같은 유기 황화합물은 비교적 고전류 밀도 범위에서 결정성장이 억제되고 입자가 미세한 구리석출을 일으켜 양호한 광택효과와 평활력을 가져오나, 특히 저전류밀도에서는 해로운 줄무늬가 발생한다는 점에서 많은 개선의 여지가 필요하다. 그러나 이들 유기 황화합물에 1,3-dioxolane polymer와 소량의 염소 이온을 혼합 첨가할 것 같으며 넓은 전류밀도 범위에서 양호한 광택과 평활력이 있는 동석출을 얻을 수 있었다.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 1999.10a
• /
• pp.438-439
• /
• 1999

남극은 인위적인 오염원에서 멀리 떨어져 있고 가장 깨끗한 환경을 유지하고 있기 때문에 배경환경으로써 평가되어져 왔다. 따라서 ice core 안에서, 시간에 따른 용해성 이온종들의 조성 변화는 지구 대기조성 변화를 나타내는 것으로 알려져있다. 특히 ice cores나 눈 속에 존재하는 황산염과 MSA(Methan Sulfonic Acid)는 해양생물의 활동도 변화론 연구하는데 있어 유용한 도구를 제공해주며, 그것은 과거 기상적 변화와 관련이 있다.(중략)

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.1 no.2
• /
• pp.136-143
• /
• 2013

In the sewage structures and wastewater facilities, concrete is exposed to hydrogen sulfide ($H_2S$) which acts as an acid material in a solution, and a strongly acidic sulfate ion ($SO{_4}^{-2}$) is generated by a sulfuric bacteria. Hence, a degradation of concrete with biochemical corrosion would be accelerated. Finally, durability of concrete and concrete structures may be greatly reduced. In this study, in order to remove the hydrogen sulfide which is used by the sulfuric bacteria organic-biologically, the antibiotic metal and metallic salt powders were mixed to concrete, and a suppressing performance of the sulfate ion was assessed. For the sulfuric acid bacteria, a comparative evaluation of antimicrobial performance on neutralized concrete specimens were carried out, also by a rapid chloride penetration test, chloride penetration depths and diffusion coefficients were measured for antibiotic concrete in accordance with the amount of metal and metallic salt-based antibacterial agents. Eventually, by an observation of the biochemical state of the surface of concrete specimens exposed outdoors, the performance and applicability of antibiotic concrete were confirmed.

• Resources Recycling
• /
• v.14 no.6 s.68
• /
• pp.28-36
• /
• 2005

A hydrometallurgical process to leach cobalt from the waste cathodic active material, $LiCoO_{2}$, and subsequently to separate it by solvent extraction was developed. The optimum leaching conditions for high recovery of colbalt and lithium were obtained: 2.0 M sulfuric acid, 5 $vol.\%$ hydrogen peroxide, $75^{\circ}C$ leaching temperature, 30 minutes leaching time and an initial pulp density of 100 g/L. The respective leaching efficiencies for Co and Li were $93\%$ and $94.5\%$. About $85\%$ Co was extracted from the sulfuric acid leach liquor containing 44.72 g/L Co and 5.43 g/L Li, using 1.5 M Cyanex272 as an extractant at the initial pH 5.0 and in organic to aqueous phase ratio of 1.6:1 under the single stage extraction conditions. The Co in the raraffinate was completely extracted by 0.5 M Na-Cyanex272 at the inital pH 5.0, and an organic to aqueous phase ratio of 1;1. The cobalt sulfate solution of higher than $99.99\%$ purity could be recovered from waste $LiCoO_{2}$, using a series of hydrometallurgical processes: sulfuric acid leaching of waste $LiCoO_{2}$- solvent extraction of Co by Na-Cyanex 271 - scrubbing of Li by sodium carbonate solution - stripping of Co by sulfuric acid solution.

• Resources Recycling
• /
• v.32 no.1
• /
• pp.13-20
• /
• 2023

The objective of this article is to summarize the commercial lithium ion battery (LIB) recycling processes in Korea and to suggest new direction for LIB recycling. A representative LIB recycler, SungEel Hitech Co. has successfully operated the LIB recycling process for over 10 years, and new recycling processes were recently proposed or developed by many recycling companies and battery manufacturers. In the new recycling processes, lithium is recovered before nickel and cobalt due to the rapid rise in lithium prices, and metal sulfate solution as final product of recycling process can be supplied to manufacturers. The main problem that the new recycling process will face is impurities, which will mainly come from end-of-life electric vehicles or new additives in LIB, although the conventional processes must be improved for mass processing.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1997.05b
• /
• pp.313-318
• /
• 1997

방사성 금속폐기물을 재활용하기 위한 제염기술로서 SC ( Sulfuric acid - Cerium) 제염의 기본특성을 파악하기 위해 Ce$^{4+}$ Ce$^{3+}$ 이온쌍의 산화환원 특성을 cyclic voltammetry 방법으로 연구하였다. 황산용액 내에서 Ce$^{4+}$ Ce$^{3+}$ 이온쌍의 산화환원 특성 조사를 위해서는 백금전극이 효과적이었다. 이중 실린더형 전해셀의 백금전극에서 Ce$^{4+}$ Ce$^{3+}$ 이온쌍의 산화환원에 대한 전달계수, 확산계수 및 비균일 속도상수 둥을 구하였으며, 각각 0,63 $\pm$ 0.05, (2.09$\pm$0.49) x $10^{-5}$ $\textrm{cm}^2$/sec 및 (2.53 $\pm$ 1.33) * $10^{-4}$ cm/sec 의 값을 나타내었다.

• Analytical Science and Technology
• /
• v.16 no.2
• /
• pp.159-165
• /
• 2003

To develop an ionic equilibria model applicable to the sulfuric acid leaching solutions of zinc oxide ore, the method of the Pitzer equation and that of the Vasil'ev equation were compared. As the ionic strength of the solution increased to 9 m, the results of ionic equilibria by the Pitzer equation were more accurate than those by Vasil'ev. To simulate the sulfuric acid leaching solutions of zinc oxide ore, the mixed solutions with the various composition of $ZnSO_4-Fe_2(SO_4)_3-Na_2SO_4-H_2SO_4-NaOH-H_2O$ were prepared. The pH values calculated in this study agreed well with those measured at $25^{\circ}C$.