• Resources Recycling
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• v.21 no.6
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• pp.58-64
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• 2012

A study on the solvent extraction for the separation and recovery of Ni and Li from the leaching solution of active cathode materials of Li-ion batteries was investigated using PC88A(2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester). The experimental parameters, such as the pH of the solution, concentration of extractant and phase ratio were observed. Experimental results showed that the extraction percent of Ni and Li and separation factor of Ni/Li were increased with increasing the equilibrium pH. More than 99.4% of Ni and 28.7% of Li were extracted in eq. pH 8.5 by 25% PC88A and the separation factor of Ni/Li was 411.6. From the analysis of McCabe-Thiele diagram, 99% of Ni was extracted by three extraction stages at phase ratio(A/O) of 1.5. Stripping of Ni and Li from the loaded organic phases can be accomplished by sulfuric acid as a stripping reagent and 50-60g/L of $H_2SO_4$ was effective for the stripping of Ni.

• Resources Recycling
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• v.16 no.4
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• pp.3-9
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• 2007

Dismantlement of lithium primary batteries without explosion is required to recycle the lithium primary batteries which could be exploded by heating too much or crushing. In the present study, the optimum discharging condition was investigated to dismantle the batteries without explosion. When the batteries were discharged with $0.5kmol{\cdot}m^{-3}$ sulfuric acid, the batteries became inert after 4 days at $35^{\circ}C$ and after 1 day at $50^{\circ}C$, respectively. This result shows that higher temperature accelerates inert of the batteries. Because loss of metals recycled increases when the batteries are discharged only with the sulfuric acid, discharging process using acid solution and water was newly proposed. When the batteries were discharged with water during 24 hours after discharging with $0.5kmol{\cdot}m^{-3}$ sulfuric acid during 6 hours, the batteries discharged were dismantled without explosion. Because decrease in loss of metals was accomplished by new process, the recycling process of the batteries could become economic by the 2-step discharging process.

• Resources Recycling
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• v.28 no.5
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• pp.60-67
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• 2019

A valuable metal recovery from waste resources such as spent rechargeable secondary batteries is of critical issues because of a sharp increase in the amount of waste resources. In this context, it is necessary to research not only recycling waste lithium-ion batteries (LIBs), but also reusing valuable metals (e.g., Li, Co, Ni, Mn etc.) recovered from waste LIBs. In particular, the lithium hydroxide ($LiOH{\cdot}xH_2O$), which is of precursors that can be prepared by the recovery of Li in waste LIBs, can be reused as a catalyst, a carbon dioxide absorbent, and again as a precursor for cathode materials of LIB. However, most studies of recycling the waste LIBs have been focused on the preparation of lithium carbonate with a recovery of Li. Herein, we show the preparation of high purity lithium hydroxide powder along with the precipitation process, and the systematic study to find an optimum condition is also carried out. The lithium carbonate, which is recovered from waste LIBs, was used as starting materials for synthesis of lithium hydroxide. The optimum precipitation conditions for the preparation of LiOH were found as follows: based on stirring, reaction temperature $90^{\circ}C$, reaction time 3 hr, precursor ratio 1:1. To synthesize uniform and high purity lithium hydroxide, 2-step precipitation process was additionally performed, and consequently, high purity $LiOH{\cdot}xH_2O$ powder was obtained.

• Korean Journal of Psychosomatic Medicine
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• v.12 no.2
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• pp.145-156
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• 2004

Objectives : Internet addiction is a newly appeared addictive phenomenon that is defined as 'difficulty in real life due to internet over-use', 'excessive time spent on the internet or replacement of genuine real relationships with superficial virtual ones' or 'weakness in self-control about internet use and if discontinued, fallen in psychological confusion and anergic state'. This study was aimed to compare the internet addiction rate, demographic factors, computer using patterns, anxiety, depression, and internet self-efficacy and outcome expectancy between Korean middle and high school students in three areas - Seoul, Cheonan, and Rural areas - that were different in economic, cultural, and geographic state. Methods : Subjects are consisted of middle and high school students in Seoul, Chunan, and Rural areas(N=1718). Self-rating questionnaire included demographic data, Korean Spielberger State-Trait Anxiety Inventory, Korean Self-Rating Depression Scale(SDS), questions for internet-using pattern, Korean version of Internet Addiction Scale invented by K. S. Young, Internet Self-efficacy and Out-come Expectancy Scale. Results: In this study, prevalence of internet addiction was 2.9%. There was no significant difference found in prevalence of internet addiction among three areas. In all subjects, there were significant differences in anxiety, depression, internet self-efficacy and outcome expectancy, leisure style, places of internet use, internet connecting method, and insight on internee addiction. But, in addicted group, there was no significant difference among three areas. Conclusion: This study suggested that the difference in economic, cultural, and geographic state was not related to prevalence of internet addiction. Although there were significant differences in anxiety, depression, self-efficacy associated with internee use, leisure style, places of internet use, internet connecting method, insight on internet addiction among three areas, there were no significant difference in addicted group among three areas. So, we concluded that the difference in economic, cultural, and geographic state did not influence the prevalence of internet addiction, and despite the difference in economic, cultural, and geographic state, people in three areas were equally influenced by internet addiction.