• Resources Recycling
• /
• v.18 no.5
• /
• pp.44-51
• /
• 2009

Fundamental study has been made on the recovery of copper from the electronic scrap by hydrometallurgical process. Nitric acid was used as a leaching agent to dissolve the metals such as Cu, Sn, Pb, Fe etc. from the crushed electronic scraps. TBP was employed to extract nitric acid from the strong nitric acid leaching solutions and to reclaim nitric acid. From the experimental results, Cu was effectively leached by 3.0-4.0 M nitric acid. And 95% of nitric acid in the leaching solution was extracted by 60% TBP, and 98% of nitric acid was stripped from the loaded organic phase by distilled water and it was possible to reuse as a leaching agent.

• Resources Recycling
• /
• v.1 no.1
• /
• pp.51-57
• /
• 1992

The hydrochloric acid leaching has been studied as a fundamental experiment on the recovery of arsenic from arsenic-bearing copper slime in copper electrorefining. The slime is mainly composed of $\beta-Cu_3As$ Which is intermetallic compound of CU and As. And the minor components are $CU_2O$ and CusAs in the slime. The optimum conditions of leaching of the slime were found to be as follows : 6N hydrochloric acid, particle size passed through 140 mesh, leaching for 150 min at $60^{\circ}C$, ratio of HCI/slime of 3 to 1 ; where 98 percent of arsenic were leached out of the As-bearing slime.

• Resources Recycling
• /
• v.14 no.5 s.67
• /
• pp.45-53
• /
• 2005

Electro-generated chlorine leaching of waste printed circuit boards was investigated in hydrochloric acid solutions. Non-magnetic component of $0.6{\sim}1.2mm$ was prepared by grinding, magnetic separation, and sieving. The non-magnetic component of pulverized printed circuit board contained about 45% of metal component, in which copper was about 83.6%. The leaching rate of copper was greatly affected by current density and agitation speed. The leaching of copper up to 98% was achieved at $20mA/cm^2$, $50^{\circ}C$, 180 minutes, and 600 rpm in 1M HCl solutions. Increasing agitation and lowering current density enhanced utilization efficiency of electro-generated chlorine. Leaching of copper was suppressed at the initial stage, while the minor metal elements, such as aluminum, lead, and tin, were dominantly leached out.

• Resources Recycling
• /
• v.24 no.3
• /
• pp.3-10
• /
• 2015

A study has been made on the recovery & separation of cobalt and copper from organic acid leaching solution by solvent extraction. The experimental parameters such as the equilibrium pH, concentration of extractant and phase ratio were observed. Copper was extracted using LIX 84 and Cobalt was extracted using cyanex 272 and versatic acid 10. Experimental results showed that extraction percent of copper was 99% at above eq. pH 2.0 and then more than 90% of cobalt were extracted by cyanex 272 in eq. pH 6.0 and versatic acid 10 in eq. pH 7.5. Stripping of copper and cobalt from the loaded organic phases can be accomplished by sulfuric acid as a stripping reagent and 120 ~ 150 g/L of $H_2SO_4$ was effective for the stripping of copper and cobalt respectively. Finially, the basic optimal process for recovery of copper and cobalt from the bio-leaching solution was proposed.

• Journal of the Korean Wood Science and Technology
• /
• v.31 no.4
• /
• pp.38-43
• /
• 2003

This is the second in a series of reports on the evaluation of weathering durability of waterborne preservative treated wood by accelerated weathering. The leaching of copper from ACQ-, CCA-, and CuAz-treated samples during weathering was increased by UV irradiation, when compared between full weathering and water-only weathering. The FTIR spectra of the weathered ACQ-, CCA, CuAz-treated samples at 1731 cm^-1, 1625 cm^-1, 1510 cm^-1, which are related to the fixation of copper, were different from those of unweathered controls. This result means that UV irradiation can weaken the chemical bond between lignin and copper and/or extraction of lignin-copper complex can be occured when lignin erode away by weathering.

• Journal of the Korean Wood Science and Technology
• /
• v.40 no.3
• /
• pp.212-227
• /
• 2012

Current research trends in wood preservatives for enhancing durability was reviewed. Due to leaching of recent Copper-Based Preservatives commonly used as chemicals for pressure treatment; they have been a growing concern, especially in improving the fixation of the copper as alkyl ammonium quat. and azol in wood and preventing the leaching of active ingredients. With the appearance of emulsion type chemicals using micronized and nano-sized wood preservatives, researchs on characteristics of Copper-Based Preservatives regarding penetration and fixation in wood are debatable. Moreover, unlike the case of CCA, the recent alkyl ammonium quat. and azol bear a serious threat in the decrease of antimicrobial effectiveness against wood destroying fungi with copper tolerance. Therefore, development and research of co-biocide is needed.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.11a
• /
• pp.447-454
• /
• 2000

This paper presents fundamental characteristics of a copper slag when used geotechnical materials. For this study, it was conducted laboratory tests such as compaction, large direct shear, hydraulic conductivity, leaching, TDR, frost heave test and so on. The results of laboratory tests shown gradually increase in draining capacity and shearing resistance more slag mixing. The unfrozen water in temperature changes and frost heave amounts in condition of -17 $^{\circ}C$ appeared to decrease. Also, toxicity tests based on the domestic solid waste regulations were satisfied with nonhazardous. By this research results, a copper slag mixed with granite soil may been used as granular base and embankment materials, fill etc.

• Journal of the Mineralogical Society of Korea
• /
• v.28 no.1
• /
• pp.17-28
• /
• 2015

In order to study the mineralogical and chemical characteristics of copper slag, optical microscopy, SEM/EDS, EPMA, AAS and XRD analyses were carried out. In addition, sulfuric acid leaching experiments were performed to investigate the potential of the slag as a copper resource. It was confirmed that fayalite, chromite, bornite and chalcopyrite were contained in the slag. The slag mainly consisted of acicular fayalite and skeletal lath -euhedral chromite crystals. Also a very large amount of bornite and chalcopyrite grains were contained in the slag. The content of Fe and Cu in the slag was 18.37% and 0.93%, respectively. As a result of sulfuric acid leaching experiments, the leaching rates of Cu and Fe were increased through decreasing the slag particle size, increasing the sulfuric acid concentration and the leaching temperature. The maximum efficiency of Cu and Fe leaching were obtained under the conditions of particle size of 32 mesh, sulfuric acid concentration of 2.0 M, and leaching temperature of $60^{\circ}C$. Accordingly, it is expected that the slag could be available as a potential and alternative resource of metallic copper.

• Journal of the Korean Wood Science and Technology
• /
• v.33 no.6 s.134
• /
• pp.87-94
• /
• 2005

This study was carried out to investigate the effect of soil types and soil properties on wood preservative leaching. Radiata pine (Pinus radiata Don.) sapwood stakes, which had been treated with 2.0%(w/v) CCA, were leached for 12 weeks by a common laboratory method in four different soils and for 14 days by the AWPA standard leaching method in water. The physical and chemical properties of the four soils were determined, and the percent leaching of the individual component of CCA was correlated with the various soil properties. The data show that leaching of preservative chemicals from treated wood exposed to soil is influenced by the type of soil. The preservative leaching was greater when wood was exposed to water than when the wood was in contact with water-saturated soil. The greatest chromium, copper and arsenic leaching from CCA-treated stakes were observed in the sandy loam, loam, and sand, respectively, and the least amount of leaching of CCA components occurred in the silty loam. The leaching of preservative components from treated wood is extremely complex and appears to be influenced differently by the soil properties. The extent of copper leaching from CCA treated wood appears to be related to exchangeable Mg and sum of bases. There is a reasonably good relationship between chromium leaching and exchangeable Mg, and between arsenic leaching and exchangeable K, soil Ni, Mn, Fe, Cr, or Cu content. Since this study was conducted based on laboratory leaching method using small cross-sectional dimensions; thus, data obtained from this experiment should not be used to predict leaching characteristics from commercial-size wood used in real situation. Accordingly, further studies are necessary using outdoor ground-contact leaching.

• Resources Recycling
• /
• v.16 no.3 s.77
• /
• pp.44-49
• /
• 2007

In the present work, the high temperature oxygen pressure leaching behavior of chalcopyrite was studied in sulfuric acid solution. The influence of leaching time, temperature and oxygen partial pressure on leaching process were examined. Leaching rate of copper increased significantly with increasing leaching temperature. Copper recovery reached 87.1% within 2 hours at $200^{\circ}C$ and 10 atm oxygen pressure, while most of the solubilized iron readily re-precipitates as hematite($Fe_2O_3$). It was confirmed that e main leach reaction of chalcopyrite occurred through oxidation with oxygen under oxygen pressure and high temperature(above $150^{\circ}C$). Because sulfur was oxidized entirely to sulfate, passivating elemental sulfur layer was not formed.