• Resources Recycling
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• v.25 no.1
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• pp.60-67
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• 2016

A scale-up test with a continuous solvent extraction and electro-winning system was carried out to separate and recover copper from a synthetic sulfuric acid solution (Cu 10.5 g/L, Co 2.0 g/L, Ni 15.0 g/L, Fe 0.2 g/L). The solution was introduced into mixer-settlers with four stages of extraction and two stages of stripping for continuous countercurrent solvent extraction to separate copper from nickel and cobalt. The loading was carried out using 40% LIX 84-I(v/v) as extractant with a phase ratio of A : O = 1 : 1. Meanwhile, the stripping was undertaken at a phase ratio of A : O = 1 : 1.5 using depleted electrolyte containing 35.0 g/L Cu and 180 g/L $H_2SO_4$ as stripping solution. The extraction and stripping efficiencies were found to be 96.7% and 91.0%, respectively. The copper composition of the stripped solution (pregnant electrolyte) was 50.0 g/L Cu with impurities of 25 ppm nickel, 5 ppm cobalt and 3 ppm iron. In the electro-winning process, copper metal of 99.833 purity was yielded with current efficiency of 98.9% and current density of $1.50A/dm^2$.

• Bangmulgwan gwa yeongu (The National Museum of Korea Journal)
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• v.1
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• pp.74-95
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• 2024

A vast body of inscribed bricks has been found connected to the mid-fourth-century Tomb of Jang Mui in Bongsan-gun, Hwanghae-do Province. After several inspections of the bricks conducted at the National Museum of Korea in 2023, these inscribed bricks were grouped into ten types. This paper interprets in detail the phrases written on these bricks from the Tomb of Jang Mui in an attempt to understand their characteristics and intentions. This detailed interpretation facilitates a rough understanding of how each phrase relates to the others and in what order the phrases would make full sentences. In terms of their contents, these inscribed bricks are presumed to have been produced to convey information about the construction of the tomb to viewers on the outside. In particular, they relate that a narrator referred to as a Jubu official named Jo was involved in the construction of the Tomb of Jang Mui. They can be compared to the inscribed bricks created in China during the Western Jin and Eastern Jin Dynasties that were produced not by family members of the tomb occupants, but by figures who participated in the construction of the tombs based on political and social connections to their occupants. During the mid-fourth century, funeral practices in the former lands of the Nangnang and Daebang Commanderies followed Chinese traditions with the permission of Goguryeo Kingdom. Many of the artifacts found inside these Chinese-style tombs and introduced to the public, including the murals, ink inscriptions, and inscribed bricks, are related to the desire of the family members of the tomb occupants to strengthen their bonds and to share emotions and goals with settler groups. The contents of the inscribed bricks discovered from the Tomb of Jang Mui can be observed in this context.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1093-1101
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• 2000

The object of this study was to develop new BNR process using fixed-biofilm which could be applied to retrofit the existing wastewater treatment plant or to introduce as tertiary treatment plant. To achieve complete denitrification from typical raw sewage in Korea, external carbon source must be supplied because $SCOD_{cr}/T-N(NH_4{^+}-N+NOx-N)$of raw sewage was lower than other countries. In this study, the ratio of $SCOD_{cr}/NH_4{^+}-N$ was 2.49 and the influent $NH_4{^+}$-N concentration during the experimental period was varied from 25 to 37 mg/L. To enhance nitrogen removal from the sewage, the two processes using fixed biofilm were adopted as R-Hanoxic/mid.settler/aerobic/anoxic/ aerobic) and R-2(aerobic/mid.settlerlanoxic/anoxic/aerobic), respectively. In the comparison of $NH_4{^+}$-N, T-N effluent quality and T-N removal efficiency in both processes without external carbon source, R-1 process was better than R-2 process for nitrogen removal from raw sewage. With respect to $SCOD_{cr}$/NOx-N ratio and total nitrogen removal in each anoxic reactor of two processes, R-1's was more effective than R-2's for distributing organic matters of raw sewage. In the both processes using fixed biofilm, the amount of required alkalinity to remove unit $NH_4{^+}$-N were 5.18 and 5.76($g{\cdot}CaCO_3/g{\cdot}NH_4{^+}-N_{removed}$), respectively and were lower than activated sludge BNR process(7.14).