• Resources Recycling
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• v.8 no.5
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• pp.11-18
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• 1999

• Resources Recycling
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• v.9 no.3
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• pp.22-28
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• 2000

A study on the recovery of gallium from zinc residues is carried out by alkali leaching using NaOH. The results show that in case of alkali leaching of zinc residues, Zn, K and Si are mainly leached out and Fe and other base metals are scarcely leached out, which results in that gallium is easily recovered by solvent extraction. The leaching efficiency of gallium increases with increasing alkali concentration and solid density. Especially, alkali consumption is considerably reduced by washing the zinc residues with water before leaching in order to eleminate the soluble zinc compounds. The gallium from zinc residues is found to be leached out with a recovery of 80% or higher for 2hrs leaching with 1~1.25 M/L NaOH solution and solid density 333 g/L at $25^{\circ}C$.

• Resources Recycling
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• v.9 no.3
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• pp.29-36
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• 2000

A study on the recovery of gallium from leaching solutions is carried out by solvent extraction in order to produce gallium oxide of high purity. The results show that the extraction of gallium is found to be increase with acidities of aqueous solution up to 7.4 M/L when pure isopropyl ether is used. And the extraction of iron also increases with increasing acidity of aqueous solution. It appears that the separation of gallium from iron cannot be satisfactorily accomplished with isopropyl ether. But, in the case of extaction with D2EHPA, almost complete extraction of iron is achieved-leaving all the gallium in the aqueous solution-by maintaining the acidity of aqueous solution at 2 M/L. Accordingly, $Ga_2O_3{\cdot}H_2O$ of more than 99wt.% in purity can be produced from zinc residues through the processes comprising of alkali leaching, precipitation by neutralization and solvent extraction using isopropyl ether and D2EHPA as extractants.

• Proceedings of the Materials Research Society of Korea Conference
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• 1999.11a
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• pp.121-121
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• 1999

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2002.05a
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• pp.66-73
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• 2002

전기로제강분진을 적절한 공정을 통하여 처리하여 유가금속을 회수하고 처리잔사를 철원으로 재활용한다면 환경오염방지 및 폐자원의 재자원화 효과가 기대된다. 본 연구에서는 고온환원과 전해공정을 조합한 새로운 전기로제강분진 처리공정을 제안하고, 각 공정에 대한 기초실험을 수행하여 그 가능성을 조사, 검토 하였다. 전기로제강분진의 고온환원실험과 환원과정에서 분위기와 증기압의 차이를 이용한 Zn및 Pb 성분의 분리, 휘발실험의 결과들이 분석되었으며, 아울러 환원처리잔사 중의 Fe성분함량을 증가시켜 철원으로 재활용할 수 있는 가능성을 확인하기 위하여 전기로제강분진과 millscale을 혼합, 환원하는 실험을 수행하였다. 또한 환원과정의 휘발산물인 조산화아연의 침출 및 전해에 관한 기초실험을 수행하여 고순도금속아연회수의 가능성도 조사, 검토하였다.

• Resources Recycling
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• v.4 no.1
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• pp.46-51
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• 1995

After removal of mercury in the silver oxide batteries with the distillation process, the leaching of valuable metals from the residue was studied. The distilled residue was reacted with the various HNO, concentration, reactlon temperature, readion time and pulp density. It was found that the optimum condition for leachmg was 2N HNO,, 40-60% reaction temperature, 6 hours reaction tlme and 10g/200ml pulp density. More than 99% of silver and zinc were dissolved in this process while less than 50% of iron and nickel were leached

• Resources Recycling
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• v.2 no.2
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• pp.22-26
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• 1993

The flowsheet for the recovery of gallium and indium from zinc residues has been established based on the sulfuric acid treatment. In comparison with the alkali treatment, the method proposed in this work allowed the recovery of indium together with gallium. The majority of iron contained in leach liquor could be removed through the two-stage neutrallization under oxidative or reductive atmosphere. Crude gallium and indium could be obtained through the alkali and/or acid leaching of the products generated from the above treatment. In addition, cementation of indium with zinc powders could also be used for the concentration of it from weak acid solutions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.15 no.3
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• pp.201-206
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• 1986

The purpose of this study is to prepare the fish sauce front mackerel scrap which usually comprises $40{\sim}50%$ of raw fish in processing. Mackerel scrap was chopped, mired with equal weight of water, and then hydrolyzed by autolysis. The optimal conditions for hydrolysis of .mackerel scrap were at $55^{\circ}C$ for 4 hours. The maximum hydrolyzed rate of protein was 65% by autolysis. Crude protein content (6.5%) and color of mackerel sauce were similar to those of traditional soybean sauce. The abundant amino acids in mackerel sauce were leucine (22.8%), isoleucine (15.0%), phenylalanine (12.6%) and valine (12.5%). In sensory evaluation, mackerel sauce was at least equal to the traditional soybean sauce in product quality.

• Resources Recycling
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• v.7 no.2
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• pp.39-45
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• 1998

We smelted thc pellets made by mixing the distilled carbon from wlISte Lires, LD converter dust and slag with reduction process in the revcrberatory furnace. Thc obtained results are as follows 1) The removal mte of zinc appears above 97% after T reducing the pellets at $1300^{\circ}C$ for Ihr and the zinc content in the residue are 0.1~D.2%. 2) Under the mixing condition of 500 g LD dust. 150-200 g LD slag and 30-50 g distilled carbon of waste lires the removal raho of zinc shows above 95%, while t the 50-60% Fe remains in the residue. 3) After smelting at $1350^{\circ}C$ for 3hrs, the recovery ratio of pig iron reduced from lhe p pellets containing 15-20% LD slag and 4.1-7.2% distilled carbon of waste tires appears in the range of 89.3-92%. 4) Tbe c chemical composition of the recovered pig iron is 1.7%C, O.05%P, 0.05%S and balance Fe. 5) Tbe recovered dust from the d dust collcctor alter finishing the reduction rcaction appears as a crude zinc oxide conLaining 60% zinc.

• Resources Recycling
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• v.33 no.1
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• pp.15-21
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• 2024

The demand for electric vehicles powered by lithium-ion batteries is continuously increasing. Recovery of valuable metals from waste lithium-ion batteries will be necessary in the future. This research investigated the effect of reaction temperature on the lithium recovery ratio from hydrogen reduction followed by water leaching from lithium-ion battery NCM-based cathode materials. As the reaction temperature increased, the weight loss ratio observed after initiation increased rapidly owing to hydrogen reduction of NiO and CoO; at the same time, the H₂O amount generated increased. Above 602 ℃, the anode materials Ni and Co were reduced and existed in the metallic phases. As the hydrogen reduction temperature was increased, the Li recovery ratio also increased; at 704 ℃ and above, the Li recovery ratio reached a maximum of approximately 92%. Therefore, it is expected that Li can be selectively recovered by hydrogen reduction as a waste lithium-ion battery pretreatment, and the residue can be reprocessed to efficiently separate and recover valuable metals.