• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.89-90
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• 2014

인쇄회로기판 패턴도금 박리공정 중 발생하는 폐솔더 박리액은 주석, 구리, 철, 납 등 유가금속이 함유된 질산계 폐액이다. 본 연구에서는 이러한 폐솔더 박리액에서 질산과 유가금속을 체계적으로 회수하는 기술을 개발하고자 하였다. 먼저 폐액을 $80^{\circ}C$에서 3시간 정도 반응시켜 주석을 $SnO_2$ 상태로 90% 이상 회수가 가능하였다. 주석이 회수되고 구리, 철, 납만이 존재하는 질산계 폐솔더 박리액에서 확산투석을 이용하여 질산을 94% 이상 회수가 가능하였고 회수된 질산의 농도는 5.1 N 이었다. 질산을 추출한 폐액에서 침전제로 옥살산(Oxalic acid)을 사용하여 구리를 구리옥살레이트 상태로 침전시켜 타금속이온과 선택적으로 분리하였다. 마지막으로 폐액 중 용해되어있는 납을 $65^{\circ}C$이상에서 철 스크랩을 이용한 세멘테이션을 통하여 회수하였다.

• Resources Recycling
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• v.6 no.3
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• pp.3-8
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• 1997

The EA.F. sleelmaking slag (slag that follow) of a cnmvany 1 Co.. containzd a simple substance of a metal, wustlte (FeO), magnetite (Fe,O,), gehlenite (CaAl,SiO,), monlicellite (CaMgSiO,), dc. To recovere a metal (Fe grade . t95%) in the slag, it is desirable that the particles of a metal are isolated from thc slag and madc for a liberated subslance. Then, the liberaled melal is easlly recoveled by a magnetic separation. If thc rcclarnalcd slag, the sizc of which ranges under 40 nun, have a mulli-stage crushing, the most of a metal in thc slag is simply isolaled as a liberated subslance. If the mad, lhat is a liberated subslance and a sphere, is recovered by a magnetic field intensity. the minimum intensity, at which a metal is attracted, is approximately IOOG and did no1 dcpcnd on the particle size of a metad in the same particles. TIe recovered material. that contdined a iron (Fe) over 95% is a metal which is crushed slag by l00G in the multi-stage. If the magnetic field intcns~ty increase, the recovery mcrcasc, but the concentration grade decrease Bewusc thc concentration eams more and more impurities, iron oxide and the coml~ound of alkali earth element. 'll~ercforc If the rccla~nated slag have the multi-stage crushing, the metal is almostly recovered in the crushed slag by lO0G on each particles. If the slag, used as a rcclamatian lhat is a amount of 350,000 tan from I Co., was undcr the multistage crushing and then separaled by 100gauss, it is possible to recova a metal approximately 2.500 Ion, lhat is 0.73% of n ~eclamated slag. in 304.7 mm particles and to recover 4.200 tan in 0.3-1.7 mm particles , that is 1.2% nf a rcclamated slag, in a year. Therefore, ihe told recoverable meld is 6,700 ton, that is 19% of a reclmated slag, in a year, too.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.05a
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• pp.228-230
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• 2005

본 연구에서는 생활 폐기물의 소각 바닥재를 사용하여 입도 분리한 후 각 입도별 철 비철 금속이 함유된 바닥재를 자력세기에 따라 분리하였다. 철의 분석결과 4mesh이상의 입자에서 대부분의 철이 회수되었고 4mesh이하에서는 철의 함유량이 적었지만 50mesh 이하의 입자에서는 자력에 의해 대부분 분리되었다. 또한 각 입도에 따른 자력세기별로 철의 회수율을 측정한 결과 $25{\sim}130gauss(30{\sim}150volt)$에서는 낮은 회수율을 보였고 380gauss(150volt이상)의 높은 자력에서만 분리가 일어남을 확인할 수 있었다. 비철은 대부분 4mesh에서 분포하였고 전체적으로 낮은 양이 존재하였다.

• Clean Technology
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• v.27 no.3
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• pp.240-246
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• 2021

The waste etching solution for chip on film (COF) contained about 3.5% copper, and it was recovered through cementation using iron samples. The effect of cementation with plate, chip, and powder iron samples was investigated. The molar ratio (m/r) of iron to copper was used as a variable in order to increase the recovery rate of copper. As the molar ratio increased, the copper content in the solution rapidly decreased at the beginning of the cementation reaction. Before and after the reaction, the copper content of the solution was determined by Inductively Coupled Plasma (ICP) using copper concentration according to time. After cementation at room temperature for 1 hour, the recovery rate of copper had increased the most in the iron powder sample, having the largest specific surface area of the samples, followed by the chip and plate samples. The recovered copper powder was characterized for its crystalline phase, morphology, and elemental composition by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDS), respectively. Copper and unreacted iron were present together in the iron powder samples. The optimum condition for recovering copper was obtained using iron chips with a molar ratio of iron to copper of 4 giving a recovery rate of about 98.4%.

• Resources Recycling
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• v.15 no.6 s.74
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• pp.41-47
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• 2006

A study for recovering of copper and lead from electronic scraps has been carried out using a combination of bioleaching and solvent extraction. It was found that the citric acid generated by Aspergillus niger could be an imporant leaching agent acting in the solubilization of copper, iron, lead and tin from the electronic scrap. Copper could be selectively extracted by 10% LIX84 from the leaching solution and it recoved 99.9% of metallic copper by electrowinning process. Tin and iron were extracted from the remaining solution by 10% Alamine336 and stripped by NaCl solution. Finally, tin could be recovered as a metallic precipitates from the mixed solution of tin and iron by cementation with iron powder.

• Resources Recycling
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• v.13 no.2
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• pp.3-8
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• 2004

A basic study on the recovery of heavy metals such as Zn, Ni, Cu and Fe ions from wastewater was carried out with the spent iron oxide catalyst, which was used in the Styrene Monomer(SM) production company. The heavy metals could be recovered more than 98％ with the spent iron oxide catalyst. The alkaline components of the spent catalyst could be precipitated the metal ions of the wastewater as metal hydroxides at the higher pH 10.6 in Ni, pH 8.0 in Cu, pH 6.5 in Fe, pH 8.5 in Zn. But the metal ions are adsorbed physically on the surface of the spent catalyst in the range of the pH of the metal hydroxides and pH 3.0, which is the isoelectric point of the iron oxide catalyst.

• Resources Recycling
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• v.23 no.3
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• pp.30-36
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• 2014

A large amount of waste copper slag containing about 35 ~ 45% iron has been generated and discarded every year from pyrometallurgical processes for producing copper from copper concentrate. Thus, recovery of iron from the waste copper slag is of great interest for comprehensive use of mineral resource and reduction of environment problems. In this study, a physico-chemical separation process for upgrading iron from the waste copper slag discharged as an industrial waste has been developed. The process first crushes the waste copper slag below 1 mm (first crushing step), followed by carbon reduction at $1225^{\circ}C$ for 90 min (carbon reduction step). And then, resulting material is again crushed to $-104{\mu}m$ (second crushing step), followed by wet magnetic separation (wet magnetic separation step). Using the developed process, a magnetic product containing more than 66 wt.% iron was obtained from the magnetic separation under a magnetic field strength of 0.2 T for the waste copper slag treated by the reduction reaction. At the same conditions, the percentage recovery of iron was over 72%. The iron rich magnetic product obtained should be used as a iron resource for making pig iron.

• Clean Technology
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• v.30 no.1
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• pp.28-36
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• 2024

As demand for electric vehicles increases, the market for lithium-ion batteries is also rapidly increasing. The battery life of lithium-ion batteries is limited, so waste lithium-ion batteries are inevitably generated. Accordingly, lithium was selectively preleached from waste lithium iron phosphate (LiFePO₄, hereafter referred to as the LFP) cathode material powder among lithium ion batteries, and iron phosphate (FePO₄) powder was recovered. The recovered iron phosphate powder was mixed with alkaline sodium carbonate (Na₂CO₃) powder and heat treated to confirm its crystalline phase. The heat treatment temperature was set as a variable, and then the leaching rate and powder characteristics of each ingredient were compared after water leaching using Di-water. In this study, lithium showed a leaching rate of approximately 100%, and in the case of powder heat-treated at 800 ℃, phosphorus was leached by approximately 99%, and the leaching residue was confirmed to be a single crystal phase of Fe₂O₃. Therefore, in this study, lithium, phosphorus, and iron components were individually separated and recovered from waste LFP powder.

• Clean Technology
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• v.28 no.2
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• pp.103-109
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• 2022

Nd-Fe-B waste permanent magnet contains about 20~30% rare earth elements and about 60~70% iron elements, and the rare earth and iron components were recovered through sulfuric acid leaching and fractional crystallization. Oxidation roasting was not performed for separation and recover of the rare earth and iron elements. The leaching characteristics were confirmed by using as variables the sulfuric acid concentration and the mineral solution concentration ratio. Sulfuric acid leaching was carried out for 3 hours for each sulfuric acid concentration. The leached solid phase was characterized for its crystalline phase, composition, and quantitative components by XRD and XRF analysis, and the filtrate was analyzed for components by ICP analysis. With sulfuric acid leaching at 3M sulfuric acid concentration, neodymium compounds were formed, the iron content was the least, and the recovery rate was high. After the filtrate remaining after sulfuric acid leaching was subjected to fractional crystallization through evaporation and concentration, the neodymium component was found to be concentrated 7.0 times and the iron component 2.8 times. In this study, the recovery rate of waste permanent magnets through sulfuric acid leaching and a fractional crystallization method without an oxidation and roasting process was confirmed to be about 99.4%.

• Monthly Korean Chicken
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• v.14 no.11
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• pp.114-118
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• 2008