• Resources Recycling
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• v.33 no.3
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• pp.38-47
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• 2024

Molybdenite is the primary molybdenum resource and is extracted via flotation due to its unique hydrophobic surface. Meanwhile, the grade and crystal size of mined molybdenite are decreasing. As a result, the size of the molybdenum ore required for liberation is decreasing, and the flotation process's feed size input is also decreasing. Therefore, in order to secure molybdenum, it is necessary to perform research on the flotation for the fine molybdenite. In this study, we developed a method to enhance the flotation efficiency of fine molybdenite particles in the range of 5-30 ㎛. The methodology involved implementing bubble size reduction and particle aggregation. Through simulations of bubble-particle collision probability and flotation experiments, we were able to find the ranges of bubble size and particle aggregate size that make fine particles float more effectively. This range provided the conditions for effective flotation of fine molybdenite particles. Therefore, we will implement the flotation conditions established in this study for fine molybdenum ore to improve the flotation process in molybdenum mineral processing plants in the future.

• Resources Recycling
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• v.27 no.2
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• pp.11-23
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• 2018

The need for remanufacturing automotive parts is required due to the depletion of resources, rising raw material prices and strengthening environmental regulations. For remanufacturing, stable supply and demand of core must be accompanied. At present, remanufacturing companies collect cores through various routes, but the recovery rate of cores from the End-of-Life Vehicles is low. If we can systematically collect cores from hundreds of thousands of ELVs that were generated each year, the recovery rate of the core for remanufacturing will be further improved. Therefore, in this paper, we tried to establish a classification system for the ELV as a method for collecting the cores from the ELV. First, we selected the elements affecting the classification and determined the scope for the evaluation. The final rating classification is established by calculating the weights among the influence elements. Finally, through the case study, the dismantling grade of the actual ELV was evaluated to derive the second grade.

• Resources Recycling
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• v.3 no.1
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• pp.17-24
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• 1994

Recovery of precious metal values from petrochemical spent catalyst is important from the viewpoint of environmental protection and resource recycling. Two types of spent catalysts were used in this study. One used in the manufacture of ethylene contains 0.3% Pd in the alumina substrate. The other used in oil refining contains 0.3% Pt and 0.3% Re. Both spent catalysts are roasted to remove volatile matters as carbon and sulfur. Then, metallic Pd powder from Pd spent catalyst is obtained in the course of grinding, hydrochloric acid or aqua regia leaching and cementation with iron. For the recovery of Pt and Re from Pt-Re spent catalyst, Pt and Re are leached with either HCI or aqua regia, first. Metallic Pt powder is recovered from the leach solution by cementation with Fe powder. Re in sulfide form is precipitated by the addition of sodium sulfide to the solution obtained after Pt recovery. It is found that 6N HCI can be successfully used as leaching agent for both types of spent catalyst. 6N HCI is considered to be better than aqua regia in consideration of reagent and equipment cost.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.11
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• pp.2155-2161
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• 2016

Since Korea is highly dependent on energy imports, it has been making efforts to save energy resources by enacting laws to promote resource saving and recycling. Recently, as a part of recycling of empty bottles, a bottle unattended collecting machine has been installed in the big shopping mall in the metropolitan area. However, there is no commercialization of the unattended collecting machine in Korea and the smart device application for providing information on empty bottle recycling is not yet provided. In this paper, we have designed and constructed a bottle recycling information management system to promote resource recycling. The manager has built a homepage that can manage the information of the empty bottle and the a bottle unattended collecting machine. Also, many people with smart devices can easily access bottle recycling information by using camera and barcode search and label search.

• Resources Recycling
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• v.23 no.3
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• pp.3-12
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• 2014

This study aims at providing an economic assessment for incineration plants which recover heat during its incineration process. In this study, Life Cycle Cost(LCC) of incineration plants is performed based on each regression analysis formula for construction cost, operation cost, and heat generation in order to compare economic feasibility. The result shows that the incineration plant recovering waste heat while processing 80 tons of waste per day increases both initial investment and operation cost but this type of an incineration plant has economical predominance from the recovered waste heat over the one that does not recover heat when being operated for more than eleven years if the retrieved heat replaces the use of LNG. And its payback time reaches more than 19 years in case of selling heat and performing emission trading.

• Resources Recycling
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• v.21 no.6
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• pp.74-81
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• 2012

The Influence of temperature on the recovery reaction of silver in aqueous solution was investigated based on Pourbaix diagram constructed by thermodynamic calculation at different temperatures. It was observed that the stability of water is more strongly affected by pH variation and the stable region of ${Ag^+}_{(aq)}$ is diminished at higher temperature. It was shown that the recovery of $Ag_{(aq)}$ in the forms of $Ag_{(s)}$ and $Ag_2O_{3(s)}$ is more advantageous thermodynamically at lower temperature, however, the recovery of $Ag_{(aq)}$ in the forms of $Ag_2O_{(s)}$ 및 $Ag_2O_{2(s)}$ is more advantageous as temperature increases. The rise of temperature is considered to demote the recovery of silver thermodynamically in strong acidic condition ($pH{\leq}2$), but more silver is regarded to be recovered with temperature above pH 2. Finally, The recovery of silver in the elemental state is shown to be more sensitively influenced by temperature variation compared with the recovery of silver in its oxide form.

• Resources Recycling
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• v.26 no.4
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• pp.62-70
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• 2017

A cyclone type electrolytic method was used to recover silver from thiourea-hydrochloric acid mixed solutions. The electrowinning behavior of silver was investigated in different systems, such as the flow rate, current density, silver concentration, thiourea concentration and hydrochloric acid concentration. As the increase of the flow rate, current density and hydrochloric acid concentration, the recovery rate of silver was increased. Whereas, as the increase of silver concentration, the recovery rate of silver was decreased. The thiourea concentration did not affect the Ag recovery and current efficiency. Above 99% of Ag was recovered at the flow rate of 12 L/min., current density of $0.75A/dm^2$, silver concentration of 1.0 g/L, 0.5 M thiourea and 0.1 M hydrochloric acid. In most experimental conditions, silver was recovered as a powder form.

• The monthly packaging world
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• s.262
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• pp.90-93
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• 2015

버려지는 폐품을 자원으로 재활용하기 위한 노력이 활발하게 전개되고 있다. 특히 다양한 재질로 생산되는 포장재 회수 재활용은 환경을 지키고, 재활용 산업 육성이라는 두 마리 토끼를 잡는 효과를 올리고 있다. 그 핵심에는 한국포장재재활용사업공제조합(이하 공제조합)이 포장재 생산자와 재활용사업자 사이에서 가교 역할을 하며 자원순환 사회 구축을 위한 국가적 과제의 선도적 역할을 하고 있다. 공제조합은 공익법인으로 재출범된 지만 1년이 되었다. 올해 초 공제조합 수장으로 선임된 김진석 이사장을 만나 사업방향과 포부를 들어보았다.

• The monthly packaging world
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• s.226
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• pp.130-131
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• 2012

자원의 절약과 재활용촉진에 관한 법률 제17조제1항 및 같은 법 시행령 제22조에 따라 2012년에 재활용의무생산자가 재활용하여야 하는 제품 포장재별 재활용의무율과 전기 전자제품 및 자동차의 자원순환에 관한 법률 제16조 및 제20조의2, 같은 법 시행령 제14조 및 제21조의3에 따라 2012년에 전기 전자제품 제조 수입업자 및 판매업자가 재활용 회수하여야 하는 전기 전자제품별 재활용 회수의무율을 다음과 같이 결정 고시합니다.

• Resources Recycling
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• v.32 no.2
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• pp.3-11
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• 2023

The aim of this study was to develop a physical treatment method for obtaining iron concentrate with a grade higher than 60% from slag generated in the Waelz Kiln (WK) process. The size of the WK slag used in this work was several millimeters, with T-Fe and ZnO contents of 40.24% and 1.03%, respectively. The slag samples were pulverized in a laboratory rod mill for various grinding times, followed by a magnetic separation test under a low magnetic intensity of 0.05 T initially. The results showed that the highest iron grade was obtained from samples with a grinding time of 10 min. Additionally, for a grinding time of 20 min, the highest grade and recovery ratios were achieved at a magnetic intensity of 0.8 T. Based on these findings, the optimal physical treatment process proposed in this study resulted in iron concentrates with a grade of 61.34% and an enrichment ratio of 1.52.