• Title/Summary/Keyword: Recycling Behavior

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Crystal Structure Behavior of Vanadium-Titanium Magnetite (VTM) Ore by Planetary Ball Mill (바나듐 함유 티탄철광의 유성 볼밀에 의한 결정구조 거동)

  • Han, Yosep;Kim, Seongmin;Jung, Minuk;Jeon, Ho-Seok
    • Resources Recycling
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    • v.31 no.2
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    • pp.63-69
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    • 2022
  • In this study, mechanical grinding using a planetary ball mill was performed under various conditions to evaluate its effect on the crystal structure of vanadium titanium magnetite (VTM) ore from the Kwain Mine in South Korea. The crystal structure of the activated product was also evaluated. Magnetite and ilmenite were identified as the main types of VTM ore used in the Kwain Mine, and the main types of gangue minerals were iron-based silicate minerals. According to the mechanical activation results, the crystallinity and crystal size decreased as the size of the grinding media (balls) decreased, and the amorphization of the sample/ball filling was significant as the amount of the sample was reduced. In addition, as the grinding speed and time increased, the crystal structure significantly changed, proving that these two parameters had a greater effect on the crystal structure than the ball size and sample/ball filling ratio.

Development of Vanadium Recovery Process Using Reduction Pre-treatment from Vanadium Titanium-Magnetite (VTM) Ore (VTM광으로부터 환원 전처리를 이용한 바나듐 회수 공정 개발)

  • Go, Byunghun;Jeong, Dohyun;Han, Yosep;Kim, Seongmin;Chu, Yeoni;Kim, Byung-su;Jeon, Ho-Seok
    • Resources Recycling
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    • v.31 no.2
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    • pp.12-19
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    • 2022
  • The study was conducted to develop a vanadium recovery process using reduction pre-treatment in the Vanadium TitanoMagnetite (VTM) The sample for the research was provided by the Gwan-in Mine in Pocheon, Gyeonggi-do. The vanadium content of the sample is 0.54 V2O5% and vanadium is concentrated mainly in magnetite and ilmenite. Magnetic separation of the sample can increase vanadium content up to 1.10 V2O5%. To increase the vanadium content further, reduction pre-treatment was performed, which is a process of concentrating vanadium present in the iron by reducing iron in magnetite using carbon(C). Based on this reduction pre-treatment, the magnetic separation process was developed, which achieved a vanadium grade of 1.31V2O5% and 79.68% recovery. In addition, XRD analysis of the vanadium concentrate before and after reduction and the final vanadium concentrate was performed to confirm the behavior of vanadium by reduction pre-treatment.

Separation of Vanadium and Tungsten from Simulated Leach Solutions using Anion Exchange Resins (음이온교환 수지를 이용한 바나듐/텅스텐 혼합용액으로부터 바나듐/텅스텐 분리회수에 관한 연구)

  • Jong Hyuk Jeon;Hong In Kim;Jin Young Lee;Rajesh Kumar Jyothi
    • Resources Recycling
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    • v.31 no.6
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    • pp.25-35
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    • 2022
  • The adsorption/desorption behavior and separation conditions of vanadium and tungsten ions were investigated using a gel-type anion-exchange resin. In the adsorption experiment with the initial acidity of the solution, the adsorption rate of vanadium was remarkably low in strong acids and bases. Additionally, the adsorption rate of tungsten was low in a strong base. An increase in the reaction temperature increased the adsorption reaction rate and maximum adsorption. The effect of tungsten on the maximum adsorption was minimal. The adsorption isotherms of vanadium and tungsten on the ion-exchange resin were suitable for the Langmuir adsorption isotherms of both the ions. For tungsten, the adsorption isotherms of vanadium and tungsten were polyoxometalate. Both ion-exchange resins were simulated using similar quadratic reaction rate models. Vanadium was desorbed in the aqueous solutions of HCl or NaOH, the desorption characteristics of vanadium and tungsten depended on the desorption solution, and tungsten was desorbed in the aqueous solution of NaOH. It was possible to separate the two ions using the desorption process. The desorption reaction reached equilibrium within 30 min, and more than 90% recovery was possible.

Development of Composite Geo-Material for Recycling Dredged Soil and Bottom Ash (준설토와 Bottom Ash 재활용을 위한 복합지반재료 개발)

  • Kim, Yun-Tae;Han, Woo-Jong;Jung, Du-Hwoe
    • Journal of the Korean Geotechnical Society
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    • v.23 no.11
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    • pp.77-85
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    • 2007
  • This paper investigates the mechanical characteristics of composite geo-material which was developed to reuse both dredged soils and bottom ash. The composite geo-material used in this experiment consists of dredged soil taken from the construction site of Busan New Port, cement, air foam and bottom ash. Bottom ash is a by-product generated at the Samcheonpo thermal power plant. Several series of laboratory tests were performed to investigate behavior characteristics of composite gee-material, in particular the reinforcing effect by mixing bottom ash. The experimental results of composite geo-material indicated that the stress-strain relationship and the unconfined compressive strength are strongly influenced by mixing conditions. Especially it was observed that the compressive strength of composite geo-material increased with an increase in bottom ash content due to reinforcing effect by the bottom ash. Compressive strength of composite geo-material increased with the increase in curing time. The 28-day strength of composite geo-material is $1.7{\sim}1.8$ times higher than the 7-day strength. The moist unit weight strongly depended on air-foam content as well as bottom ash content added to the composite goo-material. In composite geo-material, secant modulus ($E_{50}$) also increased as its compressive strength increased due to the inclusion of bottom ash.

The Separation of Vanadium and Tungsten from Spent Selective Catalytic Reduction Catalyst Leach Solution by Alamine 336 (탈질 폐촉매 침출액으로부터 Alamine 336에 의한 바나듐과 텅스텐의 분리)

  • Seongsu Kang;Gyeonghye Moon;In-Hyeok Choi;Dakyeong Baek;Kyoungkeun Yoo
    • Resources Recycling
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    • v.33 no.3
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    • pp.30-37
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    • 2024
  • In this study, we investigated the separability of vanadium and tungsten from spent SCR (Selective Catalytic Reduction) catalyst leach solution by reduction of vanadium and solvent extraction using Alamine 336 and conducted experiments to optimize process conditions. It is difficult to separate vanadium and tungsten due to their similar chemical behavior, but tungsten can be selectively extracted from acidic solution when vanadium extraction is prevented by reducing anionic pentavalent vanadium to cationic tetravalent vanadium. The results showed that NaHSO3 was most suitable as a reducing agent, and the extraction efficiency of vanadium decreased and the separation efficiency increased as the amount of reducing agent added, reaction time, and temperature increased. When reducing NaHSO3 1.5 eq, 60 min, and 60℃, which are optimal conditions of reduction, vanadium and tungsten were effectively separated with vanadium extraction efficiency of 5.8%, tungsten extraction efficiency of 99%, and separation factor of vanadium and tungsten of 7,564.

Studies on The Reutilization of Used School Uniform of Middle and High School Students (중.고등학생의 교복 재활용 활성화에 관한 연구)

  • Shin, Hee-Sun;Oh, Kyung-Wha
    • Journal of Korean Home Economics Education Association
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    • v.21 no.1
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    • pp.141-155
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    • 2009
  • Purchasing used school uniforms is to reduce environmental pollution and expenses, and to enhance a feeling of wearing satisfaction for school uniforms by improving size fitting. In order to improve reutilization of used school uniforms, uniform purchasing behavior, awareness of the reutilizing markets of used school uniforms, and the running conditions of reutilizing markets of used school uniforms were analyzed through the survey. The subjects are 741 students of middle and high schools in Seoul and Kyeonggi Province in this study. The results are as follows. First, the better-fitted uniforms students wear, the higher satisfaction they feel. Therefore, it is desirable for students to wear the uniforms which are well fitted for each student. Second, the higher aware of environment students are and the more environmental preservation behavior they do, the higher awareness of wearing used school uniforms they are. In order to enhance students' awareness of reutilizing markets of used school uniforms, it is important to educate students about the environment systematically and to promote recycling events. Third, the reasons for not purchasing used school uniforms are difficulty in access to the repurchasing market and the sanitary problem. Therefore, it is suggested that environmental education which boosts students' awareness of environment and reutilization events should be held to make reutilizing markets of used school uniforms vigorous. Moreover, it is necessary to make reutilizing markets easy to access and improve cleaning and repairing system.

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A Fundamental Study on Shearing/Bonding Characteristics of Interface Between Rock Mass and Backfills in Mine Openings (폐광산 채움재와 암반 경계부의 전단 및 접합특성에 관한 기초 연구)

  • Kim, Byung-Ryeol;Lee, Hyeon-woo;Kim, Young-Jin;Cho, Kye-Hong;Choi, Sung-Oong
    • Tunnel and Underground Space
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    • v.31 no.6
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    • pp.623-646
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    • 2021
  • As the demand for electric power increases with acceleration of electrification at home and abroad, the needs for coal-fired electrical power plant are accordingly increased. However, these coal-fired electrical power plants induce also many environmental problems such as increase of air pollutants, increase of possibility of land contamination by reclamation of coal ash, even though these power plants have a good economical efficiency. In case of a by-product of coal-fired electrical power plants, only 70% of them are recycled and the remaining 30% of by-product are fully buried in surrounding ground. Consequently, this study deals with coal ash backfilling mechanism in abandoned mine openings for the purposes of increasing the coal ash recycling rate as well as securing the mine area stability. In order to analyze the backfill and ground reinforcement by interaction between rock mass and backfills, the copying samples of discontinuous surface with different roughnesses were produced for bond strength tests and direct shear tests. And statistical analysis was also conducted to decide the characteristics of bond and shear behavior with joint roughness and their curing day. Numerical simulations were also analyzed for examining the effect of interface behavior on ground stability.

Electrochemical Behaviors of Graphite/LiNi0.6Co0.2Mn0.2O2 Cells during Overdischarge (흑연과 LiNi0.6Co0.2Mn0.2O2로 구성된 완전지의 과방전 중 전기화학적 거동분석)

  • Bong Jin Kim;Geonwoo Yoon;Inje Song;Ji Heon Ryu
    • Journal of the Korean Electrochemical Society
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    • v.26 no.1
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    • pp.11-18
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    • 2023
  • As the use of lithium-ion secondary batteries is rapidly increasing due to the rapid growth of the electric vehicle market, the disposal and recycling of spent batteries after use has been raised as a serious problem. Since stored energy must be removed in order to recycle the spent batteries, an effective discharging process is required. In this study, graphite and NCM622 were used as active materials to manufacture coin-type half cells and full cells, and the electrochemical behavior occurring during overdischarge was analyzed. When the positive and negative electrodes are overdischarged respectively using a half-cell, a conversion reaction in which transition metal oxide is reduced to metal occurs first in the positive electrode, and a side reaction in which Cu, the current collector, is corroded following decomposition of the SEI film occurs in the negative electrode. In addition, a side reaction during overdischarge is difficult to occur because a large polarization at the initial stage is required. When the full cell is overdischarged, the cell reaches 0 V and the overdischarge ends with almost no side reaction due to this large polarization. However, if the full cell whose capacity is degraded due to the cycle is overdischarged, corrosion of the Cu current collector occurs in the negative electrode. Therefore, cycled cell requires an appropriate treatment process because its electrochemical behavior during overdischarge is different from that of a fresh cell.

Consumer Awareness and Evaluation of Retailers' Social Responsibility: An Exploratory Approach into Ethical Purchase Behavior from a U.S Perspective (소비자인지도화령수상사회책임(消费者认知度和零售商社会责任): 종미국시각출발적도덕구매행위적탐색성연구(从美国视角出发的道德购买行为的探索性研究))

  • Lee, Min-Young;Jackson, Vanessa P.
    • Journal of Global Scholars of Marketing Science
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    • v.20 no.1
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    • pp.49-58
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    • 2010
  • Corporate social responsibility has become a very important issue for researchers (Greenfield, 2004; Maignan & Ralston, 2002; McWilliams et al., 2006; Pearce & Doh 2005), and many consider it necessary for businesses to define their role in society and apply social and ethical standards to their businesses (Lichtenstein et al., 2004). As a result, a significant number of retailers have adopted CSR as a strategic tool to promote their businesses. To this end, this study sought to discover U.S. consumers' attitudes and behavior in ethical purchasing and consumption based on their subjective perception and evaluation of a retailer. The objectives of this study include: 1) determine the participants awareness of retailers corporate social responsibility; 2) assess how participants evaluate retailers corporate social responsibility; 3) examine whether participants evaluation process of retailers CSR influence their attitude toward the retailer; and 4) assess if participants attitude toward the retailers CSR influence their purchase behavior. This study does not focus on actual retailers' CSR performance because a consumer's decision making process is based on an individual assessment not an actual fact. This study examines US college students' awareness and evaluations of retailers' corporate social responsibility (CSR). Fifty six college students at a major Southeastern university participated in the study. The age of the participants ranged from 18 to 26 years old. Content analysis was conducted with open coding and focused coding. Over 100 single-spaced pages of written responses were collected and analyzed. Two steps of coding (i.e., open coding and focused coding) were conducted (Esterberg, 2002). Coding results and analytic memos were used to understand participants' awareness of CSR and their ethical purchasing behavior supported through the selection and inclusion of direct quotes that were extracted from the written responses. Names used here are pseudonyms to protect confidentiality of participants. Participants were asked to write about retailers, their aware-ness of CSR issues, and to evaluate a retailer's CSR performance. A majority (n = 28) of respondents indicated their awareness of CSR but have not felt the need to act on this issue. Few (n=8) indicated that they are aware of this issue but not greatly concerned. Findings suggest that when college students evaluate retailers' CSR performance, they use three dimensions of CSR: employee support, community support, and environmental support. Employee treatment and support were found as an important criterion in evaluation of retailers' CSR. Respondents indicated that their good experience with a retailer as an employee made them have a positive perception and attitude toward the retailer. Regarding employee support four themes emerged: employee rewards and incentives based on performance, working environment, employee education and training program, and employee and family discounts. Well organized rewards and incentives were mentioned as an important attribute. The factors related to the working environment included: how well retailers follow the rules related to working hours, lunch time and breaks was also one of the most mentioned attributes. Regarding community support, three themes emerged: contributing a percentage of sales to the local community, financial contribution to charity organizations, and events for community support. Regarding environments, two themes emerged: recycling and selling organic or green products. It was mentioned in the responses that retailers are trying to do what they can to be environmentally friendly. One respondent mentioned that the company is creating stores that have an environmentally friendly design. Information about what the company does to help the environment can easily be found on the company’s website as well. Respondents have also noticed that the stores are starting to offer products that are organic and environmentally friendly. A retailer was also mentioned by a respondent in this category in reference to how the company uses eco-friendly cups and how they are helping to rebuild homes in New Orleans. The respondents noticed that a retailer offers reusable bags for their consumers to purchase. One respondent stated that a retailer uses its products to help the environment, through offering organic cotton. After thorough analysis of responses, we found that a participant's evaluation of a retailers' CSR influenced their attitudes towards retailers. However, there was a significant gap between attitudes and purchasing behavior. Although the participants had positive attitudes toward retailers CSR, the lack of funds and time influenced their purchase behavior. Overall, half (n=28) of the respondents mentioned that CSR performance affects their purchasing decisions making when shopping. Findings from this study provide support for retailers to consider their corporate social responsibility when developing their image with the consumer. This study implied that consumers evaluate retailers based on employee, community and environmental support. The evaluation, attitude and purchase behavior of consumers seem to be intertwined. That is, evaluation is based on the knowledge the consumer has of the retailers CSR. That knowledge may influence their attitude toward the retailer and thus influence their purchase behavior. Participants also indicated that having CSR makes them think highly of the retailer, but it does not influence their purchase behavior. Price and convenience seem to surpass the importance of CSR among the participants. Implications, recommendations for future research, and limitations of the study are also discussed.

Effect of Scrap Impurities on Microstructure and Mechanical Properties of Zr Alloys (스크랩 불순물이 Zr 합금의 미세조직 및 기계적 특성에 미치는 영향)

  • Jeong, Gu Beom;Kim, In Won;Song, Jae Sook;Shin, Pyung Woo;Hong, Sun Ig
    • Journal of Korea Foundry Society
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    • v.36 no.3
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    • pp.81-87
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    • 2016
  • In this study, the effect of scrap ratio on the mechanical properties of Zr alloys was studied. Oxygen content in the ingot cake increased rapidly with increasing fraction of scrap, which can be attributed to the surface oxide of scrap including small pieces of turning, chips, etc. Iron content did not increase much with the increasing addition of scrap, suggesting scrap materials was well reserved in the iron-free container. As-cast structure of Zr alloy with the scrap:sponge ratio displayed plate/or needle ${\alpha}$ phase and no appreciable change of the cast structure was observed with change of scrap fraction. The strength increases with increasing fraction of scrap, which can be attributed to the increase of oxygen content. The ductility decreased slightly with increase of scrap fraction. Dislocation-oxygen interaction is known to increase the strength at the expense of ductility. Ingot cake with intentionally added $Fe_2O_3$ exhibited the drastic decrease of the formability, even exhibited the brittle fracture behavior during rolling. The oxidation resistance, however, increased with the increase of scrap fraction because of high oxygen content, which may prevent more penetration and diffusion of oxygen into matrix.