• Computers and Concrete
• /
• 제33권1호
• /
• pp.41-53
• /
• 2024

Under constant and cyclic axial compression, square composite short columns reinforced with Self Compacting Concrete (SCC) added with scrap rubber infilled inside steel tubes and with different types of concrete were cast and tested. The test is carried out to find the effectiveness of utilizing an aggregate manufactured from industrial waste and to address the problems associated with the need for alternative reinforcements along with waste management. The main testing parameters are the type of concrete, the effect of fiber inclusion, and the significance of rubber-infilled steel tubes. The failure modes of the columns and axial load-displacement curves of the steel tube-reinforced columns were all thoroughly investigated. According to the test results, all specimens failed due to compression failure with a longitudinal crack along the loading axis. The fiber-reinforced column specimens demonstrated improved ductility and energy absorption. In comparison to the normal-weight concrete columns, the lightweight concrete columns significantly improved the axial load-carrying capacity. The addition of basalt fiber to the columns significantly increased the yield stress and ultimate stress to 9.21%. The corresponding displacement at yield load and ultimate load was reduced to 10.36% and 28.79%, respectively. The precision of volumetric information regarding the obtained crack quantification, aggregates, and the fiber in concrete is studied in detail through image processing using MATLAB environment.

• 자원리싸이클링
• /
• 제23권3호
• /
• pp.61-70
• /
• 2014

주석은 땜납, 주석도금강판, 청동 합금, 투명전극용 타겟 및 화학첨가제 등에 널리 사용되고 있다. 최근 자원의 희소성 및 경제성으로 인해 주석 스크랩에 대한 재활용 기술이 연구되고 있다. 본 논문에서는 주석이 함유된 공정 스크랩, 슬러지, 도금 폐액 및 합금의 재활용 기술에 대하여 1970년부터 2013년까지 공개/등록된 한국, 미국, 중국, 일본, 유럽의 특허에 대하여 조사하였다. 특허는 키워드를 사용하여 수집하였으며, 기술의 정의에 의해 필터링 하여 연도, 국가, 출원인 및 기술에 따라 분석하였다.

• 자원리싸이클링
• /
• 제20권6호
• /
• pp.3-18
• /
• 2011

우리나라의 도시광산 재자원화실태와 전망을 파악하기 위하여 금속소비량을 산출하였다. 년간 금속소비량으로부터 금속 축적량을 추정할 수 있고, 도시광산자원을 전망할 수 있다. 금속소비량을 산출함에 있어 다양한 자료 즉 비철협회, 철강협회, 관세청 HS 코드, 연구용역 보고서, 학술회의자료 및 생산회사 탐문자료 등을 인용하였다. 도시광산개발의 요건(key point)을 설명하기 위하여 T.E.Graedel에 의해서 작성된 표(Principle Uses and Recycling Potential of Metals in the Periodic Table)를 인용하였다.

• 자원리싸이클링
• /
• 제28권5호
• /
• pp.30-41
• /
• 2019

아연의 전세계 생산량은 약 1,300만 톤 정도이며, 철, 알루미늄, 구리에 이어서 네 번째로 많이 사용되는 금속이다. 아연을 리사이클링하여 2차지금을 생산하는 경우 광석으로부터 1차지금을 생산하는데 필요한 에너지의 약 75 %를 절약할 수 있으며, $CO_2$ 발생량은 약 40 %를 절감할 수 있다. 그러나 아연의 주 용도가 철강재의 도금용이기 때문에 아연의 리사이클링율은 약 25 % 수준으로 다른 금속보다 낮은 수준이다. 아연의 리사이클링 원료에는 제강분진, 황동 제조시에 발생하는 분진, 비철금속의 제조공정에서 발생하는 슬러지, 아연 잉곳의 재용해나 용융아연도금을 할때 생성되는 드로스, 폐건전지, 그리고 금속성 스크랩 등이 있다. 제강분진과 폐건전지가 가장 활발하게 리사이클링 되고 있다. 이러한 리사이클링 공정의 대부분은 건식제련법을 응용하고 있으나, 최근에는 건식과 습식의 복합처리에 관해서도 많은 관심이 주어져 있다.

• 방사성폐기물학회지
• /
• 제18권4호
• /
• pp.481-496
• /
• 2020

After nuclear power plants are permanently shut down and decommissioned, the remaining irradiated metal components such as stainless steel, carbon steel, and Inconel can be used as neutron absorber. This study investigates the possibility of reusing these metal components as neutron absorber materials, that is burnable poison. The absorption cross section of the irradiated metals did not lose their chemical properties and performance even if they were irradiated over 40-50 years in the NPPs. To examine the absorption capability of the waste metals, the lattice calculations of WH 17×17 fuel assembly were analyzed. From the results, Inconel-718 significantly hold-down fuel assembly excess reactivity compared to stainless steel 304 and carbon steel because Inconel-718 contains a small amount of boron nuclide. From the results, a 20wt% impurity of boron in irradiated Inconel-718 enhances the excess reactivity suppression. The application of irradiated Inconel-718 as a burnable absorber for SMR core was investigated. The irradiated Inconel-718 impurity with 20wt% of boron content can maintain and suppress the whole core reactivity. We emphasize that the irradiated metal components can be used as burnable absorber materials to control the reactivity of commercial reactor power and small modular reactors.

• 한국해양공학회지
• /
• 제37권6호
• /
• pp.266-272
• /
• 2023

The structure of a ship is completed by processing various steel plates and welding these plates. This butt welding of plates is defined as a seam in shipyards, and this study seeks to find a way to decrease costs by reducing the utilization of steel through effective seam arrangement. Seams were defined and classified according to purpose, and examples of "pieces" and "main plates" where seam creation had an economical saving effect were selected. For "pieces," the change in the weight of steel utilized depending on the presence or absence of a seam was calculated, and the resulting change in cost increase was presented. In the case of the "main plate," the quantity of seams does not change, but an example of cost variation due to the appropriate placement of seams is presented. Hence, a large difference was found in the costs of "pieces" depending on seam location. Thus, it was advantageous to create additional seams. For the "main plate," it was found that narrow-width and wide-width materials incur more costs. This study demonstrates that creating seams is economically advantageous but may not be preferred owing to the increased workload from a production perspective.

• 한국기계가공학회지
• /
• 제14권4호
• /
• pp.146-150
• /
• 2015

Steel is produced through the steel-making process with a desired shape by a rolling press. Scrap is removed according to the sheet edge to improve the quality of the product. This machine is called a side trimmer. This study aimed to develop a side trimmer for automatically changing the width of the trimming knife without line stopping. This machine consists of a housing opening device and a turning device. The measuring technologies of sheet width, trimming knife rotation angle, and knife gap for increasing the control accuracy. This experiment was conducted to evaluate the performance of the developed technologies. It was reduced by 10% compared with the operation time of the conventional method.

• 자원리싸이클링
• /
• 제28권3호
• /
• pp.21-25
• /
• 2019

The utilization of incineration ash from municipal waste must be promoted to solve the social problem on the shortage of final disposal site. In this research, metals should be recovered to avoid the damage of the crushing machine during the utilization of incineration ash in cement industry. In fact, incineration bottom ash from municipal waste contains iron in 3-5%. Nonferrous metal and stainless steel in 1% is also included. The research and development on the physical recovery process was performed not only to remove the metals but also to recover high grade products. Metals were separated from incineration ash in Maruya Co. Ltd.. In fact, iron scrap recovered by magnetic separation can be selled. After that, mixed metal was separated from incineration ash using screen. In this research, mixed metal tried to divided copper, aluminum, brass and stainless steel using drum type magnetic separation, eddy current separation and high magnetic separation. As a result, recovered iron had an 80% for the grade. Aluminum was recovered by eddy current separation without copper and brass.

• 산업기술연구
• /
• 제17권
• /
• pp.169-174
• /
• 1997

This investigation was carried out to study on the generation property, management and seperate collection rate of solid waste in the Gu-Gok Falls. Generation rate of solid waste was 80.785kg/day and unit waste generation rates was $65.55g/day{\cdot}tourist$ one person. Physical component of solid waste were garbage 46%, papers 20%, empty bottles 10%, respectively. A plan is required to decrease generation rate of garbage waste. As result to investigate separated garbage can, papers and can were separated more than 60%. But empty bottles and scrap iron were separated less than 50%. P.E.T, steel can, aluminum can and empty bottles were 20% of total generation rate, and profit of reuse is \700,800/year.

• 한국세라믹학회지
• /
• 제56권1호
• /
• pp.77-83
• /
• 2019

MgO-C refractories are used in basic furnaces and steel ladles due to their many desirable properties, such as excellent thermal shock resistance via low thermal expansion, and high thermal conductivity. However, the mechanical and thermal properties of the refractory continuously deteriorate by spalling phenomena and pore generation due to the oxidation of graphite, used as a carbon source, indicating that the characteristics and performance of MgO-C refractories need to be improved by using a new material or composition. In this study, the use of a Hertzian indentation test as a method for determining the damage and fracture behavior of an MgO-C refractory is described. The results highlight that Hertzain indentation tests can be one of the important evaluation tools for quasi-plastic damage accumulation of MgO-C refractories during falling process of scrap metal.