• Journal of Environmental Health Sciences
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• v.39 no.3
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• pp.248-255
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• 2013

Objectives: The purpose of this paper is to define the level of recycling standards and its process in paper scrap. As pollution is increased by improperly treated paper scrap, the government has recently strengthened the management of the paper scrap. Methods: In this study, the current status of paper scrap recycling was investigated through a 2012 field survey, and the classification and recycling standards for paper scrap in developed countries and institutions were also investigated through a literature review in order to introduce optimal recycling standards. Results: As a result, the contents of contaminants were identified as the most important recycling standard, and the contents of contaminants in paper scrap was measured at less than 1.0% at most companies. The recycling standard for paper scrap was determined to be below 3% contaminants in the case of paper and 5% in the case of board. In this study, recycling stage was determined by considering regulations on resources and practices in the field. Conclusions: The recycling standard for paper scrap was determined to be below 3% and 5% contaminants for paper and board, respectively.

• Resources Recycling
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• v.28 no.2
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• pp.3-13
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• 2019

Aluminum is the most abundant metal and the second most plentiful metallic element in the earth's crust, after silicon. Aluminum is a light, conductive, and corrosion resistant metal with strong affinity for oxygen. However, the primary aluminum production process is highly energy intensive. The recycling of aluminum scrap reduces the energy consumption and environmental burden, comparing to the primary metal production. However, the amount of the recovered metal from scrap is limited because of the difficulties to remove the impurities in the scrap. This work provides an overview of the aluminum production and recycling process, from the preparation of alumina to the scrap upgrading and the melting process.

• Resources Recycling
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• v.27 no.6
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• pp.76-83
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• 2018

This article aims to summarize the scrap recycling status of gold, silver, platinum and palladium from foreign countries by courntires and industries in order to utilize the data for securing the raw materials of the domestic urbanmining industry. The amount of gold from scrap has shown a tendency to decrease in countries other than China, which is attributed to the large imports of scrap containing gold in China. The industry demand for gold is the highest in electronic products, but demand is decreasing. The amount of scrap recycling in silver has declined in other regions compared to those in Europe, indicating that the world's overall scrap recycling volume has declined. Production and demand from scrap of platinum and palladium are mostly for catalysts and have been steadily increasing until now. However, it is expected that the amount of waste catalysts in automobiles will decrease with the increase of electric vehicle use.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.230-235
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• 2001

There are more than 15 millions cars or motors in Taiwan. According to the statistics from Environmental Protection Administration, the number of resulting scrap tires are near 110 thousand tons each year. The tire recycle programs in Taiwan were first conducted in 1989 and executed by ROC Scrap Tire Foundation. However, the current efficiency of the tire recycling industry still needs to be improved to minimize the environmental problem or fire hazards caused by scrap tires storage. Ten major tire-recycling factories are surveyed in this study. The investigations include the source of scrap tire, the shredding process, the market of products, the management of wastes disposal, and the difficulties of these sectors. As the varieties of the shredding machines of the recycle factories, there are three kinds of final products which include powder, granular, and chips. The wastes, wires and fibers, produced by the shredding process are the major problems fur all the factories. The percentage of the wire and fiber removal from rubbers still needs to be increased. The best approaches found in this study to increase the efficiency of scrap tire recycling processes are proposed which include the improvement of magnetic separation system fiber/rubber separation system and the minimization of waste disposal. A categorized standard of the processing outputs is suggested as a reference for the decision-making of the tire-recycling factories.

• Resources Recycling
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• v.29 no.5
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• pp.3-14
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• 2020

Magnesium is the third most abundant structural metal after aluminum and iron. Magnesium is the lightest metal in the common metals. It has a density 33 % less than aluminum and 77% lower than steel. However, the primary magnesium production process is highly energy intensive. The recycling of magnesium scrap reduces the energy consumption and environmental burden, comparing to the primary metal production. However, the amount of recovered metal from scrap is limited because of the difficulties to remove the impurities in the scrap. This work provides an overview of the magnesium production and recycling process.

• Resources Recycling
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• v.30 no.1
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• pp.26-34
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• 2021

Titanium is the fourth most abundant structural metal, after aluminum, iron, and magnesium. However, it is classified as a 'rare metals', because it is difficult to smelt. In particular, the primary titanium production process is highly energy-intensive. Recycling titanium scraps to produce ingots can reduce energy consumption and CO2 emissions by approximately 95 %. However, the amount of metal recycled from scrap remains limited of the difficulty in removing impurities such as iron and oxygen from the scrap. Generally, high-grade titanium and its alloy scraps are recycled by dilution with a virgin titanium sponge during the remelting process. Low-grade titanium scrap is recycled to ferrotitanium (cascade recycling). This paper provides an overview of titanium production and recycling processes.

• Resources Recycling
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• v.4 no.3
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• pp.10-18
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• 1995

Recycling of GaAs scrap which occurs durmg the manufachre of GaAs waters is. therefore, required to solve the environmentalproblcrns caused by arsenic metal and to reutilize gallium which is a expensive metal. A thema-analyticalstudy (thermogravimeg. and derivative thermogravimetry) tor the evaporation behavior of Fa, As from Gak\ulcorner scrap powdersat vacuum atmosphere(2-2.5X 10'mmHg); was primarily performed to identi j the possibility of Ga extraction. Until79YC, the weight change of G d s porvder does not take place, at 800-970C range GaAs vaporizes as the GaAs compound,and over 1WO"C it decamposes mto Ga and As md then As vaporizes rapidly as a result of the difference af vaporprcssure for Ga and As, liquid Ga rcmains eventually.mains eventually.

• Korea Trade Review
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• v.46 no.2
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• pp.121-140
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• 2021

The ship recycling or scrap is a phenomenon in the process of vessels life cycle has ended in the shipping industry. Scrap are greatly affected by freight rates due to ship demands. Not only that, environmental regulation and economic scale vessel demand are processes that must exist in the shipping industry as they obtain management for existing vessels. In the past, shipbreaking yard had tried to work without protection for poverty, without poor working conditions and facilities to prevent the emission of harmful substances. However, the issue of environmental pollution has been raised the Basel and Hong Kong Convention have been adopted, and a new replacement of the ship scrap that induces serious pollution is required. In this study, 165 countries were analyzed to confirm the importance of determining the ship solution. As a result of the analysis, it was found that the Environmental Performance Index, which is a measure of environmental regulation, is the most influential factor of ship scrapped volume. The determinant of whether lower labor cost can be secured is more correlated with population than GDP per capita. The implications of the results of the regression analysis mean that if environmental regulations for ship scrap of the future are strengthened, the status of Bangladesh and Pakistan, which currently account for half of the world's ship recycling, may change.

• Korean Journal of Materials Research
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• v.21 no.12
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• pp.673-678
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• 2011

With an increased production of Printed Circuit Boards (PCBs) in electronic equipment, the consumption of solder alloys is growing globally. Recently, increasing importance of recycling solder scrap has been recognized. Generally, solder scrap contains many impurities such as plastics and other metals. Hazardous components must be eliminated for recycling solder scrap. The present work studied pretreatment for reuse of solder scrap alloys. An experiment was conducted to enhance the cleanliness of solder scrap melt and eliminate impurities, especially lead. Physical separation with sieving and magnetic force was made along with pyrometallurgical methods. A small decrease in lead concentration was found by high temperature treatment of solder scrap melt. The impurities were removed by filtration of the solder scrap melt, which resulted in improvement of the melt cleanliness. A very low concentration of lead was achieved by a zone melting treatment with repeated passage. This study reports on a pretreatment process for the reuse of solder scrap that is lead free.

• Resources Recycling
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• v.28 no.3
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• pp.3-14
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• 2019

Copper is one of the first metals utilized by humankind about 11,500 years ago. But copper is not plentiful metallic element in the earth's crust. Copper has a high thermal and electric conductivity and is relatively corrosion resistant. In principle copper is virtually 100 % recyclable as an element without loss of quality. The recycling of copper scrap reduces the energy consumption and environmental burden, comparing to the primary metal production. Currently, approximately 30% of the global copper supply provides by recycling. Copper scrap is smelted in primary and secondary smelter. Type of furnace and process steps depend on the quality and grade of scrap. Depending on copper content of the secondary raw material, refining is required, which is usually done through electrorefining. This work provides an overview of the primary copper production and recycling process.