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Search Results: 1 - 10 of 747 matches for " Recycling "
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Performance of Green Aggregate Produced by Recycling Demolition Construction Wastes (Case Study of Tanta City)  [PDF]
Alaa El-Din M. Sharkawi, Slah El-Din M. Almofty, Eng. Shady M. Abbass
Engineering (ENG) , 2016, DOI: 10.4236/eng.2016.82006
Abstract: Egypt has a high attitude in construction and demolition waste (CDW) amounts causing a negative impact on the environment. The use of such waste for infrastructures applications can be useful for each environment and in addition an economic benefit to it in the construction. This study explores the possibility of replacing natural coarse aggregate with recycled concrete construction and demolition waste aggregate for general purpose concrete (i.e. plain concrete and low strength structural concrete). Different samples of CDW were extracted from different demolition sites and landfill locations around Tanta city area for the experimental investigation. CDW was crushed with all its hard constituents (e.g. concrete, brick etc.) found in the landfill. Coarse size crushed CDW was used as a coarse aggregate for concrete. Main characteristics of CDW aggregate determined in addition to the main properties of concrete which was made using this aggregate were measured. The results showed that the CDW could be transformed into recycled concrete aggregate leading to reduction in the concrete compressive strength ranged from 37% to 62% depending on the type of the CDW constituents.
Ceramic Tiles Obtained from Clay Mixtures with the Addition of Diverse Metallurgical Wastes  [PDF]
Nancy Quaranta, Marta Caligaris, Miguel Unsen, Hugo López, Gisela Pelozo, Juan Pasquini, Carlos Vieira
Journal of Materials Science and Chemical Engineering (MSCE) , 2014, DOI: 10.4236/msce.2014.22001

The generation of industrial residues is unavoidable, but these materials may be recovered, redirecting them toward new production processes, rather than allocating them to the stream of discards. The aim of this paper is to study the feasibility of utilization of metallurgical wastes as raw material for tiles in the ceramic industry, using the residual materials as aggregates in clay based ceramics. The residues used are: sludge and slag from several metallurgical processes, Ruthner dust and foundry sand. Samples were obtained from mixtures of clay and each waste in various percentages, which were then heat treated. The pieces obtained were characterized using several techniques, with the aim of determining the properties of these materials in relation to the commercial requirements. A high feasibility of reuse of most of these wastes as raw material in the production of ceramic bodies has been established.

Modelling Recycling Targets: Achieving a 50% Recycling Rate for Household Waste in Denmark  [PDF]
Amanda Louise Hill, Ole Leinikka Dall, Frits M?ller Andersen
Journal of Environmental Protection (JEP) , 2014, DOI: 10.4236/jep.2014.57064

Within the European Union (EU) a paradigm shift is currently occurring in the waste sector, where EU waste directives and national waste strategies are placing emphasis on resource efficiency and recycling targets. The most recent Danish resource strategy calculates a national recycling rate of 22% for household waste, and sets an ambitious goal of a 50% recycling rate by 2020. This study integrates the recycling target into the FRIDA model to project how much waste and from which streams should be diverted from incineration to recycling in order to achieve the target. Furthermore, it discusses how the existing technological, organizational and legislative frameworks may affect recycling activities. The results of the analysis show that with current best practice recycling rates, the 50% recycling rate cannot be reached without recycling of household biowaste. It also shows that all Danish municipalities will need to make efforts to recover all recyclable fractions, and that the increased recycling efforts of only selected municipalities will not be sufficient to reach the target.

A Robust Indicator for Promoting Circular Economy through Recycling  [PDF]
Francesco Di Maio, Peter Carlo Rem
Journal of Environmental Protection (JEP) , 2015, DOI: 10.4236/jep.2015.610096
Abstract: In order to move towards a more sustainable development, it is necessary not only to minimize the use of materials in the design stage and to find new materials as alternatives to nonrenewable ones (e.g. optical fiber instead of copper, biopolymers instead of polymers from oil) but also to reclaim as much as possible material value through effective recycling. To this extent, recycling can play a key role in multiple dimensions, while providing new business opportunities for innovative companies, having positive impacts on the society and the environment and fostering an effective circular economy as well. Because of the advanced waste management infrastructures available in developed countries, it is possible to achieve an almost complete collection of solid wastes into a variety of controlled bulk material flows. However, the picture for the follow-up step, the recycling of raw materials such as steel, non-ferrous metals, polymers and glass from these flows, is less positive. Materials value recovered from waste represents a very small fraction of European GDP. The fundamental issue is that policymakers still lack an effective key performance indicator for stimulating the recycling industry. Therefore although recycling plays an important role in the circular economy perspective, it is necessary to radically change the metric used so far to compute the recycling rate. Nowadays, the recycling rate is computed measuring the amount of material entering the recycling facilities. This approach has brought about an inaccurate and somehow misleading indicator (the recycling rate) which contributed to wrong decision making and to poor innovation in the industry. The new approach proposed in this paper considers the use of a Circular Economy Index (CEI) as the ratio of the material value produced by the recycler (market value) by the intrinsic material value1 entering the recycling facility. It is argued that this index is related to strategic, economic and environmental aspects of recycling and it has very important implications as decision making tool. To compute the CEI it is necessary to know detailed information of the components and materials contained in each end of life (EOL) product entering the recycling facilities and how they end up in the recycled raw materials. Therefore an accurate accounting of materials (with standards if available), mass, chemical composition and smallest dimension (e.g. a screw, a plastic foil) is proposed.
Study on the Recycling and Treatment of WEEE in China  [PDF]
Bibo Yang, Renxia Chen
American Journal of Operations Research (AJOR) , 2012, DOI: 10.4236/ajor.2012.23033
Abstract: This paper investigates the regulations, recycling and treatment of WEEE (waste electrical and electronic equipment) in China. An online survey about Chinese households’ treatment of WEEE is conducted. Optimization models are used to compare the performances of WEEE treatment in two different recycling networks. In the first network, WEEE is collected and sent by recycling stations to licensed WEEE recycling and treatment centers for testing and dismantling. In the second network, WEEE are tested and dismantled at small recycling workshops in residential districts, and then parts/components that require further processing are sent to licensed WEEE recycling and treatment centers. The performances of the two networks are analyzed with linear programming models. The results indicate that the second model is more effective with lower cost and higher recycling efficiency.
PET Oligomer Waste to Modify CAP Characteristics  [PDF]
L. C. Mendes, M. L. Dias, P. S. C. Pereira, L. M. R. Albuquerque
Materials Sciences and Applications (MSA) , 2012, DOI: 10.4236/msa.2012.38082
Abstract: To develop an improved method of reusing poly(ethylene terephthalate) (PET) waste in the production chain, it was chemically modified with pentaerythritol (PENTE), resulting in PET/PENTE (60/40) oligomer. This was added to petroleum asphalt cement (CAP) in different proportions—5, 10 and 20 wt%—as a modifier of bitumen characteristics. The mixture was evaluated by thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), optical microscopy (OM) and the adhesion-peel test. The oligomer enhanced substantially the asphalt thermal stability-Tonset. OM images showed strong compatibility between components and PET’s amorphization. PET oligomer increased CAP’s wettability and the mixture presented cohesive fracture through the peel test. The mixture has excellent potential as paving material.
Use of Coal Waste as Fine Aggregates in Concrete Paving Blocks  [PDF]
Cassiano Rossi dos Santos, Juarez Ramos do Amaral Filho, Rejane Maria Candiota Tubino, Ivo André Homrich Schneider
Geomaterials (GM) , 2013, DOI: 10.4236/gm.2013.32007

The aim of this work was to study the use of coal waste to produce concrete paving blocks. The methodology considered the following steps: sampling of a coal mining waste; gravity separation of the fraction with specific gravity between 2.4 and 2.8; comminution of the material and particle size analysis; technological characterization of the material and the production of concrete paving blocks. The results showed that the coal waste considered in this work can be used to replace conventional sand as a fine aggregate for concrete paving blocks. This practice can collaborate in a cleaner coal production.

Studying the Utilization of Plastic Waste by Chemical Recycling Method  [PDF]
Adil Ko?
Open Journal of Applied Sciences (OJAppS) , 2013, DOI: 10.4236/ojapps.2013.37051

The rapid increase in the use of plastic materials in the recent years led to the accumulation of excessive amounts of plastic waste. The so-called thermoplastics such as PE, PP, PS, PVC and PET as well as materials that are derived from these are the type of plastic that is most used and consequently creates most of the waste. In this study, the original and waste forms of PE and PP plastic types have been chosen for thermal and catalytic degradation. As process parameter, 410oC - 450oC temperature interval and 600 mL/min constant flow rate nitrogen gas have been chosen as the carrier gas and the reaction time was considered to be 90 minutes for all experiments. Liquid products collected in experiments were separated by means of fractioned distillation process. For purposes of determining product distribution, the fractions, which were separated by distillation, were diluted in an appropriate solution for analysis of GC/MS. In the study conducted, it has been observed that the liquid product distribution obtained mainly consists of a mixture of saturated and unsaturated (heptane, heptane, octane, nonane, dodecane, etc.) hydrocarbons.

Cell-Phone Recycling by Solvolysis for Recovery of Metals  [PDF]
Lorena Eugenia Sánchez Cadena, Zeferino Gami?o Arroyo, Mario Alberto González Lara, Q. Demetrio Quiroz
Journal of Materials Science and Chemical Engineering (MSCE) , 2015, DOI: 10.4236/msce.2015.31008

Mobile phones represent a significant and growing problem with respect to electrical waste and electronic equipment (WEEE). Nevertheless, they are perhaps one of the most valuable electronic products, since they are an important resource for the recovery of metals in terms of mass and volume. In this research a chemical recycling of mobile phones by solvolysis was investigated. The processing was performed by comminution in a hammer mill followed by screening to obtain mesh-4 sized flakes. Flakes were subjected to solvolysis. Different reaction conditions were tested. A reaction time between 2 - 7 hours and a temperature between 150°C - 300°C were the optimum conditions to dissolve the polymer contained in mobile phones. Metals were separated by filtration. Chemical analyses (ATR FT-IR, UV) were carried out on the solvent and the mobile phone flakes before and after solvolysis. A SEM study was carried out, before and after solvolysis, but only to the mobile phone flakes. Thermal transitions of mobile phone flakes were determined by DSC. Chemical results showed that some aromatic species migrate from mobile phones flakes to the solvent, due to the solvolysis reaction. Thermal analysis showed that the Tg, (glass transition temperature) of mobile phone flakes after solvolysis was different to Tg of the polymer before solvolysis, this is due to chemical changes in the molecule. A comparative SEM study revealed that, after solvolysis, the polymer contained in mobile phone flakes is more elastomeric. After solvolysis, solvent was recovered by means of a rotatory evaporator, so that it can be used again. The results obtained in this research showed that solvolysis is an alternative for metal recovery from mobile phones.

Recovery of Metals from Aluminum Dross and Saltcake  [PDF]
J.Y. Hwang, X. Huang, Z. Xu
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2006, DOI: 10.4236/jmmce.2006.51003
Abstract: Various aluminum-smelting by-products from three production sources were received and characterized. The waste materials were tested for compound identification and environmental acceptance. A coarse metallic aluminum recovery test using an Eddy Current separator (ECS) was performed using two different Circuit configurations. White dross performed equally well with either Circuit, while black dross processing shows significant difference on the separation results. It was found that ECS technology was effective for particle sizes down to 6-10 mesh.
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