Recovery Of Raw Materials Research Articles

Biotechnological Tool for Metal(loid)s as Cd, Cu, Ni, and P Management with Multiple Approaches: Bioremediation, Recovery of Raw Materials, and Food Safety

Contaminated soils are a challenge for implementing biotechnology in bioremediation, the recovery of Critical and Strategic Raw Materials (CRMs and SRMs), and food security. European Union (EU) Governments have established strict limits on As, Pb, Cd, and Hg in foods (Document 32023R0915) and requested the recovery of 34 CRMs within a circular economy (CE) (5th CRMs list). This study proposed a biotechnological tool for the decontamination of soil with heavy metal(loid)s by arbuscular mycorrhizal (AM)-assisted phytoextraction and the subsequent recovery of CRMs or by phytostabilization to prevent their entry into the food chain. It consisted of placing Baccharis salicifolia plants, inoculated or non-inoculated with AM fungi, into bioreactors (BRs) containing mining soil with Cd, Ni, and Cu, according to the Argentinian Patent (AR090183B1). The bioextractive potential (BP) was also estimated at the highest Technological Readiness Level (TRL) using a vegetable depuration module (VDM, TRL 6). Inoculated plants showed significantly higher aerial bioaccumulation coefficients (Cd: 68.62; P: 2.99; Ni: 2.51; Cu: 0.18) in BRs, and the BP values reached 1.16 g, 9.75 g, 2.40 g, and 213.1 g for Ni, Cd, Cu, and P, respectively. Finally, these CRMs and SRMs could be recovered from biomass through hydrometallurgy within a CE framework.

Scenario analysis of waste tires from China's vehicles future

As a byproduct of vehicles, tires are utilized in large quantities with the widespread promotion of vehicles. Long-term accumulation of non-degradable waste tires occupies land resources and poses severe environmental threats. Projecting future waste tire volumes provides a scientific basis for preventing excessive accumulation, enables proactive planning of recycling strategies, reduces environmental pollution and promotes waste tire recycling. Using a bottom-up Road Transport Waste Tire Stock model, this study projects vehicle stocks and corresponding annual increases in waste tires from 2002 to 2050. The study reveals that China's vehicle and waste tire stock follows an S-curve growth. Vehicle ownership is projected to increase from 276 million in 2020 to 490–583 million by 2050. Between 2002 and 2030, waste tire generation from vehicles is expected to rise from 4.79 million tons to 18.13–18.57 million tons. By 2050, growth will slow, but the total output will still reach 18.90–19.85 million tons, with cargo trucks contributing 68%. By 2050, Shandong is the leading province in waste tire production, generating 1.82 million tons annually, accounting for 9.1%. Hainan will see the highest growth rate by 2030, with a 40% increase from 2020 levels. The study, based on current policies, presents three recommendations: improving waste tire tracking and recycling systems, implementing region-specific management strategies, and promoting the resource recovery of raw materials from cargo trucks waste tires. These measures aim to enhance waste tire management and foster rubber resource recycling.

Low-Temperature Carbothermic Reduction for Recycling LiCoO2 for the Recovery of Critical Raw Materials: The Role of Cellulose

Low-Temperature Carbothermic Reduction for Recycling LiCoO₂ for the Recovery of Critical Raw Materials: The Role of Cellulose

(Invited) Solvometallurgy as a Sustainable Approach for Lithium-Ion Batteries Recycling

Lithium-Ion Batteries, LIBs, are the core devices that made possible the diffusion of portable consumer electronics and, more recently, the booming of the electric vehicle market. [1] Their ubiquitous use and diffusion led to the well-known and urgent problem of spent LIBs management. Indeed, spent LIBs represent a complex and hazardous kind of waste for which specific regulation, disposal, and recycling routes are still missing. At the same time the continuous and growing production of LIBs involves the mandatory use of specific elements such as Li, Co, Ni, Cu, Al that are considered strategic or critical raw materials due to their limited availability, high costs, monopoly, and geological distribution. [2] The development of efficient and sustainable procedures for recycling of spent LIBs is the answer to these two main challenges as in enable to properly manage the LIBs waste and allow for the recovery of critical raw materials. While at industrial scale the high temperature pyrometallurgy and hydrometallurgy are the methods in use today, in the very last years, many approaches have been explored at research level, among them low temperature pyrometallurgy, soft hydrometallurgy, solvometallurgy, bioleaching. [3] Among them, the solvometallurgical approach exploiting Deep Eutectic Solvents (DESs) as leaching agents is particularly appealing thank to some specific features such as the low volatility, low flammability, low costs, ease of preparation combined with high leaching efficiencies.DESs are mixture of based on the presence of a hydrogen bond donors and acceptors forming a eutectic mixture at ambient temperature; although their first conceptualization is recent, several compositions have been already appeared in literature for this specific application. [4] At the same time, a rationalization of the role of the mixture components and a specific design of the composition, tailored for the application in LIBs recycling is still missing. We here present the results of our work on the development of new DESs compositions enabling the close-loop recycling of different spent cathodes. The DES compositions have been designed considering the overall recycling process, the effect of the DES compositions in terms of hydrogen bond donors and acceptors has been evaluated and rationalized through a preliminary chemical-physical characterization through thermal, NMR, FTIR, viscosity analysis. The leaching of the most common cathode has been optimized against the dominant parameters (temperature, treatment duration, cathode-to-DES ratio) opening the ways for two possibilities: the recovery of critical raw materials and the direct resynthesis of new cathodes. All the steps and products have been fully characterized with a multi-technique approach including structural and chemical investigation through the electrochemical testing of the re-synthetized materials. Finally, these two options have been assessed through LCA analysis, being able to provide an overview of the global sustainability of the proposed processes.[1] Ji et al., Chem Soc. Rev. (2023) doi 10.1039/d3cs00254c[2] Global Supply Chains of EV Batteries report, International Energy Agency[3] Yasa et al. J. En. Stor. 73 (2023) 109073[4] Padwal et al. Adv. En. Sus. Res. 3 (2022) 2100133

The Application of Atomic Spectroscopy Techniques in the Recovery of Critical Raw Materials from Industrial Waste Streams, Part II

This month’s column is Part 2 of a contribution from my daughter Glenna, who recently completed her PhD studies in Environmental Science from the University of Copenhagen in Denmark. Her article explores the current landscape of global critical raw materials (CRM) trends in research and the applications of atomic spectroscopy (AS), including inductively coupled plasma–mass spectrometry (ICP-MS), inductively coupled plasma–optical emission spectrometry (ICP-OES), and X-ray analytical techniques in their identification of diverse industrial and environmental media, which have been essential in method validation and quantification of CRMs in complex matrices presenting high risks of interference. Some important examples to be presented include rare earth elements (REEs) in water leaching purification (WLP) residues that co-occur with radioactive materials; REEs and other metals in acid mine drainage (AMD) environments; REEs in coal combustion (fly ash) residues; arsenic (As) from groundwater treatment sediment; and platinum-group elements (PGEs) from sewage sludge. The article also classifies the different techniques in use at each stage of the CRM recovery train, investigates present challenges to each analytical method, and discusses the problem-solving tools used.

The Application of Atomic Spectroscopy Techniques in the Recovery of Critical Raw Materials from Industrial Waste Streams, Part I

This month’s column is a contribution from my daughter Glenna, who recently completed her PhD studies in environmental science from the University of Copenhagen in Denmark. Her article explores the current landscape of global critical raw materials (CRM) trends in research and the applications of atomic spectroscopy (AS), including inductively coupled plasma–mass spectrometry (ICP–MS), inductively coupled plasma–optical emission spectrometry (ICP–OES), and X-ray analytical techniques in their identification of diverse industrial and environmental media, which have been essential in method validation and quantification of CRMs in complex matrices presenting high risks of interference. Some important examples that are presented include rare earth elements (REE) in water leaching purification (WLP) residues that co-occur with radio- active materials, REEs and other metals in acid mine drainage (AMD) environments, REEs in coal combustion (fly ash) residues, arsenic (As) from groundwater treatment sediment, and platinum-group elements (PGE) from sewage sludge. In addition, the article classifies the different techniques in use at each stage of the CRM recovery train, investigate present challenges to each analytical method, and discuss the problem-solving tools used.

Techno-economic evaluation of antimony and bismuth upcycling from pyrometallurgical copper wastes

The recovery of critical raw materials (CRMs) is important to reduce the supply risk disruption and the dependency on third-countries within the European Union (EU). The present study evaluates the techno-economic implications of antimony (Sb) and bismuth (Bi) recovery from the process stream produced in the polishing stages of the copper electrorefining circuit. The upcycling process was based on the selective precipitation of Sb and Bi from the concentrated hydrochloric acid (HCl) (up to 5–6 M) process stream containing high arsenic (As) concentrations. Four different scenarios were included in the evaluation, in which Sb and Bi were recovered as Sb4O5Cl2(s)/Sb2O3(s) and BiOCl(s)/Bi2O3(s), respectively. The results showed that implementing Bi and Sb upcycling configurations in the copper metallurgical facilities was economically feasible when recovering BiOCl(s)/Sb4O5Cl2(s) and BiOCl(s)/Sb2O3(s) from the eluate stream. Sb recovery was the most cost-intensive process in all the configurations evaluated due to the high chemical requirements needed to neutralize the free HCl excess. The consumption of chemicals represented the most important cost contributor, since high amounts of chemicals are needed for the selective Sb and Bi precipitation. The sensitivity analysis illustrated that recovering these CRMs was economically attractive for all the configurations when achieving Sb and Bi prices above 8.5 and 9.5 €/kg, respectively. Under these CRM prices, the payback period and internal rate of return for the different scenarios range from 4 to 19 years and from 6 to 28 %, respectively. This output highlights that future increase in CRM prices can be an important driver to implement Sb and Bi recovery schemes. Overall, the results of this study highlight the economic potential of implementing Sb and Bi recovery schemes in copper metallurgical plants to align with the ambitious circular economy objectives established by the EU.

Modelling Binder Degradation in the Thermal Treatment of Spent Lithium-Ion Batteries by Coupling Discrete Element Method and Isoconversional Kinetics

Developing efficient recycling processes with high recycling quotas for the recovery of graphite and other critical raw materials contained in LIBs is essential and prudent. This action holds the potential to substantially diminish the supply risk of raw materials for LIBs and enhance the sustainability of their production. An essential processing step in LIB recycling involves the thermal treatment of black mass to degrade the binder. This step is crucial as it enhances the recycling efficiency in subsequent processes, such as flotation and leaching-based processing. Therefore, this paper introduces a Representative Black Mass Model (RBMM) and develops a computational framework for the simulation of the thermal degradation of polymer-based binders in black mass (BM). The models utilize the discrete element method (DEM) with a coarse-graining (CG) scheme and the isoconversional method to predict binder degradation and the required heat. Thermogravimetric analysis (TGA) of the binder polyvinylidene fluoride (PVDF) is utilized to determine the model parameters. The model simulates a specific thermal treatment case on a laboratory scale and investigates the relationship between the scale factor and heating rate. The findings reveal that, for a particular BM system, a scaling factor of 100 regarding the particle diameter is applicable within a heating rate range of 2 to 22 K/min.

Phytoextraction Options.

Wastewaters often contain an array of economically valuable elements, including elements considered critical raw materials and elements for fertilizer production. Plant-based treatment approaches in constructed wetlands, open ponds, or hydroponic systems represent an eco-friendly and economical way to remove potentially toxic metal(loid)s from wastewater (phytoextraction). Concomitantly, the element-enriched biomass represents an important secondary raw material for bioenergy generation and the recovery of raw materials from the harvested plant biomass (phytomining). At present, phytoextraction in constructed wetlands is still considered a nascent technology that still requires more fundamental and applied research before it can be commercially applied. This chapter discusses the different roles of plants in constructed wetlands during the phytoextraction of economically valuable elements. It sheds light on the utilization of plant biomass in the recovery of raw materials from wastewater streams. Here, we consider phytoextraction of the commonly studied water pollutants (N, P, Zn, Cd, Pb, Cr) and expand this concept to a group of rather exotic metal(loid)s (Ge, REE, PGM) highlighting the role of phytoextraction in the face of climate change and finite resources of high-tech metals.

Study on the process of producing crotonaldehyde from acetaldehyde catalyzed by Zr-β zeolite

As an essential raw material of chemical industry, crotonaldehyde is mainly used to produce sorbic acid, which is a kind of safe food preservative. The nowadays production process of crotonaldehyde adopts sodium hydroxide solution and acetic acid in series as catalysis, which cause serious problems such as salinity waste water and equipment corrosion. Therefore, Zr-β zeolite was developed to catalyze the production of crotonaldehyde from acetaldehyde gas–solid reaction process in our group. This catalyst showed the potential of industrial application for its 94 % selectivity and stability. This paper aims to develop a technological process to produce crotonaldehyde from acetaldehyde based on the newely-researched-out Zr-β zeolite catalyst. According to experimental results of reaction condition and product distribution, a technological process consisting of (1) aldol condensation reaction and raw material recovery section, (2) crotonaldehyde concentration and refinement section, (3) 2-methyl-2-cyclopenten-1-one (MCP) and acidic impurity removal section was established. Mechanical supercharging was employed in section (1) to elevate the heat grade of reactor effluent to heat the reactor feed. Pre-concentration followed by azeotropic distillation was proposed to purify croton aldehyde product. The removal of little MCP in the re-used water was accomplished by evaporating MCP at the top of the column based on our previous finding that MCP-water could form minimum azeotrope. As a result, the purity of crotonaldehyde reached 99.92 wt% and water content reduced below 10 ppm in product, which is much better than the product standard required crotonaldehyde purity 99.5 % and water content 2000 ppm. Based on optimum process, heat exchange network was further optimized with pitch point method, and at last the required heat load was 2.25 Gcal per ton of crotonaldehyde product. The problem of generating salinity waste water in the traditional process was solved thoroughly, which meant that this is a more environmentally friendly process to produce crotonaldehyde.

Management of selected waste generated during cable production

The subject of the research was the recovery of raw materials from waste generated in the production of cable insulation and the management of aluminum sludge. It was found that 49% (w/w) acetophenone, 6.8% (w/w) α-methylstyrene, and 17.2% (w/w) cumyl alcohol can be recovered from waste with a loss on ignition of 95% and used in various industries. A gas chromatograph equipped with a mass spectrometry detector was used to identify the recovered compounds. A waste distillation process was proposed to remove the water layer and obtain a concentrated acetophenone fraction. A method of neutralizing the water fraction and distillation residues is presented. The proposed waste management method is an alternative method to the currently used thermal transformation method. In turn, aluminum sludge was used to produce aluminum sulfate, which was used in the plant’s sewage treatment plant as a coagulant. The effect of this action was a reduction of 67% in the content of total iron, 60% of trivalent iron, and 32% of chemical oxygen demand. The above-mentioned examples of waste management are part of a closed-loop waste management strategy.

Use of Recycled Polyethylene in Asphalt Mixture

Abstract Plastics and plastic products have become part of our lives extremely quickly. Although, they make our lives easier in many aspects, at the end of their useful life, especially thanks to the thoughtless actions of people, they are becoming a serious environmental problem. Even though the laws and legislation are still forcing limits of using the plastic products and thus prevent waste, the concept of plastic-free living is probably not going to be reached easily and quickly. Using the recycling technology, we can prepare the recycled material, which represents a new raw material resource. With the right choice of physical-chemical parameters of recycled materials and using a suitable reaction condition we can incorporate them into the asphalt mixtures. Since their introduction the polymer-modified asphalt mixtures have gained in importance during the second half of the twentieth century, and they now play a fundamental role in the field of road paving. Moreover, the use of recycled plastic in such a product will contribute to the technical and economic recovery of secondary raw materials. The use of various recycled material in paving industry is a common practice but needs further research work. Thus, this study aims to the incorporation of recycled plastics into asphalt mixture. The main objective of our work was to find a suitable recycled plastic, which with its physico-chemical and technical parameters is suitable for incorporation into the asphalt mixture. In our study the recycled low-density polyethylene granulate was used, taken from films and various packaging materials. Our preliminary laboratory experiments were based on the possibilities to prepare and characterized the asphalt mixtures containing recycled plastic at different percentage, i.e., 4 %, 6 %, 8 % and 10 % by weight of bitumen. The experimental tests performed in the study were bitumen content, intergranularity, maximum bulk density, water sensitivity and resistance to permanent deformations. The results showed that the mix containing 6 % by weight of recycled plastic has ideal properties and meets most of the criteria that have been set for asphalt mixes. A commercially available polymer of similar chemical composition to the recycled material was used as a reference sample.

Phenolic Composition of Red and White Wine Byproducts from Different Grapevine Cultivars from La Rioja (Spain) and How This Is Affected by the Winemaking Process.

The recovery of raw materials offers an opportunity for applying the principles of circular bioeconomy. The phenolic composition of three underused wine byproducts (skin, seed, and bunch stem) was analyzed through UHPLC-QqQ-MS/MS to evaluate the intercultivar variability comparing red and white grape cultivars from La Rioja (Spain) and the influence of the winemaking, comparing conventional fermentation and carbonic maceration. We observed that the red skin, especially from Graciano, is rich in anthocyanins, whereas the white skin contains mainly phenolic acids, flavonols, and flavan-3-ols, with Maturana Blanca being the richest variety. Seeds are rich in flavan-3-ols and lignans with Maturana Blanca and Viura, respectively, the richest cultivars. Stems contain high amounts of flavan-3-ols, lignans, and stilbenes, with the red cultivars of Garnacha and Tempranillo being the richest samples. Carbonic maceration has a negative effect on the phenolic amount compared to conventional fermentation. In synthesis, we observed that each type of byproduct from red or white grape cultivars has a particular phenolic composition that can result in obtaining different ingredients with particular phenolic composition for target applications.

Social acceptance, emissions analysis and potential applications of paper-waste briquettes in Andean areas

The research assessed waste-based briquettes consumption compared to conventional fuels in the Andes. Laboratory tests were conducted together with on-field analysis in Colquencha (Bolivia). The laboratory study shows that the performances of briquettes are better in terms of PM2.5 (933.4 ± 50.8 mg kg−1) and CO emissions (22.89 ± 2.40 g kg−1) compared to animal dung (6265.7 ± 1273.5 mgPM2.5 kg−1 and 48.10 ± 12.50 gCO kg−1), although the boiling time increased due to the lower fuel consumption rate and firepower compared to shrubs. The social survey organized with 150 Bolivian citizens suggested that low-income households are not able to pay for an alternative fuel: about 40% would pay less than 4 USD per month, while methane use for cooking is positively correlated with the income level (r = 0.244, p < 0.05). On field analysis suggested that local cookstoves are not appropriate for briquettes combustion since indoor air pollution overcomes 30 ppm of CO and 10 mgPM2.5 m-3. On balance, local small manufactures can be the main target for selling waste-based briquettes to reduce shrubs and wood consumption. However, briquettes production costs seem not yet competitive to natural easy-to-obtain fuels (i.e., animal dung). The research encourages the use of cellulosic and biomass waste-based briquettes in the Andean area for cooking, heating, or manufacturing and strongly advises policy-makers to introduce economic incentives for the recovery of secondary raw materials.

Design and operation of a packed pilot scale distillation column for tire pyrolysis oil: Towards the recovery of value-added raw materials

This work describes the key features involved in the design and operation of a pilot scale distillation column for the recovery of value-added products from tire pyrolysis oil (TPO), as part of the BLACKCYCLE project. The distillation unit was designed using engineering heuristic rules, simulated distillation (SimDist) data and Aspen Hysys ® modeling. The distillation plant consists of a packed column with a nominal throughput of 20 kg/h, and is classified at the fifth technology readiness level (TRL-5). The commissioning and results of long-term experimental campaigns for validation purposes are also presented. In this way, important information is gathered for the design of larger plants. The distillation unit was tested and validated using TPO produced from a pilot scale continuous single-auger pyrolysis plant. A first distillation was performed yielding a heavy fraction (HF-1) with properties suitable for carbon black production, while the light fraction (LF-1) includes the presence of value-added chemicals such as benzene, toluene, ethylbenzene and xylenes (BTEX) and limonene. The LF-1 was also used for a second distillation, producing a stream high in limonene at the bottom (HF-2), and another one high in BTEX compounds at the top (LF-2), which are valuable raw materials for polymer production and petrochemicals, respectively. The key results obtained here are expected to provide an outstanding impetus for the circular economy of complex streams such as end-of-life tires (ELTs) by combining pyrolysis and distillation technologies.

Separation process and mechanism of cyclohexane/ethanol system using deep eutectic solvents based on betaine and choline chloride

The efficient separation of azeotropes is of great significance for the effective recovery and utilization of chemical raw materials and environmental protection. This study investigated the separation efficiency and mechanism of deep eutectic solvents (DESs) with different combinations and ratios of hydrogen bond acceptors (HBA) and hydrogen bond donors (HBD) for cyclohexane/ethanol azeotropic systems. Through vapor-liquid phase equilibrium experiments, the effects of different DESs and different HBD: HBA molar ratios as solvents on the phase behavior of cyclohexane/ethanol azeotropic system were studied, and different combinations and molar ratios of DESs with the best separation performance were obtained. The effective separation of azeotropes by DESs is primarily due to the stronger molecular surface electrostatic potential of ethanol compared to that of cyclohexane, which results in a stronger interaction between the DESs and ethanol. Finally, through process simulations, a cyclohexane/ethanol extractive distillation separation process using a DES as the main solvent was established. The results showed that the separation effect of DESs increased with the increase of the interaction force between DESs and ethanol, achieving efficient recovery of chemical raw materials. This study established a safe and efficient separation process using DESs, which is of great significance for environmental protection and the development of safety processes.

Microwave-Assisted Recovery of Spent LiCoO2 Battery from the Corresponding Black Mass

The literature indicates that utilizing pyrometallurgical methods for processing spent LiCoO2 (LCO) batteries can lead to cobalt recovery in the forms of Co3O4, CoO, and Co, while lithium can be retrieved as Li2O or Li2CO3. However, the technology’s high energy consumption has also been noted as a challenge in this recovery process. Recently, an innovative and sustainable approach using microwave (MW) radiation has been proposed as an alternative to traditional pyrometallurgical methods for treating used lithium-ion batteries (LiBs). This method aims to address the shortcomings of the conventional approach. In this study, the treatment of the black mass (BM) from spent LCO batteries is explored for the first time using MW–materials interaction under an air atmosphere. The research reveals that the process can trigger carbothermic reactions. However, MW makes the BM so reactive that it causes rapid heating of the sample in a few minutes, also posing a fire risk. This paper presents and discusses the benefits and potential hazards associated with this novel technology for the recovery of spent LCO batteries and gives information about real samples of BM. The work opens the possibility of using a microwave for raw material recovery in spent LIBs, allowing to obtain rapid and more efficient reactions.

Ni-WC/Al2O3 and Ni-WC/MgWO4/MgAl2O4 catalysts for resource recovery via pyrolysis combined with the dry reforming of plastics (PCDR)

Plastic waste (PW) is currently one of an environmental threat. Despite the increasing share of recycled plastics, their disposal remains high. Therefore, there is a high demand for new PW management systems. Among them, pyrolysis combined with dry reforming (PCDR) is an advantageous solution because it allows for resource recovery in the form of gas and liquid fuels, with simultaneous utilization of CO2. To date, catalysts based on Ni, Co, and noble metals supported on metal oxides have been examined. However, these catalysts suffer from quick deactivation due to coking and sintering. Therefore, testing other materials for PCDR is of particular importance. In this regard, Ni-WC/Al2O3 and Ni-WC/MgWO4/MgAl2O4 were investigated as potential PCDR catalysts. The catalysts were characterized by BET, BJH, XRD, CO2-TPD, H2-TPR, SEM, TEM, TG and DTG. The catalytic activity was evaluated in a two-step PCDR process using low-density polyethylene (LDPE), polystyrene (PS), polyethylene terephthalate (PET), and simulated waste plastic (SWP). The structure of the polymer strongly determines the yields of gas, liquid, and solid products. The highest yield of synthetic gas generation was observed for Ni-WC/MgWO4/MgAl2O4 and was 48.20 ± 2.41 mmol/gp. Different origins of the structural changes including oxidation or coking were observed for different plastics. PCDR of PET led mainly to oxidation, LDPE to the coking deposition. Catalysts after the process with PS were characterized by preservation of crystalline structure. The results indicate a high potential of carbide catalysts in the recovery of gaseous and liquid raw materials.

Evaluation of the effect of physical and chemical factors in the recovery of Cu, Pb and Fe from waste PCB through acid leaching

Electronic waste recycling is a strategy that contributes to implement a circular economy model which include reuse, component and raw material recovery and minimum final deposition. Given the importance of reincorporating the components of electronic devices into the productive chain and a correct recovery for some hazardous metals such as lead contained in such residues. This study is focused on the effect of maximum available content (MAC) of metal, sulfuric acid initial concentration, agitation velocity, and oxidising agent on the recovery of copper, lead and iron from electronic waste through acid leaching. A solid-state characterization before and after treatment and electrochemical analysis was carried out to analyse MCA effects and surface chemistry. It was found that sub-millimetric particles show a better available extraction percentage in case of copper and iron, being opposite for lead. Presence of hydrogen peroxide enhance the extraction efficiency, however, this cause iron and lead precipitation, therefore it is inefficient for metals recovery as well as for reagent consumption. The presence of calcium salts reacts producing gypsum, which reduces the extraction yield of copper at particle size below 250 μm.

Supply chain design and planning for the carpet industry considering recycling processes

This paper introduces a mixed-integer linear programming model to tackle the design and planning problem of Closed Loop Supply Chains in the carpet industry. A distinctive feature of the approach is handling different recovery processes involving dissimilar activities and flows of recovered materials. Moreover, the reverse network facilities and logistics are completely integrated with the forward network structure, in order to obtain a high level of customer supply while considering economic goals. In addition, the economies of scale for the recycling facilities are also explicitly handled. The model allows to determine the products and quantities to be manufactured, transported, stored, and recycled to cover the demand of a set of customers. The objective function is to maximize the profit of the whole life-cycle of products. An example based on an industrial case that involves the recovery of raw materials is presented to show the relevance of the method.