Eddy Current Separation Research Articles

Simulation of Eddy Current and Repulsive Force of Non-Ferrous Particles in Eddy Current Separator

Simulation of Eddy Current and Repulsive Force of Non-Ferrous Particles in Eddy Current Separator

QUALITY ASSESSMENT OF NONFERROUS METALS RECOVERED FROM LANDFILL MINING: A CASE STUDY IN BELGIUM

Nonferrous metals (NFM) contribute the most to the revenues that might be generated by the implementation of landfill mining (LFM). However, metals in landfills undergo stronger degradation compared to that of their normal use, which might lead to a lower scrap quality compared to conventional scrap. Nowadays, there is information about the most common metals found in LFM, but no reliable data about their quality. In general, excavated landfill material is processed mechanically through different steps, such as particle size separation and metal classification by magnetic and eddy current separation. The subject of this work is the characterisation of NFM recovered from a landfill in Belgium with the goal to assess the quality of metals for marketing purposes. In this study, two questions about the real concentration of metals and the marketability of NFM are discussed. A primary evaluation shows that there is around 5 kg of NFM per ton of excavated material processed at the Mont-Saint-Guibert landfill. Besides, through thermal treatment, it was possible to find out that on average only 70 wt% of the NFM is metallic being the rest, defilements (30 wt%) strongly attached. As a result, a technical assessment was carried out following two approaches. In the first approach, 7 types of scraps can be potentially recovered from NFM: two different qualities of Al scrap, two of Cu, one of Pb, one of Zn, and one of stainless steel. In the second approach, NFM might be commercialised directly from the landfill as a mixed nonferrous scrap.

Linear Circuit Analysis: a Tool for Addressing Challenges and Identifying Opportunities in Process Circuit Design

One of the most important processing engineering tools for designing mineral processing facilities is linear circuit analysis. This technique, originally conceived and developed by Meloy, Williams, and Fuerstenau nearly four decades ago, provides fundamental insights regarding how unit operations interact and respond when arranged in multi-stage processing circuits. Researchers have successfully utilized this tool to improve the operating performance of industrial processing circuits incorporating coal spirals, magnetic separators, mineral spirals, and eddy current separators. More recently, advanced versions of this tool have also been developed to provide a standardized framework for circuit mass balance calculations, to output exact analytical solutions to mass yield and value-based efficiency expressions, and to estimate uncertainty propagation in separation circuits. This article reviews the historical development of linear circuit analysis, describes how the technique has evolved to address more complex circuit design problems, and presents industrial case studies that highlight the importance of this process engineering tool.

Direct Transformation of Metallized Paper into Al-Si Nano-Rod and Al Nano-Particles Using Thermal Micronizing Technique

The abundant application of metallized paper and the quick growth of their wastes lead to the removal of a huge amount of valuable resources from economic cycle. In this work, for the first-time, the thermal micronizing technique has been used to directly transform the metallized paper wastes to Al-Si nano-rod and Al nano-particles for use as the input in different manufacturing sectors such as additive manufacturing or composite fabrication. Structure of metallized paper has been investigated using FT-IR analysis and first-principle plane-wave calculation. Then, based on the structure of metallized paper, thermal micronizing technique has been modified to directly transform this waste into nano materials. Structure of nano-particles and nano-rods has been investigated using SEM, TEM, and XPS analysis. Results showed two main Al-Si nano-rod and Al nano-particle morphologies created as a result of the different surface tensions, which facilitate their separation by Eddy current separation technique. These quick transformation and facile separation together make this technique a unique process to deal with this complex waste and producing value-added products which can re-capture these high value materials from waste and make the reforming economically viable.

Calculation of the Electromagnetic Repulsion for Eddy Current Separation About the Scrap Copper

Calculation of the Electromagnetic Repulsion for Eddy Current Separation About the Scrap Copper

An analytic model for eddy current separation

Eddy current separation (ECS) is a process used throughout the scrap recycling industry for separating nonferrous metals from nonmetallic fluff. To date, however, the physical theory of ECS has generally been limited to empirical approximations and numerical simulations. We therefore introduce a simplified, two-dimensional model for ECS based on a cylindrical array of permanent, alternating magnets. The result is a Fourier-series expansion that describes the total magnetic field profile over all space. If the magnets are then rotated with constant angular velocity, the magnetic fields vary as a discrete series of sinusoidal harmonics, thereby inducing electrical eddy currents in nearby conductive particles. Force and torque calculations can then be used to predict the corresponding kinematic trajectories.

Developing the combined magnetic, electric and air flow (KLME) separator for RMSW processing.

The authors are working on the development of a mechanical-physical processing plant to prepare non-selectively collected residual municipal solid waste (RMSW) in the Zalaegerszeg region of Hungary. A key element of this processing plant is the newly developed KLME separator (the name KLME is the Hungarian abbreviation of 'combined magnetic, electric and air flow'). This separator is a combination of three widely applied separators, namely a magnetic separator, an eddy current separator and two types of air flow separators designed without the ordinarily necessary cross connecting belt conveyors and feeders. Extensive RMSW and WEEE (waste electrical and electronic equipment) sampling and analyses were carried out in three municipalities to obtain model materials before designing the technology. After fundamental research and laboratory-scale testing, a pilot-scale KLME separator prototype (1.5 ton/h) was made. It has one input stream and five output streams targeted towards five types of products: two-dimensional materials (foils), three-dimensional light materials, magnetic materials, electrically conductive materials and heavy inert materials. Systematic pilot scale testing was carried out and 18 discrete technological setups were tested. The technology as well as the machine were continuously improved and modified based on on-site observations. The best yields and the experience gained are being utilised for the design of an industrial size machine.

Integrated process for recycling aluminum electrolytic capacitors from waste printed circuit boards: Disassembly, heat treatment and magnetic–eddy current–electrostatic separating

An aluminum electrolytic capacitor (AEC), mounted on a printed circuit board (PCB), is an integral part of any electronic product. Currently, a great many waste AECs are generated from almost all kinds of end-of-life electronic products. The waste AEC is hazardous waste because the electrolyte contained in it is toxic, demanding safe disposal. However, the recycling technology has been poorly developed. This article presented a novel attempt to deal with AECs disassembled from waste PCBs, including heat treatment, crushing, and multistage physical separations. Firstly, the electrolyte contained in waste AECs was removed by heat treatment. Secondly, the residue was crushed to liberate metals (aluminum and iron) from nonmetals, and the pins (iron) were magnetically separated from other substances. Thirdly, the remaining components were sieved, and the particles with the particle size >1.6 mm were subjected to eddy current separation, and the particles with the particle size <1.6 mm were subjected to electrostatic separation. Finally, an integrated recycling process was developed based on the above studies. Under the optimum conditions, the total separation efficiency and the grade of aluminum were 87.9% and 98.25%, respectively. This study provides a feasible method for waste AECs recycling in an efficient and environmentally way.

Design and Analysis of In-Drum Outer Rotor BLDC Motor for Eddy Current Separator

Design and Analysis of In-Drum Outer Rotor BLDC Motor for Eddy Current Separator

Performance Determination of Novel Design Eddy Current Separator for Recycling of Non-Ferrous Metal Particles

Improvements were made in the study for the design of the conventional Eddy Current Separator (ECS) used for separating small sized non-ferrous particles in the waste. These improvements include decreasing the air gap between the material and magnetic drum, making the drum position adjustable and placing the splitter closer to the drum. Thus, small particles were separated with high efficiency. The magnetic drum was removed from inside the ECS conveyor belt system as design change and was placed as a separate unit. Hence, the force generated on the test material increased by about 5.5 times while the air gap between the non-ferrous materials and drum decreased from 3 mm to 1 mm. The non-metal material in the waste is separated before the drum in the novel design. Whereas non-ferrous metal particles are separated by falling into the splitter as a result of the force generated as soon as the particles fall on the drum. Every material that passes through the drum can be recycled as a result of moving the splitter closer to the contact point of the drum. In addition, the drum can also be used for the efficient separation of large particles since its position can be adjusted according to the size of the waste material. The performance of the novel design ECS was verified via analytical approaches, finite element analysis (FEA) and experimental studies.

Hollow Aluminum Particle in Eddy Current Separation of Recovering Waste Toner Cartridges

Abundant waste toner cartridges have been generated from the use of printers. They contain aluminum, plastic, steel, and toner. Waste toner cartridges will pollute the environment if they are not properly treated. An environment-friendly recovery line of waste toner cartridges had been constructed in our previous work. Eddy current separation was employed to separate aluminum particles from plastic particles of crushed waste toner cartridges. However, hollow aluminum particles existed in crushed waste toner cartridges, and they have a rather low separation rate from plastic particles. There was little information about hollow aluminum particles in eddy current separation. For improvement of the efficiency of eddy current separation, models of eddy current force and movement behaviors of hollow aluminum particles in eddy current separation were established. In a comparison of horizontal throws of hollow aluminum particles to solid aluminum particles, we found hollow characters greatly decreased the horizon...

Recycling of MSWI Bottom Ash: A Review of Chemical Barriers, Engineering Applications and Treatment Technologies

Bottom ash from municipal solid waste incineration is an underutilized secondary resource, which currently gains large attention due to increased landfill costs and the push towards a circular economy. Due to the high concentrations and mobility of pollutants, bottom ash cannot readily replace virgin construction materials. Over the last decade, many research efforts have addressed these issues in view of newly developed engineering applications. However, the required quality of bottom ash varies for each application. In this review we focus on the ternary relationship between engineering applications, chemical barriers/limitations and treatment technologies for municipal solid waste incinerator bottom ash. For each intended engineering application [loose (bulk) construction aggregates; sand, aggregate or cement replacement in concrete; raw material for cement or ceramics] the appropriate treatment technologies are selected to overcome identified chemical barriers. This allows future top-down design decisions, starting from the most promising engineering application of bottom ash. The main chemical barrier for bottom ash recycling as loose construction aggregates is the leaching of heavy metals and/or metalloids. This can be overcome by size separation, carbonation, mild heat treatment or by using mineral additives. In structured concrete, the presence of metallic aluminum or zinc causes early cracking and a high chloride concentration causes corrosion of reinforcement steel. Therefore, recent developments in wet/semi-dry separations facilitated enhanced eddy current separation to remove non-ferrous metals. The washing of bottom ash to remove chloride, is to date the sole technology to prepare bottom ash as raw material for cement kilns. Finally, when bottom ash is used as feedstock for ceramics production, recent knowledge was generated to allow for selecting thermal process parameters in such a way that leaching of both heavy metals and metalloids is minimized.

Eddy current separation technology for recycling printed circuit boards from crushed cell phones

Eddy Current Separation (ECS) is a classic method to separate light metal (aluminum) from plastic in the recycling industry. The aim of this paper is to present an innovative method that using the ECS to separate the printed circuit board (PCB) from the plastic generated from the crushed cell phone. A theoretical model of particle trajectory was established. On the basis of the computer simulation, it is found that ECS can be used to separate PCB from plastic with specific parameters. With the help of Design-Expert, the optimum separation conditions and selected operating parameters are analyzed with different velocities of feeding belt (v), rotating speeds of magnetic roller (ω), and radius of the particle (Rp). The separation gets its optimal condition (v = 1.18 m/s, ω = 3000 rpm, Rp = 8.44 mm) by model calculation. A practical experiment showed that the separation efficiency reached 95.54%.

Simulation of Eddy Current Separation of Gold Particles from Sands

The particles of gold can be reuse and recovered from electronics products and cards by sorting from many other metals or from sands. In mixtures of small gold spheres and sands have been sorted by an efficient method called eddy current separation able to separate the gold from a mixture of non ferrous particles. It’s a mining sort and recycling industry. This study is based on the ejected force created by the eddy currents induced and the rotation of drum. These eddy currents create a opposing magnetic field to create magnetodynamic repulsive force between permanent magnet of separator and gold particles, these last will be ejected in collector by gravity force.

Key factors of eddy current separation for recovering aluminum from crushed e-waste

Recovery of e-waste in China had caused serious pollutions. Eddy current separation is an environment-friendly technology of separating nonferrous metallic particles from crushed e-waste. However, due to complex particle characters, separation efficiency of traditional eddy current separator was low. In production, controllable operation factors of eddy current separation are feeding speed, (ωR−v), and Sp. There is little special information about influencing mechanism and critical parameters of these factors in eddy current separation. This paper provided the special information of these key factors in eddy current separation of recovering aluminum particles from crushed waste refrigerator cabinets. Detachment angles increased as the increase of (ωR−v). Separation efficiency increased with the growing of detachment angles. Aluminum particles were completely separated from plastic particles in critical parameters of feeding speed 0.5m/s and detachment angles greater than 6.61deg. Sp/Sm of aluminum particles in crushed waste refrigerators ranged from 0.08 to 0.51. Separation efficiency increased as the increase of Sp/Sm. This enlightened us to develop new separator to separate smaller nonferrous metallic particles in e-waste recovery. High feeding speed destroyed separation efficiency. However, greater Sp of aluminum particles brought positive impact on separation efficiency. Greater Sp could increase critical feeding speed to offer greater throughput of eddy current separation. This paper will guide eddy current separation in production of recovering nonferrous metals from crushed e-waste.

폐소형가전 선별·회수 공정의 전과정평가 연구

This study aims at evaluating the environmental impacts on recycling process for used small household appliances. The recycling process mainly consists of 1st-stage crushing, manual dismantling, magnetic separation, 2nd-stage crushing, eddy-current separation and near-infrared ray(NIR) separation. The overall capacity of the process is about 15 ton per day to treat used small household appliances. In this study, life-cycle assessment(LCA) methodology is applied to analyze major environmental parameters such as GWP, ADP, POCP, EP, etc. One of the major impact categories on the weight basis in the recycling process is global warming(GWP) 57.1 %, next to ADP 35.4 % and POCP 4.8 %, respectively. As a result of environmental impact on recovery of valuable resources/ton, the GWP of plastics for ABS is highest(51.41 %) compared to ferrous(8.61 %). The effects of environmental and economical benefit are also analyzed to compare with the amount of virgin materials to be recycled by recycled materials. In addition, recycled materials are also more economical in comparison to virgin materials due to the environmental avoiding effect by recycling. In conclusion, the key environmental issues related to the recycling of e-wastes are analyzed and therefore, the effective recycling process will contribute to mitigate global warming potential in the near future.

Design and development of a low cost technique for sorting household wastes using eddy current separation process

Recovery and recycling of metals from wastes have a major role in the global economy because of the scarcity of raw materials and the problem of environmental pollution. This paper reports a technical and economic study for the development of a low-cost eddy-current separator for household waste treatment. Waste treatment in African countries suffers a developmental delay owing to the cost of such equipment. On the basis of preliminary results obtained by numerical simulation of the physical phenomena, in order to test several possible configurations, a prototype device has been built and tested. The experimental results obtained have led to an optimal configuration in terms of separation efficiency. Thus, a second more efficient device has been successfully developed and tested. The economic analysis revealed the benefit of local manufacture for such a separator.

The Research of Simulation on Eddy Current Separation Process Based on MATLAB and COMSOL

The separation process of eddy current separator is effected by the structure parameters of magnetic roller, the working parameters of the separator and some parameters of the scrap metal, such as the material, the shape, the size and so on. This is a complex process of electric field and magnetic field coupling. During this process, the sorting function of separator is powered by the existence of the eddy current power in waste particles, and the separation effect is directly determined by the flying distance of the scrap metal in the separation process. This paper armed for studying the eddy current power and the flying distance of the waste particles in separation to realize the simulation of the separation process. The eddy current force was obtained by the finite element analysis of the magnetic roller based on COMSOL, and the flying distance was got by the joint simulation of COMSOL and MATLAB.

An Approach to Processing of Lithium-Ion Batteries for the Zero-Waste Recovery of Materials

A low-temperature, low-energy method for recovering all the valuable, economically viable, components from the spent lithium-ion batteries has been developed which has allowed the determination of pathways for complete recycling of the battery. Lithium present in the electrolyte has been selectively leached from lithium-ion batteries. Leaching conditions were optimized including time, temperature, solid/liquid ratio, and stirring velocity. All the samples were analyzed using ICP-MS for chemical composition. Leaching is conducted in a flotation machine that was able to separate plastics by flotation, creating bubbles without the use of any external chemical excess reagents. The pregnant solution was concentrated with lithium to a higher amount in order for it to be precipitated, and it was shown that the solution could be concentrated by recirculation of the leach solution. The next set of experiments were composed of battery shredding, steel separation by magnets, leaching with distilled water, and sizing using wet sieving to account for all the components of the battery. Every fraction is sent to rare-earth rolls separation and eddy current separation for full recovery.

Simulation research of eddy current separation technology in scrap copper based on ANSYS finite element method

Copper mineral resources are seriously insufficient in China. Scrap copper recycling is an inevitable choice to solve the shortage problem of the copper resources. To achieve rational utilization of the scrap copper in high quality, it's greatly significant to separate the scrap copper finely. In this paper, modeling and simulation analysis for the separation of the scrap copper with different materials by eddy current sensor based on ANSYS finite element method are made. The detection model for three situations such as the surface of the scrap copper is smooth and clean, coating and concavo-convex about four kinds of scrap copper materials (red copper, brass, manganin and bronze) are involved respectively in magnetic field lines, contour of magnetic flux intensity and equivalent impedance of sensor coil. Intercomparison and analysis of the simulation results testify that eddy current separation technology of the scrap copper is feasible. The simulation results are validated by the experiments.