| E-waste has been considered as"city-mine"due to containing aboundant metals. However, there was a lack in recovery technology and heavy secondary pollution had been produced. Developing new technologies and equipments have been the pressing demand for recovering e-waste. In this study, recovery technologies of waste toner cartridges (TCs) and refrigerator cabinets (RCs) were proposed based on the analysis of their components. Eddy current separation was employed as a key technology in the recovery technologies. Then, for improving the separation rate of eddy current separation (ECS), model of eddy current force and models for calculating the separation distance between different kinds of particles were constructed. Based on the proposed recovery technologies, production lines for recovering waste TCs and RCs were constructed and the operation paramenters of every process were studied. In finals, risk assessments of the recovery lines were made on their environment-friendly performance.Based on the analysis of comprised materials and pollution factors, a recovery technology of waste TCs was proposed including closed shearing, cyclone separation, bag-type dust collection, magnetic separation, and ECS. For preventing the leakage of CFC-11 gas, recovering technology of waste RCs was proposed after analysing the comprised materials. It included closed shearing, activated carbon adsorption, air current separation, magnetic separation, and ECS.In the recovery technologies of waste TCs and waste RCs, separation rate of ECS was low because of its abundant influenced factors. According to orthogonal experimental design, operation parameters of ECS were investigated. The experimental results indicated that speed difference between feeding speed and rotation speed of magnetic field (ωR-v) was the key influencing factor. Feeding speed was general influencing factor. Collection position of particles was subordination influencing factor. Separation rate was improved as the increasing of (ωR-v) and the decreasing of feeding speed. Collection position 0.9 m was the optimizing parameters of the eddy current separator in lab.New models for computing the acting force between particle and eddy current separator were established for guiding operation of ECS, configuration design of separator, and shearing mode of materials. The models were tested by the calculation and investigation of detachment angle (α0) of particle in ECS. Compared to former models, new models had the advantage on providing more detailed shape parameters of particle such as radius, length, width, thickness, and circumference. Furthermore, influencing factors of magnetic drum radius and magnetic field intensity of separator surface were added in the new models.Models for calculating separation distance between different particles in ECS were established for investigating the influencing factors. The models can be used to forecast separation quality of ECS by calculating the separating distances. Based on the analysis of the calculated separation distances, sequence of the influencing factors was derived as: particle size>rotation speed of magnetic field>shape of particle. Then, the approaches for improving the separation quality of eddy current separation were discussed. A new eddy current separator was designed for obtaining better separation quality according to the suggestion of the approaches. Additionally, the investigation of the exiting point of particle from magnetic field boundary extended the scope of theoretical investigation of ECS.Production lines of recovering waste TCs and waste RCs were constructed in enterprise based on the proposed recovery technologies. The operation parameters of every process were researched.(i) Optimized operation parameters of the recovering line of waste TCs were given in follows. Rotation speed of shearing machine was 1200 rpm, size of screen hole of shearing machine was 15mm, and circulating water should be fixed on shearing machine. Wind speed of the fans of cyclone separation and bag-type dust collector were 1.4 m/s and 0.3 m/s respectively. Rotation speed of magnetic separator was 350 rpm (3.3 m/s). Feeding speed of eddy current separator was 40 rpm (0.4 m/s), rotation speed of magnetic drum was 800 rpm (7.5 m/s).The recovery capability of waste TCs recovery line was 500 kg/h and recovery rate was 98.2% with the power demand 190 kW.(ii) Optimized operation parameters of the recovering line of waste RCs were given in follows. Rotation speed of shearing machine was 1800 rpm, size of the screen hole of shearing machine was 10mm, and circulating water should be fixed on shearing machine. Rotation speed of the fan of activated carbon adsorption tower was 1200 rpm. Wind speed of the fan of air current separator was 0.95 m/s. Rotation speed of magnetic separator was 350 rpm (3.3 m/s). Feeding speed of eddy current separator was 40 rpm (0.4 m/s), rotation speed of magnetic drum was 1000 rpm (7.5 m/s). The recovery capability of waste RCs recovery line was 773.8 kg/h and recovery rate was 97.6% with the power demand 240 kW.Risk assessment of the recovering line of waste TCs were made on noise level, density of airborne particles, and leakage of toner in recovering process. Risk assessments of the recovering line of waste RCs were made on noise levels, leakage of CFC-11, density of airborne particles, and the exposure of heavy metals in the recovering process.(i) Results of risk assessment of the recovering line of waste TCs were given in follows. Noise levels of shearing and agitating-magnetic separation exceeded 90 dB(A) (Occupational Safety and Health Standards). After employing acoustic hood, the noise level was controlled to 67.6 dB(A). Concentrations of airborne particles (TSP,PM10) met the the Indoor Air Quality Standard of Chinese. The highest density of organic particles from toner in TSP samples was 0.026 mg/m3, and little organic particle was found in PM10 samples. It meant that little risk was brought to human healthy by organic particle of toner in recovering process.(ii) Results of risk assessment of the recovering line of waste RCs were given in follows.Noise levels of shearing process exceeded 90 dB(A) (the Occupational Safety and Health Standards). After employing acoustic hood, the noise level was controlled to 69.7 dB(A). Concentrations of CFC-11 around shearing machine and air current separation were 6-9 mg/m3 and 5-7 mg/m3, lower than the concentration of fluoride in Ambient Air Quality Standard of Chinese. Although high concentration (216-739 mg/m3) of CFC-11 was detected in the inner of shearing machine, little CFC-11 was detected in workshop and the gas outlet of actived carbon adsorption tower due to its running. the concentrations of airborne particles (TSP,PM10) met the Indoor Air Quality Standard of Chinese and the concentration of heavy metals in TSP and PM10 were safe for workers. High concentrations of copper (1672-11925 mg/kg), lead (356.1-11490 mg/kg), and tin (211.9-686.5 mg/kg) were detected in the residual ashes of the recovering line, and concentrations of copper and lead exceeded the heavy metal concentrations in Environment Quality Standard for Soils thirtyfold and twentyfold respectively.This study offered the theoretical basis of eddy current separation for recovering waste toner cartridges and refrigerator cabinets. Meanwhile, high-efficiency, environment-friendly, and cost saving production lines for recovering waste toner cartridges and refrigerator cabinets were developed. The works of this study may contribute little to the technology informations for e-waste recovering.
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