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The improper disposal of retired lithium batteries will cause environmental pollution and a waste of resources. In this study, a waste lithium iron phosphate battery was used as a raw material, and cathode and metal materials in the battery were separated and recovered by mechanical crushing and electrostatic separation technology. The effects on material electrostatic separation of separation parameters such as the crushing particle size, the voltage of the static electrode, and the rotating speed of the grounding rotor were all studied combined with trajectory simulation and separation experiments. The results show that the crushing particle size of the material has the most significant impact on the separation effect, and the material separation effect primarily occurs in the range of 0.2–2.0 mm particle sizes. When the voltage of the static electrode is 30 kV, the rotating speed of the grounded rotor is 60 r/min, and the particle size is 0.4–0.8 mm, and the recovery rates for aluminum, copper, and lithium iron phosphate reach 93.2%, 91.1%, and 97.1%, respectively. In the recovery process for waste lithium batteries, using electrostatic separation technology instead of high-temperature roasting or chemical leaching can effectively improve the separation efficiency and reduce secondary pollution.

The problems of the uneven strip shape and low efficiency of tea de-enzyming and carding machines in the working process were addressed by analyzing the trajectory of tea particles and establishing a force model diagram of tea particles in the pot slot. The three-dimensional geometric model of the tea de-enzyming and carding machine was drawn using UG software, and the simulation model of tea particles was established using EDEM software. The work efficiency of the tea de-enzyming and carding machine was improved, and the rate of broken tea was reduced using the EDEM software to simulate the movement of tea particles in the pot slot under different heights of the convex bar, pot slot angle of inclination, and number of slots. The average velocity and interaction force curve of tea particles were obtained. The influence of the number of slots, the inclination angle of the slot, and the height of the convex bar on the effect of tea into strips were verified using a scheme design based on the quadratic regression orthogonal combination rotation test, and experimental research based on three factors and three levels was carried out. Design-Expert 11 software (Stat-Ease, Minneapolis, MN, USA) was used to optimize the response surface and analyze the regression model of the relevant test data. The 6CSL-800 tea de-enzyming (Anji Yuanfeng Tea Machinery Co., Ltd., Huzhou, China) and carding machine (Anji Yuanfeng Tea Machinery Co., Ltd., Huzhou, China) was used as the verification test prototype, six sets of verification tests were carried out, and the test results showed that the maximum value of the strip rate index and the minimum value of the broken tea rate index were obtained. The order of the indicators affecting the bar-type rate and broken tea rate of the de-enzyming and carding machine from high to low is as follows: the height of the convex bar, the inclination angle of the slot body, and the number of slots bodies. When the height of the convex bar was 10 mm, the inclination angle of the slot was 90°, the number of slots was 12, the bar-type rate was 89.45%, and the broken tea rate was 1.63%. The prediction results of the regression model of the bar-type rate and broken tea rate of the tea de-enzyming and carding machine were verified by employing six sets of control tests with the 6CSL-800 tea de-enzyming and carding machine as the validation test prototype. The actual values of the bar-type rate obtained from the six sets of control tests were 88.19%, 90.37%, and 87.33% (1,2,3 group), and the actual values of the broken tea rate were 1.66%, 1.69%, and 1.61% (4,5,6 group), with average values of 88.63% and 1.65%. The control test was basically consistent with the results of parameter optimization. The processed finished tea has good quality, which can provide theoretical reference for the optimization and design of tea de-enzyming and carding machines and similar tea machines in the future.

Sandy clay loam has the characteristics of both sand and clay. Because of these characteristics, both frictional resistance and adhesive resistance occur between the soil and tillage tool. The combined effect of the two frictional forces increases the external friction angle between the soil and tillage tool, thus increasing the working resistance. To address this issue, this study investigated the coupling effect of high pressure and hot air on the external friction angle by using a self-developed device to measure the external friction angle. Test results showed that high-pressure air between the soil and tillage tool formed a high-pressure air curtain layer which acted as a lubricant, thereby reducing the external friction angle. The external friction angle decreased as the airflow pressure increased. The reduction in the moisture content of the subsoil to less than 30% by the high-pressure hot air reduced the resistance between the soil and tillage tool. The approach with the high-pressure hot air curtain was verified in tests on a subsoiling shovel; the working resistance of the shovel under high-pressure hot air was reduced by 14.8%, demonstrating that this approach was effective in reducing the working resistance of the shovel.

Efficient separation of small-particle-size mixed electrode materials, which are crushed products obtained from the entire lithium iron phosphate battery, has always been challenging. Thus, a new method for recovering lithium iron phosphate battery electrode materials by heat treatment, ball milling, and foam flotation was proposed in this study. The difference in hydrophilicity of anode and cathode materials can be greatly improved by heat-treating and ball-milling pretreatment processes. The micro-mechanism of double enhancement of flotation effect by pretreatment process was revealed by means of micro-morphology characterization and thermogravimetric analysis. Finally, the effects of rotational speed and aeration on flotation effect were investigated through experiments. Results showed that after heat treatment at 480 ℃ for 20 min and ball milling for 3 min, the yield and grade of lithium iron phosphate reached 96.3% and 93.5%, respectively, at rotational speed of 2800 r/min and aeration rate of 180 L/h, and the loss of lithium ion was only 67.83 mg/L. This method offers a purified electrode material suitable for the subsequent hydrometallurgical recovery process, thereby presenting a novel approach to recovering waste lithium-ion batteries.

Among the common recycling methods for lithium battery materials, pyrometallurgy recycling leads to high energy consumption and carbon emission levels, and hydrometallurgy recycling generates many toxic byproducts. As a result, there are serious challenges to managing wastes in a harmless manner. In this study, a combination of ball milling pretreatment and eddy current separation is used to replace heat treatment in traditional lithium battery recovery methods to reduce the energy consumption and secondary pollution levels. A new eddy current separation motion model is established, and the effects of the shape coefficient and air resistance on the separation trajectory of battery materials are quantified. Theoretical and experimental results show that metal fragments suitable for carrying eddy currents are attainable by treating electrode plates with a 20 mm abrasive for 60 s. The recovery rates for copper, aluminum, and lithium iron phosphate reach 95.9%, 97.1%, and 93.4%, respectively, when the rotating speed of the magnetic rotor is 1000 rpm, and the shape coefficient of the material is 1.5. Therefore, eddy current separation is a promising method for separating metals and electrode materials from the electrode plates of lithium iron phosphate batteries.

Retired lithium nickel cobalt manganese oxide-type lithium-ion power batteries (NCMs) pose considerable challenges for recycling due to high contamination levels and low efficiency in the recovery process. Despite these complexities, NCMs contain significant amounts of precious metals, making them a substantial untapped resource with immense recycling potential. This study optimizes heat treatment conditions for NCMs focusing on cathode materials and the current collector. The optimal parameters of 280 °C, 2 h, and 60 s were identified through systematic discharge, disassembly, crushing, and sorting processes. Precious metal recovery rates exceeded 90%. Thermogravimetric-thermal differential analysis at 400 °C revealed the complete removal of bonding agents between the electrode materials. A comprehensive cost analysis was conducted using a mathematical model for retired power batteries revenue, scrutinizing the consumption costs and benefits of pyrometallurgical, hydrometallurgical, and physical recovery processes for NCMs. The input–output efficiencies were 6.56%, 28%, and 23%, respectively. This study supports the viability of physical recycling for a future mechanical–chemical combination approach to reduce production costs and environmental impacts. The proposed method holds economic, environmental, and industrial development value and provides a guide for sustainable recycling practices in the lithium-ion battery industry.

The culture of suspended kelp, such as Laminaria japonica Aresch, has arisen in nearshore areas for approximately 30 years since the 1980 s. This long-term activity has significant impact on the regional hydrodynamic and sedimentary environments. In this study the impact was investigated, based on synchronized multi-station data from continuous observations made within and around the culture area. In total, three current velocity profiles were identified inside and on the landward side of the culture area. Based on the current velocity profiles we calculated the boundary layer parameters, the fluxes of erosion/deposition, and the rate of sediment transport in different times at each observation site. Comparison between culture and non-culture periods showed that the presence of suspended kelp caused the reduction in the average flow velocity by approximately 49.5%, the bottom friction velocity by 24.8%, the seabed roughness length by 62.7%, and the shear stress and the flux of resuspended sediment by approximately 50%. From analyses in combination with the corresponding vertical variation of the suspended sediment distribution, it is revealed that the lifted sediments by resuspension is mixed with the upper suspended material, which will modify the regional distribution of suspended sediment. These changes in flow structure and sediment movement will accelerate seabed siltation, which corresponds to the changes in seabed erosion/deposition. However, under the influences of the seasonal changes in kelp growth the magnitude of change with the seabed siltation was not obvious inside the culture area, but a fundamental change was apparent around the culture area.

By combing satellite-derived ice motion and concentration with ice thickness fields from a popular model PIOMAS we obtain the estimates of ice volume flux passing the Fram Strait over the 1979–2012 period. Since current satellite and field observations for sea ice thickness are limited in time and space, the use of PIOMAS is expected to fill the gap by providing temporally continued ice thickness fields. Calculated monthly volume flux exhibits a prominent annual cycle with the peak record in March（roughly 145 km3/month） and the trough in August（10 km^3/month）. Annual ice volume flux（1 132 km^3） is primarily attributable to winter（October through May） outflow（approximately 92%）. Uncertainty in annual ice volume export is estimated to be 55 km^3（or 5.7%）. Our results also verified the extremely large volume flux appearing between late 1980 s and mid-1990 s. Nevertheless, no clear trend was found in our volume flux results. Ice motion is the primary factor in the determination of behavior of volume flux. Ice thickness presented a general decline trend may partly enhance or weaken the volume flux trend. Ice concentration exerted the least influences on modulating trends and variability in volume flux. Moreover, the linkage between winter ice volume flux and three established Arctic atmospheric schemes were examined. Compared to NAO, the DA and EOF3 mechanism explains a larger part of variations of ice volume flux across the strait.

In this study, changes in Arctic sea ice thickness for each ice age category were examined based on satellite observations and modelled results. Interannual changes obtained from Ice, Cloud, and Land Elevation Satellite（ICESat）-based results show a thickness reduction over perennial sea ice（ice that survives at least one melt season with an age of no less than 2 year） up to approximately 0.5–1.0 m and 0.6–0.8 m（depending on ice age） during the investigated winter and autumn ICESat periods, respectively. Pan-Arctic Ice Ocean Modeling and Assimilation System（PIOMAS）-based results provide a view of a continued thickness reduction over the past four decades. Compared to 1980 s, there is a clear thickness drop of roughly 0.50 m in 2010 s for perennial ice. This overall decrease in sea ice thickness can be in part attributed to the amplified warming climate in north latitudes. Besides, we figure out that strongly anomalous southerly summer surface winds may play an important role in prompting the thickness decline in perennial ice zone through transporting heat deposited in open water（primarily via albedo feedback） in Eurasian sector deep into a broader sea ice regime in central Arctic Ocean. This heat source is responsible for enhanced ice bottom melting, leading to further reduction in ice thickness.

Sea ice is a quite sensitive indicator in response to regional and global climate changes. Based on monthly mean Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) sea ice thickness fields, we computed the conductive heat flux (CHF) in the Arctic Ocean in the four winter months (November-February) for a long period of 36 years (1979-2014). The calculated results for each month manifest the increasing extension of the domain with high CHF values since 1979 till 2014. In 2014, regions of roughly 90% of the central Arctic Ocean have been dominated by the CHF values larger than 18Wm?2 (November-December) and 12Wm?2 (January-February), especially significant in the shelf seas around the Arctic Ocean. Moreover, the population distribution frequency (PDF) patterns of the CHF with time show gradually peak shifting toward increased CHF values. The spatiotemporal patterns in terms of the trends in sea ice thickness and other three geophysical parameters, surface air temperature (SAT), sea ice thickness (SIT), and CHF, are well coupled. This suggests that the thinner sea ice cover preconditions for the more oceanic heat loss into atmosphere (as suggested by increased CHF values), which probably contributes to warmer atmosphere which in turn in the long run will cause thinner ice cover. This represents a positive feedback mechanism of which the overall effects would amplify the Arctic climate changes.