Recycling technology is essential for managing waste and addressing environmental issues related to scrapping power lithium batteries. A closed -loop recycling technique was proposed in this work for maximizing usage of lithium (Li), manganese (Mn), cobalt (Co), and nickel (Ni) resources in spent ternary lithium battery (SNCMB) cathodes. A green and sustainable leaching process utilizes citric acid (CA) and hydrogen peroxide (HP) to efficiently extract Ni, Co, Mn, and Li from SNCMB cathodes. Maximizing leaching rates for Ni (96.69 %), Co (95.38 %), Mn (97.64 %), and Li (98.72 %) under optimal conditions (80 degrees C, 4 mol/L CA, 20 g/L solid to liquid (S/L) ratio, 2 vol% HP, 70 min). The Avrami equation models leaching kinetics, requiring a temperature of 80 degrees C to accelerate the process. Hydrogen -type strong acidic cation exchange resin (HR) effectively adsorbs Ni, Co, Mn, and Li ions from leachates through ion exchange under optimal conditions, reducing costs and eliminating the need for separating metals with similar chemical properties. This multi -stage adsorption recycling process renders leachates both economical and eco-friendly. The metal -enriched HR composite (HRC) from the ion -exchange process prepares ternary lithium battery (NCMB) cathodes to maximize metal usage. Microwave heating achieves excellent structure and electrochemical performance of regenerated ternary lithium battery (RNCM) cathodes, with 153.81 mAh/g discharge capacity at 0.1C rate and 90.92 % capacity retention after 50 cycles at 900 degrees C for 4 h. This innovative, efficient, and eco-friendly technique allows for closed -loop recycling of Ni, Co, Mn, and Li from SCNMB cathodes, providing new avenues for lithium battery recycling.

Based on the difficulty of extracting titanium from ilmenite, this study modified ilmenite by alkali roasting to improve the leaching rate of titanium. The leaching behaviour and kinetics of titanium in pretreated slag and the mechanism of limiting titanium leaching were studied. The results indicate that alkaline roasting pre-treatment of the ilmenite ore can transform acid-resistant FeTiO3 into more reactive Na2TiO3 and NaFeO2, which are more amenable to leaching. Simultaneously, under the following pre-treatment conditions—a sodium hydroxide to ilmenite ore mass ratio of 1.5:1, roasting temperature of 1123.15 K and roasting time of 1 h—the optimal leaching conditions are found to be a leaching temperature of 363.15 K, sulphuric acid mass fraction of 60

Plastic pyrolysis technology, as an efficient and stable path for chemical recycling of waste plastics, alleviates current energy pressures and solves the problem of continuous accumulation of waste plastics in the environment. At present, the vast majority of research on plastic pyrolysis is focused on how to improve the yield and quality of liquid fuels, while there is generally little research on the gases generated by plastic pyrolysis. However, gases such as H2, CH4, and light hydrocarbons generated during pyrolysis also have high utilization value, and have very considerable application prospects in chemical, aerospace, and metallurgical fields. In addition, compared with the separation difficulties of liquid products, the treatment of gas products is easier and more conducive to subsequent utilization. This article discusses and analyzes the yield and composition of gases generated by plastic in three different pyrolysis methods: direct pyrolysis, catalytic pyrolysis, and microwave pyrolysis. Compared to traditional direct pyrolysis, catalytic pyrolysis and microwave pyrolysis can treat plastic waste more efficiently and energy-efficient, and have higher gas yields. This article also discusses various factors such as temperature that influence the formation of gas products and their importance. Finally, the challenges faced are proposed, aiming to provide reference and direction for future research on improving the yield of gas generated by plastic pyrolysis.

During the exploitation of sphalerite resources, a considerable amount of low-grade oxysulfur Pb-Zn deposits is generated, which poses a significant threat to the environment and soil and water conservation in mining areas. Therefore, low-grade Pb-Zn resources urgently require source emission reduction and appropriate utilization. This study applied a mineral technology and conducted X-ray diffraction and scanning electron micro-scopy-energy dispersive X-ray spectroscopy to investigate the phase transformation and the mechanism un-derlying the volatilization of Pb and Zn at different times and temperatures. The Pb-Zn volatilization kinetics of a low-grade oxysulfur Pb-Zn ore by a one-step pyrometallurgical process in an argon atmosphere was studied, and the effects of different temperature conditions on the Zn volatilization process were investigated. The results showed that the Zn-containing phase in the raw material was decomposed to ZnO and ZnS upon heating. Moreover, ZnO was reduced via carbothermal reduction, whereas ZnS was reduced via a CaO-assisted carbo-thermal reaction and volatilized in the form of gaseous Zn. In the Pb-containing phase, PbSO4 generated PbO, Pb, and PbS in the presence of Fe, FeS, and CaO. PbO was volatilized in the form of gaseous Pb through carbothermal reduction and interactions between PbS and PbO. The Pb-Zn volatilization reaction conformed to the shrinking core model with a constant size, and the volatilization-based removal of Pb and Zn process was controlled by internal diffusion. A macroscopic kinetic model of the reaction was established on the basis of experimental data. The apparent activation energy of Pb and Zn volatilization was 163.90 and 328.19 kJ/mol, respectively. This study promotes the utilization of the low-grade oxysulfur Pb-Zn ore through a pyrometallurgical method to provide theoretical support for large-scale industrial treatments.

A substantial quantity of discarded tires has inflicted harm on the environment. Microwave pyrolysis of discarded tires emerges as an efficient and environmentally friendly method for their recycling. This research innovatively utilizes the characteristics of microwave rapid and selective heating to pyrolyze waste tires into porous graphene under the catalysis of KOH etching. Moreover, this study comprehensively investigates the dielectric characteristics and heating behavior of waste tires and different proportions of waste tire–KOH mixtures. It validates the preparation of graphene through KOH-catalyzed microwave pyrolysis of waste tires, tracking morphological and structural changes under varying temperature conditions. The results indicate that optimal dielectric performance of the material is achieved at an apparent density of 0.68 g/cm3 at room temperature. As the temperature increases, the dielectric constant gradually rises, particularly reaching a notable increase around 700 °C, and then stabilizes around 750 °C. Additionally, the study investigates the penetration depth and reflection loss of mixtures with different proportions, revealing the waste tire–KOH mass ratio of 1:2 demonstrates favorable dielectric properties. This research highlights the impressive microwave responsiveness of the waste tire–KOH mixture, Upon the addition of KOH, the mixed material exhibits an augmented dielectric constant and relative dielectric constant, supporting the viability of KOH-catalyzed microwave pyrolysis for producing porous graphene from waste tires. This method is expected to provide a new method for the valuable reuse of waste tires and a technology for large-scale, efficient and environmentally friendly production of graphene.

The quality of ruthenium (Ru) powders has a direct impact on the performance of sputtering Ru targets. This study employed spray granulation coupled with microwave calcination to prepare high-sphericity and uniform particle size Ru powders using ammonium hexachlororuthenate (IV) (AH). Spray granulation was applied to prepare AH powders with uniform particle size, high sphericity, and great dispersibility. AH@10, prepared by blending spherical AH powders and near-spherical Ru powders generated by microwave calcination at a mass ratio of 9:1, absorbs more microwaves than AH, which is promising for preparing Ru powders with faster and greater production than AH by microwave calcination. The response surface methodology (RSM) based on central composite design (CCD) was used to optimize the process of microwave calcination AH@10 in accordance with the thermal decomposition and self-reduction mechanism of AH. Three parallel verification experiments were performed under optimal microwave conditions (heating time 68.00 min, heating temperature 500 degrees C, and material mass 28 g), and the products were collected and characterized. The results show that the response surface model is accurate, and near-spherical Ru powder with high morphology was obtained after spray granulation and microwave calcination AH@10. This work is anticipated to produce Ru powders that could be used as a sputtering target in industry, as well as other high-performance metal powders.

Inexpensive iron-based catalysts are the most promising catalysts for microwave-assisted deconstruction of waste plastics. However, the microwave heating efficiency of most of the synthesized iron-based catalysts is very low, in particular, the FeAl catalyst was prepared by microwave combustion method, and its mixture with disposable medical masks (DMMs) was only heated to about 150 degrees C within 10 min. Here, we introduce the second-phase metals (Co or Ni) into the FeAl catalyst, resulting in the rearrangement of the catalyst structure and electrons to give the catalyst good microwave absorption ability. The mixture of the catalyst and DMMs can be quickly heated to above 900 degrees C in 10 min, especially after reaching the melting point of plastic, the instantaneous heating rate reaches 350 degrees C center dot min(-1). under the unique microwave hot-spot pyrolysis mechanism, DMMs can be rapidly pyrolyzed into carbon nanotubes (19.65 wt%) and gas (77.65 wt%) within 14 min due to the efficient dehydrogenation efficiency and activity of Co. The corresponding H-2 yield is up to 38.66 mmolH(2)center dot g(-1) DMMs, and the percentage of CO and H-2 in the gas is as high as 90 wt%. This work improves the microwave conversion efficiency of iron-based catalysts by introducing second phase metals, and waste DMMs were efficiently converted into CO, H-2 and CNTs, which can also be extended to other polymer or biomass chemical cycles.

The continuous exploitation of zinc blende resources leading to primary resources may not be sufficient for future requirements.

Inexpensive iron-based catalysts are the most promising catalysts for microwave pyrolysis of waste plastics, especially a large number of disposable medical masks (DMMs) with biological hazards produced by spread of COVID-19. However, most synthesized iron-based catalysts have very low microwave heating efficiency due to the enrichment state of iron. Here, we prepared FeAlOx catalysts using the microwave heating method and found that the microwave heating efficiency of amorphous iron and hematite is very low, indeed, these materials can hardly initiate pyrolysis at room temperature, which limits the application of iron-based catalysts in microwave pyrolysis. By contrast, a mixture of DMMs and low-valent iron oxides produced by hydrogen reduction at 500 degrees C can be heated by microwaves to temperatures above 900 degrees C under the same conditions. When the hydrogen reduction temperature was incerased to 800 degrees C, the content of metallic iron in the catalyst gradually increased from 0.34 to 21.43%, which enhanced the microwave response ability of the catalyst, and decreased the gas content in the pyrolysis product from 78.91 to 70.93 wt%; corresponding hydrogen yield also decreased from 29.03 to 25.02 mmolH(2)center dot g(DMMs)(-1). Moreover, the morphology of the deposited solid carbon gradually changed from multi-walled CNTs to bamboo-like CNTs. This study clarifies the pyrolysis mechanism of microwave-assisted iron catalysts and lays a theoretical foundation for their application in microwave pyrolysis.