Selective leaching of lithium from spent lithium-ion batteries using sulfuric acid and oxalic acid

Traditional hydrometallurgical methods for recovering spent lithium-ion batteries(LIBs)involve acid leaching to simultaneously extract all valuable metals into the leachate.These methods usually are followed by a series of separation steps such as precipitation,extraction,and stripping to separate the individual valuable metals.In this study,we present a process for selectively leaching lithium through the synergistic effect of sulfuric and oxalic acids.Under optimal leaching conditions(leaching time of 1.5 h,leaching temperature of 70°C,liquid-solid ratio of 4 mL/g,oxalic acid ratio of 1.3,and sulfuric acid ratio of 1.3),the lithium leaching efficiency reached89.6%,and the leaching efficiencies of Ni,Co,and Mn were 12.8%,6.5%,and 21.7%.X-ray diffraction(XRD)and inductively coupled plasma optical emission spectrometer(ICP-OES)analyses showed that most of the Ni,Co,and Mn in the raw material remained as solid residue oxides and oxalates.This study offers a new approach to enriching the relevant theory for selectively recovering lithium from spent LIBs.

Impact Analysis of the Electromagnetic Radiation from Substation

Damage and interference of the electromagnetic radiation on human body and electronic communication equipment generated by substa- tion were introduced firstly. By using scientific research method, strengths of the electromagnetic field in substations of 35, 110 and 220 kV was measured. According to detection result, distribution range and influence characteristics of the electromagnetic radiation generated by substation were analyzed. Finally, we put forward some countermeasures and suggestions for prevention and control of the electromagnetic radiation.

Impact Analysis of Electromagnetic Radiation from Communication Stations

[Objective] The study aims to analyze the effects of electromagnetic radiation from the communication stations on on surrounding environment. [ Method] The electromagnetic field intensity of the environment around communication stations was detected firstly, and then the impact of electromagnetic radiation from the communication stations on surrounding environment was analyzed, finally a series of countermeasures and suggestions were proposed to prevent electromagnetic radiation pollution. [ Result] The comprehensive electromagnetic field intensity of the environ- ment around mobile stations has positive correlation with the number of transmitting and receiving antennas. In addition, the comprehensive electro- magnetic field intensity is higher at high points compared with that at low points, showing that the comprehensive electromagnetic field intensity is positively correlated with point height. [ Conclusion] The research is of important significance to environmental protection and public health.

Development of Low-carbon and Sustainable Magnesium-bearing Cementitious Materials-based Solidification Approaches for Management of Problematic Soils

The production of traditional cementitious binders such as calcium-based Portland cement poses a serious challenge to the environment and society.Therefore,low-carbon,green and sustainable magnesium-based cementitious materials are developed to replace fully or partly Portland cement and reduce the consumption of natural resources and CO_(2)emissions.Three interesting techniques,including reactive MgO-activated industrial solid wastes,MgO-based cement and carbonation of magnesium-bearing materials,are elucidated to point to the necessity for developing novel magnesium-based cementitious materials.In the coming future,the carbonation of magnesium-rich industrial solid wastes or its combination with reactive MgO for application in various construction sectors such as soft ground improvement and concrete fabrication would be a promising approach to generate high-value products based on industrial solid wastes.

Privacy-Aware Examination Results Ranking for the Balance Between Teachers and Mothers

As the main parent and guardian, mothers are often concerned with the study performance of their children.More specifically, most mothers are eager to know the concrete examination scores of their children. However,with the continuous progress of modern education systems, most schools or teachers have now been forbidden to release sensitive student examination scores to the public due to privacy concerns, which has made it infeasible for mothers to know the real study level or examination performance of their children. Therefore, a conflict has come to exist between teachers and mothers, which harms the general growing up of students in their study. In view of this challenge, we propose a Privacy-aware Examination Results Ranking(PERR) method to attempt at balancing teachers’ privacy disclosure concerns and the mothers’ concerns over their children’s examination performance.By drawing on a relevant case study, we prove the effectiveness of the proposed PERR method in evaluating and ranking students according to their examination scores while at the same time securing sensitive student information.

Buildup of Sn@CNT nanorods by in-situ thermal plasma and the electronic transport behaviors

Monocrystal Sn nanorods encapsulated in the multi-walled carbon nanotubes(Sn@CNT NRs), were fabricated by a facile arc-discharge plasma process, using bulk Sn as the raw target and methane as the gaseous carbon source. The typical Sn@CNT NRs are 40–90 nm in diameter and400–500 nm in length. The CNTs protect the inner Sn nanorods from oxidation. Temperature dependent I–V curve and electronic resistance reveal that the dielectric behavior of Sn@CNT NRs is attributed to the multi-wall CNTs shell and follows Mott-David variable range hopping [ln R(T)∝T-1/4]model above the superconducting critical temperature of3.69 K, with semiconductor–superconductor transition(SST).Josephson junction of Sn/CNT/Sn layered structure is responsible for the superconducting behavior of Sn@CNT NRs.