从废旧锂离子电池氨浸液中回收钴并制备微球状四氧化三钴

提出一种通过蒸氨和相变从氨性溶液中回收钴并制备微球状Co_(3)O_(4)的工艺。作为热力学基础,首先分析钴在不同NH_(3)和CO_(3)^(2-)浓度中的溶解度;然后讨论不同的蒸氨条件对钴回收率的影响。通过蒸氨,可以回收超过94%的钴和96%的氨,钴以碳酸钴铵复盐形式沉淀。前驱体沉淀机理的分析结果表明,钴的析出过程有两个阶段,并且在第二阶段的沉淀速度明显加快。在相变过程中,研究温度对焙烧产物的影响,在300℃时可获得具有微孔结构的微球状Co_(3)O_(4);而在750℃时可获得具有介孔结构和高自旋状态的Co_(3)O_(4)。

Deep cleaning of a metallurgical zinc leaching residue and recovery of valuable metals

Huge quantities of zinc leaching residues(ZLRs) generated from zinc production are dumped continuously around the world and pose a potential environmental threat because of their considerable amounts of entrained heavy metals(mainly lead). Most ZLRs have not been properly treated and the valuable metals in them have not yet been effectively recovered. Herein, the deep cleaning of a ZLR and recovery of valuable metals via a hydrometallurgical route were investigated. The cleaning process consists of two essential stages: acid leaching followed by calcium chloride leaching. The optimum conditions for extracting zinc, copper, and indium by acid leaching were a sulfuric acid concentration of 200 g·L^(-1), a liquid/solid ratio of 4:1(m L/g), a leaching time of 2 h, and a temperature of 90°C. For lead and silver extractions, the optimum conditions were a calcium chloride concentration of 400 g·L^(-1), a pH value of 1.0, a leaching time of 1 h, and a temperature of 30°C. After calcium chloride leaching, silver and lead were extracted out and the lead was finally recovered as electrolytic lead by electrowinning. The anglesite phase, which poses the greatest potential environmental hazard, was removed from the ZLR after deep cleaning, thus reducing the cost of environmental management of ZLRs. The treatment of chlorine and spent electrolyte generated in the process was discussed.

Electrochemical behavior and corrosion resistance of IrO2–ZrO2 binary oxide coatings for promoting oxygen evolution in sulfuric acid solution

In this study,we prepared Ti/IrO2–ZrO2 electrodes with different ZrO2 contents using zirconium-n-butoxide(C16H36O4Zr)and chloroiridic acid(H2IrCl6)via a sol–gel route.To explore the effect of ZrO2 content on the surface properties and electrochemical behavior of electrodes,we performed physical characterizations and electrochemical measurements.The obtained results revealed that the binary oxide coating was composed of rutile IrO2,amorphous ZrO2,and an IrO2–ZrO2 solid solution.The IrO2–ZrO2 binary oxide coatings exhibited cracked structures with flat regions.A slight incorporation of ZrO2 promoted the crystallization of the active component IrO2.However,the crystallization of IrO2 was hindered when the added ZrO2 content was greater than 30at%.The appropriate incorporation of ZrO2 enhanced the electrocatalytic performance of the pure IrO2 coating.The Ti/70at%IrO2–30at%ZrO2 electrode,with its large active surface area,improved electrocatalytic activity,long service lifetime,and especially,lower cost,is the most effective for promoting oxygen evolution in sulfuric acid solution.

Recovery and regeneration of LiFePO_(4)from spent lithium-ion batteries via a novel pretreatment process

The recycling of spent LiFePO_(4)batteries has received extensive attention due to its environmental impact and economic benefit.In the pretreatment process of spent LiFePO_(4)batteries,the separation of active materials and current collectors determines the difficulty of the re-covery process and product quality.In this work,a facile and efficient pretreatment process is first proposed.After only freezing the electrode pieces and immersing them in boiling water,LiFePO_(4)materials were peeled from the Al foil.Then,after roasting under an inert atmosphere and sieving,all the cathode and anode active materials were easily and efficiently separated from the Al and Cu foils.The active materials were subjected to acid leaching,and the leaching solution was further used to prepare FePO_(4)and Li_(2)CO_(3).Finally,the battery-grade FePO_(4)and Li_(2)CO_(3)were used to re-synthesize LiFePO_(4)/C via the carbon thermal reduction method.The discharge capacities of re-synthesized LiFePO_(4)/C cathode were 144.2,139.0,133.2,125.5,and 110.5 mA·h·g−1 at rates of 0.1,0.5,1,2,and 5 C,which satisfies the requirement for middle-end LiFePO_(4)batteries.The whole process is environmental and has great potential for industrial-scale recycling of spent lithium-ion batteries.

Recovery of iron from copper tailings via low-temperature direct reduction and magnetic separation: process optimization and mineralogical study

Currently, the majority of copper tailings are not effectively developed. Worldwide, large amounts of copper tailings generated from copper production are continuously dumped, posing a potential environmental threat. Herein, the recovery of iron from copper tailings via low-temperature direct reduction and magnetic separation was conducted; process optimization was carried out, and the corresponding mineralogy was investigated. The reduction time, reduction temperature, reducing agent (coal), calcium chloride additive, grinding time, and magnetic field intensity were examined for process optimization. Mineralogical analyses of the sample, reduced pellets, and magnetic concentrate under various conditions were performed by X-ray diffraction, optical microscopy, and scanning electron microscopy-energy-dispersive X-ray spectrometry to elucidate the iron reduction and growth mechanisms. The results indicated that the optimum parameters of iron recovery include a reduction temperature of 1150A degrees C, a reduction time of 120 min, a coal dosage of 25%, a calcium chloride dosage of 2.5%, a magnetic field intensity of 100 mT, and a grinding time of 1 min. Under these conditions, the iron grade in the magnetic concentrate was greater than 90%, with an iron recovery ratio greater than 95%.

直线切割吻合器在腹腔镜辅助远端胃癌根治术Roux-en-Y式吻合术中的应用

目的探讨直线切割吻合器在腹腔镜辅助远端胃癌根治术(LDG)Roux-en-Y式吻合术中的应用效果。方法选取2019年3月-2021年3月该院行LDG Roux-en-Y式吻合术的患者126例,按照随机数表法分为观察组(n=63)和对照组(n=63),观察组采用直线切割吻合器实施Roux-en-Y式吻合术,对照组采用圆形吻合器实施Roux-en-Y式吻合术。统计并分析两组患者手术时间、术中出血量、清扫淋巴结数量、阳性淋巴结数量、术后恢复排气时间、首次进流食时间、拔除引流管时间和术后并发症发生率,术后3个月采用健康调查量表36(SF-36)比较两组患者的生活质量。结果两组患者手术时间、术中出血量、清扫淋巴结数量和阳性淋巴结数量比较,差异均无统计学意义(P>0.05);与对照组比较,观察组术后恢复排气时间、首次进流食时间和拔除引流管时间均较短(P<0.05);两组患者住院总费用比较,差异无统计学意义(P>0.05),观察组术后住院时间明显短于对照组(P<0.05);与对照组比较,观察组并发症发生率更低(P<0.05);术后3个月随访,观察组SF-36评分明显高于对照组(P<0.05)。结论与圆形吻合器相比,直线切割吻合器应用于LDG Roux-en-Y式吻合术中,能够有效提高术中和术后安全性,促进患者术后恢复,改善患者术后生活质量。

Two-stage reduction for the preparation of ferronickel alloy from nickel laterite ore with low Co and high MgO contents

The preparation of ferronickel alloy from the nickel laterite ore with low Co and high MgO contents was studied by using a pre-reduction-smelting method. The effects of reduction time, calcination temperature, quantity of reductant and calcium oxide (CaO), and pellet diameter on the reduction ratio of Fe and on the pellet strength were investigated. The results show that, for a roasting temperature > 800 A degrees C, a roasting time > 30 min, 1.5wt% added anthracite coal, 5wt% added CaO, and a pellet size of similar to 10 mm, the reduction ratio of Fe exceeds 70% and the compressive strength of the pellets exceeds 10 kg per pellet. Reduction smelting experiments were performed by varying the smelting time, temperature, quantity of reductant and CaO, and reduction ratio of Fe in the pellets. Optimal conditions for the reduction smelting process are as follows: smelting time, 30-45 min; smelting temperature, 1550A degrees C; quantity of reductant, 4wt%-5wt%; and quantity of CaO, 5wt%; leading to an Fe reduction ratio of 75% in the pellets. In addition, the mineral composition of the raw ore and that during the reduction process were investigated by process mineralogy.

Preliminarily study of Saturn’s upper atmosphere density by observing Cassini plunging via China’s deep space station

When the Cassini spacecraft finally plunged into the Saturnian atmosphere on 2017 September15,China’s deep space telescope pointed to Saturn to observe Cassini and study the Saturnian upper neutral atmosphere.In this first Chinese Saturnian radio science experiment,X band Doppler velocity radio science data between the deep space telescope and the Cassini spacecraft were obtained.After removing Saturnian and solar gravity effects,Earth rotation effect,the remaining Saturnian atmosphere drag information was retrieved in the Cassini final plunge progress.Saturn’s upper neutral atmosphere mass density profile is approximately estimated based on atmosphere mass density derived principally by real orbit measurement data.Saturn’s upper neutral atmosphere mass density from 76000 km to 1400 km is estimated from the orbit measurement data,the mass density results are about from 1.4×10^-15 kg cm^-3 to 2.5×10^-14 kg cm^-3.

A new method of quality improvement for quadrilateral mesh based on small polygon reconnection

In this paper, a new method of topological cleanup for quadrilateral mesh is presented. The method first selects a patch of mesh around an irregular node. It then seeks the best connection of the selected patch according to its irregular valence using a new topological operation： small polygon reconnection （SPR）. By replacing the original patch with an optimal one that has less irregular valence, mesh quality can be improved. Three applications based on the proposed approach are enumerated： （1） improving the quality of a quadrilateral mesh, （2） converting a triangular mesh to a quadrilateral one, and （3） adapting a triangle generator to a quadrilateral one. The presented method is highly effective in all three applications.

Selective lithium recovery from black powder of spent lithiumion batteries via sulfation reaction:phase conversion and impurities influence

The aim of this study is to present a new understanding for the selective lithium recovery from spent lithium-ion batteries(LIBs)via sulfation roasting.The composition of roasting products and reaction behavior of impurity elements were analyzed through thermodynamic calculations.Then,the effects of sulfuric acid dosage,roasting temperature,roasting time,and impurity elements were assessed on the leaching efficiency of valuable metals.Characterization methods such as X-ray diffraction(XRD),scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS),and X-ray photoelectron spectroscopy(XPS)were employed to analyze the phase transformation mechanism during roasting process.The results indicate that after sulfation roasting(n(H_(2)SO_(4)):n(Li)=0.5,550℃,2 h),94%lithium can be selectively recovered by water leaching and more than 95%Ni,Co,and Mn can be leached through acid leaching without the addition of reduction agent.During the sulfation roasting process,the lithium in LiNi_(x)Mn_(y)Co_zO_(2)is mainly converted to Li_(2)SO_(4),while the Ni,Co and Mn are first transformed to sulfate and then converted into oxide form.In addition,impurity elements such as Al and F will combine with lithium to form LiF and LiAlO_(2),which will reduce the leaching rate of lithium.These results provide a new understanding on the mechanisms of phase conversion during sulfation roasting and reveal the influence of impurity elements for the lithium recovery from spent LIBs.

A new 8-connected self-penetrating metal-organic framework based on dinuclear cadmium clusters as secondary building units

A new metal-organic framework（MOF） based on metal clusters as secondary building units（SBU）,has been synthesized and structurally characterized.The reported MOF presents an interesting 8-connected self-penetrating coordination network based on dinuclear cadmium cluster with a 4^（24）·5·6~3 topology. Moreover,the thermal stability and luminescence property of this compound have been investigated.