Distribution of the complex sulfide raw stuff components on roasting with soda, aqueous and acid leaching of calcine

In this paper, nickel-containing residue, a typical solid waste produced in the battery production process, was used to study the cavitation characteristics of ultrasonic waves in a liquid–solid reaction. The ultrasonically-enhanced leaching technology for multicomponent and complex nickel-containing residue was studied through systematic ultrasonic-conventional comparative experiments. An ultrasonic leaching kinetics model was established which provided reliable technological guidance and basic theory for the comprehensive utilization of nickel-containing residue. In the study, it was found that ultrasonically-enhanced leaching for 40 min obtained the same result as conventional leaching for 80 min, and the Ni extraction degree reached more than 95%. According to the kinetic fitting of the leaching process, it was found that the sulfuric acid leaching process belonged to the diffusion-controlled model of solid product layers under conventional and ultrasonic conditions, and the activation energy of the reaction was Ea1 = 17.74 kJ/mol and Ea2 = 5.04 kJ/mol, respectively.

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Electrocatalysis for Oxygen Reduction Reaction on EDTAFeNa and Melamine co-Derived Self-Supported Fe-N-C Materials

Catalysts ◽

10.3390/catal11050623 ◽

2021 ◽

Vol 11 (5) ◽

pp. 623

Author(s):

Mengfan Shen ◽

Ziwei Meng ◽

Tong Xue ◽

Hongfang Shen ◽

Xiang-Hui Yan

Keyword(s):

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Large Scale ◽

Acid Leaching ◽

Reduction Reaction ◽

Scale Production ◽

Final Annealing ◽

High Performing ◽

Half Wave ◽

Mesoscopic Structure

To explore high-performing alternatives to platinum-based catalysts is highly desirable for lowering costs and thus promoting fuel cell commercialization. Herein, self-supported Fe-N-C materials were prepared by the pyrolysis of dual precursors including EDTA ferric sodium (EDTAFeNa) and melamine (MA), followed by acid-leaching and final annealing. Towards an oxygen reduction reaction (ORR) in 0.1 M KOH, the as-prepared MA/EDTAFeNa-HT2 delivered onset (Eonset) and half-wave (E1/2) potentials of 0.97 and 0.84 V vs. RHE, respectively, identical with that of a state-of-the-art Pt/C catalyst, accompanied with predominantly a four-electron pathway. The introduction of MA and extension of acid-leaching promoted a positive shift of 50 mV for E1/2 relative to that of only the EDTAFeNa-derived counterpart. It was revealed that the enhancement of ORR activity is attributed to a decrease in magnetic Fe species and increase in pyridinic/quanternary nitrogen content whilst nearly excluding effects of the graphitization degree, variety of crystalline iron species, and mesoscopic structure. The usage of dual precursors exhibited great potential for the large-scale production of inexpensive and efficient Fe-N-C materials.

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Recovery of Zinc and Silver from Zinc Acid-Leaching Residues with Reduction of Their Environmental Impact Using a Novel Water Leaching-Flotation Process

Minerals ◽

10.3390/min11060586 ◽

2021 ◽

Vol 11 (6) ◽

pp. 586

Author(s):

Yunpeng Du ◽

Xiong Tong ◽

Xian Xie ◽

Wenjie Zhang ◽

Hanxu Yang ◽

...

Keyword(s):

Hazardous Waste ◽

Acid Leaching ◽

Copper Recovery ◽

Water Leaching ◽

Flotation Process ◽

Metal Levels ◽

Valuable Metals ◽

Leaching Experiments ◽

Zinc Hydrometallurgy ◽

Poor Stability

Zinc-leaching residue (ZLR) is a strongly acidic hazardous waste; it has poor stability, high heavy metal levels, and releases toxic elements into the environment. ZLR has potential as a valuable resource, because it contains elevated levels of zinc and silver. In this paper, the recovery of zinc (Zn) and silver (Ag) from ZLR wastes from zinc hydrometallurgy workshops using water leaching followed by flotation was studied. During water leaching experiments, the zinc and copper recovery rates were 38% and 61%, respectively. Thereafter, various flotation testing parameters were optimized and included grinding time, reagent dosages, pulp density, flotation time, and type of adjuster. Experimental results demonstrated this flotation method successfully recycled Ag and Zn. A froth product containing more than 9256.41 g/t Ag and 12.26% Zn was produced from the ZLR with approximately 80.32% Ag and 42.88% Zn recoveries. The toxicity characteristic leaching procedure (TCLP) results indicated the water-leaching flotation process not only recycled valuable metals such as zinc and silver in zinc-containing hazardous wastes but lowered the hazardous waste levels to those of general wastes and recycled wastes in an efficient, economical, and environmentally friendly way.

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Regeneration of LiFePO4 from spent lithium-ion battery by a facile closed-loop process featuring acid leaching and hydrothermal synthesis

Green Chemistry ◽

10.1039/d1gc00483b ◽

2021 ◽

Author(s):

Yifan Song ◽

Boyi Xie ◽

Shuya Lei ◽

Shaole Song ◽

Wei Sun ◽

...

Keyword(s):

Hydrothermal Synthesis ◽

Lithium Ion Battery ◽

Closed Loop ◽

Acid Leaching ◽

Lithium Ion ◽

Power Battery

As a widely used power battery, the scrapping boom of LiFePO4 (LFP) battery is coming. Both pyrometallurgical repair and hydrometallurgical processes have been applied in the recycling of spent LFP...

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