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In this work, the alkaline refining of arsenic in crude lead was studied with a mixture of sodium hydroxide and sodium carbonate as alkaline refining agents. Taking the arsenic removal rate as the research object, the effects of reaction temperature, holding time, Na2CO3:NaOH, the dosage of refining agent were investigated. The arsenic removal rate is 79.09% under the optimum experimental conditions as follows: reaction temperature 823 K, holding time 60 min, Na2CO3:NaOH 1:4, refining agent dosage 10%. The oxidation purification mechanism of arsenic was studied by XPS, SEM-EDS, XRD and FT-IR. The results show that arsenic in the crude lead is gradually oxidized by oxygen and lead oxide during arsenic removal process, and the arsenic trioxide is eventually converted into sodium arsenate (Na3AsO4) and lead arsenate (Pb2As2O7) in the slag.

A method of conventional roasting pretreatment combined with ultrasonic enhanced leaching with ammonium acetate was proposed to solve the difficult problem of lead in electrolytic manganese anode mud. The effects of concentration, liquid&ndash, solid ratio, temperature, leaching time and rotating speed on the leaching process under conventional and ultrasonic conditions were studied, and the lead leaching rate can be as high as 93.09% under optimized process parameters. A leaching kinetic model under conventional and ultrasonic conditions was established to explore the restrictive links of the leaching process. The results show that the leaching process under both conventional and ultrasonic conditions is controlled by diffusion, and the activation energies are 29.40 kJ/mol and 26.95 kJ/mol for the conventional and ultrasound enhance leaching processes, respectively.

Zinc and iron were separated from the spent pickling solution by extraction with methyl trioctyl ammonium chloride (Aliquat 336). The purpose of the extraction experiment is to determine a variety of parameters (e.g. addition of octanol, contact time, phase ratio, [H+] concentration and Aliquat 336 concentration). Under optimal extraction conditions, the zinc extraction in one stage was above 92.4% and the separation coefficient βZn/Fe could reach 273 with initial zinc concentration 17.6 g/L, iron concentration 141.1 g/L and [H+] = 1.4 M. The zinc extraction mechanism was analyzed FT-IR spectroscopy and slope method. Zn(II) after extracting was comparative studied using different stripping agents. Recycling tests were also carried out, indicating that the extractant had a stable extraction performance, retaining 91.2% extraction efficiency of fresh extractant after 5 cycles.

The effect of a new ionic liquid additive 1-butyl-3-methylimidazolium hydrogen sulfate-[BMIM]HSO 4 on the kinetics of copper electro-deposition from acidic sulfate solution was investigated by cyclic voltammetry, polarization and electrochemical impedance measurements and compared with those exerted by the conventional additive, thiourea. Results from cyclic voltammetry and kinetic parameters such as Tafel slope, transfer coefficient and exchange current density obtained from Tafel plots, indicated that [BMIM]HSO 4 had a pronounced inhibiting effect on Cu 2+ electro-reduction and led to more leveled and fine-grained cathodic deposits. In addition, [BMIM]HSO 4 was found to inhibit the charge transfer and slightly change the copper electro-deposition mechanism compared to the absence of additives. Data obtained from X-ray diffraction spectra revealed that the presence of these additives did not change the crystal structure of the electro-deposited copper but strongly affected the crystallographic orientation of the crystal planes.