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In this study, a new metallurgical system for treating electrolytic manganese anode sludge by microwave roasting and alkaline leaching system was developed, and the lead leaching behaviour was studied. The XRD results show that Pb in anode sludge is mainly in the form of PbSO4 after microwave roasting at 850°C, as a result, the leaching rate of Pb is improved. The results show that the leaching rate of lead can reach 93.89% under the conditions of liquid-solid ratio of 7:1, leaching time of 30 min, leaching temperature of 40°C, and the concentration of sodium hydroxide of 8%. The addition of tartaric acid can further improve the lead leaching rate, FT-IR analysis showed that the coordination form of lead and tartaric acid. Lead and tartaric acid ions (L) form three coordination compounds, PbL, Pb2L2 and Pb2L3, which can only exist in alkaline solution.

In this study, the Ag and Cu evolution in the sintering dust was extracted by chlorination roasting process, and the mechanism of the process was analyzed by atomic absorption spectroscopy, X-ray fluorescence, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectrometry. In addition, in order to better understand the chlorination roasting process, the mechanism and thermodynamics of roasting reaction were analyzed. The recovery of Ag and Cu reached 99.05% and 59.32%, respectively, under the conditions of roasting temperature of 1423 K, holding time of 60 min, and the air flow rate of 400 L/h. Thermodynamic analysis showed that MgO and SiO2 could promote the production of Cl2 and HCl and that CuO could be chlorinated by Cl2 at 1421 K, but it was not amenable for HCl. Compared with CuO, Ag was more easily chlorinated at high temperatures. Experimental results indicate that silver and copper can be efficiently extracted, indicating that the chlorination roasting is a promising pyrometallurgical treatment for the recycling of sintering dust.

Sintering dust is considered as a hazardous waste material owing to its high heavy metal content. In this study, a new technology for the treatment of sintering dust via chlorination roasting was developed. The chlorination behavior of Pb at high temperatures was studied. The volatilization behavior of Pb and Cl was found using different analytical techniques, such as scanning electron microscopy and energy dispersive X-ray spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy, X-ray fluorescence, and atomic absorption spectroscopy. In addition, the thermodynamics and kinetics of the chlorination mechanism of Pb at high temperatures were studied. Thermodynamic analysis results showed that quartz and the chlorinating agent played key roles in the process of chlorination. Compared with KCl and NaCl, CaCl2 showed superiority in the chlorination. The phase transformation of sintering dust at different temperatures was analyzed. The volatilization rates of Pb and Cl reached 98.69 % and 84.55 %, respectively. The study of kinetics showed that the volatilization of PbCl2 was controlled by diffusion, and the apparent activation energy is 7.97 kJ/mol. Finally, chlorination roasting residue can be recycled for iron and steel metallurgy.

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.

Studies on the effective extraction and separation of zinc-iron from spent pickling solution using tri-n-octylamine (TOA) with solvent extraction were investigated. Single extraction efficiency of 83.75% is obtained under the optimal conditions (organic phase consisting of 30% (v/v) extractant TOA, 20% (v/v) modifier iso-octanol, and 50% (v/v) diluent sulfonated kerosene, organic phase volume: aqueous phase volume of 2:1, and extraction time 10 min), while only 1.8% iron is co-extracted. McCabe-Thiele diagram is employed to analyze the number of theoretical stages needed for the effective extraction of zinc, and it is found that under five-stage counter-current extraction, almost all the zinc ions are extracted. A stripping efficiency of more than 90% from the loaded organic phase is achieved by 2.0 mol/L NH3·H2O and organic phase volume: aqueous phase volume of 1:2. Furthermore, the extraction mechanism of zinc with TOA accompanied by anion exchange is demonstrated by FT-IR spectra analysis and ESI-MS analysis, and the structure of the extracted complex is confirmed as [ R 3 N H Z n C l 3 ] .

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.