Yu Xianjin

Recovery of zinc, lead and silver from zinc leaching residue

A two-stage process of recovery of zinc-lead-silver from zinc leaching residue was investigated. The stage of sulfated roasting-water leaching of zinc leaching residue was applied to recovery zinc by controlling sulfuric acid dosage, roasting time and temperature, leaching time, the ratio of L/S and the addition of sodium chloride. The second stage is chloride leaching of the residual solid after zinc extraction to recovery lead and silver. The concentration of NaCl, leaching time and temperature, the ratio of L/S and the dosage of hydrochloric acid were studied. The optimum conditions of metals extraction are determined and the optimal rate of zinc 81%, lead 95%, silver 70% are obtained.

Preparation and properties of Al-Mn alloy coatings in NaCl-KCl-AlCl3-CeCl3 molten salts

Al-Mn alloy coatings were electrodeposited on an iron substrate from AlCl3-NaCl-KCl molten salts with anhydrous MnC12 enhanced by the addition of CeCl3.The microstructure and properties of the Al-Mn alloy coatings were investigated,and scanning electron microscopy,X-ray diffraction,and polarization curves were used to determine the composition,surface morphology,phase structure,and corrosion resistance of the obtained deposits.The results showed that the surface coatings were smooth,and that the crystallites were dense and uniform when 0.22 wt.％ CeCl3 was added to the molten salt.An amorphous mixture of Al and Al6Mn was obtained.CeCl3 enhanced the corrosion resistance and increased the hardness of the single amorphous phase alloys.The pitting potential of the coating was approximately -1.1239 V,and its hardness was 390 kgf/mm2.

Recovery of alumina from sodium hydrate alumino-silicate by a novel hydrometallurgical route

A great amount of sodium hydrate alumino-silicate generated from alumina production not only threatens the environment but also causes waste of secondary resources. High-alumina-content sodium hydrate alumino-silicate was employed to recover alumina by the process of hydrometallurgical route at low temperature and normal atmosphere. The X-ray diffraction pattern shows sodium hydrate alumino-silicate was completely decomposed and was converted into sodium riopone and dawsonite. Experimental results indicate that A/S of tailings can reach 0.53, respectively under the optimized conditions.

Corrosion of Zinc Ferrite Based Inert Anodes in AlF3-NaF-Al2O3 Melts Under Conditions of Anodic Polarization

Abstract ZnFe2O4-based inert anodes were made to conduct the aluminum electrolysis tests. The corrosion behaviors of the inert anodes were examined and discussed. Experiment results prove that: (1) ZnFe2O4-based inert anodes are good corrosion resistant to AlF3-NaF-Al2O3 melts under the conditions of anodic polarization; (2) High anodic current density (> 1.5 A·cm−2), high alumina concentration and low ratio of NaF/AlF3 in the molten salts will be the most important conditions for using inert anode.