Nickel recovery method was studied by the wet process from the catalyst used in hydrogenation process. Nickel content in waste catalyst was about 16%. At the waste catalyst leaching system by the alkaline solution, selective leaching of nickel was possible by amine complex formation reaction from ammonia water and ammonium chloride mixed leachate. The best leaching condition of nickel from mixed leachate was acquired at the condition of pH 8. LIX65N as chelating solvent extractant was used to recover nickel from alkaline leachate. The purity of recovered nickel was higher than 99.5%, and the whole quantity of nickel was recovered from amine complex.

In this study the optimum conditions for recovery of valuable metal in Electric Arc Furnace Dusts were investigated. 2M of H2SO4, 1~5 of solid/liquid ratio, 0~180 min of leaching time has been established for leaching condition, and for electrowinning, each of Pt, C, Zn, Pb anode and Zn, Cu cathode was compared respectively at pH 2, 4 and 6. The result of elemental analysis of Zn crystal, a lagre quantity of Fe and H has been observed with Zn and other heavy metal, therefore, impurities removing process would be requir for enhancing purity of Zn. As the result, about 60% of Zn has been recovered under condition of 2 M of H2SO4, 1:2 of S/L ratio at 120 min, and Pt or Pb for anode, Zn for cathode has been shown the highest efficiency of electrowinning at pH 6.

Hydrometallurgical process, which is one of the recycling method of EAFD in zinc, is a process to recover metallic crystal form that deposited on the cathod through electrolytic extraction by leaching valuable metals in appropriate solvent. Still, there is a lot of variable at electrowinning process, such as initial pH, space between electrode, voltage, current, cathod, or anode, Thus, many studies have been conducted previously. In this study, the consideration of optimistic condition in electrowinning process to recover the valuable metal in EAFD have been carried. The extraction amount by changing pH shows increase according to high initial pH, also, the alteration of extraction amount by controling the space between electrode, voltage or current has been measured. The difference of efficiency represent by decrease of electromotive force, sudden loss of voltage under specific condition, and using platinum as electrode shows most stable extraction. Furthermore, when distance between electrode are too close, the extracted zinc contact with anode, which make recovery difficult. The analysis result of zinc metallic crystal which been recovered draws spherical and cylindrical shapes are scattered and mixed, and consequence of EDX, content of zinc appear about 60%.