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.

To develop managing guidance of occupational noise exposure for metal working facility, we have studied about drafting contour map of noise exposure, methods of noise assessment and actual calculation method of time weighted noise exposure. Therefore we have suggested that contour maps of noisy workplace are very important for controlling metal working fluid facility and two kinds of noise assessment method, so called, personal and static exposure are necessary to avoid argument between workers and managing group. Finally we would like recommend that the Korean specfication of noise exposure should be modified to protect ONIHL(occupational noise induced hearing loss).