| Summary: | 碩士 === 國立屏東科技大學 === 環境工程與科學系 === 94 === The waste could be regard as resource wrongly disposed. When the reusable value of waste is higher than the handling charge could it be seen as resource. The ultimate goal of waste management is sustainable used by efficiently/economically resources recycle.
The production of hazardous heavy metal sludge in Taiwan has reached 820,000 tons per year. Sludge disposal technologies such as solidification and landfill are irrelevantly. Therefore, this study is conducted by the procedures of acid extraction-chemical cementation and acid extraction-fractional precipitation to recovery copper from copper sludge of printed circuit board industry.
Analysis data shows that copper in sludge is around 19%, followed are Ni, Pb, Zn, Cd, Cr, and Fe. The acid extraction results shows the best extraction conditions are found by 2N H2SO4(aq) and HNO3(aq) in solid-liquid ratio 1:10 for 0.5小時. Moreover heavy metals in residues after 2N H2SO4(aq) and distilled water extraction can reach the TCLP standards, and can be look as general industrial wastes for landfill. But the Pb and Cd in residues after the same processes are higher than the TCLP standards, and must be treated further again.
The chemical cementation experimental results show that after 2N H2SO4(aq), HNO3(aq) extraction and followed by Fe and Zn displacement, about 93-100% Cu can be displaced. Moreover copper purity are about 44-50% 72-75% by using Fe and Zn as displacement metals, respectively.
The fractional precipitation experimental results show that the purity of recovered anhydrous CuSO4(s) high to 85% after three times precipitating purified by 2N H2SO4(aq) extraction solution.
The cost-benefit analysis indicates that using the procedures of acid extraction-chemical cementation and acid extraction-fractional precipitations for copper-containing sludge are feasible. The process must be of great helped to the environment and resource sustainable used.
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