| Summary: | 碩士 === 國立高雄大學 === 應用化學系碩士班 === 108 === This study focused on aluminum ion extraction from the “aluminum-containing alkaline waste liquid” produced by aluminum extrusion plants. Aluminum ion from industrial wastewater were used to synthesize hydrotalcite (Layered Double Hydroxide, LDH) with hydrothermal method, at the same time, the “purified” industrial alkaline waste liquid can be recycled back to the aluminum extrusion production process. Our method achieves both reducing the wastewater in plant and recycling the waste aluminum by forming LDH.
In this study, the synthetic condition of LDH is much different from the usual laboratory preparation process, hence, acidic magnesium source was used to synthesize LDH, which confirmed the feasibility of directly synthesizing Mg Al LDH from high concentration waste liquid, thus improving the practicability. Experimental results show that between the temperature of 75 - 150C, magnesium nitrate and magnesium acetate can successfully synthesize LDH. When LDH was synthesized at 75 ° C for 12 hours, the aluminum recovery is 99%. Experimental results show that the solution concentration will reduce the crystallization rate. The recovery of aluminum was 98 and 99% by using magnesium nitrate with hydrothermal synthesis at 6 ° C for 6 and 12 hours respectively. Experimental results show that the recovered alkali solution can further dissolve aluminum, but ability of dissolving aluminum is lower than that of the newly prepared sodium hydroxide solution, therefore, the NaOH solution can be supplied to the “purified alkaline solution” to increase its aluminum-dissolving efficiency.
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