Title page for etd-0729118-132832


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URN etd-0729118-132832
Author Tien-Sheng Liu
Author's Email Address No Public.
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Department Environmental Engineering
Year 2017
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Feasibility of using phosphoric acid for extraction of aluminum oxide from furnace dust
Date of Defense 2018-07-25
Page Count 101
Keyword
  • Aluminium-containing ash
  • Aluminium oxide
  • Reaction time
  • Phosphoric acid
  • Acid process
  • Temperature
  • Abstract Aluminum smelting is one critical process in the aluminum-regeneration industries. In Taiwan, the production of aluminum-containing dusts produced by smelting exceeds 100,000 tons/year. The principal constituents in aluminum-containing dusts include metal aluminum, aluminum oxide, aluminum nitride, and aluminum carbide. By effectively recycling and reusing aluminum-containing dusts, elevating the aluminum recovery of the processes, and increasing the feasibility of producing aluminum oxide-containing produces, the land area and cost needed for the aluminum-containing solid waste treatments can be critically reduced, simultaneously increasing the value of the end-point products. The objective of this study was to study the effectiveness and efficiency of extracting aluminum from the aluminum-containing dusts by using the acid process with phosphoric acid, with respect to the effects of temperature and time for calcination. The sub-topics are to test: a) the effect of filtration on the recovery and concentration of aluminum oxide in the products when water was used for aluminum dissolution; b) the effect of solid-to-water mass ratio on the recovery and concentration of aluminum oxide in the products when water was used for aluminum dissolution; c) the effect of solid-to-sodium hydroxide mass ratio on the recovery and concentration of aluminum oxide in the products when sodium hydroxide was used for aluminum dissolution; d) the effect of the solid-to-sodium hydroxide mass ratio and the amount of sodium hydroxide on the recovery and concentration of aluminum oxide in the products when sodium hydroxide was used for aluminum dissolution; e) the effect of different stirring approaches on the recovery and concentration of aluminum oxide in the products; and f) the feasibility of using phosphoric acid for extraction of aluminum oxide from aluminum-containing ashes.
    In the results, aluminum oxide was mostly present in the solid residue after the reactions. Given the low solubility of aluminum, the addition of base is inevitable for dissolution of aluminum oxide. The recovery of aluminum oxide in the solid residue ranged from 70% to 90%, suggesting that most of the aluminum oxide was still present in the solid residue instead of the supernatant. The performance of this extraction process was better when high-temperature calcination was used for aluminum dissolution with phosphoric acid. To reach the highest aluminum oxide content in the products, the optimal parameters are as follows: 2 g of aluminum-containing ash was collected. The solid-to-phosphoric acid mass ratio was 1 to 0.49. The calcination temperature and time were 275℃ and 2.5 hr, respectively. 1.2 g of sodium hydroxide was added and the reaction was maintained at 85℃ for 0.5 hr. The solid and solution were separated, followed by drying the solid residue at a high temperature. The concentration and recovery of aluminum oxide in the product through this approach were 59.6% and 97.5%, respectively. To reach the highest aluminum oxide recovery, the optimal parameters are as follows: 2 g of aluminum-containing ash was collected. The solid-to-phosphoric acid mass ratio was 1 to 0.49. The calcination temperature and time were 275℃ and 2.5 hr, respectively. 0.8 g of sodium hydroxide was added and the reaction was maintained at 85℃ for 0.5 hr. The solid and solution were not separated, followed by drying the solid residue at high temperature. The concentration and recovery of aluminum oxide in the product through this approach were 36.7% and 106.6%, respectively. In the future study, the effective and efficient removal of the phosphor from the final product is the key to develop this extraction technology.
    Advisory Committee
  • Chin-Hsing Lai - chair
  • Pai-Haung Shih - co-chair
  • Wei-Hsien Chen - advisor
  • Files
  • etd-0729118-132832.pdf
  • Indicate in-campus at 5 year and off-campus access at 5 year.
    Date of Submission 2018-08-29

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