| Project/Area Number |
12650736
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Metal making engineering
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| Research Institution | Kyushu Institute of Technology |
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Principal Investigator |
ITOU Hideyuki Faculty of Engineering, Kyushu Institute of Technology, Research Associate, 工学部, 助手 (90213074)
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| Co-Investigator(Kenkyū-buntansha) |
TAKASU Tomio Faculty of Engineering, Kyushu Institute of Technology, Associate Professor, 工学部, 助教授 (20264129)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2001: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2000: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | Elefctric Arc Furnace Dusts / Recycle / Zinc / Nitric Acid / Leaching / Electrowinning / Onsite process / Hydrometallurgy |
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| Research Abstract |
The purpose of this research is to develop a new process for the treatment of Electric Arc Furnace (EAF) dusts on site of the EAF works. Low concentration of nitric acid is selected to leach the zinc from the dust and to suppress the iron to leach. The residue is returned to the EAF as an iron source. The electrowinning recovers the zinc and reforms the acid.
(1) Electrowinning from nitric acid solution dissolved a pure zinc oxide
- The amount of deposited zinc corresponded to the quantity of electricity at the current density less than 400A/m2.
- The deposition was determined as ZnO which might be formed by the oxidation" during washing and drying before the analyses.
(2) Characterizations of the dusts and nitric acid leaching
- Zinc in the EAF dusts exists in the forms of ZnO and ZnFe2O4. The nitric acid solutions leached not only ZnO but also a part of ZnFe204.
- When the amount of EAF dust addition was large, iron concentration in the liquid was high in the initial stage and decreased with increase in pH due to dissolution of the zinc.
- A Pb leaching ratio was high when the amount of dust addition was small and decreased with increase in the amount of the addition. The ratio increased with increase of the nitric acid concentration.
(3) The electrowinning of zinc from the solution after leaching of the dust
- Formation of bubbles at the cathode was significant and the bubbles accumulated in the electrolyte.
- When the electrolyte was purified by using activated charcoal, the accumulation was suppressed though the bubble' is generated.
- Removal of dissolved silica from the electrolyte, by means of boiling and concentrating, increased the zinc concentration in the deposition from 12mass% to 54mass%, while gelatinous precipitation occurred.
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