Zinc production method
AssigneeKinotech Solar Energy Corporation
InventorsMasaaki Iosaki, Shuji Mori
Life of this patent
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Abstract
A zinc production method includes a reaction step such as a leaching step (101) of bringing electric arc furnace dust (1) containing zinc oxide or the like into contact with a chlorine gas (8) to obtain a zinc oxide component in the electric arc furnace dust (1) or the like as crude zinc chloride (3), a purification step (102) of heating the crude zinc chloride (3) obtained at the reaction step to produce zinc chloride vapor, and cooling and condensing the zinc chloride vapor, thereby obtaining purified zinc chloride (6), and an electrolysis step (103) of electrolyzing the purified zinc chloride (6) obtained at the purification step (102) in a molten state to obtain a zinc melt (9) and the chlorine gas (8).
Claims14
A zinc production method comprising:
- a reaction step of obtaining crude zinc chloride from a zinc oxide component in electric arc furnace dust containing zinc oxide or in secondary dust generated at a time of reducing the electric arc furnace dust in a reduction furnace;
- a purification step of heating the crude zinc chloride obtained at the reaction step to produce zinc chloride vapor, and cooling and condensing the zinc chloride vapor, thereby obtaining purified zinc chloride;
- and
- an electrolysis step of electrolyzing the purified zinc chloride obtained at the purification step in a molten state to obtain a zinc melt and a chlorine gas,
- wherein the reaction step includes a leaching step of bringing the electric arc furnace dust or the secondary dust into contact with a chlorine gas to extract a zinc oxide component in the electric arc furnace dust or in the secondary dust as crude zinc chloride by blowing the chlorine gas into the molten zinc chloride bath in which the electric arc furnace dust or secondary dust is dispersed and immersed,
- wherein, in the reaction step, metal components are contained in the electric arc furnace dust or the secondary dust, a part of the metal components, excluding a zinc component in the electric arc furnace dust or in the secondary dust, is extracted together with the zinc component and mixed in the crude zinc chloride as a metal chloride component, and a remainder of the metal components is separated as a residue,
- and wherein, in the purification step, the metal chloride component has a lower boiling point than that of zinc chloride and gasifies earlier than the zinc chloride to separate from the zinc chloride vapor, and a remaining metal chloride component having a higher boiling point than that of the zinc chloride remains as liquid after the zinc chloride has gasified to be separated from the zinc chloride vapor.
A zinc production method comprising:
- a reaction step of obtaining crude zinc chloride from a zinc oxide component in electric arc furnace dust containing zinc oxide or in secondary dust generated at a time of reducing the electric arc furnace dust in a reduction furnace;
- a purification step of heating the crude zinc chloride obtained at the reaction step to produce zinc chloride vapor, and cooling and condensing the zinc chloride vapor, thereby obtaining purified zinc chloride;
- and
- an electrolysis step of electrolyzing the purified zinc chloride obtained at the purification step in a molten state to obtain a zinc melt and a chlorine gas, wherein
- the reaction step includes:
- a leaching step of bringing the electric arc furnace dust or the secondary dust into contact with an aqueous solution of an alkaline agent to turn a zinc oxide component in the electric arc furnace dust or in the secondary dust into zinc hydroxide, thereby obtaining a leaching solution containing the zinc hydroxide,
- a crystallization step of precipitating and settling the zinc hydroxide from the leaching solution obtained at the leaching step, and separating and recovering the zinc hydroxide therefrom as a solid, and
- a chlorination step of bringing the zinc hydroxide separated and recovered at the crystallization step into contact with hydrochloric acid to obtain crude zinc chloride, and
- further includes a drying step of bringing the crude zinc chloride obtained at the chlorination step into contact with a chlorine gas, after heating the crude zinc chloride to separate water contained in the crude zinc chloride therefrom as water vapor, and
- at the purification step, the crude zinc chloride having undergone the drying step is heated.
Dependencies are inferred from the claim text.