Zinc production method using electric furnace dust as raw material

Abstract

A zinc production method including a chlorination step 101 at which crude zinc chloride vapor 3 and an oxygen gas 2 are obtained by bringing electric furnace dust 1 containing zinc oxide or secondary dust 1 generated at the time of reducing the electric furnace dust in a reduction furnace into contact with a mixed gas containing a chlorine gas 8 and an oxygen-containing gas 10, converting a zinc oxide component in the electric furnace dust 1 or the secondary dust 1 into zinc chloride, and vaporizing the zinc chloride. The zinc production method further includes purification steps 102, 104, and 105 at which a zinc chloride component contained in the crude zinc chloride vapor 3 is separated from components 5 and 7 other than zinc chloride contained in the crude zinc chloride vapor 3 to obtain a purified zinc chloride melt 6, and an electrolysis step 103 at which the purified zinc chloride melt 6 is electrolyzed to obtain a zinc melt 9 and the chlorine gas 8.

Description

TECHNICAL FIELD[0001]The present invention relates to a zinc production method, and more particularly relates to a zinc production method using, as a raw material, electric furnace dust generated at the time of melting and refining of scraps in an electric furnace method, being one of iron-making processes, or dust generated in a reduction furnace at the time of recycling electric furnace dust as an iron-making raw material, a non-ferrous material, or a cement extender (hereinafter, “secondary dust”).BACKGROUND ART[0002]Generally, in the electric furnace method, being one of the iron-making processes, electric furnace dust is generated as industrial waste containing zinc oxide components in an amount of about 1.5% to 2.0% of steel production at the time of melting and refining of scraps. It is reported that 7 million tons of electric furnace dust are generated globally, and 0.5 million tons of electric furnace dust are generated in Japan.[0003]Most of iron scraps are from discarded ...

AI Technical Summary

Benefits of technology

[0033]According to the zinc production method of the first aspect of the present invention, the zinc oxide component can be preferentially chlorinated at the chlorination step, without chlorinating most of the iron oxide component and free iron oxide present singly in zinc ferrite. At the distillation purification step, the zinc chloride component contained in the crude zinc chloride vapor obtained at the chlorination step is separated from components other than zinc chloride contained in the crude zinc chloride vapor, thereby enabling to obtain a purified zinc chloride melt. At the electrolysis step, the molten salt electrolysis method can be performed by using the purified zinc chloride melt obtained at the purification step. Accordingly, it is possible to realize the zinc production method that is suitable for treatment of electric furnace dust or the like containing chlorine in a large amount without requiring any additional cost for dechlorination, can produce zinc bare metal having a high purity of 4N or more, and can be operated with a compact apparatus.

[0034]According to the zinc production method of the second aspect of the present invention, at the distillation purification step, zinc chloride and metal chloride other than the zinc chloride are separated from each other by using a vapor pressure difference therebetween, and the zinc chloride component contained in the crude zinc chloride vapor can be purified. Accordingly, purified zinc chloride can be obtained easily and efficiently.

[0035]According to the zinc production method of

Problems solved by technology

Therefore, the electric furnace dust contains hazardous organic matter such as chloride and dioxin, in addition to heavy metals such as zinc and lead.

However, it is difficult to directly use the electric furnace dust as a

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