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.

1 . A zinc production method comprising:
 a chlorination step of obtaining crude zinc chloride vapor by bringing electric furnace dust containing zinc oxide or secondary dust generated at a time of reducing the electric furnace dust in a reduction furnace into contact with a mixed gas containing a chlorine gas and an oxygen-containing gas, converting a zinc oxide component in the electric furnace dust or the secondary dust into zinc chloride, and vaporizing the zinc chloride;   a purification step of obtaining purified zinc chloride by separating a zinc chloride component contained in the crude zinc chloride vapor from components other than zinc chloride contained in the crude zinc chloride vapor; and   an electrolysis step of obtaining a zinc melt and a chlorine gas by electrolyzing a molten salt electrolytic bath in which the purified zinc chloride is melted.   
     
     
         2 . The zinc production method according to  claim 1 , wherein the purification step includes a distillation purification step of obtaining the purified zinc chloride by distilling a melt containing the zinc chloride component contained in the crude zinc chloride vapor. 
     
     
         3 . The zinc production method according to  claim 1 , wherein the purification step includes a reduction purification step of obtaining the purified zinc chloride by adding a reducing agent to a melt containing the zinc chloride component contained in the crude zinc chloride vapor. 
     
     
         4 . The zinc production method according to  claim 1 , wherein the purification step includes a distillation purification step of obtaining primary purified zinc chloride by distilling a melt containing the zinc chloride component contained in the crude zinc chloride vapor and a reduction purification step of obtaining secondary purified zinc chloride by adding a reducing agent to a melt of the primary purified zinc chloride obtained at the distillation step. 
     
     
         5 . The zinc production method according to  claim 1 , wherein the chlorine gas is obtained by electrolysis at the electrolysis step. 
     
     
         6 . The zinc production method according to  claim 1 , wherein air is used as the oxygen-containing gas. 
     
     
         7 . The zinc production method according to  claim 3 , wherein the reducing agent is powdered metal zinc. 
     
     
         8 . The zinc production method according to  claim 3 , wherein at the reduction purification step, the reducing agent is added to molten salt in which the zinc chloride component contained in the crude zinc chloride vapor and alkali chloride or alkaline earth chloride are mixed and melted. 
     
     
         9 . The zinc production method according to  claim 1 , wherein at the electrolysis step, the molten salt electrolytic bath in which the purified zinc chloride and alkali chloride or alkaline earth chloride are mixed and melted is electrolyzed.