Method for processing steelmaking dust, method for producing zinc, method for producing iron- and steelmaking raw material, and raw material of iron and steel

Abstract

[Object] To provide a method for processing steelmaking dust, a method for producing zinc, and a method for producing an iron- and steelmaking raw material, which are more advantageous than the Waelz method in terms of energy and economy. [Solving Means] A method for processing steelmaking dust according to an embodiment of the present invention includes: adding a calcium compound containing Ca to steelmaking dust containing zinc, the number of moles of Ca being equivalent to or more than the number of moles of Fe in the steelmaking dust; and heating and reducing, in a furnace, the steelmaking dust to which the calcium compound has been added. A ratio of the number of moles of Ca in the calcium compound to the number of moles of Fe in the steelmaking dust is adjusted to be not less than 1.3 and not more than 1.5.

1 . A method for processing steelmaking dust, comprising:
 adding a calcium compound containing Ca to steelmaking dust containing zinc, the number of moles of Ca being equivalent to or more than the number of moles of Fe in the steelmaking dust; and   heating and reducing, in a furnace, the steelmaking dust to which the calcium compound has been added, without generating melt.   
     
     
         2 . The method for processing steelmaking dust according to  claim 1 , wherein
 the calcium compound contains at least one of quicklime (CaO), hydrated lime (Ca(OH)2), and calcium carbonate (CaCO3).   
     
     
         3 . The method for processing steelmaking dust according to  claim 1 , wherein
 the step of adding the calcium compound to the steelmaking dust includes adjusting a ratio of the number of moles of Ca in the calcium compound to the number of moles of Fe in the steelmaking dust to be not less than 1.3 and not more than 1.5.   
     
     
         4 . The method for processing steelmaking dust according to  claim 1 , wherein
 the step of heating and reducing the steelmaking dust to which the calcium compound has been added includes adjusting a temperature in the furnace to be less than 1200° C.   
     
     
         5 . The method for processing steelmaking dust according to  claim 1 , wherein
 the step of adding the calcium compound to the steelmaking dust includes further adding a carbon material to the steelmaking dust.   
     
     
         6 . The method for processing steelmaking dust according to  claim 1 , wherein
 the step of heating and reducing the steelmaking dust to which the calcium compound has been added includes adding reducing gas to an inside of the furnace.   
     
     
         7 . The method for processing steelmaking dust according to  claim 1 , wherein
 the furnace is a rotary kiln, a rotary hearth, or a shaft furnace.   
     
     
         8 . A method for producing zinc, comprising:
 adding a calcium compound containing Ca to steelmaking dust containing zinc, the number of moles of Ca being equivalent to or more than the number of moles of Fe in the steelmaking dust,   heating and reducing, in a furnace, the steelmaking dust to which the calcium compound has been added, without generating melt, and   recovering a zinc component therefrom.   
     
     
         9 . The method for producing zinc according to  claim 8 , wherein
 the step of adding the calcium compound to the steelmaking dust includes adjusting a ratio of the number of moles of Ca in the calcium compound to the number of moles of Fe in the steelmaking dust to be not less than 1.3 and not more than 1.5.   
     
     
         10 . The method for producing zinc according to  claim 8 , wherein
 the step of heating and reducing the steelmaking dust to which the calcium compound has been added includes adjusting a temperature in the furnace to be less than 1200° C.   
     
     
         11 . A method for producing an iron- and steelmaking raw material, which separates zinc from steelmaking dust to recover zinc as the iron- and steelmaking raw material, the method comprising:
 adding a calcium compound containing Ca to steelmaking dust containing zinc, the number of moles of Ca being equivalent to or more than the number of moles of Fe in the steelmaking dust,   heating and reducing, in a furnace, the steelmaking dust to which the calcium compound has been added, without generating melt, and   separating zinc from the steelmaking dust.   
     
     
         12 . The method for producing an iron- and steelmaking raw material according to  claim 11 , wherein
 the step of adding the calcium compound to the steelmaking dust includes adjusting a ratio of the number of moles of Ca in the calcium compound to the number of moles of Fe in the steelmaking dust to be not less than 1.3 and not more than 1.5.   
     
     
         13 . The method for producing an iron- and steelmaking raw material according to  claim 11 , wherein
 the step of heating and reducing the steelmaking dust to which the calcium compound has been added includes adjusting a temperature in the furnace to be less than 1200° C.   
     
     
         14 . A raw material of iron and steel, comprising:
 zinc whose amount is not more than 0.1% by weight; and   dicalcium ferrite (2CaO.Fe2O3) whose amount (% by weight) is large and iron (II) oxide (FeO) whose amount (% by weight) is small.