Method for eluting calcium from steelmaking slag, and method for collecting calcium from steelmaking slag

Abstract

The purpose of the present invention is to provide a method for eluting Ca from steelmaking slag such that a large amount of Ca can be eluted from the steelmaking slag into an aqueous solution containing carbon dioxide. The present invention executes, in this order: a step for removing an iron-containing compound from steelmaking slag by performing magnetic separation on the steelmaking slag; and a step for bringing the steelmaking slag subjected to magnetic separation into contact with an aqueous solution containing carbon dioxide. In addition, the aqueous solution containing carbon dioxide and the steelmaking slag are brought into contact with each other while the steelmaking slag is being pulverized or the surface of the steelmaking slag is being ground.

1 . A method for eluting calcium from steelmaking slag, the method comprising:
 subjecting the steelmaking slag to magnetic separation to remove a compound containing iron from the steelmaking slag; and   contacting the steelmaking slag subjected to the magnetic separation with an aqueous solution containing carbon dioxide.   
     
     
         2 . The method according to  claim 1 , wherein the contacting includes contacting the steelmaking slag with the aqueous solution containing carbon dioxide while fracturing or pulverizing the steelmaking slag, or grinding a surface of the steelmaking slag. 
     
     
         3 . The method according to  claim 1 , further comprising:
 subjecting the steelmaking slag to hydration treatment, and   wherein the contacting includes contacting the steelmaking slag subjected to the magnetic separation and the hydration treatment with the aqueous solution containing carbon dioxide.   
     
     
         4 . The method according to  claim 3 , wherein the hydration treatment is performed before the magnetic separation. 
     
     
         5 . The method according to  claim 3 , wherein the hydration treatment is performed after the magnetic separation. 
     
     
         6 . The method according to  claim 3 , wherein the hydration treatment is performed simultaneously with the magnetic separation. 
     
     
         7 . The method according to  claim 1 , further comprising:
 subjecting the steelmaking slag to heat treatment before performing the magnetic separation.   
     
     
         8 . A method for recovering calcium from steelmaking slag, the method comprising:
 eluting the calcium from the steelmaking slag by the method according to  claim 1 ; and   recovering the eluted calcium.