Settling separation process for nuetralized slurry and hydrometallurgical process for nickel oxide ore

Abstract

An object of the present invention is to provide a settling separation process for a neutralized slurry in which a neutralization step is efficiently performed for a leachate obtained by the leaching of nickel and cobalt from a nickel oxide ore, and further a neutralized precipitate obtained by precipitation of impurity components can effectively be separated and removed while inhibiting the filtration failure; and to provide a hydrometallurgical process for a nickel oxide ore, in which the above process is applied. In the present invention, a neutralization step is performed by using a magnesium oxide for a leachate obtained by the leaching of nickel and cobalt from a nickel oxide ore to obtain a neutralized slurry, and a neutralized precipitate is separated and removed by the addition of a cationic flocculant into the neutralized slurry.

1 . A settling separation process for a neutralized slurry obtained by performing a neutralization step for a leachate obtained by leaching of nickel and cobalt from a nickel oxide ore, comprising:
 performing a neutralization step for the leachate by using a magnesium oxide to obtain a neutralized slurry; and   separating and removing a neutralized precipitate by adding a cationic flocculant into the neutralized slurry.   
     
     
         2 . The settling separation process for a neutralized slurry according to  claim 1 , wherein
 the magnesium oxide is a magnesium oxide obtained by grinding a bed rock of the nickel oxide ore.   
     
     
         3 . The settling separation process for a neutralized slurry according to  claim 1 , wherein
 the leachate is a leachate obtained by leaching nickel and cobalt from the nickel oxide ore by a high-temperature high-pressure acid leaching process using a sulfuric acid solution.   
     
     
         4 . The settling separation process for a neutralized slurry according to  claim 1 , wherein
 an additive amount of the cationic flocculant is 650 to 1350 g/t (solid content) with respect to a solid content of a leach slurry.   
     
     
         5 . The settling separation process for a neutralized slurry according to  claim 1 , wherein
 an additive amount of the cationic flocculant is 900 to 1100 g/t (solid content) with respect to a solid content of a leach slurry.   
     
     
         6 . A hydrometallurgical process for a nickel oxide ore in which recovery of nickel and cobalt from a nickel oxide ore is performed by a high-temperature high-pressure acid leaching process containing a leaching step, a solid-liquid separation step and a neutralization step, the neutralization step, comprising:
 performing a neutralization step for a leachate obtained by leaching in the neutralization step using a magnesium oxide to obtain a neutralized slurry; and   adding a cationic flocculant into the neutralized slurry to separate and remove a neutralized precipitate.   
     
     
         7 . The hydrometallurgical process for a nickel oxide ore according to  claim 6 , wherein
 the magnesium oxide is a magnesium oxide obtained by grinding a bed rock of the nickel oxide ore.   
     
     
         8 . The hydrometallurgical process for a nickel oxide ore according to  claim 6 , wherein
 an additive amount of the cationic flocculant is 650 to 1350 g/t (solid content) with respect to a solid content of a leach slurry.   
     
     
         9 . The hydrometallurgical process for a nickel oxide ore according to  claim 6 , wherein
 an additive amount of the cationic flocculant is 900 to 1100 g/t (solid content) with respect to a solid content of a leach slurry.