Hydrometallurgical plant for nickel oxide ore and method for operating the hydrometallurgical plant

Abstract

A hydrometallurgical plant according to the invention includes: a leaching facility provided with leaching treatment tanks in a plurality of lines to perform a leaching treatment; a preliminary neutralization facility provided with neutralization treatment tanks in two stages to perform pH adjustment of leach slurry; and solid-liquid separation facility made up of a single line to perform solid-liquid separation of leach slurry which is pH-adjusted and discharged from the preliminary neutralization facility, in which the preliminary neutralization facility is provided with neutralization treatment tanks of a first stage in a plurality of lines so as to correspond to the respective leaching treatment tanks, and is configured such that leach slurries which are pH-adjusted in the neutralization treatment tanks of the first stage are merged in a neutralization treatment tank 1 of a second stage made up of a single line, and merged leach slurry is transported to the solid-liquid separation facility.

1 . A hydrometallurgical plant for nickel oxide ores, comprising at least:
 a leaching facility provided with leaching treatment tanks in a plurality of lines to apply a leaching treatment to a nickel oxide ore;   a preliminary neutralization facility provided with neutralization treatment tanks in two stages to perform preliminary neutralization by which pH of leach slurry discharged from the leaching treatment tanks is adjusted to a predetermined range; and   a solid-liquid separation facility made up of a single line to perform solid-liquid separation of leach slurry pH-adjusted and discharged from the preliminary neutralization facility into a leachate and a leach residue in a solid-liquid separation tank,   wherein the preliminary neutralization facility is configured such that neutralization treatment tanks of a first of the two stages are provided in a plurality of lines so as to correspond to the respective lines of the leaching treatment tanks provided in the leaching facility, and leach slurries which are pH-adjusted in the neutralization treatment tanks of the first stage in the respective lines are merged in a neutralization treatment tank of a second of the two stages which is made up of a single line, and leach slurry merged in the neutralization treatment tank of the second stage is transported to the solid-liquid separation facility.   
     
     
         2 . The hydrometallurgical plant for nickel oxide ores according to  claim 1 ,
 wherein piping to connect each of the neutralization treatment tanks of the first stage to an inlet portion of a corresponding one, arranged in the same line, of the leaching treatment tanks in the leaching facility, is provided and   wherein leach slurry or a process liquid discharged from each of the neutralization treatment tanks of the first stage is enabled to be circulated to a corresponding one, arranged in the same line, of the leaching treatment tanks in the leaching facility.   
     
     
         3 . The hydrometallurgical plant for nickel oxide ores according to  claim 1 , further comprising:
 a final neutralization facility to apply a neutralization treatment to a leach residue obtained by solid-liquid separation in the solid-liquid separation facility; and   piping to connect the neutralization treatment tanks of the first stage to an inlet portion of the final neutralization facility, and   wherein leach slurry discharged from the neutralization treatment tanks of the first stage is enabled to be transported to the final neutralization facility.   
     
     
         4 . The hydrometallurgical plant for nickel oxide ores according to  claim 1 , wherein the solid-liquid separation facility is provided with solid-liquid separation tanks in multiple stages to perform solid-liquid separation of leach slurry discharged from the neutralization treatment tanks with multistage washing. 
     
     
         5 . The hydrometallurgical plant for nickel oxide ores according to  claim 4 ,
 wherein piping to connect the neutralization treatment tanks of the first stage to an inlet portion of each of the solid-liquid separation tanks provided in multiple stages in the solid-liquid separation facility is provided, and   wherein leach slurry discharged from the neutralization treatment tanks of the first stage is enabled to be transported to the solid-liquid separation tanks.   
     
     
         6 . The hydrometallurgical plant for nickel oxide ores according to  claim 1 , wherein a production amount of leach slurry in the leaching facility is from 10,000 tons/year to 20,000 tons/year in terms of nickel amount. 
     
     
         7 . A method for operating a hydrometallurgical plant for nickel oxide ores to recover nickel and cobalt from a nickel oxide ore,
 wherein the hydrometallurgical plant for nickel oxide ores comprises at least:
 a leaching facility provided with leaching treatment tanks in a plurality of lines to apply a leaching treatment to a nickel oxide ore; 
 a preliminary neutralization facility provided with neutralization treatment tanks in two stages to perform preliminary neutralization by which pH of leach slurry discharged from the leaching treatment tanks is adjusted to a predetermined range; and 
 a solid-liquid separation facility made up of a single line to perform solid-liquid separation of leach slurry pH-adjusted and discharged from the preliminary neutralization facility into a leachate and a leach residue in a solid-liquid separation tank, 
   wherein, in the preliminary neutralization facility, neutralization treatment tanks of a first of the two stages are provided in a plurality of lines so as to correspond to the respective lines of the leaching treatment tanks provided in the leaching facility, and a neutralization treatment tank of a second of the two stages is made up of a single line, and   wherein leach slurries discharged from the respective neutralization treatment tanks of the first stage are merged in the neutralization treatment tank of the second stage made up of a single line, and merged leach slurry is transported to the solid-liquid separation facility.   
     
     
         8 . The method for operating a hydrometallurgical plant for nickel oxide ores according to  claim 7 ,
 wherein piping to connect each of the neutralization treatment tanks of the first stage to an inlet portion of a corresponding one, arranged in the same line, of the leaching treatment tanks in the leaching facility is provided, and   wherein, at a stage immediately after operation start, leach slurry or a process liquid discharged from the leaching treatment tanks is circulated from the neutralization treatment tanks of the first stage to the leaching treatment tanks via the piping.   
     
     
         9 . The method for operating a hydrometallurgical plant for nickel oxide ores according to  claim 7 , wherein the solid-liquid separation facility is provided with solid-liquid separation tanks in multiple stages to perform solid-liquid separation of a leachate discharged from the neutralization treatment tanks with multistage washing. 
     
     
         10 . The method for operating a hydrometallurgical plant for nickel oxide ores according to  claim 9 ,
 wherein the hydrometallurgical plant further comprises: a final neutralization facility to apply a neutralization treatment to a leach residue obtained by solid-liquid separation in the solid-liquid separation facility; and piping to connect the neutralization treatment tanks of the first stage to an inlet portion of the final neutralization facility, and   wherein, when a nickel concentration of leach slurry discharged from the leaching treatment tanks is lower than a nickel concentration of a leachate in a solid-liquid separation tank of a last of the multiple stages in the solid-liquid separation facility, the leach slurry discharged from the leaching treatment tanks is transported from the neutralization treatment tank of the first stage to the final neutralization facility via the piping.   
     
     
         11 . The method for operating a hydrometallurgical plant for nickel oxide ores according to  claim 9 ,
 wherein piping to connect the neutralization treatment tanks of the first stage to an inlet portion of each of the solid-liquid separation tanks provided in multiple stages in the solid-liquid separation facility is provided, and   wherein, when a nickel concentration of leach slurry discharged from the leaching treatment tanks is lower than a desired nickel concentration of a leachate to be transported to the neutralization treatment tank of the second stage, the leach slurry discharged from the leaching treatment tanks is transported from the neutralization treatment tanks of the first stage to a solid-liquid separation tank of a predetermined stage via the piping.