Method and apparatus for regeneration of extraction solution in metal extraction processes

Abstract

A method and apparatus for restoring the extractive potential of organic hydroxyoxime-based extraction solution used in the recovery of metals by liquid-liquid extraction are provided. The method is two-stage, in which an aqueous solution of hydroxylamine or some hydroxylamine compound is used in the reaction stage, and the removal of the undesirable compounds generated in the reaction occurs in the second stage by adsorption purification. The reaction stage and the adsorptive stage are carried out in a mixing tank.

1 . An apparatus for treating organic extraction solution used in liquid-liquid extraction, where the extraction reagent of the solution is hydroxyoxime-based and where the metal extraction properties of said solution have been changed chemically in the process conditions, wherein in order to restore the physical and metal extraction properties of the extraction solution said solution is treated in two stages, whereby in the first of which, the reaction stage, the mixing of the extraction solution to be reoximated and an aqueous solution of hydroxylamine or a compound thereof, takes place in a mixing tank, which is equipped with a spiral-shaped mixer, after which the solutions are separated from each other and the extraction solution is treated in an adsorption purification stage mixing tank, in which the mixing of the extraction solution and some adsorption material in solid form is carried out with a spiral-shaped mixer. 
     
     
         2 . An apparatus according to  claim 1 , wherein a pH electrode is installed in the apparatus for measuring the pH value of the aqueous hydroxylamine solution. 
     
     
         3 . An apparatus according to  claim 1 , wherein a pH electrode is installed in the mixing tank. 
     
     
         4 . An apparatus according to  claim 1 , wherein the apparatus comprises one mixing tank, whereby both the reaction stage and the adsorption stage are implemented in the same mixing tank. 
     
     
         5 . An apparatus according to  claim 1 , wherein the apparatus comprises two mixing tanks: a reaction stage mixing tank and an adsorption stage mixing tank. 
     
     
         6 . An apparatus according to  claim 1 , wherein the apparatus comprises at least one mixing tank and at least one settling tank connected to it. 
     
     
         7 . An apparatus according to  claim 1 , wherein the settling tank acts as the extraction solution storage tank. 
     
     
         8 . An apparatus according to  claim 1 , wherein the apparatus includes members for recycling the aqueous solution from the reaction stage settling tank to the reaction stage mixing tank.