Hydrometallurgical process for recovery of nickel and cobalt

Abstract

The present invention is related to a hydrometallurgical process to produce nickel as hydroxide, oxide or cathode and produce cobalt preferably as sulfides. The present invention is particularly adequate to process eluate containing nickel and cobalt. Eluates are solutions obtained from elution of ionic exchange resins, loaded (charged) in the RIP (resin-in-pulp) process of ionic exchange, to recover nickel and cobalt from effluent pulps in acid leaching. Following nickel and cobalt recovery in a RIP circuit, they are separated from each other via a continuous ionic exchange process, after which the nickel eluate is formed to produce nickel as nickel oxide by a pyrohydrolysis process.

1 . A hydrometallurgical process for recovery of nickel and cobalt applicable to a pulp resulting from lateritic ore leaching, nickel oxidate, cobalt oxidate or a mixture with nickel and cobalt as metals of interest, and other secondary metals regarded as impurities such as manganese, magnesium, calcium, aluminum, iron and chromium wherein the pulp was previously processed with a) possible pH adjustment aided by acid or base, and, simultaneously, an optimal and selective loading of nickel and cobalt in the resin, b) leached pulp contacts ionic exchange resin, in a RIP process, c) loaded resin is separated from pulp via screening, d) nickel and cobalt eluted from resin, to form eluate bearing nickel soluble salt and cobalt soluble salt as well as impurities, e) possible reduction of soluble impurity species or use of cementing/complexation techniques, f) eluate obtained contacts ionic exchange resin, to load nickel in resin and remaining cobalt in raffinate, g) nickel-bearing resin is separated from raffinate concentrate in cobalt, h) nickel-bearing resin is eluated in acid solution, and wherein the hydrometallurgical process comprises precipitating the cobalt selected from the group consisting of sulfide, hydroxide and carbonates, and recovering the nickel selected from the group consisting of a precipitate in the form of hydroxide, electro-recovered as cathode nickel and nickel oxide via pyrohydrolysis at relatively high temperatures and with HCl regeneration. 
     
     
         2 . The process, according to  claim 1  wherein the pyrohydrolysis is carried out at temperatures above about 727° C. 
     
     
         3 . The process according to  claim 1  wherein HCl is recovered as a high-purity acid. 
     
     
         4 . The process according to  claim 3  wherein the recovery of HCl is about 99%. 
     
     
         5 . The process according to  claim 1  wherein HCl is reused in the resin elution. 
     
     
         6 . The process according to  claim 1  wherein a concentrated NiCl 2  solution is produced. 
     
     
         7 . The process according to  claim 6  wherein the solution undergoes pyrohydrolysis, generating NiO and HCl. 
     
     
         8 . The process according to  claim 6  wherein the solution undergoes electrolysis, generating metallic nickel and chloride gas.