Direct Solvent Extraction of Nickel from Sulfuric Acid Leach Solutions of Low Grade and Complicated Nickel Resources Using a Novel Extractant of HBL110

Abstract

A new process of direct solvent extraction of nickel from sulfuric acid leach solutions of low grade and complicated nickel resources using a novel extractant HBL110 was proposed. The basic performance of new organic system was investigated and the continuous pilot plant and the industrial test were conducted. The results indicated that the extractant of HBL110 can be used to directly extract nickel selectively over iron, aluminum, manganese, magnesium, calcium and chromium from sulfuric acid leach solutions. The loaded organic solution can be easily stripped using dilute H₂SO₄ solutions. Both kinetics of extraction and stripping of nickel were fast. The continuous pilot plant test with the sulfuric acid leach solution of laterite containing 6.22g/L Ni²⁺, 14.1g/L Fe³⁺, 0.73g/L Fe²⁺, 33.9g/L Mg²⁺, 1.58g/L Al³⁺, 0.495g/L Ca²⁺, 0.97g/L Mn²⁺ and 0.5g/L Cr³⁺ as feed in mixer-settlers showed that the process had run stably with 98% recovery of nickel. The concentration of nickel in strip liquors reached as high as 50 g/L while the removals of Fe³⁺, Fe²⁺, Mg²⁺, Al³⁺, Ca²⁺, Mn²⁺ and Cr³⁺ were 98.5%, 91.5%, 99.95%, 99.8%, 99.1%, 98.6% and 99.5%, respectively. The industrial test with the sulfuric acid leach solution of electroplating sludge containing 11.5g/L Ni²⁺, 2.68g/L Fe³⁺, 7.54g/L Cr³⁺, 0.61g/L Mg²⁺, 2.09g/L Al³⁺, 0.68g/L Ca²⁺, 0.022g/L Mn²⁺ and 0.154g/L SiO₂ as feed in mixer-settlers also showed that the process had operated successfully with 99.5% recovery of nickel. The concentration of nickel in strip liquors reached 42.7 g/L while the removals of Fe³⁺, Cr³⁺, Mg²⁺, Al³⁺, Ca²⁺, Mn²⁺ and SiO₂ were 99.2%, 99.77%, 99.73%, 99.56%, 99.57%, 98.51% and 98.75%, respectively. The new process exhibited big advantages of short flow sheet, high recovery of nickel, high removal of impurities, low chemical reagent consumption and low cost. Application of this process in industry is expected to make important impact on the extraction of nickel from sulfuric acid leach solutions and to deliver good environmental and economical benefits.