Solvent extraction of scandium from pregnant leach solution of nickel laterites


Thesis Type: Post Graduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Metallurgical and Materials Engineering, Turkey

Approval Date: 2017

Student: ECE FERİZOĞLU

Co-Consultant: YAVUZ ALİ TOPKAYA, RIZA GÜRBÜZ

Abstract:

The aim of this thesis study is the extraction and recovery of scandium from lateritic nickel-cobalt ores by using the solvent extraction method. In this study, different organic and scrubbing reagents were investigated in order to find the most suitable organic extractant for the extraction of scandium with low impurity co-extraction and scrubbing reagent to remove the extracted impurities from the loaded organic phase. In the first part, different organic reagents that are DEHPA, Cyanex 272, Cyanex 923, Ionquest 801 and Primene JMT, were investigated. After the determination of the most suitable organic extractant, synergetic systems were examined and for this reason, TBP and isodecanol, which are defined as modifiers in solvent extraction systems, were used with the previously determined organic extractant. In addition to these, the effects of kerosene type, the pH of the aqueous solution and the volume ratio of organic to aqueous phase on extraction were investigated. Therefore, it was determined that 5% DEHPA + 1% TBP + 94% D80 with A/O: 10/1 phase ratio at pH=0.8 for 10 minutes mixing duration were suitable conditions for scandium extraction. After the extraction, the suitable scrubbing reagents were investigated for the loaded organic. In this part, iron and aluminum are the most critical impurities as well as nickel and cobalt and the main aim is to remove particularly these impurities from the loaded organic phase. In consideration of this, oxalic acid, HCl and H2SO4 were used in the experiments with different molarities. As a result of the series of experiments, 0.75M oxalic acid at O/A: 3/1 phase ratio was determined as a suitable condition for scrubbing.