Extraction of Gold from Alkaline Gold Leaching Solution by Tertiary Amine N235 and Phosphine Oxide
Extraction of gold from alkaline gold leaching solution by N235-TRPO synergistic system was studied. The effects of the concentrations of Tri-akylphosphine oxide(TRPO)and tertiary amine(N235), the initial pH, and the concentration of gold on the extraction of gold and the extraction isotherm were inspected. The ability of extracting other metal elements by this system had been investigated. The effect of alkali concentration on stripping of gold from loaded organic phase had also been studied. The experimental results indicate that the system consisting of 10% N235, 10% TRPO gave high extraction yield for gold along with the lesser extraction of silver and copper which are needed to recover. The gold extraction was over 94%, at pH=9~10 and the stripping of gold from loaded organic phase using 0.05mol/L NaOH can reach91.43%.
Synergism in gold–cyanide extraction with Primene JMT–Cyanex 925 mixed extractant system
Abstract The synergic extraction of gold (I) from cyanide solutions has been studied using a mixture of Primene JMT (primary amine=RNH 2 ) and Cyanex 925 (bis(2,4,4,trimethylpentylactyPhosphine oxide=R 3 PO) in xylene. The variables that could affect the extraction system were investigated: equilibration time, temperature, aqueous pH, extractant mixture concentration, metal concentration and organic phase diluent. The selectivity of the system with respect to the extraction of different metal–cyano complexes was also evaluated. The gold (I) extraction reaction is discussed on the basis of the experimental results and numerical treatment of the experimental data. The species formed in the organic phase have the probable stoichiometry H + Au(CN) 2 − RNH 2 (R 3 PO) n , n being 1 (log K ext =10.27 max 10.55) or 3 (log K ext =12.80±0.13). Stripping of gold from loaded organic solutions was also studied using low ionic strength alkaline solutions at different experimental conditions.
The application of primene 81R for the purification of concentrated aluminium sulphate solutions from leaching of clay minerals
Abstract A method of separating iron(III) and aluminium by solvent extraction treatment of sulphate leach liquors produced by the acid leaching of domestic non-bauxitic ores is reported. The principal impurity to be eliminated was iron(III). The amine Primene 81R was investigated for both synthetic solutions and leach liquors. The effect of aluminium, sulphuric acid, amine concentrations and other variables upon extraction was studied. The use of sulphuric acid and basic solutions as stripping agents was also studied. Extraction and stripping isotherms were used as a basis for laboratory-scale tests in single-stage and multi-stage studies. The iron concentration in the aqueous solution can be decreased from 2 kg/m3 to 0.015 kg/m3.