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Separation and recovery of Pd( II ) and Pt( II ) from cyanide liquors of Pd‐Pt flotation concentrate via solvent extraction
Author(s) -
Chen Muhan,
Wu Shengjie,
Huang Zhangjie,
Chen Jing,
Chen Min Jun
Publication year - 2017
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.5168
Subject(s) - chemistry , cyanide , palladium , platinum , ammonium thiocyanate , extraction (chemistry) , thiocyanate , stripping (fiber) , bromide , leaching (pedology) , ammonium bromide , nuclear chemistry , solvent extraction , inorganic chemistry , chromatography , catalysis , organic chemistry , materials science , environmental science , pulmonary surfactant , biochemistry , soil science , soil water , composite material
BACKGROUND Thus far, separation and recovery of Pd( CN ) 4 2‐ and Pt( CN ) 4 2‐ from cyanide liquors have not been reported. In this study, the process of co‐extracting and separating Pd( II ) and Pt( II ) over Fe( III ), Cu(I), Co( III ), and Ni(I) from alkaline cyanide liquors was investigated. RESULTS The results showed that almost all Pd( II ) and Pt( II ) (>98.0%) could be simultaneously extracted by phenoxyethyl dimethyl palmitylammonium bromide ( PDPB ), whereas Fe( III ), Cu(I), Co( III ), and Ni(I) was below 3.0% under optimum conditions. Furthermore, Pd( CN ) 4 2‐ and Pt( CN ) 4 2‐ were separated and recovered by the two‐step stripping process. First, Pd( CN ) 4 2‐ in mixed organic phase was stripped by a 2.0 mol L −1 ammonium thiocyanate solution. The stripping percentage of Pd( CN ) 4 2‐ was >98%, whereas the stripped Pt( CN ) 4 2‐ was below 1%. Second, more than 97.5% Pt( CN ) 4 2‐ in the loaded organic phase could be stripped using 1.0 mol L −1 thiodiglycol solution. Recovery ratios for both Pd( II ) and Pt( II ) were above 95%. The organic phase could be reused for at least 6 cycles of extraction–stripping processes. The mechanisms of extraction reaction were deduced to be ion‐association mechanisms. CONCLUSION The process could be applied for extracting and separating palladium and platinum from the cyanide leaching liquor of the flotation concentrate. © 2016 Society of Chemical Industry