Separation of platinum and rhodium from chloride solutions containing aluminum, magnesium and iron using solvent extraction and precipitation methods.
The solvent extraction and precipitation methods have been used to develop a process to separate platinum and rhodium from a synthetic chloride solutions containing other associated metals such as (mg/L): Pt-364, Rh-62, Al-13880, Mg-6980, Fe-1308 at <1M HCl acidity. At pH 3.4, the quantitative precipitation of Al and Fe was achieved using 10 wt% Na(3)PO(4)·12H(2)O, with ~4% loss of Pt and Rh due to adsorption phenomenon. The selective separation of platinum was carried out with 0.01 M Aliquat 336 (a quaternary ammonium salt) at an aqueous to organic ratio (A/O) of 3.3 in two stages. Stripping of Pt from loaded organic (LO) at O/A ratio 6 with 0.5 M thiourea (tu) and HCl indicated that ~99.9% stripping efficiency. In stripping studies, needle like crystals of Pt were found and identified as tetrakis (thiourea) platinum (II) chloride ([Pt(tu)(4)]Cl(2)). The selective precipitation of rhodium was performed with (NH(4))(2)S from platinum free raffinate with a recovery of >99%.
Inorganic Chemistry Division, Indian Institute of Chemical Technology (CSIR), Hyderabad, Andhra Pradesh, India.
B
B
Raju
J Rajesh
JR
Kumar
Jin-Young
JY
Lee
Hyuk-Sung
HS
Kwonc
M Lakshmi
ML
Kantam
B Ramachandra
BR
Reddy
D011232:Chemical Precipitation; D002712:Chlorides / Q000737:chemistry*; D008670:Metals / Q000737:chemistry* / Q000302:isolation & purification; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D059027:Recycling / Q000379:methods; D012996:Solutions; D012997:Solvents / Q000737:chemistry
D002712:Chlorides; D008670:Metals; D000644:Quaternary Ammonium Compounds; D012996:Solutions; D012997:Solvents; C037759:trioctylmethylammonium