Abstract:
A new method of separation and recovery of Pt(CN)
42− from alkaline cyanide solution media was investigated using Aliquat-336 as extractant. The effects of modifier content, the metal ions concentration, solution pH, equilibrium time, phase ratio, and the Aliquat-336 concentration were investigated in details. Almost all Pt(CN)
42−, Fe(CN)
63−, and Co(CN)
63− (>99.0%) could be simultaneously extracted by Aliquat-336 under optimum conditions. Furthermore, Pt(CN)
42− was recovered by the two-step stripping process. First, Fe(CN)
63− and Co(CN)
63− in the loaded Aliquat-336 were stripped by a 0.7 mol·L
−1 KCl solution. The stripping percentages for both Fe(CN)
63− and Co(CN)
63− were above 95.0 %, whereas the stripped Pt(CN)
42− was below 5.0%. Second, more than 94.0% Pt(CN)
42− in the loaded Aliquat-336 could be stripped using 2.0 mol·L
−1 KI solution. The organic phase could be reused for at least 4 cycles of extraction-stripping processes. The recovery ratio for Pt(CN)
42− was above 92.0% after four testing cycles. According to the infrared spectrum, ultraviolet spectrum,
1H NMR, continuous transformation method, and Karl Fischer titration method, the extraction reactions were deduced to be ion exchange mechanisms.