Experimental design modelling for the extraction of vanadium(IV) extraction V(IV)-SO4 2- (H+, Na+)-Cyanex 301-kerosene system

The vanadium(IV) extraction from acidic sulphate medium by Cyanex 301 (bis-(2,4,4-trimethylpentyl) dithiophosphinic acid) dissolved in kerosene is explored from the modelling point of view. The time of equilibration is only 10 min and above pH(eq) = 2, high extraction (>90%) occurs.On keeping organic to aqueous phase ratio of 1, factors affecting the extent of extraction (log D and log CD) are pH(eq), [V(IV)],[SO4 2-], [Cyanex 301]and temperature (T). The high (+) and low (-) levels are considered for the factors. The 25 factorial design is used to find the regression equation for the V(IV) extraction by Cyanex 301. On symbolizing pH(eq), log [V(IV)], , log [SO4 2-], log [Cyanex 301], and 1/T (K-1); where concentration terms are in mol/L, as P , M, S,E, and (1/T), respectively,the regression equation obtained is: log CD = 1.95 - 0.23 M + 1.83 P + 2.07 E + 0.84 S - (888.9/T) - 0.26 PS.The current system shows only the interaction effect among pH(eq) and [SO4 2-]. The equation can well describe the system,and it can be used to optimize factors for satisfactory extraction. Bangladesh J. Sci. Ind. Res.56(2), 95-104, 2021

Application of Plasticized Cellulose Triacetate Membranes for Recovery and Separation of Cerium(III) and Lanthanum(III)

This work explains the application of plasticized cellulose triacetate (CTA) membranes with Cyanex 272 di(2,4,4-(trimethylpentyl)phosphinic acid) and Cyanex 301 (di(2,4,4-trimethylpentyl)dithiophosphinic acid) as the ion carriers of lanthanum(III) and cerium(III). CTA is used as a support for the preparation of polymer inclusion membrane (PIM). This membrane separates the aqueous source phase containing metal ions and the receiving phase. 1M H2SO4 is applied as the receiving phase in this process. The separation properties of the plasticized membranes with Cyanex 272 and Cyanex 301 are compared. The results show that the transport of cerium(III) through PIM with Cyanex 272 is more efficient and selective than lanthanum(III).

Germanium Extraction from Sulfuric Acid Solutions in the Presence of Thiocyanate Ion

The extraction of Ge (IV) from sulfuric acid solutions in the presence of thiocyanate ion with various extractants (caprylic, poly(2-ethylhexyl)phosphonitrile, bis(2,4,4-trimethylpentyl) dithiophosphinic acids, trialkylmethylammonium thiocyanate, etc.) has been studied. In all cases, the thiocyanate ion increases germanium extraction as compared to the extraction from sulfuric acid solutions. During the germanium extraction with bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301, HR), a significant increase in the germanium extraction is due to the formation of a cationic intracomplex compound of the composition [Ge(OH)3-nRn]+[HSO4], where n = 1-3. Due to the large synergistic effect for the extraction of Ge, it is possible to use an extractant with a concentration of 0.1-0.15 mol/l. Trialkylmethylammonium thiocyanate (TAMAR), also shows a high efficiency of germanium extraction from sulfate thiocyanate solutions. For 5-6 stages of extraction with a 0.5 M solution of ТАМАР, the extraction of Ge was 99.5 %. The composition of the extracted complex supposedly corresponds to (R4N)2[Ge(CNS)6]. The use of extraction systems based on Cyanex 301 and ТАМАR in the presence of thiocyanate ion significantly reduces the concentration of extractants and is of undoubted practical interest for hydrometallurgical processes for the germanium extraction

Review on the Comparison of the Chemical Reactivity of Cyanex 272, Cyanex 301 and Cyanex 302 for Their Application to Metal Separation from Acid Media

Cyanex extractants, such as Cyanex 272, Cyanex 301, and Cyanex 302 have been commercialized and widely used in the extraction and separation of metal ions in hydrometallurgy. Since Cyanex 301 and Cyanex 302 are the derivatives of Cyanex 272, these extractants have similar functional groups. In order to understand the different extraction behaviors of these extractants, an understanding of the relationship between their structure and reactivity is important. We reviewed the physicochemical properties of these extractants, such as their solubility in water, polymerization degree, acidity strength, extraction performance of metal ions, and the interaction with diluent and other extractants on the basis of their chemical structure. Synthetic methods for these extractants were also introduced. This information is of great value in the synthesis of new kinds of extractants for the extraction of metals from a diverse medium. From the literature, the extraction and stripping characteristics of metals by Cyanex 272 and its derivatives from inorganic acids such as HCl, H2SO4, and HNO3 were also reviewed. The replacement of oxygen with sulfur in the functional groups (P = O to P = S group) has two opposing effects. One is to enhance their acidity and extractability due to an increase in the stability of metal complexes, and the other is to make the stripping of metals from the loaded Cyanex 301 difficult.

Study of the Stability of Cyanex 301 and its Salts in the Presence of Oxidizing Agents

The effect of oxidizing agents on the stability of bis (2,4,4-trimethylpentyl) dithiophosphinic acid (НR, Cyanex 301) and its extracts with Cu, Ni, Co, and Zn in decane and toluene was studied. It was shown that the stability of НR and extracts varies in the following series of oxidizing agents: HNO3> H2O2> J2. In a mixture of Cyanex 301 with trioctylamine, the oxidation of the extractant is much more effective than with Cyanex 301 alone. The degree of degradation of Cyanex 301 is higher than that of extracts, which indicates a higher stability of НR salts in comparison with the acid itself. The main oxidation products of Cyanex 301 and its extracts (NiR2 and ZnR2) with HNO3, H2O2 and J2 were determined