Organophosphorus acids solvent extractions

Preston, J. S. duPreez, A. C. Solvent extraction of nickel from acidic solutions using synergistic mixtures containing pyridinecarboxylate esters. 1. Systems based on organophosphorus acids. J. Chem. Technol. Biotechnol. 1996, 66, 86-94. 

Preston, J. S. Solvent extraction of cobalt and nickel by organophosphorus acids. I. Comparison of phosphoric, phosphonic, and phosphinic acid systems. Hydrometallurgy 1982, 9, 115-133. 

Solvent extraction of base metals by organophosphorus acids 792... 

In the Nippon Mining Company process,163 the aqueous feed consists of a solution of cobalt, nickel and other metal sulfates obtained by the high-pressure oxidative leaching of a mixed metal sulfide ore. Following the removal of iron and copper by chemical precipitation methods, and the successive extraction of zinc and cobalt by organophosphorus acid reagents (Section 63.3.2.2) under weakly acidic conditions, the pH value of the solution is adjusted to between 9 and 9.5 with ammonia, and nickel is extracted into a 25% solution of LIX 64N in an alkane solvent. 

Modolo, G., Odoj, R. 1999. Synergistic selective extraction of actinides(IH) over lanthanides from nitric acid using new aromatic diorganyldithiophosphinic acids and neutral organophosphorus compounds. Solvent Extr. Ion Exch. 17 (1) 33-53. 

Blake, C.A. Jr. Baes, C.F. Jr. Brown, K.B. Coleman, C.F. White, J.C. Solvent extraction of uranium and other metals by acidic and neutral organophosphorus compounds, In Peaceful Uses of Atomic Energy. Vol. 28, Basic Chemistry in Nuclear Energy, United Nations, Geneva (1958), pp. 289-298. 

Solvent Extraction of Transplutonium Elements from Acid Solutions by Polydentate Neutral Organophosphorus Compounds and from Alkaline Solutions by Quarternary Ammonium Bases and by Alkylpyrocatechols... 

Experimental studies were therefore directed to investigate the removal of actinides from both diluted (5000 l/t) and concentrated (about 500 l/t) HAW solutions. Three alternative processes have been selected for this purpose. They all rely upon actinide separation at low acidity conditions requiring a preliminary denitration step. Two of them (TBP and HDEHP processes) are based on solvent extraction techniques using as extractants a neutral (TBP) and an acidic (HDEHP) organophosphorus compound respectively. The third process (OXAL) applies as the first step the precipitation of actinides and lanthanides FP as oxalates. 

Neuman RD, Nai-Fu-Zhou WuJ, Jons MA, Gaonkar AG, General model for aggregation of metal-extractant complexes in acidic organophosphorus solvent extraction systems. Sep. Sci. Technol. 1990 25(13-15), 1655-1674. 

The state of the art of nickel and cobalt solvent extraction in the nickel laterite industry is assessed, covering the reagents in commercial use (organophosphorus reagents, carboxylic acids, chelating oximes and amines), research developments and chemical fundamentals that result in the different approach taken with each of the reagent types. 

---