Solvent extraction process for the selective recovery of copper and cobalt from carrollite leach solution

A solvent extraction application consisting of three-sequential solvent extraction steps to selectively recover the copper and cobalt from carrollite leach solution was conceived and experimentally explored. The first step allowed the simultaneous extraction of 95.5% copper, 0.87% cobalt and 4.79% iron using 20% Lix984 in sulfonated kerosene and O/A ratio of 1 at initial pH of 2. Two-stage scrubbing at pH = 4 using diluted sulphuric acid solution allowed the removal of most of the cobalt (98.56%), iron (97.25%) and small amount of copper (0.36%). Complete stripping of copper was achieved at H2SO4 concentration of 1.5 mol/L and an O:A ratio of 1. This raffinate was the feed for the second step. The use 30% P204 in sulfonated kerosene, sodium-saponification rate of 30% and initial pH of 2.5 allowed the removal of 100% iron, 98.45% zinc, 93.64% calcium and 22.77% magnesium under the O:A ratio of 1 but with substantial co-removal of cobalt (8.23%). Two-stage scrubbing of this loaded organic phase at pH = 2.5 using diluted sulphuric acid solution allowed the extraction of most of the cobalt (92.75%). This raffinate was the feed for the third step. The simultaneous extraction of 99.08% cobalt, 5.12% magnesium and 2.87% nickel was found using 35% P507 in sulfonated kerosene, sodium-saponification rate of 65% and initial pH of 4 at an O:A ratio of 1:2. Two-stage scrubbing at pH = 3.5 using diluted sulphuric acid solution allowed the removal of most of the magnesium (96.82%), nickel (93.49%) and small amount of cobalt (2.87%). Complete stripping of cobalt was achieved at H2SO4 concentration of 1.0 mol/L at an O:A ratio of 3:1. Meanwhile, as long as the phase ratio (O/A) of extraction and stripping were properly controlled, this diluted cobalt solution can be concentrated before being sent to a subsequent step such as recovery of the metal by electrowinning. Based on the experimental results, a flowsheet for the extraction process is presented.

Effect of structure on extraction behavior of praseodymium with a series of unsymmetrical diglycolamides from hydrochloric acid

The extraction behavior of Pr(III) has been investigated using four kinds of unsymmetrical diglycolamide (DGA) extractants having different alkyl chain lengths, namely N,N?-dimethyl-N,N?-didodecyldiglycolamide (DMDDdDGA), N,N?-diethyl-N,N?-didodecyldiglycolamide (DEDDdDGA), N,N?-dipropyl-N,N?-didodecyldiglycolamide (DPDDdDGA) and N,N?-dibutyl- N,N?-didodecyldiglycolamide (DBDDdDGA). The effect of the alkyl chain of amidic N atoms in DGAs on the extraction ability of Pr(III) is discussed. The extraction of hydrochloric acid and Pr(III) from hydrochloric acid medium by DGAs in sulfonated kerosene, toluene and octanol was studied. The effect of extractant concentration and diluents on the distribution ratio (D) of Pr(III) was investigated to understand the extraction mechanism. Pr(III) and Fe(III) can be separated very well by DMDDdDGA and DBDDdDGA diluted by toluene in hydrochloric acid solution. IR spectra of extracted species of DGA?HCl and DGA?Pr(III) were recorded to study the structure of the extracted species.

Research on Separating Rubidium from Deep Potassium-Rich Old Brine by Solvent Extraction

A deep potassium-rich old brine in Hubei Province contains a large number of rubidium resource. Separation of rubidium is very difficult due to the similar physical and chemical properties of rubidium with the other coexisting alkali metals (potassium, sodium, and lithium). The process of extracting and separating Rb from the old brine with 4-tert-butyl-2-(α-methylbenzyl) phenol(t-BAMBP) as the extraction agent and sulfonated kerosene as diluents was systematically studied in this paper. The concentration of extraction agent, alkalinity of the old brine, phase ratio, the extracting time and other related factors were investigated. The optimal extraction conditions were obtained as follows: the concentration of t-BAMBP was 1.0mol/L, the concentration OH- was 0.6mol/L, the phase ratio was 3, the extraction time was 3 minutes. The percentage extraction of Rb could reach 91% for single-stage extraction, the separation coefficient of Rb and K reached up to 16.15. Sulfonated kerosene as diluent is non-toxic, high flash point, non-environmental pollution. A high extraction rate and separation factor for the development of rubidium resource of deep potassium-rich brine provided a reliable basis.

Extraction of Scandium from Red Mud Using ELM with P204 as Carrier

Scandium is an important rare earth element. Stacking of red mud has caused serious environmental and social issues. Red mud is rich in scandium. In this paper, recovery of scandium from red mud by emulsion liquid membrane (ELM) was studied. Composition of ELM is P204-Span80-sulfonated kerosene-HCl. Effects of mobile carrier and surfactant concentration, Roi, Rwe, internal and external aqueous phase acidity on the extracting rate of Sc3+ were studied. Results show that it is feasible for P204-Span80-Sulfonated Kerosene-HCl ELM System extracting Sc3+ from red mud leaching solution. The optimum condition is P204=12%, Span80=3%, Roi= 2:3, Rwe=6, the internal aqueous c(HCl)= 4mol/L, the external aqueous phase pH=2, the time of making emulsion is 20 minutes, extracting time is 15 minutes. The extracting rate of Sc3+ can reach to 99.6% under optimal condition. The extracting rate of other impurities is lower than 5%.