REMOVAL OF NITRIC ACID FROM CONCENTRATED PHOSPHORIC ACID BY EXTRACTION WITH METHYL ISOBUTYL KETONE IN AROMATIC DILUENTS

The extraction of nitric acid from concentrated phosphoric acid solutions by methyl isobutyl ketone (MIBK) dissolved in aromatic diluent has been studied. Nitric acid can be effectively removed by MIBK from the solutions containing 50–75% H₃P0₄. With increasing the concentration of either H₃PO₄ or MIBK, the distribution coefficient of HN0₃ increases but the separation factor for HN0₃ against H₃PO₄ decreases. However, it is possible to achieve a complete removal of HN0₃ in a few of stages and the coextraction of H₃PO₄ can be limited to less than 1%.     

THE EXTRACTION OF COBALT(II) FROM A THIOCYANATE MEDIUM BY SOME DIAMINE AND MONOAMINE EXTRACTANTS DISSOLVED IN 5% ISODECANOL - BENZENE

The tertiary amine extractants N,N,N’,N’-tetra-n-octylethylenediamine, N,N-di-n-octyl-2-(aminomethyl)pyridine and Alamine 336 were used to extract cobalt(II) from a thiocyanate medium. The extraction equilibria were identified and the extraction constants for these equilibria are presented.

Thiocyanic and sulphuric acid extraction was investigated. The protonation constants of the tertiary amines with these acids are reported.

The potential of the chelate mode, displayed by tertiary diamine extractants, was evaluated. The extraction properties of tertiary diamine extractants were demonstrated to be superior to a tertiary monoamine extractant, Alamine 336.     

EXTRACTION OF AMERICIUM(III) FROM CHLORIDE MEDIA BY OCTYL(PHENYL)-N,N-DIISOBUTYLCARBAMOYLMETHYLPHOSPHINE OXIDE∗

The extraction of Am(III) from chloride media was studied using octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide, Oπ D(iB)CMPO or CMPO, dissolved in tetrachloroethylene. Although the extraction of Am(III) by 0πD(iB)CMPO is many orders of magnitude weaker from chloride than nitrate media, the rapid Increase in the mean activity of chloride in HC1 and in most soluble chloride salts with concentration makes extraction from moderate to concentrated hydrochloric acid and/or concentrated Li, Mg, Ca, and Al chloride salt solutions practical. The stoichiometry of the extractable chloro complex was established by extractant dependency and loading experiments and found to be AmCl₃»3CMPO. Hydrochloric acid appears to be associated with the complex when extraction takes place at high HC1 concentrations. The mode of coordination of OπD(iB)CMPO to AmCl₃appears to be bidentate in marked constrast to its behavior in the corresponding nitrate system.     

Para‐substituted 1‐Phenyl‐3‐methyl‐4‐aroyl‐5‐pyrazolones as Selective Extractants for Vanadium(V) from Acidic Chloride Solutions

Abstract

Para‐substituted 4‐aroyl derivatives of 1‐phenyl‐3‐methyl‐5‐pyrazolones (HX), namely, 1‐phenyl‐3‐methyl‐4‐(4‐fluorobenzoyl)‐5‐pyrazolone (HPMFBP) and 1‐phenyl‐3‐methyl‐4‐(4‐toluoyl)‐5‐pyrazolone (HPMTP) were synthesized and examined with regard to the extraction behavior of multivalent metal ions such as magnesium(II), aluminum(III), titanium(IV), vanadium(V), chromium(III), manganese(II), iron(II), and iron(III) that are present in titania waste chloride liquors. For comparison, studies have also been carried out with 1‐phenyl‐3‐methyl‐4‐benzoyl‐5‐pyrazolone (HPMBP). The results demonstrate that vanadium(V) and iron(III) are extracted into chloroform with 4‐aroyl‐5‐pyrazolones as VO₂X · HX and FeX₃, respectively. On the other hand, magnesium(II), aluminum(III), titanium(IV), chromium(III), manganese(II), and iron(II) were not found to be extracted into the organic phase. The equilibrium constants of vanadium(V) and iron(III) with various 4‐aroyl‐5‐pyrazolones follow the order HPMFBP>HPMBP>HPMTP, which is in accordance with their pKa values. The selectivity between vanadium(V) and iron(III) increases with increasing hydrochloric acid concentration. Further, it is clear from the results that iron(III) is not getting extracted above 1.0 mol dm^?3 hydrochloric acid solution. The electronic and IR spectra of the extracted complexes of vanadium(V) and iron(III) were used to further clarify the nature of the extracted complexes. The potential of these reagents for the selective extraction and separation of vanadium(V) from titania waste chloride liquors has also been discussed.     

Temperature-Swing Gas Separation with Electrothermal Desorption Step

Abstract

Results of an experimental investigation of a new method for heating adsorbent beds in the desorption step owing to Joule's heat generated inside the adsorbent particles by passing an electric current through them are presented. Desorption of a previously saturated bed and cyclic separation with the electric potential applied to a fibrous activated carbon bed was performed.     

Solvent Extraction of Indium,Gallium, and Zinc Ions with Acidic Organophosphates having Bulky Alkyl Groups

The extraction equilibria of In³⁺, Ga³, and Zn²⁺ with bis(4‐ethylcyclohexyl)phosphoric acid (D4ECHPA), bis(4‐cyclohexylcyclohexyl)phosphoric acid (D4DCHPA), and bis(2‐ethylhexyl)phosphoric acid (D2EHPA) were investigated in acidic aqueous sulfate media. The order of extractability of metal ions is D4DCHPA > D2EHPA > D4ECHPA, which corresponds to the lipophilicity (log P) of the extractants. The separation factors, β_(In/Ga) and β_(Ga/Zn), of D4ECHPA and D4DCHPA are greater or comparable than that of D2EHPA, because of the steric hindrance of the bulky cyclohexyl groups. In³⁺ can be therefore separated from simulated liquor containing a high concentration of Zn²⁺ by D4DCHPA.     

单参数Wilson方程预测C_9-DMP体系汽液平衡

根据实测γ~∞_1用单参数Wilson方程预测均三甲苯-DMP和偏三甲苯-DMP二元体系汽液平衡,并推算均三甲苯-偏三甲苯-DMP三元体系的汽液平衡,与实测数据比较,均获得良好结果。     

Synergistic extraction of rare earths(III) from chloride medium with mixtures of 1‐phenyl‐3‐methyl‐4‐benzoyl‐pyrazalone‐5 and di‐(2‐ethylhexyl)‐2‐ethylhexylphosphonate

The synergistic effect of 1‐phenyl‐3‐methyl‐4‐benzoyl‐pyrazalone‐5 (HPMBP, HA) and di‐(2‐ethylhexyl)‐2‐ethylhexylphosphonate (DEHEHP, B) in the extraction of rare earths (RE) from chloride solutions has been investigated. Under the experimental conditions used, there was no detectable extraction when DEHEHP was used as a single extractant while the amount of RE(III) extracted by HPMBP alone was also low. But mixtures of the two extractants at a certain ratio had very high extractability for all the RE(III). For example, the synergistic enhancement coefficient was calculated to be 9.35 for Y³⁺, and taking Yb³⁺ and Y³⁺ as examples, RE³⁺ is extracted as RE(OH)A₂.B. The stoichiometry, extraction constants and thermodynamic functions such as Gibbs free energy change ΔG (?17.06 kJ mol^?1), enthalpy change ΔH (?35.08 kJ mol^?1) and entropy change ΔS (?60.47 J K^?1 mol^?1) for Y³⁺ at 298 K were determined. The separation factors (SF) for adjacent pairs of rare earths were calculated. Studies show that the binary extraction system not only enhances the extraction efficiency of RE(III) but also improves the selectivity, especially between La(III) and the other rare earth elements. Copyright © 2006 Society of Chemical Industry