Influence of humic acids in solution on uranium solvent extraction

The harmful influence of humic acids in solution on uranium solvent extraction is investigated in this paper. The influence appears to be the poor phase separation and forming stable emulsion when uranium is extracted or stripped, and decreasing the loaded uranium in organic phase. The extractions of organic matter and solvent extraction of uranium were carried out for three sedimentary uranium ores. The results show that the stable emulsions of w/o or o/w type are formed separately with organic solvent containing tertiary amine or D2EHPA when uranium from liquors containing humic acid is extracted. Several humic acids of different molecular weight were fractionated by means of fractional solution containing varicus volume ratio of ethanol-ethylacetate. The physical characters and chemical composition of the humic acids were determined. It is found that there is distinct difference in emulsion-causing character among the humic acids with different molecular weight. The removal methods of humic acid from aqueous and organic solutions are discussed briefly