Extraction of titanium (IV) from acidic media by 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester

摘要

The extraction of titanium(IV) from sulphate, chloride and nitrate solutions has been investigated using 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (EHEHPA) in kerosene. The kinetics of extraction was slow, requiring 60 min for the complete extraction of titanium and was improved with the increase of the extractant concentration in the organic phase. When the acid concentration in the aqueous feed phase was varied from 0.5 M to 4 M, the distribution ratios of titanium showed minimal values at 1-2 M acid. The effect of the initial concentration of titanium on extraction was found to be negligible, indicating the presence of mononuclear species in the aqueous phase. The stripping of titanium was studied using H_2SO_4, H_2SO_4+H_2O_2 and Na_2CO_3. The kinetics of the stripping was very slow when sulphuric acid was used, but was improved with complex forming shipping agents (H_2SO_4+H_2O_2 and Na_2CO_3). The extraction and stripping of titanium were 100 percent using an aqueous nitrate medium and sodium carbonate strip. Hence, results generated would be applicable to separate titanium from secondary sources such as fly ash originated from incinerators of Municipal Solid Waste.