Process for the extraction of gallium

A process for the extraction of gallium from a basic aqueous solution containing gallium comprising the steps of:

• (a) contacting an aqueous solution containing gallium with a solution in a water immiscible solvent of at least one compound of the formula (A), ##STR8## wherein:
• Q is a hydrogen atom, a hydrocarbyl group or a group --CH.sub.2 Z;
• Z is a --COOH group or a 2-hydroxyphenyl group which may optionally be substituted by the groups R.sub.12, R.sub.13 and R.sub.14 ;
• R.sub.1 to R.sub.9, and R.sub.12 and R.sub.14, which may be the same or different, are substituent groups selected from hydrogen, hydrocarbyl, alkoxy, halogen, hydrocarbyl, sulphonyl, acyl, amino, nitro and cyano or, when R.sub.1 and R.sub.2 and/or R.sub.4 and R.sub.5 are adjacent substituents they may complete a benzo ring and R.sub.1 to R.sub.9 and R.sub.12 to R.sub.14 are such that the substituents on at least one of the rings are different from the substituents on at least one other of the rings;
• R.sub.10 And R.sub.11 are each, independently, a hydrogen atom or an alkyl group containing up to 20 carbon atoms;
• Y.sub.1 is a hydrogen atom, or an alkyl group containing up to 20 carbon atoms, or a phenyl group;
• Y.sub.2 is a hydrogen atom or an alkyl group containing up to 20 carbon atoms, or Y.sub.1 and Y.sub.2, together with the group ##STR9## to form saturated or unsaturated ring system;
• and R.sub.1 to R.sub.14, Y.sub.1 and Y.sub.2 are the same or different and together contain in total from 10 to 60 saturated carbon atoms,
• (b) separating the aqueous phase from the solvent phase which contains a gallium complex compound;
• (c) contacting the solvent phase with an aqueous mineral acid or with an aqueous solution which is more strongly alkaline than the aqueous solution of steps (a) and (b);
• and
• (d) separating the solvent phase from the aqueous phase containing metal in the form of a salt of the mineral acid or of an oxyanion.