Recovery of the components of group III-V material aqueous wastes

A method for the separation of gallium from an aqueous waste containing gallium arsenide comprising the following steps in the order indicated:

• adjusting the pH of an aqueous waste containing gallium arsenide to a pH from about 9.5 to about 12.5 by adding an alkali metal hydroxide base;
• precipitating an alkaline metal arsenate by adding an alkaline metal salt to said aqueous waste;
• separating said alkaline metal arsenate from said aqueous waste;
• adjusting the pH of said aqueous waste to form a gallium hydroxide precipitate by adding a mineral acid to said aqueous waste;
• separating said gallium hydroxide precipitate from said aqueous waste;
• and
• recovering gallium from said gallium hydroxide precipitate.

A method for the separation of a group III element from an aqueous waste containing a group III element phosphide comprising the following steps in the order indicated:

• adjusting the pH of an aqueous waste containing a group III element phosphide to a pH from about 9.5 to about 12.5 by adding an alkali metal hydroxide base;
• precipitating an alkaline metal phosphate by adding an alkaline metal salt to said aqueous waste;
• separating said alkaline metal phosphate from said aqueous waste;
• adjusting the pH of said aqueous waste to form a group III element hydroxide precipitate by adding a mineral acid to said aqueous waste;
• separating said group III element hydroxide precipitate from said aqueous waste;
• and
• recovering a group III element from said group III metal hydroxide precipitate.