STUDY OF LI+ ADSORPTION ONTO POLYMERIC ALUMINUM(III) HYDROXIDE FOR APPLICATION IN THE TREATMENT OF GEOTHERMAL WATERS

Li+ adsorption onto aluminium hydroxide has been investigated at vario us temperatures. Experiments were made on two high-salinity geothermal -type fluids in which the lithium concentration reaches values greater than 30 and 50 mmol(-1) respectively, in order to study the recovery of lithium from the fluids. Aluminium hydroxide was produced by adding AlCl3 . 6H(2)O salt and KOH solution to the two reconstituted fluids. Experiments were performed at various pH values, temperatures (20, 50 and 80 degrees C) and Al contents. The results indicate high Li+ adso rption rates for both fluids at 80 degrees C, even under conditions wh ere small amounts of Al salt were added to the fluids. Under certain c onditions, the chemical composition of the geothermal fluids had an in fluence on the Li+ adsorption rate. The presence of certain ions in so lution, such as berate, which prevent Li+ adsorption, is therefore dis cussed. Experiments on the desorption of lithium from aluminium hydrox ide using dilute solutions of hydrofluoric and sulphuric acid gave goo d results for the hydrofluoric acid.