Process for preparing an adsorbing material comprising a precipitating step of boehmite according to specific conditions and process for extracting lithium from saline solutions using this material

A method for preparing a crystallized solid material of formula LiXx.2Al(OH)3,nH2O with n being comprised between 0.01 and 10, x being equal to 1 when X is an anion selected from among chloride, hydroxide and nitrate anions, and x being equal to 0.5 when X is an anion selected from among sulfate and carbonate anions, said method comprising:

• a) precipitating boehmite in an aqueous medium, wherein the precipitation comprises contacting at least one basic precursor;
• and at least one acid precursor, wherein at least one of the basic or acid precursors comprises aluminium, thereby obtaining a suspension of boehmite, said precipitating being performed at a temperature comprised between 5 and 35° C., and wherein the amount of the basic precursor gives a pH at the end of precipitation in the reaction medium comprised between 7.5 and 9.5,
• b) washing and filtering the boehmite precipitate obtained in a),
• c) putting the precipitate obtained in b) in contact with at least one lithium source thereby obtaining a suspension,
• d) filtering the suspension obtained in c) thereby obtaining a slurry,
• e) drying the slurry obtained at the end of d) at a temperature comprised between 20 and 80° C.,
• f) shaping said dried slurry,
• g) drying the shaped material obtained at the end of f) at a temperature comprised between 20 and 200° C., and
• h) hydrothermally treating the dry shaped material obtained at the end of g) at a temperature comprised between 50 and 200° C.