PROCESSES FOR PREPARING LITHIUM HYDROXIDE

1 - 85 . (canceled)

86 . A process for preparing lithium hydroxide, said process comprising:

submitting an aqueous composition comprising lithium sulphate to an electrolysis or an electrodialysis under conditions suitable for converting at least a portion of said lithium sulphate into lithium hydroxide, wherein during said electrolysis or said electrodialysis, said aqueous composition comprising lithium sulphate is at least substantially maintained at a pH having a value of about 1 to about 4.

87 . The process of claim 86 , wherein said aqueous composition comprising lithium sulphate is submitted to an electrolysis.

88 . The process of claim 86 , wherein said aqueous composition comprising lithium sulphate is submitted to a monopolar membrane electrolysis process.

89 . The process of claim 86 , wherein during said electrolysis, said pH is at least substantially maintained at a value of about 2 to about 4

90 . The process of claim 86 , wherein said aqueous composition comprising lithium sulphate is submitted to an electrodialysis.

91 . The process of claim 90 , wherein during said electrodialysis, said pH is at least substantially maintained at a value of about 1 to about 2.

92 . The process of claim 86 , wherein said process is carried out by introducing said lithium sulphate into a central compartment, an aqueous composition comprising lithium hydroxide into a cathodic compartment, and an aqueous composition comprising sulphuric acid into an anodic compartment.

93 . The process of claim 92 , wherein during said process said aqueous composition comprising lithium hydroxide is at least substantially maintained at a concentration of lithium hydroxide of about 35 to about 70 g/L.

94 . The process of claim 93 , wherein during said process said aqueous composition comprising sulphuric acid is at least substantially maintained at a concentration of sulphuric acid of about 20 to about 50 g/L.

95 . The process of claim 94 , wherein during said process said aqueous composition comprising lithium sulphate is at least substantially maintained at a concentration of lithium sulphate of about 10 to about 20 g/L.

96 . The process of claim 95 , wherein during said process, temperature of said aqueous composition comprising lithium sulphate is at least substantially maintained at a value of about 20 to about 80° C.

97 . The process of claim 92 , wherein during said process said aqueous composition comprising lithium hydroxide is at least substantially maintained at a concentration of lithium hydroxide of about 45 to about 65 g/L.

98 . The process of claim 86 , wherein during said process electrical current is at least substantially maintained at a density of about 400 to about 3000 A/m 2 .

99 . The process of claim 86 , wherein during said process electrical current is at least substantially maintained at a density of about 400 to about 1000 A/m 2 .

100 . The process of claim 86 , wherein during said process electrical current is at least substantially maintained at a density of about 400 to about 600 A/m 2 .

101 . The process of claim 86 , wherein during said process electrical current is at least substantially maintained at a constant value.

102 . The process of claim 86 , wherein during said process voltage is at least substantially maintained at a constant value.

103 . The process of claim 86 , wherein an anolyte used during said process comprises ammonia.

104 . The process of claim 86 , further comprising adding ammonia in an anolyte used for said process, thereby generating an ammonium salt.

105 . The process of claim 86 , wherein said ammonium salt is (NH 4 ) 2 SO 4 .