A process (10) for the production of lithium hydroxide, the process comprising the steps of: (i) Causticising lithium chloride (12) with sodium hydroxide (16) to produce a lithium hydroxide product; (ii) Collecting the solids resulting from the causticisation of step (i) and filtering (22) same; (iii) The filtered solids from step (ii) are passed to a heating step (32) in which anhydrous lithium hydroxide is produced; (iv) Filtering (34) the anhydrous lithium hydroxide product of step (iii); and (v) Quenching the anhydrous lithium hydroxide of step (iv) with water to produce lithium hydroxide monohydrate crystals.
