The process concerns hydrometallurgical processing of manganese sulphate and manganese dithionate containing liquors and recovery of water therefrom. Sodium sulphate and/or sodium dithionate containing liquors are derived from manganese sulphate and manganese dithionate containing liquids, which are then cooled to produce crystals of sodium sulphate decahydrate and sodium dithionate dehydrate. The sodium sulphate decahydrate and sodium dithionate dehydrate crystals are then heated to a temperature sufficient to decompose the sodium sulphate decahydrate crystals to form anhydrous sodium sulphate crystals, sodium dithionate hydrate crystals and water, after which water is removed from the sodium sulphate and sodium dithionate hydrate crystal. The sodium sulphate and sodium dithionate dehydrate crystals are then heated to form anhydrous sodium sulphate, sulfur dioxide and water or steam. The anhydrous sodium sulphate is then separated from the sulfur dioxide and water.