Recovery of lithium hydroxide from spent lithium carbonate using crystallizations

Recovery of LiOH from the spent Li2CO3 used as absorbent for carbon dioxide in breathing apparatus was successfully explored by precipitation and crystallization. A lithium hydroxide solution was prepared by precipitation of calcium carbonate using reaction of spent Li2CO3 and calcium hydroxide. The effects of the operating conditions on the reaction were investigated. Conversion of calcium carbonate was about 95%. Lithium hydroxide monohydrate from lithium hydroxide solution was obtained in batch evaporative crystallization. The effect of the evaporation rate on crystal morphology was investigated. The evaporation rates were affected to control size and yield of crystals. Eventually, the purity of crystals was above 99wt% and yield was about 80%.