Abstract:
Currently, sodium hydroxide as well as other chlor-alkali products used in Ghana and the
entire ECOWAS sub-region is imported in spite of the huge salt potential as raw material
available in Ghana. This study sought to produce sodium hydroxide (NaOH) from solar
salt in Ghana using the membrane cell process. Sodium stearate solution was used as
alternative brine purification for calcium and magnesium impurities present in the salt.
Sulphate impurities were also precipitated with calcium chloride. The electrolytic
membrane cell consisted of carbon and stainless-steel electrodes separated by Nafion 117
membrane. Titration methods were then used to analyse the electrolytic products and it
was established that the impure solar salt contained 6030 ppm, 1920 ppm, 1030 ppm and
0.43 ppm of sulphate, calcium, magnesium and iodine impurities respectively. It was also
realised that for each batch of purification, an optimal sodium stearate solution per 1 litre
of brine solution required was 200g. Five brine concentrations i.e. 27 wt%, 28 wt%, 29
wt%, 30 wt% and 31wt% were prepared and used for the electrolysis. However, the 29
wt% brine concentrations produced the highest amount of sodium hydroxide of 6.1g at the
fifth hour at a current efficiency of 44.92%.This study concludes that solar salt mined in
Ghana is suitable for the production of sodium hydroxide using the membrane cell
process
