Chlor-alkali electrolysis in inorganic chemicals

Chlor-alkali electrolysis produces the important commodity chemicals chlorine, hydrogen and caustic soda from sodium chloride and water. The purity of the end products is central to all the process stages. The basic substance is brine. At the start, the brine saturation is set by precipitation, filtration and preliminary purification of the brine. As the electrolysis consumes vast amounts of energy, process efficiency is of particular importance. The modern membrane electrolysis process, which is becoming increasingly popular across the globe, uses much less energy and is less polluting than conventional electrolysis processes – while maintaining a similar level of purity of the end products dry chlorine, hydrogen and caustic soda. However, the membrane process requires the brine used and circulating in the process to be of very high quality. Furthermore, all of the processes attempt to separate the chlorine gas produced from the hydroxide to effectively avoid a back reaction from chlorine to chloride and hypochlorite, as this would contaminate the caustic soda. One of the key process parameters here is the optimal temperature setting. All of this is crucial for composition and concentration of the caustic soda formed.

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