Reverse osmosis (RO) desalination is the most economically viable process to produce potable water in bulk capacity in recent years. However, lack of environment friendly RO concentrate management particularly at inland sites, has been a major concern to the concerned authorities of the nation worldwide. Brine mining is a new concept that provides an attractive solution for seawater RO brine (SWRO) management, yet the cost-effective technology for brine concentration and mineral recovery is a challenge that puts a check on the widespread implementation of the brine mining and mineral recovery strategy. Water Technologies Innovation Institute and Research Advancement (WTIIRA) recently introduced an innovative process scheme utilizing an osmotically assisted reverse osmosis (OARO) membrane system to concentrate SWRO brine and recover dissolved minerals. Building upon this, a demonstration brine mining plant has been designed and is under construction in the city of Haql, Saudi Arabia. The plant is being constructed in two phases. The first phase aims to produce 6–10 tons/day of high purity sodium chloride (NaCl) salt continuously, while the second phase will produce 6–8 kg/day of liquid bromine (Br) and 100 kg/day of magnesium (Mg) metal from SWRO brine. This paper details the design of processes involved in the first phase of the Haql brine mining project which facilitates the enhancement of water recovery, increase in brine concentration, precipitation, and recovery of thermally crystallized NaCl salt. It also presents capital cost and energy consumption estimates for the demonstration plant which paves the way towards upgrading the commercial plant for production of salts and minerals from seawater. The novel processes used in this plant also contribute towards the sustainable and circular economic goals of Saudi Arabia.
Mustafa et al. (Wed,) studied this question.