Schemes for salt recovery from seawater and RO brines using chemical precipitation

AbstractDisposal of brines from seawater desalination plants affects marine ecology and significant financial burdens. Recovery of salts from brines improves both sides of the problem and avails opportunities for new state of the art desalination/salt production complex. Three important separation processes could be adopted to formulate the corner stones for state-of-the-art salt recovery production line, namely chemical treatment, nanofiltration (NF), and ion exchange. This paper explores the performance of selected precipitants on saline solutions presenting synthetic seawater, natural seawater, and two reverse osmosis (RO) brines obtained from desalination plants located on Mediterranean (B1) and Red Sea (B2) shores. Sodium carbonate enabled 95.5, 89, and 95% recovery of calcium (Ca) seawater, Mediterranean, and Red Sea RO brines, respectively. While, values of magnesium (Mg) recovery from chemically treated schemes lie between 85.6 and 91.3%. Also, phosphate precipitation enabled two-stage recovery of...

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