A pilot-plant for the selective recovery of magnesium and calcium from waste brines

The problem of brines disposal has raised great interest towards new strategies for their valorisation through the recovery minerals or energy. As an example, spent brine from ion exchange resins regeneration is often discharged into rivers lakes, thus impacting on process sustainability. However, such can be effectively reconcentrated, after removal bivalent cations, and reused regeneration. This work focuses developing testing a pilot plant selective magnesium calcium exploiting novel proprietary crystallization unit. part larger treatment chain complete brine, developed within EU-funded ZERO BRINE project. crystallizer was tested with retentate nanofiltration unit processing industrial water production Evides Industriewater B.V. (Rotterdam, Netherlands). Magnesium hydroxide were selectively precipitated by adding alkaline solution in two consecutive steps controlling reaction pH. Performance assessed terms efficiency purity produced crystals, observing most investigated cases about 100% 97% above 90% 96%, hydroxide, respectively.