Salt Recovery Plant

A Salt Recovery Plant recovers reusable inorganic salts from the concentrated brine that a Zero Liquid Discharge (ZLD) plant produces, instead of sending that brine to an evaporation pond or hazardous-waste landfill as mixed salt cake. By evaporating the brine to saturation and then crystallising, separating, and drying the salt, it converts what is otherwise a disposal liability into a clean, dry, saleable or reusable product such as sodium sulphate or sodium chloride.

This is the resource-recovery end of the ZLD chain. After Multiple Effect Evaporators and Mechanical Vapour Recompression concentrate the effluent, the salt recovery stage takes over: a forced circulation crystalliser drives the dissolved salt to form crystals, a centrifuge separates the salt slurry, and a dryer produces a free-flowing powder. Mother liquor is recycled back to the crystalliser to maximise yield and keep the purge stream small.

Recovering a single, reasonably pure salt is more valuable than producing mixed salt cake, so where the feed chemistry allows, selective, fractional, or cooling crystallisation is used to separate individual salts. Sodium sulphate, common in textile and some chemical effluents, and sodium chloride are the salts most often recovered. The result supports a circular economy: the recovered salt can be reused within the process, sold, or disposed of far more easily than a mixed hazardous residue.

Because ZLD brines are highly concentrated and often chloride-rich, metallurgy and crystalliser design are critical. Spans engineers salt recovery plants in duplex, super-duplex, or titanium as the chemistry demands, integrating evaporation, crystallisation, dewatering, and drying into a reliable train that closes the loop on a ZLD plant.