Salt recycling of mother liquor

EBNER designed, delivered and installed a processing plant for the so-called mother liquor at a salt refinery. The salt refinery treats raw brine to saleable table salt or road salt by different process steps.

In the primary cleaning processes the impurities like potassium or bromide, which are included in the raw brine, cannot be removed completely. Sulphate ions are only partially separated depending on their solubility. Therefore during evaporation- and crystallization processes these substances have to be discharged (elutriated out of the system) in soluble condition. In the past the salt refinery has elutriated this mother liquor into the environment.

In the plant designed by EBNER and a partner also the product potassium sulphate – being well marketable – can be produced from the mother liquor in addition to the NaCl-salt. This process is unique worldwide.
It consists of the following process steps:

  • neutralisation
  • evaporation crystallization, sodium chloride-production
  • cooling crystallization, Glaserite production
  • conversion of sodium sulphate and potassium chloride to potassium sulphate, K2SO4-production
  • drying and storage of potassium sulphate