METHOD FOR CRYSTALLIZING SOLUBLE SALTS OF DIVALENT ANIONS FROM BRINE

摘要

The invention pertains to removing soluble alkali metal or ammonium salt of a divalent anion from brine comprising following steps: obtaining brine with NaCl-concentration between 150g/L and saturation in the presence or absence of a crystal growth inhibitor for NaCl (CGI-NaCl), or with NaCl concentration above saturation in the presence of a CGI-NaCl, said brine optionally comprising a crystal growth inhibitor for the alkali metal or ammonium salt of the divalent anion (CGI-DA) ; if necessary, acidifying the solution to pH<11.5; if the concentration of CGI-DA is less than 20 mg/L, adding CGI-DA to obtain at least 20 mg CGI-DA/L; subjecting the solution to a membrane filtration; if the concentration of CGI-DA in the concentrate from the separation is less than 20 mg/L, adding CGI-DA to obtain at least 20 mg CGI-DA/L; crystallizing the concentrate; removing the crystallized alkali metal or ammonium salt of the divalent anion.