Akzo Nobel N.v.

Maarten André Irène Schutyser

Cornelis Elizabeth Johannus Van Lare

René Lodewijk Maria Demmer

Jan Barend Westerink

Gerrald Bargeman

Boris Kuzmanovic

Mateo Jozef Jacques Mayer

Antoon Ten Kate

The present invention relates to process to prepare a chlorine-containing compound using an aqueous salt solution containing at least 100 g/l of sodium chloride and a contaminating amount of polyvalent cations comprising the steps of (i) preparing an aqueous salt solution containing at least 100 g/l of sodium chloride and at least 0.01 ppm of polyvalent cations by dissolving a sodium chloride source in water, (ii) adding an effective amount of at least one positive retention enhancing component to the aqueous solution, (iii) subsequently subjecting the solution to a nanofiltration step, thereby separating the solution into a retentate which is enriched for polyvalent cations and a permeate which is the purified aqueous salt solution, (iv) reacting the chloride anions in the permeate to a chlorine-containing compound by an electrolysis step, and (v) recycling at least part of the retentate to dissolution step (i).

Process to prepare chlorine-containing compounds

The present invention relates to a process to prepare salt comprising the following steps: (i) preparing an aqueous salt solution containing at least 100 g/l of sodium chloride and at least 0.01 ppm of polyvalent cations by dissolving a sodium chloride source in industrial water, (ii) adding an effective amount of at least one positive retention enhancing component to the aqueous salt solution, (iii) subsequently subjecting the solution to a nanofiltration step, thereby separating the solution into a retentate which is enriched for the polyvalent cations and a permeate which is the purified aqueous salt solution, and (iv) concentrating the permeate to produce salt.

Process to prepare salt

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 absense of a cyrstal growth inhibitor for NaCl(GCI-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, acidify the solution to pH&#x3c;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 concentration from the separation is less than 20 mg/L, adding CGI-DA to obtain at least 20 mg CGI-DA/L; crystalling the concentration; removing the crystallized alkali metal or ammonium salt of the divalent anion.

Method for crystallizing soluble salts of divalent anions from brine

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Wageningen, Netherlands

Maarten André Irène Schutyser