Akzo Nobel N.v.

Mateo Jozef Jacques Mayer

René Lodewijk Maria Demmer

Cornelis Elizabeth Johannus Van Lare

Jan Barend Westerink

Gerrald Bargeman

Boris Kuzmanovic

Maarten André Irène Schutyser

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

The invention relates to a process to produce brine of improved purity wherein a salt source, contaminated with sulphate ions and alkaline (earth) metal ions, is dissolved in water in the presence of an effective amount of a retarding agent comprising at least one low and at least one high molecular weight retarding agent. Said retarding agent effectively reduces the level of the alkaline (earth) metal sulphate dissolved in the brine, particularly the amount of calcium and sulphate. Preferably, the combination of the low and high molecular weight retarding agents is synergetic in the reduction of dissolved alkaline-earth metal sulphate.

Retarding agents for preparing purified brine

The invention relates to an evaporative crystallization process to make salt compositions that includes a step wherein a mother liquor is formed that contains an effective amount of a crystal growth inhibitor that is selected from oligopeptides, polypeptides, and polymers bearing two or more carboxylic acid groups or carboxyalkyl groups and optionally further phosphate, phosphonate, phosphino, sulfate, and/or sulfonate groups, such as carboxymethyl cellulose with phosphate groups, to form salt crystals with a (111) face. The salt can be washed with a reduced amount of washing water while still containing lower amounts of K, Br, SO, and/or Ca. A wet salt can be obtained by partially drying the salt crystals that are formed.

Process to make high-purity wet salt

The invention relates to a process to produce brine of improved purity by dissolving salt that contains a calcium sulfate source in water, in the presence of a retarding agent, while using one or more co-retardants to bind contaminants that could interfere with the retarding agents.

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Amersfoort, Netherlands

Mateo Jozef Jacques Mayer