Method of treating BCTMP/CTMP wastewater
AssigneeNalco Canada Inc.
InventorDaniel K. Chung
Life of this patent
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Abstract
A method of treating BCTMP/CTMP wastewater to improve retention and purification of cellulose fiber suspension and clarification of the BCTMP/CTMP wastewater which comprises the addition of a cationic, water soluble coagulant having a molecular weight less than 15,000,000 in an amount of about 1 to about 300 ppm; and a high molecular weight flocculant selected from the group consisting of: nonionic polymers having a molecular weight in the range between about 500,000 to about 30,000,000, low charge cationic polymers having a molecular weight in the range between about 5,000,000 to about 30,000,000, and low charge anionic polymers having a molecular weight in the range between about 5,000,000 to about 30,000,000, in an amount of about 0.1 to about 100 ppm.
Claims15
A method of treating bleached chemi-thermal or chemi-thermal mechanical pulp wastewater to improve retention and purification of cellulose fiber suspension and clarification of said wastewater by facilitating agglomeration of the cellulose fibers, which comprises the addition thereto of:
- a cationic, water soluble polymeric coagulant having a molecular weight less than 15,000,000 in an amount of about 1 to about 300 ppm;
- and
- a nonionic polyethylene oxide flocculant having a molecular weight in the range between about 500,000 to about 30,000,000, wherein said polyethylene oxide comprises:
- a particulate ethylene oxide polymer present in an amount of between about 20 to about 35% by weight;
- an inert liquid vehicle comprising a mixture of a glycol which is present in an amount between about 25 to about 30% by weight, and glycerine which is present in an amount between about 45 to about 50% by weight, wherein the specific gravity of said ethylene oxide polymer is approximately the same as the specific gravity of said inert liquid vehicle;
- and a suspension agent which is present in an amount between about 0.4 to about 0.6% by weight, wherein said polyethylene oxide has a viscosity in the range between about 1800 to about 5900 cps.
Dependencies are inferred from the claim text.