REGULATION OF CALCIUM CONCENTRATION IN REUSED PROCESS WATER FOR PAPERMAKING

Japanese Patent JP3134225

B2

PROBLEM TO BE SOLVED: To prevent the generation of dirt, caused by the increase in the rate of the reuse of process water, and the decrease in the activity of a polymeric additive for the paper manufacture in a method of adjusting calcium concentration in papermaking process water.
SOLUTION: A calcium concentration is adjusted by adding sodium carbonate or sodium hydrogen carbonate to white water circulated at a short term from a papermaking step to precipitate and remove calcium ion in the process water as calcium carbonate. In the removal of the precipitate of the calcium carbonate, the floatation processing method is carried out to remove the before precipitate, and the calcium carbonate not removed until the time is discharged from the paper making field by allowing the web to retain the not removed calcium carbonate to prevent the generation of calcium dirt and a calcium salt of a fatty acid by the reuse of the process water beforehand. In the process for removing the calcium carbonate, not only the dewaterability is improved by removing the calcium carbonate with minute components, and improving the efficiency of a polymeric additive for paper manufacture, but also the environmental pollution generation from the wastewater discharge is decreased, and the energy charged in the process water and the field is saved by closing the discharge of the process water.

Ryu Chung Yong
Jikyung Rak
Song Bong Kong
Shin Jung Ho
Osekyung

JP17608899A

February 13, 2001

June 22, 1999

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KOREA RESEARCH INSTITUTE OF CHEMICAL TECHNOLOGY

D21F1/66; C02F5/00; C02F5/02; C02F9/00; C02F1/24; (IPC1-7): D21F1/66; C02F5/00; C02F5/02

JP691295A
JP10180293A

Eiichi Saito (1 person outside)

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