Linda L Wilkins

US Patent:

57980462, Aug 25, 1998

Filed:

Aug 20, 1996

Appl. No.:

8/700000

Inventors:

Carol S. Greer - Lisle IL
Ann M. Capozzi - Naperville IL
Linda S. Wilkins - Naperville IL

Assignee:

Nalco Chemical Company - Naperville IL

International Classification:

C02F 124
C02F 156

US Classification:

210705

Abstract:

The present invention provides a method for removing secondary fiber contaminants from paper mill process waters comprising adding a polyvinyl chloride, a cationic polymeric coagulant and a polymeric flocculant to paper mill process waters containing secondary fiber contaminants in an amount sufficient to agglomerate the secondary fiber contaminants to larger particles sizes, and removing the secondary fiber contaminants from the process water by a dissolved air flotation clarification technique. The addition of particulate polyvinyl chloride in combination with a polymeric coagulant and flocculant prior to the DAF clarification process causes the contaminants to become preferentially coated with the polyvinyl chloride particles. This coating is what causes the subsequent removal of the secondary fiber contaminants in the DAF clarification process to be more effective.