초록 ▼

A process for treating alkaline solutions obtained from lithographic printing plate processing comprises admixing at least one alkaline solution and at least one acidic solution in the presence of at least one aqueous solution to obtain a discharge solution having a pH in the range of about 5.0 to 1

A process for treating alkaline solutions obtained from lithographic printing plate processing comprises admixing at least one alkaline solution and at least one acidic solution in the presence of at least one aqueous solution to obtain a discharge solution having a pH in the range of about 5.0 to 11.5. Another process for treating alkaline solutions obtained from lithographic printing plate processing comprises admixing at least one alkaline solution and at least one aqueous waste water solution to obtain an aqueous alkaline solution, and admixing the resultant aqueous alkaline solution with at least one acidic solution to obtain a discharge solution having a pH in the range of about 5.0 to 11.5, and to control systems for such processes, and methods of controlling such processes. The alkaline solution has a pH greater than 7.0, preferably greater than about 12.5, and the acidic solution has a pH less than 7.0, preferably less than about 2.5. The alkaline, acidic and aqueous solutions are admixed in volume ratios in the range of about 1 part alkaline: 0.2-4.0 parts acidic: .gtoreq.50 parts aqueous. The invention advantageously avoids the formation of unacceptable gels, sludge, or precipitate which typically occurs if the acidic solution is used to neutralize the alkaline solution.

대표청구항 ▼

[ We claim:] [1.]1. A process for treating an effluent alkaline solution obtained from lithographic printing plate processing comprising admixing at least one alkaline solution and at least one acidic solution in the presence of at least one aqueous solution in a volume ratio in the range of about 1

[ We claim:] [1.]1. A process for treating an effluent alkaline solution obtained from lithographic printing plate processing comprising admixing at least one alkaline solution and at least one acidic solution in the presence of at least one aqueous solution in a volume ratio in the range of about 1 part alkaline:0.2-4.0 parts acidic:.gtoreq.50 parts aqueous, thereby neutralizing the alkaline solution to avoid the formation of unacceptable gels, sludge, or precipitates, and to obtain a neutralized discharge solution having a pH in the range of about 5.0 to 11.5.