Model DF-978

DF-978 is a proprietary single-step liquid used to effectively precipitate dry-film photo-resist from alkaline developer and stripper solutions typically found in the printed circuit manufacturing and photo-chemical machining industries.

Conventionally, wastewaters containing dry film have been treated with a variety of methods in an effort to achieve precipitation. While marginally effective, the byproducts generally were commingled with other wastewaters, adding to the volume of hazardous waste generated on an annual basis, as well as making compliance with local discharge permits difficult.

Through waste stream segregation, wastewaters containing dry film can now effectively be treated, thereby reducing the burden on the production treatment process, while minimizing waste and maintaining compliance.

What You'll Need

Dry-film resist precipitation as well as chelated metals destruction can be carried out in a simple batch tank process.

• Conical mixing tank with bottom drain valve and stand (Note: Minimum tank size should accommodate two days' production of solution)
• Industrial mixer, with shaft length to reach the bottom of the tank
• pH controller with high/low set point
• Dewatering equipment: (typically plate/frame filter press)

How You'll Do It

DF-978 lets you effectively precipitate dry-film in a simple, yet reliable and rapid manner:

1. Fill holding tank with developer/stripper solution.
2. Turn on mixer, (leave on throughout process).
3. Add DF-978 liquid in the ratio of 1 liter of DF-978 to 300 gallons of solution to be treated.
4. Let mix for 5 minutes.
5. Turn on pH controller and slowly acidify with Sulfuric Acid (Tech Grade) to a pH = 4.0 (Note: Stop the acidification process when the top foam layer exceeds two inches. Wait 5 minutes and resume process.)
6. Let mix for 10 minutes.
7. Open bottom tank valve and process through the filter press.