How to Process Green Boards

Do you have green boards you are thinking of processing? Are you trying to find out how exactly to process them so you can get their full value?

If so, you are in the right spot. In this article, you will learn about the best methods for recycling green boards, which are typically made of 40%+ copper. At the end, you will know how to effectively process these boards and whether or not it could be a revenue generator for you.

Understanding Green Boards

Green boards are very brittle but the fiberglass within them is particularly abrasive on equipment. This is why the equipment we use is designed to withstand these conditions better than conventional granulation plants. The processing begins with feeding the boards directly into a vertical mill.

Processing Steps

1. Feeding into a Vertical Mill
   • For unpopulated boards and smaller printed circuit boards, the first step is a direct feed into a vertical mill via a conveyor.
   • If the boards are populated (i.e., they have chips and other components), a shredder should be used first to break them down for easier processing in the vertical mill.
   • Larger boards containing heat sinks should go through a shredder and an eddy current before milling to remove bulky materials.
2. Screening Process
   • After the vertical mill, the material is sent through a single-deck screener, which creates two separations:
     • Fine fraction: This will contain copper and circuit board dust, which resembles a fine pulp.
     • Larger fraction: Moves further along the process.
   • The fine dust is removed early to prevent unnecessary wear on the equipment.
3. Storage or Direct Processing
   • At this point, the fine copper and dust can either be stored for batch processing later or sent directly to an air table for separation.
4. Delamination / Turbo Mill Processing
   • The delamination mill (also known as a turbo mill) further processes the material by breaking it down into small particles.
   • The high-speed paddles delaminate the copper, preparing it for the second screening stage.
5. Second Screening
   • Another screening process is performed, similar to the first one.
   • The goal is to separate the materials further before sending them to the air tables.
6. Final Separation via Air Tables
   • If using one air table, the output will include a fine fraction similar to the previous step.
   • If using multiple air tables, the materials can be separated into distinct fractions for more efficient processing.
   • A double-deck air table setup provides three individual fractions, which can be helpful when processing populated boards containing white metals, brass, and other materials.

The Bottom Line

The best approach to processing green boards depends on factors such as budget and plant capabilities. Unpopulated boards are simpler to process while populated boards may require additional steps to separate non-copper materials effectively. By following these steps, you can maximize copper recovery while minimizing equipment wear and unnecessary waste. Let us know your thoughts through the Let’s Chat button below and we will be in touch!