How Do You Separate Steel From Back Mass?

Are you wondering how to separate steel from black mass? Are you questioning when is the best time in the battery recycling process to pull your steel out?

If so, you are in the right place. In this article, you will learn all about magnetic separation of black mass and the introduction and necessity of the delamination mill.

Magnetic Separation: When and How

After recovering the first cut of high-value black mass and drying the remaining shredded material, we are left with a mixture that still contains steel components. This is now the time to begin magnetic separation.

Preferred Setup: Drum Magnet with Vibratory Feeder

While there are several types of magnets used in this industry—such as the cross-belt, over-band, and standard drum magnets—our preferred setup is a drum-over magnet combined with a vibratory feeder. Here is why:

• As the material travels along the vibratory feeder, it jumps up toward the rotating drum magnet.
• Ferrous materials, like steel, are attracted and pulled over the drum to a separate collection area.
• Non-magnetic materials—such as copper, aluminum, black mass, and plastics—fall straight through, avoiding unnecessary losses.

This method offers a second chance drop for non-ferrous particles that might initially lift but do not fully adhere to the magnet, improving overall separation accuracy and reducing contamination.

Introducing the Delamination Mill

With the steel now removed, we move on to the next major step: delamination milling. The goal here is to further liberate and densify the remaining materials to enhance downstream separation.

Why a Dosing Feed Hopper Matters

Before material enters the delamination mill, it is essential to pass it through a dosing hopper. This hopper ensures the mill is consistently fed at full load, which is critical for efficient operation.

• The delamination mill is designed so that material rubs against itself during processing.
• If the mill is underfed, lightweight components (like thin copper foil or paper) may simply blow through the system without being processed.
• Full load ensures proper interaction, helping densify materials like ultra-thin copper foil (which can be as thin as a human hair), turning them into denser particles that can be successfully separated later.

Failing to feed the mill properly can result in fine, lightweight flakes that escape separation and end up in the baghouse or waste stream, ultimately reducing recovery rates.

So, What’s Next?

After the delamination mill, the material will be routed to a screener, where it is further classified by size and prepared for air separation. We will dive into this part of the process in Part Four of this battery recycling series.

Key Takeaways from Part Three:

• Perform magnetic separation only after your first black mass cut.
• Use a drum-over magnet with vibratory feeding for efficient and accurate steel removal.
• A dosing hopper is essential to ensure optimal delamination mill performance.
• Properly feeding the mill helps densify materials, improving downstream recovery.

If you have any questions, please be sure to contact us through the Let’s Chat button below and we will be in touch soon!