How To Remove Static Charge from Powder: A Comprehensive Guide for Processors
How Does Static Build Up During Powder Processing?
Throughout processing, powder granules collide with each other and equipment. During these collisions, electrons transfer between materials, leaving one material with a positive charge and the other with a negative charge (like a balloon rubbing against your hair). This imbalance of electrons is what creates a static charge.
When the voltage difference between charged materials becomes large enough, electrons can suddenly jump through the air from the negatively charged surface to the positively charged one, creating a visible spark.
Powders are especially prone to this electrostatic risk. Each tiny particle has its own surface that can accumulate charge, and when you have millions of particles, the total charging potential is much greater than with solid materials. However, not every type of powder is the same. Here are a few key factors you should consider about your operation.
Some Powders Are More Prone To Static Accumulation
Certain types of powders are more prone to static charge than others. This is measured by a Minimum Ignition Energy (MIE) value — the lowest amount of electrical energy required to ignite a combustible dust cloud. The lower the MIE, the more dangerous. For example, only a small amount of energy is needed to ignite Magnesium Stearate dust while more energy is required to ignite Atomized Aluminum dust.
Humidity Helps Reduce Static
Humidity control is one of the simplest ways to remove static charge from powder materials. Low-humidity environments increase static buildup because there is not moisture in the air to help dissipate charges. This is why static problems are often worse in winter or in climate-controlled facilities.
More Movement = More Static
Higher processing speeds and more particle movement lead to more collisions and greater charge buildup. The electrostatic risk of a process is measured by a Mass Charge Density value — how much electrical charge accumulates per unit mass of powder material. Higher mass charge densities indicate greater static accumulation and thus, higher risk of discharge events.
What Are the Warning Signs of Static Build-Up?
There are several key warning signs that indicate dangerous levels of static buildup in powder processing:
Physical Signs:
- Powder particles clinging to equipment surfaces or forming clumps
- Visible dust attraction to surfaces
- Materials “jumping” or repelling when brought close together
- Fine particles dispersing unusually or creating dust clouds
- Powder flow problems or blockages in equipment
Sensory Signs:
- Crackling or snapping sounds from equipment
- Tingling sensation when approaching equipment
- Hair standing up on arms when near processing areas
- Small shocks when touching equipment or other surfaces
Equipment/Process Signs:
- Unexpected equipment malfunctions, especially electronic controls
- Inconsistent weight measurements
- Erratic behavior of level sensors
- Process control instruments showing unusual readings
- Filter systems showing reduced efficiency
- Product quality issues like uneven coating or agglomeration
How To Remove Static From Powder
There are a few ways to remove static charges from powder operations. Depending on the types of powder and processes you’re working with, you may need a combination of these solutions.
Grounding Straps
Grounding straps help eliminate static buildup by providing a safe pathway for accumulated electrical charges to dissipate. When static charges build up on processing equipment, the grounding strap conducts the excess electrons through its conductive material.
However, it’s important to note that grounding straps alone may not be sufficient for complete static control in powder processing because they only ground the equipment, not the powder itself. Insulating powders can still accumulate charge even in grounded equipment.
Static-Dissipating Flexible Connectors
One vulnerable part of a powder processing line is flexible connections between processing equipment. As powder flows through these connections, it can generate electrostatic build-up on the non-conductive material of the connector. This build-up can eventually create a spark discharge capable of igniting flammable gases or dust, leading to potential explosions.
To mitigate this risk, it’s crucial to use flexible connectors made from static dissipative materials — like BFM® fittings. When static charges build up, BFM® fittings channel the charges toward grounded equipment parts, preventing charge accumulation at any single point.
But how? To understand how static dissipative material works, you first need to understand surface resistivity — the measure of how fast a charge travels across the surface of a material.
The lower the surface resistivity, the faster a charge travels. For example, metal has a low surface resistivity and conducts electricity quickly. On the other hand, silicon has a high surface resistivity and holds onto electric charges. Static dissipative materials are in the middle. Their surface resistivity is low enough to allow charges to move through but high enough to prevent rapid discharge that could cause sparking.
BFM® fittings offer several different types of static dissipative flexible connectors, including the Seeflex 040AS Anti-Static Sleeve which is designed specifically for static-prone areas.
Upgrade Your Static Safety
While static buildup is an inevitable challenge in powder processing, there are easy solutions. With the right combination of powder static removal solutions, including proper grounding and static-dissipative connectors, you can more effectively manage static in your powder processing operation.
Plus, BFM® fittings provide a 100% dust-tight seal, preventing dust leakage and contamination, which further enhances safety and hygiene in the processing environment.
Don’t let static electricity put your operation at risk. Explore BFM® fittings’ range of safety features and static control solutions to protect your equipment, product quality, and, most important, your team’s safety.
