The Eddy Current Separator (ECS) is the primary revenue-generating engine in any Incineration Bottom Ash (IBA) Sorting Plant. Using advanced high-frequency electromagnetic induction, it is purpose-built for the accurate separation of valuable non-ferrous metals—such as aluminum, copper, zinc, and brass—from inert WtE (Waste-to-Energy) slag.
Incineration bottom ash is notoriously difficult to process due to its varying moisture content, broad particle size range, and abrasive nature. Standard ECS units often struggle or burn out under these conditions. Our customized IBA Eddy Current Separators are engineered with robust eccentric rotors, reinforced Kevlar belts, and precision splitter plates.
Capable of achieving recovery rates of ≥ 98%, our ECS units turn municipal solid waste residue into highly profitable commodity streams (ZORBA), while simultaneously cleaning the slag for use as secondary construction aggregates.
Core Working Principle: The Lorentz Force in Action
Eddy Current separation relies on the electrical conductivity of metals. It is the critical step following primary Electromagnetic Separators, which must remove all ferrous (iron) materials first to protect the ECS rotor.
- High-Speed Magnetic Field: A high-strength NdFeB (Neodymium) magnetic rotor spins at extreme speeds (up to 4,000 RPM) inside a non-metallic drum, creating a high-frequency alternating magnetic field.
- Eddy Current Induction: As conductive non-ferrous metals (like aluminum chunks or fine copper wires) pass over this field, swirling "eddy currents" are induced within the metal particles.
- Magnetic Repulsion: These eddy currents generate their own magnetic field, which opposes the rotor's field, creating a strong repulsive force (known as the Lorentz force).
- Physical Separation: The non-ferrous metals are physically ejected forward over an adjustable splitter plate, while inert slag, glass, unburned organics, and plastic fall naturally due to gravity.
Core Advantages for WtE Slag Processing
Processing IBA requires equipment that can withstand high abrasion and prevent fine iron dust build-up. Here is how our ECS units are optimized for the task:
| Advantages |
Specific Benefits for IBA Sorting |
| ✅ Eccentric Rotor Design |
Crucial for fine IBA. The magnetic field is offset to drop off at the bottom of the drum. This prevents residual micro-iron dust from wrapping around the drum, heating up, and burning the conveyor belt. |
| ✅ Multi-Axis Splitter Plate |
The discharge parabolas of wet vs. dry slag vary greatly. Our splitter blades can be precisely adjusted horizontally and vertically to capture non-ferrous particles as small as 2mm without drawing in inert ash. |
| ✅ Extraordinary Recovery (≥ 98%) |
Optimized NdFeB multi-pole magnetic systems create deep fields, ensuring high-purity extraction of both large aluminum chunks and fine copper wires liberated by Cone Crushers. |
| ✅ Heavy-Duty Environment Protection |
Features an IP54 protection level, heavy-duty steel frames, and self-supporting C-shaped cantilever frames that allow for rapid belt replacement in under 15 minutes, minimizing downtime. |
Prerequisites for Maximum Separation Efficiency
To achieve the highest purity and recovery rates of non-ferrous metals, the feed material must be properly prepared before entering the Eddy Current Separator:
- ✔ Particle Size Ratio: The prerequisite for an optimal separation result is that the ratio of upper to lower grain size in the feed material should not exceed a value of 3 (e.g., feeding 5-15mm or 10-30mm batches). Use our Trommel Screens for precise pre-sizing.
- ✔ Uniform Feeding: A vibratory feeder must be used to ensure the slag is spread in a single, even layer across the ECS belt. Material stacking will trap metals and reduce the ejection trajectory.
- ✔ Strict Ferrous Removal: Heavy iron blocks can physically damage the Kevlar belt and drum. Strong overband magnets or magnetic drums must precede the ECS.
Eddy Current Separator Technical Specifications
| Specification Item |
Description / Value |
| Sorting Efficiency (Recovery Rate) |
≥ 98% |
| Target Particle Size |
Coarse Models: >40mm | Standard Models: 5-40mm | Fine Models: 2-10mm |
| Processing Capacity |
8 - 30 m³/h (Varies based on belt width and IBA density) |
| Belt Width Options |
400 / 600 / 800 / 1000 / 1200 / 1500 / 2000 mm |
| Rotor Speed |
Up to 3,000 - 4,000 RPM (Depending on pole system) |
| Control & Adjustment |
PLC Touch Screen with Variable Frequency Stepless Speed Control |
| Protection Class |
IP54 |
Note: Our engineers will recommend the optimal magnetic pole system (Coarse vs. Fine pole) and rotor configuration (Concentric vs. Eccentric) based on your specific material analysis.
Frequently Asked Questions (FAQ)
Q: Can the Eddy Current Separator extract heavy metals like stainless steel or lead?
A: Eddy current separation efficiency depends on the ratio of a metal's electrical conductivity to its density. Lightweight, highly conductive metals like aluminum and copper have excellent ratios and are easily thrown by the Lorentz force. However, heavy metals with poor conductivity (like stainless steel, lead, and thick brass) do not react strongly and will fall with the inert slag. To recover these, we route the remaining slag to our Sawtooth Wave Jig or induction sorting systems.
Q: How do you handle fine, wet IBA that sticks to the belt?
A: Wet, fine-grained WI (Waste Incineration) bottom ash changes the discharge parabola because the moisture causes the material to stick slightly to the belt. Our ECS units designed for wet processing feature specifically calibrated multi-axis splitter blades and integrated belt-cleaning brushes to prevent build-up and maintain high separation accuracy.
