Industrial Background

Recent years, the non-ferrous metal recycling industry grows fast, and various related industries are highly developed. Different types of eddy current separator with varying quality have continuously entered the market, but due to inherent limitations, they have very limited functionality in practice. Some are only capable of sorting fine material and cannot handle coarse material, while others can only separate coarse material but not fine material. As a result, users have to choose different types of eddy current separator based on different material properties, which increases procurement costs. Additionally, some eddy current separator can only separate non-ferrous metal from other metal but not to separate ferrous metals. Therefore, the users have to purchase other magnetic separation equipment for further separation, prolonging the processing line and failing to meet market demands.

General Introduction

Eddy Current Separator is mainly used to separate non-ferrous metals from non-metallic materials and ferrous metals. It is based on two important physical phenomena: an alternating magnetic field that varies with time always accompanies an alternating electric field (Faraday's law of electromagnetic induction); a current-carrying conductor generates a magnetic field (Biot-Savart law). When a conductive non-ferrous metal passes through a high-frequency alternating magnetic field, an eddy current is induced in the non-ferrous metal. This eddy current itself generates a magnetic field in the opposite direction to the original magnetic field. As a result, the non-ferrous metal is repelled by the magnetic force and flies forward along its conveying direction, thus realizing the separation from other non-metallic substances.

Principle of Separation:

It is a separation technique using different electrical conductivities of different material. With the high-speed rotation of a permanent magnetic rotor, generating an alternating magnetic field. When metals with electrical conductivity pass through the magnetic field, eddy current is induced inside the metal. The eddy current  will generate an alternating magnetic field that is opposite to the direction of the magnetic field of the magnetic rotor. Non-ferrous metals, such as aluminum and copper, will be repelled and jumping off along the conveyor belt direction and separated from other non-metallic materials such as glass and plastic, achieving the goal of separation.

Magnetic Rotor Design:

Concentric Rotor Design

The concentric roller design will generate a uniform eddy current field over the entire magnetic drum surface, with a larger magnetic wrapping angle. For materials such as PET flakes, plastic flakes and etc., the concentric roller design provides better results than eccentric rotor design does.

Eccentric Roller Design

Eccentric roller design with an eccentric magnetic roller inside non-conductive drum,  is concentrating eddy current forces within the separation area at the end of the belt. The eccentric design allows more ferrous material, reducing wearing and overheating caused by the accumulation of ferrous metals on the magnetic rotor. The magnetic rotor is installed at the top of the drum, concentrating the magnetic force at the top surface of drum. Compared to concentric rotor design, even though the magnet wrapping angle is smaller, ferrous metals are easier to dislodge after passing through the magnetic rotor, reducing accumulation issues at the bottom of the drum and minimizing belt wearing.

Advantages of Eccentric Rotor Design

• Rare-earth magnet provides a strong eddy current field.

• Adjustable magnetic rotor position for optimal separation.

• Reducing long-term wearing caused by the accumulation of ferrous metals.

• Compact design, space saving.

• Convenient inspection window for easy maintenance.

Product Features

® Easy operation, automatic separation of non-ferrous and ferrous metal.

® Easy installation, easy connecting to both new or existing processing line.

® Simple and flexible adjustments for optimal separation with low energy consumption.

® Special magnetic field design results in a higher magnetic field on the belt surface.

® Magnetic system treated for corrosion resistance, with a demagnetization rate -2% within 20 years.

® Automatic centralized lubrication system with level control and pipe blockage alarm, reducing labor intensity.

® Control system applying inverters, PLC control, offering manual, automatic, remote, and on-site operation modes.

Product Advantages

• Support Frame: High-quality carbon steel frame.

• Drive Configuration: Nord reduction motor, NSK bearings, Siegling belts.

• Magnetic Rotor: 6mm fiberglass cylinder, 1.2mm sealed cylinder, 25mm thick tile-shaped magnetic blocks, 4500Gs on belt surface, demagnetization rate -2% within 20 years.

• Automation: Centralized lubrication (level alarm, pipe blockage alarm), PLC, inverter.

• Intelligent Electrical Control: Temperature controller, on-site operation, remote control, manual control, automatic control.

Factors Affecting Separation Efficiency

• Repulsion Force: Magnetic field intensity, alternating frequency of magnetic field, conductivity, mass, density, material shape.

• Feeding Method: Ensure even and non-overlapping material feeding.

• Material Granularity: Uniform particle size, not too fine.

• Baffle(Material Splitting Plate) Position and Thickness: The thinner the splitting line, the better separation result.

• Belt Speed: Belt speed, material through-put and rotor speed are adaptive to each other properly.

Product Application:

• Separation of non-ferrous metal and non-metal from aluminum waste, including aluminum cans and ferrous metal.

• Separation of non-ferrous metal from bottom ash of furnace.

• Recycling non-ferrous metal from crushed material of automobiles disassembling plant.

• Separation of aluminum and copper from aluminum-copper casting sand and melting process.

• Removal of aluminum bottle caps from crushed glass and plastic bottles.

• Recycling non-ferrous metal from incinerated printing plates.

• Recycling non-ferrous metals from municipal waste and incinerated household waste.

• Electronic waste processing.

• Sorting of non-ferrous metals from large crushed items such as old cars, appliances, and gaming consoles.

• Eddy current separation is also highly essential in the waste recycling facilities for recycling non-ferrous metal.