Overview of Electrostatic Beneficiation:
Electrostatic beneficiation is a dry separation process that operates in a high-voltage electric field. This process utilizes the different electrical properties of minerals to selectively sort them. It finds application in the sorting of non-ferrous metals, iron ore, non-metallic ores, and other materials. Various techniques are employed, including electrostatic separation, electrical classification, friction-charged sorting, high-gradient separation, dielectric separation, and electrostatic precipitation.
Mineral Properties and Electric Field:
- Conductive Minerals: Examples include magnetite, ilmenite, cassiterite, and native gold.
- Non-Conductive Minerals: Examples include quartz, zircon, feldspar, calcite, scheelite, and silicate minerals.
High-Voltage Electric Field and Equipment Selection:
The choice of electrostatic separation equipment depends on both mineral properties and the requirements of the product. There are various types of electrostatic separation equipment tailored to different gravity separation processes based on ore characteristics.
Electrostatic Separation Sorting Process:
- Corona Release:
- The high voltage power supply induces corona release from the corona and electrostatic pole.
- Corona electrode ionizes air molecules, creating positive and negative ions.
- Space near the roller side is charged negatively.
- Mineral Charging:
- Mineral particles entering the field receive both negative and positive charges.
- Conductors’ charges are rapidly transferred, and non-conductors are impacted by the electrostatic field.
- Mineral particles induce negative charges, leaving only a positive charge.
- Mineral Separation:
- Mineral particles are attracted to the steering electrode due to opposite charges.
- Gravity and centrifugal force result in conductor mineral particles falling from the front roller, becoming the concentrate.
- Non-conductors, with interface resistance, retain negative charges and become tailings.
- Medium Mine:
- Minerals with conductivity between conductors and non-conductors fall into the medium mine category.
This process effectively leverages the principles of electrostatics to achieve mineral separation based on their electrical properties.