Optimization of High-Voltage Power Supplies in Material Identification for Electrostatic Separation

High-voltage electrostatic separation technology is a physical method that utilizes differences in the electrical properties of materials to achieve separation. It holds significant application value in fields such as resource recovery, mineral processing, and solid waste treatment. The core of this technology lies in the high-voltage power supply system, whose performance directly determines the separation efficiency and material identification accuracy. In recent years, with advancements in high-voltage power supply technology, the application of electrostatic separation in material identification has been significantly optimized.
The working principle of high-voltage electrostatic separation is based on differences in the electrical conductivity, dielectric constant, and rectification characteristics of different materials. In a high-voltage electric field, a corona electrode charges the particles. Conductive particles discharge rapidly and are separated by the centrifugal force of a grounded roller, while non-conductive particles remain adhered to the roller surface due to residual charge and are eventually removed by a brush . The stability, voltage accuracy, and frequency response of the power supply directly affect particle charging efficiency and separation accuracy. For example, when separating copper, aluminum, and PET from discarded solar cells, the voltage must be precisely controlled between 30–40 kV, and the roller speed must match the particle size (typically 85 r/min) to achieve a recovery rate exceeding 90% .
The key to optimizing material identification lies in the parameter control of the high-voltage power supply. Response surface experiments show that the interaction of voltage, electrode angle, electrode spacing, and roller speed significantly affects separation efficiency . For instance, when separating metals from circuit boards, the voltage must be set to 24 kV, and the electrode spacing to 5.2 cm, to balance grade and recovery rate . Secondly, the frequency characteristics of the power supply determine the stability of the electric field. High-frequency DC high-voltage power supplies can reduce ripple and avoid discharge fluctuations, thereby enhancing the identification ability of materials with subtle electrical differences . Additionally, modular power supply designs can adapt to complex working conditions (e.g., humidity variations) through multi-stage voltage stabilization and isolation circuits, ensuring consistent separation .
The influence of environmental factors such as humidity on separation effectiveness cannot be overlooked. Studies show that when relative humidity exceeds 70%, the surface conductivity of non-conductive particles increases, leading to reduced separation efficiency . Therefore, the high-voltage power supply system must integrate environmental monitoring modules to dynamically adjust the output voltage to compensate for humidity effects . On the other hand, material characteristics such as particle size distribution and liberation degree require the power supply to have adaptive capabilities. For multi-size mixed systems, a single electric field is insufficient for effective separation. Multi-stage separation equipment (e.g., double-roller separators) and optimized power supply sequences are needed to achieve step-by-step refinement .
In the future, the optimization of high-voltage electrostatic separation power supplies will focus on intelligent control and multi-technology integration. By introducing machine learning algorithms, the power supply can analyze material composition in real time and adjust parameters to improve separation accuracy for complex mixtures (e.g., electronic waste) . Meanwhile, high-frequency and compact power supply designs are expected to address the challenges of fine particle (<0.074 mm) separation, expanding its application in the field of nanomaterial separation . In summary, advancements in high-voltage power supply technology are driving electrostatic separation toward higher efficiency, precision, and environmental sustainability, providing core support for resource recycling.