Recycling and Reuse Technology of Over-Sprayed Powder Coatings

In the electrostatic spraying process of powder coating, affected by workpiece structure, spraying angle, and electrostatic field effect, about 10%-30% of powder will form over-spray and float in the spraying room, failing to adhere to the workpiece surface. In traditional production modes, most manufacturers directly discard these over-sprayed powders, resulting in huge waste of raw materials and increased production costs. At the same time, random discharge of floating powder will cause air pollution and fail to meet environmental protection production standards. With the continuous improvement of industrial cost control and green production requirements, the efficient recycling and standardized reuse of over-sprayed powder have become essential core technologies for powder coating manufacturers.

The over-sprayed powder recovered from the spraying room has certain quality differences compared with fresh powder. During the floating and settling process, the recycled powder will mix with tiny dust, fiber impurities, and fine particle debris in the air. At the same time, the long-term suspension in the air will cause the powder to absorb trace moisture, resulting in slightly reduced fluidity. In addition, the particle size distribution of recycled powder is different from fresh powder: most of the oversized coarse powder and ultra-fine floating powder are concentrated in the recycled materials, which affects the spraying effect and film-forming performance if directly used.

Therefore, the recycling and reuse of over-sprayed powder must go through standardized post-processing procedures, and direct mixing and use are strictly prohibited. The complete recycling process includes four core steps: centralized collection, impurity filtration, particle size classification, and proportional reuse. First, use professional dust collection and recovery equipment to centrally collect floating over-sprayed powder to avoid secondary pollution. Second, filter out large impurities such as dust and fibers through multi-stage precision screening equipment to purify powder purity.

Third, carry out particle size classification and moisture removal treatment on the purified recycled powder. Remove unqualified ultra-fine powder and oversized coarse powder through air classification equipment, retain powder particles meeting spraying standards, and eliminate absorbed moisture through low-temperature drying treatment to restore powder fluidity. Finally, mix the processed qualified recycled powder with fresh powder in a scientific proportion to balance particle size distribution and functional performance.

In terms of proportioning standards, after a large number of production tests, the optimal mixing ratio of recycled powder to fresh powder is 1:3. This ratio can effectively balance the particle size distribution and fluidity of the mixed powder, ensuring that the spraying effect, leveling performance, and coating film quality are completely consistent with full fresh powder. Excessively high proportion of recycled powder will lead to unstable coating gloss, slightly reduced flatness, and increased fine particle defects, while excessively low proportion cannot achieve the purpose of cost saving.

TYOPSUN’s professional powder recovery system provides one-stop solutions for over-spray powder recycling. The high-efficiency pulse dust collector realizes 95%+ recovery rate of floating powder, with automatic dust removal and impurity filtration functions. The supporting air classification and drying equipment completes powder purification, particle size optimization, and moisture removal in one step. The intelligent proportioning system automatically mixes recycled powder and fresh powder according to standard ratios, realizing intelligent and standardized reuse.

The application of over-spray powder recycling technology can reduce the raw material waste rate of powder coating production by more than 25%, greatly lowering enterprise production costs. At the same time, it reduces powder dust pollution in the production workshop, improves the working environment, and meets national green environmental protection production standards. It is an efficient and low-cost optimization scheme for powder coating enterprises to realize cost reduction and efficiency improvement.