Process of Producing Mineral Powder for Asphalt Concrete Pavement Surface Layer with Milling Equipment

Introduction

The production of mineral powder for asphalt concrete pavement surface layers is a critical process that directly impacts the durability, performance, and longevity of road infrastructure. Mineral powder, often derived from limestone, granite, or other hard rocks, serves as a filler in asphalt mixtures, enhancing stability, reducing voids, and improving resistance to moisture damage. The milling equipment used in this process must achieve precise particle size distribution, high purity, and consistent quality to meet stringent industry standards. This article explores the comprehensive process of producing mineral powder for asphalt concrete applications, highlighting the role of advanced milling technologies and recommending suitable equipment from our product portfolio.

Raw Material Selection and Preparation

The first step in producing mineral powder is the selection of appropriate raw materials. Typically, limestone is preferred due to its abundance, hardness, and compatibility with asphalt binders. The raw material must be free from impurities such as clay, organic matter, or soft minerals that could compromise the final product’s quality. After quarrying, the raw stones are crushed into smaller fragments using primary crushers (e.g., jaw crushers) to achieve a size suitable for milling equipment, usually below 50mm. Pre-screening may be employed to remove oversized particles and ensure uniform feed to the milling system.

Grinding Process: Key Stages and Equipment

The grinding process is the core of mineral powder production, where coarse particles are reduced to the desired fineness (typically ranging from 45μm to 5μm). This stage involves multiple steps, including coarse grinding, fine grinding, and classification. Advanced milling equipment, such as vertical roller mills, trapezium mills, and ultrafine mills, is employed to achieve high efficiency and precision.

Coarse Grinding

Coarse grinding reduces the crushed raw material to a medium fineness (e.g., 600-45μm). Equipment like the MTW Series Trapezium Mill is ideal for this stage due to its high capacity and robust design. With an input size of ≤50mm and output fineness adjustable from 30 to 325 mesh (0.038mm), the MTW mill combines grinding, classification, and conveyance into a single system. Its curved air duct design minimizes energy loss, while the wear-resistant shovel blades reduce maintenance costs. For instance, the MTW215G model handles 15-45 tons per hour, making it suitable for large-scale production lines.

Fine and Ultrafine Grinding

For applications requiring extremely fine powder (e.g., 2500 mesh or 5μm), ultrafine grinding equipment is essential. Our SCM Series Ultrafine Mill excels in this regard, offering output fineness from 325 to 2500 mesh (D97 ≤5μm) with high efficiency and low energy consumption. The mill features a vertical turbine classifier for precise particle size control and a pulse dust collection system that ensures environmental compliance. Models like the SCM1680 can process up to 25 tons per hour, making it a top choice for high-capacity operations. Additionally, the mill’s intelligent control system automatically adjusts parameters to maintain consistent product quality.

Classification and Collection

After grinding, the powder undergoes classification to separate particles based on size. Dynamic classifiers, such as those integrated into the SCM and MTW mills, use centrifugal force and airflow to achieve sharp cuts and prevent coarse particles from contaminating the final product. The classified fine powder is then collected using cyclone separators and pulse-jet bag filters, which ensure high efficiency (up to 99.9%) and minimal dust emissions. This step is crucial for meeting the strict fineness requirements of asphalt concrete fillers, where uniformity directly affects mixture performance.

Quality Control and Testing

Quality control is integral to the production process. The mineral powder must adhere to standards such as ASTM D242 or AASHTO M17, which specify fineness, plasticity, and chemical composition. Regular testing using laser particle analyzers, sieve analysis, and moisture detectors ensures consistency. The milling equipment’s automation capabilities, such as those in the SCM Ultrafine Mill, facilitate real-time monitoring and adjustments, reducing human error and enhancing product reliability.

Environmental and Economic Considerations

Modern milling equipment prioritizes sustainability through energy-efficient designs and low emissions. For example, the SCM Ultrafine Mill consumes 30% less energy than traditional气流mills and operates at noise levels below 75dB. Similarly, the MTW Trapezium Mill features pulse除尘 technology that exceeds international environmental standards. These advancements not only reduce operational costs but also align with global green manufacturing initiatives.

Conclusion

The production of mineral powder for asphalt concrete pavement surface layers demands precision, efficiency, and reliability from milling equipment. From coarse grinding to ultrafine processing, advanced mills like the MTW Series Trapezium Mill and SCM Series Ultrafine Mill offer tailored solutions that meet the industry’s rigorous requirements. By integrating these technologies, producers can achieve high-quality mineral powder that enhances asphalt performance while optimizing energy use and environmental impact. For detailed specifications and technical support, explore our product range to find the ideal equipment for your needs.