Phosphogypsum Grinding Process and Comprehensive Utilization Technology

Introduction

Phosphogypsum, a by-product of phosphoric acid production in the fertilizer industry, presents both environmental challenges and valuable utilization opportunities. With annual global production exceeding 200 million tons, the proper treatment and utilization of phosphogypsum have become crucial for sustainable industrial development. This article explores advanced grinding technologies and comprehensive utilization methods that transform this industrial by-product into valuable resources.

Characteristics of Phosphogypsum

Phosphogypsum primarily consists of calcium sulfate dihydrate (CaSO₄·2H₂O) but contains various impurities including phosphates, fluorides, heavy metals, and organic matter. Its physical and chemical properties vary depending on the phosphate rock source and production process. The material typically exhibits moisture content of 20-30%, requiring proper drying before grinding operations. Understanding these characteristics is essential for selecting appropriate grinding equipment and utilization pathways.

Grinding Process Technology

Pre-treatment Requirements

Before grinding, phosphogypsum requires thorough washing to remove soluble impurities and drying to reduce moisture content below 5%. The drying process typically employs rotary dryers or flash dryers operating at temperatures between 150-300°C. Proper pre-treatment ensures optimal grinding efficiency and final product quality.

Grinding Equipment Selection

The selection of grinding equipment depends on the required fineness and production capacity. For coarse grinding applications requiring 30-325 mesh products, the MTW Series Trapezium Mill offers exceptional performance with its advanced curved air duct design and combined blade system. This equipment demonstrates remarkable efficiency in handling phosphogypsum with capacities ranging from 3-45 tons per hour.

For ultra-fine applications demanding 325-2500 mesh products, the SCM Ultrafine Mill provides superior grinding precision. With its vertical turbine classifier and special material roller and ring design, this mill achieves D97≤5μm fineness while maintaining energy efficiency 30% higher than conventional jet mills. The equipment’s intelligent control system automatically adjusts operational parameters to maintain consistent product quality.

Grinding Process Optimization

Optimal grinding parameters for phosphogypsum include controlled feed rate, appropriate air flow, and precise temperature management. The grinding system should incorporate efficient dust collection and classification to ensure uniform particle size distribution. Modern grinding systems utilize PLC-based automation to monitor and adjust operational parameters in real-time, maximizing efficiency and product consistency.

Comprehensive Utilization Technologies

Construction Materials Production

Ground phosphogypsum serves as an excellent raw material for various construction applications. When processed to appropriate fineness, it can replace natural gypsum in cement production as a set retarder. The material also finds application in gypsum board manufacturing, self-leveling floor compounds, and architectural elements. The consistent particle size achieved through proper grinding ensures optimal performance in these applications.

Agricultural Applications

Properly processed phosphogypsum provides valuable soil amendment properties. It improves soil structure, enhances water infiltration, and supplies calcium and sulfur nutrients. The grinding process must ensure appropriate fineness for optimal soil interaction and nutrient availability. Typical agricultural applications require grinding to 100-200 mesh for effective soil incorporation.

Advanced Material Synthesis

Recent technological advancements have enabled the conversion of phosphogypsum into high-value materials including calcium sulfate whiskers, ammonium sulfate fertilizers, and specialty construction composites. These applications often require ultra-fine grinding to specific particle size distributions, making the SCM Ultrafine Mill particularly suitable for such precision processing requirements.

Equipment Recommendations for Phosphogypsum Processing

SCM Ultrafine Mill for High-value Applications

For operations targeting high-value phosphogypsum products requiring ultra-fine specifications, the SCM Ultrafine Mill represents the optimal solution. Its advanced design features include:

• High-precision vertical turbine classifier ensuring accurate particle size control
• Special material grinding components providing extended service life
• Intelligent control system maintaining consistent product quality
• Environmental compliance with pulse dust collection efficiency exceeding international standards

The mill’s capacity range from 0.5-25 tons per hour accommodates various production scales, while its energy-efficient operation reduces operational costs significantly.

MTW Series Trapezium Mill for Construction-grade Products

For construction material applications requiring 30-325 mesh products, the MTW Series Trapezium Mill offers robust performance and reliability. Key advantages include:

• Anti-wear blade design reducing maintenance costs
• Curved air duct optimization minimizing energy consumption
• Integrated cone gear transmission achieving 98% efficiency
• Durable grinding chamber construction ensuring continuous operation

With capacities up to 45 tons per hour, this equipment supports large-scale phosphogypsum processing operations for construction material production.

Environmental Considerations and Best Practices

Phosphogypsum processing must address environmental concerns including dust emissions, energy consumption, and potential leaching of impurities. Modern grinding equipment incorporates advanced dust collection systems, energy-efficient designs, and closed-loop water management. Best practices include comprehensive environmental monitoring, regular equipment maintenance, and adherence to industry standards for emissions control.

Economic Analysis and Market Outlook

The economic viability of phosphogypsum utilization depends on processing costs, product market value, and regulatory frameworks. Advanced grinding technologies significantly reduce processing costs while enabling production of higher-value products. Market analysis indicates growing demand for phosphogypsum-based construction materials and soil amendments, creating favorable conditions for investment in modern grinding facilities.

Conclusion

The proper grinding and utilization of phosphogypsum represents a significant opportunity for sustainable industrial development. Advanced grinding technologies, particularly the SCM Ultrafine Mill and MTW Series Trapezium Mill, enable efficient processing of this material into valuable products across multiple industries. As technology continues to advance and environmental regulations evolve, the comprehensive utilization of phosphogypsum will play an increasingly important role in circular economy initiatives and sustainable resource management.