1. Introduction
Fly ash is one kind of fine particle waste produced after the combustion of coal powder in coal-fired power plants. Its global annual emissions exceed 700 million tons. The chemical composition of fly ash is mainly SiO₂ (40-60%), and Al₂O₃ (20-35%), with a small amount of Fe₂O₃, CaO and unburned carbon. Traditional stacking method not only occupies a large amount of land, but also causes the risk of heavy metal pollution. Realizing high-value utilization through powder processing technologies has emerged as a critical path in circular economy development.
2. Processing technology and equipment
2. Processing technology and equipment
① Pretreatment
Magnetic separation and iron removal: By using 0.1-0.3T permanent magnetic drum, the iron impurity content can be reduced from 1.5% to 0.05%.
② Ultra-fine grinding technology
Vertical roller mill: 30% less energy consumption than ball mill, with a specific surface area of 500m²/g.
Jet milling system: By combining a turbine classifier to achieve D50: 2-5μm, and used for lithium battery diaphragm coating.
For jet milling + classification, you can use jet mill + HTS air classifier production line produced by Qingdao Epic Powder Machinery Co., Ltd. The combination of the two for grinding and classifying fly ash is an efficient and fine powder processing solution, especially suitable for occasions that require ultra-fine powder and precise particle size distribution. Our air classifier includes 5 types: HTS, ITC, CTC, MBS, and TDC. If you have relevant needs for jet mill or air classifier or other powder processing equipment, please contact our staff directly.
③ Deep decarburization process
Microbial decarbonization: After 72h of pseudomonas treatment, the carbon content dropped from 8% to 0.5%.
Microwave calcination: 500℃ treatment for 30 minutes, energy consumption is reduced by 40% compared with traditional calcination.
④ Surface modification technology
Silane coupling agent treatment: The activation index is increased from 60% to 95%, enhancing compatibility with resin.
For surface modification of fly ash, the continuous surface coating equipment produced by Qingdao Epic Powder Machinery Co., Ltd. can be used: pin-mill modifier, three-rotor-mill modifier and turbo-mill modifier. They are with high modification rate and long-lasting modification effect.
Nano-SiO₂coating: Enhanced dispersibility for thickening high-end coatings.
3. Diversified application areas
Application | Technical indicators | Typical products | Performance advantages |
| Green building materials | 45μm sieve residue ≤12% | High performance concrete admixture | 20% increase in strength and 30% reduction in shrinkage after 28 days |
| Environmental engineering | Heavy metal curing rate＞90%, specific surface area300m²/g | Soil conditioner | Stabilizes pH at 7.5-8.5, repairs acidic soils |
| New energy materials | Energy density 20Wh/kg (50% higher than activated carbon) | Supercapacitor electrodes | Capacity up to 250F/g, cycle life 5000 times |
| High-end ceramics | Al₂O₃≥55% | Mullite precursor | 40%The calcination temperature is reduced by 150℃, and the bending strength is increased by 40% |
4. Conclusion
industrial solid waste. Through innovation in powder processing technology, its application has extended from traditional building materials to new energy, high-end manufacturing, etc. In the future, with the deep integration of nanotechnology, bioengineering and intelligence, fly ash is expected to become an important resource to support strategic emerging industries.
