What can you do with fly ash? Revealing the top ten application scenarios of industrial waste
Fly ash is a solid waste produced by coal-fired power plants and has long been viewed as an environmental burden. However, in recent years, with the advancement of environmental protection technology and the popularization of the concept of resource recycling, fly ash has been discovered in a variety of high-value uses. This article will give you a comprehensive analysis of the top ten application areas of fly ash, and attach the latest market data.
1. Basic characteristics of fly ash
The main components of fly ash are SiO₂, Al₂O₃ and Fe₂O₃, which have pozzolanic activity. It can be divided into three grades according to particle fineness and chemical composition:
| grade | Fineness (45μm sieve allowance) | Loss on ignition | Main purpose |
|---|---|---|---|
| Level I | ≤12% | ≤5% | high performance concrete |
| Level II | ≤25% | ≤8% | Ordinary building materials |
| Level III | ≤45% | ≤15% | roadbed filling |
2. Top ten application scenarios of fly ash
1.Building materials field: Fly ash can be used as cement mixture material (20-30% dosage), lightweight block raw material, and ceramsite production material. The latest research shows that the compressive strength of concrete mixed with 35% fly ash can reach 50MPa.
2.road works: When used for roadbed filling, it can increase the CBR value by more than 30%. In 2023, 17 provinces across the country have included fly ash as a standard material for highway construction.
| Project type | Incorporation ratio | Performance improvements | cost savings |
|---|---|---|---|
| highway roadbed | 40-60% | Settlement reduced by 45% | 25-35 yuan/cubic meter |
| Municipal road base | 30-50% | Compressive strength increased by 30% | 18-28 yuan/cubic meter |
3.agricultural improvement: Regulate acidic soil (pH value increased by 0.5-1.2), containing trace elements such as boron and zinc to promote crop growth. It should be noted that the heavy metal content must comply with the GB15618-2018 standard.
4.Environmentally friendly materials: Preparation of sewage treatment agent (COD removal rate ≥ 85%) and flue gas desulfurization agent (SO₂ removal efficiency 92-96%). The 10 new environmental protection projects put into production in 2023 will all use fly ash-based materials.
5.High value-added products: Alumina (ash sample with Al₂O₃ content > 25%) and white carbon black (SiO₂ purity ≥ 90%) can be extracted through deep processing. A company's annual processing of 500,000 tons of fly ash project can achieve an output value of 320 million yuan.
3. Latest industry trends
• From January to October 2023, the comprehensive utilization rate of fly ash nationwide reached 78%, a year-on-year increase of 6 percentage points
• Inner Mongolia has built the world’s largest fly ash extraction alumina production line (annual production capacity of 500,000 tons)
• The newly revised "Measures for the Comprehensive Utilization of Fly Ash" will be implemented in 2024, clarifying the detailed rules for tax incentives
4. Technological breakthroughs and future trends
1. Ultra-fine grinding technology: fly ash can be ground to D50≤3μm, and the activity index can be increased to 110%
2. Carbon capture and utilization: Through mineralization and storage technology, each ton of fly ash can fix about 50kg of CO₂
3. Extraction of rare metals: The recovery rate of strategic metals such as gallium and germanium exceeded 75%
| Technical direction | R&D progress | Economic benefits | environmental benefits |
|---|---|---|---|
| Geopolymers | Laboratory strength reaches 80MPa | 40% lower cost than traditional cement | 60% reduction in carbon emissions |
| Zeolite molecular sieve | Pilot product purity is 99.5% | Value increased 20 times | Improved wastewater treatment capacity |
5. Precautions for use
1. Radioactivity detection: must comply with GB6566-2010 standard (internal exposure index ≤ 1.0, external exposure index ≤ 1.3)
2. Heavy metal control: As, Cd, Pb, etc. content must be lower than the limit of the "Soil Environmental Quality Agricultural Land Standard"
3. Storage requirements: The moisture-proof stacking height should not exceed 10 meters. If the storage period exceeds 3 months, the activity must be re-tested.
With the advancement of the "double carbon" strategy, fly ash is transforming from "industrial waste" into "urban minerals". It is expected that by 2025, the scale of my country's fly ash comprehensive utilization industry will exceed 100 billion yuan, becoming an important growth point of the circular economy.
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