What is the introduction review of the current status of comprehensive utilization of fly ash?

Fly ash is one of the most accumulated solid wastes in China. The accumulation and discharge of fly ash not only occupy a large amount of land resources, but also easily cause environmental pollution. Fly ash contains a certain amount of useful components and valuable elements such as residual carbon, magnetic beads and microbeads. Upgrading or comprehensively utilizing fly ash according to its characteristics is of great significance to reducing environmental pollution and improving the economic benefits of fly ash. As a fly ash vertical mill manufacturer, Guikuang Machinery will introduce a review of the current status of comprehensive utilization of fly ash.

Comprehensive utilization methods of fly ash:

1. Application in construction engineering and building materials industry

In construction projects, fly ash can be used as backfill material for roads and civil engineering projects, and can also be used as cement raw material and mixture instead of clay. In terms of building materials, it can be used to produce fly ash cement, sintered fly ash bricks, fly ash ceramsite, fly ash tiles, fly ash sheets, aerated concrete, foam glass, geopolymer cementitious materials, etc.

2. Application in road engineering

Fly ash can be used as road base and sub-base materials, embankments, pavement repair and backfill materials, and grouting materials. Studies have shown that using decarburized fly ash concrete to repair pavement, the pavement strength is close to that of pavement without fly ash, which is in line with national pavement engineering standards.

3. Application in agriculture

Fly ash has physical properties such as porous, light weight, and fine particles, which can improve soil texture and soil structure, and increase soil water storage capacity and light transmittance. At the same time, fly ash contains magnesium, calcium, potassium, phosphorus, and trace elements such as copper, boron, zinc, and manganese. When applied to farmland, it can improve soil fertility and promote the growth of crops. For example, silicon fertilizers, compound fertilizers and fly ash magnetic fertilizers produced using fly ash have significant yield-increasing effects. The application of fly ash in agriculture has the advantages of large dosage, significant effect, and low initial investment.

4. Application in environmental protection

Fly ash has high adsorption activity and can be used to purify wastewater. It has a good removal effect on COD and chroma. In addition, fly ash contains alkaline substances such as CaO, which can be used as a desulfurizer for coal combustion flue gas. The silicon, aluminum, iron and other oxides in fly ash are deoxidized at high temperature and used to smelt silicon-aluminum alloys or sort hollow glass beads. Silicon-aluminum alloys can be produced by adding reducing agents to smelt under specific conditions. Fly ash contains a large amount of glass microspheres, the main chemical components of which are silicon, aluminum, and iron oxides. It has excellent properties such as hollow, small particles, heat insulation, sound insulation, acid and alkali resistance, high strength, and good insulation. It is used as a filler in advanced spray materials and fireproof materials, and as a cracking catalyst in the petroleum refining process with good results.

5. Extraction of alumina

China is a major aluminum producer and consumes a large amount of bauxite resources every year. The limited and non-renewable nature of bauxite resources makes the comprehensive utilization of aluminum-rich fly ash of great significance. The alumina content of fly ash is between 17% and 50%. Extracting alumina from fly ash has attracted attention from all walks of life.

6. Produce molecular sieves and use them as reinforcing fillers in rubber

Various molecular sieves can be produced by using fly ash as raw material through hydrothermal synthesis, hydrothermal conversion and ion exchange. In addition, surface modification of fly ash through coupling agents, etc. can be used as rubber reinforcing agent.

7. Manufacturing foam glass

Foam glass is an inorganic non-metallic glass material with moisture-proof, anti-corrosion, fire-proof and non-toxic properties. It is widely used in construction and decoration materials. Fly ash is mixed into the foam glass batch, and then a foaming agent is added to the green body to make a lightweight glass body with a pore structure under certain conditions. Fly ash foam glass has the characteristics of low thermal conductivity, low density, not easy to weather and age, high strength, sound absorption, moisture-proof, etc. It can be used as waterproof, thermal insulation, heat insulation, sound insulation materials, as well as concrete aggregate and filling materials.

The above is a summary of the current status of comprehensive utilization of fly ash. At present, the comprehensive utilization of fly ash is mainly reflected in building materials, such as used in the production of cement, used as commercial concrete additives, used in the production of aerated concrete, lightweight blocks, etc. Although the building materials field is a large-scale utilization channel for fly ash, the utilization level is low. However, the development of high value-added utilization of fly ash, such as the production of silicon-aluminum alloys, alumina, etc., has been relatively slow. As an industrial waste, fly ash has a very wide range of applications in the field of building materials. In the application of preparing multifunctional materials, it has a high added energy value, can improve the resource utilization rate of fly ash, and take into account both environmental and economic benefits. The Guikuang series fly ash vertical mill produced by Guikuang, as an efficient and energy-saving cement mill equipment, plays an important role in fly ash grinding.

The working principle of vertical mill is suitable for grinding fly ash. The fly ash is pulverized by rotating grinding discs to the required fineness. The vertical mill has a high-speed rotating grinding disc and strong centrifugal force, which can effectively refine and grind fly ash to a smaller particle size. This efficient grinding process can not only improve the activity of fly ash, but also increase its application value in cement, concrete and other fields. The application of vertical mills in fly ash grinding not only enables waste reuse, but also has a series of advantages. First of all, the vertical mill has high grinding efficiency and can quickly grind fly ash into the required particle size. Secondly, the vertical mill has a low energy consumption level and adopts energy-saving control technology, which effectively reduces energy consumption. In addition, the vertical mill can also adapt to different fly ash quality and production needs, and achieve precise grinding effects by adjusting the grinding disc structure and grinding parameters.

In the future, as the demand for fly ash reuse continues to increase, the application of vertical mills in fly ash grinding will be further expanded. Through technological innovation and process improvement, vertical mills will better meet the requirements for fly ash grinding and provide higher quality, more sustainable fly ash products. At the same time, as environmental regulations continue to strengthen, vertical mills will also focus on reducing dust and exhaust emissions to better adapt to environmental protection requirements.