Recently, 202 1 the second batch of new technologies and new products (services) in Beijing (the sixteenth batch in total) was released, and Zhongjing Environmental Technology Co., Ltd. (hereinafter referred to as "Zhongjing Environment") was certified as a cementing material for flue gas fixed bed desulfurization system of blast furnace hot blast stove, fine desulfurization technology of blast furnace gas, by-products of flue gas treatment and industrial solid waste. The accreditation of new technology and new products (services) in Beijing is an innovative product (service) with advanced technology, clear property rights, reliable quality and broad market prospects, which is selected by the Beijing Municipal Science and Technology Commission, the Beijing Municipal Development and Reform Commission and other departments according to the requirements of the Administrative Measures for Accreditation of New Technology and New Products (Services) issued by the Beijing Municipal Party Committee and Municipal Government, aiming at promoting the application of new technology and new products (services) and promoting the independent innovation of the whole society. MCC Environment has been unanimously recognized by the expert group for its advanced breakthrough technology of preparing cementitious materials from flue gas treatment by-products and industrial solid waste.
With the rapid development of industrial economy, the output of industrial solid waste in China is increasing, and the harm to the environment is increasing. According to statistics, the output of industrial solid waste in China will reach 3.675 billion tons in 2020, 3.8 billion tons in 20021year and more than 4 billion tons in 2022. Therefore, the collection, treatment and resource utilization of industrial solid waste has become a technical problem. With the support of national policies, the comprehensive utilization capacity of bulk solid waste has been significantly improved, and the scale of comprehensive utilization of solid waste has been continuously expanded. Ten departments, including the National Development and Reform Commission, issued the Guiding Opinions on the Tenth Five-Year Plan for the Comprehensive Utilization of Bulk Solid Wastes, proposing that the comprehensive utilization rate of bulk solid wastes will reach 60% by 2025, which means not only encouraging the coordinated utilization of various solid wastes, but also encouraging the coordinated utilization of various industries, and promoting the comprehensive utilization of bulk solid wastes with upstream industries such as coal, electricity, steel, nonferrous metals and chemicals, as well as construction, building materials, municipal administration, transportation and environment.
At the same time, the current production process of portland cement consumes a lot of energy, limestone and clay, and emits about 0.65-0.95 tons of CO2 per kloc-0/ton of portland cement clinker. China's cement output ranks first in the world all the year round, accounting for about 55% of the global output, and its carbon emissions are about 13% of the national annual CO2 emissions, accounting for more than 80% of the carbon emissions of China's building materials industry. Therefore, how to reduce the consumption of energy resources and carbon dioxide emissions in the cement industry is a key factor related to the peak of national carbon dioxide emissions and the success or failure of carbon neutral strategy. In order to reduce the carbon emission in cement production, it is urgent to choose an auxiliary cementing material with low carbon, no secondary pollution (waste residue) and capable of replacing part of portland cement clinker.
2. Preparation of cementitious materials from by-products of flue gas treatment and industrial solid wastes.
In order to reduce CO2 emission and energy consumption in the production process, MCC independently developed a set of solid waste-based colloidal crystal powder cementing materials with independent intellectual property rights.
Crystal powder cementing material is a new cementing material production technology, which can integrate sulfate, nitrate and industrial solid wastes such as red mud, carbide slag, water slag and fly ash formed after desulfurization and denitrification. It is composed of silicon, magnesium, iron, aluminum, sulfur and nitrogen according to a specific ratio and reaction conditions, and it is a high-strength cementitious material. This technology fundamentally breaks through the technical bottleneck of unsustainable, economical and circular treatment of solid wastes such as red mud and carbide slag, which makes the by-products of flue gas treatment and various industrial solid wastes glow with new vitality, realizes the goal of harmless treatment, resource utilization and sustainable output of solid waste resources, and truly realizes "treating waste with waste". This is a brand-new paradigm of environmental governance, which is the perfect integration of advanced technology concepts and advanced productive forces.
Process principle: The preparation process of crystal powder cementitious materials is simple, and non-renewable limestone resources are not used in the production process, which is different from the complex process of "two grinding and one burning" of cement, and the CO2 emission can be reduced by more than 80% without high-temperature calcination of coal, and the raw materials and production process meet the low-carbon goal. The strength index can reach 80- 100 MPa (28d), and the highest can be stabilized at 100 MPa. According to the subsequent use scenarios, not only products with standard ordinary portland cement label can be produced, but also products with specific demand strength of 5-40 MPa can be produced. Based on corresponding substances such as silicon, iron, aluminum, calcium, etc. Under specific proportions and reaction conditions, the molecular substances in large-scale industrial solid wastes release soluble active substances, and then depolymerize and polycondensation to form a special network structure, which further hardens into a cementitious material with "early strength and rapid hardening" properties.
Three, the main innovation achievements of crystal powder cementing material technology
After years of painstaking research and development, the research and development team of Zhongjing Environment has repeatedly polished and developed crystalline powder cementitious materials in the laboratory and mass production, and combined the by-products of flue gas treatment with industrial solid waste, forming a series of innovative achievements, thus completing the integrated and collaborative treatment of flue gas, wastewater and solid waste.
1. Non-calcined low-carbon technology
The crystalline powder cementitious material pioneered in mesomorphic environment mainly takes industrial solid wastes such as fly ash, steel slag, carbide slag, water slag and tailings as raw materials. Its preparation process is simple, and limestone resources are not used in the production process, which optimizes the "two grinding and one burning" process of cement, reduces the high-temperature calcination link of coal combustion, effectively reduces CO2 emission and energy consumption, and greatly promotes the application of low-carbon technology in the fields of cement and building materials.
2. Early strength, fast hardening and good mechanical properties.
Crystal powder cementitious material has the characteristics of fast setting and hardening speed and high early strength. The crystal powder material prepared by the improved process can be solidified quickly and hardened in about 3 hours. The early strength is high, and the compressive strength of 1-3 days can reach more than 80%, which has the characteristics of fast hardening cement; Can meet the construction of various emergency and emergency repair projects.
3. Good durability and thermal stability
Because of the stable network structure, crystal powder can completely avoid alkali-aggregate reaction caused by metal ion migration and aggregate reaction of other cementing materials, and has strong natural damage resistance, good corrosion resistance, low permeability and freeze-thaw cycle resistance. At the same time, the crystal powder also has good thermal stability, which is an oxide network structure system, and does not oxidize or decompose between 1000-1200. The fire resistance limit can reach 1000, and it has good fire resistance, which can completely meet the requirements of fire prevention and flame retardant.
4. Wide sources of raw materials
The raw materials for preparing crystalline powder are all bulk industrial solid wastes, such as fly ash, slag, red mud and construction waste. These solid wastes have a great growth every year, and the storage capacity is very large. In actual production, the main local solid waste can be used as the main raw material, supplemented by other kinds of solid waste around.
5. No secondary solid waste is generated.
Different from purifying valuable elements from single solid waste or preparing other materials by modification, crystalline powder cementitious materials can produce products with corresponding quality according to different grades of solid waste; Match high, medium and low quality products. Under the premise of not making major adjustments to the process, the solid waste is utilized to the maximum extent to make it resource-oriented, productized and commercialized. Externally, there will be no secondary solid waste such as residue, and the solid waste will be "eaten dry and squeezed out".
Fourth, the application and effect
Crystal powder cementitious materials can be used in various engineering scenes, such as preparing crystal powder-based concrete, fair-faced concrete, producing assembled wallboard, prefabricated components and so on. MCC has developed a series of products with strong practicability and high value, such as crystal bricks and crystal plates, which can be used for commercial and civil buildings and decoration, and can also be used for backfilling various mines (pits). Combined with other solid wastes used for conditioning, fillers meeting backfill requirements can be obtained. This technology has obtained 16 invention patents and 2 utility model patents, and won the first prize of circular economy patent in China and the third prize of scientific and technological progress in Beijing.
1. crystal bricks, crystal plates and other series of practical high-value products.
Building materials, such as crystal bricks and crystal plates, which are made of crystal powder cementing materials, have been tested by the National Building Materials Quality Inspection Center, and their strength is high, density is low, and the fire resistance rating reaches A 1. It also has the advantages of low thermal conductivity, good thermal insulation and low water absorption. Compared with other similar building materials products in the market, it has a strong competitive advantage in cost and performance, the cost is lower than that of cement products by more than 30%, and the compressive and flexural properties are higher than that of cement products by more than 50%.
2. Mine restoration
Mesomorphic solid waste technology can use stripped topsoil, rock fragments, low-grade ore and tailings produced after concentrate separation left by ore mining as raw materials, supplemented by other common bulk industrial solid wastes, take local materials, adapt measures to local conditions, turn waste into treasure, and produce solid waste-based cementitious materials "crystal powder". The crystalline powder cementitious material can replace the traditional cement without high-temperature calcination, and can be directly used for mine restoration and transformation, and can also be used as products in infrastructure, building materials and other fields. The application of crystal powder cementing material technology meets the requirements of China's "double carbon" policy and can make due contributions to the realization of zero carbon governance and even negative carbon governance.
3. Mine backfill
Crystal powder cementitious materials can also be effectively used in various mine backfill processes. Taking underground mining mines as an example, a small amount of conventional "crystal powder" can be used to replace the traditional clinker-based cementing agent, and mining tailings can be mixed to form a filling body for backfilling; According to the production principle of "crystal powder", tailings can be directly used as the basic raw material, supplemented by ordinary industrial solid waste, and the filling body that meets the requirements can be produced on site. Filling a large number of tailings into the ground can reduce the pollution caused by tailings discharge and other wastes, play a good supporting role in underground mined-out areas, avoid the collapse of surrounding rocks in mined-out areas, and prevent the destruction of ecological environment by a large number of mined-out areas, thus effectively protecting the surface of mining areas. Crystal powder technology and its application in mesomorphic environment can replace clinker-based filling materials, effectively reduce filling costs and improve the enthusiasm of solid waste filling mines.
Verb (abbreviation of verb) conclusion
Driven by the national "double carbon" strategy, non-calcined low-carbon cementing material with industrial solid waste as the main component has become a new choice to replace ordinary portland cement, and it is believed that this technology will become the first choice for the cement industry to realize the "double carbon" strategy.