[China Aluminum Network] In order to encourage enterprises to comprehensively develop and utilize high-alumina fly ash resources, since 2011, the National Development and Reform Commission has specifically formulated the "Guidelines for Strengthening the Development and Utilization of High-Al Aluminum Fly Ash Resources." At present, high-alumina fly ash extraction of aluminum oxide multi-generation technology has now been realized industrialization. Promote the healthy development of fly ash extraction in the alumina industry, and use this as the core to build China's strategic layout of high-aluminum coal recycling industry.
Coal, in addition to generating electricity and preparing coal chemical products, is also closely related to our daily products. After the National Key Laboratory of High Alluminium Coal Resources Development and Utilization and Inner Mongolia Datang International Renewable Resources Development Co., Ltd., the shadow of coal may be found on a piece of white office paper and a bag of fresh and clean detergent. All of these products can incorporate chemical fillers extracted from fly ash.
"The high-alumina fly ash extraction of alumina is not only a comprehensive utilization of fly ash in the traditional sense, but it is based on this project to form an industrial chain for recycling all components of fly ash." Sun Junmin, director of the Key Laboratory of Energy High Aluminum Coal Resources Development and Utilization, said.
Alumina extraction has been realized in the industrialization of “high-alumina fly ash extraction of aluminum oxide polygeneration technology, has now achieved industrialization.” Sun Junmin said that Datang Group built in 2008 to deal with 500,000 tons of high-alumina pulverized coal The gray industrialization demonstration project is designed to produce 200,000 tons of alumina annually. The project was put into production in October 2013. Datang International Renewable Resources Development Co., Ltd. has become a high-alumina fly ash extraction alumina company that is commercialized at home and abroad.
According to reports, the project has been operating smoothly since its completion, with an output of 16,700 tons of aluminum oxide per month. Product quality, energy consumption, and material consumption also meet design requirements. At present, the workshop production cost per ton of alumina is basically the same as that produced by sintering.
In order to encourage enterprises to comprehensively develop and utilize high-alumina fly ash resources, since 2011, the National Development and Reform Commission has specifically formulated the "Guidelines for Strengthening the Development and Utilization of High-Al Aluminum Fly Ash Resources." In March of the same year, the National Development and Reform Commission included the high-alumina fly ash comprehensive utilization as an encouragement industry item in the catalog of industrial structure adjustment guidelines.
"The comprehensive utilization of fly ash is not a new thing," Sun Junmin said. In the 1980s, the second session of the National General Meeting on Comprehensive Utilization of Fly Ash, the former deputy director of the State Development Planning Commission, Ye Qing, proposed that fly ash as a building material is still a major conventional use, and the focus of exploration on fly ash utilization should be Extraction of valuable elements such as aluminum.
Since 2003, researchers have discovered that coal fields in the central and western parts of Inner Mongolia and northern Shanxi Province are rich in high-aluminum coal resources. The fly ash produced by this kind of high-alumina coal combustion has an alumina content of 38% to 50% and is of high development value. Afterwards, many domestic enterprises and scientific research institutions were mobilized and engaged in technological development and industrialization exploration. And Datang International can achieve industrialization. Sun Junmin has 3 individuals.
The first one is thanks to a model jointly developed by research institutions and companies. Datang International and Tsinghua University collaborate with each other from the source of technological development and collaborative innovation, and realize the organic integration of process equipment flow, production cost and market. All technical routes are not on paper, but are aimed at industrialization on the cooperation mechanism.
Followed by grounding gas. Based on the relevant experience of the industry, the process technology has carried out a great deal of innovation and improvement on the basis of the original bauxite production alumina technology. From the design to the selection of equipment, the determination of the process route and production management, there is a certain industrial base for reference.
The confidence is firmer later. Since the discovery of high-alumina fly ash, Datang Power has been committed to related technological development and industrial exploration. It has overcome one or two production technical difficulties and has invested more than 8 billion yuan in the direction of the fly ash utilization industry, especially in the current aluminum industry. Under the external environment where the prices of products have dropped sharply and the market is low, the demonstration of coal-fired ash extraction with multi-cogeneration has achieved a series of new breakthroughs in energy conservation, consumption reduction and by-product applications.
From fuel to basic raw materials Coal is a major fossil fuel in China. The large amount of inorganic elements contained in coal is usually treated as ash or harmful substances. Through scientific and technological innovation, the inorganic components in coal can be transformed into various useful products to achieve coal. Conversion from fuel to basic raw materials.
The use of high-alumina fly ash to produce alumina is of great significance for the healthy development and environmental protection of China's aluminum industry. However, Sun Junmin's National Key Laboratory of High-Alluminium Coal Resource Development and Utilization of Energy does not focus on the development of a single project, but instead seeks to utilize all components of fly ash.
For the active calcium silicate produced by the pre-silicon removal process of high-alumina fly ash, R&D personnel have made many innovations in market applications. A more typical example is papermaking.
At present, China produces 100 million tons of paper every year. In the traditional papermaking process, the raw materials contain at least 80% wood pulp, while most of the wood pulp in China is imported from Russia and Canada. The degree of foreign dependence has exceeded 70%, and the price is high. “The porous nature of calcium silicate can be well combined with plant fibers, making it possible to produce high-fill papermaking. At present, the laboratory can add active calcium silicate to 70%, and industrial production line can add 50%, saving per ton of paper. 300 kg wood pulp." Sun Junmin said that the active calcium silicate used in the paper industry is of great significance for energy conservation and emission reduction, but it is still necessary to strengthen industrialization, establish standards, and reduce transportation costs. The combination of plastics production and active calcium silicate has been listed as an important development direction for the “Thirteenth Five-Year Plan”.
"Plastics are heated in the production process and emit volatile organic compounds. The added active calcium silicate can absorb volatile organics and reduce pollution gases from the source. Active calcium silicate can also improve the properties of plastics, improve mechanical strength and resistance to aging. , save resin." Sun Junmin said.
After extracting alumina and active calcium silicate, the rest of the silicon-calcium slag is left behind. In the normal production process, about 2.5 tons of fly ash is required for each ton of alumina extracted, resulting in 2.2 to 2.7 tons of silica-calcium slag. "Because limestone is needed in the sintering process, the extraction of one ton of alumina to produce calcium-silicon-containing slag is basically equivalent to the amount of fly ash used," Sun Junmin said.
Silicon-calcium slag was used to produce cement earlier, but calcium carbide slag was also needed to remove the alkali from the calcium-calcium slag. Although it is technically feasible, the cost is high, the economy is impassable, and how does silicon-calcium slag not be used for alkali removal?
Manufacture of new building materials calcium silicate board, co-use roadbed with fly ash, and replace cement concrete ... ... Each project follows the principle of cost reduction, performance standards and the large-scale consumption of solid waste.
The top-level design is the key national technology development route for key laboratories for energy high-alumina coal resources development and utilization, which has been adjusted from the past comprehensive utilization of fly ash to the current use of fly ash as a carrier to form non-ferrous metallurgy, papermaking plastics, chemicals, and building materials. , roads, ecological restoration and other directions.
To organically integrate more than a dozen industries into a cyclical full-industry chain, Sun Junmin hopes for the local “13th Five-Year” development plan and its effective implementation: “We must follow the state's advocacy of restructuring, transfer methods, and circular economy. The top-level design is highly advanced and the path is planned from the perspective of the industry's entire life cycle."
“The comprehensive utilization of resources must be within the scope of a region and the coordinated use of various resources. This is an important part of the circular economy.” Sun Junmin cited fly ash as an example of ecological restoration and said, “Using fly ash, Silicon-calcium slag, desulphurization gypsum, and municipal sludge, etc., for the improvement of saline-alkaline land and the treatment of desertification, can completely solve the problem of solid waste in Inner Mongolia. Regardless of how it is used, a large amount of solid waste will be returned to China's large-scale coal-fired power plants in northwest China. soil."
Sun Junmin also pointed out that ecological rehabilitation projects cannot be immediate because of their difficulty and lag. “Need to jointly tackle problems with ecological and agricultural scientific research units. After the results have been appraised, we must rely on government coordination, science and technology, environmental protection, agriculture, ecology and other departments combined promotion, and strive to achieve the joint promotion of the strength of the government, enterprises, and capital.”
The industry practice and exploration of comprehensive utilization of environmental protection and resources over the years has increasingly strengthened Sun Junmin’s sense of anxiety over traditional industries. From the perspective of strategic reserve of environmental protection and resources, he suggested that China should implement protective or partially restrictive exploitation of limited precious bauxite resources. The source of alumina should be imported aluminum or high-alumina fly ash.
“Because of the lack of bauxite in China, the destruction of vegetation caused by predatory mining is difficult to recover. On the other hand, in the coal resources of the Junggar Basin, the total amount of potential aluminum oxide in the fly ash generated by combustion is far higher than that already found in China. Bauxite reserves.” The use of high-alumina fly ash to produce alumina not only promotes the healthy development of the aluminum industry but also drives energy saving and emission reduction in the papermaking and building materials industries. Sun Junmin believes that relevant departments should increase tax incentives and support for demonstration projects to promote powder production. The coal ash extracts the healthy development of the alumina industry and builds on this as the core strategically important high-aluminum coal recycling industry in China.
