Alumina extraction has achieved industrialization of high-alumina fly ash has been gorgeous turned

In order to encourage enterprises to comprehensive development and utilization of high aluminum ash resources, since 2011, the National Development and Reform Commission specifically formulated the "Guiding Opinions on Strengthening high aluminum ash resources development and utilization." Currently, high aluminum ash extract alumina multi-generation technology, we have achieved industrialization. Promote the healthy development of fly ash extraction alumina industry, and use this as the core to build China's strategic allocation 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.

"High aluminum ash extract alumina co-production of fly ash utilization projects not only in the traditional sense, but rather to the project based on the formation of fly ash recycling component of the whole industry chain." State Sun Junmin, director of the Key Laboratory of Energy High Aluminum Coal Resources Development and Utilization, said.

　 Alumina extraction has been industrialized

"High aluminum ash extract alumina multi-generation technology, has achieved industrialization." Sun Junmin said, Datang Group, the construction of industrialization demonstration project, dealing with 500,000 tons of aluminum powder coal ash high in 2008, Designed to produce 200,000 tons of alumina annually . The project in October 2013 of production, Datang International Renewable Resources Development Co., Ltd. to become the only domestic and foreign high aluminum ash extract alumina commercial operation of the enterprise.

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 the sintering process .

In order to encourage enterprises to comprehensive development and utilization of high aluminum ash resources, since 2011, the National Development and Reform Commission specifically formulated the "Guiding Opinions on Strengthening high aluminum ash resources development and utilization." In March, the National Development and Reform Commission in the Guiding Catalog of Industrial Structure Adjustment, the comprehensive utilization of coal ash again high aluminum industries encouraged by the inclusion of entries.

"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 large part of 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 regions 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 is a model that benefits from the joint development of 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 equipment selection, process route determination and production management, there are certain industrial foundations for reference.

Finally, there is confidence. Has found that high aluminum from coal ash, Datang International has been committed to technology development and related industries to explore, overcome difficulties one after another production technology, the total investment in the industrial utilization of fly ash direction of more than 8 billion yuan, especially in the current aluminum 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 the most important 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 converted into various useful products to achieve the goal from coal to fuel. The conversion.

The use of high aluminum fly ash production of alumina, aluminum and healthy development of China's environmental protection is of great significance. 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 high aluminum ash pre-desilication output active calcium silicate, researchers will be many innovations in its market applications, the most typical example is paper.

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 foreign dependence has exceeded 70%, and the price is high. “The porous nature of calcium silicate can be combined well with plant fibers to make high-fill papermaking possible. Currently, the laboratory can add active calcium silicate to 70%, and industrial production lines 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 adsorb 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 silicon-calcium slag is almost the same as the use of fly ash," Sun Junmin said.

Silicon-calcium slag was first used for the production of cement, but it is also necessary to use calcium carbide slag to remove alkali from the calcium-calcium slag. Although it is technically feasible, the cost is high and the economy is impassable. How can calcium-silica slag be used without alkali removal?

Manufacture of new building materials calcium silicate board, co-use roadbed with fly ash, replace cement concrete... Each project follows the principle of cost reduction, performance compliance, and large-scale consumption of solid waste.

　 Top-level design is the key

The technological development route of the national key laboratory for high-alumina coal resources development and utilization 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, building materials, roads, and ecology. Repair multiple 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 structure, transfer methods, and circular economy. Design the top level highly and plan the path from the perspective of the entire life cycle of the industry."

“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 for the ecological restoration project. “Using fly ash, Silicon-calcium slag, desulphurization gypsum, and municipal sludge are used for salt and alkali improvement and desertification treatment. It is possible to completely solve the problem of solid waste in Inner Mongolia. No matter how it is used, a large amount of solid waste will eventually return to the soil for large-scale coal and electricity bases in northwest China. ."

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 environmental protection of strategic reserves and resources, he suggested, our response to the limited valuable bauxite resources to implement protective or partial restriction mining, alumina source of raw materials should be imported bauxite and high aluminum powder coal ash based.

“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 greater than that in China. bauxite reserves. "ash production and use of high aluminum alumina, aluminum not only promote the healthy development and promote the paper, building materials industry, energy conservation, Sun Junmin think authorities should increase tax incentives and demonstration projects to support efforts to promote powder The coal ash extracts the healthy development of the alumina industry and builds on this as a core strategically important high-aluminum coal recycling industry in China.

Source: Science and Technology Daily