Basalt is commonly used as a paving material in China. However, after special treatment, it can transform into a high-performance fiber material with a metallic sheen—basalt fiber. This fiber is 5 to 10 times stronger than steel, yet its weight is about one-third that of steel of the same volume, greatly enhancing its application value. Thus, the technology for producing basalt fiber is often referred to as "turning stone into gold."
High-quality development relies on robust support from new materials. During the 13th Five-Year Plan period, basalt fiber was listed as one of the state's four critical fiber materials for development. The "Guiding Directory for the First Batch of Key New Materials Application Demonstration (2019 Edition)" implemented at the beginning of this year also listed basalt fiber as a critical strategic material.
In recent years, China's basalt fiber manufacturing technology has accelerated, achieving many breakthroughs and supporting emerging industries such as new infrastructure and intelligent manufacturing.
From Common Paving Stone to High-Tech Fiber Material
Anyone who watches martial arts dramas will remember a magical armor made from "golden threads," which is lightweight and impervious to swords and spears. Today, researchers have indeed created such mystical armor. These modern armors are solid and lightweight and endowed with powerful functions.
For example, firefighters can charge into blazing infernos wearing heat-resistant and high-temperature-tolerant armor. Astronauts can roam space with armor that shields them from radiation. Ships navigating the seas have armor that is both flexible and corrosion-resistant. Bridges connecting the north and south are built with sturdy, wear-resistant, and lightweight armor.
Traditional metal materials can no longer meet these demanding requirements, but a high-tech fiber material—basalt fiber—can.
When basalt rock is crushed into powder and melted in a furnace at temperatures over 1200°C, it becomes liquid. After clarification, cooling, and homogenization, the liquid is extruded through a leak plate and drawn by a high-speed drawing machine into fibers resembling cotton candy, measuring 7 to 20 microns in diameter. This is basalt fiber.
Despite its diameter being only one-third that of a human hair, basalt fiber is twice as strong as steel fibers of the same diameter. It is more corrosion-resistant than alloys and can withstand temperatures up to 500°C. Twisted basalt fibers resemble cotton threads and can be woven into cloth for protective clothing. Basalt fiber reinforced composites, made by combining basalt fibers with polymer matrices through specific processes, have high strength-to-weight ratios and can manufacture the shells of tanks, ships, and airplanes. Furthermore, basalt is a natural mineral, and the production process of basalt fiber emits minimal harmful substances, resulting in little environmental pollution.
Basalt fiber has many applications in aerospace, construction, building materials, road and bridge construction, shipbuilding, wind power generation, and more.
Hou Jinlong, Deputy Director of the Expert Committee of the China Highway Society, explains, "Road-use basalt fiber can effectively reduce road cracking and rutting, significantly extending the service life of the pavement and improving the high-temperature stability and low-temperature crack resistance of road structures."
At the end of 2018, the famous Nanjing Yangtze River Bridge reopened after closed repairs. The upgraded bridge utilized basalt fiber in critical areas. Basalt fiber has excellent tensile reinforcement properties. The bridge construction team bonded basalt fiber to concrete components to reinforce the bridge, making it lighter and more durable. Additionally, basalt fiber has been used in projects such as the Hangjinqu Expressway, the Zhengwan High-speed Railway, and the construction of islands and reefs in the South China Sea.
"Basalt fiber technology has only been around for 30 years, and its application is still in the early stages globally," says Liu Jiaqi, a researcher at the Institute of Geology and Geophysics, Chinese Academy of Sciences. "Currently, the world's basalt fiber production cannot even meet 1% of the demand." China has abundant basalt resources, with large deposits in Gansu, Heilongjiang, Xinjiang, Shanxi, Sichuan, and other regions. If these stones, mainly used for paving, are fully utilized and transformed into fiber materials, it will significantly boost the new materials industry.
Overcoming Numerous Challenges to Make Stone "Obedient"
Turning hard rock into fibers is no easy feat, especially when dealing with a type of stone that is not so "obedient."
Ma Pengcheng, a researcher at the Xinjiang Institute of Physical and Chemical Technology of the Chinese Academy of Sciences, has been devoted to basalt fiber research for many years. He told reporters, "Firstly, basalt ore is a natural product with significant fluctuations in chemical composition. Therefore, the properties of basalt fiber are inherently unstable during preparation. Secondly, the process from basalt ore to basalt fiber involves melting and fiber forming. During the basalt melting process, various minerals in the ore gradually melt. If incompletely melted crystalline phases are present, secondary crystallization nuclei can easily form. The basalt melt exhibits varying crystallization tendencies in the basalt fiber forming process. Such crystallization needs to be minimized; otherwise, it will affect the fiber's characteristics and the quality of the final product."
Proudly, China is one of the few countries worldwide that has mastered the technology for basalt fiber production. Ma Pengcheng stated, "Although China's research on basalt fiber started relatively late, through continuous and arduous exploration, researchers and relevant enterprises have overcome many technological challenges, achieved mass production of basalt fiber, and formed a certain market scale."
The technology of basalt melting and drawing in a fully electric melting pool kiln is an independent innovation in China. On June 22nd, the world's first set of basalt continuous fiber production lines with a capacity of ten thousand tons, with complete independent intellectual property rights, was officially implemented. On July 1st, the intelligent leaking plate drawing pool kiln production line for 2400 holes of basalt fiber was ignited and put into operation.
"The completely self-designed melting kiln is the core equipment of the entire production line," said Li Jun. "The so-called 'full electric melting pool kiln' means that the kiln uses electric energy as the sole energy source during the process of mineral melting. Internal heating achieves rock melting by placing electrodes inside the basalt melt."
To address the instability of basalt during the melting process, researchers from relevant enterprises conducted extensive research on basalt fiber pool kiln drawing technology. After countless failures and attempts, they conquered dozens of problems. For example, to stabilize basalt during manufacturing, researchers selected raw materials through big data optimization at the ore selection stage to ensure higher ore grade. In the crushing and raw material preparation stage, they used globally innovative technologies such as air-powered crushing and homogenization to enhance the stability of raw material mineral components. They solved the problem of low melting capacity and poor uniformity of basalt mineral raw materials in the melting stage by designing large-unit pool kilns. They also addressed the high melting temperature of basalt by combining pure oxygen combustion with electric melting assistance.
To reduce the cost of basalt drawing and improve the quality of fiber filaments, researchers focused on the critical equipment—the leaking plate—where the solution turns into filaments. They aimed to achieve multiple leaking plates in one drawing process and to increase the number of holes in each leaking plate as much as possible.
"New materials have only emerged in recent years, and we do not have many mature foreign technologies to introduce, so we are destined to innovate independently. Through scientific means, we allow a low-value product like basalt to unleash its vitality. This is the ideal and mission of us researchers," said Ma Pengcheng.
China's new material technology innovations have entered a "no-man's land."
Materials are the basis of manufacturing and shape the muscles and bones of a large country.
Part of China's new material technology innovation has entered a "no-man's land," according to Academician Gan Yong of the Chinese Academy of Engineering. Represented by new-generation information technology, new energy, intelligent manufacturing, and other emerging industries, the demands on materials have become unprecedentedly high, with increasing difficulties in research and innovation. It can be said that some of China's new material technology innovations have entered a "no-man's land."
Regarding basalt fiber, the next step for researchers and manufacturers is to address how to enhance its performance and make it more affordable through technological innovation. In the mineral-rich region of Xinjiang, the Xinjiang Institute of Physical and Chemical Technology of the Chinese Academy of Sciences (hereinafter referred to as Xinjiang Institute) has established an extensive database of Chinese basalt fiber materials based on domestic geographical and geological factors. This database facilitates data sharing and big data analysis in the field of basalt fiber, which can guide the fiber drawing process and provide technical feasibility for developing high-performance basalt fiber materials.
Xing Dan, a research assistant at the Xinjiang Institute, explained that in the past, basalt fiber was considered an insulating material because it was non-conductive. However, in recent years, researchers have used the metallic elements inherent in basalt fiber to achieve controlled growth of carbon nanomaterials on the fiber's surface, resulting in conductive fiber materials. This has overturned the traditional concept that basalt fiber is an insulator and has increased the functional value of basalt fiber, expanding its applications in areas such as electromagnetic shielding.
Simultaneously, with the advancement of China's lunar exploration project, researchers have explored the feasibility of using basaltic regoliths distributed on the lunar surface to produce continuous fibers. Research shows that lunar regolith has a chemical composition, mineral composition, and fibrous behavior similar to terrestrial basaltic ores.
Not only basalt fiber but also recent data shows China's new material innovation system is increasingly perfect. Manufacturing innovation centers, technology innovation centers, national key laboratories, and industrial bases have reached about 400, and related innovative achievements continue to emerge.
Research teams from Southwest Jiaotong University and others developed a high-strength flame-retardant glass fiber composite material in May this year. This material can be applied in rail transportation. By "wearing" the new material "armor" of high-strength flame-retardant glass fiber on the track power supply and emergency facilities, the performance indicators such as strength, flame retardancy, corrosion resistance, insulation, thermal conductivity, and water resistance of the track can be significantly improved.
Ma Pengcheng stated that new materials are not necessarily entirely new substances; innovatively transforming traditional materials through scientific means is also a form of new material. With the advancement of new material research, in the future, not only stones but also everyday items such as plants, metals, etc., can undergo magnificent transformations, bringing us a different and novel experience in life.
Academician and Vice President of the Chinese Academy of Engineering Gan Yong: New material technology is foundational.
Reporter: General Secretary Xi Jinping pointed out during his inspection in Shanxi that the new material industry is a strategic and foundational industry and a key area of high-tech competition. He emphasized the need for us to catch up and keep pace. Why is the new material industry considered strategic and foundational?
Gan Yong: Everything is composed of matter, and one step further in the development of matter leads to materials. Our lives are inseparable from materials, and the development of our real economy and technology is equally reliant on materials. The material industry is the material foundation of national economic construction, social progress, and national defense security. Especially now, the cross-integration of industrialization with information technology has accelerated the entire process of industrialization. It can be said that humanity has entered a new era. To accelerate development in this new era, it is essential to value the role of materials. Because the development of technology is primarily based on the development of materials. After the development of new-generation materials, it can drive the development of new-generation technologies, new-generation equipment and machinery, and new-generation projects. For example, after the emergence of superconducting materials, we can produce a series of high-end medical devices; after the effective utilization of new-generation semiconductor materials, further development in areas such as 5G communication becomes possible. Therefore, the new material industry is strategic and foundational.
There are two types of new materials: one is the discovery of materials with new uses and functionalities, and the other is the upgrading of traditional materials to give them new properties. Currently, China ranks among the world leaders in the production of over a hundred types of materials, including steel, non-ferrous metals, rare earth metals, cement, glass, and chemical fibers. After these traditional basic materials are prepared using advanced technologies, they can be transformed into new materials, which can then be used to produce devices, modules, and other products needed for various engineering projects. It is this transformation of material properties that gives rise to new industries, new equipment, and new national strength. Just as our bodies need bones and muscles to grow, new material technology is a foundational technology.
More importantly, new materials also play a leading and guiding role. The emergence and development of advanced industries, advanced equipment, and high-end equipment all require materials that can meet their advanced functionalities. Therefore, once the performance of materials is improved, other industries will develop correspondingly. Materials should take the lead. It is precisely because of its guiding role that it has strategic importance.
In the past, when we researched and manufactured high-performance aircraft, sometimes we developed the aircraft first and then tried to develop supporting materials. However, we often found that it was too late because the development cycle of materials is longer than that of technology. If the specific materials for the overall design of the aircraft are suitable, the quality level of the aircraft will improve.
Reporter: What achievements or advantages has our country achieved in developing new materials? What areas still need urgent improvement?
Gan Yong: Our country has established a relatively complete material system, and we have almost all the essential materials needed for the national economy. However, we still need to improve in terms of new materials, especially many high-end materials, including critical composite materials, new energy materials, semiconductor materials, rare earth functional materials, information display materials, and biomedical materials. But it is gratifying that our country is also striving to catch up in the field of new materials. For example, the development of carbon fiber and graphene has been very rapid, and the popularization and application of our super steel are also progressing well.
In addition, the gap between our country and some developed countries regarding new materials lies in improving material performance. The development of modern economic society requires increasingly sophisticated industrial equipment, which in turn requires materials that are ultra-pure, high-strength, and possess special properties while also demanding low material costs. Especially in strategic industries such as aerospace, the materials needed will not be sold to us by foreign countries; they will only sell us finished equipment like aircraft. Therefore, we will be disadvantaged if we do not have the production capacity.
Therefore, China must make significant efforts to develop critical strategic materials to strengthen its independent innovation capabilities. Because many new materials and their production technologies are invented abroad, foreign countries also set many standards in the field of new materials. We need our technology to have a say in new materials.
Reporter: Some people believe that the next five years will be crucial for China's new materials development to transition from being significant to strong. What is your opinion on this?
Gan Yong: Why do some people say that the next five years are crucial for developing China's new materials industry from being significant to strong? In my personal opinion, this year marks the end of the "13th Five-Year Plan" and the decisive year for the comprehensive construction of a moderately prosperous society. As we enter the "14th Five-Year Plan" period, we are entering the fourth industrial revolution in the world. The fourth industrial revolution is characterized by breakthrough technologies such as graphene, genetics, virtual reality, and quantum information technology. China missed out on the first three industrial revolutions. Therefore, this time, we must stay caught up.
As I mentioned earlier, materials are the foundation. Therefore, breakthroughs must first occur in materials for our other high-tech industries to grow and strengthen. In the next 10 to 15 years, China's development of the new materials industry must enter the ranks of international excellence and achieve a transition from a significant materials producer to a strong materials nation. Only then can we genuinely promote concepts like being a manufacturing powerhouse because strong materials are necessary for other industries to become truly strong, and ultimately, we will still be subject to others' control? If we do not break through in materials, we will be left behind again in the wave of the fourth industrial revolution.
Furthermore, we have the conditions to transition from being a significant materials producer to a strong materials nation. For example, we have a large number of researchers in the field of materials. The development of materials is characterized by long cycles, especially when researching a new material. It takes a long time and requires significant investment, and there may be no immediate applications. Fortunately, our researchers are not afraid of hardship. We have an abundant talent pool of researchers. We have over 150 universities in the country with materials-related disciplines, over 200 academicians from the two academies in new materials, and more than 60 national critical laboratories for new materials. This complete system has become the backbone for comprehensively promoting the development of our latest materials industry. Additionally, we have a vast domestic materials market with high demand. Economic growth will drive the development of numerous technologies, thereby supporting our research in new materials. For example, as we adjust our energy structure and reform coal-fired technologies, we require tens of millions of heat-resistant alloys and steels. Furthermore, as we engage in deep-sea mining, we need various corrosion-resistant alloys and seawater desalination membrane materials.
In about five years, we can achieve a basic level of security in the field of materials; in about ten years, we can become strong in some areas. At present, we must seize the time and make sure to keep up. If we don't, we will be left behind.
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