Basalt fibers are formed from molten, stretched basalt rocks. Basalt is an omnipresent natural resource that covers almost a third of the earth's surface, including a large portion of the ocean floor. Many natural landscapes that have become popular tourist destinations are also made of basalt, such as the giant dike in Ireland and the "Devil's Rock Pillar" in California.
To turn the rocks into fibers, the basalt melting furnace is heated to about 1500 ° C (200 ° C higher than similar glass fiber melting furnaces) so that the rocks are drawn through a platinum-rhodium alloy drain plate after melting. As the fibers leave the furnace, they are treated with sizing agents, making them useful for downstream applications or in combination with resins. The chemical composition and effect of basalt fiber infiltrants are very similar to glass fibers.
As a continuous fiber, basalt fibers can be chopped, ground, twisted, woven, knitted, or otherwise processed. Its diameter is usually 13 or 17 microns (μm), but can range from 9 to 21 microns. The standard linear density range of the fiber is 68 to 4800 tex.
Compared with glass fiber and carbon fiber, basalt fiber is in the middle of the market in terms of price and performance. Compared with glass fiber, it has significant mechanical performance advantages, its stiffness and strength are higher than glass fiber; and for applications that require higher performance, its cost is much lower than carbon fiber.
The performance characteristics and market penetration potential of basalt fibers appear to be very attractive. But the question is: when will basalt fiber composites get significant market promotion?
According to James Streetman, manager of Advanced Filament Technologies, there is a joke in the industry that the application of basalt fiber reinforced plastics (BFRP) "has been 5 years away from major breakthroughs in the past 15 years." Advanced Fibers The technology company now supplies basalt fiber called Sudaglass. This fiber was originally produced in Russia's Sudogda and is now produced by China's ZJJS Basalt Fiber Technology Co., Ltd. Aside from this joke, cautious optimism may best represent the mood of Streetman-more broadly, the mood of many BFRP stakeholders. Nick Gencarelle, head of American Intelligent Building Systems, described the development of the BFRP market as "very slow and flat," but he also said that things have started to improve in the past two years. Structural engineers are beginning to understand more fully the need for BFRP.
As a result, basalt fiber manufacturers continue to unswervingly capture this market and are addressing technical issues that have so far failed to achieve breakthroughs. Although the market growth of basalt fiber composites is still largely to the future, basalt fiber manufacturers are making progress in these areas and are approaching large-scale applications.
A report published by India's MarketsandMarkets in June 2015 estimated that the recent overall growth of the basalt fiber market, including composite and non-composite uses, is considerable. According to the report, the global basalt fiber market will reach US $ 200 million in 2020, with a compound annual growth rate (CAGR) of 13.1% from 2015 to 2020. "We are updating our existing research on the basalt fiber market," said Pankaj Kumar Tiwari, the company's deputy manager. "Because we witnessed a significant change in this market in 2018." He cited the reasons for the market change, he quoted The increasing use of basalt fibers in mash-up composites is due to growing demand in the automotive market and the attractiveness of basalt fiber recyclability coupled with its strength, which is said to be greater than E glass fiber.
A clear sign of doomed growth of basalt fiber composites is the recent construction of the first basalt fiber production plant in the United States at a cost of $ 20 million. Newer player in the industry, Irish Mafic, is building the plant in Shere, North Carolina, USA, and is expected to "fire up" in the third quarter of 2019.
The charm of basalt fiber
The concept of making fibers from basalt is not new. The first basalt fiber manufacturing patent was issued in 1923, and related personnel extensively studied its application in military hardware in the 1950s and 1960s. Even the major producers of fiberglass have explored the potential of basalt, although they abandoned this focus in the 1970s, focusing research and development on materials with better performance in fiberglass, including S-2 glass. Interest in the development of basalt fiber composites has been declining for decades, but this interest has continued to grow in recent years.
If the mined rock was originally formed by rapid cooling of lava rich in magnesium and iron, then it is no surprise that basalt fibers will exhibit excellent thermal and fire resistance, as well as extremely high operating temperatures. These important characteristics make basalt fibers a standard material for thermal insulation products in high temperature applications. For example, Russian basalt fiber producer Kamenny Vek provides a large number of products to the US automotive industry for thermal insulation of exhaust systems, and also provides products for industrial-use heat-resistant materials manufacturers.
In addition to thermal properties, the combination of basalt fiber strength, stiffness, impact resistance, and chemical inertness also makes it an attractive reinforcing material for composite materials. In FRP (fiber-reinforced plastic) applications, the molding of basalt fibers is similar to that of glass fibers. Almost any molding process that currently uses glass fiber can use basalt fiber as an alternative material, requiring only limited modification of key process conditions. Basalt fibers are compatible with any standard resin system.
Although the density of basalt (2.63 g / cm3) is slightly higher than that of glass fiber, other performance advantages make it a composite material that is even lighter and has better designability than glass fiber.
The thermal properties of basalt fibers have also attracted attention in applications other than non-composite insulation applications. In applications requiring a wider temperature range, opportunities for basalt fiber composites are increasing. Another characteristic, impact resistance, makes basalt fibers significantly better than glass and carbon fibers. For example, preliminary research conducted by the Center for Integrated Lightweight Structures in Aachen, Germany, and the Institute of Textile Technology, Aachen University of Technology showed that the specific energy absorption capacity of basalt fiber blended yarn fabric (HYWF) reinforced polyamide 6 is stronger than that of glass fiber HYWF Polyamide 6 is 35% higher and 17% higher than carbon fiber HYWF reinforced polyamide 6.
Iron and aluminum oxides in basalt bring other advantageous characteristics. For example, basalt fibers have better corrosion resistance and fire resistance than E glass fibers. In addition, a recent study conducted by Mafic in Ireland and the Fraunhofer Project Center in Canada confirmed that basalt fiber / epoxy test panels have higher tensile modulus, tensile strength, and interlaminar shear strength than the same resin. The E glass fiber / epoxy test board manufactured by the manufacturing process is 40% higher and 20% higher than the rigidity. Russia's Kamenny Vek reported similar results.
Basalt fibers have low water absorption and are important in construction and pipeline applications. Basalt fibers are not conductive. As a naturally occurring material, it is also easier to recycle than other reinforcing fibers, which is a factor considered by the automotive and other industries. In summary, Gencarelle describes basalt fibers as "slimer and greener" and more impact resistant than other reinforcing fibers. These characteristics indicate that basalt fiber composites are in the best price / performance ratio between E glass fibers and carbon fiber composites. As Thompson said, "We find ourselves filling the cost and performance gap between carbon fiber and glass fiber. This market has been eager for a product to fill this gap."
It is reported that transfer from carbon fiber to basalt fiber is easier than transfer from E glass fiber to basalt fiber, but both cases can be achieved. For carbon fiber, cost savings are usually the main reason to switch to basalt fiber. For those applications where carbon fiber exceeds performance requirements, basalt fiber can be competent for its cost performance advantage. In some applications, different failure modes of carbon and basalt fibers are also important. When carbon fibers are damaged, catastrophic "pulverization" often occurs; and basalt fibers undergo a more modest mode of failure on more than one occasion. For example, Streetman said: "When a carbon composite prosthesis fails, the user will fall; if a basalt composite prosthesis is used, the user will sit down."
Although the relative cost of basalt fiber decreases with the improvement of production methods, it is still more expensive than E glass fiber and is twice as expensive as E glass fiber in large-scale applications. Therefore, for higher cost applications, some extremes must be improved. Important performance characteristics to balance. These properties include: higher mechanical properties such as stiffness and strength, impact resistance, chemical resistance and water resistance, as well as differences in failure modes compared to glass fibers, which are more easily broken than basalt fibers.
Basalt Fiber Barriers
The basic manufacturing method of basalt fiber is very simple: just like glass fiber production, the molten raw material is drawn into filaments. Basalt is very efficient because it does not require other materials to make fibers. Some people say, "One pound of rock becomes one pound of fiber." The melting point of basalt at 1500 ° C is also comparable to glass. Because basalt is opaque, it is more difficult to heat uniformly than glass, which requires improved production methods, such as keeping the melt in the pool for a longer time, immersing the electrode in the pool, or using a two-stage heating scheme. These advances have been adopted in basalt fiber plants and are mature technologies.
In fact, the raw materials of basalt fibers are naturally occurring, which leads to a major technical obstacle: the raw materials have inconsistent properties. That is, rocks mined from different locations differ in the specific content of iron, magnesium, and other components. Key parameters vary by as much as 10%.
Variations in basalt fiber properties over the past few years have been a setback for expanding applications. Thompson explained: "When basalt fiber proves to be the best fiber for the application, customers cannot rely on the source, quality, and consistency of the raw materials, which means that their application cannot be commercialized." "Once you determine a consistent It's no longer a problem if it comes from the same source. "Mafic's Irish plant uses European materials, and it will use the same sources when it starts production in the US. But the company is also targeting an undisclosed U.S. source to supply raw materials to U.S. plants in the future. All fiber producers must carefully select the raw ore and pre-qualify it, which, together with the improvement of the production process, results in higher consistency.
Historically, the production of basalt fibers has been controlled manually, but fiber manufacturers are adding automated controls to improve product quality and consistency. Gencarelle reports that the basalt fiber manufacturing plant he represents has passed ISO 9000 certification. "They value quality control from raw materials to the entire process," he said.
As far as the market is concerned, basalt fiber manufacturers report that the biggest obstacle currently is regulation. "Many areas of the construction industry can only use materials that have been approved by the norm," Streetman explained. He mentioned that the Florida Department of Transportation is a "more forward thinking" agency that is nearing completion of its approval of basalt composite standard. Gencarelle also pointed out that the American Concrete Association has recognized that basalt composite bars meet the Association's requirements for concrete stiffeners. Nevertheless, much work remains to be done before the construction industry and other industries reach widespread acceptance of basalt composites.
Finally, and perhaps most importantly, basalt fiber producers find themselves in a "dilemma" situation, especially in relation to current E glass fiber applications. In a large number of such applications, the current fiber usage has exceeded existing capacity, and basalt fiber manufacturers can meet this gap. But even if basalt fibers are technically the most suitable, composite manufacturers don't want to switch to basalt fibers. Conversely, because a large basalt fiber plant takes two to four years to go into production, basalt fiber investors want to ensure that market demand emerges when the plant goes online.
Vitality of basalt fiber composites
If a basalt fiber manufacturer can point to one application that specifically represents the growth of basalt fiber composites, it is concrete stiffeners. Like glass reinforcement, basalt composite bars (hereinafter referred to as basalt bars) are much lighter than traditional steel bars. "In fact, it's over 70% lighter," Gencarelle said. "A person can easily lift a roll of 10m basalt tendons with a length of 100m." He continued that the advantages of basalt tendons over glass steel bars include natural rust, corrosion-resistant liquid and chemical properties. This makes it ideal for marine applications, chemical plants and other potentially corrosive environments. He added: "Moisture penetration in concrete does not cause it to crack, so it does not require a special coating like glass reinforced plastic." Gencarelle also emphasized the matching between the thermal expansion coefficient of basalt tendons and concrete. Its non-conductive nature also makes basalt tendons a good choice for buildings that include magnetic resonance imaging or data-intensive operations.
Gencarelle reports that they are doing some work to move the basalt tendon pultrusion plants to the United States, because such a move would help increase the market share of basalt tendons while avoiding tariffs and allowing these factories to compete for designated use. "Made in the USA" project.
Regulatory work is continuing. Basalt tendons have been incorporated into national building codes and are widely used in the construction industry in Russia, Ukraine and China. Oleg Kuzyakin, Commercial Director of Kamenny Vek, said: "In the United States, Canada, the United Kingdom, Italy and Poland, and some other countries, basalt tendons are widely used for applications that do not require certification, such as swimming pools and garden paths." These countries are doing basalt Tendon certification work. He added: "In some European countries, such as Germany and France, the process is more expensive, longer and more complicated than others, but we are also seeing increasing interest in basalt tendons in these countries."
The company also reports that a significant amount of its basalt fiber is used in compressed natural gas (CNG) bottles for buses, trucks and homes.
Another growing use is in composite pipes. Wavin Ekoplastik of the Czech Republic has developed a polypropylene pipe with a basalt fiber reinforced layer. Compared with glass fiber reinforced polypropylene pipes, the pressure resistance of the pipe at high temperatures has been increased by 50% and the flow rate has been increased by 20%.
Kamenny Vek's Australian partner, Basalt Fiber Technology, is supplying basalt fiber for marine applications. Many sporting goods are also using the company's fibers, although as Kuzyakin points out, these are not currently high-volume markets.
Kuzyakin reports: "In terms of usage, greater potential lies in wind energy use." "Wind energy is one of the most prominent uses. We consider it strategically important, but it is a long-term process because of the process of achieving compliance and certification Very long, complicated and expensive. "
As mentioned earlier, prosthetics and orthopedics benefit from a greater "endowment" of basalt fibers. In November 2018, "Composite Materials World" media reported an application from Coyote Design Company in the United States. Some of the company's customers have found the stiffness of carbon fiber-reinforced polymer composites uncomfortable and the rate of fracture of prosthetics high. The use of basalt fiber composites can significantly improve the bending performance of the prosthesis and reduce the rate of prosthesis destruction.
In sporting goods, a carbon / basalt fiber hybrid design is often used to take advantage of each fiber. There are many examples in the digital magazine "Basalt Today", including badminton rackets from Wilson Company in the United States, skis from Niche Company in the United States, and kayak paddles in the Canadian Nimbus Paddle Company.
The future seems to be here
Although major breakthroughs in basalt fiber composites have not yet been achieved, progress seems to have been made in all necessary areas, such as manufacturing efficiency and capabilities, global presence, product design and development, and regulatory activities. Thompson of Mafic in Ireland declared: "We think we are getting better today, and our customers have shown us that they believe this, as evidenced by their level of investment and their desire to see our US factory go online, . "
Thompson concludes that significant progress is expected over the next 12 to 24 months. "We are excited to be a new addition to the toolkit."