Induction Melting of Basalt for Spun Fiber
Background
It has been a poorly kept secret for over a decade that fibers made from melted basalt rock have the potential to radically change the composite and concrete reinforcement fiber markets. There are many reasons for this, chief among them the superior properties of these fibers as compared first to standard e-glass fiberglass, and to a lesser extent, advantages over more advanced and higher priced fibers. In a brief summary, these advantages include:
High tensile strength
High modulus
Great heat resistance
Resistance to acids and alkali
Complete absence of water absorption and transmission through the interior of the fibers.
Today, e-glass fibers cost less than basalt fibers. However, there are forty years of production plant development behind the price of glass fibers, while basalt fiber production is still in its relative infancy. But there is a factor that may well level these price differences. The raw ingredients for making glass fibers now exceed $250 per ton, and the cost is steadily heading higher. Basalt filaments are made solely from crushed basalt rock, melted and then drawn into fibers. A recent quotation for crushed basalt rock was $3.75 per cubic yard at the quarry, which translates to $1.25 per ton. The supply of basalt rock suitable for making fiber is truly inexhaustible.
Current State of the Industries
At this point a brief comparison of the current process of making glass fibers and basalt fibers is warranted. Continuous glass fibers are made by heating either pre-manufactured glass balls or the mixture of ingredients that make glass in a large furnace. The melted glass flows into a forehearth, where the glass melt is drawn through a matrix of holes in platinum-rhodium alloy fixtures called bushings. The resulting fibers are drawn down, or attenuated, to much smaller diameters, usually ranging from 10 microns to 28 microns. The drawing and attenuation is powered by special high-speed winders stationed below the bushings.
All current basalt production uses furnaces that are descriptively very similar. There are two competing designs for basalt production furnaces, but both use a melting chamber in a furnace, and the resulting melt is drawn through the same type of platinum-rhodium alloy bushings. Again the drawing and attenuation is powered by winders.
There are enough technical differences in the successful design of a production furnace for glass and basalt to prevent any easy conversion of glass furnaces to basalt furnaces. Because of the radically different heat emission rates of the clear glass melt and the nearly opaque basalt melt, the critical internal dimensions are quite different. In addition, while glass production currently uses bushings with 1,000-2,000 tips (holes) producing up to 2,000 fibers simultaneously, basalt production is dominated by 200 and 400 tip bushings, with 800 tip bushings a near-term possibility. The result of this is that output of a basalt furnace per bushing is a fraction of the output of a modern glass furnace, and the opportunity cost of a bushing station is correspondingly considerably higher. While it is possible that basalt bushing technology will catch up to the current state of glass bushings, the last ten year history does not increase confidence in this progress.
One final comparison of the industries should be made here. Basalt filaments are quite inert, and no public health issues are on the horizon. In contrast, the plaintiff’s attorney’s bar is currently circling the fiberglass industry to see if their successful persecution of the asbestos industry can be repeated. Also, production of basalt fibers involves no noxious chemicals in the fiber production process, with carbon dioxide from the gas used to heat the furnaces the only real emission from basalt production. Again in contrast, several problematic chemicals are used in glass productions, some of which can still be found in the finished product.
The Future
Today the production of basalt fiber products is tiny compared to e-glass production. There are currently four plants that can be considered to be in commercial production, two in China, and one each in Ukraine and Russia. At least three more are in early production stages in Austria, Russia, and China. Two very small plants produce nominal amounts in Georgia and Ukraine. Total production does not exceed 10,000 metric tons, or less than 22 million pounds. Revenues are not available, but estimating from raw fiber production, world-wide revenues probably do not exceed fifty million dollars. This is not currently a large industry worldwide.
Knowledgeable insiders have assured us that basalt consumption would soon make a strong breakout, and become a mass item. This breakout has been predicted for 2-3 years down the road for the last decade. Yet the irony today is that none of the plants mentioned is believed to be operating on the logical 24/7 year-long schedule that this type of plant demands to be efficient. There are several reasons for this.
Basalt fibers cost more than e-glass at all volume levels of purchasing.
The largest consumers of e-glass individually consume more than the entire worldwide production of basalt fibers.
The process of adaptation of new products in industry is very slow, and many potential customers are still in the 2-3 year process of evaluation and production adaptation.
It should be emphasized that today there is much interest in basalt fiber products. Inquiries are at very high levels in the pre-cast concrete industry, in the composite industry, and in general construction. There are very real projects that will demand high levels of basalt purchases if they come to fruition. But this does not mean that there are today large customers ready to issue purchase orders and write checks. Basalt is still the fiber of the future. One can only hope to be ready with production when the demand becomes current.
Types of Production Technologies
Current production facilities for basalt fibers fall into two designs, both originating in Russia. One design follows fiberglass patterns, with large horizontal furnaces feeding into a forehearth feeding multiple bushings. The leading factory in Russia is an example of this production.
The second pattern uses vertical furnaces with a melting chamber directly over a single bushing. This pattern is used in Ukraine, and both major plants in China. Production is increased by building multiple furnaces until the desired output is achieved.
Recently a new design has been revealed. Currently best described as induction melting, it was entirely designed in the United States over a 30+ year course of experimentation. It is unique in that it does not use bushings—it forms the fibers using a system of thermally stable spinner heads, and melts the basalt with a proprietary induction furnace. Instead of drawing the fibers using a winder, it employs a patented air-flow system to attenuate and control the movement of the fibers.
A comparison of the costs and outputs of the various systems is appropriate here.
Single-bushing Vertical Furnaces
A current commercial offer to build this type of plant calls for an investment of $15,000,000 for a plant producing 4.4 million lbs. of basalt fiber per year. Estimated variable production costs for this plant if built in the US would be somewhat under $1 per lb. Estimates for production in China are considerably less.
Horizontal Furnaces
There are theoretical advantages to this design, including a much better surface area to volume ratio, reducing heat losses, and easier design of work stations, with one operator able to manage several bushings. A current engineered estimate of cost and output is not available, but for purposes here, it will be assumed to have a 20% advantage in cost related to output, and a somewhat lower production cost. Please consider the numbers in the chart below to be best-effort estimates.
The Induction System
This bushing-less design has demonstrated only under private conditions, also in industry under tight NDS with good success and is purported to be developed to production-ready condition. It specifies a production machine line that can produce 16 million lbs., approx., depending on the flow chemistry, of spun fiber per year. The estimated cost of a production line is $2.5 million dollars. This does not include in-feed systems or the take-up systems on the final end. This plant is unique in that it does not burn any natural gas to heat the basalt, using only electricity to power the induction furnace.
A recap of these options makes the comparison clearer:
Type Cost, Millions USD Output, Tons Capital Cost of Ton of Annual Output, USD Estimated Variable Cost, Lb., USD
Vertical 15 2,200 $6,818 $0.80
Horizontal, 15 2,600 $5,770 $0.60
Induction System (Spun) 0.7 8,000 $125 $0.05
Even a cursory examination of these numbers shows that anyone contemplating entering the market for basalt fiber products would need to consider the Induction System production processes before building a conventional plant. It must be emphasized that even though the inventor has a very high level of confidence in his technology, it has been demonstrated in industry only under tight confidentiality agreements.
However, the cost advantages are overwhelming. Here is a brief examination of the direct costs of producing fibers in both the continuous filament machine and the spun-fiber machine. Labor costs are ignored here, but they certainly do not equal the other direct costs due to the high output of both machines.
Estimated Direct Costs of Induction System Production
Electricity It takes energy to raise basalt rock from ambient to molten temperatures. The estimated heat required is 455 kwh per ton of basalt rock. This translates to 0.2274 kwh per lb. of rock melted. At $0.05 /kwh, this would be $.0011/lb, at $0.10/kwh it would be $0.023/lb. Allowing a very pessimistic 50% efficiency, we can be sure that the cost of melting the rock will not exceed $0.05/lb.
Intellectual Property Protection
IP protection is a very important consideration when evaluating an investment opportunity. Discussions with the Inventor have revealed the following facts:
The production process can be divided into three separate processes, the induction melting system, the filament forming wheel, or spinnerets, and the central air control system.
The use of induction heating has been used for the melting and tempering of metals for at least 80 years. Unlike metals, basalt is non-conductive and will not couple with the induction field. The inventor has developed and proven out IP on elevating basalt rock to and above the melting point using proprietary crucible ceramics that couple to the induction field. Both the crucible materials and the induction field coils are built under license only for him. These cannot be copied or replaced with any other materials.
The patented air system performs numerous levels of heating and cooling of the induction system and the spinning of the filaments. It is instrumental in attenuating the fibers from their relatively large diameter as spun to the 9-20 micron diameter required by industry. The air system is also used for mass filament control and orientation of filaments after they leave the spinnerets. It also functions as a closed-loop air filtration system that keeps any hazardous filaments and particulates out of the workspace air for worker protection. Filtered air is regulated down to 2 microns through HEPA filtration. The HEPA filters are built for him under license. Without this air system the induction and spinnerets will not produce filaments.
Spun basalt fiber goes back to the early 1900’s when it was spun and compressed into rock wool insulation for industrial and residential insulation. International Rock Wool still produces large quantities of rock wool insulation for industrial and shipyard uses. This spinneret system is an off take of this old technology. Using proprietary technology in the spinneret and its drive system along with the air system it becomes possible to deliver a more uniform and higher quality filament without the dust and particulates that the older systems were prone to produce.
With the main system patented, and then surrounding it with multiple levels of IP and licensed suppliers it would be impossible to replicate the fiber system and have it function at all.
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