JEC COMPOSITES MAGAZINE - Issue #68 Special JEC Asia - October 2011 - 22

basalt

Continuous basalt fibre (CBF):
a natural fibre for composite applications
Basalt is a natural resource of geological origin that accounts for 80% of the Earth’s crust, so there is no problem of limited access to the raw material. The physico-chemical and mechanical properties of continuous basalt fibres make them competitive with standard E-glass and highperformance S2-glass fibres in composite applications.
significant improvements were made to enhance the mechanical properties of basalt fibres and to lower production costs. (corrosion-resistant), boron-free E-glass, and HP (highperformance) glass fibre. The main components of E-glass fibre are SiO2 (53-60%), Al2O3 (510%), CaO (18-22%), MgO (57%) and B203 (close to 0% now for environmental reasons). CBFs contain no B2O3, but do have the other four oxides (SiO2, Al2O3, CaO, MgO), along with significant quantities of Fe2O3, Na2O, K2O and TiO2. A typical native basalt composition would be: SiO2 = 55-65% Al2O3 = 10-20% MgO = 5-15% Sum FeO, Fe2O2, Fe2O3 = 8-15% CaO = 6-10% TiO2 = 0.5-3% Na2O + K2O = 3-5% The dark colour is due mainly to the combined presence of iron and magnesium oxides, with the other mineral oxides (CaO, TiO2, etc.) having more or less of an effect. Depending on the relative proportions of these elements, you obtain a range of basalt-fibre shades that go from dark brown to gold to dark green. These variations can be observed by comparing different basalt fibre samples. At relatively small thicknesses (< 1 mm), molten basalt appears totally opaque. To get a fairly

he Ukraine Scientific Research Institute in the former Soviet Union produced the first CBF samples back in the 1960s, and commercial production of CBF started in 1985. As of 1997,

Comparison of CBF and glass-fibre chemical compositions
Glass fibre is generally classified into four large families: E, ECR

jec composites magazine / No68 October 2011

interview

magma rock areas. Basalt density ranges from 2,520 to 2,970 kg/m3. Basalt fibre is made by melting natural basalt stone. As long as no additives are used during the melting process, the fibre structure remains the same as the natural stone. Therefore, basalt fibre can be considered as a natural fibre. JCM: How do you produce basalt fibre? O.S. : Crushed rock is charged into a melting furnace using a dozing charger and starts to melt at a temperature of 1,460-1,500°C in the furnace bath. Then the molten rock is extruded through a platinum-rhodium bushing with 200 holes. A sizing is applied to the surface of the fibres using an applicator. Afterwards, the resulting roving is gathered into bundles and taken to a cutting machine where it is chopped to a certain length. JCM: What are the main forms of basalt fibre (manufacturing volumes, sizing, bundle size)? O.S. : The main forms of basalt fibre are: - Direct roving: continuous fibre wound as “cakes” and ready for sale. The main advantage of direct

OKSANA SHVED SALES MANAGER TECHNOBASALT-INVEST LLC

JEC Composites Magazine: What is the current situation with basalt raw materials? Are there any limitations, as is the case with petrochemical materials? Can a basalt fibre be considered as a natural fibre? OKSANA SHVED : Basalt is the most common type of magmatic rock found on the surface of the Earth. The colour of basalt can range from dark grey to black and its chemical structure can be extremely varied. The structure of basalt depends on the magma crystallization process and on the length of time needed for the rock to form. Basalt deposits are almost unlimited and cover approximately 30% of

roving is its zero catenary and excellent aspect. As a rule, direct roving is used to weave fine fabrics or for specific applications. Most customers need rovings with a much higher linear mass density such as 1200, 2400 or 4800 tex. In this case, assembled rovings are used. - Assembled roving: continuous basalt fibre strands drawn and then joined together using assembling machines at the production facility. - Twisted yarn: made by twisting basalt continuous roving together using specific machines. It is suitable for textile production, sewing, crocheting, knitting, weaving, embroidery and ropemaking. - Chopped basalt fibres: produced from continuous basalt roving either on drum-type choppers installed independently from the furnace or on choppers connected in-line with the furnace. Wet chopped strands are used to produce textile paper and in some concrete reinforcement technologies, as an alternative to steel and polypropylene fibres. In such applications, a water-compatible sizing is required to improve the distribution of strand monofilaments in the matrix. Dry chopped strands are generally used

JEC COMPOSITES MAGAZINE - Issue #68 Special JEC Asia - October 2011

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