BASALT FIBRES AND COMPOSITE MATERIALS ON THEIR BASIS
RUSAKOV A.V.
One of urgent tasks of resource-saving is the development advanced materials production meeting requirements of designing up-to-date machines, mechanisms and devices.In 1999 with the purpose of realisation of the basic regulations, containing in the report of the President of the Republic of Uzbekistan on the XIVth session of Oliy Mazhlis, and the Decision of the Cabinet of the Ministers RUz of 10.06.99 No. 296 measures on organisation in Uzbekistan manufacture of heat-isolation materials appropriate to the international standards on power efficiency and ecological safety with use of local raw material in volumes, necessary for tasks performances stipulated by the power engineering development program have been developed.
For one of such advanced materials - basalt fibre - the raw material is basalt rocks - widespread shed volcanic rocks with large hardness and fragility. The basalts are used in building purpose as crushed and quarry stone. Recently from them stone moulding is received used with success for manufacturing acid-resistant chemical equipment, pipes, facing materials.
With the help of the newest technologies from basalt superthin and continuous fibre are already received, on the basis of which various perspective composite materials are produced.
The stocks of basalt deposits in Uzbekistan found at spurs of Kuramin, Chatkal, Ghissar and North-Nurata mountains, on a tentative estimation exceed 32 000000 m3.
The most significant stocks of Ghavasai basalts of Kuramin ridge in the Namangan area are characterised by non-uniform chemical and mineral composition, basically are represented by porphyry structure with various content of a volcanic glass, extensive sites of holocrystalline dolerite basalts and diabases.
Occuring in valleys of Asmansai river and Lakchisay river of North-Nurata ridge basalts of the basic composition alternate with black ultra basic basalts-picrites containing no more than 42% silica and without plagioclasses.On the basis of long-term researches of basalts as raw material for obtaining various kinds of fibre carried out at scientific establishments of Uzbekistan, Ukraine and the Russian Federation, rock melts are classified by a degree of their viscosity, and also four basic groups have been distinguished:
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High-viscous: h at 1450° Ñ - more than 150 ¶Pà.ñ, at 1300° Ñ - more than 1000 ¶Pà.ñ. |
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Viscous: h at 1450° Ñ - 50-150 ¶Pà.ñ, at 1300° Ñ - 200-1000 ¶Pà.ñ. are recommended basically for obtaining continuous fibre. |
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Average-viscous: h at 1450° Ñ - 30-50 ¶Pà.ñ, and at 1300° Ñ - 100-200 ¶Pà.ñ. are recommended mainly for manufacture of superthin fibres. |
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Low-viscous: h at 1450° Ñ - less than 30 ¶Pà.ñ, and at 1300° Ñ - less than 100 ¶Pà.ñ. are recommended as optimum for manufacture spun fibre. |
Limits of viscosity for a concrete kind of fibre with reference to existing ways of manufacture and temperature close to 1300° Ñ are now specified. Melts for continuous fibre should have temperature of the top limit of crystallisation - not more 1250° Ñ, viscosity at temperature 1300° Ñ - 300-1100 ¶Pà.ñ., temperature interval of manufacture - not less than 70° Ñ.
It has been defined, that on technological properties diabases melts of Asmansay show are comparable with Berestovetsk basalts (Ukraine).
The fibre obtained from basalts, have high water resistance (90.0-99.9 %), heat resistance (650-800° Ñ) depending on a type of rock), and on acid resistance considerably tops mineral cotton wool. Now there are three methods of obtaining fibre from rock - centrifugal-blowing, centrifugal -multiroll and die- blowing. The share of the first manufacture makes 85-87% of total volume, that is caused by simplicity of design of the process equipment. The losses at this method are equal to 30-55%, of nonfibrous inclusions content in a product -15-25%, average density of cotton wool - 85-100ñò/m3. Die- blowing method ensures obtaining high-quality products from single-component raw material. The content nonfibrous inclusions ("kinglet") - 1,0-5 %, loss - about 1%. The centrifugal-multiroll method is applied less often because of complexity of manufacture. In Uzbekistan the module-block installation for obtaining a basalt superthin fibre (BSF) from single-component raw material has been developed. The finished product - cloth - consists of bound among themselves and is kept by forces of fibres own coupling, dimension 1200õ2500 mm, thickness 50-300 mm. The basic parameters of cloth from a basalt superthin fibreParameter |
Mark of a cloth |
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BSF-ÑÒ |
BSF-ÑP |
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Mean diameter of a fibre, micron |
2,0 – 3,0 |
1,5 – 2,0 |
Share of nonfibrous inclusions, %, no more |
8,0 |
4,8 |
Density, kg/m3 |
23,0 |
20,0 |
Heat conductivity,V/m2at 25îÑ |
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Factor of a sound absorbtion for frequencies from 100 up to 2000 Hz |
0,85 – 0,96 |
0,85 – 0,98 |
Limiting temperature, ° Ñ |
700 |
700 - 900 |
Humidity, %, no more |
2,0 |
1,0 |
Module-block manufacture of BSF is ecologically sound is clean due to application of chambers of dry clearing and thin filters of air clearing, requires the minimum quantity of water for cooling the equipment.
Because of low heat conductivity BSF is used for isolation of internal and external facings of buildings, and also as a sound-proof material for noise suppression of the industrial equipment.
By results of marketing researches carried out by on Technology Transfer Agency of the SCST RUz, the need in heat insulation materials from BSF in the republic makes 150 thousand m3/year.
In the republic the technology of a basalt continuous fibre (BSF) production has been developed and preconditions on manufacturing the non-standard equipment at the industrial enterprises of Uzbekistan have been created.
The flow chart of BSF manufacture - preparation of raw material ® Melt obtaining in molten pool furnace ® Melt puncturing in feeder part ® Lubrication and stretching primary strings - winding on the reel ® Maturing cloth at an intermediate warehouse ® Rewind of a complex string in rowing by twisting.
From basalt rowing it is possible to produce basalt plastics, weaved and non-weaved materials, chopped fibre and many other composite materials described by high strength and specific rigidity, heat resistance, wear resistance, good electrical- and heat-insulation, radio absorbing and other properties. They are ecologically clean and are competitive with the best traditional materials -asbestos, polyurethane foam, glass wool etc.
The technology of basalt fibre processing corresponds to traditional methods of glass fibre production. The excellent properties of basalt fibre open prospects of their use in manufacture of heat -, alkali -, acid-resistant products, and also in quality ecologically clean substitutes of asbestos fibre .
The struggle for metal economies provides wide introduction in manufacture of economically favourable substitutes. One of such substitutes is the stone moulding, its area of application extends constantly. Now from basalt moulding more than 100 kinds of alkali-resistant and acid-proof industrial products are produced.
The conditions in Uzbekistan are favourable for development stone moulding industry owing to the large stocks of various rocks, serving as raw material for stone moulding, availability of electricity, advanced industry, qualified experts, allowing already in the near future to create a new branch in the republic.
The products from stone moulding will enable to replace pig iron, manganese and alloyed steel, lead, copper and other ferrous and non-ferrous metals.
The creation on the basis of basalt fibre of composite materials with high physical-mechanical and special physical-technical properties will allow Uzbekistan to rise to the scientific and technical progress in power and mechanical engineering, construction, transport and in many other areas of national economy.
