Patent EA-000600-B1 (EA)
Title: Method and device for manufacturing mineral fibres
Inventor: THAMM DIRK
IPC: C03B37/08
Filed: 1996-10-09
Abstract: 1. Process for producing mineral fibres from rock, vitreous technical wastes or technical glass wastes, in which after the mechanical separation of non-glass-containing and predominantly glass-containing products the predominantly glass-containing products having a particle size of less than 80 mm are melted at 1050 to 1480 degree C in a melting bath (1), where the melting bath (1) is connected to a forehearth (2) in such a manner that flow of the melt from the melting bath (1) into the forehearth (2) is enabled between melting bath (1) and forehearth (2) in the surface area of the melt, and where the melt is fed from the forehearth (2) to a feeder device, and where the melt is fed from the feeder device to a bushing device arranged there below and is taken off from there as filament with simultaneous solidification, characterized in that the melt is fed to the feeder device from a take-off area (8) of the melt in which the melt complies with the following conditions: a) the processing range of the melt is 40 to 100 K, b) the melt viscosity at 1450 degree C is 30 to 160 dPaxs, c) the melt viscosity at 1300 degree C is 200 to 1500 dPaxs, d) the quotient of the viscosity (in Paxs) and the surface tension (in N/m) is between 10 and 100, e) the energy of activation of the viscous flow of the melt is no greater than 290 kJ/mol; and f) the ratio of the height (hs) of the melt in the forehearth to the height (hw) of the melt in the melting bath is (hs):(hw) = (0.8 to 1.1):(2 to 6); and g) the ratio of the area of the melt surface (4) in the melting bath Fw (1) to the area of the melt surface (4) in the forehearth Fs (2) is 0.5 to 1.5. 2. Process according to Claim 1, characterized in that the ratio of the width (Bs) of the forehearth (2) to the width (Bw) of the melting bath (Bs):(Bw) = (0.8 to 1):(5 to 12). 3. Process according to Claim 1, characterized in that the ratio (hs):(hw) = (0.8 to 1):(2.5 to 5). 4. Process according to Claim 1, characterized in that the conditions in the take-off area (8) of the melt are maintained as follows - the processing range of the melt is 60 to 80 K - the melt viscosity at 1300 degree C is 200-1000 dPaxs - the melt viscosity at 1450 degree C is 40-150 dPaxs, - the energy of activation of viscous flow of the melt is no greater than 270 kJ/mol. 5. Process according to Claim 1, characterized in that the predominantly glass-containing products of rock are used without further additives. 6. Process according to Claim 1, characterized in that the melt is transferred from the melting bath (1) into the forehearth (2) via a baffle (15) arranged at the start of the forehearth (2). 7. Process according to Claim 1, characterized in that the melt is fed from the forehearth (2) to a that the melt is fed from the forehearth (2) to a flow feeder (5) or a flow block (17) as feeder device. 8. Process according to Claim 7, characterized in that the melt is fed to a flow feeder (5) which comprises an open tube (7) or a group of open tubes (7) which are arranged in the bottom of the forehearth (2), where the upper end of each tube (7) is open and inserts into the melt of the forehearth (2) up to the take-off area (8), and where the lower end of each tube (7) is open so that at least the melt situated above the tube (7) enters into the tube (7) and runs to the bushing device arranged beneath it. 9. Process according to Claim 8, characterized in that the melt is introduced into one or more tubes (7) of a flow feeder (5), the top edge of which is in the take-off area (8) of the melt. 10. Process according to Claim 8, characterized in that the melt enters into the tubes (7) of the flow feeder (5) through orifices in the curved surface of the tubes (7) and through the ends of the tubes (7) which are open at the top, all orifices lying in the take-off area (8) of the melt. 11. Process according to Claim 1, characterized in that the temperature and/or the viscosity of rock melts is dependent by the ratio Fe<2+> to Fe<3+> by controlling the redox conditions in the melting unit. 12. Process according to one of Claims 1 to 11, characterized in that the fibres are drawn to form a continuous fibre having a filament diameter in the range of 2 to 400 μm, preferably 5 to 150 μm, in particular 5 to 25 μm. 13. Process for the manufacture of mineral fibres from rock, vitreous technical wastes or technical glass wastes, in which after the mechanical separation of non-glass-containing and predominantly glass-containing products the predominantly glass-containing products having a predominantly glass-containing products having a particle size of less than 80 mm are melted at 1050 to 1480 degree C in a melting bath (1), where the melting bath (1) is connected to a forehearth (2) in such a manner that flow of the melt from the melting bath (1) into the forehearth (2) is enabled between melting bath and forehearth in the surface area of the melt, and where the melt is fed from the forehearth (2) to a feeder device, and where the melt is fed from the feeder device to a bushing device arranged there below and is taken off from there as filament with simultaneous solidiflcation, characterized in that the melt is fed to the feeder device from a take-off area (8) of the melt in which the melt complies with the following conditions: a) the processing range of the melt is 40 to 100 K, b) the melt viscosity at 1450 degree C is 30 to 160 dPaxs, c) the melt viscosity at 1300 degree C is 200 to 1500 dPaxs, d) the quotient of the viscosity (in Paxs) and the surface tension (in N/m) is between 10 and 100, e) the energy of activation of the viscous flow of the melt is no greater than 290 kJ/mol; and f) the ratio of the height (hs) of the melt in the forehearth to the height (hw) of the melt in the melting bath is (hs):(hw) = (0.8 to 1.1):(2 to 6); g) the ratio of the area of the melt surface (4) in the melting bath Fw (1) to the area of the melt surface (4) in the forehearth Fs (2) is 0.5 to 1.5; h) the difference between the lower processing temperature and the liquidus temperature of the melt is not less than 50 degree C; and in which the filaments are drawn beneath the bushing device by a hot gas stream conducted horizontally and/or at an incline to the drawing direction to form short fibres having a diameter of 0.5 to 7μm. 14. Apparatus for the manufacture of continuous mineral fibres from rock, vitreous technical wastes or technical glass wastes, comprising a beatable melting bath (1), a forehearth (2) connected to the melting bath (1), which forehearth is arranged in such a manner that the melt surface (4) in the melting bath (1) is essentially at the same level as the melt surface in the forehearth (2), a feeder device which is arranged in the melt in the forehearth and has an essentially vertically orientated outlet (9) through the bottom (6) of the forehearth (2) and a bushing device at the end of the outlet out of the feeder device having thread winder devices (14) arranged downstream therefrom, characterized in that the the melting bath (1) is designed in such a manner that the ratio of height (hs) of the melt in the forehearth (2) to the height (hw) of the melt in the melting bath (hs): (hw) is adjustable = (0.8 to 1.1): (2 to 6) and the flow feeder (5), which is formed either by tubes (7) or one or more flow blocks (17), in the case of tubes (7) [lacuna], these are movable through the bottom orifices of the forehearth (2) at least to the extent that the quotient of the depth of submergence (hET) to the height (hO) of the melt layer above the upper edge of the tube is 0.25 to 4. 15. Apparatus according to Claim 14, characterized in that the melting bath (1) is designed having a bottom (3) which can be changed in a vertical direction. 16. Apparatus according to Claim 14, characterized in that the flow block (17) is a plate arranged in the bottom of the forehearth (6) having a flow-through orifice (19) in its central region, the flow-through orifice being enclosed by a flow ring (18) essentially completely surrounding it. 17. Apparatus according to Claim 16, characterized in that the ratio of the cross-section (F.delta) of the flow-through orifice to the total area (SIGMA.FD) of the nozzle orifices/cross-section of the nozzles in the nozzle plate is (F.delta): (SIGMA.FD) = 10-50. 18. Apparatus according to Claim 14, characterized in that, in the region of the melt between the melting bath (1) and the forehearth (2), a baffle (15) starting from the bottom (6) of the forehearth and a skimmer block (16) starting from the melt surface (4) are arranged. 19. Use of a continuous fibre drawn according to one of Claims 1 to 12 for the manufacture of woven fabrics, non-woven articles and composites. 20. Use according to Claim 23 for the manufacture of short fibres having defined geometric dimensions.