A glass composition is provided that includes about 55.0 to 60.4% by weight SiO.sub.2, about 19.0 to 25.0% by weight Al.sub.2O.sub.3, about 8.0 to 15.0% by weight MgO, about 7 to 12.0% by weight CaO, less than 0.5% by weight Li.sub.2O, 0.0 to about 1.0% by weight Na.sub.2O, and 0 to about 1.5% by weight TiO.sub.2. The glass composition has a fiberizing temperature of no greater than about 2,500° F. Glass fibers formed from the inventive composition may be used in applications that require high stiffness, and low weight. Such applications include woven fabrics for use in forming wind blades and aerospace structures.

A glass composition is provided that includes about 57.0 to 62.0% by weight SiO.sub.2, about 20.0 to 25.0% by weight Al.sub.2O.sub.3, about 8.0 to 12.5% by weight MgO, about 7 to 9.0% by weight CaO, about 0.4 to 1.0% by weight Li.sub.2O, 0.0 to about 1.0% by weight Na.sub.2O, about 0 to 0.5% by weight K.sub.2O; and 0.2 to about 1.5% by weight TiO.sub.2. The glass composition has a fiberizing temperature of no greater than about 1,300 C. Such applications include woven fabrics for use in forming wind blades and aerospace structures.

A glass composition is provided that includes about 57.0 to 62.0% by weight SiO.sub.2, about 20.0 to 25.0% by weight Al.sub.2O.sub.3, about 8.0 to 12.5% by weight MgO, about 7 to 9.0% by weight CaO, about 0.4 to 1.0% by weight Li.sub.2O, 0.0 to about 1.0% by weight Na.sub.2O, about 0 to 0.5% by weight K.sub.2O; and 0.2 to about 1.5% by weight TiO.sub.2. The glass composition has a fiberizing temperature of no greater than about 1,300 C. Such applications include woven fabrics for use in forming wind blades and aerospace structures.

Herein is described a process for drying wet glass fibre forming packages, the process comprising: providing a wet glass fibre forming package comprising a strand of glass fibres with an aqueous sizing applied to the glass fibres; and subjecting the wet glass fibre forming package to microwave radiation having a frequency in the range of about 750 to about 1050 MHz.

Herein is described a process for drying wet glass fibre forming packages, the process comprising: providing a wet glass fibre forming package comprising a strand of glass fibres with an aqueous sizing applied to the glass fibres; and subjecting the wet glass fibre forming package to microwave radiation having a frequency in the range of about 750 to about 1050 MHz.

The invention provides methods of making man-made vitreous fibres (MMVF), comprising providing an electric furnace having molybdenum electrodes, providing mineral raw material, wherein the mineral raw material comprises (a) particulate material that comprises metallic aluminium and (b) other mineral component, introducing the mineral raw material into the furnace, melting the mineral raw material to form a mineral melt, and forming MMVF from the mineral melt, with the benefit of reduced shrinkage of consolidated MMVF products.

The invention provides methods of making man-made vitreous fibres (MMVF), comprising providing an electric furnace having molybdenum electrodes, providing mineral raw material, wherein the mineral raw material comprises (a) particulate material that comprises metallic aluminium and (b) other mineral component, introducing the mineral raw material into the furnace, melting the mineral raw material to form a mineral melt, and forming MMVF from the mineral melt, with the benefit of reduced shrinkage of consolidated MMVF products.

The present disclosure provides a novel glass composition that has a low permittivity and is suitable for mass production. A glass composition provided satisfies, in wt %, for example, 40≤SiO.sub.2≤60, 25≤B.sub.2O.sub.3≤45, 0≤Al.sub.2O.sub.3≤18, 0<R.sub.2O≤5, and 0≤RO≤12, and satisfies at least one of: i) SiO.sub.2+B.sub.2O.sub.3≥80 and SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3≤99.9; and ii) SiO.sub.2+B.sub.2O.sub.3≥78, SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3≤99.9, and 0<RO<10. Another glass composition provided includes SiO.sub.2, B.sub.2O.sub.3, Al.sub.2O.sub.3, R.sub.2O, and 3<RO<8 at the same contents as the above, and satisfies SiO.sub.2+B.sub.2O.sub.3≥75 and SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3<97, where R.sub.2O═Li.sub.2O+Na.sub.2O+K.sub.2O and RO═MgO+CaO+SrO.

The present disclosure provides a novel glass composition that has a low permittivity and is suitable for mass production. A glass composition provided satisfies, in wt %, for example, 40≤SiO.sub.2≤60, 25≤B.sub.2O.sub.3≤45, 0≤Al.sub.2O.sub.3≤18, 0<R.sub.2O≤5, and 0≤RO≤12, and satisfies at least one of: i) SiO.sub.2+B.sub.2O.sub.3≥80 and SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3≤99.9; and ii) SiO.sub.2+B.sub.2O.sub.3≥78, SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3≤99.9, and 0<RO<10. Another glass composition provided includes SiO.sub.2, B.sub.2O.sub.3, Al.sub.2O.sub.3, R.sub.2O, and 3<RO<8 at the same contents as the above, and satisfies SiO.sub.2+B.sub.2O.sub.3≥75 and SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3<97, where R.sub.2O═Li.sub.2O+Na.sub.2O+K.sub.2O and RO═MgO+CaO+SrO.

Methods and apparatus for producing fibers from igneous rock, including basalt include heating igneous rock by electrical conductive coils to achieve an homogenous melt and forming homogenous fibers from the melt.