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.

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.

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.

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.

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.

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.

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.

The present invention is directed to an inductively heated bushing box and fiber formation method for an igneous rock melting furnace. The bushing box includes side walls with a water cooling system surrounded by one or more induction coils for maintaining and even temperature distribution of melted charge before the melt is extruded through tips of a bushing plate. The bushing plate is offset from the bottom of the one or more induction coils to avoid end effects and better ensure consistent eddy current formation. By increasing the uniformity of temperature distribution over a larger surface area, the system allows for a greater number of tips per bushing plate, and therefore provides for greater efficiency.

One subject of the invention is a process for manufacturing a glass, the chemical composition of which comprises at least 3% by weight of iron oxide, expressed in the form Fe.sub.2O.sub.3, comprising a step of electric melting, using electrodes submerged in the molten glass, of a vitrifiable batch material mixture containing at least one manganese carrier wherein the manganese is in an oxidation state higher than +2.

One subject of the invention is a process for manufacturing a glass, the chemical composition of which comprises at least 3% by weight of iron oxide, expressed in the form Fe.sub.2O.sub.3, comprising a step of electric melting, using electrodes submerged in the molten glass, of a vitrifiable batch material mixture containing at least one manganese carrier wherein the manganese is in an oxidation state higher than +2.