Patent ID: 8037719

Claim:
A method for manufacturing basalt filament, comprising the steps of: grinding basalt rock as a material; washing a resultant ground rock; melting the ground rock that has been washed; transforming a molten product into fiber; and drawing the fiber in an aligned manner, and winding it, wherein the temperature of the molten product in the melting step is 1400 to 1650° C., and wherein log η is 2.15 to 2.35 dPa·s, where η is the viscosity of the molten product, wherein the basalt rock material comprises a mixture of a high-temperature basalt rock ore and an intermediate-temperature basalt rock ore, an amount of Al 2 O 3 in the high-temperature basalt rock ore is substantially the same as an amount of Al 2 O 3 in the intermediate-temperature basalt rock ore, and an amount of SiO 2 in the high-temperature basalt rock ore is larger than an amount of SiO 2 in the intermediate-temperature basalt rock ore.