Method for producing mineral wool

Abstract

The present invention relates to a method for producing mineral wool having a chemical composition, expressed as a percentage by weight of oxides, comprising: SiO2 30-50% Al2O3 15-35% CaO 5-25% MgO 1-25% Fe2O3 2-15% Na2O + K2O >10% said method comprising providing a mixture of raw materials, melting said mixture of raw materials to obtain a molten material, and fiberizing the molten material; characterized in that the mixture of raw materials comprises at least 8.5% by weight of a recycled raw material comprising at least 3% of magnesium, expressed by weight of oxides, said recycled raw material being substantially free of carbonates, and in that the mixture of raw materials is free of dolomite and magnesia.

Dependencies are inferred from the claim text.