A mineral wool panel, intended to be used as an acoustic panel, has a surface density of greater than or equal to 3.2 kg/m.sup.2, an air flow resistivity of between 30 and 120 kPa.Math.s/m.sup.2, and a Young's modulus of between 0.5 and 4 MPa.

A mineral wool panel, intended to be used as an acoustic panel, has a surface density of greater than or equal to 3.2 kg/m.sup.2, an air flow resistivity of between 30 and 120 kPa.Math.s/m.sup.2, and a Young's modulus of between 0.5 and 4 MPa.

A glass wool panel, intended to be used as an acoustic panel, has a density of less than or equal to 130 kg/m.sup.3, an air flow resistivity of between 30 and 120 kPa.Math.s/m.sup.2, a Young's modulus of between 0.5 and 4 MPa.

A glass wool panel, intended to be used as an acoustic panel, has a density of less than or equal to 130 kg/m.sup.3, an air flow resistivity of between 30 and 120 kPa.Math.s/m.sup.2, a Young's modulus of between 0.5 and 4 MPa.

Fibrous material webs and methods of making the fibrous material webs. Binderless webs can be formed in a continuous process where fiber material, such as glass is melted and formed into fibers. The fibers are formed into a web of binderless glass fibers or a web with a dry binder. The binderless web or the web with dry binder can be layered and/or the fibers that make up the web can be mechanically entangled, for example, by needling.

Fibrous material webs and methods of making the fibrous material webs. Binderless webs can be formed in a continuous process where fiber material, such as glass is melted and formed into fibers. The fibers are formed into a web of binderless glass fibers or a web with a dry binder. The binderless web or the web with dry binder can be layered and/or the fibers that make up the web can be mechanically entangled, for example, by needling.

Provided is a cooling water spray apparatus including a plurality of spinners disposed to be adjacent to one another along a travel path of a target to be cooled, and a plurality of cooling water spray holes provided on each spinner and configured to spray cooling water. The plurality of spinners may be non-overlappingly disposed with respect to one another.

The invention relates to a method of preparing a mineral melt in a cupola furnace that uses at least one plasma torch to provide heat energy to the furnace. The plasma torch uses nitrogen, carbon monoxide, carbon dioxide, or a mixture thereof as the carrier gas. The invention also relates to a cupola furnace for the preparation of the mineral melt, and the use of a plasma torch in a cupola furnace to reduce the amount of NO.sub.x and/or hydrogen in the furnace off-gas.

The invention relates to a method of preparing a mineral melt in a cupola furnace that uses at least one plasma torch to provide heat energy to the furnace. The plasma torch uses nitrogen, carbon monoxide, carbon dioxide, or a mixture thereof as the carrier gas. The invention also relates to a cupola furnace for the preparation of the mineral melt, and the use of a plasma torch in a cupola furnace to reduce the amount of NO.sub.x and/or hydrogen in the furnace off-gas.

A metal alloy is for use at very high temperature, in particular the metal alloy can be used in a process for the manufacture of mineral wool by fiberizing a molten mineral composition. The metal alloy contains the following elements, the proportions being shown as percentage by weight of the alloy: Cr 20 to 35% Fe 10 to 25% W 2 to 10% Nb 0.5 to 2.5% Ti 0 to 1% C 0.2 to 1.2% Co less than 5% Si less than 0.9% Mn less than 0.9%
the remainder consisting of nickel and unavoidable impurities.