A method of and an arrangement for recycling mineral wool waste to mineral wool production includes at least one melting furnace for melting virgin mineral wool raw material, the melting furnace including an inlet for virgin mineral wool raw material and an outlet for molten mineral wool material, a production line connected to the outlet for molten mineral wool material for producing a mineral wool product from the molten mineral wool material. The production line includes a curing oven, a fluidized bed reactor including an exhaust gas duct, an inlet for predetermined primary fuel, an inlet for predetermined bed material, and an outlet for an ash material, the ash material including bottom ash discharged via a bottom outlet from the fluidized bed reactor or fly ash separated by a particle separator from exhaust gas in the exhaust gas duct or a mixture of the bottom ash and the fly ash.

Methods and apparatus provide for: feeding glass batch material into a plasma containment vessel in such a way that the glass batch material is dispensed as a sheet of glass batch material particles; directing one or more sources of plasma gas into the inner volume of the plasma containment vessel in such a way that the plasma gas enters the plasma containment vessel as at least one sheet of plasma gas; and applying an alternating electric field to facilitate production of a plasma plume within the inner volume of the plasma containment vessel, where the plasma plume is of dimensions sufficient to envelope the sheet of glass batch material particles, and is of sufficient thermal energy to cause the glass batch material to react and melt thereby forming substantially homogeneous, spheroid-shaped glass intermediate particles.

A method of and an arrangement for recycling mineral wool waste to mineral wool production includes at least one melting furnace for melting virgin mineral wool raw material, the melting furnace including an inlet for virgin mineral wool raw material and an outlet for molten mineral wool material, a production line connected to the outlet for molten mineral wool material for producing a mineral wool product from the molten mineral wool material. The production line includes a curing oven, a fluidized bed reactor including an exhaust gas duct, an inlet for predetermined primary fuel, an inlet for predetermined bed material, and an outlet for an ash material, the ash material including bottom ash discharged via a bottom outlet from the fluidized bed reactor or fly ash separated by a particle separator from exhaust gas in the exhaust gas duct or a mixture of the bottom ash and the fly ash.

This disclosure relates to fabrication of quartz hollow cylinder with reduced bubbles using atmospheric control. An example horizontal rotating arc furnace includes a housing, supports, and a rotary union. The housing defines an interior configured to receive silica particles and electrodes that generate a plasma arc and includes a plurality of first ports on an exterior of the housing fluidly connected to the interior and supply pipes fluidly coupled to the first ports. The supports mechanically couple the housing to a drive system to provide rotational motion to the housing. The rotary union is coupled to the housing includes second ports to fluidly connect to a vacuum supply. The second ports are fluidly connected to the first ports via the supply pipes. The horizontal rotating arc furnace is configured to apply a vacuum to the interior of the housing via the first ports when the housing is spinning.

The present invention relates to a process for preparing a mineral melt in a cupola furnace that comprises a plasma torch that heats mineral material and waste or recycled mineral material to form the melt, wherein the waste or recycled mineral 5 material is introduced into the furnace through a waste inlet located in the side wall of the furnace hot zone.