A glass furnace includes a furnace chamber including a side wall and a bottom wall and containing a pool of glass melt having a melt level. A batch feed hopper is adjacent to the side wall of the furnace chamber to supply batch material under gravity to a bottom of the hopper. A feed opening is in the side wall of the furnace chamber and feeds batch material from the bottom of the hopper to the pool of glass melt below the melt level. A conveyor is proximate the bottom wall of the hopper and feeds the batch material from the bottom of the hopper through the feed opening and into the furnace chamber.

The invention relates to a method of making a mineral melt comprising providing a circulating combustion chamber (1) which comprises an upper zone (2), a lower zone (3) and a base zone (4), injecting particulate fuel, particulate mineral material and primary combustion gas which has optionally an oxygen level of at least 25% by volume into the upper zone of the circulating combustion chamber so that the fuel undergoes pyrolysis in the upper zone to produce char, thereby melting the particulate mineral materials to form a mineral melt and generating exhaust gases, injecting secondary combustion gas which has optionally an Oxygen level of at least 25% by volume into the lower zone of the circulating combustion chamber so that the char combusts, thereby completing combustion of the fuel, and separating the mineral melt from the hot exhaust gases so that the hot exhaust gases pass though an outlet in the circulating combustion chamber and the mineral melt collects in the base zone. The melt is optionally fiberized. The invention also relates to apparatus suitable for use in the method.

To provide a method capable of producing granules without complicating the production process even if boric acid is not used. The method for producing glass raw material granules has a step of granulating, in the presence of water, a glass raw material composition (A) which comprises from 45 to 75 mass % of silica, from 3 to 30 mass % of aluminum hydroxide and from 0.4 to 4.6 mass % of an alkali metal hydroxide.

An apparatus for charging a heating element for heating a glass melt, to restart a vitrified melting furnace, during emergency stop of the vitrified melting furnace for vitrifying radioactive waste is disclosed. The apparatus for charging a heating element into a vitrified melting furnace according to the present invention comprises a main frame, a universal joint positioned at one end of the main frame, at least one heating element binding portion rotating by being connected to the universal joint, and a gripper positioned at an end of the heating element binding portion, gripping the heating element.