Process for confinement of waste containing at least one chemical species to be confined, by in-can vitrification in a hot metal can into which waste and a vitrification additive are added, the waste and the vitrification additive are melted to obtain a glass melt which is then cooled, characterised in that at least one oxidising agent is also added into the metal can and in that the concentration of oxidising agent(s) expressed as oxide(s) in the glass melt is between 0.1 and 20% by mass, preferably 4 and 20% by mass, even more preferably 5 and 15% by mass, and even more preferably 10 and 13% by mass of the glass melt mass.

A method of fabrication of arsenic glass, comprising forming pellets of an arsenic-containing glass-forming mixture comprising arsenic in a range between about 30 and about 50% w/w and glass forming elements, and melting the pellets by direct heating to a temperature in a range between about 950 and about 1250 C.

A method for manufacturing glass, including the steps of heat-melting a raw material for producing glass by using a melting furnace having a plurality of gas flow paths while the raw material is levitated from the melting furnace by a gas ejected from the gas flow paths, and performing cooling so as to produce glass, wherein the melting furnace includes a recess portion, at least one first gas flow path configured to eject the gas in the vertical direction into the recess portion, a plurality of second gas flow paths configured to eject the gas in the direction toward the center axis of the melting furnace into the recess portion, the raw material is heat-melted while the raw material is levitated by the gas ejected from the first gas flow path and the gas ejected from the second gas flow paths, and the molten raw material is cooled.

A method for manufacturing glass, including the steps of heat-melting a raw material for producing glass by using a melting furnace having a plurality of gas flow paths while the raw material is levitated from the melting furnace by a gas ejected from the gas flow paths, and performing cooling so as to produce glass, wherein the melting furnace includes a recess portion, at least one first gas flow path configured to eject the gas in the vertical direction into the recess portion, a plurality of second gas flow paths configured to eject the gas in the direction toward the center axis of the melting furnace into the recess portion, the raw material is heat-melted while the raw material is levitated by the gas ejected from the first gas flow path and the gas ejected from the second gas flow paths, and the molten raw material is cooled.

A method for making high optical quality multicomponent chalcogenide glasses without refractive index perturbations due to striae, phase separation or crystal formation using a sealed ampoule with chemical components enclosed inside, a two-zone furnace, a convection heating/mixing step, and multiple fining steps. Initially, the sealed ampoule is oriented vertically within the two-zone furnace and heated to melt the chemical components contained within, and a temperature gradient is created between the top zone and the bottom zone such that the bottom zone has a higher temperature. This temperature gradient causes convection currents within the viscous liquid until it is sufficiently mixed due to the convective flow. Then the temperature gradient is reversed such that the top zone now has a higher temperature and the convective flow ceases. The furnace temperatures are then reduced over a period of time, with holds at multiple temperatures for fining and cooling to form a solid glass.

A method for making high optical quality multicomponent chalcogenide glasses without refractive index perturbations due to striae, phase separation or crystal formation using a sealed ampoule with chemical components enclosed inside, a two-zone furnace, a convection heating/mixing step, and multiple fining steps. Initially, the sealed ampoule is oriented vertically within the two-zone furnace and heated to melt the chemical components contained within, and a temperature gradient is created between the top zone and the bottom zone such that the bottom zone has a higher temperature. This temperature gradient causes convection currents within the viscous liquid until it is sufficiently mixed due to the convective flow. Then the temperature gradient is reversed such that the top zone now has a higher temperature and the convective flow ceases. The furnace temperatures are then reduced over a period of time, with holds at multiple temperatures for fining and cooling to form a solid glass.

One aspect relates to a process for the preparation of a quartz glass body, including providing a silicon dioxide granulate, making a glass melt out of silicon dioxide granulate and making a quartz glass body out of at least part of the glass melt. The silicon dioxide granulate is obtained by providing and processing a silicon dioxide powder. One aspect also relates to silicon dioxide granulate, which is obtained by providing a silicon dioxide powder and processing it. One aspect further relates to a quartz glass body which is obtainable by this process. One aspect further relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing of the quartz glass body.

A method of making a transparent article includes mixing an oxygen source, a nitrogen source, a magnesium source, a silicon source and a calcium source. The oxygen source, the nitrogen source, the magnesium source, the silicon source, and the calcium source are milled and heated to form a molten oxynitride glass modified by calcium and magnesium. The molten oxynitride glass modified by calcium and magnesium is then cooled to form a transparent body having ballistic resistance with a level of performance satisfying Level IV of National Institute of Justice Standard 0108.01. Transparent articles having transparent bodies formed from the oxynitride glass are also described.

Provided is a method for manufacturing an infrared-transmissive lens having an excellent surface quality. A method for manufacturing an infrared-transmissive lens includes firing a preform of a chalcogenide glass in an inert gas atmosphere to obtain a fired body and then subjecting the fired body to hot press molding.

One aspect is an oven including a melting crucible with a crucible wall, a solids feed with an outlet, a gas inlet and a gas outlet, wherein in the melting crucible the gas inlet is arranged below the solids feed outlet and the gas outlet is arranged at the same height as or above the solids feed outlet. One aspect further relates to a process for making a quartz glass body, including providing and introducing a bulk material selected from silicon dioxide granulate and quartz glass grain into the oven and providing a gas, making a glass melt from the bulk material, and making a quartz glass body from at least a part of the glass melt. One aspect relates to a quartz glass body obtainable by this process and a light guide, an illuminant and a formed body which are each obtainable by processing the quartz glass body further.