The present disclosure discloses a lithium disilicate glass-ceramic with high strength and high transparency and a preparation method and use thereof. A raw material composition of the lithium disilicate glass-ceramic comprises: 63-75 wt % of SiO.sub.2, 13-18 wt % of Li.sub.2O, 1-6 wt % of Al.sub.2O.sub.3, 1-10 wt % of K.sub.2O, 2-6 wt % of P.sub.2O.sub.5, 0-4 wt % of an additive and 0-10 wt % of a colorant; a main crystal phase of the lithium disilicate glass-ceramic is lithium disilicate crystals, and an impurity phase of the lithium disilicate glass-ceramic is any one or a combination of at least two selected from the group consisting of lithium metasilicate, lithium phosphate and quartz; the lithium disilicate crystal has a size larger than 700 nm and a length-diameter ratio not less than 3.

The present disclosure discloses a lithium disilicate glass-ceramic with high strength and high transparency and a preparation method and use thereof. A raw material composition of the lithium disilicate glass-ceramic comprises: 63-75 wt % of SiO.sub.2, 13-18 wt % of Li.sub.2O, 1-6 wt % of Al.sub.2O.sub.3, 1-10 wt % of K.sub.2O, 2-6 wt % of P.sub.2O.sub.5, 0-4 wt % of an additive and 0-10 wt % of a colorant; a main crystal phase of the lithium disilicate glass-ceramic is lithium disilicate crystals, and an impurity phase of the lithium disilicate glass-ceramic is any one or a combination of at least two selected from the group consisting of lithium metasilicate, lithium phosphate and quartz; the lithium disilicate crystal has a size larger than 700 nm and a length-diameter ratio not less than 3.

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.

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.

To appropriately manufacture a semiconductor device. A glass substrate is a glass substrate for manufacturing the semiconductor device. In a case in which one surface is directed downward in a vertical direction, and a first position, a second position, and a third position on the one surface on an outer side in a radial direction with respect to a center point of the glass substrate are supported by supporting members, a lowest point as a position where a height in the vertical direction is the lowest on other surface is positioned in a circular central region on an inner side in the radial direction with respect to the first position, the second position, and the third position when viewed from the vertical direction, a center of the central region is a center point of the glass substrate, and a diameter of the central region has a length of ? of a diameter of the glass substrate.

To appropriately manufacture a semiconductor device. A glass substrate is a glass substrate for manufacturing the semiconductor device. In a case in which one surface is directed downward in a vertical direction, and a first position, a second position, and a third position on the one surface on an outer side in a radial direction with respect to a center point of the glass substrate are supported by supporting members, a lowest point as a position where a height in the vertical direction is the lowest on other surface is positioned in a circular central region on an inner side in the radial direction with respect to the first position, the second position, and the third position when viewed from the vertical direction, a center of the central region is a center point of the glass substrate, and a diameter of the central region has a length of ? of a diameter of the glass substrate.

The invention relates to a smoothing tool (3) configured for smoothing glass frit in a radioactive environment, in an induction-melting cold crucible. Smoothing tool (3) comprising a rod (30), a grid (50) configured to be in contact with glass frit (7) to be smoothed, and at least one vibrator (37, 55, 56) configured to make the grid (50) vibrate. The grid (50) is mechanically connected to the rod (30).

Provided is a glass production method with which oxidation can be suppressed and productivity can be increased. A glass production method according to the present invention includes the steps of: turning a raw material 6 placed in a container 1 into a melt 11; homogenizing the melt 11; removing a gas from the melt 11, wherein at least one of the step of turning the raw material 6 into the melt 11 and the step of homogenizing the melt 11 is performed in an atmosphere of an inert gas or a reducing gas, and in the step of the removing the gas from the melt 11, the inert gas or the reducing gas is removed by setting the temperature of the melt 11 to be lower than the temperature in the step of homogenizing the melt 11.

The present disclosure provides an apparatus for eliminating a heterogeneous glass present in the top surface of a molten glass effectively, and a melting furnace and a glass manufacturing apparatus comprising the same. The apparatus for eliminating a heterogeneous glass according to one aspect of the present disclosure comprises a storage bath having an inlet and an outlet to receive a molten glass fed into the inlet and to discharge the received molten glass through the outlet, and an evacuating opening formed on the top of the storage bath, the evacuating opening allowing the received molten glass to overflow; a first gate being mounted close to the outlet of the storage bath to adjust an open area, thereby controlling the flow rate of the molten glass to be discharged through the outlet; and a second gate being mounted close to the inlet of the storage bath to control the height of the molten glass received in the storage bath at the section in which the evacuating opening is formed.

The present disclosure provides an apparatus for eliminating a heterogeneous glass present in the top surface of a molten glass effectively, and a melting furnace and a glass manufacturing apparatus comprising the same. The apparatus for eliminating a heterogeneous glass according to one aspect of the present disclosure comprises a storage bath having an inlet and an outlet to receive a molten glass fed into the inlet and to discharge the received molten glass through the outlet, and an evacuating opening formed on the top of the storage bath, the evacuating opening allowing the received molten glass to overflow; a first gate being mounted close to the outlet of the storage bath to adjust an open area, thereby controlling the flow rate of the molten glass to be discharged through the outlet; and a second gate being mounted close to the inlet of the storage bath to control the height of the molten glass received in the storage bath at the section in which the evacuating opening is formed.