Provided is a member for optical glass manufacturing apparatus. The member is used for optical glass manufacturing apparatus and exposed to a gas containing a halogen element in a high temperature environment of 1100° C. or higher. The member includes dense ceramics containing silicon nitride as a main component, and a porosity of a surface layer of the member is smaller than a porosity of the inside of the member.

The present disclosure relates to a porous ceramic media that may include a chemical composition, a phase composition, a total open porosity content of at least about 10 vol. % and not greater than about 70 vol. % as a percentage of the total volume of the ceramic media, and a nitric acid resistance parameter of not greater than about 500 ppm. The chemical composition for the porous ceramic media may include SiO.sub.2, Al.sub.2O.sub.3, an alkali component and a secondary metal oxide component selected from the group consisting of an Fe oxide, a Ti oxide, a Ca oxide, a Mg oxide and combinations thereof. The phase composition may include an amorphous silicate, quartz and mullite.

Per- and polyfluoroalkyl substances (PFAS) are destroyed by oxidation in supercritical conditions. PFAS in water is concentrated in a reverse osmosis step and salt from the resulting solution is removed in supercritical conditions prior to destruction of PFAS in supercritical conditions.

A member for optical glass production apparatus is a member exposed to a gas containing a halogen element in a high temperature environment; the member includes a first member (4) directly or indirectly supporting an optical glass (10) and a second member (5) supporting the first member (4).

An yttrium oxide-based sintered body contains yttrium oxide as a main constituent and 0.1 wt % or more and 5.0 wt % or less of zirconium on a ZrO.sub.2 basis. Such an yttrium oxide-based sintered body made with yttrium oxide and a certain amount of zirconium oxide therein is highly resistant to corrosive chemicals while maintaining superior resistance to plasma and corrosive gases.

A refractory object may include a zircon body that may include at least about 0.1 wt. % and not greater than about 5.5 wt. % of an Al.sub.2O.sub.3 containing component for a total weight of the zircon body. The zircon body may further include at least about 25 wt. % and not greater than about 35 wt. % of a SiO.sub.2 component for a total weight of the zircon body.

A method for improving the insulating character/and or penetration resistance of a surface comprising lining a surface of a lime kiln, a cement kiln, a roasting kiln, a thermal oxidizer, or a fluidized bed reactor that is subject to wear by an alkali environment and/or an alkaline environment with a refractory composition comprising a refractory aggregate consisting essentially of a calcium hexa aluminate clinker having the formula CA.sub.6, wherein C is equal to calcium oxide, wherein A is equal to aluminum oxide, and wherein the hexa aluminate clinker has from zero to less than about fifty weight percent C.sub.12A.sub.7, and wherein greater than 98 weight percent of the calcium hexa aluminate clinker having a particle size ranging from −20 microns to +3 millimeters, for forming a liner of the surface.

A sintered body of the present invention contains yttrium oxyfluoride. The yttrium oxyfluoride is preferably YOF and/or Y.sub.5O.sub.4F.sub.7. The sintered body of the present invention preferably contains 50% by mass or more of yttrium oxyfluoride. The sintered body of the present invention has a relative density of preferably 70% or more and an open porosity of preferably 10% or less. Furthermore, the sintered body of the present invention has a three-point bending strength of preferably 10 MPa or more and 300 MPa or less.

A refractory object can include at least 10 wt % Al.sub.2O.sub.3. Further, the refractory object may contain less than approximately 6 wt % SiO.sub.2 or may include a dopant that includes an oxide of Ti, Mg, Ta, Nb, or any combination thereof. In an embodiment, at least approximately 1% of the Al.sub.2O.sub.3 in the refractory object can be provided as reactive Al.sub.2O.sub.3. In another embodiment, the refractory object may have a density of at least approximately 3.55 g/cc, a corrosion rate of no greater than approximately 2.69 mm/year, or any combination of the foregoing. In a particular embodiment, the refractory object can be used to form an Al—Si—Mg glass sheet. In an embodiment, the refractory object may be formed by a process using a compound of Ti, Mg, Ta, Nb, or any combination thereof.

Provided are a corrosion-resistant member in which, in a case where the corrosion-resistant member is used as a member for an electrostatic chuck, an adsorption force of the electrostatic chuck can be made to be strong when an electric field is applied and a residual adsorption force of the electrostatic chuck can be made to be weak when the application of the electric field is stopped; a member for an electrostatic chuck; and a process for producing a corrosion-resistant member. The corrosion-resistant member includes an oxide which includes samarium and aluminum and has a perovskite type structure. The member for an electrostatic chuck includes the corrosion-resistant member according to the present invention. The process for producing a corrosion-resistant member according to the present invention includes: a step of mixing aluminum oxide powder and samarium oxide powder with a solvent to prepare a slurry including the aluminum oxide powder and the samarium oxide powder; a step of drying the slurry to prepare a mixed powder including the aluminum powder and the samarium oxide powder, and molding the mixed powder to prepare a green body; and a step of calcinating the green body to prepare a sintered body.