A production method for producing an oxygen sensor, includes spinning a precursor consisting of a salt of at least one metal chosen from Sc, Y, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Yb, Sr, Ba, Mn, Co, Mg, and Ga, a solvent, and a macromolecular polymer to produce nanofibers of the precursor containing the salt of the metal. The method further includes calcining the nanofibers of the precursor at a temperature ranging from 550 C. to 650 C. for 2 to 4 hours, and making a solid electrolyte material composed of the nanofibers obtained from the calcining. The resulting solid electrolyte material constitutes a part of the oxygen sensor.

A metal suboxide having a specific surface area of greater than or equal to about 1.5 m.sup.2/g is prepared by preparing a metal suboxide precursor, and heat-treating the metal suboxide precursor.

A metal suboxide having a specific surface area of greater than or equal to about 1.5 m.sup.2/g is prepared by preparing a metal suboxide precursor, and heat-treating the metal suboxide precursor.

A recirculated-suspension pre-calciner system is disclosed, comprising: a vortex cyclone dust collecting equipment including a plurality of devices, wherein a top device of the vortex cyclone dust collecting equipment is used as a feed system; a vertical combustion kiln; a blower; and a powder purge system, wherein powders in the feed system fall into the vortex cyclone dust collecting equipment and pass through a plurality of the devices to mix and exchange heat with flue gas comprising CO.sub.2, generating calcination reaction and releasing CO2 into the flue gas. and the steam is separated and transported to the feed system by the blower and acts as a carrier gas of powders.

A recirculated-suspension pre-calciner system is disclosed, comprising: a vortex cyclone dust collecting equipment including a plurality of devices, wherein a top device of the vortex cyclone dust collecting equipment is used as a feed system; a vertical combustion kiln; a blower; and a powder purge system, wherein powders in the feed system fall into the vortex cyclone dust collecting equipment and pass through a plurality of the devices to mix and exchange heat with flue gas comprising CO.sub.2, generating calcination reaction and releasing CO2 into the flue gas. and the steam is separated and transported to the feed system by the blower and acts as a carrier gas of powders.

A method includes acquiring a three-dimensional printed template created using an additive manufacturing technique, infilling the template with an aerogel precursor solution, allowing formation of a sol-gel, and converting the sol-gel to an aerogel.

A method includes acquiring a three-dimensional printed template created using an additive manufacturing technique, infilling the template with an aerogel precursor solution, allowing formation of a sol-gel, and converting the sol-gel to an aerogel.

A method for preparing mesoporous copper oxide (CuO) includes providing a copper composition including copper (Cu), phenanthroline, and a Schiff base, combining the copper composition with a sodium salt to provide a salt mixture, and calcining the salt mixture to provide the mesoporous CuO. The mesoporous copper oxide has an ordered structure and a diameter ranging from about 0.5 m to about 3 m.

There are provided processes for treating red mud. For example, the processes can comprise leaching red mud with HCl so as to obtain a leachate comprising ions of a first metal (for example aluminum) and a solid, and separating said solid from said leachate. Several other metals can be extracted from the leachate (Fe, Ni, Co, Mg, rare earth elements, rare metals, etc.). Various other components can be extracted from solid such as TiO.sub.2, SiO.sub.2 etc.

There are provided processes for treating red mud. For example, the processes can comprise leaching red mud with HCl so as to obtain a leachate comprising ions of a first metal (for example aluminum) and a solid, and separating said solid from said leachate. Several other metals can be extracted from the leachate (Fe, Ni, Co, Mg, rare earth elements, rare metals, etc.). Various other components can be extracted from solid such as TiO.sub.2, SiO.sub.2 etc.