In a method for recovering active metals of a lithium secondary battery according to an embodiment, a cathode active material mixture is collected from the cathode of the lithium secondary battery, the cathode active material mixture is reduced by a reducing reaction to prepare a preliminary precursor mixture, an aqueous lithium precursor solution is formed from the preliminary precursor mixture, and an aluminum-containing material is removed from the aqueous lithium precursor solution with an aluminum removing resin.

A method of preparing an alumina catalyst including: performing primary calcination of an alumina precursor at a primary calcination temperature to form a mixed-phase alumina including 1% to 15% by weight of alpha-alumina, 60% to 95% by weight of theta-alumina, and 4% to 25% by weight of delta-alumina; steam-treating the mixed-phase alumina with water vapor at a steam-treating temperature lower than the primary calcination temperature to form activated mixed-phase alumina; and performing secondary calcination of the activated mixed-phase alumina at a secondary calcination temperature higher than the steam treatment temperature and lower than the primary calcination temperature after step S2. An alumina catalyst prepared using the method, and a method of preparing propylene using the alumina catalyst.

A method of preparing an alumina catalyst including: performing primary calcination of an alumina precursor at a primary calcination temperature to form a mixed-phase alumina including 1% to 15% by weight of alpha-alumina, 60% to 95% by weight of theta-alumina, and 4% to 25% by weight of delta-alumina; steam-treating the mixed-phase alumina with water vapor at a steam-treating temperature lower than the primary calcination temperature to form activated mixed-phase alumina; and performing secondary calcination of the activated mixed-phase alumina at a secondary calcination temperature higher than the steam treatment temperature and lower than the primary calcination temperature after step S2. An alumina catalyst prepared using the method, and a method of preparing propylene using the alumina catalyst.

Provided is a solid electrolyte sheet capable of increasing the adhesiveness to the electrode layer and thus achieving an excellent discharge capacity. A solid electrolyte sheet 10 in which a second solid electrolyte layer 2 is formed on at least one of both surfaces of a first solid electrolyte layer 1, the second solid electrolyte layer 2 being a porous solid electrolyte layer.

Provided is a solid electrolyte sheet capable of increasing the adhesiveness to the electrode layer and thus achieving an excellent discharge capacity. A solid electrolyte sheet 10 in which a second solid electrolyte layer 2 is formed on at least one of both surfaces of a first solid electrolyte layer 1, the second solid electrolyte layer 2 being a porous solid electrolyte layer.

The invention provides highly reactive nano-sized alumina particle compositions, including alumina compositions with a BET surface areas on the order of 2000 m.sup.2/g. Also disclosed are impregnated alumina supports comprising materials that are metal oxides or carbonates. Methods for the synthesis and fabrication of these compositions are provided, along methods for the use of these compositions as sorbents.

The invention provides highly reactive nano-sized alumina particle compositions, including alumina compositions with a BET surface areas on the order of 2000 m.sup.2/g. Also disclosed are impregnated alumina supports comprising materials that are metal oxides or carbonates. Methods for the synthesis and fabrication of these compositions are provided, along methods for the use of these compositions as sorbents.

The present disclosure discloses a process for producing microcrystalline alpha-alumina by microwave calcination, which relates to the production process of calcined alumina. The product of the present disclosure has stable quality. The yield of the process of the present disclosure is higher than that of the traditional kiln production method. The energy consumption during the preparation of alpha-alumina is greatly reduced, and the zero emission of harmful gases is realized.

A furnace may include a furnace muffle that can accommodate relatively larger workpieces than other furnaces. The furnace muffle may include a cover that includes one or more sets of plates. The plates may be configured to prevent sag during extended runtimes while still enabling the furnace to reach a temperature (e.g., a temperature between 1590° C. and 1650° C.) for sintering a workpiece. In some examples, the cover may include a first set of plates of a first material (e.g., a first alumina refractory material) and a second set of plates of a second material (e.g., a second alumina refractory material). The second material may have greater thermal conductivity than the first material. Accordingly, plates of the second set may be located in higher temperature zones of the furnace to enable efficient heat transfer from heater elements through the furnace muffle to a contact plate where a workpiece is heated.

A furnace may include a furnace muffle that can accommodate relatively larger workpieces than other furnaces. The furnace muffle may include a cover that includes one or more sets of plates. The plates may be configured to prevent sag during extended runtimes while still enabling the furnace to reach a temperature (e.g., a temperature between 1590° C. and 1650° C.) for sintering a workpiece. In some examples, the cover may include a first set of plates of a first material (e.g., a first alumina refractory material) and a second set of plates of a second material (e.g., a second alumina refractory material). The second material may have greater thermal conductivity than the first material. Accordingly, plates of the second set may be located in higher temperature zones of the furnace to enable efficient heat transfer from heater elements through the furnace muffle to a contact plate where a workpiece is heated.