A clean and low-cost approach for reusing waste residual from coal utilization and sandstone powder is disclosed. The coal waste residual may be produced from any thermal, solvent extraction or combination process. For example, a sustainable and environmentally friendly method for synthesis of beta-silicon carbide (β-SiC) using, for example, the residual of Powder River Basin (PRB) coal extraction derived from ethanol and supercritical CO2 (EtOH-SCC) extraction combined with natural sandstone.

A clean and low-cost approach for reusing waste residual from coal utilization and sandstone powder is disclosed. The coal waste residual may be produced from any thermal, solvent extraction or combination process. For example, a sustainable and environmentally friendly method for synthesis of beta-silicon carbide (β-SiC) using, for example, the residual of Powder River Basin (PRB) coal extraction derived from ethanol and supercritical CO2 (EtOH-SCC) extraction combined with natural sandstone.

The present disclosure provide a method for producing large granular high-purity α-phase silicon carbide powders using a silicon dioxide/carbon composite, the method including: producing a gel in which the carbonaceous compound is dispersed in a silicon dioxide network structure through a sol-gel process using starting materials including liquid phase silicon containing compounds and liquid phase carbonaceous compounds; subjecting the gel to first heat treatment to thermally decompose the carbon carbonaceous compound, thereby producing a silicon dioxide/carbon composite including nano-sized carbon particles; and subjecting the silicon dioxide/carbon composite to second heat treatment at a higher temperature than that of the first heat treatment to obtain large granular high-purity α-phase silicon carbide powders.

The present disclosure provide a method for producing large granular high-purity α-phase silicon carbide powders using a silicon dioxide/carbon composite, the method including: producing a gel in which the carbonaceous compound is dispersed in a silicon dioxide network structure through a sol-gel process using starting materials including liquid phase silicon containing compounds and liquid phase carbonaceous compounds; subjecting the gel to first heat treatment to thermally decompose the carbon carbonaceous compound, thereby producing a silicon dioxide/carbon composite including nano-sized carbon particles; and subjecting the silicon dioxide/carbon composite to second heat treatment at a higher temperature than that of the first heat treatment to obtain large granular high-purity α-phase silicon carbide powders.

The present application provides a method, a equipment and a system for producing a silicon-containing products by using a silicon sludge which is produced by a diamond wire cutting silicon material. The method of the present application mainly utilizes a high oxide layer on the surface of a silicon waste particle produced during diamond wire cutting. The characteristics are such that the surface oxide disproportionates with adjacent internal elemental silicon to form silicon monoxide to be removed in a vapor to achieve a physical chemical reaction with a metal, a halogen gas, a hydrogen halide gas or hydrogen to form a high value-added silicon-containing products. The process realizes the large-scale, high-efficiency, energy-saving, continuous and low-cost complete recycling of diamond-wire cutting silicon waste.

The present application provides a method, a equipment and a system for producing a silicon-containing products by using a silicon sludge which is produced by a diamond wire cutting silicon material. The method of the present application mainly utilizes a high oxide layer on the surface of a silicon waste particle produced during diamond wire cutting. The characteristics are such that the surface oxide disproportionates with adjacent internal elemental silicon to form silicon monoxide to be removed in a vapor to achieve a physical chemical reaction with a metal, a halogen gas, a hydrogen halide gas or hydrogen to form a high value-added silicon-containing products. The process realizes the large-scale, high-efficiency, energy-saving, continuous and low-cost complete recycling of diamond-wire cutting silicon waste.

Described are methods of making silicon-carbon nanocomposite materials. Also provided are silicon-carbon nanocomposite materials, which are made using the methods of the present disclosure. Also provided are electrode materials and ion-conducting batteries including the silicon-carbon nanocomposite materials of the present disclosure.

Described are methods of making silicon-carbon nanocomposite materials. Also provided are silicon-carbon nanocomposite materials, which are made using the methods of the present disclosure. Also provided are electrode materials and ion-conducting batteries including the silicon-carbon nanocomposite materials of the present disclosure.

A method of purifying silicon carbide powder includes: providing a container with a surface coated by a nitrogen-removal metal layer, wherein the nitrogen-removal metal layer is tantalum, niobium, tungsten, or a combination thereof; putting a silicon carbide powder into the container to contact the nitrogen-removal metal layer; and heating the silicon carbide powder under an inert gas at a pressure of 400 torr to 760 torr at 1700° C. to 2300° C. for 2 to 10 hours, thereby reducing the nitrogen content of the silicon carbide powder.

A method of purifying silicon carbide powder includes: providing a container with a surface coated by a nitrogen-removal metal layer, wherein the nitrogen-removal metal layer is tantalum, niobium, tungsten, or a combination thereof; putting a silicon carbide powder into the container to contact the nitrogen-removal metal layer; and heating the silicon carbide powder under an inert gas at a pressure of 400 torr to 760 torr at 1700° C. to 2300° C. for 2 to 10 hours, thereby reducing the nitrogen content of the silicon carbide powder.