Silicon particles for active materials and electro-chemical cells are provided. The active materials comprising silicon particles described herein can be utilized as an electrode material for a battery. In certain embodiments, the composite material includes greater than 0% and less than about 90% by weight silicon particles, the silicon particles having an average particle size between about 10 nm and about 40 μm, wherein the silicon particles have surface coatings comprising silicon carbide or a mixture of carbon and silicon carbide, and greater than 0% and less than about 90% by weight of one or more types of carbon phases, wherein at least one of the one or more types of carbon phases is a substantially continuous phase.

A process for manufacturing SiC wherein the emissions of polluting gases are minimized, by reduction of silicon oxide by an excess of carbon, the process including electrically heating a resistor at the heart of a mixture of raw materials consisting of a carbon-based source chosen from petroleum cokes and a source of silicon, especially a silica having a purity of greater than 95% of SiO.sub.2, in order to give rise, at a temperature above 1500° C., to the simplified reaction: SiO.sub.2+3C=SiC+2CO (1), wherein the carbon-based source first undergoes a treatment for removing the contained hydrogen, so that its elemental hydrogen content (EHWC) is less than 2% by weight.

A process for manufacturing SiC wherein the emissions of polluting gases are minimized, by reduction of silicon oxide by an excess of carbon, the process including electrically heating a resistor at the heart of a mixture of raw materials consisting of a carbon-based source chosen from petroleum cokes and a source of silicon, especially a silica having a purity of greater than 95% of SiO.sub.2, in order to give rise, at a temperature above 1500° C., to the simplified reaction: SiO.sub.2+3C=SiC+2CO (1), wherein the carbon-based source first undergoes a treatment for removing the contained hydrogen, so that its elemental hydrogen content (EHWC) is less than 2% by weight.

The invention discloses a method for producing silicon carbide from waste circuit board cracking residue, belongs to the field of comprehensive utilization of waste circuit board cracking products, and particularly relates to a method for high-valued utilization of non-metal components in waste circuit board cracking residue. The method mainly comprises the following steps: rolling and crushing, vibration sorting, ultrafine pulverization and electro-separation, quantitative batching, microwave sintering and discharging and grading. Compared with the prior art, rolling crushing is adopted to replace traditional shearing crushing, microwave sintering is adopted to replace a traditional Acheson smelting furnace, the effects of being easy to operate, saving energy and reducing consumption are achieved, the production efficiency is greatly improved, and the production cost is reduced. A brand-new method for obtaining high-purity silicon carbide by partially replacing anthracite and quartz sand with cracked coke and silicon dioxide in waste circuit board light plates or epoxy resin cracking residues is adopted, and high-value utilization of waste resources is achieved. The method has the characteristics of simple and feasible process, low manufacturing cost and wide adaptability, and is beneficial to improving the economic benefit and social benefit of enterprise production.

Porous three-dimensional networks of polyimide and porous three-dimensional networks of carbon and methods of their manufacture are described. For example, polyimide aerogels are prepared by mixing a dianhydride and a diisocyanate in a solvent comprising a pyrrolidone and acetonitrile at room temperature to form a sol-gel material and supercritically drying the sol-gel material to form the polyimide aerogel. Porous three-dimensional polyimide networks, such as polyimide aerogels, may also exhibit a fibrous morphology. Having a porous three-dimensional polyimide network undergo an additional step of pyrolysis may result in the three dimensional network being converted to a purely carbon skeleton, yielding a porous three-dimensional carbon network. The carbon network, having been derived from a fibrous polyimide network, may also exhibit a fibrous morphology.

A silicon carbide powder which, when used as a raw material in a sublimation recrystallization method, enables improvement in productivity of a silicon carbide single crystal by exhibiting a high sublimation rate and allowing a small amount of silicon carbide to remain without being sublimated, and enables an increase in size of the silicon carbide single crystal (for example, a single crystal wafer). The silicon carbide powder has a Blaine specific surface area of from 250 cm.sup.2/g to 1,000 cm.sup.2/g and a ratio of a silicon carbide powder having a particle size of more than 0.70 mm and 3.00 mm or less of 50 vol % or more with respect to a total amount of the silicon carbide powder. When a silicon carbide powder accommodated in a crucible is heated to be sublimated, a silicon carbide single crystal is formed on a seed crystal provided on an undersurface of a lid.

Silicon particles for active materials and electro-chemical cells are provided. The active materials comprising silicon particles described herein can be utilized as an electrode material for a battery. In certain embodiments, the composite material includes greater than 0% and less than about 90% by weight silicon particles, the silicon particles having an average particle size between about 10 nm and about 40 μm, wherein the silicon particles have surface coatings comprising silicon carbide or a mixture of carbon and silicon carbide, and greater than 0% and less than about 90% by weight of one or more types of carbon phases, wherein at least one of the one or more types of carbon phases is a substantially continuous phase.

Three-dimensional nanoporous aerogels and suitable preparation methods are provided. Nanoporous aerogels may include a carbide material such as a silicon carbide, a metal carbide, or a metalloid carbide. Elemental (e.g., metallic or metalloid) aerogels may also be produced. In some embodiments, a cross-linked aerogel having a conformal coating on a sol-gel material is processed to form a carbide aerogel, metal aerogel, or metalloid aerogel. A three-dimensional nanoporous network may include a free radical initiator that reacts with a cross-linking agent to form the cross-linked aerogel. The cross-linked aerogel may be chemically aromatized and chemically carbonized to form a carbon-coated aerogel. The carbon-coated aerogel may be suitably processed to undergo a carbothermal reduction, yielding an aerogel where oxygen is chemically extracted. Residual carbon remaining on the surface of the aerogel may be removed via an appropriate cleaning treatment.

Three-dimensional nanoporous aerogels and suitable preparation methods are provided. Nanoporous aerogels may include a carbide material such as a silicon carbide, a metal carbide, or a metalloid carbide. Elemental (e.g., metallic or metalloid) aerogels may also be produced. In some embodiments, a cross-linked aerogel having a conformal coating on a sol-gel material is processed to form a carbide aerogel, metal aerogel, or metalloid aerogel. A three-dimensional nanoporous network may include a free radical initiator that reacts with a cross-linking agent to form the cross-linked aerogel. The cross-linked aerogel may be chemically aromatized and chemically carbonized to form a carbon-coated aerogel. The carbon-coated aerogel may be suitably processed to undergo a carbothermal reduction, yielding an aerogel where oxygen is chemically extracted. Residual carbon remaining on the surface of the aerogel may be removed via an appropriate cleaning treatment.

A manufacturing apparatus of carbide of the present disclosure includes a tank, a lid, a molten salt crucible, an electrode assembly, an air intake device and a heating device. The lid is connected to the tank to jointly delimit a compartment. The molten salt crucible is disposed in the compartment for containing a salt. The electrode assembly includes a working electrode and a counter electrode. An end of the working electrode and an end of the counter electrode both contact the salt in the molten salt crucible, and the end of the working electrode contacting the salt is for fixing a reactant tablet. The air intake device is configured to exchange the air in the compartment. The heating device is configured to heat the compartment.