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.

Methods and systems for removing impurities from an electrolytic salt are disclosed. After removal of impurities from the salt, the salt can be subjected to electrorefining to produce high-purity materials, for example silicon. Impurities are removed from the salt using a system that includes a first working electrode, a counter electrode, and at least one reference electrode. A second working electrode can also be utilized. The salt may be utilized in an electrorefining system, for example a system operated in a single phase or multiple phase operation to produce high-purity materials, such as solar-grade silicon.

Methods and systems for removing impurities from an electrolytic salt are disclosed. After removal of impurities from the salt, the salt can be subjected to electrorefining to produce high-purity materials, for example silicon. Impurities are removed from the salt using a system that includes a first working electrode, a counter electrode, and at least one reference electrode. A second working electrode can also be utilized. The salt may be utilized in an electrorefining system, for example a system operated in a single phase or multiple phase operation to produce high-purity materials, such as solar-grade silicon.

The invention provides chunk polycrystalline silicon having a concentration of carbon at the surface of 0.5-35 ppbw. A process for cleaning polycrystalline silicon chunks having carbon contaminations at the surface, includes a thermal treatment of the polycrystalline silicon chunks in a reactor at a temperature of 350 to 600° C., the polycrystalline silicon chunks being present in an inert gas atmosphere during the thermal treatment, and the polycrystalline silicon chunks after the thermal treatment having a concentration of carbon at the surface of 0.5-35 ppbw.

The invention provides chunk polycrystalline silicon having a concentration of carbon at the surface of 0.5-35 ppbw. A process for cleaning polycrystalline silicon chunks having carbon contaminations at the surface, includes a thermal treatment of the polycrystalline silicon chunks in a reactor at a temperature of 350 to 600° C., the polycrystalline silicon chunks being present in an inert gas atmosphere during the thermal treatment, and the polycrystalline silicon chunks after the thermal treatment having a concentration of carbon at the surface of 0.5-35 ppbw.

A method of determining a concentration of plastic or other material not dissolved by silicon etchants contaminating a silicon product comprising: obtaining a sample of the silicon product contaminated with the plastic or other material not dissolved by silicon etchants; placing the sample of the silicon product into a ultrasonic bath liquid to produce a slurry comprising the ultrasonic bath liquid, silicon dust, and the plastic or other material not dissolved by silicon etchants; filtering the slurry with a first filter to produce a cake comprising the silicon dust and the plastic or other material not dissolved by silicon etchants separated from the sample of the silicon product; and analyzing the cake to determine the concentration of plastic or other material not dissolved by silicon etchants contaminating the silicon product.

A preparation method of an ant nest like porous silicon for a lithium-ion battery comprises: (1) enabling a magnesium silicide raw material to react for 2-24 h in an ammonia gas or an atmosphere containing an ammonia gas at 600-900° C. to obtain a crude product containing porous silicon; and (2) subjecting the crude product containing porous silicon to an acid pickling treatment to obtain the ant nest like porous silicon. The preparation method has the advantages of simplicity and easiness. A large amount of porous silicon can be obtained by directly heating the magnesium silicide raw material in the ammonia gas or a mixed gas of the ammonia gas and an inert gas with a high yield.

There are disclosed energetic nanoparticle compositions and materials containing silicon and other energetic elements, and methods of manufacturing the same, including reacting silicon nanoparticles and unsaturated alkene or alkyne to form covalently bonded surface coatings passivated against surface oxidation, for combination with a fuel, explosive or oxidizer.

A production process for carbon-coated silicon material includes the steps of: a lamellar-silicon-compound production step of reacting CaSi.sub.2 with an acid to turn the CaSi.sub.2 into a lamellar silicon compound; a silicon-material production step of heating the lamellar silicon compound at 300° C. or more to turn the lamellar silicon compound into a silicon material; a coating step of coating the silicon material with carbon; and a washing step of washing the silicon material, or another silicon material undergone the coating step, with a solvent of which the relative permittivity is 5 or more.

An embodiment of the present invention provides a method for preparing a silicon-carbon-graphene composite, comprising the steps of: (step 1) adding a carbon precursor solution to silicon and performing wet grinding so as to prepare a suspension: (step 2) forming a silicon-carbon composite by spray drying the suspension; and (step 3) spray drying and heat treating a solution comprising the silicon-carbon composite and graphene oxide.