A porous silicon manufacturing method according to the present invention comprises the steps of: pretreating a silicon precursor and a heat dispersant; and conducting a thermal reduction reaction between the heat dispersant-pretreated silicon precursor and a metal reducing agent by using a rotary reaction chamber. When porous silicon manufactured by the manufacturing method is contained in a secondary battery anode active material and used in secondary batteries, the batteries exhibit high capacity and long lifespan characteristics. The present invention relates to a method for manufacturing porous silicon and a method for manufacturing a secondary battery anode active material containing the porous silicon manufactured thereby, with the aim of solving the problems with silicon materials under development for anode active materials for lithium secondary batteries, including excessive volume expansion during charge/discharge and resultant electrode fracture and lifespan shortening.

A super hard polycrystalline construction is disclosed as comprising a first region comprising a body of thermally stable polycrystalline diamond material comprising a plurality of intergrown grains of diamond material; a second region forming a substrate to the first region; and a third region interposed between the first and second regions. The third region extends across a surface of the second region along an interface. The interface comprises at least a portion having an uneven topology, and the third region comprises a diamond composite material including a first phase comprising a plurality of non-intergrown super hard grains, said super hard grains comprising diamond grains; and a matrix material. The superhard material and matrix material of the third region form a diamond composite material which is more acid resistant than polycrystalline diamond material having a binder-catalyst phase comprising cobalt, and/or more acid resistant than cemented tungsten carbide material.

A super hard polycrystalline construction is disclosed as comprising a first region comprising a body of thermally stable polycrystalline diamond material comprising a plurality of intergrown grains of diamond material; a second region forming a substrate to the first region; and a third region interposed between the first and second regions. The third region extends across a surface of the second region along an interface. The interface comprises at least a portion having an uneven topology, and the third region comprises a diamond composite material including a first phase comprising a plurality of non-intergrown super hard grains, said super hard grains comprising diamond grains; and a matrix material. The superhard material and matrix material of the third region form a diamond composite material which is more acid resistant than polycrystalline diamond material having a binder-catalyst phase comprising cobalt, and/or more acid resistant than cemented tungsten carbide material.

A method for forming a porous silicon material can include forming a mixture of silicon, carbon, and an etchant element, solidifying the mixture, removing the etchant element to form pores within the silicon material. The porous silicon material can include a distribution of pores with an average pore diameter between about 10 nm and 500 nm, wherein the silicon particle comprises a silicon carbon composite comprising 1-5% carbon by mass, 1-5% oxygen by mass, and 90-98% silicon by mass.

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.

An apparatus and a process for the production of high purity silicon from silica containing material such as quartz or quartzite, using a vacuum electric arc furnace, are disclosed.

An apparatus and a process for the production of high purity silicon from silica containing material such as quartz or quartzite, using a vacuum electric arc furnace, are disclosed.

Silicon is produced by magnesiothermic reduction of silicon dioxide, wherein to achieve magnesiothermic reduction a reactant mixture is employed which contains silicon dioxide (SiO.sub.2) and magnesium (Mg) and, as moderators, magnesium oxide (MgO) and silicon (Si), and optionally further moderators.

Silicon is produced by magnesiothermic reduction of silicon dioxide, wherein to achieve magnesiothermic reduction a reactant mixture is employed which contains silicon dioxide (SiO.sub.2) and magnesium (Mg) and, as moderators, magnesium oxide (MgO) and silicon (Si), and optionally further moderators.