A method for removing phosphorus and boron impurities in an industrial silicon melt by secondary refining is provided. According to the present disclosure, inorganic zinc chloride is adopted as an impurity removal medium and is quickly decomposed into zinc and chloride ions at high temperatures; the phosphorus and boron impurities can react with the zinc and chloride ions to yield low-melting and high-melting compounds during contact with a silicon melt, the low-melting compounds volatilize and escape from the industrial silicon melt at the high temperature of the secondary refining. The high-melting compounds are segregated at the grain boundary along with silicon solidification and removed by crushing and pickling, or sink to the very bottom of the silicon melt and are removed by cutting off a deposition layer at a bottom of a silicon ingot after the silicon melt is solidified.

A method for removing phosphorus and boron impurities in an industrial silicon melt by secondary refining is provided. According to the present disclosure, inorganic zinc chloride is adopted as an impurity removal medium and is quickly decomposed into zinc and chloride ions at high temperatures; the phosphorus and boron impurities can react with the zinc and chloride ions to yield low-melting and high-melting compounds during contact with a silicon melt, the low-melting compounds volatilize and escape from the industrial silicon melt at the high temperature of the secondary refining. The high-melting compounds are segregated at the grain boundary along with silicon solidification and removed by crushing and pickling, or sink to the very bottom of the silicon melt and are removed by cutting off a deposition layer at a bottom of a silicon ingot after the silicon melt is solidified.

A method for removing phosphorus and boron impurities in an industrial silicon melt by secondary refining is provided. According to the present disclosure, inorganic zinc chloride is adopted as an impurity removal medium and is quickly decomposed into zinc and chloride ions at high temperatures; the phosphorus and boron impurities can react with the zinc and chloride ions to yield low-melting and high-melting compounds during contact with a silicon melt, the low-melting compounds volatilize and escape from the industrial silicon melt at the high temperature of the secondary refining. The high-melting compounds are segregated at the grain boundary along with silicon solidification and removed by crushing and pickling, or sink to the very bottom of the silicon melt and are removed by cutting off a deposition layer at a bottom of a silicon ingot after the silicon melt is solidified.

A method for removing phosphorus and boron impurities in an industrial silicon melt by secondary refining is provided. According to the present disclosure, inorganic zinc chloride is adopted as an impurity removal medium and is quickly decomposed into zinc and chloride ions at high temperatures; the phosphorus and boron impurities can react with the zinc and chloride ions to yield low-melting and high-melting compounds during contact with a silicon melt, the low-melting compounds volatilize and escape from the industrial silicon melt at the high temperature of the secondary refining. The high-melting compounds are segregated at the grain boundary along with silicon solidification and removed by crushing and pickling, or sink to the very bottom of the silicon melt and are removed by cutting off a deposition layer at a bottom of a silicon ingot after the silicon melt is solidified.

A novel bulk form of 4H-Si, a crystalline allotrope of silicon and a novel method of manufacture. The novel material consists of highly oriented microcrystals of silicon in the 4H structure with no disordered material. The 4H-Si is derived from heating a second novel material Si.sub.24 under proper conditions. The allotrope of silicon is produced as bulk, microcrystalline agglomerates.

A novel bulk form of 4H-Si, a crystalline allotrope of silicon and a novel method of manufacture. The novel material consists of highly oriented microcrystals of silicon in the 4H structure with no disordered material. The 4H-Si is derived from heating a second novel material Si.sub.24 under proper conditions. The allotrope of silicon is produced as bulk, microcrystalline agglomerates.

A clean and high-purity polycrystalline silicon mass having a small content of chromium, iron, nickel, copper, and cobalt in total, which are heavy metal impurities that reduce the quality of single-crystal silicon, can be obtained from a silicon rod by before crushing a polycrystalline silicon rod, removing at least 70 mm of a polycrystalline silicon portion from the electrode side end of the polycrystalline silicon rod extracted to the outside of a reactor is provided. Thereby, the polycrystalline silicon portion in which the total of the chromium, iron, nickel, copper, and cobalt concentrations in a bulk is not less than 150 ppta can be removed.

A clean and high-purity polycrystalline silicon mass having a small content of chromium, iron, nickel, copper, and cobalt in total, which are heavy metal impurities that reduce the quality of single-crystal silicon, can be obtained from a silicon rod by before crushing a polycrystalline silicon rod, removing at least 70 mm of a polycrystalline silicon portion from the electrode side end of the polycrystalline silicon rod extracted to the outside of a reactor is provided. Thereby, the polycrystalline silicon portion in which the total of the chromium, iron, nickel, copper, and cobalt concentrations in a bulk is not less than 150 ppta can be removed.

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

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