Abstract: A polycrystalline silicon crushed lump has a surface metal concentration of 15.0 pptw or less, in which a copper concentration is 0.30 pptw or less in the surface metal concentration, and a total concentration of iron and zinc is 2.00 pptw or less in the surface metal concentration, and preferably an iron concentration is 1.25 pptw or less, and a zinc concentration is 0.75 pptw or less.

Abstract: A polycrystalline silicon lump packaging body is a packaging body in which the resin bag is filled with the polycrystalline silicon lumps having a surface metal concentration of 1000 pptw or less, in which a nitrate ion amount and preferably a fluorine ion amount present inside the packaging body are each 50 ?g/L or less with respect to a filling void of the polycrystalline silicon lumps formed when the packaging body is left at 25° C. under 1 atm.

Abstract: A process for producing polycrystalline silicon, comprising: a silicon deposition step for producing silicon through a reaction between a chlorosilane compound and hydrogen; a conversion reaction step for removing hydrogen chloride contained in an exhaust gas discharged from the silicon deposition step by bringing the exhaust gas into contact with activated carbon; a separation step for separating hydrogen contained in the gas after the conversion reaction obtained from the conversion reaction step; and a recycling step for supplying hydrogen obtained from the separation step to the silicon deposition step, wherein at least one of the following conditions (1) and (2) is satisfied: (1) the gas after the conversion reaction obtained from the conversion reaction step is brought into contact with an adsorbent containing a Lewis acid compound before the separation step; and (2) hydrogen obtained from the separation step is brought into contact with an adsorbent containing a Lewis acid compound before it is supplie

Abstract: A method for producing polysilicon includes a deposition step for depositing polysilicon from raw material gas including chlorosilanes, and a heat recovery step of supplying exhaust gas generated from the deposition step in a boiler type heat recovery device provided with an exhaust gas pipe and then recovering heat. A gas temperature at an exhaust gas pipe outlet of the boiler type heat recovery device is set to 200° C. or more, and an exhaust gas flow rate at the exhaust gas pipe outlet in the boiler type heat recovery device is adjusted to 10 m/second or higher.

Abstract: A process for producing silicon comprises the steps of a reduction step [1] of depositing silicon by reacting chlorosilanes and hydrogen in a reactor under heat and discharging an exhaust gas that contains hydrogen, oligomers of silanes, and a silicon powder; a carring step [2] of carrying the exhaust gas that has been exhausted in the step [1] while keeping a temperature of the exhaust gas at not less than 105° C.; a removal step [3] of supplying the exhaust gas that has been carried in the step [2] to a filter at a temperature of not less than 105° C. and discharging the exhaust gas from the filter at a temperature of not less than 105° C. to remove the silicon powder from the exhaust gas and give a mixed gas that contains the hydrogen and the oligomers of silanes; and a separation step [4] of cooling the mixed gas that has been obtained in the step [3] to separate the hydrogen as a gas phase from the mixed gas.

Abstract: A process for producing silicon comprises the steps of a reduction step [1] of depositing silicon by reacting chlorosilanes and hydrogen in a reactor under heat and discharging an exhaust gas that contains hydrogen, oligomers of silanes, and a silicon powder; a carring step [2] of carrying the exhaust gas that has been exhausted in the step [1] while keeping a temperature of the exhaust gas at not less than 105° C.; a removal step [3] of supplying the exhaust gas that has been carried in the step [2] to a filter at a temperature of not less than 105° C. and discharging the exhaust gas from the filter at a temperature of not less than 105° C. to remove the silicon powder from the exhaust gas and give a mixed gas that contains the hydrogen and the oligomers of silanes; and a separation step [4] of cooling the mixed gas that has been obtained in the step [3] to separate the hydrogen as a gas phase from the mixed gas.

Abstract: In a reaction apparatus of the chlorosilanes for heating a reaction portion that is a section from the bottom end portion to a specified height in the carbon reaction vessel and that has an inside face to which silicon has deposited, and for reacting the chlorosilanes by making the chlorosilanes and hydrogen to come into contact with the inside face of the reaction portion, a gas penetration preventing processing for preventing the chlorosilanes supplied to the reaction vessel from penetrating a pipe wall of the non reaction portion in the reaction vessel is carried out to the inside face and/or the outside face of the non reaction portion on the side upper than the reaction portion in the reaction vessel.

Abstract: It is an object to provide a reaction apparatus of the chlorosilanes sufficiently capable of suppressing that a raw gas such as the chlorosilanes supplied into the reaction vessel penetrates a pipe wall of the reaction vessel to leak externally. In a reaction apparatus of the chlorosilanes for heating a reaction portion that is a section from the bottom end portion to a specified height in the carbon reaction vessel and that has an inside face to which silicon has deposited, and for reacting the chlorosilanes by making the chlorosilanes and hydrogen to come into contact with the inside face of the reaction portion, a gas penetration preventing processing for preventing the chlorosilanes supplied to the reaction vessel from penetrating a pipe wall of the non reaction portion in the reaction vessel is carried out to the inside face and/or the outside face of the non reaction portion on the side upper than the reaction portion in the reaction vessel.