A process for purifying low-purity metallurgical grade silicon, containing at least one contaminant and obtaining a higher-purity solid polycrystalline silicon is provided. The process includes containing a melt of low-purity metallurgical grade silicon in a mould having insulated bottom and side walls, and an open top; solidifying the melt by unidirectional solidification from the open top towards the bottom wall while electromagnetically stirring the melt; controlling a rate of the unidirectional solidification; stopping the unidirectional solidification when the melt has partially solidified to produce an ingot having an exterior shell including the higher-purity solid polycrystalline silicon and a center including an impurity-enriched liquid silicon; and creating an opening in the exterior shell of the ingot to outflow the impurity-enriched liquid silicon and leave the exterior shell which has the higher-purity solid polycrystalline silicon.

Process for the production of medium and high purity silicon from metallurgical grade silicon

The invention relates to an ascending pipe waste heat insertion-type temperature control thermal expansion decoking heat pipe guiding-out method and device, and belongs to the technical field of coking furnace ascending pipe raw gas waste heat recycling According to the technical scheme, a steam outlet pipe (13) and a water inlet pipe (14) are bent together to be of an L-type structure (1), the end of the horizontal segment of the L-type structure is provided with a detachable connector (22), the end of the perpendicular segment is provided with an anti-coking head (24), the steam outlet pipe is connected with a steam pocket (9), the water inlet pipe is connected with a water inlet system, raw gas and the water inlet pipe are isolated through the steam outlet pipe, the temperature of the exterior of the steam outlet pipe is not lower than the coking temperature, and meanwhile steam ascends gradually to heat inflowing water, so that the inflowing water is completely gasified According to the ascending pipe waste heat insertion-type temperature control thermal expansion decoking heat pipe guiding-out method and device, the temperature is detected through a high-temperature thermocouple in the heat exchange process, the water yield of the inflowing water is controlled, and therefore coking of the exterior of the device is avoided; raw gas waste heat can be recycled, completely independent installation is achieved, the problems that a heat exchange device inside an ascending pipe is prone to coking, the ascending pipe is prone to explosion, installation is difficult, and the replacement and maintenance cost is high are solved, and the heat exchange amount is large

Ascending pipe waste heat insertion-type temperature control thermal expansion decoking heat pipe guiding-out method and device

PROBLEM TO BE SOLVED: To provide a method for reforming high-temperature exhaust gas, a reforming apparatus and a method for producing the reformed gas from the exhaust gas generated from such a metallurgical furnace, by which heat-increasing of the exhaust gas and also, reduction of the exhaust of carbon dioxide gas can simultaneously be achieved by inducing efficient carbon dioxide gas reforming reaction without piling carbon, non-burning component in exhaust gas-system piping, etc. SOLUTION: The reforming method, the reforming apparatus and the method for producing the reformed gas are provided to perform the followings. When the reformation of the high-temperature exhaust gas exhausted from the metallurgical furnace, is performed by adding the reducing agent thereto, the addition start of the reducing agent is performed at the timing, in which by oxygen concentration in the exhaust gas becomes ≤1 vol%, and this reforming reaction is completed at the timing, in which the temperature of the exhaust gas is ≥800°C. COPYRIGHT: (C)2011,JPO&INPIT

Method for reforming exhaust gas generated from metallurgical furnace, reforming apparatus and method for producing reformed gas

PROBLEM TO BE SOLVED: To provide a method for producing a high calorie gas, by which CO 2 in a low calorie gas by-produced in a steel-making process can be reduced into CO at a low cost and in high reaction efficiency without an expensive carbon source and an outer energy. SOLUTION: This method for producing the high calorie gas, comprising reforming a low calorie gas containing CO 2 by-produced in a steel-making process using a catalyst, is characterized by supplying a coke oven gas having a hydrogen gas concentration of ≥60% and a temperature of ≥600°C to the low calorie gas to accelerate the reduction reaction of the CO 2 gas in the low calorie gas. COPYRIGHT: (C)2007,JPO&INPIT

Method for producing high calorie gas

A reforming method of a metallurgical furnace generated exhaust gas, comprising reforming a high temperature exhaust gas discharged from a metallurgical furnace by adding a reducing agent to the gas, wherein addition of the reducing agent is initiated when an oxygen concentration in the exhaust gas is 1 vol% or less, and a reforming reaction is completed when a temperature of the exhaust gas is 800°C or higher, and an apparatus thereof. The reducing agent is blown from a reducing agent blowing nozzle having a double pipe structure. A cooling method of a metallurgical furnace generated exhaust gas, comprising adding a reducing agent to the high temperature exhaust gas to induce an endothermic reaction between the reducing agent and the carbon dioxide gas in the exhaust gas, and cooling the exhaust gas itself by the endothermic reaction, and an apparatus thereof.

Process for reforming exhaust gas from metallurgical furnace, process for cooling the exhaust gas, and apparatuses for both processes

PROBLEM TO BE SOLVED: To recover a converter gas as a fuel gas having high gas calorie. SOLUTION: This method comprises mixing the converter gas with a coke- oven gas containing hydrogen abundantly, and reducing carbon dioxide in the converter gas into carbon monoxide with hydrogen, to greatly increase the gas calorie. Then, the gas can be recovered as the fuel gas, because a carbon monoxide content increases. The method comprises charging and mixing the coke-oven gas, particularly just after a start of and just before and end of operation of the converter, when having the high carbon-dioxide content and the low carbon-monoxide content. An oxygen content is made to be 0.5% or less for the purpose of preventing explosion. COPYRIGHT: (C)2003,JPO

Method for recovering converter gas

PROBLEM TO BE SOLVED: To provide a method for efficiently recovering sensible heat of coke oven gas. SOLUTION: This method comprises introducing CO2 containing gas such as exhaust gas of combustion to the lower end of the rising pipe 3 which leads the coke oven gas from the ammonia water spray 4 to the dry main 5, mixing said CO2 containing gas with the coke oven gas, endothermically reacting CO2 and H2 to make a high sensible heat state of CO and H2O, and recovering the sensible heat at that state as a chemical energy. Wherein, the temperature of the gas after mixing is 600 deg.C or more, preferably 750 deg.C or more, and the content of CO2 of the introduced gas is 10% or more.

Method for recovering sensible heat of coke oven gas

PROBLEM TO BE SOLVED: To provide an apparatus for unidirectional congelation of silicon allowing to keep productivity of ingot at a high level and to make the concentration of impurity element throughout the ingot more uniform than in prior arts. SOLUTION: In an apparatus for unidirectional congelation of silicon equipped with a casting mold to congeal molten silicon, a heating means to heat silicon, a cooling chamber located underneath of the casting mold, a cooling means to cool the silicon in the casting mold from below, sensors to detect the congealing interface provided at the side wall of the casting mold in multiple steps, and a control means of congealing rate calculating the rate of congelation from the measured values at each sensor, comparing it with the target rate of congelation, and supplying the output to the heating means and cooling means, the cooling means provided in the cooling chamber is constituted from a chiller plate and cooling gas flowing around it, and the electric heater is located below the casting mold and above the chiller plate.

Apparatus for unidirectional congelation of silicon

PROBLEM TO BE SOLVED: To solve the problem that the temperature of the atmospheric gas in a regenerative gas heater for continuously supplying the heated atmospheric gas is time sequentially changed, by providing >=3 regenerative heaters and successively switching the heaters to the burning state and the heating state and suction state of the atmospheric gas SOLUTION: A cooling gas is mixed in the atmospheric gas discharged from the first regenerator of the regenerative heater in the atmospheric gas heating state

Method for regulating heating temperature of atmospheric gas and heating temperature regulator

PROBLEM TO BE SOLVED: To improve the heating efficiency of a ladle, in which the atmosphere temperature in the ladle can be heated to high temperature so that the combustion exhaust gas temperature at outlet side of a heat-storage body does not exceed the heat-resistant temperature of a member for supporting the heat-storage body and a switch valve for changing over interposed in the exhaust gas piping. SOLUTION: The upper opening part of the ladle 1 is closed with a ladle cover 12 fitting one pair of burner parts 112a, 112b alternately executing the supply of the air for combustion and the exhaust of the combustion exhaust gas through the heat- storage bodies 113a, 113b. In this state, one pair of the burner parts 112a, 112b are alternately burnt in the ladle 1 and also, the combustion exhaust gas is exhausted and recovered through the exhaust gas piping 123 by passing through the heat-storage body 113b at the burner 112b side during stopping the combustion. In this way, in the method for rapidly heating the ladle 1, the combustion exhaust gas temperature at the outlet side of the heat-storage body 113b is measured with a thermometer Tb and a flow-rate adjusting valve 125 interposed in the exhaust gas piping 123 is controlled based on this measured temperature to control the recovering amount of the combustion exhaust gas.

Adachi Kazunari

Papers

Method for recovering converter gas

Method for recovering sensible heat of coke oven gas

Apparatus for unidirectional congelation of silicon

Method for regulating heating temperature of atmospheric gas and heating temperature regulator

Rapidly heating method of ladle using heat-storage type burner