The invention relates to a method and to a device for stabilizing precursor fibers for the production of carbon fibers. In the method, precursor fibers are first heated to a first temperature and held at the temperature for a predefined duration. Subsequently, the precursor fibers are heated to at least one second temperature, which is higher than the first temperature, and held at said temperature for a predefined duration. During each heating and between the heating steps, the precursor fibers are in a gas atmosphere having a negative pressure in the range between 12 mbar and 300 mbar and having an oxygen partial pressure of 2.5 to 63 mbar. The device has at least one evacuable, elongate vacuum chamber for feeding the precursor fibers through, at least two lock units and at least one heating unit. At least one lock unit is used for the sealed insertion of precursor fibers into the at least one vacuum chamber, while at least one other lock unit is used for the sealed removal of precursor fibers from the at least one vacuum chamber. The heating unit has at least two individually controllable heating elements, which are suitable for heating the at least one vacuum chamber to at least two different temperatures in heating zones which are adjacent in the longitudinal direction.

A method for volume heat treating a part having an external surface delimiting its volume, the method comprising the following steps: a. providing a laser source; b. providing the part; c. providing support means for supporting the part; d. placing said part so that it is held in position by said support means; and e. irradiating with the laser source at least one segment of the external surface of the part with a laser exposure power and duration to obtain a temperature rise in essentially the entire volume of the part.

A method for volume heat treating a part having an external surface delimiting its volume, the method comprising the following steps: a. providing a laser source; b. providing the part; c. providing support means for supporting the part; d. placing said part so that it is held in position by said support means; and e. irradiating with the laser source at least one segment of the external surface of the part with a laser exposure power and duration to obtain a temperature rise in essentially the entire volume of the part.

A decarburization end point determination method includes: estimating the carbon concentration and oxygen concentration of the molten steel and carbon dioxide gas concentration of exhaust gas in the vacuum chamber by using measurement values of the carbon concentration and the oxygen concentration of the molten steel, a measurement value of internal pressure of the vacuum chamber, and a model formula; correcting a parameter included in the model formula to reduce at least one of a difference between an estimate value and a measurement value of the oxygen concentration and a difference between an estimate value and a measurement value of the carbon dioxide gas concentration of the exhaust gas; estimating the carbon concentration of the molten steel by using the model formula in which the parameter is corrected; and determining timing when an estimate value reaches a target value as the completion time point of the vacuum decarburization treatment.

A decarburization end point determination method includes: estimating the carbon concentration and oxygen concentration of the molten steel and carbon dioxide gas concentration of exhaust gas in the vacuum chamber by using measurement values of the carbon concentration and the oxygen concentration of the molten steel, a measurement value of internal pressure of the vacuum chamber, and a model formula; correcting a parameter included in the model formula to reduce at least one of a difference between an estimate value and a measurement value of the oxygen concentration and a difference between an estimate value and a measurement value of the carbon dioxide gas concentration of the exhaust gas; estimating the carbon concentration of the molten steel by using the model formula in which the parameter is corrected; and determining timing when an estimate value reaches a target value as the completion time point of the vacuum decarburization treatment.

A process of calcining aluminium hydroxide (Al.sub.2O.sub.3.3H.sub.2O) to form alumina (Al.sub.2O.sub.3), for example in an alumina plant, such as a Bayer process plant, is disclosed. The process comprises combusting hydrogen and oxygen and generating steam and heat 5 and using the heat to calcine aluminium hydroxide and form alumina and more steam. An apparatus is also disclosed.

Disclosed is a pumping system with reduced contamination. A vacuum pump system includes a mechanical vacuum pump mechanism within a hermetic pump that hermetically isolates the pump mechanism from ambient air. A pump inlet is hermetically sealed to the hermetic pump housing. A pump outlet is hermetically sealed at one end to the hermetic pump housing and at the other end to an inlet of a Peclet seal tube. The vacuum pump system produces a vacuum in a vacuum processing chamber. A sweep gas source injects a sweep gas into at least one of (i) the hermetic pump housing and (ii) the inlet of the Peclet seal tube. The sweep gas and a process gas flow through the Peclet seal tube to substantially isolate against the backflow of the ambient air through the Peclet seal tube.

A system for treating tin smelting intermediate materials and method for treating the materials is disclosed. The system includes a fuming furnace, an electric settling furnace, a lean slag water quenching pool, a matte ladle, a pulverized coal injection system, a flue gas treatment system and a secondary air supply system; the fuming furnace is connected with the electric settling furnace, the pulverized coal injection system, the flue gas treatment system and the secondary air supply system respectively; the electric settling furnace is also connected with the slag-lean water quenching pool and the matte ladle respectively. The system and method disclosed by the disclosure can efficiently classify, separate and recover tin from other materials, solve the problems of difficult sales and transportation of complex tin-containing smelting intermediate materials and economic loss of discounted sales, and transform hazardous wastes into value-added valuable materials for comprehensive recovery.

A system for treating tin smelting intermediate materials and method for treating the materials is disclosed. The system includes a fuming furnace, an electric settling furnace, a lean slag water quenching pool, a matte ladle, a pulverized coal injection system, a flue gas treatment system and a secondary air supply system; the fuming furnace is connected with the electric settling furnace, the pulverized coal injection system, the flue gas treatment system and the secondary air supply system respectively; the electric settling furnace is also connected with the slag-lean water quenching pool and the matte ladle respectively. The system and method disclosed by the disclosure can efficiently classify, separate and recover tin from other materials, solve the problems of difficult sales and transportation of complex tin-containing smelting intermediate materials and economic loss of discounted sales, and transform hazardous wastes into value-added valuable materials for comprehensive recovery.

A furnace system including an outer shell which comprises a top flange, an elongated body portion, and a bottom flange, wherein the outer shell is a pressure vessel, with no penetrations in the elongated body portion; a heater assembly which comprises (i) a single-piece annular shaped insulation layer, and (ii) a plurality of heaters embedded in the insulation layer, wherein the heater assembly is disposed within the elongated body portion of the outer shell; and an innermost layer disposed within the annular-shaped insulation layer, wherein the innermost layer is a baffle tube configured to force a natural convective flow, wherein each of the plurality of heaters is individually controllable and the plurality of heaters are configured to heat different zones within the furnace to different temperatures and/or at different rates. The system may be used to heat treat magnet materials, such as those formed of Bi-2212, therein.