A method of fabricating a low alloy steel ingot, the method including a) melting all or part of an electrode by a vacuum arc remelting method, the electrode, before melting, including iron and carbon, the melted portion of the electrode being collected in a crucible, thus forming a melt pool within the crucible; and b) solidifying the melt pool by heat exchange between the melt pool and a cooling fluid, the heat exchange applied serving to impose a mean solidification speed during step b) that is less than or equal to 45 m/s and to obtain an ingot of low alloy steel.

A method produces tantalum powder by reducing tantalum oxide with an alkaline earth metal. The method includes (1) mixing tantalum oxide with an excessive alkaline earth metal reducing agent, simultaneously mixing at least one alkali metal and/or alkaline earth metal halide accounting for 10-200% of the weight of the tantalum oxide, heating the mixture to a temperature of 700-1200? C. in a furnace filled with inert gas, and soaking so that the tantalum oxide and reducing agent are subjected to a reduction reaction; (2) at the end of soaking, lowering the temperature to 600-800? C., vacuumizing the interior of the furnace to 10 Pa or less, and soaking under the negative pressure so that the excessive magnesium and tantalum powder mixture are separated; (3) thereafter, raising the temperature of the furnace to 750-1200? C. in the presence of inert gas, and soaking so that the tantalum powder is further sintered in the molten salt; (4) then cooling to room temperature and passivating to obtain a mixed material containing halide and tantalum powder; and (5) separating the tantalum powder from the mixture.

Disclosed is a thermal reduction apparatus. The thermal reduction apparatus according to the exemplary embodiment includes: a preheating unit which preheats a to-be-reduced material and loads the to-be-reduced material into a reducing unit; the reducing unit which is connected to the preheating unit and in which a thermal reduction reaction of the to-be-reduced material occurs; a cooling unit which is connected to the reducing unit and from which the to-be-reduced material flowing into the cooling unit is unloaded to the outside; a gate device which is installed between the preheating unit and the reducing unit; a gate device which is installed between the reducing unit and the cooling unit; a condensing device which is connected to the reducing unit and condenses a metal vapor; a first blocking unit which is installed in the reducing unit; and a second blocking unit which is installed in the reducing unit so as to be spaced apart from the first blocking unit.

The present invention discloses a method for producing high-purity magnesium by semi-continuous distillation, comprising the following steps of: (1) melting crude magnesium or recycled mixed metal containing magnesium containing various impurities in a melting boiler; (2) feeding the molten crude magnesium into a second boiler by a magnesium liquid delivery pump, and maintaining a temperature of 665 C. to 700 C.; (3) sucking the high-temperature magnesium liquid into a crude distillation column in vacuum by a magnetic liquid suction pipe that is inserted into the intermediate boiler and connected to the crude distillation column. Magnesium is condensed into liquid in the rectification column, then discharged from a liquid seal of the rectification column, and ingoted in a refined magnesium die to obtain high-purity magnesium products.

The invention provides a method for the recovery of a metal-containing product (M.sub.Prod) comprising: providing a composite material comprising a matrix of oxidised reductant (R.sub.o), a product metal (M.sub.P) dispersed in the matrix of oxidised reductant (R.sub.o), and one or more metal compounds (M.sub.PC.sub.R) of the product metal (M.sub.P) in one or more oxidation states dispersed in the matrix of oxidised reductant (R.sub.o); and treating the composite material to at least partially remove the one or more metal compounds (M.sub.PC.sub.R) from the matrix of oxidised reductant (Ro) to form the metal-containing product (M.sub.Prod).

The invention provides a method for the recovery of a metal-containing product (M.sub.Prod) comprising: providing a composite material comprising a matrix of oxidised reductant (R.sub.o), a product metal (M.sub.P) dispersed in the matrix of oxidised reductant (R.sub.o), and one or more metal compounds (M.sub.PC.sub.R) of the product metal (M.sub.P) in one or more oxidation states dispersed in the matrix of oxidised reductant (R.sub.o); and treating the composite material to at least partially remove the one or more metal compounds (M.sub.PC.sub.R) from the matrix of oxidised reductant (Ro) to form the metal-containing product (M.sub.Prod).

A low thermal expansion superalloy is composed of, in mass %, 0.1% or less of C, 0.1-1.0% of Si, 1.0% or less of Mn, 25-32% of Ni, more than 18% but less than 24% of Co, more than 0.25% but 1.0% or less of Al, 0.5-1.5% of Ti, more than 2.1% but less than 3.0% of Nb, 0.001-0.01% of B and 0.0005-0.01% of Mg, with the balance of Fe and unavoidable impurities, while satisfying Mg/S1, 52.91.235Ni+Co<55.8%, (Al+Ti+Nb) is 3.5-5.5%, and the F value is 8% or less. In the superalloy, a granular intermetallic compound containing Si, Nb, and Ni alone or in a total amount of 36 mass % or more is precipitated at a grain boundary of an austenite matrix, and an intermetallic compound including a larger concentration of Ni, Al, Ti, and Nb and having 50 nm or smaller of an average diameter is precipitated in the austenite matrix.

A low thermal expansion superalloy is composed of, in mass %, 0.1% or less of C, 0.1-1.0% of Si, 1.0% or less of Mn, 25-32% of Ni, more than 18% but less than 24% of Co, more than 0.25% but 1.0% or less of Al, 0.5-1.5% of Ti, more than 2.1% but less than 3.0% of Nb, 0.001-0.01% of B and 0.0005-0.01% of Mg, with the balance of Fe and unavoidable impurities, while satisfying Mg/S1, 52.91.235Ni+Co<55.8%, (Al+Ti+Nb) is 3.5-5.5%, and the F value is 8% or less. In the superalloy, a granular intermetallic compound containing Si, Nb, and Ni alone or in a total amount of 36 mass % or more is precipitated at a grain boundary of an austenite matrix, and an intermetallic compound including a larger concentration of Ni, Al, Ti, and Nb and having 50 nm or smaller of an average diameter is precipitated in the austenite matrix.

The present invention discloses a production system for a hafnium crystal bar and the method thereof. The technical program includes a power supply unit with large DC current, an iodizer, a molybdenum insulator provided inside the iodizer, a thermostatic device, a cooling unit, a vacuum unit, an iodine box for iodizing the iodizer, an electrode unit electrically connected to the power supply unit, wherein the electrode unit is disposed above the iodizer, a crystallization unit provided inside the iodizer, wherein the crystallization unit is connected to the electrode unit, and a rough hafnium provided between the iodizer and the molybdenum insulator. The thermostatic device is a structure with an insulation layer provided outside an inner tank, and an electric heating wire is provided between the inner tank and the insulation layer. The inner tank of the thermostatic device is filled with a saline solution.

A method for producing metal alloys. The method allows the production of metal alloys consisting of at least two metals having a high melting point difference. Here, the higher melting metal is melted first and the lower melting metal is melted with a delay by means of heat transfer whereupon the metals mix together. This enables to obtain metal alloys with high purity and low evaporation losses, which in particular allow the use of contaminated starting components such as recycled metal.