A metal melting apparatus capable of providing a clear melt with little oxides, even when either one or a mixture of scrap material and fresh material is supplied. Solution is provided by a metal melting apparatus including melting chamber to which a melt raw material is supplied, and gas injection system for injecting gas into melt in the melting chamber to generate a vortex of melt in the melting chamber.

A method and system of controlling a melting process of copper in a copper melting furnace including measuring at least one furnace parameter, wherein the at least one furnace parameter includes one or both of a furnace temperature and a furnace exhaust oxygen concentration, calculating a first rate of change of the furnace parameter over a first time period, calculating a second rate of change of the furnace parameter over a second time period at least a portion of which occurs after the first time period, comparing the first rate of change with the second rate of change, and indicating substantial completion of a process phase in the furnace when the second rate of change deviates by a predetermined threshold percentage from the first rate of change.

A method and system of controlling a melting process of copper in a copper melting furnace including measuring at least one furnace parameter, wherein the at least one furnace parameter includes one or both of a furnace temperature and a furnace exhaust oxygen concentration, calculating a first rate of change of the furnace parameter over a first time period, calculating a second rate of change of the furnace parameter over a second time period at least a portion of which occurs after the first time period, comparing the first rate of change with the second rate of change, and indicating substantial completion of a process phase in the furnace when the second rate of change deviates by a predetermined threshold percentage from the first rate of change.

A production method of a maraging steel includes: the step of producing, by vacuum melting, a remelt electrode which comprises from 0.2 to 3.0% by mass of Ti and from 0.0025 to 0.0050% by mass of N; and the step of remelting the remelt electrode to produce a steel ingot having an average diameter of 650 mm or more; wherein the resulting maraging steel includes from 0.2 to 3.0% by mass of Ti.

PGM converting process and jacketed rotary converter. The process can include low- or no-flux converting; partial pre-oxidation of PGM collector alloy; using a refractory protectant in the converter; magnetic separation of slag; recycling part of the slag to the converter; smelting catalyst material in a primary furnace to produce the collector alloy; and/or smelting the converter slag in a secondary furnace with slag from the primary furnace. The converter can include an inclined converter pot mounted for rotation; a refractory lining; an opening in a top of the pot to introduce converter feed; a lance for injecting oxygen-containing gas into the alloy pool; a heat transfer jacket adjacent the refractory lining; and a coolant system to circulate a heat transfer medium through the jacket to remove heat from the alloy pool in thermal communication with the refractory lining.

PGM converting process and jacketed rotary converter. The process can include low- or no-flux converting; partial pre-oxidation of PGM collector alloy; using a refractory protectant in the converter; magnetic separation of slag; recycling part of the slag to the converter; smelting catalyst material in a primary furnace to produce the collector alloy; and/or smelting the converter slag in a secondary furnace with slag from the primary furnace. The converter can include an inclined converter pot mounted for rotation; a refractory lining; an opening in a top of the pot to introduce converter feed; a lance for injecting oxygen-containing gas into the alloy pool; a heat transfer jacket adjacent the refractory lining; and a coolant system to circulate a heat transfer medium through the jacket to remove heat from the alloy pool in thermal communication with the refractory lining.

A metal melting apparatus capable of providing a clear melt with little oxides, even when either one or a mixture of scrap material and fresh material is supplied. Solution is provided by a metal melting apparatus including melting chamber to which a melt raw material is supplied, and gas injection system for injecting gas into melt in the melting chamber to generate a vortex of melt in the melting chamber.

A metal melting apparatus capable of providing a clear melt with little oxides, even when either one or a mixture of scrap material and fresh material is supplied. Solution is provided by a metal melting apparatus including melting chamber to which a melt raw material is supplied, and gas injection system for injecting gas into melt in the melting chamber to generate a vortex of melt in the melting chamber.

The invention discloses a method for removing the slag during the remelting of Ni-based superalloy, including: the master Ni-based superalloy is placed in a crucible located in a vacuum induction melting furnace; under the condition of maintaining a predetermined vacuum degree, the furnace cavity is heated to melt the master Ni-based superalloy, during the melting process, the metallic element Ca is thrown into the alloy melt, when the temperature in the furnace cavity rises to a predetermined degree, the master Ni-based superalloy is completely melted, at this time, the slag is formed on the surface of the alloy melt. When the master Ni-based superalloy is completely melted and enters the smelting stage, the metallic elements Ca, Ba, and Sr are put into the alloy melt in turn and the electromagnetic stirring is performed to rapidly remove the slag on the surface of the alloy melt.

The invention discloses a method for removing the slag during the remelting of Ni-based superalloy, including: the master Ni-based superalloy is placed in a crucible located in a vacuum induction melting furnace; under the condition of maintaining a predetermined vacuum degree, the furnace cavity is heated to melt the master Ni-based superalloy, during the melting process, the metallic element Ca is thrown into the alloy melt, when the temperature in the furnace cavity rises to a predetermined degree, the master Ni-based superalloy is completely melted, at this time, the slag is formed on the surface of the alloy melt. When the master Ni-based superalloy is completely melted and enters the smelting stage, the metallic elements Ca, Ba, and Sr are put into the alloy melt in turn and the electromagnetic stirring is performed to rapidly remove the slag on the surface of the alloy melt.