Provided is steel for a wind power gear with improved purity and reliability. The chemical components thereof comprise, in percentages by mass: 0.15-0.19% of C, ≤0.4% of Si, 0.5-0.7% of Mn, ≤0.012% of P, ≤0.006% of S, 1.5-1.8% of Cr, 0.28-0.35% of Mo, 1.4-1.7% of Ni, and 0.02-0.04% of Al, with the balance being Fe and inevitable impurities. A smelting method therefor comprises adding raw materials to a converter for primary melting, transferring same to a refining furnace for refining, carrying out continuous casting after vacuum degassing, and transferring same to a gas protection furnace for electroslag remelting. According to the present invention, a pure electroslag master batch is obtained by continuous casting, and the purity of the material is further improved by means of an electroslag remelting procedure; and the prepared steel material is used in a wind power gear, such that the flaw detection pass rate is significantly increased, large-particle inclusions in the steel material are significantly reduced, and the inclusions are fine and dispersed.

An efficient long-service-life blowing method include the steps of introducing vanadium extraction converter flue gas and decarburization converter flue gas into an oxygen combustor; obtaining first-purity CO.sub.2—N.sub.2 mixed gas through the vanadium extraction converter flue gas; obtaining second-purity CO.sub.2—N.sub.2 mixed gas through the decarburization converter flue gas; obtaining O.sub.2—CO.sub.2—N.sub.2 mixed gas through the decarburization converter flue gas; obtaining first-purity CO.sub.2 gas through the second-purity CO.sub.2—N.sub.2 mixed gas; and using the first-purity CO.sub.2—N.sub.2 mixed gas for bottom blowing of the vanadium extraction converter, using the second-purity CO.sub.2—N.sub.2 mixed gas as a carrier gas for blowing iron ore powder into the vanadium extraction converter, and using the O.sub.2—CO.sub.2—N.sub.2 mixed gas and the first-purity CO.sub.2 gas as a carrier gas for bottom blowing of the decarburization converter and bottom injecting of lime powder into the decarburization converter.

An efficient long-service-life blowing method include the steps of introducing vanadium extraction converter flue gas and decarburization converter flue gas into an oxygen combustor; obtaining first-purity CO.sub.2—N.sub.2 mixed gas through the vanadium extraction converter flue gas; obtaining second-purity CO.sub.2—N.sub.2 mixed gas through the decarburization converter flue gas; obtaining O.sub.2—CO.sub.2—N.sub.2 mixed gas through the decarburization converter flue gas; obtaining first-purity CO.sub.2 gas through the second-purity CO.sub.2—N.sub.2 mixed gas; and using the first-purity CO.sub.2—N.sub.2 mixed gas for bottom blowing of the vanadium extraction converter, using the second-purity CO.sub.2—N.sub.2 mixed gas as a carrier gas for blowing iron ore powder into the vanadium extraction converter, and using the O.sub.2—CO.sub.2—N.sub.2 mixed gas and the first-purity CO.sub.2 gas as a carrier gas for bottom blowing of the decarburization converter and bottom injecting of lime powder into the decarburization converter.

A method to control slag foaming in a smelting process in a vessel for smelting an iron-containing feed material including the steps of: measuring vibration of the metallurgical vessel with an accelerometer at one or more positions on the vessel, comparing values derived from accelerometer data with a threshold value which indicates the onset of a slag foaming incident, and adjusting the smelting process if the value derived from the accelerometer data passes a predefined alarm value, wherein the smelting process is adjusted by adjusting the amounts of the gaseous and/or the solid components injected in the smelting process.

A method to control slag foaming in a smelting process in a vessel for smelting an iron-containing feed material including the steps of: measuring vibration of the metallurgical vessel with an accelerometer at one or more positions on the vessel, comparing values derived from accelerometer data with a threshold value which indicates the onset of a slag foaming incident, and adjusting the smelting process if the value derived from the accelerometer data passes a predefined alarm value, wherein the smelting process is adjusted by adjusting the amounts of the gaseous and/or the solid components injected in the smelting process.

An efficient long-service-life blowing method include the steps of introducing vanadium extraction converter flue gas and decarburization converter flue gas into an oxygen combustor; obtaining first-purity CO.sub.2N.sub.2 mixed gas through the vanadium extraction converter flue gas; obtaining second-purity CO.sub.2N.sub.2 mixed gas through the decarburization converter flue gas; obtaining O.sub.2CO.sub.2N.sub.2 mixed gas through the decarburization converter flue gas; obtaining first-purity CO.sub.2 gas through the second-purity CO.sub.2N.sub.2 mixed gas; and using the first-purity CO.sub.2N.sub.2 mixed gas for bottom blowing of the vanadium extraction converter, using the second-purity CO.sub.2N.sub.2 mixed gas as a carrier gas for blowing iron ore powder into the vanadium extraction converter, and using the O.sub.2CO.sub.2N.sub.2 mixed gas and the first-purity CO.sub.2 gas as a carrier gas for bottom blowing of the decarburization converter and bottom injecting of lime powder into the decarburization converter.

An efficient long-service-life blowing method include the steps of introducing vanadium extraction converter flue gas and decarburization converter flue gas into an oxygen combustor; obtaining first-purity CO.sub.2N.sub.2 mixed gas through the vanadium extraction converter flue gas; obtaining second-purity CO.sub.2N.sub.2 mixed gas through the decarburization converter flue gas; obtaining O.sub.2CO.sub.2N.sub.2 mixed gas through the decarburization converter flue gas; obtaining first-purity CO.sub.2 gas through the second-purity CO.sub.2N.sub.2 mixed gas; and using the first-purity CO.sub.2N.sub.2 mixed gas for bottom blowing of the vanadium extraction converter, using the second-purity CO.sub.2N.sub.2 mixed gas as a carrier gas for blowing iron ore powder into the vanadium extraction converter, and using the O.sub.2CO.sub.2N.sub.2 mixed gas and the first-purity CO.sub.2 gas as a carrier gas for bottom blowing of the decarburization converter and bottom injecting of lime powder into the decarburization converter.

Jacketed rotary converter. The converter includes an inclined pot mounted for rotation about a longitudinal axis, a refractory lining for holding a molten alloy pool, an opening in a top of the pot for introducing feed, a lance for injecting oxygen-containing gas, a heat transfer jacket for the pot 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. Also disclosed is a PGM converting process using the jacketed rotary converter. The process can also include low-or no-flux converting; refractory protectant addition; slag separation; partial feed pre-oxidation; staged slagging; and/or smelting the slag in a secondary furnace with primary furnace slag.

Jacketed rotary converter. The converter includes an inclined pot mounted for rotation about a longitudinal axis, a refractory lining for holding a molten alloy pool, an opening in a top of the pot for introducing feed, a lance for injecting oxygen-containing gas, a heat transfer jacket for the pot 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. Also disclosed is a PGM converting process using the jacketed rotary converter. The process can also include low-or no-flux converting; refractory protectant addition; slag separation; partial feed pre-oxidation; staged slagging; and/or smelting the slag in a secondary furnace with primary furnace slag.

A process and system having a primary crusher to reduce the fragments according to their granulometry; a magnetic separator to remove metallic fragments bigger than a determined granulometry; a rotary dryer to dry slag; an impact mill to disaggregate and fragment slag particles; a classifier for aero-classification and drag of fine and superfine particles; a cooler for cooling slag by means of heat exchange and removal of the fine and superfine particles that were not collected by the impact mill a vibrating sieve provided with two or more decks with screens of predetermined sizes; low-intensity magnetic separators, with generation of non-magnetic slag fractions free from metallic iron and from iron monoxide, and of magnetic fractions composed by metallic iron and iron monoxide; and low-intensity magnetic separators to reprocess the magnetic fractions with generation of concentrate with high metallic iron contents and a product with high concentration of iron monoxide.