When performing dephosphorization treatment of hot metal by adding a refining agent as a lime source and an oxygen source (dephosphorizing agent(s) and a gaseous oxygen source into the hot metal accommodated in a hot metal holding container, the refining agent used is a refining agent having an Ig-loss value of from 4.0% by mass to 35.0% by mass and including 60% by mass or more of quicklime.

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.

The present disclosure is related to compacted calcium-based granules, in particular pellets, spheroidal/lens-shaped pellets, exhibiting specific chemical and physical properties and comprising a source of calcium and/or a source of magnesium, and optionally one or more additives. The present disclosure further relates to a method for the production of said pellets and to the use of said pellets in, for example, the steel industry, agriculture (in particular precision farming) and the glass industry.

A method of making steel by deeply dephosphorization in a hot metal tank and decarburization using semi-steel with nearly zero phosphorus load in a converter includes the following steps: putting an efficient dephosphorization agent into the hot metal tank in advance, and conducting dephosphorization during blast furnace tapping and transportation of blast furnace hot metal by the hot metal tank to obtain semi-steel with [P] less than 0.04 wt. % and [C] greater than or equal to 3.5 wt. %; and removing dephosphorization slag, and pouring the semi-steel into the converter for decarburization to obtain molten steel. The efficient dephosphorization agent includes iron oxide scale, lime, and composite calcium ferrite. According to the method, a phosphorus content of the blast furnace hot metal is reduced to be less than or equal to 0.04 wt. % through the efficient dephosphorization agent.

Proposed is a method for removing phosphorus from a phosphorus-containing substance which is applicable in an industrial scale so as to effectively reduce phosphorus contained in the phosphorus-containing substance. In this method, the phosphorus-containing substance used as a raw material for metal smelting or metal refining is reacted with a nitrogen-containing gas at a treatment temperature T (° C.) which is lower than a melting temperature (T.sub.m) of the substance, so that phosphorus is removed preferably in the form of phosphorus nitride (PN). In this regard, a nitrogen partial pressure and an oxygen partial pressure in the nitrogen-containing gas are preferably controlled, thereby reducing a load of dephosphorization process, for example.

Process for dephosphorization of molten metal during a refining process using a lime composition in the form of compacted particles having a Shatter Test Index of less than 20%, leading to a refined metal reduced in phosphorus components to the extent that the refined metal reduced in phosphorus is showing a phosphorus content lower than 0.02 w % based on the total weight of the refined metal reduced in phosphorus.

A method of making steel by deeply dephosphorization in a hot metal tank and decarburization using semi-steel with nearly zero phosphorus load in a converter includes the following steps: putting an efficient dephosphorization agent into the hot metal tank in advance, and conducting dephosphorization during blast furnace tapping and transportation of blast furnace hot metal by the hot metal tank to obtain semi-steel with [P] less than 0.04 wt. % and [C] greater than or equal to 3.5 wt. %; and removing dephosphorization slag, and pouring the semi-steel into the converter for decarburization to obtain molten steel. The efficient dephosphorization agent includes iron oxide scale, lime, and composite calcium ferrite. According to the method, a phosphorus content of the blast furnace hot metal is reduced to be less than or equal to 0.04 wt. % through the efficient dephosphorization agent.

The method employs a desulfurization agent that is introduced into a smelt of one of molten pig iron and molten steel. The desulfurization agent contains calcium oxide, bitumen and at least one flux agent, with the agent containing 1 to 10% by weight bitumen.

Process for manufacturing a slag conditioning agent for steel desulfurization wherein a dried slag material obtained from secondary steelmaking process is mixed with quicklime particles to produce a slag conditioning agent.

A device and a method for continuous desulphurisation of liquid iron provided by a blast furnace process or a direct reduction process.