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.

A fluorite synthetic stone comprises: (a) a glass matrix comprising Ca, Si and O, and having a predetermined weight ratio of Ca to Si; and (b) CaF.sub.2 crystals dispersed in the glass matrix at a concentration of at least about 70 wt.%. A method of making fluorite synthetic stones includes formulating a particulate mixture comprising: CaF.sub.2 crystals at a concentration of at least about 70 wt.%; and an excipient having a predetermined weight ratio of Ca to Si. Aggregates are prepared from the particulate mixture. The aggregates are heat treated to form a plurality of fluorite synthetic stones, where each synthetic stone comprises: a glass matrix comprising Ca, Si and O; and CaF.sub.2 crystals dispersed in the glass matrix at a concentration of at least about 70 wt.%.

Provided are a Kanbara Reactor (KR) desulfurization stirring paddle casting material and a preparation method therefor. The casting material consists of a base material and an additive; the base material consists of the following raw materials in weight percentages: M70 sintered mullite 60-80%, flint clay 5-20%, fine powder 5-20%, and pure calcium aluminate cement 1-5%. The percentages of each component of the additive based on the weight of the base material are as follows: water reducing agent 0.05-0.2%, and heat-resistant stainless steel fiber 1-5%. The main raw materials are M70 sintered mullite and a small amount of flint clay so as to ensure good thermal shock resistance; the medium temperature and high temperature strength are controlled at 100-180 MPa so as to ensure good erosion resistance; the content of Al.sub.2O.sub.3 in the casting material is 60-70% so as to ensure good corrosion resistance; the ratio of high temperature strength to medium temperature strength is controlled at 1-1.2, which further improves the thermal shock resistance and peeling resistance of the casting material, thereby extending the service life of the stirring paddle. The casting material is lower in cost and has a good practical furnace usage effect; in addition, a paddle blade has less chance of cracking and peeling, while a bottom portion of the stirring paddle is less eroded, thus the frequency of paddle blade repair is low, and service life is significantly improved.

A manufacturing method includes a first pulverization step of compressively pulverizing a manganese oxide-containing material containing at least manganese, calcium, silicon, iron, and phosphorus, which is used as a raw material, to form a composite in which a compound phase of nCaO.P.sub.2O.sub.5 is combined with at least one phase of a spinel phase and a calcium ferrite phase, which are ferromagnetic materials, and produce a first pulverized manganese oxide-containing material containing the composite; a first magnetic separation step of separating the first pulverized manganese oxide-containing material produced in the pulverization step into a magnetic substance and a non-magnetic substance under a magnetic force; and a step of recovering the non-magnetic substance separated in the first magnetic separation step as a manganese raw material.

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.

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.

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.

Provided are a Kanbara Reactor (KR) desulfurization stirring paddle casting material and a preparation method therefor. The casting material consists of a base material and an additive; the base material consists of the following raw materials in weight percentages: M70 sintered mullite 60-80%, flint clay 5-20%, fine powder 5-20%, and pure calcium aluminate cement 1-5%. The percentages of each component of the additive based on the weight of the base material are as follows: water reducing agent 0.05-0.2%, and heat-resistant stainless steel fiber 1-5%. The main raw materials are M70 sintered mullite and a small amount of flint clay so as to ensure good thermal shock resistance; the medium temperature and high temperature strength are controlled at 100-180 MPa so as to ensure good erosion resistance; the content of Al.sub.2O.sub.3 in the casting material is 60-70% so as to ensure good corrosion resistance; the ratio of high temperature strength to medium temperature strength is controlled at 1-1.2, which further improves the thermal shock resistance and peeling resistance of the casting material, thereby extending the service life of the stirring paddle. The casting material is lower in cost and has a good practical furnace usage effect; in addition, a paddle blade has less chance of cracking and peeling, while a bottom portion of the stirring paddle is less eroded, thus the frequency of paddle blade repair is low, and service life is significantly improved.

A process for manufacturing a slag conditioning agent for steel desulfurization is shown in which a dried slag material Obtained from a secondary steelmaking process is mixed with quicklime particles. The quicklime particles react with moisture in the slag material to dry the slag material and produce a blend of slag material, hydrated lime and any unreacted quicklime. The blend is then sieved to separate out the hydrated lime. The retained dried fraction after sieving is then mixed with an Al.sub.2O.sub.3 mass fraction from which the slag conditioning agent can be collected. The slag conditioning agent has an equivalent mass ratio which is between 0.55 and 1.5.

A slag conditioning agent for steel desulfurization is shown which is made by a process in which a dried slag material obtained from a secondary steelmaking process is mixed with quicklime particles. The quicklime particles react with moisture in the slag material to dry the slag material and produce a blend of slag material, hydrated lime and any unreacted quicklime. The blend is then sieved to separate out the hydrated lime. The retained dried fraction after sieving is then mixed with an Al.sub.2O.sub.3 mass fraction from which the slag conditioning agent can be collected. The slag conditioning agent has an equivalent mass ratio which is between 0.55 and 1.5.