The present invention provides a method for preparing ferrovanadium alloys based on aluminothermic self-propagating gradient reduction and slag washing refining. The method includes the steps of (1) performing aluminothermic self-propagating gradient reduction; (2) performing heat preserving and smelting to obtain an upper layer alumina-based slag and a lower layer alloy melt; (3) jetting refining slags into the lower layer alloy melt, and performing stirring and slag washing refining; and (4) cooling the refined high-temperature melt to room temperature, and removing an upper layer smelting slag to obtain the ferrovanadium alloys.

A system and method for recovering a high yield of low carbon ferrochrome from chromite and low carbon ferrochrome produced therefrom. A stoichiometric mixture of feed materials including scrap aluminum granules, lime, silica sand, and chromite ore are provided into a plasma arc furnace. The scrap aluminum granules are produced from used aluminum beverage containers. The feed materials are heated, whereupon the aluminum in the aluminum granules produces an exothermic reaction reducing the chromium oxide and iron oxide in the chromite to produce molten low carbon ferrochrome with molten slag floating thereon. The molten low carbon ferrochrome is extracted, solidified and granulated into granules of low carbon ferrochrome. The molten slag is extracted, solidified and granulated into granules of slag.

A method and system for recovering a high yield of low carbon ferrochrome from chromite and low carbon ferrochrome produced by the method. A stoichiometric mixture of feed materials including scrap aluminum granules, lime, silica sand, and chromite ore are provided into a plasma arc furnace. The scrap aluminum granules are produced from used aluminum beverage containers. The feed materials are heated, whereupon the aluminum in the aluminum granules produces an exothermic reaction reducing the chromium oxide and iron oxide in the chromite to produce molten low carbon ferrochrome with molten slag floating thereon. The molten low carbon ferrochrome is extracted, solidified and granulated into granules of low carbon ferrochrome. The molten slag is extracted, solidified and granulated into granules of slag.

A master alloy used to produce the steel part and a process for producing a sinter hardened steel part from the master alloy are described. The powdered master alloy having a composition of iron, about 1 to less than 5 weight % C, about 3 to less than 15 weight % Mn, and about 3 to less than 15 weight % Cr, wherein the master alloy comprises a microstructure composed of a solid solution of the alloying elements and carbon, the microstructure comprising at least 10 volume % austenite and the remainder as iron compounds. The process comprises: preparing the master alloy, mixing the master alloy with a steel powder to produce a mixture wherein the weight % of the master alloy is from 5 to 35 weight % of the mixture, compacting the mixture into a shape of a part and sintering the mixture to produce the steel part, and controlling the cooling rate after sintering to produce sinter hardening. The master alloy powder can also be used as a sinter hardening enhancer when mixed with low-alloy steel powders.

Refined niobium-based ferroalloys are provided by removing lead and other impurities therefrom by a process comprising charging niobium ore concentrate and/or niobium oxide or a mixture of niobium oxides to a metallothermic reaction chamber, admixing the ore concentrate and/or niobium oxide with a reducing agent, initiating a metallothermic reaction, under reduced pressure; and allowing the reaction product to solidify and cool; crushing the reaction product or crushing the niobium-based ferroalloy previously reduced in open air, and charging the crushed product to a melting crucible within a vacuum induction melting furnace, lowering the pressure within the furnace to below 1 mbar, and melting the crushed product while vaporizing the impurities contained therein.

Disclosed is a method for manufacturing a lightweight brake disc with maximized heat dissipation ability. The method includes a first step of mixing gray cast iron and FeCr ferroalloy with each other to produce a mixture, melting and solidifying the mixture to cast an alloy; a second step of heat-treating the alloy cast in the first step to pearlitize a microstructure of the alloy; and a third step of performing nitriding heat treatment of the alloy heat-treated in the second step.

An inoculant for the manufacture of cast iron with spheroidal graphite is disclosed, the inoculant has a particulate ferrosilicon alloy having between 40 and 80% by weight of Si; 0.02-8% by weight of Ca; 0-5% by weight of Sr; 0-12% by weight of Ba; 0-15% by weight of rare earth metal; 0-5% by weight of Mg; 0.05-5% by weight of Al; 0-10% by weight of Mn; 0-10% by weight of Ti; 0-10 by weight of Zr; the balance being Fe and incidental impurities in the ordinary amount, wherein the inoculant additionally contains, by weight, based on the total weight of inoculant: 0.1 to 15% of particulate Bi.sub.2S.sub.3, and optionally between 0.1 and 15% of particulate Bi.sub.2O.sub.3, and/or between 0.1 and 15% of particulate Sb.sub.2O.sub.3, and/or between 0.1 and 15% of particulate Sb.sub.2S.sub.3, and/or between 0.1 and 5% of particulate Fe.sub.3O.sub.4, Fe.sub.2O.sub.3, FeO, or a mixture thereof, and/or between 0.1 and 5% of one or more of particulate FeS, FeS.sub.2, Fe.sub.3S.sub.4, or a mixture thereof, a method for producing such inoculant and use of such inoculant.

A method and system for recovering a high yield of low carbon ferrochrome from chromite and low carbon ferrochrome produced by the method. A stoichiometric mixture of feed materials including scrap aluminum granules, lime, silica sand, and chromite ore are provided into a plasma arc furnace. The scrap aluminum granules are produced from used aluminum beverage containers. The feed materials are heated, whereupon the aluminum in the aluminum granules produces an exothermic reaction reducing the chromium oxide and iron oxide in the chromite to produce molten low carbon ferrochrome with molten slag floating thereon. The molten low carbon ferrochrome is extracted, solidified and granulated into granules of low carbon ferrochrome. The molten slag is extracted, solidified and granulated into granules of slag.

A method and system for recovering a high yield of low carbon ferroalloy, e.g., low carbon ferrochrome, from chromite and low carbon ferrochrome produced by the method. A stoichiometric mixture of feed materials including scrap aluminum granules, lime, silica sand, and chromite ore are provided into a plasma arc furnace. The scrap aluminum granules are produced from used aluminum beverage containers. The feed materials are heated, whereupon the aluminum in the aluminum granules produces an exothermic reaction reducing the chromium oxide and iron oxide in the chromite to produce molten low carbon ferrochrome with molten slag floating thereon. The molten low carbon ferrochrome is extracted, solidified and granulated into granules of low carbon ferrochrome. The molten slag is extracted, solidified and granulated into granules of slag.

Refined niobium-based ferroalloys are provided by removing lead and other impurities therefrom by a process comprising charging niobium ore concentrate and/or niobium oxide or a mixture of niobium oxides to a metallothermic reaction chamber, admixing the ore concentrate and/or niobium oxide with a reducing agent, initiating a metallothermic reaction, under reduced pressure; and allowing the reaction product to solidify and cool; crushing the reaction product or crushing the niobium-based ferroalloy previously reduced in open air, and charging the crushed product to a melting crucible within a vacuum induction melting furnace, lowering the pressure within the furnace to below 1 mbar, and melting the crushed product while vaporizing the impurities contained therein.