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.

The present invention concerns the field of refining metal melts or slags and provides in particular a reactive material based on calcium aluminate and carbon, its process of preparation and various methods for refining metal melts using the same.

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.

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.

The present invention relates to a method for obtaining calcium aluminates for metallurgical use from non-saline aluminum slags by means of reactive grinding and thermal treatment.

Ti, N, Al, Mg, and Ca concentrations are controlled in order to prevent aggregation of TiN inclusions. Furthermore, not only is a FeCrNi alloy having superior surface property provided, but also a method is proposed in which the FeCrNi alloy is produced at low cost using commonly used equipment. The FeCrNi alloy includes C0.05%, Si: 0.1 to 0.8%, Mn: 0.2 to 0.8%, P0.03%, S0.001%, Ni:16 to 35%, Cr: 18 to 25%, Al: 0.2 to 0.4%, Ti: 0.25 to 0.4%, N0.016%, Mg: 0.0015 to 0.008%, Ca0.005%, O: 0.0002 to 0.005%, freely selected Mo: 0.5 to 2.5% in mass % and Fe and inevitable impurities as the remainder, wherein Ti and N satisfy % N% Ti0.0045 and the number of TiN inclusions not smaller than 5 m is 20 to 200 pieces/cm.sup.2 at a freely selected cross section.

Ti, N, Al, Mg, and Ca concentrations are controlled in order to prevent aggregation of TiN inclusions. Furthermore, not only is a FeCrNi alloy having superior surface property provided, but also a method is proposed in which the FeCrNi alloy is produced at low cost using commonly used equipment. The FeCrNi alloy includes C0.05%, Si: 0.1 to 0.8%, Mn: 0.2 to 0.8%, P0.03%, S0.001%, Ni:16 to 35%, Cr: 18 to 25%, Al: 0.2 to 0.4%, Ti: 0.25 to 0.4%, N0.016%, Mg: 0.0015 to 0.008%, Ca0.005%, O: 0.0002 to 0.005%, freely selected Mo: 0.5 to 2.5% in mass % and Fe and inevitable impurities as the remainder, wherein Ti and N satisfy % N% Ti0.0045 and the number of TiN inclusions not smaller than 5 m is 20 to 200 pieces/cm.sup.2 at a freely selected cross section.

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.

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 clean and rapid smelting method in an electric arc furnace with full scrap steel, is suitable for smelting process of 30-300 t electric arc furnace with full scrap steel. In the smelting process of the electric arc furnace with full scrap steel, different kinds of mediums are injected by an injection lance which is installed inside refractory material of sidewall at the bottom of the electric arc furnace in different stages of smelting. Carburization is utilized in molten pool to accelerate melting down and improve carbon content of the molten pool at the stage of recarburizing and fluxing. A reaction in the molten pool is intensified at the stage of high efficiency dephosphorization and deep denitrogenation, to enhance efficient dephosphorization and deep denitrification of the reaction in the molten pool, thereby accelerating the smelting speed of the electric arc furnace with full scrap steel, improving effect of dephosphorization and denitrification.