US 5,286,277 AGranted

Method for producing steel

AssigneeZaptech Corporation

InventorsRafik Aizatulov, Grigori Galperine, Gregory Gitman, Jakov Grenader, Boris Kustov

Life of this patent

Estimating the term…

Loading patent…

Abstract

A steelmaking process is disclosed utilizes solid ferrous metallic material as a substantial part of the metallic charge and uses heat released by combustion of two different types of carbonaceous materials and steel scrap that have been strategically charged inside of at least a partially refractory lined steelmaking vessel. One of the carbonaceous materials contains a high content of volatile hydrocarbons and is primarily responsible for early preheating and partial melting of the solid ferrous material. The second carbonaceous material contains a low content of volatile hydrocarbons and is primarily responsible for providing a reducing capability to the slag, for carburizing the melt and for providing additional heat generated by combustion which is used to enhance heating and melting of solid ferrous materials. This method of steelmaking also consists of the controllable introduction of oxygen rich oxidizing gas which initially is used for combustion of said hydrocarbons in the carbonaceous materials to melt solid ferrous metallic material and further is used for refining the resultant molten pool of ferrous material before tapping. Slag forming material is used at the bottom of the furnace to provide for continuous refining of molten ferrous material throughout entire steelmaking process. Molten blast furnace ("hot") iron also can be charged in an embodiment of this method of steel production. Electrical energy may be used as an additional heat source to increase the metallic yield.

Claims126

Dependent claims

A method of steelmaking, conducted in an at least partially refractory-lined furnace, comprising the steps of:

(a) introducing a first basic slag forming material into the furnace;
(b) then charging a first solid carbonaceous material including volatile hydrocarbons;
(c) then charging on top of previously charged materials at least a fraction of a solid ferrous metallic material;
(d) then preheating at least a part of said fraction of the metallic material charged in the preceding step by a process comprising the substeps of:
i. blowing a controllable flow of oxidizing gas toward said charged solid ferrous metallic material with a lancing means having a tip for directing the flow of oxidizing gas, wherein the tip is positioned above said solid ferrous metallic material charged in the preceding step;
and
ii. essentially simultaneously with said blowing substep, charging continually on top of said solid ferrous metallic material a controllable amount of at least a second solid carbonaceous fuel material including a higher average concentration of volatile hydrocarbons than said first solid carbonaceous material;
wherein said second solid carbonaceous fuel material is at least partially combusted to preheat the fraction of said solid ferrous metallic material charged in the preceding step;
(e) then burning a first portion of the preheated ferrous metallic material in a central zone of the furnace to release additional heat to melt at least a second portion of the preheated solid ferrous metallic material located in an area remote from the central zone, while protecting said second portion from oxidation;
(f) accumulating molten ferrous metal at the bottom of the furnace;
(g) at least partially refining and at least partially superheating said accumulated molten ferrous material above the melting point by a process including the substeps of:
i. charging additional basic slag forming material into the furnace;
and
ii. blowing additional oxidizing gas with said lancing means;
and
(h) tapping off said molten ferrous metal and at least a part of a resulting slag material after the desired tap temperature is reached.

13 more elements

A method of steelmaking, conducted in an at least partially refractory-lined furnace, comprising the steps of:

(a) charging a charge of solid ferrous metallic material into the furnace;
(b) preheating said solid ferrous metallic material by a process comprising the substeps of:
i. charging a first hot molten ferrous metallic material into the furnace;
ii. blowing a controllable flow of oxidizing gas toward said solid ferrous metallic material with a lancing means having a tip for directing the flow of oxidizing gas, wherein the tip is positioned above said solid ferrous metallic material charged in the previous step;
and
iii. essentially simultaneously with said blowing substep, charging continually on top of said solid ferrous metallic material a controllable amount of a solid carbonaceous material comprising volatile hydrocarbons, wherein said solid carbonaceous material is at least partially combusted to preheat the said solid ferrous metallic material charged in the previous step;
(c) then burning a first portion of the preheated ferrous metallic material in a central zone of the furnace to release additional heat to melt at least a second portion of the preheated solid ferrous metallic material while protecting said second portion from oxidation, thereby creating a second molten ferrous metallic material and wherein the burning step further comprises the substeps of:
i. directing the flow of oxidizing gas towards a central zone of the furnace;
and
ii. moving the tip of the lancing means closer to the bottom of the furnace;
(d) accumulating a mixture comprising partially oxidized first hot molten ferrous metallic material and the second molten metallic material at the bottom of the furnace;
(e) at least partially refining and at least partially superheating said accumulated mixture up to a predetermined tap temperature by a process including the substeps of:
i. charging a first charge of basic slag-forming material, thereby forming a slag;
and
ii. blowing additional oxidizing gas with said lancing means to produce a partially refined molten ferrous product;
and
(f) tapping off the at least partially refined molten ferrous product and at least a part of the slag after the desired tap temperature is reached.

14 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/889,018Filed 26 May 1992
Granted: 15 Feb 1994
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

C21C 5/562
Manufacture of steel by other methods: starting from scrap
C21C 5/35
Regulating or controlling the blowing: blowing from above and through the bath
C21C 5/5217
In an alternating current [AC] electric arc furnace: equipped with burners or devices for injecting gas, i.e. oxygen, or pulverulent materials…
C21C 2007/0093
Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00: duplex process; Two stage processes