WO2015041834A2

WO2015041834A2 - Steel production in a coke dry quenching system

Info

Publication number: WO2015041834A2
Application number: PCT/US2014/053366
Authority: WO
Inventors: Michael P Barkdoll
Original assignee: Forest Vue Research
Priority date: 2013-09-17
Filing date: 2014-08-29
Publication date: 2015-03-26
Also published as: JP2016536468A; WO2015041834A3

Abstract

A method for reducing an iron-containing material to a metalized iron product. The method includes feeding from about 5 to about 25 percent by weight, based on a total weight of iron-containing material having a total iron content of from about 60 to about 85 % by weight and hot coke to a coke dry quenching (CDQ-SP) apparatus. The iron-containing material is reduced in the CDQ-SP apparatus to metalized iron product having a degree of metallization of greater than about 90 % by weight. The metalized iron product is then separated from a quenched coke product.

Description

STEEL PRODUCTION IN A COKE DRY QUENCHING SYSTEM TECHNICAL FIELD:

[0001] The present disclosure relates to a method for reducing an iron-containing material to an enriched iron-containing product or metalized iron and in particular to iron and steel production within a coke dry quenching (CDQ) system.

BACKGROUND AND SUMMARY:

[0002] The industrial process of metallurgical coke production is a batch process starting with coal blending, then coke production in coke ovens, coke oven gas treatment and finally, coke cooling. Coke is "pushed" from coke ovens at a temperature of 1000 - 1100°C as incandescent coke. The incandescent coke must be cooled rapidly to prevent combustion and hence product loss. One of two methods of rapid coke cooling (aka, coke quenching) is typically employed. One method is wet quenching wherein the incandescent coke is deluged with water and cooled rapidly. Another method known as coke dry quenching (CDQ), illustrated schematically in FIG. 1, employs a large refractory vessel (or chamber) 10 where incandescent coke is loaded into the top 16 of the vessel 10 using a vessel charging bucket 12. As the coke flows down through the vessel 10, the coke is cooled by a counter-current flow of an inert gas 22. The sensible heat within the coke is recovered from the coke produces steam and ultimately the steam drives a steam turbine generator to produce electrical power. The cooled coke 34 exits the bottom 20 of the vessel 10 and is conveyed by conveyor 36 to a product area. While wet quenching is still the predominant coke cooling process, rapid expansion has occurred in deploying CDQ systems.

[0003] The "driving force" for use of CDQ systems for coke quenching, include, but are not limited to, environmental reasons (i.e., .reduced dust/VOC/S0₂ emissions), improved stability of coke, and energy efficiency (i.e. C0₂ free power production).

[0004] In view of the foregoing, embodiments of the disclosure provide a method for reducing an iron-containing material to a metalized iron product. The method includes feeding from about 5 to about 25 percent by weight, based on a total weight of iron-containing material having a total iron content of from about 60 to about 85 % by weight and hot coke to a coke dry quenching (CDQ-SP) apparatus. The iron-containing material is reduced in the CDQ-SP apparatus to metalized iron product having a degree of metallization of greater than about 90 % by weight. The metalized iron product is then separated from a quenched coke product.

[0005] The present disclosure describes an innovative process wherein a steel mill waste product, namely mill scale, may be introduced into the CDQ along with the incandescent coke to simultaneously produce coke and steel products. Given the conditions that exist within the CDQ, namely high initial temperature (1000 - 1100°C), substantial concentrations of carbon monoxide (CO) and hydrogen (H₂) present in the inert recycle gas, and the long residence time (approximately 5 hours), the mill scale will be reduced to steel. The value of the steel produced may be equated to the typical value of scrap steel. At a 10% feed rate of mill scale and 90% feed rate of incandescent coke, a 2 million metric tons per year CDQ can process 225,000 metric tons per year of mill scale and can produce 180,000 metric tons per year of steel. Note the mill scale (oxides of iron) to steel production nominally has a yield of 80%> by weight.

[0006] An advantage of the CDQ process for simultaneously producing steel and coke is that net C0₂ emission rates may be significantly reduced, while power production rates are reduced less than 0.5%>.

[0007] In this disclosure the following terms are defined as follows:

[0008] "Mill Scale" refers to the waste product generated primarily in steel mill rolling operations of slabs, billets, sheets or shapes. It is the "flaky surface" formed by the surface oxidation that forms on hot rolled steel. It is a mixture of metallic iron and iron oxides consisting of iron (11,111) oxide, hematite, magnetite and wustite and carbon. Mill scale typically contains 0.5 wt.% or less carbon and 95 wt.% total iron in the form of iron oxides, primarily FeO, Fe₂0₃, and Fe₃0₄.

[0009] "CDQ Recirculation Gas" is the inert gas used to cool coke in a CDQ reactor and consists of: 10% to 15% C0₂; 8% to 10% CO; 2% to 3% H₂, and 70% to 75% N₂.

[0010] "Iron Rich Material" is any source of iron for iron or steel production including manmade materials and naturally occurring materials. Iron Rich Materials may include, but are not limited to: iron ore fines, thermally processed EAF dust, mill scale, blast furnace dust, sinter plant fines, iron ore pellets and lump iron ore.

[0011] "Electric Arc Furnace (EAF)" is a steelmaking furnace in which scrap metal is generally 100% of the charge. Heat is supplied from electricity that arcs from graphite electrodes into the metal bath. EAFs may utilize either alternating current (AC) or direct current (DC). [0012] "Blast Furnace (BF)" is a tall cylindrical, refractory lined furnace used for the production of pig iron or hot metal for the direct conversion to steel. Primary inputs are iron ore (pellets, sinter or lump), coke, limestone and hot air (1000 - 1100°C). Secondary inputs are pulverized coal, natural gas or coal tar.

[0013] "Sinter Plant" is a facility in which iron ore is crushed, homogenized and mixed with limestone and coke fines and then cooked (sintered) to form sinter.

[0014] "Basic Oxygen Furnace (BOF)" is a facility used for a method of primary steelmaking in which carbon-rich molten pig iron is made into steel. Blowing oxygen through the molten pig iron lowers the carbon content of the alloy and changes it into low carbon steel. It is also known as Basic Oxygen Steelmaking (BOS), Basic Oxygen Process (BOP), LD Converter and Oxygen Steelmaking (OSM).

[0015] "Pig Iron" is the intermediate product of smelting iron ore with a high carbon fuel such as coke, usually with limestone as a flux. Pig iron has a very high carbon content, typically 3.5 to 4.5%, along with silica and other constituents of dross which make it very brittle and not very useful directly.

[0016] "Steel" is an alloy of iron and other elements including carbon. When carbon is the primary alloying element, its content in the steel is between 0.002% and 2.1% by weight.

[0017] "Mild and Low Carbon Steels" are the most common forms of steel. Low carbon steel contains approximately 0.05 to 0.3% carbon and mild steel contains 0.3% to 0.6% carbon.

[0018] "Hot Metal" is a term used to describe the molten metal product from either an

EAF or BF. A typical metric to describe a unit operation is x lbs. of C0₂ emitted per ton of hot metal produced.

[0019] "CDQ-SP" is Coke Dry Quenching - Steel Production.

[0020] "Metalized" and "metallization", as used throughout this specification does not mean coated with metal, but means nearly completely reduced to the metallic state, i.e., always in excess of 60 wt.% metal, and usually in excess of 80 wt.% metal in the material. In the case of "metalized iron", the term "metalized" means the percent of total iron present as metallic iron (Fe). Percent metallization is determined by the equation:

wt. % metallization = (wt. metallic iron( valence 0) / wt. total iron (all valence states)) X 100. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Embodiments of the disclosure may be understood by reference to the following drawings wherein:

[0022] FIG. 1 is a schematic diagram of a prior art CDQ system.

[0023] FIG. 2 is a schematic block flow diagram showing how mill scale is currently processed in a prior art integrated steel mill.

[0024] FIG. 3 is a schematic diagram of a CDQ-SP system according to an embodiment of the disclosure for co-producing cooled coke and low carbon steel.

[0025] FIG. 4 is a schematic block flow diagram showing how mill scale can be utilized in the CDQ-SP system to produce low carbon steel in an integrated steel mill.

[0026] FIG. 5 is a bar chart comparing C0₂ intensity from scrap mini-mills (EAF) and integrated mills (BF - BOF route).

DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0027] To those schooled in the art, the production of iron by reduction utilizing either

CO or H₂, or both, at elevated temperatures (i.e. 1400°F plus) is well known and has been known for centuries (i.e. iron age, 1300 BC to 500 AD). However, the hunt for cost effective, environmentally conscious iron reduction processes continues even today with a veritable plethora of significant research and research dollars spent on devising new methods. As an example, the HIsmelt process was developed at considerable expense and is a direct iron ore to pig iron process that does not use metallurgical coke, and which has not been proven to be commercially viable.

[0028] The list of alternative iron making processing routes is quite extensive. The only three processes to achieve significant commercial success are: MIDREX -Direct Reduced Iron (DRI); HYSLA - DRI, and SLRN - sponge iron.

[0029] MIDREX and HYSAL are very similar natural gas based DRI processes. Both have high capital cost and require low cost natural gas and pelletized or lump ore to be commercially viable.

[0030] The SLRN sponge iron process utilizes non-metallurgical coal and lump or pelletized ore. The sponge iron processes have achieved most of their success in India where low grade coal (high ash content) and lump ore are readily available. [0031] The COREX process has achieved limited commercial success. It is a non- metallurgical coal (with some coke added) based direct smelting process. Pelletized and/or lump ore is required. The process is very capital intensive and mechanically complex.

[0032] Various other "alternative iron making processes" which have been investigated intensely but have not achieved commercial success are: ROMELT; HISMELT; DIOS; AUSMELT; TECHNORED; AND FINMET.

[0033] As is evidenced by the foregoing brief summary, it is apparent that any environmentally benign highly cost effective alternative iron making process may gain the immediate attention of major steel producers.

[0034] The current process (CDQ-SP) may meet all the criteria for a successful process given the following attributes: extremely low capital cost by using an existing process namely, CDQ; can process steel mill wastes (mill scale, BF dust, BOF dust, etc.); makes a high quality product, namely steel; has extremely low or no raw material costs (i.e. recycled mill scale); and C0₂ (greenhouse gas) generation is reduced.

[0035] Before proceeding with a detailed description of the CDQ-SP process according to an embodiment of the disclosure, it may be useful to describe the preferred raw material (mill scale) and the end product. Mill scale is generated primarily in the casting and rolling mill operations in a steel mill. Mill scale is actually high grade steel flakes and particles that have been oxidized during the casting and rolling operation for making steel. Because mill scale arises from steel processing, it has little or no contaminants (gangue) that naturally occur in iron ore (BF and BOF route) or that may be found in scrap metal (EAF route). Physically, mill scale is described as flaky oxidized steel fines. The size of mill scale typically ranges from 0.6 cm by 0 cm wherein 50 to 60 wt.% is greater than about 0.16 cm with the remainder less than 0.16 cm down to -100 microns. Typical mill scale has the following composition:

Total iron - 65% to 80% (balance 0₂)

Fe° (iron) - 0% to 10%

Fe⁺² (wusite) - 50% to 70%

Fe⁺³ (hematite) - 20% to 40%, and

Carbon - typically less than 0.75%>.

[0036] Mill scale is generated at a rate of 1.5 wt. % to 5.0 wt. % of crude steel produced.

Generation rates of mill scale are highly plant specific with slab plants having the lowest generation rates and hot rolled sheet/long products having the highest generation rates. The product from the CDQ-SP process is highly metalized steel with minimal contaminants and low to extra carbon content. The CDQ-SP process may produce steel (not molten) fines with the following chemical composition:

Fexotai 99+ wt. %

Fe° (metallic iron) 95+ wt. % and

Carbon 0.05 - 0.5 wt.%.

[0037] The physical form of the product steel fines may be essentially unchanged from the feedstock mill scale.

[0038] The highly metalized steel product may be suited for direct substitution of scrap into a Basic Oxygen Furnace (BOF), as shown in FIG. 4, or may go to an Electric Arc Furnace (EAF) for direct melting to crude steel. Either route will result in significant C0₂ reduction and economic benefit to steel mill operators.

[0039] We will now turn back to the presentation of CDQ and CDQ-SP process descriptions, starting with a brief outline of the CDQ process (FIG. 1). Incandescent coke (1000 - 1100°C) is "pushed" out of the coke oven into the vessel charging bucket 12. In more modern plants the bucket 12 rotates to ensure a homogenous particle size distribution of the coke. The bucket 12 is transferred to the CDQ facility where it is hoisted by an overhead crane assembly 14 and then transferred horizontally to the top 16 of the CDQ vessel 10, where it is emptied into the CDQ vessel pre-chamber 18. Subsequently, as cooled coke 34 is withdrawn from the bottom 20 of the CDQ vessel 10, the recently deposited coke in the pre-chamber 18 begins its descent downward through the refractory lined CDQ vessel 10. Simultaneously, an inert gas stream 22 is directed up through the CDQ vessel thereby absorbing sensible heat from the coke. The heated gas (approximately 800 - 900°C) is then routed to a primary dust collector (multi-clone) 24 and then to the inlet of a heat recovery steam generator (HRSG) 26, also known as a waste heat boiler. The cooled gas from the HRSG 26 is then routed to a secondary dust collector 28 (baghouse) and then onto a high pressure gas recirculating fan 30. Downstream from the fan, an additional heat exchanger 32 is deployed to further cool the recirculated gas and pre-heat boiler feed water. The steam generated in the HRSG 26 may be routed to a steam turbine generator for electrical power production or routed as steam to the steel mill for process steam. The nominal power generation rate for a CDQ process (FIG. 1) (i.e. 100% steam utilization for power) is typically 0.15 - 0.18 net MW per TPH coke cooling throughput. The recirculation gas has a nominal composition of: 10 to 15 vol. % C0₂; 8 to 10 vol. % CO; 2 to 3 vol. % H₂ (peaks to 10 vol. %); and 70 to 75 vol. % N₂.

[0040] Typically a CDQ plant is made up of multiple CDQ vessels 10 each with a cooling capacity of ~60 tons per hour (TPH). More recently, large CDQ vessels 10 have been introduced with cooling capacities of up to 200 TPH. It should be noted that the dry quenched coke 34, having extremely low moisture content (less than 0.5%), is routed directly to a screening plant by a conveyor 36 for removal of coke fines (i.e. coke breeze). Typical screened sizes are furnace coke at plus 1.9 cm or 2.54 cm and coke breeze minus 1.9 cm or 2.54 cm. The furnace coke is sent directly to the BF while the coke breeze may be further screened into "nut coke" (typically 0.8 cm x 2.54 cm) which also reports to the BF, while the fines (minus 0.8 cm) are routed to the sinter plant.

[0041] FIG. 2 is a schematic drawing of a prior art material flow for an integrated steel plant 50. As shown in FIG. 2, a sinter plant 52 receives mill scale 54 from a continuous casting or rolling mill 56, fine ore 58 and other raw materials 60 such as lime and clay to produce sinter 62 that is fed along with metallurgical coke 64 made from metallurgical coal 66 in a coking plant 68 and iron ore 70 to a blast furnace 72. The fines collected by the primary and secondary dust collectors 24 and 28 in the CDQ plant (FIG. 1) are also typically routed to a sinter plant 52. From the blast furnace 72, the product 74 is desulfurized in a desulfurization plant 76 to provide pig iron 78 that is fed to a steelmaking plant 80. Crude steel 82 from the steelmaking plant 80 is then routed to the casting or rolling mill 56 wherein the final product 90 is produced.

[0042] Inspection of FIG. 2 shows not only the long, complex process path for mill scale

54 to crude steel 82, but it should also be noted that the sinter plant 52 has an extremely high recycle rate (i.e. 275 to 550 kg per 870 kg finished sinter 62). The high recycle rate means that on average one half the feed stock to the sinter plant has to be re-processed before it is of sufficient size and strength to go to the BF.

[0043] In the CDQ-SP process according to an embodiment of the disclosure, as shown in FIG. 3, mill scale 54 (FIG. 4) preferably (or other iron rich materials such as iron ore concentrate, iron ore pellets, lump ore, etc.) may be introduced into the CDQ process (FIG. 3) at any one of three locations in the coking plant 68 instead of in the sinter plant 52. The first location is the bottom of the coke bucket 12 prior to pushing incandescent coke from a coking plant 68 (FIG. 4) into the coke bucket 12. The second location is on top 100 of the incandescent coke in the coke bucket 12 (FIG. 3) and the third is the pre-chamber 18 of the CDQ vessel 10. More than likely plant operators will prefer the first location from a materials handling standpoint. However, the second location affords an additional attribute in that mill scale on top of the incandescent coke protects the coke from excessive burn loss during transport to the CDQ- SP.

[0044] Regardless of the introduction location, the heat transfer rate from the incandescent coke to the mill scale will be extremely high and may raise the temperature of the mill scale above the reduction temperature (800 - 850°C) even before the mixture exits the pre- chamber 18 and is exposed to the CO and H₂ reducing gases in the chamber 10 (FIG. 3). The fine mill scale has a very high specific surface area meaning that not only will heat transfer occur rapidly (i.e. in minutes), but also gas to solid contact will be excellent and lead to the rapid reduction of the iron oxides in the mill scale thereby producing steel. The CDQ-SP vessel 10 has other very positive attributes for the reduction of mill scale to steel, namely: long residence time to complete oxide to metallic iron reduction; the reduced iron (steel) may always be "bathed" in a reducing atmosphere hence there is no potential for re-oxidation of the steel; and sufficient CO and H₂ within the recirculation gas 22 to complete the reduction process. Accordingly, the metalized steel product 102 from the CDQ-SP (FIG. 3) in the coking plant 68 may be directly fed to the steelmaking plant 80 (FIG. 4).

[0045] It should be noted that one of the driving principles of the operation of a CDQ system is to ensure that permeability of the bed is sufficient so as to not put too much back pressure on the gas recirculation fan 30. The CDQ-SP process envisions the introduction of mill scale at rates from 5 wt.% to 25 wt.% of the coke feed rate and preferably 10 wt. % to 15 wt.% of a total weight of coke fed to the CDQ vessel. Because of the extreme differences in bulk density between coke at -480 kg/m³ and mill scale at about 2560⁺ kg/m³, the volumetric decrease in the coke/mill scale bed, at a 10 wt.% mill scale rate, is only 2 vol. %, thereby ensuring no impact on gas recirculation rates.

[0046] It should also be noted that the CO and H₂ in the recirculation gas may arise from different sources. The CO arises primarily from air drawn into the system during charging of incandescent coke into the pre-chamber 18. The 0₂ in the infiltration air partially combusts coke and forms CO and C0₂. The H₂ arises from the final dehydrogenation reactions that occur in coke production. Hence the earlier comment about peaks of H₂ to 10 vol.% can be attributed to coke introduction that has not been completely "coked out", sometimes referred to as green coke. If a facility desires to process more mill scale than the aforementioned 10 to 15 wt.% of total feed rate, insufficient reducing gas limits may be approached. In this regard there are several readily available reducing gas streams that may be used to ensure sufficient iron production. Such reducing gas streams include, but are not limited to: basic oxygen furnace gas - 70 to 80 vol.% CO; blast furnace gas - 20 vol.%> CO; and coke oven gas - 6 vol. % CO and 63 vol.%> H₂.

[0047] Subsequent to the reduction to steel in the CDQ-SP process, product recovery is very straightforward. Since the steel produced is all in the form of fines, the steel may be separated in the coke screening plant and will be easily recovered via electro-magnets deployed in the coke breeze. It should be noted that the temperatures within the CDQ-SP process are sufficiently low to prevent any steel melting and/or agglomeration. For example, the melting point of mild steel is 1430°C and the incandescent coke introduced into the CDQ-SP vessel 10 has a maximum temperature of 1000 - 1100°C.

[0048] One other concern about steel production in the CDQ-SP is that such co- production of steel and coke might degrade the power generation rate due to heat loss either during iron production or steel discharge. These concerns are very minimal in scope. Concerning heat loss during iron oxide to iron (steel) reduction, if the reduction is driven by CO, the reaction is exothermic as follows: FeO + CO Fe + C0₂ (+6900 Btu/lb). If the reaction is driven by H₂ reduction, the reaction is endothermic as follows: FeO + H₂ Fe + H₂0 (-10,850 Btu/lb). Since the recirculation gas in the CDQ-SP reactor is predominantly CO, it may be said that no degradation of power production will occur. In fact a slight increase in power production may occur. Sensible heat transferred from coke to the mill scale and steel is a very minor amount because most of the heat is released back into the gas stream as the coke and steel cools. Calculations have shown that the decrease in CDQ-SP power production is less than 0.5%> due to sensible heat transferred from coke to the mill scale.

[0049] Based on the foregoing analysis, the CDQ-SP process is technically sound.

Turning to economic and environmental considerations, the positive attributes are highlighted by the following calculations and clarifications. [0050] Perhaps the best method for presenting the economic analysis is via a case study.

Economics for larger and smaller plants may be determined from this case by applying simple ratios. Material flows are illustrated in FIGs 2 and 4.

Given: · Mill scale generation 15 - 50 kg/tonne crude steel

• Mill scale to steel yield 80%

• External scrap/metallics to BOF = 115 kg per tonne crude steel

• 0.344 Tonnes coke used to produce a tonne of crude steel Assume: · Coke production 1,000,000 tonnes/yr

• 15 wt. % Mill scale to CDQ-SP

Find: Crude steel production:

1,000,000 TPY Coke ÷ 0.344 tonnes coke per ton crude steel = 2,900,000 TPY Crude steel.

[0051] Find: Mill scale production:

2,900,000 TPY crude steel x 15 to 50 kg mill scale per tonne crude steel = 44,000 to 145,000 TPY Mill scale.

[0052] Find: External scrap/metallics to BOF:

115 kg per tonne crude steel x 2,900,000 TPY crude steel = 334,000 TPY External scrap/metallics to BOF.

[0053] Using the 2/3 's rule for estimating purposes, the steel production from the CDQ-

SP process is: (145,000 - 44,000) x 0.67 +44,000 = 112,000 TPY Mill scale.

[0054] At an 80% yield this then equals: 112,000 TPY x 0.80 = 90,000 TPY steel.

[0055] This then represents: 90,000 TPY ÷ 334,000 TPY x 100 = 27 wt.% of scrap needed for the BOF.

[0056] Also at these rates, the wt. % mill scale to the CDQ-SP process is: 112,000 TPY mill scale ÷ (1,000,000 TPY coke + 112,000 TPY mill scale) = 10 wt. %

[0057] Note: If mill scale other than mill scale recirculated from the casting/rolling mill

56 were used, the processing rate could easily be increased economically to 15 wt.% of total feed rate to the CDQ-SP.

[0058] If additional mill scale is used and processed through the CDQ-SP, additional gross savings may be realized as follows. At a 15 wt. % feed rate to the CDQ-SP vessel 10, 175,000 TPY of mill scale may be processed. Since 112,000 TPY of internal mill scale is available: (175,000 TPY total - 112,000 TPY internal) = 63,000 TPY additional mill scale. [0059] With the use of additional mill scale, steel production in the CDQ-SP is: 175,000

TPY mill scale x 0.80 yield = 140,000 TPY steel.

[0060] Note: Additional iron ore is required to replace mill scale diverted from the sinter plant 52 to the CDQ-SP.

[0061] Another stated attribute of the CDQ-SP process is C0₂ emission reduction. C0₂ intensity (i.e. tonnes C0₂ per tonne crude steel) emission estimates can be quite complex, especially in integrated mills. The major sources of C0₂ emission in an integrated mill are the BF, power plant, sinter plant and coke plant. It is noteworthy that the BOF is a minor contributor to C0₂ emissions. Given that a CDQ and CDQ-SP are also minor C0₂ emission sources, then the proposed CDQ-SP has an extremely low C0₂ intensity.

[0062] Another way to look at the C0₂ intensity is via FIG. 5. In this drawing the overall

C0₂ intensities for the BF to BOF route and EAF route are presented. Using the data from FIG 5, the C0₂ reduction via the CDQ-SP process may be calculated as shown below.

[0063] The 15 wt. % fed rate of mill scale to the CDQ-SP process produces 140,000 TPY essentially C0₂ free steel. If this much steel was produced via the BF to BOF route, the annual C0₂ emissions would be: 140,000 TPY x (2.1 to 2.5) TPY C0₂ per tonne crude = 294,000 to 350,000 TPY

[0064] It is reported in the literature that a 1,000,000 TPY CDQ system reduces C0₂ emissions (i.e. C0₂ free power) by approximately 300,000 TPY. It is then noteworthy that a CDQ-SP more or less doubles the C0₂ emission rate reduction over a simple CDQ system. C0₂ emission reduction via the CDQ system is one of the strong commercial attributes of the CDQ process. Therefore doubling the C0₂ reduction via the CDQ-SP process is a major driver for implementation.

[0065] In summary, it may be said that the CDQ-SP process: is technically sound; shows extremely favorable economics; and reduces greenhouse gas (C0₂) emissions.

[0066] One final economic analysis is in order. Essentially all that is required for production of steel in a CDQ-SP process is a material handling system to introduce mill scale into the CDQ and a simple electro-magnetic system for recovering the produced steel from the coke fines.

[0067] The description and illustration of one or more embodiments provided in this application are not intended to limit or restrict the scope of the invention as claimed in any way. The embodiments, examples, and details provided in this application are considered sufficient to convey possession and enable others to make and use the best mode of claimed invention. The claimed invention should not be construed as being limited to any embodiment, example, or detail provided in this application. Regardless of whether shown and described in combination or separately, the various features (both structural and methodological) are intended to be selectively included or omitted to produce an embodiment with a particular set of features. Having been provided with the description and illustration of the present application, one skilled in the art may envision variations, modifications, and alternate embodiments falling within the spirit of the broader aspects of the general inventive concept embodied in this application that do not depart from the broader scope of the claimed invention.

Claims

What is claimed is:

1. A method for reducing an iron-containing material to a metalized iron product comprising:

feeding from about 5 to about 25 percent by weight, based on a total weight of iron-containing material having a total iron content of from about 60 to about 85 % by weight and hot coke to a coke dry quenching (CDQ-SP) apparatus;

reducing the iron-containing material to the metalized iron product having a degree of metallization of greater than about 90 % by weight; and

separating the metalized iron product from a quenched coke product.

2. The method of claim 1, wherein the iron-containing material comprises metallic iron and iron oxides, wherein the iron oxides are selected from the group consisting of iron (11,111) oxide, hematite, magnetite and wustite.

3. The method of claim 1, wherein the iron-containing material comprising mill scale.

4. The method of claim 1, wherein the hot coke comprises metallurgical coke.

5. The method of claim 1, further comprising reducing an emission of carbon dioxide from the coke dry quenching apparatus to the atmosphere to less than an amount of carbon dioxide emission to the atmosphere from enriched iron-containing product made in a blast furnace system.

6. The method of claim 1, wherein the iron-containing material is reduced in the presence of a reducing gas selected from the group consisting of hydrogen, carbon monoxide, and mixtures thereof.

7. The method of claim 1, wherein the metalized iron product has a degree of metallization of greater than 95 percent by weight.

8. The method of claim 1, wherein the metalized iron product has a degree of metallization of greater than 98 percent by weight.

9. The method of claim 1, wherein the amount of iron-containing material fed to the CDQ-SP apparatus ranges from about 10 to about 15 percent by weight based on a total weight of iron- containing material and hot coke.

10. The method of claim 1, wherein the iron-containing material is fed into a charging bucket of a CDQ-SP apparatus.

11. The method of claim 1 , wherein the iron-containing material is reduced at a temperature below a melting point of mild steel.

12. The method of claim 1, wherein the enriched iron-containing product is separated from the quenched coke product using an electromagnet.