Straight-grate pelletizing apparatus and production method

Abstract

The present invention relates to a straight-grate pelletizing apparatus (1) configured for production of oxidized iron containing agglomerates (4). An induration arrangement (3) is configured to oxidize an iron oxide containing agglomerates (2) comprising magnetite into said oxidized iron containing agglomerates (4). An induration-cooler transition zone (TZ) comprises an agglomerate discharge section (6) and an agglomerate charge section (8). A gaseous fluid (11) is fed through a travelling grate member (7) in updraft mode at the agglomerate charge section (8) for cooling the material (4), wherein the gaseous fluid (11) is heated and subsequently fed through the travelling grate member (7) in downdraft mode at the agglomerate discharge section (6). The induration-cooler transition zone (TZ) comprises at least one gas inlet device (13', 13'', 13''') is adapted for injecting an oxygen containing gas (15) into the gaseous fluid (11) for targeting the iron oxide containing agglomerates (2) subject to oxidization. The present invention also relates to a method of production of oxidized iron containing agglomerates (4).

Description

[0001] Straiqht-qrate and method

[0002] TECHNICAL FIELD

[0003] The present invention relates to a straight-grate pelletizing apparatus configured for production of oxidized iron containing agglomerates.

[0004] The present invention further relates to a method of production of the oxidized iron containing agglomerates.

[0005] The present invention further relates to a data program, programmed with a program code adapted for causing the straight-grate pelletizing apparatus to execute the method.

[0006] The present invention may concern the mining industry and / or the iron ore oxide production industry and / or the iron material making industry.

[0007] The present invention may concern metallurgical process industry producing oxidized iron containing pellets, such as iron oxide agglomerates or other types of iron ore oxide material.

[0008] The present invention also may concern manufacturers and suppliers of straightgrate pelletizing apparatuses.

[0009] BACKGROUND

[0010] Oxidized iron containing pellets are produced by different types of straight-grate pelletizing apparatuses configured to indurate (oxidize and sinter) dried iron containing pellets (so called green pellets).

[0011] Current straight-grate pelletizing apparatuses provide that the indurated iron containing pellets are formed into oxidized iron containing pellets, which are cooled down in a cooling zone of a cooler device and subsequently distributed from the straight-grate pelletizing apparatuses for transportation to steel producers.

[0012] The straight-grate pelletizing apparatus is configured to move iron containing pellets by means of a travelling grate member, such as a continuous grate, through different zones for drying, induration and cooling. Traditional methods of production of oxidized iron containing pellets by means of a straight-grate pelletizing apparatus, where crude iron ore from the mine is upgraded by several steps, such as including grinding, crushing, sizing and balling is introduced into the straight-grate pelletizing apparatus, include a following step of drying, induration and cooling.

[0013] The induration may be defined as a process provided to oxidize and sinter the iron containing pellets, wherein oxidizing of magnetite of the iron containing pellets generally takes place in a pre-heating zone and eventually to some extent in a firing zone of the induration arrangement. Subsequently, the sintering of the iron containing pellets generally takes place in an after firing zone (may comprises a first after firing zone and a second after firing zone). The oxidizing of magnetite of the iron containing pellets into hematite generates heat that may be used for the sintering process. Subsequently, the indurated iron containing pellets are transferred to a cooling arrangement configured to cool down the indurated iron containing pellets. In the current straight-grate pelletizing apparatus, the sintering thus mainly may take place in the firing zone and in the after firing zone for increasing the strength and metallurgical properties of the oxidized iron containing pellets.

[0014] Known straight-grate pelletizing apparatuses adapted for production of oxidized iron containing agglomerates may use a gaseous fluid transfer line arrangement for circulating a gaseous fluid, such as a process gas or heated air, through the preheating zone for oxidizing the magnetite of the iron containing pellets.

[0015] However, the known straight-grate pelletizing apparatuses may be energy consuming and / or may produce oxidized iron containing pellets having adversely affected properties and quality. Prior art straight-grate pelletizing apparatuses may produce large amount of CO2 and other non-environmental exhaust gases.

[0016] A further problem with straight-grate pelletizing apparatuses of today is that they may not optimize the recovery of exhaust heat.

[0017] A yet further problem with prior art straight-grate pelletizing apparatuses is that they may produce dust emissions due to insufficiently oxidized iron oxide containing agglomerates. A yet further problem with prior art straight-grate pelletizing apparatuses is that they may produce insufficiently oxidized iron oxide containing agglomerates, adversely affecting the quality of the produced oxidized iron containing agglomerates.

[0018] Furthermore, one problem with straight-grate pelletizing apparatuses of today may be that they involve relatively low production rate relative prior art for production of oxidized iron containing agglomerates.

[0019] SUMMARY OF THE INVENTION

[0020] There is an object to provide a straight-grate pelletizing apparatus and a method of production of oxidized iron containing agglomerates by means of the straight-grate pelletizing apparatus, wherein the production rate for production of oxidized iron containing agglomerates is increased relative prior art productions rates of current straight-grate pelletizing apparatuses.

[0021] There is an object to provide a straight-grate pelletizing apparatus and a method of production of oxidized iron containing agglomerates, wherein energy consumption used for the production can be decreased relative the energy consumption of prior art straight-grate pelletizing apparatuses.

[0022] There is an object to provide a straight-grate pelletizing apparatus and a method of production of oxidized iron containing agglomerates, wherein higher quality of the produced oxidized iron containing agglomerates can be reached relative prior art straight-grate pelletizing apparatuses.

[0023] There is an object to provide a straight-grate pelletizing apparatus and a method of production of oxidized iron containing agglomerates, wherein lower production costs for the production of oxidized iron containing agglomerates can be reached relative production costs for the production of oxidized iron containing agglomerates by means of prior art straight-grate pelletizing apparatuses.

[0024] There is an object to provide a straight-grate pelletizing apparatus and a method of production of oxidized iron containing agglomerates, wherein efficient control of heat energy content fed from the cooling arrangement to the induration arrangement. There is an object to reduce fossil carbon emissions by decreasing or eliminating the use of coal or oil to heat the metal ore material by means of the induration arrangement.

[0025] There is an object to develop prior art straight-grate pelletizing apparatuses and prior art methods of production of oxidized iron containing agglomerates.

[0026] This or at least one of said objects has been achieved by a straight-grate pelletizing apparatus configured for production of oxidized iron containing agglomerates according to claim 1 .

[0027] The feeding device may be positioned upstream and / or downstream the cooling arrangement.

[0028] The gas inlet device may comprise a plurality of oxidation gas muzzles arranged in the agglomerate discharge section and / or in the agglomerate charge section of the induration-cooler transition zone.

[0029] The gas inlet device may comprise a plurality of oxidation gas muzzles arranged in the agglomerate discharge section and / or in the agglomerate charge section of the induration-cooler transition zone in order to supply the oxygen containing gas into the induration-cooler transition zone for completing the oxidization of magnetite.

[0030] The oxygen containing gas may comprise 100% oxygen or less.

[0031] In such a way, final and / or complete oxidization of magnetite of the iron oxide containing agglomerates to hematite is achieved by means of oxygen of the oxygen containing gas targeting the iron oxide containing agglomerates and / or the magnetite of the iron oxide containing agglomerates subject to oxidization in the agglomerate discharge section and / or the agglomerate charge section.

[0032] The induration-cooler transition zone may comprise at least one gas inlet device coupled to the oxygen supply and adapted for injecting oxygen containing gas into the induration-cooler transition zone for targeting the magnetite of the iron oxide containing agglomerates subject to oxidization.

[0033] The gas inlet device may be arranged within the agglomerate charge section and is adapted for injecting oxygen containing gas into the flow of the gaseous fluid in said updraft mode passing through the travelling grate member for targeting the magnetite of the iron oxide containing agglomerates subject to oxidization.

[0034] The gas inlet device may be arranged within the agglomerate charge section and positioned below the travelling grate member.

[0035] The gas inlet device may be arranged within the agglomerate discharge section and is adapted for injecting oxygen containing gas into the flow of the gaseous fluid in said downdraft mode passing through the travelling grate member for targeting the magnetite of the iron oxide containing agglomerates subject to oxidization.

[0036] In such a way, complete oxidization of magnetite to hematite is achieved by means of the oxygen of the oxygen containing gas targeting the iron oxide containing agglomerates and / or the magnetite subject for oxidization.

[0037] The gas inlet device may comprise a plurality of oxidation gas muzzles arranged in the agglomerate discharge section.

[0038] In such a way, final oxidization of magnetite to hematite is provided by oxygen containing gas targeting the magnetite of the iron oxide containing agglomerates subject for oxidization in the induration-cooler transition zone.

[0039] The oxygen containing gas may be in a pre-heated state when passing through the travelling grate member in said downdraft mode and / or said updraft mode for adding heat to the magnetite of the iron oxide containing agglomerates subject to oxidization.

[0040] The gaseous fluid injected with the oxygen containing gas may be pre-heated when targeting the magnetite of the iron oxide containing agglomerates subject to oxidization in said downdraft mode and / or said updraft mode.

[0041] The gas inlet device may be arranged within the agglomerate charge section of the cooling arrangement and may be adapted for injecting oxygen containing gas into the flow of the gaseous fluid for following said flow in said updraft mode through the travelling grate member and targeting the magnetite of the iron oxide containing agglomerates subject to oxidization in said updraft mode.

[0042] The gas inlet device may be arranged within the agglomerate charge section of the cooling arrangement and may be coupled to an oxygen supply via a mechanical gas mixer, which is configured to mix oxygen fed from the oxygen supply with the gaseous fluid.

[0043] The gaseous fluid may be fully formed by oxygen containing gas.

[0044] The gaseous fluid may be partly formed by oxygen containing gas, which gaseous fluid may be provided by mixing oxygen containing gas with air.

[0045] The pre-heated oxygen containing gas may follow the flow of the gaseous fluid in said updraft mode and / or in said downdraft mode for targeting the magnetite of the iron oxide containing agglomerates subject to oxidization.

[0046] The pre-heated oxygen containing gas may be fed in a counterflow stream relative the motion of the iron oxide containing agglomerates moved by the travelling grate member, in the induration-cooler transition zone.

[0047] The induration-cooler transition zone may comprise at least one gas inlet device coupled to an oxygen supply and adapted for injecting an oxygen containing gas following the flow of the gaseous fluid.

[0048] The straight-grate pelletizing apparatus may comprise an updraft gaseous fluid passage channel of the agglomerate charge section and a downdraft gaseous fluid passage channel of the agglomerate discharge section; wherein the channels are configured to guide the gaseous fluid between the updraft gaseous fluid passage channel and the downdraft gaseous fluid passage channel by passing the gaseous fluid through the travelling grate member for targeting the magnetite of the iron oxide containing agglomerates subject for oxidization in the induration-cooler transition zone.

[0049] The sealing arrangement may be arranged between the updraft gaseous fluid passage channel and the downdraft gaseous fluid passage channel for preventing the gaseous fluid to pass in-between a gap between a first carrier / a second carrier of the travelling grate member and the updraft / downdraft gaseous fluid passage channels.

[0050] The sealing arrangement may be configured to prevent the gaseous fluid to be drawn instantaneously from the updraft gaseous fluid passage channel to the downdraft gaseous fluid passage channel and / or to prevent the gaseous fluid (e.g. injected with oxygen containing gas) to pass through said gap. The sealing arrangement may be configured to cover the gap between the first carrier / the second carrier and the downdraft gaseous fluid passage channel.

[0051] This may be provided for sealing the gap between the first carrier / the second carrier and the downdraft gaseous fluid passage channel.

[0052] In such way is achieved optimized flow of the gaseous fluid and / or of the gaseous fluid injected with oxygen containing gas and / or optimized content of oxygen containing gas following the flow of the gaseous fluid through the travelling grate member, thus preventing fully or to at least to some extent, that any gaseous fluid and / or of the gaseous fluid injected with oxygen containing gas would be drawn directly from the updraft gaseous fluid passage channel to the downdraft gaseous fluid passage channel.

[0053] A sealing plate of the sealing arrangement may be hingedly arranged to the upper intersection point about an axis extending transverse the motion direction of the travelling grate member and may be arranged between the updraft gaseous fluid passage channel of the agglomerate charge section and a downdraft gaseous fluid passage channel.

[0054] The upper intersection point may be arranged below the position of travelling grate members passing and may be arranged between the updraft gaseous fluid passage channel and the downdraft gaseous fluid passage channel. A first end portion of the sealing plate may be urged toward the underside of each travelling grate member passing the upper intersection point and thereby preventing that any gaseous fluid and / or of the gaseous fluid injected with oxygen containing gas would move or would been drawn through said gap.

[0055] A counter weight may be arranged to a second end portion of the sealing plate SP, which outermost portion may be located opposite the first end portion. The sealing plate may be urged into sliding and sealing engagement with a bottom section of each carrier passing the upper intersection point by means of counter weight for preventing that any gaseous fluid and / or of the gaseous fluid injected with oxygen containing gas is drawn through said gap. The axis may be positioned between the second end portion and the first end portion. The travelling grate member may comprise a plurality of carriers coupled to each other via coupling members and which may be adapted to carry the iron oxide containing agglomerates subject to oxidization, which iron oxide containing agglomerates comprises the magnetite subject to oxidization.

[0056] The travelling grate member may comprise a conveyor belt configured for carrying and moving the iron oxide containing agglomerates subject to oxidization, which iron oxide containing agglomerates comprises the magnetite subject to oxidization, and moving the oxidized iron containing agglomerates.

[0057] The iron oxide containing agglomerates subject to oxidization may be applied to the travelling grate member (e.g. to the carriers, to the conveyor belt etc.) Such application may be provided by means of iron oxide containing agglomerates charging device configured to apply the iron oxide containing agglomerates to the travelling grate member.

[0058] The iron oxide containing agglomerates may be positioned on the travelling grate member in such way that the iron oxide containing agglomerates forms a pellet bed comprising an upper layer, an intermediate layer and a lower layer.

[0059] The induration arrangement may be configured to oxidize iron oxide containing agglomerates into said oxidized iron containing agglomerates by successively oxidize the iron oxide containing agglomerates through the pellet bed starting from the upper layer toward the intermediate layer and subsequently successively oxidize the iron oxide containing agglomerates further toward the lower layer, and subsequently oxidize the iron oxide containing agglomerates in the lower layer.

[0060] The carriers are coupled to each other and configured to carry the iron oxide containing agglomerates comprising magnetite.

[0061] The induration arrangement may be configured to oxidize the magnetite of the iron oxide containing agglomerates into hematite by successively oxidize the magnetite through the pellet bed starting from the upper layer toward the intermediate layer and subsequently successively oxidize the magnetite further toward the lower layer, and subsequently oxidize the magnetite in the lower layer into hematite.

[0062] The agglomerate charge section may be configured such that the gaseous fluid, injected with oxygen containing gas and fed in the updraft mode, firstly meets the lower layer of the pellet bed to completely oxidize the magnetite in the lower layer into hematite.

[0063] The agglomerate discharge section may be configured such that the gaseous fluid, injected with oxygen containing gas and fed in the downdraft mode, cools the pellet bed and further targets the magnetite in the lower layer for oxidisation of the magnetite into hematite.

[0064] The gaseous fluid introduced into the induration-cooler transition zone may be injected with oxygen containing gas for enhancing the oxygen content of the gaseous fluid in the induration-cooler transition zone, wherein the gaseous fluid injected with oxygen containing gas may be fed through the pellet bed in the updraft mode and the downdraft mode for providing complete oxidization of the magnetite into hematite.

[0065] In such way, the quality of the oxidized iron containing agglomerates is enhanced.

[0066] In such way, the production rate can be enhanced and optimized.

[0067] In such way is achieved that eventual magnetite of the iron oxide containing agglomerates of the pellet bed that is not fully oxidized will be completely oxidized and the oxidized iron containing agglomerates being cooled down by the cooling arrangement.

[0068] The straight-grate pelletizing apparatus may comprise a drying zone for drying upgraded iron oxide containing agglomerates charged into the straight-grate pelletizing apparatus.

[0069] The control circuitry may be adapted to control the gas inlet device for controlling injection of oxygen containing gas into and / or following the gaseous fluid further targeting the iron oxide containing agglomerates for ensuring that eventually not completely oxidized magnetite is oxidized into hematite.

[0070] This or at least one of said objects has been achieved by a method of production of oxidized iron containing agglomerates according to claim 7.

[0071] The step of injecting the oxygen containing gas into the flow of the gaseous fluid in said updraft mode may be performed prior to the gaseous fluid is fed through the travelling grate member. The step of injecting the oxygen containing gas into the flow of the gaseous fluid in said downdraft mode may be performed subsequently the gaseous fluid has been fed through the travelling grate member.

[0072] The step of feeding the gaseous fluid from the gaseous fluid supply unit through the travelling grate member in updraft mode may comprise sealing a gap between the first carrier and the downdraft gaseous fluid passage channel.

[0073] In such way is achieved that any gaseous fluid and / or of the gaseous fluid injected with oxygen is drawn between the first carrier and the updraft and / or downdraft gaseous fluid passage channel.

[0074] The carriers may be coupled to each other and may be configured to carry the iron oxide containing agglomerates comprising magnetite subject to oxidization.

[0075] In such way is achieved that the oxidization rate of the magnetite material of the iron oxide containing agglomerates that passes the induration-cooler transition zone is enhanced.

[0076] This or at least one of said objects has been achieved by a data program according to claim 11 .

[0077] The wording “iron oxide containing agglomerates” may be defined as an iron material comprising hematite material and / or magnetite material and / or wustite material and / or other materials and / or compositions and / or minerals.

[0078] The wording “oxidized iron containing agglomerates” may also be defined as an oxidized iron containing agglomerates comprising an inorganic compound, such as hematite with the formula Fe2O3, wherein the straight-grate pelletizing apparatus is configured for production of oxidized iron containing agglomerates comprising hematite.

[0079] The wording “oxidized iron containing agglomerates” may be defined as an iron material that comprises hematite. The hematite material is defined to be completely oxidized iron containing material of the oxidized iron containing agglomerates and may be defined as an oxidized iron containing material that cannot receive further oxygen atoms.

[0080] The wording “iron” may define an iron material comprising iron oxides (such as magnetite) and / or other minerals and / or gangue or other impurities.

[0081] The induration temperature and time required for induration depend on the mineralogy of the iron oxide containing agglomerates, as well as binder type and amount of the agglomerates.

[0082] The straight-grate pelletizing apparatus may rely on carrying the agglomerates through a number of induration zones (thermal zones) by means of the agglomerates transportation device by moving a perforated grate.

[0083] The term “induration” may be replaced by the word “heat hardening and / or heat treatment”.

[0084] The induration zone configured to indurate the iron oxide containing agglomerates may comprise a section of the cooling zone of the cooler device configured to cool down the oxidized agglomerates by means of the gaseous fluid, wherein further heat treatment of the iron oxide containing agglomerates may proceed in said section during initial cooling. The cooling arrangement configured to cool down the oxidized iron containing material may be regarded to belong to the induration arrangement.

[0085] The induration zone of the straight grate iron oxide pelletizing configurations may be defined to comprise heating zones; drying zones; pre-heating zones (preheating zones) and heating zones (firing and after firing zones) and / or cooling zones of the cooler device.

[0086] The wording “agglomerates” may be replaced by the wording “pellets”.

[0087] The straight-grate pelletizing apparatus configured for production of oxidized iron containing agglomerates may comprise an induration arrangement configured to oxidize an iron oxide containing agglomerates comprising magnetite.

[0088] There is thus achieved that the pellet bed or agglomerate bed will have higher thermal energy than that regarding prior art, which in turn promotes an energy efficient production of the oxidized iron containing agglomerates and also improves the quality of the produced oxidized iron containing agglomerates.

[0089] The oxygen containing pre-heated process gas may be set by means of the control circuitry to exhibit a temperature set by means of a heating device and / or flow rate set by the feeding device, for causing the iron oxide containing agglomerates subjected to be oxidized (and / or sintered) to exhibit a desired temperature.

[0090] The oxygen containing gas may be in a pre-heated state and may be heated by the heating device controlled by the control circuitry to exhibit a raised temperature of the oxygen containing gas when passing through the bed of iron oxide containing agglomerates comprising magnetite.

[0091] The raised temperature of the oxygen containing gas fed into the gaseous fluid targeting the iron oxide containing agglomerates will thus promote for efficient oxidization.

[0092] The gaseous fluid injected with the oxygen containing gas may be pre-heated when targeting the magnetite of the iron oxide containing agglomerates subject to oxidization in said downdraft mode and / or said updraft mode.

[0093] The gaseous fluid fed through an updraft gaseous fluid passage channel is heated in updraft mode by means of cooling down the oxidized iron containing agglomerates, wherein heat is transferred from the oxidized iron containing agglomerates to the gaseous fluid.

[0094] The oxygen content of the gaseous fluid injected with oxygen may be controlled by the control circuitry to exhibit a (desired) content of oxygen set by means of the control circuitry and / or may be controlled by the control circuitry in controlling the flow rate of the gaseous fluid injected with oxygen.

[0095] The control circuitry may be adapted to cause the iron oxide containing agglomerates subjected to be oxidized (and / or sintered) to exhibit a temperature of; about 700°C - 900°C, preferably about 750°C - 850°C; or about 750°C - 950°C, preferably about 800°C - 900°C; or about 800°C - 1000°C, preferably about 850°C - 950°C; or about 850°C - 1050°C, preferably about 900°C - 1000°C; or about 900°C - 1100°C, preferably about 950°C - 1050°C; or about 950°C - 1150°C, preferably about 1000°C - 1100°C; or about 1000°C - 1200°C, preferably about 1050°C - 1150°C; or about 1050°C - 1250°C, preferably about 1100°C - 1200°C; or about 1100°C - 1300°C, preferably about 1150°C - 1250°C.

[0096] By means of the gaseous fluid injected with oxygen by means of the added oxygen containing gas there is provided higher oxidation rate of the magnetite of the iron oxide containing agglomerates versus prior art configurations.

[0097] The oxygen containing gas may comprise about 80 to 100% oxygen.

[0098] The oxygen containing gas may comprise about 60 to 80% oxygen.

[0099] The oxygen containing gas may comprise about 40 to 60% oxygen.

[0100] The gaseous fluid injected with oxygen may be controlled to comprise a desired content of oxygen by means of the control circuitry coupled to the at least one gas inlet device for controlling and / or regulating the amount of oxygen fed into the gaseous fluid, wherein the gaseous fluid injected with oxygen may comprise; about 21-40vol% oxygen, preferably about 23-37vol% oxygen; or about 30-50vol% oxygen, preferably about 33-47vol% oxygen; or about 40-60vol% oxygen, preferably about 43-57vol% oxygen; or about 50-70vol% oxygen, preferably about 53-67vol% oxygen; or about 60-80vol% oxygen, preferably about 63-77vol% oxygen; or about 70-90vol% oxygen, preferably about 73-87vol% oxygen; or about 80-100vol% oxygen, preferably about 83-97vol% oxygen. By means of the gaseous fluid injected with oxygen, the agglomerate bed will be completely oxidated.

[0101] It is thus achieved that the agglomerate bed will be completely oxidized, wherein the high oxygen content of the gaseous fluid in the induration-cooler transition zone provides an energy efficient oxidization of the magnetite material.

[0102] In such way is achieved that the production rate can be increased due to a more energy effective process at the same time as the quality of the oxidized iron containing agglomerates is enhanced.

[0103] In such way there is achieved that the oxidation rate of the magnetite material of the iron oxide containing agglomerates for production of the oxidized iron containing agglomerates is increased relative prior art straight-grate pelletizing apparatuses.

[0104] In such way there is achieved that the production rate is increased relative prior art straight-grate pelletizing apparatuses.

[0105] In such way the gaseous fluid injected with oxygen can be used as a cooling medium for cooling the oxidized iron containing agglomerates.

[0106] The straight-grate pelletizing apparatus may comprise a gaseous fluid transfer line arrangement coupled to a wind box of an updraft gaseous fluid passage channel.

[0107] A first and a second gas inlet device may be positioned at sufficient distance from the wind box and upstream seen in the flow direction of the gaseous fluid for allowing installation of a static mixer in the gaseous fluid transfer line arrangement.

[0108] The static mixer may comprise at least one guiding gas element angled relative the flow direction of the incoming flow of gaseous fluid comprising the oxygen containing gas.

[0109] In such way is achieved that oxygen transferred (e.g. by means of a feeding device, such as a gas pump) from the agglomerate charge section of the cooling arrangement to the agglomerate discharge section of the induration arrangement reaches the bottom layer of the iron containing material bed in the agglomerate discharge section.

[0110] This promotes effective oxidizing of the bottom layer of the iron containing material bed moved in the agglomerate discharge section of the induration arrangement. The moving iron containing material bed in the machine upstream of the agglomerate discharge section of the induration arrangement is heated and oxidised from above (from the top layer of the bed) toward the bottom layer of the iron containing material bed. That is, in the agglomerate discharge section of the induration arrangement, the bottom layer of the iron oxide containing agglomerate bed has reached high temperature suitable for further oxidization and the oxygen led to the agglomerate discharge section of the induration arrangement from the agglomerate charge section of the cooling arrangement ensures that effective oxidization of the bottom layer of the iron containing material bed is achieved.

[0111] The present disclosure or disclosures may not be restricted to the examples described above, but many possibilities to modifications, or combinations of the described examples thereof should be apparent to a person with ordinary skill in the art without departing from the basic idea as defined in the appended claims.

[0112] BRIEF DESCRIPTION OF THE DRAWINGS

[0113] The present invention will now be described by way of examples with references to the accompanying schematic drawings, of which:

[0114] Fig. 1 illustrates a straight-grate pelletizing apparatus according to a first example;

[0115] Fig. 2 illustrates a straight-grate pelletizing apparatus according to a second example;

[0116] Fig. 3 illustrates a straight-grate pelletizing apparatus according to a third example;

[0117] Fig. 4 illustrates a straight-grate pelletizing apparatus according to a fourth example;

[0118] Fig. 5 illustrates a portion of a straight-grate pelletizing apparatus according to a fifth example;

[0119] Fig. 6 illustrates a portion of a straight-grate pelletizing apparatus according to a sixth example; Fig. 7 illustrates a portion of a straight-grate pelletizing apparatus in a side view according to a seventh example;

[0120] Fig. 8 illustrates a flowchart showing an exemplary method of production of oxidized iron containing agglomerates by means of a straight-grate pelletizing apparatus;

[0121] Fig. 9 illustrates a flowchart showing an exemplary method of production of oxidized iron containing agglomerates by means of a straight-grate pelletizing apparatus; Fig. 10 illustrates a control circuitry of an iron oxide pelletizing configuration according to a further example;

[0122] Fig. 11 a shows an example of positioning the gas inlet device of the straight-grate pelletizing apparatus according to a further example; and

[0123] Fig. 11 b shows a further example of positioning the gas inlet device of the straightgrate pelletizing apparatus.

[0124] DETAILED DESCRIPTION

[0125] Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings, wherein for the sake of clarity and understanding of the invention some details of no importance may be deleted from the drawings. Same reference number may correspond to similar member / device / flow etc. in different drawings.

[0126] Fig. 1 illustrates a straight-grate pelletizing apparatus 1 according to a first example.

[0127] The straight-grate pelletizing apparatus 1 configured for production of oxidized iron containing agglomerates 4. The straight-grate pelletizing apparatus 1 comprises an induration arrangement 3 configured to oxidize an iron containing material 2 passing through the induration arrangement 3. The induration arrangement 3 comprises a pre-heating zone PH, a firing zone F, an after-firing zone divided into a first afterfiring zone AF1 and a second after-firing zone AF2. The iron containing material 2 fed through the induration arrangement comprises magnetite, which magnetite oxidizes into hematite of the oxidized iron containing agglomerates 4.

[0128] A cooling arrangement 5 is configured to cool down the oxidized (indurated) iron containing material 4.

[0129] The straight-grate pelletizing apparatus 1 further comprises an induration-cooler transition zone TZ having an agglomerate discharge section 6 of the induration arrangement 3 and having an agglomerate charge section 8 of the cooling arrangement 5.

[0130] A travelling grate member 7 is configured to carry the iron containing material 2 subject to be oxidized and / or the oxidized iron containing agglomerates through the induration-cooler transition zone TZ.

[0131] Alternatively, the travelling grate member 7 comprises a set of carriers (not shown) configured to carry the iron containing material 2 and the subsequently indurated and oxidized iron containing agglomerates 4.

[0132] The straight-grate pelletizing apparatus 1 further comprises a gaseous fluid supply unit 9 coupled to a feeding device FD, such as a gas pump. The feeding device FD is configured to feed a gaseous fluid 11 through the travelling grate member 7 in updraft mode at the agglomerate charge section 8 for cooling down the oxidized iron containing agglomerates 4 discharged from the second after-firing zone AF2.

[0133] The gaseous fluid 11 is heated by the warm / hot oxidized (indurated) iron containing material 4 in said updraft mode. Thereafter, the gaseous fluid 11 is fed through the carriers for cooling of - and providing complementary oxygen to - the oxidized (indurated) iron containing material 4, for ensuring that eventually not completely oxidized magnetite of the oxidized (indurated) iron containing material 4 that has passed and subjected to induration by the induration arrangement 3 fully is oxidized into hematite.

[0134] The gaseous fluid 11 is further fed in a direction opposite the travelling direction of the travelling grate member 7 and further in downdraft mode at the agglomerate discharge section 6 by means of said feeding device FD. A control circuitry (not shown) is adapted to control the operation of the straight-grate pelletizing apparatus 1 .

[0135] The induration-cooler transition zone TZ may comprise at least one gas inlet device (not shown) coupled to an oxygen supply (not shown), which gas inlet device (such as a nozzle) is adapted for injecting an oxygen into the gaseous fluid 11 for oxidizing the magnetite of the iron containing material 2 subject to oxidization for providing completely oxidized magnetite.

[0136] The gas inlet device may be arranged within the agglomerate charge section 8 and may be adapted for injecting the oxygen containing gas into the flow of the gaseous fluid 11 in said updraft mode passing through the carriers of the travelling grate member 7 passing the agglomerate charge section 8 for targeting eventually not oxidized magnetite.

[0137] The gas inlet device may be arranged within the agglomerate discharge section 6 and may be adapted for injecting the oxygen containing gas into the flow of the gaseous fluid 11 in said downdraft mode passing through the carriers in the agglomerate discharge section 6 for targeting the magnetite of the iron containing material subject to oxidization.

[0138] The straight-grate pelletizing apparatus 1 may comprise a drying zone DZ for drying upgraded iron containing material charged into the straight-grate pelletizing apparatus 1 .

[0139] Fig. 2 illustrates a straight-grate pelletizing apparatus 1 according to a second example. The straight-grate pelletizing apparatus 1 is configured for production of oxidized iron containing agglomerates 4. The straight-grate pelletizing apparatus 1 comprises an induration arrangement 3 configured to oxidize an iron containing material 2 passing through the induration arrangement 3. The induration arrangement 3 an after-firing zone divided into a first after-firing zone AF1 and a second after-firing zone AF2. A cooling arrangement 5 is configured to cool down the oxidized (indurated) iron containing material 4. The straight-grate pelletizing apparatus 1 further comprises an induration-cooler transition zone TZ having an agglomerate discharge section 6 and an agglomerate charge section 8. A travelling grate member 7 is configured to carry the iron containing material 2. A gaseous fluid supply unit 9 coupled to a feeding device FD. A gaseous fluid 11 is fed through the travelling grate member 7 in updraft mode at the agglomerate charge section 8 for cooling down the oxidized iron containing agglomerates 4 discharged from the second after-firing zone AF2. The gaseous fluid 11 is heated by the warm / hot oxidized (indurated) iron containing material 4 in said updraft mode. Thereafter, the gaseous fluid 11 is fed through the carriers for cooling of - and providing complementary oxygen to - the oxidized (indurated) iron containing material 4 for reaching that eventually not completely oxidized magnetite of the oxidized (indurated) iron containing material 4 that has passed and subjected to induration by the induration arrangement 3 fully is oxidized into hematite.

[0140] The gaseous fluid 11 is further fed in downdraft mode at the agglomerate discharge section 6 by means of said feeding device FD.

[0141] The agglomerate discharge section 6 may comprise at least one gas inlet nozzle 13’ coupled to an oxygen supply 16. A control circuitry (not shown) is adapted to control the gas inlet nozzle 13’ for controlled injection of oxygen containing gas 15 into and / or following the gaseous fluid 11 further targeting the iron containing material 2 for ensuring that eventually not completely oxidized magnetite is transferred into hematite.

[0142] Fig. 3 illustrates a straight-grate pelletizing apparatus 1 according to a third example. The straight-grate pelletizing apparatus 1 comprises a travelling grate member 7 comprises a set of carriers 20 configured to carry iron containing material to be indurated and further carrying the oxidized iron containing agglomerates 4 to a turnabout wheel to be discharged from a cooling arrangement 5 configured to cool down the oxidized iron containing agglomerates 4. An oxygen content sensing sensor arrangement SA is arranged to a downdraft gaseous fluid passage channel 18 of a downdraft zone. The oxygen sensing sensor arrangement SA is electrically coupled to a control circuitry 50. The control circuitry 50 is adapted to control an gas inlet nozzle 13’ and / or an oxygen supply 16 for controlled injection of oxygen containing gas 15 into and / or following the gaseous fluid 11 further targeting the iron containing material subject to induration for ensuring that eventually not completely oxidized magnetite is oxidized into hematite. The gaseous fluid 11 fed through an updraft gaseous fluid passage channel 19 is heated in updraft mode by means of cooling down the oxidized iron containing agglomerates 4, wherein heat is transferred from the oxidized iron containing agglomerates 4 to the gaseous fluid 11 .

[0143] Fig. 4 illustrates a straight-grate pelletizing apparatus 1 according to a fourth example. The straight-grate pelletizing apparatus 1 is configured for production of oxidized iron containing agglomerates. The straight-grate pelletizing apparatus 1 comprises an induration arrangement 3 configured to oxidize an iron containing material passing through the induration arrangement 3. The induration arrangement 3 comprises an after-firing zone divided into a first after-firing zone AF1 and a second after-firing zone AF2. A cooling arrangement 5 is configured to cool down the oxidized (indurated) iron containing material.

[0144] The straight-grate pelletizing apparatus 1 further comprises an induration-cooler transition zone TZ having an agglomerate discharge section 6 and an agglomerate charge section 8.

[0145] A travelling grate member 7 is configured to carry the iron containing material. A gaseous fluid supply unit 9 coupled to a feeding device FD. A gaseous fluid 11 is fed through the travelling grate member 7 in updraft mode at the agglomerate charge section 8 for cooling down the oxidized iron containing agglomerates 4 discharged from the second after-firing zone AF2.

[0146] The gaseous fluid 11 is heated by the warm / hot oxidized (indurated) iron containing material 4 in said updraft mode. Thereafter, the gaseous fluid 11 is fed through the carriers for cooling of - and providing complementary oxygen 15 to - the oxidized (indurated) iron containing material 4, for reaching that eventually not completely oxidized magnetite of the oxidized (indurated) iron containing material 4 that has passed and subjected to induration by the induration arrangement 3 fully is oxidized into hematite when leaving the agglomerate charge section 8.

[0147] The gaseous fluid 11 is further fed in downdraft mode at the agglomerate discharge section 6 by means of said feeding device FD.

[0148] The agglomerate charge section 8 may comprise at least one gas inlet nozzle 13”, 13”’ coupled to an oxygen supply 16. A control circuitry (not shown) may be adapted to control the gas inlet nozzle 13”, 13”’ for controlled injection of oxygen containing gas into and / or following the gaseous fluid 11 further targeting the iron containing material / oxidized (indurated) iron containing material for ensuring that eventually not completely oxidized magnetite is transferred into hematite.

[0149] Fig. 5 illustrates a portion of a straight-grate pelletizing apparatus according to a fifth example. This example shows updraft gaseous fluid passage channels 17, 19 of the agglomerate charge section 8 and a downdraft gaseous fluid passage channel 18 of the agglomerate discharge section 6.

[0150] The channels 17, 18, 19 may be configured to guide a gaseous fluid 11 between the updraft gaseous fluid passage channel 17, 19 and the downdraft gaseous fluid passage channel 18 by passing the gaseous fluid 11 through the travelling grate member 7 for reaching the iron containing material and targeting not yet oxidized magnetite of the iron containing material subjected for oxidization in the indurationcooler transition zone.

[0151] A sealing arrangement (e.g. a rocker plate) 21 is arranged between the updraft gaseous fluid passage channel 19 and the downdraft gaseous fluid passage channel 18 for preventing the gaseous fluid 11 to pass in-between a gap between the carrier and the downdraft gaseous fluid passage channel. The carriers are coupled to each other and are configured to carry the iron containing material subject to oxidization and subsequenty carry the oxidized (indurated) iron containing material 4.

[0152] Fig. 6 illustrates a portion of a straight-grate pelletizing apparatus in a view from above according to a sixth example. There is shown a sealing arrangement 21 comprising six tiltable sealing plates SP made of fire proof material. The sealing plates SP are tiltable about a common axis X and are positioned between the updraft gaseous fluid passage channel 19 and the downdraft gaseous fluid passage channel 18 for preventing the gaseous fluid to pass in-between a gap between undersides of the carriers and the downdraft gaseous fluid passage channel. The carriers are configured to carry the iron containing material subject to oxidization and carry the oxidized (indurated) iron containing material.

[0153] The sealing arrangement 21 thus may be configured to cover the gap between the first carrier and the downdraft gaseous fluid passage channel when the first carrier moves over an upper intersection point IP intersecting the updraft gaseous fluid passage channel 19 and the downdraft gaseous fluid passage channel 18. In such way is achieved optimized flow of the gaseous fluid and / or of the gaseous fluid injected with oxygen containing gas and / or optimized content of oxygen containing gas following the flow of the gaseous fluid through the travelling grate member, thus preventing fully or to at least to some extent, that any gaseous fluid and / or of the gaseous fluid injected with oxygen containing gas is drawn directly from the updraft gaseous fluid passage channel to the downdraft gaseous fluid passage channel.

[0154] A set of gas inlet nozzle 13” is arranged to the updraft gaseous fluid passage channel 19 and control by a control circuitry (not shown) for controlled injection of oxygen containing gas into and / or following the gaseous fluid further targeting the iron containing material / oxidized (indurated) iron containing material for ensuring that eventually not completely oxidized magnetite is transferred into hematite.

[0155] Fig. 7 illustrates a portion of a straight-grate pelletizing apparatus in a side view according to a seventh example. According to this example there are gas inlet nozzles 13” arranged on both sides of the updraft gaseous fluid passage channel 19. The gas inlet nozzles 13” thus being arranged within an agglomerate charge section of a cooling arrangement 5 and may be adapted for injecting oxygen containing gas into the flow of gaseous fluid and / or following said flow of gaseous fluid in an updraft mode through the travelling grate member and targeting the magnetite of the iron containing material subject to oxidization in said updraft mode. The gas inlet nozzles 13” are coupled to an oxygen supply 16.

[0156] A control circuitry (not shown) may be adapted to control the gas inlet nozzle 13”, 13”’ for controlled injection of oxygen containing gas into and / or following the gaseous fluid 11 further targeting the iron containing material / oxidized (indurated) iron containing material for ensuring that eventually not completely oxidized magnetite is transferred into hematite.

[0157] A sealing arrangement 21 is positioned between the updraft gaseous fluid passage channel 19 and the downdraft gaseous fluid passage channel 18 for preventing the gaseous fluid to pass in-between said gap.

[0158] Fig. 8 illustrates a flowchart showing an exemplary method of production of oxidized iron containing agglomerates by means of a straight-grate pelletizing apparatus which comprises; an induration arrangement configured to oxidize an iron containing material comprising magnetite into said oxidized iron containing agglomerates; a cooling arrangement configured to cool down the oxidized iron containing agglomerates; an induration-cooler transition zone comprising an agglomerate discharge section of the induration arrangement and comprising an agglomerate charge section of the cooling arrangement; a travelling grate member configured to carry the iron containing material subject to be oxidized and / or the oxidized iron containing agglomerates through the induration-cooler transition zone; a gaseous fluid supply unit coupled to a feeding device of the straight-grate pelletizing apparatus configured to feed a gaseous fluid through the travelling grate member in updraft mode at the agglomerate charge section for cooling down the oxidized iron containing agglomerates, wherein the gaseous fluid heated by the oxidized iron containing agglomerates in said updraft mode subsequently is fed through the travelling grate member in downdraft mode at the agglomerate discharge section by means of said feeding device; a control circuitry 50 adapted to control the operation of the straight-grate pelletizing apparatus; and the induration-cooler transition zone comprises at least one gas inlet device coupled to an oxygen supply and adapted for injecting an oxygen containing gas into the gaseous fluid for targeting the iron containing material subject to oxidization. The method in Fig. 8 starts at step 101. Step 102 performs the method. Step 103 stops the method.

[0159] Step 102 may comprise the steps of charging the iron containing material into the induration arrangement, moving the iron containing material via the agglomerate discharge section of the induration arrangement to the agglomerate charge section of the cooling arrangement, feeding the gaseous fluid from the gaseous fluid supply unit through the travelling grate member in updraft mode and in downdraft mode, injecting the oxygen containing gas into the gaseous fluid by means of the at least one gas inlet device providing that the gaseous fluid injected with oxygen containing gas targets the iron containing material for enhancing the oxidization rate of magnetite material of the iron containing material.

[0160] Fig. 9 illustrates a flowchart showing a further exemplary method of production of oxidized iron containing pellets by means of an exemplary straight-grate pelletizing apparatus. The method starts at step 111. Step 112 may comprise charging the iron containing material into the induration arrangement. Step 113 may comprise moving the iron containing material via the agglomerate discharge section of the induration arrangement to the agglomerate charge section of the cooling arrangement. Step

[0161] 114 may comprise feeding the gaseous fluid from the gaseous fluid supply unit through the travelling grate member in updraft mode and in downdraft mode. Step

[0162] 115 may comprise injecting the oxygen containing gas into the gaseous fluid by means of the at least one gas inlet device providing that the gaseous fluid injected with oxygen containing gas targets the iron containing material for enhancing the oxidization rate of magnetite material of the iron containing material. Step 116 may involve that the step of injecting the oxygen containing gas into the flow of the gaseous fluid in said updraft mode is performed prior to the gaseous fluid is fed through the travelling grate member. Step 117 may involve that the step of injecting the oxygen containing gas into the flow of the gaseous fluid in said downdraft mode is performed subsequently the gaseous fluid has been fed through the travelling grate member. Step 118 may involve the step of feeding the gaseous fluid from the gaseous fluid supply unit through the travelling grate member in updraft mode comprises sealing a gap between a first carrier and the downdraft gaseous fluid passage channel. Step 119 may stop the method.

[0163] Fig. 10 illustrates a control circuitry 50 of a straight-grate pelletizing apparatus 1 according to a further example. The control circuitry 50 comprises a computer (not shown) and is configured to control any exemplary method herein.

[0164] The control circuitry 50 may comprise a non-volatile memory NVM 920, which is a computer memory that can retain stored information even when the control circuitry 50 or the computer is not powered. The control circuitry 50 further comprises a processing unit 910 and a read / write memory 950.

[0165] The NVM 920 comprises a first memory unit 930. A computer program (which can be of any type suitable for any operational database) is stored in the first memory unit 930 to be used for operating the functionality and processing of the control circuitry 50.

[0166] Furthermore, the control circuitry 50 comprises a bus controller (not shown), a serial communication port (not shown) providing a physical interface, through which information transfers separately in two directions.

[0167] The control circuitry 50 may comprise any suitable type of I / O module (not shown) providing input / output signal transfer, and / or an A / D converter (not shown) for converting varying signals into binary code suitable to be processed by the computer of the control circuitry 50.

[0168] The signals may be sent from a temperature sensor member for detecting temperatures of the iron containing material subject to induration and the temperature of the oxidized iron containing agglomerates ready for cooling and / or for detecting temperatures of injected oxygen containing gas and / or the temperature of the gaseous fluid targeting the iron containing material subject to oxidization.

[0169] The control circuitry 50 may be adapted to convert varying signals fed from an oxygen content detecting sensor member configured to detect the oxygen content of the injected oxygen containing gas and / or the oxygen content of the gaseous fluid.

[0170] The control circuitry 50 may be electrically coupled to said temperature sensor members and adapted to control the at least one gas inlet device for regulating the content the oxygen in the gaseous fluid and / or following the gaseous fluid.

[0171] The control circuitry 50 further may comprise an input / output unit (not shown) for adaption to time and date. The control circuitry 50 also may comprise an event counter (not shown) for counting the number of event multiples that occurs during the induration (oxidization) of the iron containing material and adaption of the oxidization for reaching efficient oxidization of magnetite to hematite.

[0172] Furthermore, the control circuitry 50 may include interrupt units (not shown) for providing a multi-tasking performance and real time computing. The NVM 920 also includes a second memory unit 940 for external controlled operation.

[0173] A data medium adapted for storing a data program P may comprise driver routines adapted for commanding the operating of the straight-grate pelletizing apparatus 1 .

[0174] The data program P is adapted for operating the control circuitry 50 in performing any exemplary method described herein. The data program P comprises routines for executing commands to the straight-grate pelletizing apparatus 1 for achieving any of the exemplary methods herein disclosed.

[0175] The data program P comprises a program code, which is readable on the computer, for causing the computer to control the straight-grate pelletizing apparatus 1 to perform an exemplary method herein described. The data program P further may be stored in a separate memory 960 and / or in the read / write memory 950. The data program P in this embodiment is stored in executable or compressed data format.

[0176] It is to be understood that when the processing unit 910 is described to execute a specific function that involves that the processing unit 910 executes a certain part of the program stored in the separate memory 960 or a certain part of the program stored in the read / write memory 950.

[0177] The processing unit 910 is associated with a signal (data) port 999 for communication via a first data bus 915, which signal (data) port 999 may be adapted to be electrically coupled to an electronic control circuitry of an operator station (not shown).

[0178] In such way is achieved that an operator via a display of the electronic control circuitry can control and monitor the straight-grate pelletizing apparatus 1 .

[0179] The non-volatile memory NVM 920 is adapted for communication with the processing unit 910 via a second data bus 912. The separate memory 960 is adapted for communication with the processing unit 910 via a third data bus 911 . The read / write memory 950 is adapted to communicate with the processing unit 910 via a fourth data bus 914. The signal (data) port 999 may be connectable to data links of e.g. a network coupled to the control circuitry 50.

[0180] When data is received by the signal port 999, the data will be stored temporary in the second memory unit 940. After that the received data is temporary stored, the processing unit 910 will be ready to execute the program code, in accordance with the exemplary methods.

[0181] Preferably, the signals (received by the signal (data) port 999) comprise information about operational status of the straight-grate pelletizing apparatus 1 .

[0182] The received signals at the signal port 999, such as a serial bus, may be used by the control circuitry 50 for controlling and monitoring the oxidization of the magnetite material.

[0183] The signals received by the signal (data) port 999 can be used for historic data and data regarding operation of the straight-grate pelletizing apparatus 1 . The straight-grate pelletizing apparatus 1 may be configured to be coupled to a data network via the signal port 999 configured for electrical interface explicitly and providing electrical compatibility and data transfer.

[0184] The data may include information about status of the straight-grate pelletizing apparatus 1 comprising the above-mentioned sensor members. Data may also be fed manually to the computer and / or presented by the computer via a suitable communication device, such as a display (not shown) or touch screen.

[0185] Separate sequences of the method may be executed by the computer, wherein the computer runs the data program P being stored in the separate memory 960 or the read / write memory 950. When the computer runs the data program P, the method steps according to any example disclosed herein would be executed by means of the straight-grate pelletizing apparatus 1 .

[0186] The data program P is programmed with a program code adapted for causing an exemplary straight-grate pelletizing apparatus 1 to execute any exemplary method herein disclosed.

[0187] Alternatively, a data program product comprising a program code stored on a data medium may be provided, which data program product is readable on the computer, for commanding the iron oxide pelletizing configuration 1 to perform any of the exemplary method steps herein disclosed, when the data program P is run on the computer.

[0188] Fig. 11a shows a portion of a straight-grate pelletizing apparatus configured for production of oxidized iron containing agglomerates (not shown). The straight-grate pelletizing apparatus comprises an induration arrangement 3 configured to oxidize iron oxide containing agglomerates (not shown) comprising magnetite into said oxidized iron containing agglomerates, wherein the magnetite of the iron oxide containing agglomerates has been oxidized into hematite. A cooling arrangement 5 is configured to cool down the oxidized iron containing agglomerate.

[0189] A travelling grate member 7 is configured to carry the iron oxide containing agglomerates subject to be oxidized and / or the oxidized iron containing agglomerates through an induration-cooler transition zone TZ. A gaseous fluid supply unit (not shown) is configured to feed a gaseous fluid 11 through the travelling grate member 7 in updraft mode for cooling down the oxidized iron containing agglomerates. The gaseous fluid 11 is heated by the oxidized iron containing agglomerates in said updraft mode. Subsequently, the gaseous fluid supply unit provides downdraft mode of the gaseous fluid 11 through the travelling grate member 7 and the iron oxide containing agglomerates in the induration arrangement 3 for providing completed oxidization of the iron oxide containing agglomerates. A control circuitry (not shown) is adapted to control the operation of the straight-grate pelletizing apparatus.

[0190] A first and a second gas inlet device 14’, 14” may be coupled to an oxygen supply 16 and may be adapted for injecting an oxygen containing gas (not shown) into the gaseous fluid 11 for targeting the iron oxide containing agglomerates subject to oxidization.

[0191] The first and the second gas inlet device 14’, 14” may be positioned at sufficient distance from an updraft gaseous fluid passage channel (such as a wind box 19’) for allowing installation of a static mixer SM in a gaseous fluid transfer line arrangement LA coupled to the wind box 19’.

[0192] The static mixer SM may comprise at least one guiding gas element 12 (such as a plate member) angled relative the flow direction of the incoming flow of gaseous fluid 11 comprising the oxygen containing gas 15.

[0193] Preferably, the static mixer SM may comprise at least two plate members which are angled also in relation to each other for providing sufficient mix of the oxygen containing gas 15 with the gaseous fluid.

[0194] The control circuitry is adapted to control the first and the second gas inlet device 14’, 14” for controlled injection of oxygen containing gas into and / or following the gaseous fluid 11 fed through the gaseous fluid transfer line arrangement LA.

[0195] The gaseous fluid 11 comprising (mixed with) the oxygen containing gas is heated by the oxidized iron containing agglomerates in said updraft mode and further drawn into the induration arrangement 3 for providing said downdraft mode of the (heated) gaseous fluid 11 comprising (mixed with) the oxygen containing gas through the travelling grate member 7 and the iron oxide containing agglomerates. A separate gas inlet device 14”’ may be arranged further up-stream in a main channel MC for injecting an oxygen containing gas15 into the flow of gaseous fluid 11 in the main channel MC.

[0196] Fig. 11 b shows a portion of a gaseous fluid transfer line arrangement configured to feed gaseous fluid 11 to a first and second updraft gaseous fluid passage channel comprising a respective first 19’ and second wind box 19”.

[0197] A first and / or a second gas inlet device 14’, 14” each configured to inject an oxygen containing gas into the gaseous fluid 11 may be positioned at sufficient distance from the respective first 19’ and second wind box 19”. A static mixer (not shown) may be positioned between a fluid pump FP and the wind boxes.

[0198] The first gas inlet device 14’ may be positioned downstream the fluid pump FP and / or the second gas inlet device 14” may be positioned upstream the fluid pump FP.

[0199] The present disclosure or disclosures may not be restricted to the examples described above, but many possibilities to modifications, or combinations of the described examples thereof should be apparent to a person with ordinary skill in the art without departing from the basic idea as defined in the appended claims.

Claims

CLAIMS1 . A straight-grate pelletizing apparatus (1 ) configured for production of oxidized iron containing agglomerates (4), which straight-grate pelletizing apparatus (1 ) comprises;-an induration arrangement (3) configured to oxidize iron oxide containing agglomerates (2) comprising magnetite into said oxidized iron containing agglomerates (4) wherein the magnetite of the iron oxide containing agglomerates (2) has oxidized into hematite;-a cooling arrangement (5) configured to cool down the oxidized iron containing agglomerate (4);-an induration-cooler transition zone (TZ) comprising an agglomerate discharge section (6) of the induration arrangement (3) and comprising an agglomerate charge section (8) of the cooling arrangement (5);-a travelling grate member (7) configured to carry the iron oxide containing agglomerates (2) subject to be oxidized and / or the oxidized iron containing agglomerates (4) through the induration-cooler transition zone (TZ);-a gaseous fluid supply unit (9) coupled to a feeding device (FD) of the straight-grate pelletizing apparatus (1 ) configured to feed a gaseous fluid (11 ) through the travelling grate member (7) in updraft mode at the agglomerate charge section (8) for cooling down the oxidized iron containing agglomerates (4), wherein the gaseous fluid (11 ) heated by the oxidized iron containing agglomerates (4) in said updraft mode subsequently is fed through the travelling grate member (7) in downdraft mode at the agglomerate discharge section (6) by means of said feeding device (FD); and-a control circuitry (50) adapted to control the operation of the straight-grate pelletizing apparatus (1 ); characterized in that-the induration-cooler transition zone (TZ) comprises at least one gas inlet device (13’, 13”, 13”’) coupled to an oxygen supply (16) and adapted for injecting an oxygen containing gas (15) into the gaseous fluid (11 ) for targeting the iron oxide containingagglomerates (2) subject to oxidization, wherein the magnetite of the iron oxide containing agglomerates (2) is oxidised into hematite.

2. The straight-grate pelletizing apparatus (1 ) according to claim 1 , wherein-the gas inlet device (13”, 13”’) is arranged within the agglomerate charge section (8) and is adapted for injecting the oxygen containing gas (15) into the flow of the gaseous fluid (11 ) in said updraft mode passing through the travelling grate member (7) for targeting the magnetite of the iron oxide containing agglomerates subject to oxidization.

3. The straight-grate pelletizing apparatus (1 ) according to claim 1 or 2, wherein-the gas inlet device (13’) is arranged within the agglomerate discharge section (6) and is adapted for injecting the oxygen containing gas (15) into the flow of the gaseous fluid (11 ) in said downdraft mode passing through the travelling grate member (7) for targeting the magnetite of the iron oxide containing agglomerates subject to oxidization.

4. The straight-grate pelletizing apparatus (1 ) according to any of claims 1 to 3, wherein the straight-grate pelletizing apparatus (1 ) further comprises;-an updraft gaseous fluid passage channel (17, 19) of the agglomerate charge section (8) and a downdraft gaseous fluid passage channel (18) of the agglomerate discharge section (6); wherein the channels (17, 18, 19) are configured to guide the gaseous fluid (11 ) between the updraft gaseous fluid passage channel (17, 19) and the downdraft gaseous fluid passage channel (18) by passing the gaseous fluid (11) through the travelling grate member (7) for targeting the magnetite of the iron oxide containing agglomerates subject for oxidization in the induration-cooler transition zone.

5. The straight-grate pelletizing apparatus (1 ) according to claim 4, wherein-a sealing arrangement (21 ) is arranged between the updraft gaseous fluid passage channel (19) and the downdraft gaseous fluid passage channel (18) for preventing the gaseous fluid (11 ) to pass in-between a gap between a first carrier (20’) and a downdraft gaseous fluid passage channel, which first carrier (20’) is coupled to a second carrier (20”) and configured to carry the iron oxide containing agglomerates(2) subject to oxidization.

6. The straight-grate pelletizing apparatus (1) according to any of the preceding claims, wherein the straight-grate pelletizing apparatus (1 ) comprises a drying zone for drying upgraded iron oxide containing agglomerates charged into the straightgrate pelletizing apparatus (1 ).

7. A method of production of oxidized iron containing agglomerates (4) by means of a straight-grate pelletizing apparatus (1 ), which comprises; an induration arrangement(3) configured to oxidize iron oxide containing agglomerates (2) comprising magnetite into said oxidized iron containing agglomerates (4); a cooling arrangement (5) configured to cool down the oxidized iron containing agglomerates (4); an indurationcooler transition zone (TZ) comprising an agglomerate discharge section (6) of the induration arrangement (3) and comprising an agglomerate charge section (8) of the cooling arrangement (5); a travelling grate member (7) configured to carry the iron oxide containing agglomerates (2) subject to be oxidized and / or the oxidized iron containing agglomerates (4) through the induration-cooler transition zone (TZ); a gaseous fluid supply unit (9) coupled to a feeding device (FD) of the straight-grate pelletizing apparatus (1 ) configured to feed a gaseous fluid (11 ) through the travelling grate member (7) in updraft mode at the agglomerate charge section (8) for cooling down the oxidized iron containing agglomerates (4), wherein the gaseous fluid (11 ) heated by the oxidized iron containing agglomerates (4) in said updraft mode subsequently is fed through the travelling grate member (7) in downdraft mode at the agglomerate discharge section (6) by means of said feeding device (FD); a control circuitry (50) adapted to control the operation of the straight-grate pelletizing apparatus (1 ); and the induration-cooler transition zone (TZ) comprises at least one gas inlet device (13’, 13”, 13’”) coupled to an oxygen supply (16) and adapted forinjecting an oxygen containing gas (15) into the gaseous fluid (11 ) for targeting the iron oxide containing agglomerates (2) subject to oxidization; the method is characterized by the steps of:-charging the iron oxide containing agglomerates (2) into the induration arrangement (3);-moving the iron oxide containing agglomerates (2) via the agglomerate discharge section (6) of the induration arrangement (3) to the agglomerate charge section (8) of the cooling arrangement (5);-feeding the gaseous fluid (11) from the gaseous fluid supply unit (9) through the travelling grate member (7) in updraft mode and in downdraft mode;-injecting the oxygen containing gas (15) into the gaseous fluid (11 ) by means of the at least one gas inlet device (13’, 13”, 13”’) providing that the gaseous fluid (11 ) injected with oxygen containing gas targets the iron oxide containing agglomerates (2) for enhancing the oxidization rate of magnetite material of the iron oxide containing agglomerates (2).

8. The method according to claim 7, wherein the step of injecting the oxygen containing gas (15) into the flow of the gaseous fluid (11 ) in said updraft mode is performed prior to the gaseous fluid (11 ) is fed through the travelling grate member (7).

9. The method according to claim 7 or 8, wherein the step of injecting the oxygen containing gas (15) into the flow of the gaseous fluid (11 ) in said downdraft mode is performed subsequently the gaseous fluid (11) has been fed through the travelling grate member (7).

10. The method according to any of claims 7 to 9, wherein the step of feeding the gaseous fluid (11 ) from the gaseous fluid supply unit (9) through the travelling grate member (7) in updraft mode comprises sealing a gap between a first carrier (20’) and a downdraft gaseous fluid passage channel, which first carrier (20’) is coupled to a second carrier (20”) and configured to carry the iron oxide containing agglomerates (2) subject to oxidization.11 . A data program (P), programmed with a program code adapted for causing the straight-grate pelletizing apparatus (1 ) according to any of the preceding claims to execute the method according to any of claims 7 to 10, wherein said data program (P) comprises a program code readable on a computer of the control circuitry (50) for providing the steps of any of claims 7 to 10.

12. The straight-grate pelletizing apparatus (1 ) according to any of claims 1 to 6, wherein a gaseous fluid transfer line arrangement (LA) is coupled to a wind box (19’) of an updraft gaseous fluid passage channel; a first and a second gas inlet device (14’, 14”) being positioned at sufficient distance from the wind box (19’) and upstream seen in the flow direction of the gaseous fluid (11 ) for allowing installation of a static mixer (SM) in the gaseous fluid transfer line arrangement (LA).

Images