Grate-kiln pelletizing apparatus and production method

Abstract

A method for production of and a grate-kiln pelletizing apparatus (1) for making oxidized iron containing agglomerates (3). A rotary kiln device (9) is adapted to sinter the oxidized iron containing agglomerates. An agglomerate transfer member (11) is coupled between a pre-heating device (5) and the rotary kiln device (9). A guide portion (13), such as a chute, is configured to guide the oxidized iron oxide containing material (7) to the rotary kiln device (9). The chute comprises at least one oxidation gas muzzle device (17) adapted for injecting an oxygen containing oxidation gas (19) into the iron oxide containing material for oxidizing un-oxidized iron oxide containing material moving along the guide portion (13).

Description

[0001] Grate-kiln pelletizing apparatus and production method

[0002] TECHNICAL FIELD

[0003] The present invention relates to a method of production of the oxidized iron containing agglomerates, which method is defined by claim 1 .

[0004] The present invention further relates to a grate-kiln pelletizing apparatus configured for production of oxidized iron containing agglomerates, which grate-kiln pelletizing apparatus is defined by the pre-characterizing part of claim 5. The present invention further relates to a data program, programmed with a program code adapted for causing the grate-kiln pelletizing apparatus to execute the method.

[0005] The present invention may concern the mining industry and / or the iron oxide production industry and / or the iron material making industry.

[0006] The present invention may concern metallurgical process industry producing oxidized iron containing pellets, such as iron oxide agglomerates or other types of iron oxide material.

[0007] The present invention also may concern manufacturers and suppliers of grate-kiln pelletizing apparatuses.

[0008] BACKGROUND

[0009] Oxidized iron containing agglomerates is produced by different types of grate-kiln pelletizing apparatuses configured to indurate (oxidize and / or sinter and / or heat treat) dried iron oxide containing material (e.g. so called green pellets).

[0010] Traditional methods of production of oxidized iron containing pellets are provided by means of a grate-kiln pelletizing apparatus, where crude iron ore extracted from the mine is up-graded by several steps, such as grinding, crushing, sizing and balling into green pellets before being introduced into the grate-kiln pelletizing apparatus.

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

[0012] The known grate-kiln pelletizing apparatus may be configured to move the iron oxide containing material by means of a travelling grate member, such as a continuous grate, through different zones for drying, induration (oxidization and sintering) and cooling down the material.

[0013] The induration may be defined as a process provided to oxidize and sinter the iron oxide containing material, wherein oxidizing of magnetite of the iron oxide containing material generally takes place in a pre-heating zone of the pre-heating device and eventually to some extent may take place in the rotary kiln device. Sintering of the iron oxide containing material generally takes place in the rotary kiln device.

[0014] Oxidizing of magnetite of the iron oxide containing material into hematite generates heat that can be used for the oxidization and / or sintering process.

[0015] Known grate-kiln pelletizing apparatuses 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 pre-heating zone of a pre-heating device for oxidizing the magnetite of the iron containing pellets into hematite.

[0016] However, known grate-kiln pelletizing apparatuses may be energy consuming and produce oxidized iron containing agglomerates having adversely affected properties and quality. Prior art grate-kiln pelletizing apparatuses also may produce large amount of CO2 and other non-environmental exhaust gases.

[0017] A further problem with grate-kiln pelletizing apparatuses of today is that they may not optimize the recovery of exhaust heat.

[0018] A yet further problem with prior art grate-kiln pelletizing apparatuses is that they may produce dust emissions due to insufficiently oxidized iron oxide containing material.

[0019] A yet further problem with prior art grate-kiln pelletizing apparatuses is that they may produce insufficiently oxidized iron oxide containing material, adversely affecting the quality of the produced oxidized iron containing agglomerates. Furthermore, a yet further problem with known grate-kiln pelletizing apparatuses is that they provide relatively low production rate due to not fully oxidized magnetite of the iron oxide containing material in the pre-heating zone.

[0020] SUMMARY OF THE INVENTION

[0021] There is an object to provide a grate-kiln pelletizing apparatus and a method of production of oxidized iron containing agglomerates by means of the grate-kiln pelletizing apparatus, wherein the production rate for production of oxidized iron containing agglomerates can be increased relative prior art productions rates.

[0022] There is an object to provide a grate-kiln 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 grate-kiln pelletizing apparatuses.

[0023] There is an object to provide a grate-kiln 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 oxidized iron containing agglomerates.

[0024] There is an object to provide a grate-kiln 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 current production costs for the production of oxidized iron containing agglomerates by means of prior art grate-kiln pelletizing apparatuses.

[0025] There is an object to provide a grate-kiln pelletizing apparatus and a method of production of oxidized iron containing agglomerates, wherein efficient control of heat energy content of the oxidized iron containing agglomerates fed from the pre-heating device to the rotary kiln device can be achieved.

[0026] There is an object to reduce fossil carbon emissions by decreasing or eliminating the use of coal or oil to heat the iron oxide containing material.

[0027] There is an object to sinter iron oxide containing agglomerates that has been subjected to oxidization, which sintering is to be provided by means of a rotary kiln device, in an energy saving manner for producing high quality oxidized iron containing agglomerates.

[0028] There is an object to develop prior art grate-kiln pelletizing apparatuses and prior art methods of production of oxidized iron containing agglomerates, such as iron oxide pellets.

[0029] This or at least one of said objects has been achieved by a method of production of oxidized iron containing agglomerates according to claim 1 .

[0030] An object is to provide a method of production of oxidized iron containing agglomerates, by means of a grate-kiln pelletizing apparatus, which comprises; a pre-heating device adapted to oxidize an iron oxide containing material comprising magnetite; a rotary kiln device adapted to sinter the oxidized iron containing agglomerates; an agglomerate transfer member coupled between the pre-heating device and the rotary kiln device; the agglomerate transfer member comprises a guide portion configured to guide an agglomerate bed, comprising oxidized iron containing agglomerates and iron oxide containing material to be oxidized, from the pre-heating device to the rotary kiln device; and the guide portion comprises at least one oxidation gas muzzle device adapted for injecting an oxygen containing oxidation gas into the agglomerate bed for oxidizing iron oxide containing material of the agglomerate bed moving along the guide portion; the method may be characterized by the steps of: moving the agglomerate bed toward the agglomerate transfer member; oxidizing the iron oxide containing material by introducing a process gas into the agglomerate bed comprising iron oxide containing material; guiding the agglomerate bed comprising iron oxide containing material along the guide portion; injecting the oxygen containing oxidation gas by means of the at least one oxidation gas muzzle device for oxidizing un-oxidized iron oxide containing material moving along the guide portion; charging the oxidized iron containing agglomerates into the rotary kiln device; sintering the oxidized iron containing agglomerates by means of the rotary kiln device; and discharging the oxidized iron containing agglomerates from the rotary kiln device.

[0031] The step of injecting the oxygen containing oxidation gas may be adapted to inject the oxygen containing oxidation gas in such way that the oxygen containing oxidation gas targets the magnetite of the iron oxide containing material subject to oxidization. The method may comprise the further step of introducing the oxygen containing oxidation gas through an oxygen containing oxidation gas channel of a sealing member arranged between the guide portion and an entrance portion of the rotary kiln device.

[0032] The method may comprise the further steps of; propelling the oxygen containing oxidation gas into the agglomerate bed in a first gas flow by means of a first fluid pump arrangement of a first fluid line set-up; propelling the process gas in a second gas flow by means of a second fluid pump arrangement of a second fluid line set-up for bringing along the oxygen containing oxidation gas in a counter-direction and / or in at least a counter-direction of the agglomerate bed moving along the guide portion.

[0033] The method may comprise the further step of; providing a low pressure region of the second fluid line set-up for providing down-draft of the process gas through a lower layer of the agglomerate bed and through a travelling grate member of the preheating device.

[0034] The low pressure region of the second fluid line set-up may be provided for providing down-draft of the process gas and the oxygen containing oxidation gas through the agglomerate bed supported by the travelling grate member.

[0035] The low pressure region of the second fluid line set-up may be provided for propelling the process gas in the second gas flow by means of the second fluid pump arrangement of the second fluid line set-up for bringing along the oxygen containing oxidation gas in a counter-direction and / or in at least a counter-direction of the agglomerate bed moving along the guide portion.

[0036] This or at least one of said objects has been achieved by means of a grate-kiln pelletizing apparatus according to any of the enclosed claims.

[0037] An object is to provide a grate-kiln pelletizing apparatus configured for production of oxidized iron containing agglomerates, which grate-kiln pelletizing apparatus comprises; a control circuitry adapted to control the production of oxidized iron containing agglomerates; a pre-heating device adapted to oxidize an iron oxide containing material comprising magnetite; a rotary kiln device adapted to sinter the oxidized iron containing agglomerates; an agglomerate transfer member coupled between the pre-heating device and the rotary kiln device. The agglomerate transfer member may comprise a guide portion configured to guide an agglomerate bed, comprising iron oxide containing material to be oxidized and / or oxidized iron containing agglomerates, from the pre-heating device to the rotary kiln device; and the guide portion comprises at least one oxidation gas muzzle device adapted for injecting an oxygen containing oxidation gas into the agglomerate bed for oxidizing iron oxide containing material of the agglomerate bed moving along the guide portion.

[0038] The guide portion may comprise at least one oxidation gas muzzle device adapted for injecting an oxygen containing oxidation gas into the agglomerate bed for oxidizing iron oxide containing material of the agglomerate bed moving along the guide portion for targeting the magnetite of the iron ore containing material subject to oxidization.

[0039] The guide portion may comprise at least one oxidation gas muzzle device adapted for injecting an oxygen containing oxidation gas into the agglomerate bed for oxidizing un-oxidized magnetite of the iron oxide containing agglomerate of the agglomerate bed moving along the guide portion.

[0040] The oxidation gas muzzle device may comprise a plurality of through holes extending through a chute wall of the guide portion.

[0041] The agglomerate transfer member may comprise a sealing member arranged between the guide portion and an entrance portion of the rotary kiln device.

[0042] The sealing member may comprise at least one oxygen containing oxidation gas channel adapted for injecting the oxygen containing oxidation gas into the agglomerate bed for oxidizing iron oxide containing material of the agglomerate bed that has moved along the guide portion.

[0043] The sealing member may comprise at least one oxygen containing oxidation gas channel adapted for injecting an oxygen containing oxidation gas into the agglomerate bed for oxidizing un-oxidized magnetite of the iron oxide containing agglomerate of the agglomerate bed that has moved along the guide portion.

[0044] The guide portion may slope from a discharge portion of the pre-heating device toward an entrance opening of the rotary kiln device.

[0045] The oxidation gas muzzle device may be coupled to an oxygen supply source. The grate-kiln pelletizing apparatus may comprise a first fluid pump arrangement of a first fluid line set-up coupled to the oxidation gas muzzle device, which may be configured to propel the oxygen containing oxidation gas into the agglomerate bed in a first gas flow.

[0046] A second fluid pump arrangement of a second fluid line set-up may be configured to propel a process gas in a second gas flow bringing along the oxygen containing oxidation gas in a counter-direction and / or in at least a counter-direction of the agglomerate bed moving along the guide portion.

[0047] A lower layer of the agglomerate bed comprises an iron oxide containing material that is supported by an agglomerate bed transport device of a travelling grate member, which agglomerate bed transport device may be configured to carry the agglomerate bed and which agglomerate bed transport device may extend along and within a pre-heating interior of the pre-heating device.

[0048] The control circuitry may be adapted to control the production of oxidized iron containing agglomerates based on the method steps according to any of the method claims; wherein the control circuitry may be electrically coupled to; a traveling grate driving motor arrangement for controlling the motion of the agglomerate bed through the pre-heating interior of the pre-heating device; and may be electrically coupled to a first fluid pump arrangement of a first fluid line set-up for controlling injection of the oxygen containing oxidation gas into the agglomerate bed in a first gas flow via the oxidation gas muzzle device; and may be electrically coupled to a second fluid pump arrangement of a second fluid line set-up for controlling the feeding of a process gas in a second gas flow for bringing along the oxygen containing oxidation gas in a direction opposite the moving direction of the agglomerate bed moving along the guide portion; and may be electrically coupled to a burner device of the rotary kiln device adapted to provide sintering of the oxidized iron containing agglomerates.

[0049] The control circuitry may be electrically coupled to a process gas heating device configured to heat the process gas to be down-drafted through the agglomerate bed for providing the oxidizing of the iron oxide containing material by means of the preheating device.

[0050] The control circuitry may be electrically coupled to a third fluid pump arrangement of a third fluid line set-up for controlling the feeding of the process gas into the rotary kiln device in a direction opposite the moving direction of the agglomerate bed moving through the rotary kiln device.

[0051] The second fluid pump arrangement may be configured for controlling the flow rate of the process gas for bringing along the oxygen containing oxidation gas in a counterdirection and / or in at least a counter-direction of the agglomerate bed moving along the guide portion.

[0052] This is solved by means of a data program, programmed for causing the grate-kiln pelletizing apparatus according to any of claims 5 to 14 to execute the method according to any of claims 1 to 4, wherein said data program comprises a program code readable on a computer of the control circuitry for causing the grate-kiln pelletizing apparatus to execute the method steps according to any of claims 1 to 4.

[0053] The second fluid pump arrangement may be controlled by the control circuitry to provide down-draft of the process gas through the agglomerate bed comprising iron oxide containing material to be oxidized.

[0054] The oxidation gas muzzle device may be adapted to inject the oxygen containing oxidation gas into the agglomerate bed passing the guide portion in such way that the oxygen containing oxidation gas targets iron oxide containing material of the agglomerate bed moving along the guide portion.

[0055] The injection of the oxygen containing oxidation gas into the agglomerate bed passing the guide portion may be performed in such way that the oxygen of the oxygen containing oxidation gas targets magnetite of the iron oxide containing material for enhancing the oxidization rate of magnetite of the iron oxide containing material.

[0056] In such way, the oxidized iron containing agglomerates (such as e.g. pellets) of the agglomerate bed are strengthened by the provision of fully oxidation of magnetite of the iron oxide containing material to hematite before the agglomerate bed is charged into the rotary kiln device, which is configured for e.g. sintering (thermal hardening and / or heat treatment) the fully oxidized iron containing agglomerates.

[0057] In such way is achieved complete oxidization of the magnetite before the agglomerates are charged into the rotary kiln device configured for sintering the agglomerates, which otherwise would require further energy and slowing down the production rate.

[0058] By means of sintering the fully oxidized iron containing agglomerates in the rotary kiln device, there is no energy to be used in the rotary kiln device for further oxidization of the material in the rotary kiln device.

[0059] In such way, any iron oxide containing material of the agglomerate bed not being fully oxidized, when leaving the pre-heating device, will be completely oxidized by means of the guide portion comprising the oxidation gas muzzle device adapted for injecting the oxygen containing oxidation gas into the agglomerate bed for oxidizing iron oxide containing material (magnetite) of the agglomerate bed moving along the guide portion.

[0060] This will in turn increase the heat content of the agglomerate bed being charged into the rotary kiln device. In such way, the sintering of the oxidized iron containing agglomerates in the rotary kiln device requires less heating energy than prior art for sintering the oxidized iron containing agglomerates for the production of oxidized iron containing agglomerates, which in turn is energy saving.

[0061] The oxidation of magnetite FesC into hematite Fe2Os is an exothermic chemical reaction thus generating heat. Energy in the form of heat is released during the oxidation process of the iron oxide containing material (comprising magnetite) since chemical bonds are broken and reformed in the new compound (oxidized iron containing agglomerates comprising hematite). The amount of heat produced during this chemical reaction may vary depending on the specific design of the grate-kiln pelletizing apparatus and the oxidation rate. The oxidation of magnetite FesC into hematite Fe2Os thus involves a change in the chemical composition, which may be expressed by the following chemical equation:

[0062] 4FesO4 + O2 -> 6Fe20s + heat

[0063] This chemical equation shows that magnetite combined with oxygen (contained in the oxygen containing oxidation gas) forms hematite and generates heat (exothermic chemical reaction). The pre-heating device may be configured to successively oxidize the iron oxide containing material through the agglomerate bed from top-down by means of the down-draft of the process gas transferred into the pre-heating device.

[0064] The down-draft of the process gas through the agglomerate bed may involve that the process gas is drawn through (from) an upper layer of the agglomerate bed toward the lower layer of the agglomerate bed.

[0065] The down-draft of the process gas through the agglomerate bed may involve that the process gas is drawn further down through the travelling grate member of the preheating device.

[0066] The process gas may be added with oxygen containing oxidation gas before being down-draft through the agglomerate bed.

[0067] The travelling grate member may comprise; an agglomerate bed transport device, such as a conveyor belt, a plurality of iron oxide containing material cars or any other type of agglomerate bed transport device, configured to move the iron oxide containing material in the pre-heating interior of the pre-heating device while the down-draft of the process gas is performed for oxidization of the iron oxide containing material.

[0068] The agglomerate bed transport device may be configured to carry the iron oxide containing material to be oxidized, wherein a lower layer of the agglomerate bed is supported by a support surface of the agglomerate bed transport device.

[0069] The guide portion may comprise an upper portion and a lower portion.

[0070] A discharge portion of the agglomerate bed transport device may be configured to discharge the agglomerate bed to the upper portion of the guide portion of the agglomerate transfer member.

[0071] The support surface may comprise through holes or openings configured to allow the down-draft of the process gas through the agglomerate bed supported by the support surface and through the agglomerate bed transport device.

[0072] The traveling grate driving motor arrangement may be configured to drive the agglomerate bed transport device along and within the pre-heating interior. The traveling grate driving motor arrangement may comprise a traveling grate driving motor and an agglomerate bed transport device position sensor device, which are electrically coupled to the control circuitry.

[0073] The first fluid line set-up may comprise a first gas flow regulating unit configured for regulating the flow rate of the oxygen containing oxidation gas fed by the first fluid pump arrangement through the oxidation gas muzzle device and injected into the agglomerate bed.

[0074] The oxidation gas muzzle device may comprise the first gas flow regulating unit.

[0075] The first fluid line set-up may comprise an oxygen source supply configured to store pure oxygen.

[0076] The first fluid line set-up may comprise an air supply line configured to feed air to be mixed with pure oxygen for providing the oxygen containing oxidation gas.

[0077] The first fluid line set-up may comprise a mixing valve arrangement configured to provide the oxygen containing oxidation gas with a specific content of oxygen of the oxygen containing oxidation gas.

[0078] The first gas flow regulating unit and / or an oxidation gas detecting sensor device of the first fluid line set-up and / or the mixing valve arrangement and / or the first fluid pump arrangement may be electrically coupled to the control circuitry.

[0079] The oxidation gas detecting sensor device may be adapted to detect the actual oxygen content of the oxygen containing oxidation gas.

[0080] The second fluid pump arrangement may comprise a second gas flow regulating unit configured for regulating the flow rate of the process gas fed into the pre-heating interior of the pre-heating device, which process gas may be drawn down through the agglomerate bed by means of the second fluid pump arrangement in purpose to oxidize the iron oxide containing material.

[0081] The second gas flow regulating unit and a process gas detecting sensor device of the second fluid pump arrangement may be electrically coupled to the control circuitry.

[0082] The process gas detecting sensor device may be adapted to detect the actual oxygen content of the process gas. The second fluid line set-up may comprise a process gas pre-heating device configured for pre-heating the process gas before being fed into the pre-heating interior.

[0083] The pre-heated process gas may be produced by passing the rotary kiln device in a counter-direction of the agglomerate bed moving through the rotary kiln device.

[0084] A kiln burner member of the rotary kiln device may be configured to fire the oxidized iron containing agglomerates for providing sintering the oxidized iron containing agglomerates in the rotary kiln device.

[0085] The pre-heated process gas may be produced by passing the kiln burner member of the rotary kiln device in a counter-direction of the agglomerate bed moving along the rotary kiln device.

[0086] The process gas pre-heating device may comprise an electrical heater and / or a burner unit and may be electrically coupled to the control circuitry for controlling the thermal energy of the process gas fed into the pre-heating interior.

[0087] In such way is achieved a uniform homogenous structure of of the oxidized iron containing agglomerates of the produced pellets without any cracks and microsructure defects.

[0088] Current grate-kiln pelletizing apparatuses may produce pellets with cracks, breaks in the outer layer of the pellets.

[0089] Current grate-kiln pelletizing apparatuses may provide pellets with lower compression strengths of the outer layers of the pellets by that the outer layer of the pellets oxidizes first (i.e. magnetite oxides to hematite) and subsequently sinters, whereas the core of the pellets sinters first and then oxidizes, which will result in an inhomogeneous structure of the pellets. Such inhomogeneous structure would in turn cause stresses of the pellet structure resulting in cracks and discontinuities in the core of the pellets, which in turn decrease the compression strength of the pellets.

[0090] The travelling grate member may be configured to move the agglomerate bed of agglomerates of iron oxide containing material to be oxidized through the pre-heating interior of the pre-heating device for oxidizing of the iron oxide containing material. The agglomerate bed may be applied to the support surface of the agglomerate bed transport device of the travelling grate member, wherein a lower layer of the agglomerate bed of agglomerates of iron oxide containing material to be oxidized may be supported by the travelling grate member.

[0091] The pre-heating device may be adapted to oxidize the iron oxide containing material by introducing a flow of hot oxidizing gas into the pre-heating interior of the preheating device.

[0092] The flow of hot oxidizing gas may be drawn downward through the agglomerate bed comprising the iron oxide containing material and further through the travelling grate member.

[0093] The agglomerate bed may be conveyed through drying zones for drying the iron oxide containing material being in the form of wet iron ore pellets (so called green pellets).

[0094] Subsequently, the dried iron ore containing material may be fed through the preheating zone, which aims to oxidize the iron oxide containing material.

[0095] Subsequently, the iron ore may be guided via a chute member of the guide portion to the rotary kiln device for firing and sintering the oxidized iron containing agglomerates in the rotary kiln device.

[0096] Subsequently, the oxidized and sintered iron containing material may be fed into a cooler zone of the cooler device for cooling the oxidized (indurated) iron containing material.

[0097] At least one drying zone may be fed with hot air re-circulated from the cooler zone of the grate-kiln pelletizing apparatus for drying the green pellets in the drying zone.

[0098] A pre-heated process gas may be re-circulated from the rotary kiln device to the preheating zone and may be fed downwardly through the agglomerate bed of iron oxide containing material in the pre-heating zone for oxidizing the dried iron oxide containing material.

[0099] The grate-kiln pelletizing apparatus may comprise an electrolysis unit configured to produce oxygen and hydrogen. The oxygen produced by the electrolysis unit may be transferred to the at least one oxidation gas muzzle device for oxidizing eventually iron oxide containing material leaving the agglomerate bed transport device.

[0100] The hydrogen produced by the electrolysis unit may be fed to a hydrogen burner device (kiln burner member) of the rotary kiln device.

[0101] In such way, a lower layer of the agglomerate bed comprising iron oxide containing material, previously supported by the agglomerate bed transport device of the travelling grate member, will be targeted by the oxygen containing oxidation gas injected by means of the oxidation gas muzzle device.

[0102] This or at least one of said objects has been achieved by a data program according to claim 15.

[0103] The wording “iron oxide containing material” may be defined as an iron material comprising hematite and / or magnetite and / or wustite and / or other materials and / or compositions and / or minerals.

[0104] The wording “oxidized iron containing agglomerates” may also be defined as an inorganic compound of agglomerates, such as hematite with the formula Fe2Os, wherein the grate-kiln pelletizing apparatus may be configured for production of oxidized iron ore containing material (production of iron oxide pellets comprising hematite).

[0105] The wording “oxidized iron containing agglomerates” may be defined as an iron material that comprises a larger content of hematite than in the iron oxide containing agglomerates.

[0106] The wording “iron oxide containing agglomerates” (e.g. green pellets) may define an iron oxide containing material comprising iron oxides (such as magnetite) and / or other minerals and / or gangue or other impurities.

[0107] The induration temperature and time required for induration (heat treatment and / or heat hardening) depend on the mineralogy of the iron ore of the iron oxide containing agglomerates, as well as binder type and amount of the agglomerates. The grate-kiln pelletizing apparatus may rely on carrying the agglomerate bed through a number of thermal zones by means of the agglomerates transport device by moving a perforated grate and through a rotary kiln device.

[0108] The term “induration” may be replaced by the word “heat hardening and / or heat treatment”.

[0109] The induration arrangement may comprise an induration zone configured to indurate (heat treat) the iron oxide containing agglomerates.

[0110] The induration zone may comprise a section of the cooling zone configured to cool down the oxidized iron containing agglomerates.

[0111] The induration zones of the grate kiln iron oxide pelletizing configuration may be defined to comprise several heat-treatment zones: drying zones; pre-heating zones (tempered pre-heating and preheating zones) and heating zone (rotary kiln device) and / or cooling zones of the cooler device.

[0112] The grate-kiln pelletizing apparatus configured for production of oxidized iron containing agglomerates may comprise the pre-heating device of an induration arrangement configured to oxidize (heat treat) an iron oxide containing material comprising magnetite. The cooling zone configured to cool down the oxidized iron containing agglomerates may be regarded to fully or partly belong to the induration arrangement.

[0113] There is thus achieved that the pellet bed or agglomerate bed will have higher thermal energy than that of 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.

[0114] The oxygen containing oxidation gas may be set by means of the control circuitry to exhibit a temperature by means of a heating device and / or flow rate by means of a feeding device, for causing the iron oxide containing material subjected to be oxidized (and / or sintered and / or heat treated) to exhibit a desired temperature.

[0115] The oxygen containing oxidation gas may be pre-heated by a heating device controlled by the control circuitry to exhibit a raised temperature of the oxygen containing oxidation gas. The temperature of the oxygen containing oxidation gas meeting the heated agglomerate bed may be raised by the heated agglomerate bed thus promoting efficient oxidization of the magnetite.

[0116] The oxygen containing oxidation gas injected via the guide portion may be provided to target the magnetite of the iron oxide containing material subject to oxidization.

[0117] The oxygen containing oxidation gas fed via the guide portion into the agglomerate bed may be pre-heated.

[0118] The oxygen content of the oxygen containing oxidation gas may be controlled by the control circuitry to exhibit a (desired) content of oxygen set by means of the control circuitry.

[0119] The oxygen content of the oxygen containing oxidation gas may be controlled by the control circuitry by controlling the flow rate of the oxygen containing oxidation gas fed via the agglomerate transfer member into the agglomerate bed.

[0120] The control circuitry may be adapted to cause the iron oxide containing material subjected to be oxidized (and / or sintered and / or heat treated) 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.

[0121] By means of the oxygen containing oxidation gas there is provided higher oxidation rate of the magnetite of the iron oxide containing agglomerates under oxidation versus prior art configurations. The oxygen containing oxidation gas may be controlled to comprise a desired content of oxygen by means of the control circuitry coupled to the at least one oxidation gas muzzle device for controlling and / or regulating the amount of oxygen of the oxygen containing oxidation gas, wherein the oxygen containing oxidation gas 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.

[0122] By means of the oxygen containing oxidation gas targeting the magnetite, the agglomerate bed will be efficiently and / or completely oxidated.

[0123] In such way is achieved that the agglomerate bed will be completely oxidized, wherein the high oxygen content of the oxygen containing oxidation gas injected for oxidizing iron oxide containing agglomerates moving along the guide portion provides an energy efficient oxidization of the magnetite.

[0124] In such way is achieved that the production rate can be increased due to a more energy effective oxidization process for oxidizing the magnetite at the same time as the quality of the oxidized iron containing agglomerates is enhanced.

[0125] In such way there is achieved that the oxidation rate of the magnetite of the iron oxide containing material for production of the iron oxide containing material is increased relative prior art grate-kiln pelletizing apparatuses.

[0126] In such way there is achieved that the production rate is increased relative prior art grate-kiln pelletizing apparatuses.

[0127] In such way the gaseous fluid injected with oxygen can be used as a cooling medium for cooling the oxidized iron containing agglomerates. The oxidation gas muzzle device may comprise a first and a second oxygen containing oxidation gas injection device, the second oxygen containing oxidation gas injection device is configured to inject a larger quantity of oxygen through an upper portion of the guide portion next to the pre-heating device than that injected further down through the guide portion.

[0128] The guide portion comprises at least one oxidation gas muzzle device adapted for injecting an oxygen containing oxidation gas, such as air, into and / or through the agglomerate bed for oxidizing magnetite of the iron oxide containing agglomerates of the agglomerate bed moving along the guide portion.

[0129] The oxygen containing oxidation gas may be heated by a heating member, such as a gas burner, electrical heater, plasma heater, etc., before being injected into and / or through the agglomerates of the agglomerate bed moving along the guide portion.

[0130] In such way is achieved that oxygen fed through the guide portion and that has not reacted with the iron oxide containing agglomerates moving along the guide portion, can be led to the pre-heating device nearest to the guide portion (i.e. the very last part of the pre-heating device seen in the agglomerate transport direction) in an effective way without being disturbed by the very high flow of process gas fed through the rotary kiln device.

[0131] This promotes effective oxidizing of the bottom layer of the iron oxide containing agglomerate bed moved in the very last part of the pre-heating device.

[0132] The moving iron oxide containing agglomerate bed in the machine upstream of the very last part of the pre-heating device seen in transport direction is heated and oxidised from above (from the top layer of the iron oxide containing agglomerate bed) toward the bottom layer of the iron oxide containing agglomerate bed. That is, in the very last part of the pre-heating device, the bottom layer of the iron oxide containing agglomerate bed has reached high temperature suitable for further oxidization and the oxygen led to the pre-heating device nearest to the guide portion and via the guide portion ensures that effective oxidization of the bottom layer of the iron oxide containing agglomerate bed is achieved in the very last part of the pre-heating device. 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 meaning of the appended claims.

[0133] BRIEF DESCRIPTION OF THE DRAWINGS

[0134] The present invention will now be described by way of examples with references to the accompanying schematic drawings, of which:

[0135] Fig. 1 illustrates a grate-kiln pelletizing apparatus according to a first example;

[0136] Fig. 2 illustrates a grate-kiln pelletizing apparatus according to a second example;

[0137] Fig. 3 illustrates a guide portion of a grate-kiln pelletizing apparatus according to a third example shown in a view from a rotary kiln device;

[0138] Fig. 4 illustrates a grate-kiln pelletizing apparatus according to a fourth example;

[0139] Fig. 5 illustrates an oxidation gas muzzle device of a chute wall of guide portion of a grate-kiln pelletizing apparatus according to a fifth example;

[0140] Fig. 6 illustrates a sealing member of a grate-kiln pelletizing apparatus according to a sixth example;

[0141] Fig. 7 illustrates a flowchart showing an exemplary method of production of oxidized iron containing agglomerates by means of a grate-kiln pelletizing apparatus;

[0142] Fig. 8 illustrates a flowchart showing an exemplary method of production of oxidized iron containing agglomerates by means of a grate-kiln pelletizing apparatus;

[0143] Fig. 9 illustrates a control circuitry of a grate-kiln pelletizing apparatus according to a further example;

[0144] Fig. 10a shows a part of a grate-kiln pelletizing apparatus 1 configured for production of oxidized iron containing agglomerates according to a further example; and

[0145] Fig. 10b shows a part of a grate-kiln pelletizing apparatus 1 configured for production of oxidized iron containing agglomerates according to a yet further example. DETAILED DESCRIPTION

[0146] 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 figures.

[0147] Fig. 1 illustrates a grate-kiln pelletizing apparatus 1 according to a first example. The grate-kiln pelletizing apparatus 1 is configured for production of oxidized iron containing agglomerates 3 (may be called indurated iron containing material). The grate-kiln pelletizing apparatus 1 comprises a control circuitry 50 adapted to control the production of oxidized iron containing agglomerates 3.

[0148] The control circuitry 50 may be adapted to control the flow of a process gas 43 fed into a pre-heating interior PH of a pre-heating device 5 of the grate-kiln pelletizing apparatus 1 for oxidization of an iron oxide containing material 7 fed into the preheating device 5. The pre-heating device 5 is adapted to oxidize the iron oxide containing material 7 comprising magnetite.

[0149] The grate-kiln pelletizing apparatus 1 further comprises a rotary kiln device 9 adapted to sinter the oxidized iron containing agglomerates. The rotary kiln device 9 may comprise a burner 63 (such as a hydrogen burner), which may be adapted to provide sintering of the oxidized iron containing agglomerates.

[0150] The grate-kiln pelletizing apparatus 1 further comprises an agglomerate transfer member 11 coupled between the pre-heating device 5 and the rotary kiln device 9 for transferring the oxidized iron containing agglomerates and eventually iron oxide containing material 7 from the pre-heating device 5 to the rotary kiln device 9.

[0151] The control circuitry 50 may further be adapted to control the flow of the process gas 43 fed through the rotary kiln device 9 and into a pre-heating interior PH of the preheating device 5 and / or fed to target eventually iron oxide containing material guided along the agglomerate transfer member 11 . The control circuitry 50 may be electrically coupled to a traveling grate driving motor arrangement 61 for controlling the motion of the agglomerate bed through the pre-heating interior PH. The agglomerate transfer member 11 comprises a guide portion 13 (such as a chute) configured to guide an agglomerate bed (not shown), comprising the iron oxide containing material 7 to be oxidized and / or oxidized iron containing agglomerates, from the pre-heating device 5 to the rotary kiln device 9. The guide portion 13 comprises at least one oxidation gas muzzle device 17 of the guide portion 13, which muzzle device 17 is adapted for injecting an oxygen containing oxidation gas 19 into the agglomerate bed for oxidizing eventually un-oxidized iron oxide containing material of the agglomerate bed moving along the guide portion 13. The oxidation gas muzzle device 17 may comprise a plurality of through holes 21 extending through a chute wall 23 of the guide portion 13. The oxidation gas muzzle device 17 is coupled to an oxygen supply source 33. The guide portion 13 slopes from a discharge portion 31 of the pre-heating device 5 toward an entrance opening of the rotary kiln device 9.

[0152] The grate-kiln pelletizing apparatus 1 comprises a fluid pump arrangement 35 of a gas line 37 coupled to the at least one oxidation gas muzzle 17 and configured to propel the oxygen containing oxidation gas into the agglomerate bed 15 sliding along the agglomerate transfer member 11 .

[0153] A gas pump 39 is configured to propel a process gas 43 in counter-direction and / or in at least a counter-direction relative the motion direction of the agglomerate bed 15 sliding along the guide portion 13, which process gas 43 has a flow bringing the injected oxygen containing oxidation gas 19 along and / or propelling the injected oxygen containing oxidation gas 19 within the agglomerate bed in a counter-direction relative the motion direction of the agglomerate bed 15.

[0154] Fig. 2 illustrates a grate-kiln pelletizing apparatus 1 according to a second example. The grate-kiln pelletizing apparatus 1 is configured for production of oxidized iron containing agglomerates. The grate-kiln pelletizing apparatus 1 comprises a control circuitry (not shown) adapted to control the production of oxidized iron containing agglomerates 3. A pre-heating device 5 is adapted to oxidize an iron oxide containing material 7 comprising magnetite. A rotary kiln device 9 is adapted to sinter the oxidized iron oxide containing material 7. An agglomerate transfer member 11 is coupled between the pre-heating device 5 and the rotary kiln device 9. The agglomerate transfer member 11 comprises a guide portion, such as a chute, configured to guide an agglomerate bed 15, comprising the iron oxide containing material 7 to be oxidized and / or oxidized iron containing agglomerates, from the preheating device 5 to the rotary kiln device 9.

[0155] The guide portion comprises at least one oxidation gas muzzle device (not shown) adapted for injecting an oxygen containing oxidation gas 19 into the agglomerate bed 15 sliding along the guide portion for oxidizing un-oxidized iron oxide containing material of the agglomerate bed 15 moving along the guide portion. The grate-kiln pelletizing apparatus 1 comprises a first fluid pump arrangement 35 of a first fluid line set-up coupled to the at least one oxidation gas muzzle device and configured to propel the oxygen containing oxidation gas in the agglomerate bed 15 according to a first gas flow (not shown) sliding along the guide portion. A second fluid pump arrangement 39 of a second fluid line set-up 41 configured to propel a process gas 43 in a second gas flow d2 bringing along the oxygen containing oxidation gas in a counter-direction and / or in at least a counter-direction of the motion of the agglomerate bed 15 sliding along the guide portion in a direction d3. There is proved a low pressure region LPR of the second fluid line set-up 41 for providing down-draft of the process gas 43 through a lower layer (not shown) of the agglomerate bed 15 and through a travelling grate member (not shown) of the pre-heating device 5.

[0156] A third fluid pump arrangement 67 of a third fluid line set-up 69 may be arranged for controlling feeding of yet a further process gas 43 into the rotary kiln device 9 in a direction opposite the moving direction of the agglomerate bed 15 moving through the rotary kiln device 9.

[0157] The second fluid pump arrangement 39 for controlling the flow rate of the process gas 43 for bringing along the oxygen containing oxidation gas 19 in a counterdirection and / or in at least a counter-direction of the motion direction d3 of the agglomerate bed 15 moving along the guide portion 13.

[0158] The control circuitry may be electrically coupled to a process gas heating device 65 configured to heat the process gas 43 to be down-drafted through the agglomerate bed 15 for providing the oxidizing of the iron oxide containing material 7 by means of the pre-heating device 5.

[0159] Fig. 3 illustrates a guide portion 13 of an agglomerate transfer member 11 of a gratekiln pelletizing apparatus according to a third example shown in a view from a rotary kiln device. The guide portion 13 is configured to guide an agglomerate bed (not shown), comprising oxidized iron containing agglomerates and iron oxide containing agglomerates to be oxidized, from the pre-heating device to the rotary kiln device (not shown).

[0160] The guide portion 13 comprises at least one oxidation gas muzzle device 17 adapted for injecting an oxygen containing oxidation gas (not shown) into the agglomerate bed (not shown) for oxidizing eventually un-oxidized iron oxide containing material of the agglomerate bed moving along the guide portion 13. The oxidation gas muzzle device 17 comprises a plurality of through holes 21 extending through a chute wall 23 of the guide portion 13. The through holes 21 are coupled for fluid communication with a fluid pump arrangement (not shown) of a fluid line set-up (not shown), which fluid pump arrangement is configured to propel the oxygen containing oxidation gas into the agglomerate bed (not shown).

[0161] Fig. 4 illustrates a grate-kiln pelletizing apparatus 1 according to a fourth example. The grate-kiln pelletizing apparatus 1 is configured for production of oxidized iron containing agglomerates 3. A control circuitry (not shown) may be adapted to control the flow of a process gas 43 fed into a pre-heating interior PH of a pre-heating device 5 for oxidization of an iron oxide containing material 7 of an agglomerate bed 15 comprising the iron oxide containing material 7. The grate-kiln pelletizing apparatus 1 further comprises a rotary kiln device 9 adapted to sinter the oxidized iron containing agglomerates. A lower layer 45 of the agglomerate bed 15 comprising iron oxide containing material 7 to be oxidized is supported by an agglomerate bed transport device AD of a travelling grate member 47.

[0162] A guide portion (e.g. a chute) 13 of an agglomerate transfer member 11 is configured to guide the agglomerate bed 15 from the pre-heating device 5 to the rotary kiln device 9. The guide portion 13 comprises at least one oxidation gas muzzle device 17 adapted for injecting an oxygen containing oxidation gas 19 into the agglomerate bed 15 sliding over the guide portion 13.

[0163] The grate-kiln pelletizing apparatus 1 may comprise an electrolysis unit Ell configured to produce oxygen and hydrogen. The oxygen may be transferred to the at least one oxidation gas muzzle device 17 for oxidizing eventually un-oxidized iron oxide containing material leaving the agglomerate bed transport device AD to be fed into the rotary kiln device 9. The hydrogen produced by the electrolysis unit Ell may be fed to a burner device (hydrogen burner device, not shown) of the rotary kiln device 9. The electrolysis unit Ell may be configured to separate the hydrogen and the oxygen from water by means of electricity, which entirely or at least to some extent is produced by renewable energy sources.

[0164] The grate-kiln pelletizing apparatus 1 may comprise an oxygen generator configured to separate oxygen from nitrogen and other components of air. The oxygen may be transferred to the at least one oxidation gas muzzle device 17. The oxidation gas muzzle device 17 is coupled to an oxygen supply source 33.

[0165] The electrolysis unit is configured to separate hydrogen and oxygen from water by means of electricity, which entirely or at least to some extent is produced by renewable energy sources.

[0166] The lower layer 45 of the agglomerate bed 15 comprising iron oxide containing material 7 is supported by the agglomerate bed transport device AD, which extends along and within a pre-heating interior PH of the pre-heating device 5.

[0167] A control circuitry (not shown) may be adapted to control the production of oxidized iron containing agglomerates 3. The control circuitry may be electrically coupled to; a traveling grate driving motor arrangement (not shown) for controlling the motion of the agglomerate bed 15 through the pre-heating interior PH; a first fluid pump arrangement (not shown) of a first fluid line set-up 37 for controlling injection of the oxygen containing oxidation gas 19 into the agglomerate bed 15 in a first gas flow d1 via the oxidation gas muzzle device 17; a second fluid pump arrangement 39 of a second fluid line set-up 41 for controlling the feeding of the process gas 43 in a second gas flow d2 for bringing along the oxygen containing oxidation gas 19 in a direction opposite the moving direction of the agglomerate bed 15 moving along the guide portion 13; and the burner device of the rotary kiln device 9.

[0168] The lower layer 45 of the agglomerate bed 15 comprising iron oxide containing material 7 is supported by the agglomerate bed transport device AD, which extends along and within a pre-heating interior PH of the pre-heating device 5.

[0169] The second fluid pump arrangement 39 for controlling the flow rate of the process gas 43 for bringing along the oxygen containing oxidation gas 19 in a counter- direction and / or in at least a counter-direction of the motion direction d3 of the agglomerate bed 15 moving along the guide portion 13.

[0170] Fig. 5 illustrates an oxidation gas muzzle device of a chute wall 23 of a guide portion 13 of a grate-kiln pelletizing apparatus according to a fifth example. The guide portion 13 comprises an oxidation gas muzzle 17 adapted for injecting an oxygen containing oxidation gas 19 into the agglomerate bed 15 for oxidizing eventually un-oxidized iron oxide containing material of the agglomerate bed 15 moving along the guide portion 13.

[0171] The flow of the process gas 43 brings along the oxygen containing oxidation gas 19 within the agglomerate bed 15 and in a counter-direction and / or in at least a counterdirection of the motion direction d3 of the agglomerate bed 15 moving along the guide portion 13.

[0172] Fig. 6 illustrates a sealing member 25 of a grate-kiln pelletizing apparatus according to a sixth example. A lower portion of an agglomerate transfer member 11 is coupled to a kiln wall portion forming an entrance portion 27 of a rotary kiln device 9. The agglomerate transfer member 11 comprises the sealing member 25 arranged between a guide portion 13 of the agglomerate transfer member 11 and the entrance portion 27 of the rotary kiln device 9. The sealing member 25 comprises at least one oxygen containing oxidation gas channel 29 adapted for injecting an oxygen containing oxidation gas 19 into the agglomerate bed for oxidizing un-oxidized iron oxide containing material of the agglomerate bed moving into the rotary kiln device 9.

[0173] Fig. 7 illustrates a flowchart showing an exemplary method of production of oxidized iron containing agglomerates by means of a grate-kiln pelletizing apparatus, which comprises a pre-heating device adapted to oxidize an iron oxide containing material comprising magnetite; a rotary kiln device adapted to sinter the oxidized iron containing agglomerates; an agglomerate transfer member coupled between the preheating device and the rotary kiln device; the agglomerate transfer member comprises a guide portion configured to guide an agglomerate bed, comprising oxidized iron containing agglomerates and iron oxide containing material to be oxidized, from the pre-heating device to the rotary kiln device; and the guide portion comprises at least one oxidation gas muzzle device adapted for injecting an oxygen containing oxidation gas into the agglomerate bed for oxidizing un-oxidized iron oxide containing material of the agglomerate bed moving along the guide portion. The method in Fig. 7 starts at step 901 . Step 902 performs the method. Step 903 stops the method.

[0174] Step 902 may comprise the steps of; moving the agglomerate bed toward the agglomerate transfer member; oxidizing the iron oxide containing material by introducing a process gas into the agglomerate bed comprising iron oxide containing material ; guiding the agglomerate bed comprising un-oxidized iron oxide containing material along the guide portion; injecting the oxygen containing oxidation gas by means of the at least one oxidation gas muzzle device for oxidizing un-oxidized iron oxide containing material moving along the guide portion; charging the oxidized iron containing agglomerates into the rotary kiln device; sintering the oxidized iron containing agglomerates by means of the rotary kiln device; and discharging the oxidized iron containing agglomerates from the rotary kiln device.

[0175] Fig. 8 illustrates a flowchart showing an exemplary method of production of oxidized iron containing agglomerates by means of a grate-kiln pelletizing apparatus. The method starts at step 111. Step 112 may comprise moving the agglomerate bed toward the agglomerate transfer member. Step 113 may comprise oxidizing the iron oxide containing material by introducing a process gas into the agglomerate bed comprising iron oxide containing material. Step 114 may comprise guiding the agglomerate bed comprising un-oxidized iron oxide containing material along the guide portion. Step 115 may comprise injecting the oxygen containing oxidation gas by means of the at least one oxidation gas muzzle device for oxidizing un-oxidized iron oxide containing material moving along the guide portion. Step 116 may comprise charging the oxidized iron containing agglomerates into the rotary kiln device. Step 117 may comprise sintering the oxidized iron containing agglomerates by means of the rotary kiln device. Step 118 may comprise discharging the oxidized iron containing agglomerates from the rotary kiln device. Step 119 may stop the method.

[0176] The method may comprise propelling the oxygen containing oxidation gas into the agglomerate bed in a first gas flow by means of a first fluid pump arrangement of a first fluid line set-up. The method may comprise propelling the process gas in a second gas flow by means of a second fluid pump arrangement of a second fluid line set-up for bringing along the oxygen containing oxidation gas in a counter-direction and / or in at least a counter-direction of the agglomerate bed moving along the guide portion.

[0177] The method may comprise providing a low pressure region of the second fluid line set-up for providing down-draft of the process gas through a lower layer of the agglomerate bed and through a travelling grate member of the pre-heating device.

[0178] Fig. 9 illustrates a control circuitry 50 of a grate-kiln pelletizing apparatus according to a further example. The control circuitry 50 comprises a computer (not shown) and is configured to control any exemplary method herein disclosed.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] The signals may be sent from a temperature sensor member 66 for detecting temperatures of the iron oxide containing material subject to oxidization and the temperature of the oxidized iron containing agglomerates ready for cooling and / or for detecting temperatures of injected oxygen and / or the temperature of oxygen targeting the iron oxide containing material subject to oxidization. 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 gas and / or the oxygen content of the gaseous fluid.

[0184] The control circuitry 50 may be electrically coupled to said temperature sensor members and adapted to control the oxidation gas muzzle device for regulating the content the oxygen in the process gas and / or the oxygen containing oxidation gas following the gaseous fluid.

[0185] 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 oxidization of the iron oxide containing material and adaption of the oxidization for reaching efficient oxidization of magnetite to hematite.

[0186] 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.

[0187] A data medium adapted for storing a data program P may comprise driver routines adapted for commanding the operating of the grate-kiln pelletizing apparatus 1 .

[0188] 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 grate-kiln pelletizing apparatus 1 for achieving any of the exemplary methods herein disclosed.

[0189] The data program P comprises a program code, which is readable on the computer, for causing the computer to control the grate-kiln pelletizing apparatus 1 to perform an exemplary method herein described.

[0190] 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.

[0191] 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. 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).

[0192] In such way is achieved that an operator via a display of the electronic control circuitry can control and monitor the grate-kiln pelletizing apparatus 1 .

[0193] 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.

[0194] 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.

[0195] The signals -received by the signal (data) port 999- may also comprise information about operational status of the grate-kiln pelletizing apparatus 1 .

[0196] 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.

[0197] The signals received by the signal (data) port 999 may also be used for historic data and data regarding operation of the grate-kiln pelletizing apparatus 1 .

[0198] The grate-kiln 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.

[0199] The data may include information about status of the grate-kiln 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. 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 grate-kiln pelletizing apparatus 1 .

[0200] The data program P is programmed with a program code adapted for causing an exemplary grate-kiln pelletizing apparatus 1 to execute any exemplary method herein disclosed.

[0201] 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 grate-kiln pelletizing apparatus 1 to perform any of the exemplary method steps herein disclosed, when the data program P is run on the computer.

[0202] Fig. 10a shows a part of a grate-kiln pelletizing apparatus 1 configured for production of oxidized iron containing agglomerates (not shown). The grate-kiln pelletizing apparatus 1 comprises a control circuitry 50 set to control the production of oxidized iron containing agglomerates. A pre-heating device 5 is provided to oxidize an iron oxide containing material 7 comprising magnetite. A rotary kiln 9 is provided to sinter oxidized iron containing agglomerates fed from the pre-heating device to the rotary kiln 9 via an agglomerate transfer member 11 coupled between the pre-heating device 5 and the rotary kiln 9.

[0203] The agglomerate transfer member 11 comprises a material guide portion 13 (such as a chute) configured to guide an agglomerate bed (not shown), comprising iron oxide containing material not yet oxidized but subject to be oxidized and / or oxidized iron containing agglomerates, from the pre-heating device 5 to the rotary kiln device 9.

[0204] The material guide portion 13 comprises at least one oxidation gas muzzle device 17 adapted for injecting an oxygen containing oxidation gas 19 into the agglomerate bed for oxidizing un-oxidized iron oxide containing material of the agglomerate bed moving along the material guide portion 13 and additionally for oxidizing un-oxidized iron oxide containing material of the agglomerate bed fed through the pre-heating device 5. The oxidation gas muzzle device 17 may comprise a plurality of through holes 21 extending through the material guide portion 13, which holes are coupled to an oxygen supply source 33. A fluid pump arrangement 35 of a gas line 37 is coupled to the oxidation gas muzzle 17 and is configured to propel the oxygen containing oxidation gas 19 through the agglomerate bed sliding along the material guide portion 13. The fluid pump arrangement 35 is electronically coupled to the control circuitry 50 for controlling the production of oxidized iron containing agglomerates.

[0205] A gas pump (not shown) is configured to propel a process gas (not shown) in counter-direction to the agglomerate bed sliding along the guide portion 13. The flow of the process gas brings the injected oxygen containing oxidation gas 19 in counterdirection to the motion of the agglomerate bed sliding along the material guide portion 13 and the injected oxygen containing oxidation gas 19 is fed in counterdirection to a pre-heating interior PH of the pre-heating device 5 and further downdraft through the agglomerate bed in the pre-heating interior PH.

[0206] An uppermost through hole 22 is arranged in an upper portion of the material guide portion 13 and is of larger diameter than the other through holes 21 further down. This promotes that a part of the oxygen containing oxidation gas 19 is guaranteed to reach the pre-heating interior PH for oxidizing un-oxidized iron oxide containing material in the pre-heating interior PH of the pre-heating device 5.

[0207] The oxidation gas muzzle device 17 thus comprises a first 21 and a second 22 oxygen containing oxidation gas injection muzzle or an uppermost through hole. The uppermost through hole 22 (oxygen containing oxidation gas injection device) is configured to inject a larger quantity of oxygen through the upper portion of the guide portion 13 next to the pre-heating device 5 relatively the oxygen quantity injected further below through the guide portion 13.

[0208] Fig. 10b shows a part of a grate-kiln pelletizing apparatus 1 configured for production of oxidized iron containing agglomerates (not shown). The grate-kiln pelletizing apparatus 1 comprises a control circuitry 50 set to control the production of oxidized iron containing agglomerates. A material guide portion 13 (such as a chute) is configured to guide an agglomerate bed (not shown), comprising iron oxide containing material not yet oxidized but subject to be oxidized and / or oxidized iron containing agglomerates, from the pre-heating device 5 to a rotary kiln (not shown). The control circuitry 50 is electronically coupled to a first fluid pump 35’ and to a second fluid pump 35”, which are provided to pump an oxygen containing oxidation gas 19 through an uppermost through hole 22 and a through hole 21 further down. The second fluid pump 35” provides larger flow of oxygen containing oxidation gas 19 from the upper portion of the material guide portion 13 than the flow of oxygen containing oxidation gas pumped by the first fluid pump 35’. The upper portion of the material guide portion 13 is positioned more near or next, relatively the lower portion of the material guide portion 13, to a pre-heating interior of a pre-heating device (not shown) configured to oxidize the iron oxide containing material comprising magnetite.

[0209] The oxidation gas muzzle device 17 thus comprises a first 21 , 35’ and a second 22, 35” oxygen containing oxidation gas injection device. The second 22, 35” oxygen containing oxidation gas injection device is configured to inject a larger quantity of oxygen through the upper portion of the guide portion 13 next to the pre-heating device 5 relatively the oxygen quantity injected further below through the guide portion 13.

[0210] The guide portion may comprise at least one oxidation gas muzzle device adapted for injecting an oxygen containing oxidation gas, such as air, into the agglomerate bed for oxidizing magnetite of the iron oxide containing agglomerates of the agglomerate bed moving along the guide portion.

[0211] 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 method of production of oxidized iron containing agglomerates (3), by means of a grate-kiln pelletizing apparatus (1), which comprises;-a pre-heating device (5) adapted to oxidize iron oxide containing agglomerates (7) comprising magnetite;-a rotary kiln device (9) adapted to sinter the oxidized iron containing agglomerates;-an agglomerate transfer member (11) coupled between the pre-heating device (5) and the rotary kiln device (9);-the agglomerate transfer member (11 ) comprises a guide portion (13) configured to guide an agglomerate bed (15), comprising oxidized iron containing agglomerates (3) and iron oxide containing agglomerates (7) comprising magnetite to be oxidized into hematite, from the pre-heating device(5) to the rotary kiln device (9); and-the guide portion (13) comprises at least one oxidation gas muzzle device (17) adapted for injecting an oxygen containing oxidation gas (19) into the agglomerate bed (15) for oxidizing magnetite of the iron oxide containing agglomerates of the agglomerate bed (15) moving along the guide portion (13); the method is characterized by the steps of:-moving the agglomerate bed (15) toward the agglomerate transfer member (11 );-oxidizing the magnetite of the iron oxide containing material (7) by introducing a process gas (43) into the agglomerate bed (15);-guiding the agglomerate bed (15) along the guide portion (13);-injecting the oxygen containing oxidation gas (19) by means of the at least one oxidation gas muzzle device (17) for oxidizing magnetite of the iron oxide containing agglomerates moving along the guide portion (13);-charging the oxidized iron containing agglomerates (3) into the rotary kiln device (9);-sintering the oxidized iron containing agglomerates (3) by means of the rotary kiln device (9); and-discharging the oxidized iron containing agglomerates (3) from the rotary kiln device (9).

2. The method according to claim 1 , wherein the method comprises the further step of:-introducing the oxygen containing oxidation gas (19) through an oxygen containing oxidation gas channel (29) of a sealing member (25) arranged between the guide portion (13) and an entrance portion (27) of the rotary kiln device (9).

3. The method according to claim 1 or 2, wherein the method comprises the further steps of:-propelling the oxygen containing oxidation gas (19) into the agglomerate bed in a first gas flow (d1 ) by means of a first fluid pump arrangement (35) of a first fluid line set-up (37);-propelling the process gas (43) in a second gas flow (d2) by means of a second fluid pump arrangement (39) of a second fluid line set-up (41 ) for bringing along the oxygen containing oxidation gas (19) in a counter-direction and / or in at least a counter-direction (d3) of the agglomerate bed (15) moving along the guide portion (13).

4. The method according to claim 3, wherein the method comprises the further step of:-providing a low pressure region (LPR) of the second fluid line set-up (41) for providing down-draft of the process gas (43) through a lower layer (45) of the agglomerate bed (15) and through a travelling grate member (47) of the preheating device (5).

5. A grate-kiln pelletizing apparatus (1) configured for production of oxidized iron containing agglomerates (3), which grate-kiln pelletizing apparatus (1 ) comprises;-a control circuitry (50) adapted to control the production of oxidized iron containing agglomerates (3);-a pre-heating device (5) adapted to oxidize an iron oxide containing material (7) comprising magnetite;-a rotary kiln device (9) adapted to sinter the oxidized iron containing agglomerates (3);-an agglomerate transfer member (11 ) coupled between the pre-heating device (5) and the rotary kiln device (9); characterized in that -the agglomerate transfer member (11 ) comprises a guide portion (13) configured to guide an agglomerate bed (15), comprising iron oxide containing material (7) to be oxidized and / or oxidized iron containing agglomerates, from the pre-heating device (5) to the rotary kiln device (9); and-the guide portion (13) comprises at least one oxidation gas muzzle device (17) adapted for injecting an oxygen containing oxidation gas (19) into the agglomerate bed (15) for oxidizing un-oxidized iron oxide containing material of the agglomerate bed (15) moving along the guide portion (13).

6. The grate-kiln pelletizing apparatus (1 ) according to claim 5, wherein the oxidation gas muzzle device (17) comprises a plurality of through holes (21 ) extending through a chute wall (23) of the guide portion (13).

7. The grate-kiln pelletizing apparatus (1 ) according to claim 5 or 6, wherein the agglomerate transfer member (11 ) comprises a sealing member (25) arranged between the guide portion (13) and an entrance portion (27) of the rotary kiln device (9); and-the sealing member (25) comprises at least one oxygen containing oxidation gas channel (29) adapted for injecting the oxygen containing oxidation gas (19) into the agglomerate bed (15) for oxidizing un-oxidized iron oxide containing material of the agglomerate bed (15) moving along the guide portion (13).

8. The grate-kiln pelletizing apparatus (1 ) according to any of claims 5 to 7, wherein the guide portion (13) slopes from a discharge portion (31 ) of the preheating device (5) toward the rotary kiln device (9).

9. The grate-kiln pelletizing apparatus (1 ) according to any of the preceding claims, wherein the oxidation gas muzzle device (17) is coupled to an oxygen supply source (33).

10. The grate-kiln pelletizing apparatus (1 ) according to any of the preceding claims, wherein the grate-kiln pelletizing apparatus (1 ) comprises;-a first fluid pump arrangement (35) of a first fluid line set-up (37) coupled to the oxidation gas muzzle device (17) and configured to propel the oxygen containing oxidation gas (19) into the agglomerate bed (15) in a first gas flow (d1 );-a second fluid pump arrangement (39) of a second fluid line set-up (41 ) configured to propel a process gas (43) in a second gas flow (d2) bringing along the oxygen containing oxidation gas (19) in a counter-direction and / or in at least a counter-direction (d3) of the agglomerate bed (15) moving along the guide portion (13).11 . The grate-kiln pelletizing apparatus (1 ) according to any of the preceding claims, wherein a lower layer (45) of the agglomerate bed (15) comprising iron oxide containing material (7) is supported by an agglomerate bed transport device (AD) of a travelling grate member (47) configured to carry the agglomerate bed and extending along and within a pre-heating interior (PH) of the pre-heating device (5).

12. The grate-kiln pelletizing apparatus (1 ) according to any of the preceding claims, wherein the control circuitry (50) is adapted to control the production of oxidized iron containing agglomerates (3) based on the method steps according to any of claims 1 to 4; wherein the control circuitry (50) is electrically coupled to;-a traveling grate driving motor arrangement (61 ) for controlling the motion of the agglomerate bed (15) through a pre-heating interior (PH) of the preheating device (5);-a first fluid pump arrangement (35) of a first fluid line set-up (37) for controlling injection of the oxygen containing oxidation gas (19) into the agglomerate bed (15) in a first gas flow (d1 ) via the oxidation gas muzzle device (17);-a second fluid pump arrangement (39) of a second fluid line set-up (41 ) for controlling the feeding of a process gas (43) in a second gas flow (d2) for bringing along the oxygen containing oxidation gas (19) in a direction opposite the moving direction of the agglomerate bed (15) moving along the guide portion (13); and-a burner device (63) of the rotary kiln device (9) adapted to provide sintering of the oxidized iron containing agglomerates (3).

13. The grate-kiln pelletizing apparatus (1) according to claim 12, wherein the control circuitry (50) is electrically coupled to;-a process gas heating device (65) configured to heat the process gas (43) to be down-drafted through the agglomerate bed (15) for providing the oxidizing of the iron oxide containing material (7) by means of the pre-heating device (5).

14. The grate-kiln pelletizing apparatus (1 ) according to claim 12 or 13, wherein the control circuitry (50) is electrically coupled to;-a third fluid pump arrangement (67) of a third fluid line set-up (69) for controlling the feeding of the process gas (43) into the rotary kiln device (9) in a direction opposite the moving direction of the agglomerate bed (15) moving through the rotary kiln device (9); and-the second fluid pump arrangement (39) for controlling the flow rate of the process gas (43) for bringing along the oxygen containing oxidation gas (19) in a counter-direction and / or in at least a counter-direction (d3) of the agglomerate bed (15) moving along the guide portion (13).

15. A data program (P), programmed for causing the grate-kiln pelletizing apparatus (1 ) according to any of claims 5 to 14 to execute the method according to any of claims 1 to 4, wherein said data program (P) comprises aprogram code readable on a computer of the control circuitry (50) for causing the grate-kiln pelletizing apparatus (1 ) to execute the method steps according to any of claims 1 to 4.

16. The grate-kiln pelletizing apparatus (1) according to any of claims 5 to 14, wherein the oxidation gas muzzle device (17) comprises a first (21 , 35’) and a second (22, 35”) oxygen containing oxidation gas injection device, the second (22, 35”) oxygen containing oxidation gas injection device is configured to inject a larger quantity of oxygen through an upper portion of the guide portion (13) next to the pre-heating device (5) than that injected further down through the guide portion (13).

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