SOLID CARBONIZED AGGLOMERATE, AND ITS MANUFACTURING METHOD

Abstract

A carbonized solid agglomerate for use in a blast furnace, comprising in its composition: at least one source of carbon (10); at least one source of calcium (11); and at least one binder (12); wherein, after mechanical shaping (200) of the solid agglomerate, the agglomerate is subjected to a pyrolyzing step (400) at a temperature greater than or equal to 600 C. and less than 800 C.; wherein the solid agglomerate comprises 25 to 35% by mass of the at least one source of calcium (11). A method for manufacturing the proposed solid agglomerate.

Claims

1. A solid carbonized agglomerate for use in blast furnaces, the solid carbonized agglomerate comprising: at least one source of carbon (10); at least one source of calcium (11); and at least one binder (12), wherein after the mechanical shaping (200) of the solid agglomerate, the solid agglomerate is subjected to a pyrolyzing step (400) at a temperature greater than or equal to 600 C. and less than 800 C., and wherein the solid agglomerate comprises 25 to 35% by mass of at least one source of calcium (11).

2. The solid agglomerate according to claim 1, wherein the at least one source of carbon (10) is selected from the group consisting of: biocarbon, coal and metallurgical coal.

3. The solid agglomerate according to claim 1, wherein the at least one source of calcium (11) is a source of calcium oxide selected from the group consisting of: limestone and calcium-containing steel waste.

4. The solid agglomerate according to claim 1, wherein the at least one binder (12) is an organic binder.

5. The solid agglomerate according to claim 1, comprising 60 to 90% by mass of the at least one source of carbon (10).

6. The solid agglomerate according to claim 5, wherein the at least one source of carbon (10) comprises up to 70% by mass of biocarbon and between 30 and 100% by mass of coal.

7. The solid agglomerate according to claim 1, comprising 5 to 10% by mass of the at least one binder (12).

8. The solid agglomerate according to claim 1, further comprising 5 to 15% by mass of an iron-based compound.

9. The solid agglomerate according to claim 8, wherein the iron-based compound is iron oxide or metallic iron.

10. A method of manufacturing a solid carbonized agglomerate for use in a blast furnace, the method comprising: mixing (100) at least one source of carbon (10), at least one source of calcium (11) and at least one binder (12); mechanically shaping (200) a mixture of the at least one source of carbon (10), the at least one source of calcium (11) and the at least one binder (12) to form a solid shaped agglomerate (20); and pyrolyzing (400) the solid shaped agglomerate (20) at a temperature greater than or equal to 600 C. and less than 800 C.; wherein the solid shaped agglomerate comprises 25 to 35% by mass of at least one source of calcium (11).

11. The method according to claim 10, further comprising mixing 60 to 90% by mass of the at least one source of carbon (10), wherein the at least one source of carbon (10) is selected from the group consisting of: biocarbon, coal and/or metallurgical coal.

12. The method according to claim 11, comprising forming the at least one source of carbon (10) with up to 70% by mass of biocarbon and between 30 and 100% by mass of coal.

13. The method according to claim 10, wherein the step of mixing (100) comprises mixing 5 to 10% by mass of the at least one binder.

14. The method according to claim 10, wherein the step of mixing (100) comprises mixing 5 to 15% by mass of an iron-based compound.

15. The method according to claim 14, wherein the iron-based compound is iron oxide or metallic iron.

16. The method according to claim 10, further comprising, after the mechanical shaping step (200), drying (300) the shaped agglomerate (20) in an oven at 105 C. for two hours with the humidity inside the oven being less than 1%.

Description

BRIEF DESCRIPTION OF THE FIGURE

[0022] The detailed description below refers to the attached figures and their respective reference numbers.

[0023] FIG. 1 illustrates a flowchart of the method of manufacturing a solid carbonized agglomerate according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0024] First of all, it should be noted that the following description will be based on a preferred embodiment of the invention. As will be evident to anyone skilled in the art, however, the invention is not limited to this particular embodiment.

[0025] The present invention provides a method of manufacturing a solid carbonized agglomerate for use in a blast furnace, characterized by the fact that it comprises the steps of: mixing 100 at least one source of carbon 10, at least one source of calcium 11 and at least one binder 12; mechanically 200 the mixture of the at least one source of carbon 10, the at least one source of calcium 11 and the at least one binder 12 so as to form a shaped solid agglomerate 20; and pyrolyzing 400 the shaped solid agglomerate 20 at a temperature of greater than or equal to 600 C. and less than 800 C.; wherein the solid agglomerate comprises 25 to 35% by mass of the at least one source of calcium 11.

[0026] It should be noted that this certificate of incorporation refers to an improvement of a solid carbonized agglomerate and the process for manufacturing it as described in BR102022023262-8, which will be explained below for a better understanding of the invention.

Solid Agglomerate Coked at Low Temperatures

[0027] A coked solid agglomerate for use in a steel furnace is described, comprising biocarbon, mineral coal and at least one binder. For the purposes of this description, biocarbon means any charcoal of plant origin produced according to substantially sustainable standards. Preferably, this biocarbon has a low inorganic content (less than 1%).

[0028] Once submitted to mechanical shaping, the solid agglomerate undergoes a pyrolysis process at a temperature greater than or equal to 700 C. and less than 800 C. This heat treatment cokes the carbonaceous material in the mixture and increases the interaction and anchoring between all the components of the solid agglomerate, improving its mechanical strength. In addition, the pyrolysis of the solid agglomerate promotes its drying and pre-reduction, increasing its calorific value and preparing it for use in steel furnaces.

[0029] Preferably, the pyrolysis of the solid agglomerate is carried out in a rotating cylindrical reactor.

[0030] Preferably, the solid agglomerate comprises 10 to 75% by mass of biocarbon. More preferably, the solid agglomerate comprises 50 to 65% by mass of biocarbon.

[0031] Preferably, the solid agglomerate comprises 25 to 90% by mass of coal. More preferably, the solid agglomerate comprises 25 to 50% by mass of coal.

[0032] Preferably, the solid agglomerate contains 5 to 10% by mass of a binder, which has the function of keeping the compounds in the solid agglomerate bound together. The use of a binder also allows for the use of smaller-grained compounds in the composition of the solid agglomerate.

[0033] Optionally, the solid agglomerate also contains 5 to 15% by mass of an iron-based compound, such as iron oxide or metallic iron. The source of iron used is preferably steelmaking waste, such as sludge from steelmaking processes. Mixing an iron-based compound with the agglomerate produces an iron-containing agglomerate. As is well known, due to the catalytic effect of the iron content of the iron-containing agglomerate, the reaction of the carbonaceous material starts from a lower temperature compared to conventional coke and, as a result, a reduction effect can be expected and, as a result, one can expect a reducing effect on the reducing agent ratio (RAR) by lowering the temperature of the thermal reserve zone when iron-containing agglomerate is used as a charge material in the steel furnace.

[0034] A process for manufacturing a solid coked agglomerate for use in a steelmaking furnace is also described, comprising the steps of (i) mixing biocarbon, coal and at least one binder, (ii) mechanically shaping the mixture of biocarbon, coal and at least one binder to form a solid agglomerate, and (iii) pyrolyzing the solid agglomerate at a temperature greater than or equal to 700 C. and less than 800 C.

[0035] Preferably, the mixing stage is carried out with 10 to 75% by mass of biocarbon. More preferably, the mixing stage is carried out with 50 to 65% by mass of biocarbon.

[0036] Preferably, the mixing stage is carried out with 25 to 90% by mass of coal. More preferably, the mixing stage is carried out with 25 to 50% by mass of coal.

[0037] Preferably, the mixing stage is carried out with 5 to 10% by mass of a binder.

[0038] Optionally, the mixing step additionally involves mixing 5 to 15% by mass of an iron-based compound such as iron oxide or metallic iron to form an iron-containing agglomerate.

[0039] It should be noted that, due to temperatures lower than 800 C., solid agglomerate and the process of making it have considerable energy savings in the manufacturing process.

[0040] Coked solid agglomerate can be used in blast furnaces and sintering ovens. Solid agglomerate containing iron can be used to replace small coke in blast furnaces.

Solid Carbonized Agglomerate With Source of Calcium

[0041] FIG. 1 illustrates a flowchart of the manufacturing method for solid carbonized agglomerate. Preferably, the manufacturing method comprises mixing 100 at least one source of carbon 10, at least one source of calcium 11 and at least one binder 12, mechanically shaping 200 the mixture using rotating rollers to form a briquette-shaped agglomerate 20, and pyrolyzing 400 the shaped agglomerate 20 at a temperature of between 600 C. and 800 C. so that the material is carbonized.

[0042] Optionally, after the mechanical shaping step 200, the method of the present invention comprises drying 300 the shaped agglomerate 20 in an oven at 105 C. for two hours with the humidity inside the oven being less than 1%.

[0043] Preferably, the step of pyrolyzing 400 the shaped agglomerate 20 is carried out in a cylindrical rotary reactor. This heat treatment causes the carbonaceous material in the mixture to be carbonized and increases the interaction and anchoring between all the components of the solid agglomerate, improving its mechanical strength. In addition, the pyrolysis of the solid agglomerate promotes its drying and pre-reduction, increasing its calorific value and preparing it for use in blast furnaces.

[0044] Preferably, at least one source of carbon 10 is at least one of the following: biocarbon, coal and/or metallurgical coal. For the purposes of this description, biocarbon means any charcoal of plant origin produced according to substantially sustainable standards. Preferably, this biocarbon has a low inorganic content (less than 1%).

[0045] Preferably, at least one source of calcium 11 is a source of calcium oxide from at least one of the following: primary sources of calcium (limestone) or calcium-containing steel waste.

[0046] Preferably, at least one binder 12 is an organic binder, such as starch.

[0047] Preferably, the mixing step 100 is carried out with 60 to 90% by mass of source of carbon 10. More preferably, the step of mixing 100 is carried out with 60 to 80% by mass of source of carbon 10. Preferably, source of carbon 10 is formed with up to 70% by mass of biocarbon and between 30 and 100% by mass of coal.

[0048] Preferably, the mixing step 100 is carried out with 0 to 10% by mass of at least one binder 12. More preferably, the mixing step 100 is carried out with 5 to 10% by mass of at least one binder 12.

[0049] Preferably, the step of mixing 100 comprises mixing 10 to 40% by mass of at least one source of calcium 12. More preferably, the step of mixing 100 comprises mixing 25 to 35% by mass of at least one source of calcium 12. More preferably, the step of mixing 100 comprises mixing 27 to 32% by mass of at least one source of calcium 12.

[0050] The present invention additionally provides a carbonized solid agglomerate for use in a blast furnace, comprising in its composition: at least one source of carbon 10; at least one source of calcium 11; and at least one binder 12; wherein, after mechanical shaping 200 of the solid agglomerate, the solid agglomerate is subjected to a pyrolyzing step 400 at a temperature greater than or equal to 600 C. and less than 800 C.; wherein the solid agglomerate comprises 25 to 35% by mass of at least one source of calcium 11.

[0051] Once it has undergone mechanical shaping, the shaped agglomerate 20 goes through a pyrolysis stage 400 at a temperature preferably between 600 C. and 800 C. More preferably, the pyrolyzing step 400 is carried out at a temperature greater than or equal to 600 C. and less than 700 C. Optionally, the pyrolyzing step 400 is carried out at a temperature greater than or equal to 700 C. and less than 800 C.

[0052] Optionally, before pyrolyzing 400 the agglomerate, the shaped agglomerate 20 is dried 300 in an oven at 105 C. for two hours with the humidity inside the oven being less than 1%.

[0053] Preferably, at least one source of carbon 10 is at least one of the following: biocarbon, coal and/or metallurgical coal.

[0054] Preferably, at least one source of calcium 11 is a source of calcium oxide from at least one of the following: calcitic limestone, dolomitic limestone, hydrated lime and/or quicklime.

[0055] Preferably, at least one binder 12 is an organic binder, such as starch.

[0056] Preferably, the solid agglomerate of the present invention comprises from 60 to 90% by mass of source of calcium, where the source of carbon 10 comprises up to 70% by mass of biocarbon and between 30 and 100% by mass of coal. More preferably, the solid agglomerate comprises 60 to 80% by mass of source of calcium, where the source of carbon 10 comprises up to 70% by mass of biocarbon and between 30 and 100% by mass of coal.

[0057] Preferably, the solid agglomerate of the present invention comprises from 0 to 10% by mass of at least one binder 12. More preferably, the solid agglomerate of the present invention comprises from 5 to 10% by mass of at least one binder 12. The binder 12 has the function of keeping the compounds in the solid agglomerate bound together. The use of a binder 12 also allows the use of compounds with a smaller grain size in the composition of the solid agglomerate.

[0058] Preferably, the solid agglomerate of the present invention comprises from 10 to 40% by mass of at least one source of calcium 12. More preferably, the solid agglomerate comprises 25 to 35% by mass of at least one source of calcium. More preferably, the step of mixing 100 comprises mixing 27 to 32% by mass of at least one source of calcium 12.

[0059] The source of calcium 12 used is preferably steel waste, such as sludge from steelmaking processes. Due to the catalytic effect of the calcium content of the calcium-containing agglomerate, the reaction of the carbonaceous material starts from a lower temperature compared to conventional coke and, as a result, a reduction effect can be expected and, as a result, one can expect a reducing effect on the reducing agent ratio (RAR) by lowering the temperature of the thermal reserve zone when the calcium-containing agglomerate is used as a charge material in the steel furnace.

[0060] Preferably, the solid agglomerate of the present invention is a catalyzed briquette for blast furnaces.

[0061] Thus, the solid carbonized agglomerate and the method of manufacturing the solid carbonized agglomerate according to the present invention are attractive because they allow the blast furnace to increase its efficiency in reducing iron oxides, thus optimizing fuel consumption and consequently reducing CO.sub.2 emissions.

[0062] In addition, the use of calcium oxide sources instead of iron oxide sources in the agglomerate provides the following advantages: (1) obtaining a more resistant briquette, since part of the physical degradation of briquettes with iron oxide is the consumption of structural carbon for reduction at high temperatures during the carbonization process, (2) calcium oxide is more effective in catalytic capacity compared to iron (metallic or as wstite), (3) in the steel industry, a lot of waste comprising calcium is generated, which makes this material abundant for use in the agglomerate of the present invention, allowing the reuse of this waste, decreasing the environmental impact of disposing it, (4) briquettes containing calcium oxide can be carbonized in a conventional coke oven, since the iron oxide reacts with the silicon oxide present in the refractory of the coke oven and forms low melting point phases that corrode the refractory, (5) they are more interesting for low-temperature carbonization processes, since the oxide source (CaO) is already the catalytic phase, with no need for prior reduction.

[0063] It should also be noted that calcium oxide (CaO) is a catalyst in the Boudouard reaction (gasification reaction), while in the case of iron oxide, the catalyst is metallic iron (mainly). In other words, in order to have catalysis with a cluster comprising iron, it is necessary to reach high temperatures and cause reduction. With calcium produced at low temperature, the catalytic phase is already present.

[0064] It should also be noted that the present invention does not exclude the use of mixed materials to form the solid agglomerate, such as waste rich in CaO and iron oxides in its composition. This form of the invention, with a solid carbonized agglomerate comprising at least one source of calcium 12 and at least one source of iron, is advantageous in that it reuses steel mill waste containing these materials, which could previously have been discarded and caused environmental damage. In addition, this agglomerate combines the catalytic effects of iron and calcium, making it more calorific.

[0065] Optionally, the solid carbonized agglomerate of the present invention additionally comprises 5 to 15% by mass of an iron-based compound, such as iron oxide or metallic iron.

[0066] Optionally, the mixing step 100 of the method for manufacturing a solid carbonized agglomerate comprises mixing 5 to 15% by mass of an iron-based compound, such as iron oxide or metallic iron.

[0067] Previously, it was seen that the solid agglomerate of BR102022023262-8 could be pyrolyzed at temperatures below 800 C., specifically between 700 C. and 800 C. However, with the introduction of the source of calcium 11 into the agglomerate, it was found that the pyrolyzing step could be carried out at even lower temperatures, specifically between 600 C. and 700 C., in addition to the previous range of 700 C. and 800 C., which requires less energy to manufacture and provides the advantages highlighted above, with better catalytic properties than the BR102022023262-8 agglomerate.

[0068] Numerous variations affecting the scope of protection of this request are permitted. This reinforces the fact that the present invention is not limited to the particular configurations/concretizations described above.