Method for producing a solid composite material

Abstract

The present disclosure provides a method of producing a solid composite material. The method includes providing a bio-roughage formed from a thermal treatment of a carbon-containing feedstock including biomass. The bio-roughage is capable of hardening at an elevated temperature. The method further includes mixing the bio-roughage with a solid or a paste to form a rough composite material, and heating the rough composite material to produce a hardened solid composite material.

Description

Technical Field

[0001] This invention relates to a method for producing solid composite materials, particularly composite materials containing minerals. Background Technology

[0002] Many industrial processes are both energy-intensive and carbon-intensive. Examples of such processes include the production of iron and steel from iron ore and the production of silicon from silica. Fossil fuels, such as coal, are typically the primary source of energy and carbon. For instance, metallurgical coke, produced from high-quality bituminous coal, is the primary form of carbon used in the steel industry, particularly as feedstock for blast furnaces. These industrial sectors are major sources of greenhouse gases, especially CO2, and are actively seeking alternative and low-emission ways to supply the energy and carbon required for their processes.

[0003] While many renewable energy sources can be used to meet the energy requirements of these industrial processes in order to reduce their CO2 emissions, biomass is the only renewable energy source that can be directly used to meet the carbon requirements of these industrial processes.

[0004] Mineral processing is a process commonly used to improve the quality (purity) of raw minerals such as iron ore. It typically involves crushing, thus producing fine mineral particles. These fine particles must then be formed into larger pellets, for example, through granulation or briquetting, so that the fine particles become feedstock in the form of small balls and lumps, suitable for the desired process, such as as feedstock for a blast furnace. Clay, such as bentonite, is commonly used as a binder. However, such inorganic binders can easily introduce undesirable inorganic impurities into the process, which can adversely affect the main process and ultimately be discharged from the process as slag requiring treatment. Organic binders are desirable, especially if they can also interact physically and / or chemically with the minerals to be processed to form composites and become part of the carbon required in the process. Chemical reactions between the binder and the minerals will be advantageous in producing composites with high mechanical strength.

[0005] While carbon can also be used as an energy source, the "carbon" required by the aforementioned industrial sectors is typically a reactant, such as a reducing agent, to reduce iron ore to iron or silica to silicon. As used herein, "carbon" does not necessarily refer to pure carbon, but primarily to carbon-rich carbonaceous materials. Metallurgical coke and activated carbon are typical examples of these "carbon" materials. Close contact between the carbonaceous material and the mineral to be reacted (reduced) in composite materials will have many beneficial effects on process acceleration and improved process efficiency.

[0006] During the production of carbon materials and / or during subsequent carbon material preparation, numerous fines are produced so that carbon materials with required particle size ranges can be fed into desired industrial processes, such as blast furnaces or electric arc furnaces. For example, numerous metallurgical coke fines are produced when metallurgical coke is crushed to produce and feed coke with required particle size ranges into blast furnaces. These coke fines cannot be fed directly into blast furnaces and have a lower commercial value than coke lumps. Another example is the production and preparation of biochar as feedstock for silicon production in electric arc furnaces, resulting in biochar fines. Again, biochar fines cannot be fed into electric arc furnaces and have a lower commercial value than biochar lumps. Producing block carbon materials using the appropriate fines would be a significant commercial outcome. Specifically, the block carbon materials produced from the fines should meet the quality requirements of the intended use; for example, coke lumps should have sufficient mechanical strength required for blast furnaces producing iron and steel, or biochar lumps should have sufficient mechanical strength required for electric arc furnaces producing silicon.

[0007] The scope of this invention should in no way be limited to the examples cited above. Other examples in which the fine material is made into large particles may be cited, since large particles have a higher commercial value than fine material.

[0008] Biomass can be thermally treated at elevated temperatures to produce biomass roughage, which can then be used as a binder or a component of binders. A typical type of biomass roughage is bio-oil derived from the pyrolysis of biomass (which also produces a solid byproduct called biochar). Upon heating, bio-oil devolatiles and hardens. Bio-oil contains abundant reactive structures and functional groups that can react with minerals to form very strong bonds between the minerals and the components derived from the biomass roughage. Hydrothermal liquefaction of biomass can also produce reactive biomass roughage. Biomass roughage can also serve as a binder for other materials, such as metallurgical coke fines and / or biochar fines.

[0009] Organic binders can decompose at high temperatures, releasing flammable volatiles. The use of carbon as a reducing agent can also produce gases, such as CO, which has a useful calorific value. The recovery of the energy value of these volatiles and gases is important for overall process energy efficiency.

[0010] The carbon in organic binders can also become part of the carbon needed in processes that upgrade minerals, for example, as a reducing agent in blast furnaces or similar processes to reduce iron ore to iron.

[0011] Therefore, there is a need to develop organic binders from biomass and / or to bring carbon from the ore (or other materials to be bonded) in close contact with the composite material into high-temperature processes, for example, for reducing iron ore to iron. Summary of the Invention

[0012] According to a first aspect of the present invention, a method for producing a solid composite material is provided, the method comprising:

[0013] Provides biomass crude material formed by heat treatment of carbonaceous feedstock including biomass, which can harden at elevated temperatures;

[0014] Biomass coarse materials are mixed with solids or pastes to form coarse composite materials; and

[0015] Heating the rough composite material produces a hardened solid composite material.

[0016] The embodiments of the present invention have significant advantages. In particular, the resulting solid composite material can have relatively high density and strength. Furthermore, the resulting solid composite material can have relatively low sulfur content, and the biomass feedstock does not introduce undesirable impurities into the composite material. Additionally, the biomass feedstock can contain useful substances that can, for example, act as fluxes in subsequent steelmaking processes.

[0017] As used herein, the term "biomass" refers to any material derived from living or recently living organisms. While biomass is a preferred feedstock for producing organic binders due to its potential carbon neutrality and other properties, other carbon-containing feedstocks may also be used, including a variety of renewable and non-renewable carbon-containing feedstocks, including but not limited to coal, solid waste, or mixtures thereof. Solid waste may include, but is not limited to, agricultural waste, forestry waste, and domestic / municipal solid waste or residues from the processing of carbon-containing feedstocks. In fact, broadly speaking, many solid wastes are considered biomass. Alternatively, biomass may be a significant component of at least many solid wastes.

[0018] As used herein, the term "heat treatment" is intended to encompass, within its scope, any process carried out at elevated temperatures, with or without the presence of other substances. For example, the pyrolysis of biomass in an inert, oxidizing, or reducing atmosphere is a heat treatment process. Hydrothermal treatment of biomass in subcritical, critical, or supercritical water is another heat treatment process.

[0019] As used herein, the term "bio-raw material" is intended to include any liquid or paste-like product from the thermal treatment of biomass or other carbon-containing feedstocks. Bio-oil from the pyrolysis of biomass is a typical example of bio-raw material.

[0020] As used herein, the term “biochar” (or “char”) is intended to include solid products from the thermal treatment of biomass or other carbon-containing feedstocks.

[0021] As used herein, the term "composite material" is intended to encompass, within its scope, any material composed of two or more component materials having different properties. "Rough composite material" refers to a mixture of precursors used to produce the final solid composite material. Rough composite materials can be in the shape of spheres and clumps or any other regular or irregular shape and can be of any size.

[0022] The methods of this invention can be carried out in a wide range of relative proportions between bio-based feedstocks and solids to produce solid composite materials with a wide variety of compositions and properties.

[0023] In this implementation, the solid includes minerals such as iron ore or silica. For example, the solid could be magnetite iron ore.

[0024] In another embodiment, the solid includes solid carbon materials. For example, the solid may be metallurgical coke, biochar, or char.

[0025] In one embodiment, the solid can have a wide range of particle sizes. For example, finely selected magnetite ore or magnetite ore blocks can be mixed with bio-oil to produce a crude composite material. The solid may contain impurities, including but not limited to water.

[0026] In a further embodiment, the solid may be in the form of a slurry containing water or other chemicals.

[0027] In this embodiment, the solid includes mixed solids. For example, the solid may be a mixture of magnetite and hematite iron ore with other impurities. Alternatively, the solid may be a mixture of ore and biochar or a mixture of ore and metallurgical coke.

[0028] In a further embodiment, the crude composite material may include a flux, such as lime, to facilitate subsequent processing of the composite material.

[0029] In a further embodiment, the crude composite material may include additional chemicals, including catalysts, to accelerate the hardening of the composite material.

[0030] The step of heating the rough composite material can be carried out by heating the rough composite material to a temperature between 100°C and 600°C, preferably between 150°C and 450°C, and still more preferably between 200°C and 350°C. The heating can be carried out in an inert atmosphere, a reducing atmosphere, or an oxidizing atmosphere.

[0031] In another embodiment, the step of heating the crude composite material can be carried out by heating the crude composite material to a temperature above 600°C in an inert atmosphere, a reducing atmosphere, or an oxidizing atmosphere.

[0032] In this implementation, the step of heating the rough composite material is performed in a stepwise manner. For example, the temperature can be gradually increased at different heating rates, and different times can be maintained at the selected temperature levels.

[0033] The method may include further steps of carbonizing the composite material at high temperatures, preferably above 600°C, more preferably above 800°C, and still more preferably above 1000°C, particularly but not limited to carbonizing the carbon-containing component derived from biomass in the composite material.

[0034] The method may include a further step of burning the composite material by reacting it with an oxidant, such as air, so that the solids in the composite material are at least partially melted or recrystallized to achieve better mechanical strength.

[0035] According to a second aspect of the present invention, a method for producing a solid composite material is provided, the method comprising:

[0036] Provides biomass crude material formed by heat treatment of carbonaceous feedstock including biomass, which can harden at elevated temperatures;

[0037] Provide biochar formed from carbonaceous feedstock, including biomass, through heat treatment;

[0038] Biomass coarse material and biochar are mixed with solids or pastes to form a crude composite material; and

[0039] Heating the rough composite material produces a hardened solid composite material.

[0040] Including biochar in crude composites can advantageously increase the carbon content of the composites. Biochar and crude biochar can be produced by heat treatment of the same or different carbon-containing feedstocks.

[0041] According to a third aspect of the present invention, a method for producing a solid composite material is provided, the method comprising:

[0042] Provides biomass crude material formed by heat treatment of carbonaceous feedstock including biomass, which can harden at elevated temperatures;

[0043] Biomass coarse material is mixed with solids or pastes to form a coarse composite material;

[0044] Heating the coarse composite material to produce a hardened solid composite material; and

[0045] Recover the volatiles released by heating the crude composite material.

[0046] According to a fourth aspect of the present invention, a method for producing a solid composite material is provided, the method comprising:

[0047] Provides biomass crude material formed by heat treatment of carbonaceous feedstock including biomass, which can harden at elevated temperatures;

[0048] Provide biochar formed from carbonaceous feedstock, including biomass, through heat treatment;

[0049] Biomass and biochar are mixed with solids or pastes to form a crude composite material;

[0050] Heating the coarse composite material to produce a hardened solid composite material; and

[0051] Recover the volatiles released by heating the crude composite material.

[0052] Biochar and biomass can be produced by heat treatment of the same or different carbon-containing feedstocks.

[0053] In an embodiment of the third or fourth aspect of the invention, the step of recovering volatiles includes feeding the volatiles into a combustion device to provide thermal energy to heat the crude composite material.

[0054] In a further embodiment of the third or fourth aspect of the invention, the step of recovering the volatiles includes cooling the volatiles to form a mixture of liquid and non-condensable gas. The liquid or non-condensable gas mixture can be used alone or together as fuel to supply thermal energy required for heating the crude composite material or for other purposes.

[0055] In a specific embodiment of the third or fourth aspect of the invention, the recovered volatiles are used as fuel for power generation. Any suitable power generation method known now or in the future, such as the use of an internal combustion engine or a gas turbine, can be used for this purpose. Attached Figure Description

[0056] Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings:

[0057] Figure 1 A flowchart of a method for generating a solid composite material according to an embodiment of the present invention; Detailed Implementation

[0058] Embodiments of the present invention relate to a method for producing solid composite materials. To produce the solid composite material, a biomass rough formed by thermal treatment of biomass or other carbon-containing feedstocks or mixtures thereof is provided, wherein the biomass rough is capable of hardening upon heating. Without necessarily following any particular theory, the hardening process involves complex chemical reactions involving reactive substances and functional groups in the biomass rough, in addition to the evaporation of water and light matter from the biomass rough, and solids involved in forming part of the crude composite material. The description of embodiments herein focuses on bio-oil from the pyrolysis of biomass; however, the biomass rough in the present invention is not limited to bio-oil alone. Various biomass pyrolysis techniques known now or to be invented in the future can be used to produce bio-oil. For example, milling pyrolysis (PCT / AU2011 / 000741) is very efficient in producing bio-oil for producing composite materials using the method of the present invention. Pyrolysis processes typically also produce solid byproduct biochar and gaseous byproducts including non-condensable gases. Biochar can also be used as a feedstock for producing solid composite materials in the present invention.

[0059] Bio-oils are mostly liquids, but those skilled in the art will recognize that they can contain colloids and even solids (including biochar). Besides water, bio-oils can contain many organic compounds with various chemical functional groups, especially oxygen-containing functional groups. Bio-oils may also contain dissolved inorganic substances and inorganic solids, such as sodium, potassium, magnesium, and calcium salts. These can have beneficial effects on subsequent processes using composite materials as feedstocks. For example, in the steel industry, they can act as fluxes in blast furnaces. In some pyrolysis processes, bio-oils are produced in the form of pastes or slurries. In some pyrolysis processes, slurries that directly produce bio-oil and biochar are produced.

[0060] Bio-oil is mixed with solids to produce a crude composite material. In one embodiment, bio-oil is mixed with magnetite ore to produce a crude composite material comprising bio-oil and magnetite. In another embodiment, bio-oil and biochar are mixed with magnetite ore to produce a crude composite material. In a further embodiment, various additional chemical substances are also added to the mixture to produce a crude composite material with different properties.

[0061] In a further embodiment, the bio-oil is mixed with a carbonaceous material to produce a crude composite material. The carbonaceous material may be metallurgical coke or biochar or any solid derived from the heat treatment of a carbon-containing feedstock. Additional chemicals, including catalysts, may also be components of the crude composite material.

[0062] The mixing process can be carried out in various ways, and crude composite materials can be produced in various shapes. Bio-oil and solids can be extruded into crude composite materials with the desired shape. In one embodiment, a granulation disc is used to mix and roll bio-oil and iron ore, which may also include biochar or any other chemical components as described above, into clumps. In a further embodiment, a granulation drum is used.

[0063] The relative proportions of bio-oil, iron ore, and other components, including biochar and other chemicals, in the composite material can be varied over a wide range to suit the needs of subsequent processes using the composite material.

[0064] The crude composite material is then heated to produce the final solid composite product. Heating can be carried out in various ways, such as in an inert, reducing, or oxidizing atmosphere, to harden the composite material.

[0065] During heating, numerous physical processes and chemical reactions can occur. Moisture, such as that found in bio-oil or iron ore, will evaporate. Some of the lighter components in bio-oil will also evaporate. Depending on the temperature, the reactive functional groups in the bio-oil will also undergo various reactions, particularly cracking and polymerization, to produce additional lighter and heavier components. The heavier components are particularly important for binding solid particles (such as ore) together.

[0066] Without following any particular theory, components in bio-oils can also react with solids (such as iron ore, biochar, or other carbon materials) to form new chemical bonds between the bio-oil components and the iron ore. These types of chemical bonds will be much stronger than physical interactions / forces, greatly contributing to the mechanical strength of composite products.

[0067] The crude composite material can be heated in various ways. In one embodiment, the crude composite material is heated in an oxidizing atmosphere to cause at least some of the bio-oil components to burn. Combustion heats the crude composite material to a high temperature, causing some degree of melting / sintering of the iron ore, during which recrystallization or other physicochemical processes may occur to produce a composite material with high mechanical strength. Simultaneously, some of the iron ore may also be at least partially reduced. The combustion process can be performed on the crude composite material or on the final composite product.

[0068] In the steel industry, composites derived from bio-oil and iron ore, and / or composites derived from bio-oil and metallurgical coke, can be used as part of the feedstock for blast furnaces. Composites derived from bio-oil and solid biochar (or other types of char) can be fed into electric arc furnaces to produce silicon.

[0069] Volatile substances released by heating crude composite materials can contain many flammable components. If heating is carried out at relatively low temperatures (e.g., below about 600°C), some of these volatile components can condense to produce liquid fuels and non-condensable gaseous fuels.

[0070] Iron ore can be an excellent catalyst for converting released volatiles into lighter gases. Therefore, in a specific embodiment, the composite material produced in this invention is used for integration with a power generation process, wherein the volatiles and gases released by heating the crude composite material are used to generate electricity using a power generation device. Examples of such power generation devices include, but are not limited to, internal combustion engines, gas turbines, and fuel cells.

[0071] For reference Figure 1 A flowchart illustrating method 100 is shown according to a specific embodiment of the present invention.

[0072] In the first step 102, a biomass feedstock formed by biomass thermal treatment and capable of hardening is provided. In this specific embodiment, the biomass feedstock is bio-oil obtained from the pyrolysis of biomass.

[0073] In step 104, biochar is provided. Although bio-oil and biochar are usually produced simultaneously by the pyrolysis of the same biomass, they can also be produced from different biomass and using different heat treatment processes.

[0074] Specific examples of the pyrolysis process are described in more detail in PCT International Patent Application No. PCT / AU2011 / 000741.

[0075] In the next step 106, the bio-oil and biochar are mixed with a solid to form a crude composite material. In this particular embodiment, the solid is magnetite ore, especially fine magnetite ore after beneficiation. Instead of biochar and iron ore, the solid may also be fine biochar produced during the generation and preparation of biochar for silicon production processes. In a further embodiment, silica may be added to form the crude composite material so that the silica in the final composite product is in close contact with carbon to facilitate its reduction to form silicon in an electric arc furnace. Mixing can be carried out at room temperature. In this specific example, mixing is performed to form a desired shape. The crude composite material can be formed by extrusion.

[0076] The crude composite material is then heated in step 108 to a temperature at which the bio-oil hardens through complex physical and chemical processes. The bond between the carbon-containing components (including reaction products from the bio-oil) and the magnetite ore involves both physical forces and chemical bonds.

[0077] In step 110, volatiles released from the reaction involving bio-oil are recovered to extract their energy value. They can also be used as chemical feedstocks for other chemical processes.

[0078] In the following claims and in the description preceding the invention, the word “comprise” or its variations, such as “comprises” or “comprising,” are used in an inclusive sense, except where the context otherwise requires it due to the language of expression or the necessary meaning, that is, to indicate the presence of the described features in various embodiments of the invention but not to exclude the presence or addition of further features.

Claims

1. A method for producing a solid composite material, the method comprising: Provides biomass crude material formed by heat treatment of a carbonaceous feedstock including biomass, said biomass crude material being able to harden at elevated temperatures; The bio-based coarse material is mixed with a solid or paste to form a coarse composite material; and The crude composite material is heated to undergo physical and chemical processes to produce a hardened solid composite material. The coarse composite material is formed by extrusion; The solid or paste-like substance mentioned above includes iron ore, and Heating the crude composite material further includes heating it in an oxidizing atmosphere to burn at least some of the biomass components, causing the iron ore to melt / sinter; and The hardened solid composite material constitutes part of the feed for a blast furnace or electric arc furnace.

2. The method according to claim 1, wherein the solid or paste further comprises a carbon material.

3. The method according to claim 1, wherein the solid further comprises metallurgical coke fines.

4. The method of claim 1, wherein the step of heating the crude composite material is performed to at least partially melt, sinter, or carbonize the composite material.

5. The method of claim 1, wherein the organic components in the crude composite material are burned by heating the crude composite material.

6. The method according to any one of claims 1 to 5 further comprises the steps of providing biochar formed by heat treatment of a carbonaceous feed comprising biomass and mixing the biochar with the biomass crude feed and the solid to form a crude composite material.

7. The method according to any one of claims 1 to 5 further comprises the step of providing a catalyst to increase the rate of hardening of the crude composite material.

8. The method of claim 6, further comprising the step of providing a catalyst to increase the rate of hardening of the crude composite material.

9. The method according to any one of claims 1 to 5, wherein the biomass feedstock is formed by pyrolysis, hydrothermal treatment, or liquefaction of a carbonaceous feedstock comprising biomass.

10. The method of claim 6, wherein the biomass feedstock is formed by pyrolysis, hydrothermal treatment, or liquefaction of a carbonaceous feedstock comprising biomass.

11. The method of claim 7, wherein the biomass feedstock is formed by pyrolysis, hydrothermal treatment, or liquefaction of a carbonaceous feedstock comprising biomass.

12. The method of claim 8, wherein the biomass feedstock is formed by pyrolysis, hydrothermal treatment, or liquefaction of a carbonaceous feedstock comprising biomass.

13. The method of claim 9, further comprising the step of recovering volatiles and other gases released by heating of the crude composite material.

14. The method of claim 13, wherein the recovered volatiles and other gases are combusted to provide energy for heating the crude composite material.

15. The method of claim 10, further comprising the step of recovering volatiles and other gases released by heating of the crude composite material.

16. The method of claim 15, wherein the recovered volatiles and other gases are combusted to provide energy for heating the crude composite material.

17. The method of claim 11, further comprising the step of recovering volatiles and other gases released by heating of the crude composite material.

18. The method of claim 17, wherein the recovered volatiles and other gases are combusted to provide energy for heating the crude composite material.

19. The method of claim 12, further comprising the step of recovering volatiles and other gases released by heating of the crude composite material.

20. The method of claim 19, wherein the recovered volatiles and other gases are combusted to provide energy for heating the crude composite material.

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