A method for distributing carbon footprint of metallurgical sludge treated by a rotary hearth furnace

Abstract

The present application relates to a kind of distribution methods of carbon footprint of metallurgical dust and sludge in rotary hearth furnace treatment, including determining the accounting boundary of rotary hearth furnace production process and calculating total carbon footprint of rotary hearth furnace process, calculating the carbon amount of reducing agent required for iron oxide reduction and zinc oxide reduction, calculating the carbon consumption ratio corresponding to iron and zinc oxide, calculating the carbon footprint of metallized pellet and zinc oxide to distribute total carbon emission of rotary hearth furnace to metallized pellet and zinc oxide product according to the calculation result.A kind of distribution method of carbon footprint of metallurgical dust and sludge in rotary hearth furnace treatment is designed using the present application, which can solve the problem that there is no distribution rule consistent with the reaction mechanism of the process in the prior art, and the existing distribution method focuses on the proportion of the result level, and fails to reflect the difference in carbon consumption between iron oxide reduction and zinc oxide reduction, making it difficult to reflect the influence of process parameters such as dezincification rate and metallization rate on carbon emission responsibility sharing, resulting in the problem of insufficient rationality and comparability of the distribution result.

Description

Technical Field

[0001] This invention relates to the field of carbon emission accounting and multi-product carbon footprint allocation technology in the iron and steel metallurgical process, specifically to a method for allocating the carbon footprint of metallurgical dust and sludge treated in a rotary hearth furnace. Background Technology

[0002] The rotary hearth furnace process is a crucial process in the steel industry for treating iron- and zinc-containing metallurgical dust and sludge. Through processes such as pelletizing, drying, roasting, and flue gas collection, it achieves the separation and synergistic recovery of iron and zinc, ultimately producing metallized pellets and zinc oxide. During this process, factors such as fuel combustion, the participation of carbon-containing reducing agents in the reaction, and carbon sequestration in the products collectively influence the carbon emissions of both the process and the products. Therefore, establishing a carbon footprint accounting method that aligns with the actual production characteristics of the rotary hearth furnace process has become a fundamental issue in green manufacturing and carbon management within the steel industry.

[0003] Existing carbon accounting methods for rotary hearth furnaces primarily focus on assessing the carbon footprint of a single main product. For multi-product systems involving both metallized pellets and zinc oxide, there is a lack of allocation rules consistent with the process reaction mechanism. Existing mass allocation, economic value allocation, and calorific value allocation methods often emphasize proportional division at the result level, failing to reflect the differences in carbon consumption between iron oxide reduction and zinc oxide reduction. They also struggle to reflect the actual impact of process parameters such as dezincification rate and metallization rate on carbon emission responsibility sharing, thus resulting in insufficient rationality and comparability of the allocation results.

[0004] Therefore, existing technologies have shortcomings and need to be improved and developed. Summary of the Invention

[0005] The present invention provides a method for allocating the carbon footprint of metallurgical dust and sludge in a rotary hearth furnace, which addresses the problem that existing technologies lack allocation rules consistent with the process reaction mechanism, and that existing allocation methods focus on proportional division at the result level, failing to reflect the difference in carbon consumption between iron oxide reduction and zinc oxide reduction, and making it difficult to reflect the actual impact of process parameters such as dezincification rate and metallization rate on carbon emission responsibility sharing, thus leading to insufficient rationality and comparability of allocation results.

[0006] This invention provides a method for allocating the carbon footprint of metallurgical dust and sludge in a rotary hearth furnace, comprising:

[0007] Determine the accounting boundary of the rotary hearth furnace production process, obtain activity data and carbon emission coefficients within the accounting boundary, and calculate the total carbon footprint of the rotary hearth furnace process;

[0008] The following parameters are obtained: input amount of reducing agent, carbon-oxygen ratio of green pellets fed into the furnace, carbon utilization rate, weight of iron oxide in pellets, weight of zinc oxide in pellets, metallization rate, dezincification rate, metallized pellet production, zinc oxide production, and residual zinc content in metallized pellets.

[0009] Based on the carbon-oxygen ratio, carbon utilization rate, weight of iron oxides in the pellets, weight of zinc oxides in the pellets, metallization rate, and dezincification rate of the green pellets fed into the furnace, the amount of reducing agent carbon required for the reduction of iron oxides and the amount of reducing agent carbon required for the reduction of zinc oxides are calculated respectively.

[0010] Based on the amount of carbon in the reducing agent required for the reduction of the iron oxide and the amount of carbon in the reducing agent required for the reduction of the zinc oxide, calculate the carbon consumption ratio corresponding to the iron oxide and zinc oxide.

[0011] Based on the total carbon footprint of the rotary hearth furnace process, the carbon consumption ratios of the iron oxide and zinc oxide, the production of the metallized pellets, and the production of zinc oxide, the carbon footprints of the metallized pellets and zinc oxide are calculated respectively.

[0012] Furthermore, the accounting boundary includes at least one of the following: raw material transportation system, raw material pretreatment system, pelletizing system, and pellet pressing system; green pellet drying system; rotary hearth furnace roasting system; zinc oxide collection system; and pellet cooling system.

[0013] Furthermore, the total carbon footprint of the rotary hearth furnace process... Calculate according to the following formula:

[0014] ;

[0015] in, The total carbon footprint of the rotary hearth furnace process, in units of ;

[0016] fuel or carbon-containing materials Activity data, in t or ;

[0017] fuel or carbon-containing materials The carbon emission factor, in units of or ;

[0018] This is activity data for electricity, expressed in kWh.

[0019] The carbon emission factor for electricity, in units of ;

[0020] For the final product Activity data, in tons;

[0021] For the final product The carbon emission factor, in units of .

[0022] Furthermore, the reducing agent includes one or more of pulverized coal, coke ash, graphite, and blast furnace dust.

[0023] Furthermore, the amount of carbon in the reducing agent required for the reduction of iron oxides. The amount of reducing agent carbon required for the reduction of zinc oxide Calculate according to the following formulas respectively:

[0024] ;

[0025] ;

[0026] in, This represents the amount of carbon in the reducing agent corresponding to the reduction of iron oxides, expressed in tons (t).

[0027] This represents the amount of carbon in the reducing agent corresponding to the reduction of zinc oxide, expressed in tons (t).

[0028] The carbon-to-oxygen ratio;

[0029] For carbon utilization rate;

[0030] This represents the weight of iron oxide in the pellet, expressed in tons (t).

[0031] The metallization rate of the metallized pellets;

[0032] The weight of zinc oxide in the pellet is expressed in tons (t).

[0033] The dezincification rate of the metallized pellets.

[0034] Furthermore, metallization rate and dezincification rate Calculate according to the following formulas respectively:

[0035] ;

[0036] ;

[0037] in, The amount of metallic iron in the metallized pellets;

[0038] This refers to the total iron content in the metallized pellets;

[0039] This represents the total amount of zinc in the pellets;

[0040] This represents the amount of residual zinc in the metallized pellets.

[0041] Furthermore, the carbon utilization rate The value range is 0.8 to 0.95.

[0042] Furthermore, the carbon consumption ratio of the zinc oxide reduction The carbon consumption ratio of the reduction of the iron oxide Calculate according to the following formulas respectively:

[0043] ;

[0044] ;

[0045] in, The proportion of carbon consumed in the reduction of zinc oxide;

[0046] The proportion of carbon consumed in the reduction of iron oxides.

[0047] Furthermore, the carbon footprint of the metallized pellets and the carbon footprint of the zinc oxide Calculate according to the following formulas respectively:

[0048] ;

[0049] ;

[0050] in, Carbon footprint per unit product for metallized pellets, in units of ;

[0051] The carbon footprint per unit product of zinc oxide, in units of ;

[0052] This refers to the production volume of metallized pellets, expressed in tons (t).

[0053] The figure represents zinc oxide production, expressed in tons (t).

[0054] Beneficial effects:

[0055] As can be seen from the above technical solutions, the present invention provides a method for distributing the carbon footprint of metallurgical dust and sludge in a rotary hearth furnace, which has the following beneficial effects:

[0056] 1. The carbon footprint allocation under the multi-product system of rotary hearth furnace is based on the actual carbon consumption of iron oxide reduction and zinc oxide reduction, which helps to make the allocation results correspond to the process reaction mechanism.

[0057] 2. Instead of simply dividing it by mass ratio, value ratio, or calorific value ratio, it forms a complete chain through total carbon footprint calculation, process parameter introduction, reaction carbon consumption measurement, and ratio conversion, making it more suitable for rotary hearth furnace co-recycling scenarios.

[0058] 3. Introducing parameters such as metallization rate, dezincification rate, and carbon utilization rate enables the allocation results to reflect changes in operating conditions, which helps to enhance the adaptability of the method to different raw material compositions and production states.

[0059] 4. It provides both total amount accounting formulas and product result calculation formulas, which facilitates continuous calculation from the process level to the product level and makes it easy to use in enterprise carbon accounting, product evaluation and process management.

[0060] 5. Outputting the unit product carbon footprint of metallized pellets and zinc oxide separately helps to improve the clarity of result attribution in multi-product systems and the operability of subsequent applications.

[0061] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other.

[0062] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0063] The accompanying drawings are not drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings, wherein:

[0064] Figure 1 This is a flowchart illustrating a method for allocating the carbon footprint of metallurgical dust and mud in a rotary hearth furnace, as described in this application.

[0065] Figure 2 This is the input and output table for the rotary hearth furnace production in the embodiments of this application. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0067] The terms "first," "second," and similar words used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "comprising" or "including" indicate that the element or object preceding "comprising" encompasses the features, integrals, steps, operations, elements, and / or components listed following "comprising" or "including," and do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or sets thereof. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0068] Rotary hearth furnace technology is a key technology for treating iron- and zinc-containing dust and sludge in the iron and steel industry. Its core purpose is to recover valuable elements from metallurgical solid waste. A typical process includes: batching, mixing, dust and sludge pelletizing, drying and screening, followed by feeding the pellets into the rotary hearth furnace. Under the high-temperature environment of coal gas combustion, the carbonaceous substances within the pellets undergo a self-reduction reaction, producing metallized pellets. During this process, volatile metals such as zinc are reduced and gasified and enter the flue gas system. Finally, after dust removal and cooling, the zinc oxide product is enriched, thus achieving the simultaneous recovery of iron and zinc.

[0069] Carbon emissions during the rotary hearth furnace production process mainly come from two aspects: first, emissions from fuel combustion, namely carbon emissions generated by the combustion of fuels such as coal gas; and second, emissions from the use of reducing agents, namely carbon emissions generated by the reduction of metal oxides by carbon-containing materials (such as coke ash, coal powder, and ore ash) within the pellets.

[0070] A key challenge in current carbon emission accounting for rotary hearth furnaces is the lack of a suitable carbon emission allocation method for multi-product systems. While existing carbon accounting standards and specifications have established a basic framework for accounting boundaries, content, and methods, they have not yet clearly defined the carbon emission allocation for the two symbiotic products: metallized pellets and zinc oxide. In current practice, mass allocation or economic value allocation methods are often used to distribute total carbon emissions to the two product categories. However, these methods fail to consider the differences in carbon emission mechanisms and contributions of different products during actual production, raising questions about the rationality and accuracy of the allocation results. Furthermore, existing methods struggle to accurately reflect the complex physicochemical reaction processes within the rotary hearth furnace and their impact on carbon emissions, necessitating the development of a targeted allocation model closely integrated with the process mechanisms.

[0071] Currently, there is no universally accepted standard method for allocating the total carbon footprint of a rotary hearth furnace between metallized pellets and zinc oxide. Referring to carbon footprint accounting practices in other fields, the following allocation approaches are often adopted, but all have certain limitations:

[0072] (1) The quality allocation method and its limitations

[0073] Method principle: The total carbon footprint is allocated based on the mass ratio of metallized pellets to zinc oxide products.

[0074] Limitations: This method completely ignores the actual differences in energy consumption and carbon emissions among different products during the production process. Although zinc oxide accounts for a small percentage by mass, its reduction, volatilization, and recycling processes consume a significant amount of energy. Therefore, the mass allocation method severely underestimates the carbon footprint of zinc oxide while overestimating the carbon footprint of metallized pellets, violating the principle of fairness in carbon emission responsibility.

[0075] (2) The economic value distribution method and its limitations

[0076] Method principle: Allocation is based on the market value ratio of metallized pellets and zinc oxide.

[0077] Limitations: While this method considers economic factors, its fairness is susceptible to market price fluctuations. Zinc oxide prices fluctuate significantly with zinc prices, while metallized pellet prices are relatively stable. When zinc oxide prices are high, its share of the carbon footprint increases, but this does not match the actual energy consumption in the production process.

[0078] (3) Calorific value allocation method and its limitations

[0079] Method principle: The distribution is based on the ratio of calorific value of metallized pellets and zinc oxide.

[0080] Limitations: Metallized pellets have a high calorific value, while zinc oxide products have an extremely low calorific value. Allocating carbon footprint based on calorific value would result in an excessively small proportion of carbon footprint allocated to zinc oxide products, failing to accurately reflect the actual energy consumed during the high-temperature reduction and volatilization process in the rotary hearth furnace.

[0081] (4) System extension method and its limitations

[0082] Method Principle: This method avoids direct allocation, instead treating zinc oxide as a byproduct and attributing its emission reduction benefits to replacing primary materials. Specifically, it calculates the carbon emissions that could be avoided by replacing the equivalent amount of primary zinc oxide production and deducts this portion from the total carbon emissions of the rotary hearth furnace.

[0083] Limitations: This method is computationally complex, requires the identification of credible alternatives (such as replacing the process of producing zinc oxide from primary zinc ore), and faces problems such as difficulty in defining the boundaries of the alternative system and disputes over the selection of alternatives.

[0084] Therefore, embodiments of the present invention provide a method for allocating the carbon footprint of metallurgical dust and sludge in a rotary hearth furnace, referring to... Figure 1 ,include:

[0085] Step S102: Determine the accounting boundary of the rotary hearth furnace production process, obtain activity data and carbon emission coefficients within the accounting boundary, and calculate the total carbon footprint of the rotary hearth furnace process.

[0086] Step S104: Obtain the input amount of reducing agent, the carbon-oxygen ratio of green pellets entering the furnace, the carbon utilization rate, the weight of iron oxide in the pellets, the weight of zinc oxide in the pellets, the metallization rate, the dezincification rate, the production of metallized pellets, the production of zinc oxide, and the residual zinc content in the metallized pellets.

[0087] Step S106: Based on the carbon-oxygen ratio of the green pellets entering the furnace, carbon utilization rate, weight of iron oxides in the pellets, weight of zinc oxides in the pellets, metallization rate, and dezincification rate, calculate the amount of reducing agent carbon required for the reduction of iron oxides and the amount of reducing agent carbon required for the reduction of zinc oxides, respectively.

[0088] Step S108: Calculate the carbon consumption ratios of iron oxide and zinc oxide based on the amount of reducing agent carbon required for the reduction of iron oxide and zinc oxide.

[0089] Step S110: Based on the total carbon footprint of the rotary hearth furnace process, the carbon consumption ratios of iron oxide and zinc oxide, the production of metallized pellets, and the production of zinc oxide, calculate the carbon footprint of metallized pellets and the carbon footprint of zinc oxide, respectively.

[0090] First, determine the accounting boundary of the rotary hearth furnace production process, obtain activity data and correlation coefficients within the boundary, and calculate the total carbon footprint of the process. Then, obtain parameters such as reducing agent input, carbon-oxygen ratio of green pellets entering the furnace, carbon utilization rate, iron oxide weight, zinc oxide weight, metallization rate, dezincification rate, and product yield. Further, calculate the reducing agent carbon consumption corresponding to iron oxide reduction and zinc oxide reduction respectively. Then, obtain the carbon consumption ratio between the two. Finally, based on this ratio, allocate the total carbon footprint of the rotary hearth furnace process to metallized pellets and zinc oxide products.

[0091] The focus is not simply on total carbon accounting, but on establishing a complete methodological chain encompassing total carbon footprint accounting, reaction carbon consumption breakdown, and multi-product carbon footprint allocation. Using the actual carbon consumption of iron oxide reduction and zinc oxide reduction as an intermediary bridge, a quantitative correspondence is established between the carbon emission responsibilities of the two types of products in the rotary hearth furnace co-recycling process. This forms a general allocation framework applicable to the rotary hearth furnace co-recycling process, which helps avoid mechanically allocating total process carbon emissions based on product quality or price, thereby improving the process-specificity and accounting consistency of multi-product carbon footprint allocation.

[0092] In some embodiments, the accounting boundary includes at least one of a raw material transportation system, a raw material pretreatment system, a pelletizing system, and a pellet pressing system, a green pellet drying system, a rotary hearth furnace roasting system, a zinc oxide collection system, and a pellet cooling system.

[0093] In some embodiments, the total carbon footprint of the rotary hearth furnace process Calculate according to the following formula:

[0094] ;

[0095] in, Total carbon footprint of the rotary hearth furnace process, in units of ;

[0096] fuel or carbon-containing materials Activity data, in t or ;

[0097] fuel or carbon-containing materials The carbon emission factor, in units of or ;

[0098] This is activity data for electricity, expressed in kWh.

[0099] The carbon emission factor for electricity, in units of ;

[0100] For the final product Activity data, in tons;

[0101] For the final product The carbon emission factor, in units of .

[0102] The carbon emission coefficients for various materials are carbon emission factors published by industries, organizations, or countries, or carbon emission coefficients calculated based on relevant standards. The final products are metallized pellets and zinc oxide products.

[0103] The main carbon flows within the rotary hearth furnace process are incorporated into the accounting model, rather than solely counting combustion emissions. For processes involving reducing agents in the reaction and accompanying carbon sequestration in the product, calculating only fuel-side emissions is insufficient as a reliable basis for subsequent allocation. The total carbon footprint calculation formula unifies multiple input and output factors under a single caliber, providing a premise for subsequent allocation calculations. This helps to make the calculation of the total carbon footprint of the process more closely reflect the actual carbon flow distribution in the rotary hearth furnace, providing a more stable total basis for subsequent product allocation results.

[0104] In some embodiments, the reducing agent includes one or more of pulverized coal, coke ash, graphite, and blast furnace dust.

[0105] The carbon footprint allocation method for metallurgical dust and sludge treatment provided in this application embodiment does not base the carbon footprint allocation on a single static parameter. Instead, it introduces multiple parameters reflecting the degree of reduction reaction, product formation, and process state into the same method chain, so that the allocation result is adapted to the process state, rather than using a fixed ratio allocation that is detached from the process conditions. This is beneficial to improving the method's adaptability to different material types, different reduction states, and different product output conditions, and allows the allocation result to be adjusted according to changes in operating conditions.

[0106] By limiting the sources of carbon-containing reducing agents, such as pulverized coal, coke ash, graphite, and blast furnace dust, the method is made more suitable for actual industrial production conditions.

[0107] In some embodiments, the amount of reducing agent carbon required for the reduction of iron oxides The amount of reducing agent carbon required for the reduction of zinc oxide Calculate according to the following formulas respectively:

[0108] ;

[0109] ;

[0110] in, This represents the amount of carbon in the reducing agent corresponding to the reduction of iron oxides, expressed in tons (t).

[0111] This represents the amount of carbon in the reducing agent corresponding to the reduction of zinc oxide, expressed in tons (t).

[0112] The carbon-to-oxygen ratio;

[0113] Carbon utilization rate; in some embodiments, carbon utilization rate The value range is 0.8~0.95. The value range is based on the actual process conditions, within the operable engineering range, and takes into account the real working conditions in industrial implementation. This is conducive to controlling the parameter value range, reducing the fluctuation of results caused by arbitrarily selecting carbon utilization rate, and improving the engineering applicability of the calculation results.

[0114] This represents the weight of iron oxide in the pellet, in tons (t).

[0115] The metallization rate of the metallized pellets;

[0116] The weight of zinc oxide in the pellet is expressed in tons (t).

[0117] The dezincification rate of the metallized pellets.

[0118] Instead of directly allocating carbon emissions based on product outcome ratios, we first calculate the actual carbon consumption corresponding to the two reaction paths based on the stoichiometric relationship and process status of iron oxide reduction and zinc oxide reduction, and then establish the basis for allocation between products based on this. This transforms the reaction mechanism into a basis for carbon footprint allocation, which helps to make the carbon footprint allocation correspond to the actual reduction reaction that occurs in the rotary hearth furnace, thereby reducing the deviation caused by allocating solely based on product outcome.

[0119] In some embodiments, metallization rate and dezincification rate Calculate according to the following formulas respectively:

[0120] ;

[0121] ;

[0122] in, The amount of metallic iron in the metallized pellets;

[0123] This refers to the total iron content in the metallized pellets;

[0124] This refers to the total amount of zinc in the pellets;

[0125] This represents the amount of residual zinc in the metallized pellets.

[0126] In some embodiments, the carbon consumption ratio of zinc oxide reduction The carbon consumption ratio of iron oxide reduction Calculate according to the following formulas respectively:

[0127] ;

[0128] ;

[0129] in, The proportion of carbon consumed in the reduction of zinc oxide;

[0130] The proportion of carbon consumed in the reduction of iron oxides.

[0131] Establishing a bridge between the amount of carbon in the reaction and the distribution ratio is beneficial for converting complex reduction reaction analysis results into directly usable proportional parameters, which facilitates implementation in actual accounting and carbon management.

[0132] In some embodiments, the carbon footprint of metallized pellets And the carbon footprint of zinc oxide Calculate according to the following formulas respectively:

[0133] ;

[0134] ;

[0135] in, The unit product carbon footprint of metallized pellets, in units of ;

[0136] The carbon footprint per unit product of zinc oxide, in units of ;

[0137] This refers to the production volume of metallized pellets, expressed in tons (t).

[0138] The figure represents zinc oxide production, expressed in tons (t).

[0139] By combining the production of metallized pellets and zinc oxide, the unit carbon footprint of the two products can be calculated separately. This allows for the generation of independent carbon footprint results for metallized pellets and zinc oxide, thereby supporting subsequent processes such as product carbon management, process evaluation, and accounting comparison.

[0140] The following is another embodiment of a method for allocating the carbon footprint of metallurgical dust and sludge in a rotary hearth furnace:

[0141] (1) Determine the accounting boundary and total carbon footprint of the rotary hearth furnace production process. The accounting boundary of rotary hearth furnace production includes at least one of the following: raw material transportation system, raw material pretreatment system, pelletizing system, and pellet pressing system; green pellet drying system; rotary hearth furnace roasting system; zinc oxide collection system; and pellet cooling system. Calculate the total carbon emissions of rotary hearth furnace production. Taking the processing of 1 ton of pellets as an example, calculate the carbon emissions, referring to... Figure 2 , Figure 2 The table shown is the input and output table for rotary hearth furnace production.

[0142] Substitute the relevant data from Table 2 and calculate based on the formula:

[0143] The calculated result is 345.197. .

[0144] (2) Determine the amount of reducing agent carbon required for the reduction of iron oxide and zinc oxide in the metallized pellets, and calculate the actual carbon consumption ratio of the two reduction reactions in combination with the process parameters.

[0145] The pellets have a carbon-to-oxygen ratio of 0.75, a carbon utilization rate of 0.85, a dezincification rate of 88%, a metallization rate of 75%, and contain 0.53 t of iron oxides and 0.072 t of zinc oxides. (Based on the formula...) achievable Based on the formula achievable .

[0146] (3) Determine the carbon consumption ratio by substituting the result obtained in step (2) into the formula. , can be obtained Substitute into the formula , can be obtained .

[0147] (4) Based on , ,Depend on Figure 2 From the data, we know that the production of metallized pellets is 0.6756 t, and the production of zinc oxide is 0.0547 t. Therefore, the carbon emissions for metallized pellets and zinc oxide are 462.61 t each. 596.99 Therefore, the surplus calculation results will allocate the total carbon emissions of the rotary hearth furnace to the metallized pellets and zinc oxide products.

[0148] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A method for distributing the carbon footprint of metallurgical dust and sludge in a rotary hearth furnace, characterized in that, include: Determine the accounting boundary of the rotary hearth furnace production process, obtain activity data and carbon emission coefficients within the accounting boundary, and calculate the total carbon footprint of the rotary hearth furnace process; The following parameters are obtained: input amount of reducing agent, carbon-oxygen ratio of green pellets fed into the furnace, carbon utilization rate, weight of iron oxide in pellets, weight of zinc oxide in pellets, metallization rate, dezincification rate, metallized pellet production, zinc oxide production, and residual zinc content in metallized pellets. Based on the carbon-oxygen ratio, carbon utilization rate, weight of iron oxides in the pellets, weight of zinc oxides in the pellets, metallization rate, and dezincification rate of the green pellets fed into the furnace, the amount of reducing agent carbon required for the reduction of iron oxides and the amount of reducing agent carbon required for the reduction of zinc oxides are calculated respectively. Based on the amount of carbon in the reducing agent required for the reduction of the iron oxide and the amount of carbon in the reducing agent required for the reduction of the zinc oxide, calculate the carbon consumption ratio corresponding to the iron oxide and zinc oxide. Based on the total carbon footprint of the rotary hearth furnace process, the carbon consumption ratios of the iron oxide and zinc oxide, the production of the metallized pellets, and the production of zinc oxide, the carbon footprints of the metallized pellets and zinc oxide are calculated respectively.

2. The method for allocating the carbon footprint of metallurgical dust and sludge in a rotary hearth furnace according to claim 1, characterized in that, The accounting boundary includes at least one of the following: raw material transportation system, raw material pretreatment system, pelletizing system and pellet pressing system, green pellet drying system, rotary hearth furnace roasting system, zinc oxide collection system and pellet cooling system.

3. The method for allocating the carbon footprint of metallurgical dust and sludge in a rotary hearth furnace according to claim 1, characterized in that, The total carbon footprint of the rotary hearth furnace process Calculate according to the following formula: ； in, The total carbon footprint of the rotary hearth furnace process, in units of ; fuel or carbon-containing materials Activity data, in t or ; fuel or carbon-containing materials The carbon emission factor, in units of or ; This is activity data for electricity, expressed in kWh. The carbon emission factor for electricity, in units of ; For the final product Activity data, in tons; For the final product The carbon emission factor, in units of .

4. The method for allocating the carbon footprint of metallurgical dust and sludge in a rotary hearth furnace according to claim 1, characterized in that, The reducing agent includes one or more of the following: pulverized coal, coke ash, graphite, and blast furnace dust.

5. The method for allocating the carbon footprint of metallurgical dust and sludge in a rotary hearth furnace according to claim 4, characterized in that, The amount of carbon in the reducing agent required for the reduction of iron oxides The amount of reducing agent carbon required for the reduction of zinc oxide Calculate according to the following formulas respectively: ； ； in, This represents the amount of carbon in the reducing agent corresponding to the reduction of iron oxides, expressed in tons (t). This represents the amount of carbon in the reducing agent corresponding to the reduction of zinc oxide, expressed in tons (t). The carbon-to-oxygen ratio; For carbon utilization rate; This represents the weight of iron oxide in the pellet, expressed in tons (t). The metallization rate of the metallized pellets; The weight of zinc oxide in the pellet is expressed in tons (t). The dezincification rate of the metallized pellets.

6. The method for allocating the carbon footprint of metallurgical dust and sludge in a rotary hearth furnace according to claim 5, characterized in that, Metallization rate and dezincification rate Calculate according to the following formulas respectively: ； ； in, This refers to the amount of metallic iron in the metallized pellets; This refers to the total iron content in the metallized pellets; This refers to the total amount of zinc in the pellets; This represents the amount of residual zinc in the metallized pellets.

7. The method for allocating the carbon footprint of metallurgical dust and sludge in a rotary hearth furnace according to claim 5, characterized in that, The carbon utilization rate The value range is 0.8 to 0.

95.

8. The method for allocating the carbon footprint of metallurgical dust and sludge in a rotary hearth furnace according to claim 5, characterized in that, The carbon consumption ratio of the zinc oxide reduction The carbon consumption ratio of the reduction of the iron oxide Calculate according to the following formulas respectively: ； ； in, The proportion of carbon consumed in the reduction of zinc oxide; The proportion of carbon consumed in the reduction of iron oxides.

9. The method for allocating the carbon footprint of metallurgical dust and sludge in a rotary hearth furnace according to claim 8, characterized in that, The carbon footprint of the metallized pellets and the carbon footprint of the zinc oxide Calculate according to the following formulas respectively: ； ； in, Carbon footprint per unit product for metallized pellets, in units of ; The carbon footprint per unit product of zinc oxide, in units of ; This represents the production volume of metallized pellets, expressed in tons (t). The figure represents zinc oxide production, expressed in tons (t).

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