Life cycle evaluation-based carbon footprint accounting and data quality evaluation method for copper concentrate smelting copper product

Abstract

The invention discloses a copper concentrate smelting copper product carbon footprint accounting and data quality evaluation method based on life cycle evaluation. The method comprises the following steps: firstly, determining whether a product object of carbon footprint accounting is crude copper, anode copper or electrolytic copper; then, according to the product type, defining the boundary of a carbon footprint accounting system; collecting related data in a system boundary range corresponding to the product; establishing a life cycle list for the collected data; and finally, carrying out carbon footprint accounting on the product. According to the method, different carbon footprint accounting models are established for an oxygen-enriched smelting system, a converter blowing system, an anode refining system and an electrolytic refining system for smelting copper products from the copper concentrate, and comprehensiveness and accuracy of carbon footprint calculation are ensured. According to the method, the process and the system boundary are standardized, so that the data has comprehensiveness, objectivity, accuracy and comparability. According to the data quality evaluation method provided by the invention, the data precision and reliability of carbon footprint accounting are remarkably improved, and the accuracy and normalization of carbon emission accounting of the copper smelting product are improved.

Description

Technical Field

[0001] The present invention relates to a method for calculating the carbon footprint and evaluating the data quality of copper products smelted from copper concentrates based on life cycle assessment, belonging to the technical field of carbon emissions. Background Art

[0002] With the progress of industrial demands, due to its excellent electrical conductivity, thermal conductivity, corrosion resistance, and good ductility, the demand for copper products is increasing day by day. The national electrolytic copper output in 2023 was 13.2557 million tons, second only to primary aluminum among non-ferrous metals, and the output increased by 66% compared with that in 2015. As one of the important strategic reserve resources, copper is of crucial importance and indispensability in many industrial fields such as the electronic and electrical industries and the machinery manufacturing field. The production process from copper concentrates to electrolytic copper is numerous, involving multiple links, having many intermediate products, and consuming a large amount of electric energy and fossil fuels, directly or indirectly causing a large amount of carbon emissions. The "Quota of Energy Consumption per Unit Product of Non-ferrous Heavy Metal Smelting Enterprises" (GB 25323-2023) issued in 2023 has standard requirements for the statistical scope of various links in copper smelting, but it only provides a standard for calculating the comprehensive energy consumption of copper products, and the emission accounting method for copper products remains unclear.

[0003] Life cycle assessment (LCA) is a systematic and standardized method for quantitatively evaluating the environmental impacts of products, services, or activities throughout their life cycles. Due to the advantages of LCA such as being systematic, quantitative, standardized, and universal, it is an important method for calculating carbon footprints. However, due to the characteristics of the LCA method such as numerous steps, complex content, and many evaluation methods, the operation is relatively difficult. At the same time, there are few current studies on carbon footprint accounting related to copper smelting, and the research has the situation of unclear definition of system boundaries and incomplete accounting. Therefore, there is an urgent need for a method to define the system boundaries of the production process from copper concentrates to copper smelting products, and a method to evaluate the quality of carbon footprint accounting data for copper smelting products. Summary of the Invention

[0004] The present invention provides a method for calculating the carbon footprint and evaluating the data quality of copper products smelted from copper concentrates based on life cycle assessment, so as to solve the technical problems of unclear system boundaries and incomplete accounting in the current carbon footprint accounting of copper smelting products, and improve the accuracy and standardization of carbon emission accounting for copper smelting products.

[0005] On the one hand, the present invention provides a method for calculating the carbon footprint of copper products smelted from copper concentrates based on life cycle assessment, including:

[0006] (1) Defining the evaluation object

[0007] Determining whether the product object for carbon footprint accounting is blister copper, anode copper, or electrolytic copper;

[0008] (2) Set the system boundary

[0009] Define the system boundary of carbon footprint accounting according to the product type;

[0010] The system boundary of blister copper production is the oxygen-enriched smelting system and the converter blowing system; the system boundary of anode copper production is the combination of the oxygen-enriched refining system, the converter blowing system and the anode refining system; the system boundary of electrolytic copper production is the combination of the oxygen-enriched refining system, the converter blowing system, the anode refining system and the electrolytic refining system;

[0011] Among them, the oxygen-enriched smelting system consists of an oxygen-enriched top-blown smelting furnace and a settling electric furnace or other separation equipment. The converter blowing system only includes converters. The anode refining system only includes anode refining furnaces. The electrolytic refining system only includes electrolytic refining workshops. Ancillary processes such as flue gas acid-making, slag treatment and anode slime treatment are not included. At the same time, links such as public equipment maintenance and personnel life are ignored.

[0012] (3) Data collection

[0013] Collect foreground data within the system boundary corresponding to the product and determine the source of background data;

[0014] (4) Establish a life cycle inventory

[0015] Input the collected data to establish a life cycle inventory;

[0016] (5) Carbon footprint accounting

[0017] Establish carbon footprint accounting models for blister copper, anode copper and electrolytic copper products, and account for the carbon footprint of the products in combination with the collected data;

[0018] C 粗铜 = C 火法精炼系统 + C 转炉吹炼系统

[0019] C 阳极铜 = C 火法精炼系统 + C 转炉吹炼系统 + C 阳极精炼系统

[0020] C 电解铜 = C 火法精炼系统 + C 转炉吹炼系统 + C 阳极精炼系统 + C 电解精炼系统

[0021] In the formula, C 粗铜 , C 阳极铜 and C 电解铜 are the carbon footprint accounting results of blister copper, anode copper and electrolytic copper products respectively. C 富氧熔炼系统 , C 转炉吹炼系统 , C阳极精炼系统 and C 电解精炼系统 are the carbon emissions of the four process links of the oxygen-enriched smelting system, converter blowing system, anode refining system, and electrolytic refining system, respectively.

[0022] Preferably, the foreground data mainly collects data on the consumption of raw and auxiliary materials, energy consumption, fuel consumption, and direct emissions in the product system. Among them, the data on the consumption of raw and auxiliary materials only focuses on the data with an input ratio greater than 1%, and all the energy data consumed by the main equipment needs to be collected. The background data comes from local or international databases, product carbon footprint (CFP) or environmental product declaration (EPD) reports certified by third-party authoritative institutions, high-quality academic literature published publicly, or other representative data. Priority is given to using local databases that match the product production location.

[0023] Preferably, a data list is established based on the collected foreground data, and the background data streams corresponding to each foreground data involving background data are listed. The result of the data quality assessment of the foreground data, that is, the geometric standard deviation (GSD) of the data, is also listed in the list table. An example of the data list description is shown in Table 1.

[0024] Table 1 Example of the input data list for carbon accounting of copper smelting products

[0025]

[0026] Preferably, the calculation results are summarized, as shown in Table 2, which is the result of the product carbon footprint accounting.

[0027] Table 2 Results of product carbon footprint accounting

[0028] Process Carbon emission accounting value Carbon emission unit CV value Oxygen-enriched smelting system <![CDATA[t CO2 eq. / t product]]> Converter blowing system <![CDATA[t CO2 eq. / t product]]> Anode refining system <![CDATA[t CO2 eq. / t product]]> Electrolytic refining system <![CDATA[t CO2 eq. / t product]]> Product carbon footprint accounting result t CO2 eq. / t product

[0029] On the other hand, the present invention provides a data quality evaluation system, specifically including:

[0030] Using the pedigree method to evaluate the uncertainty of life cycle inventory data and providing the probability distribution of input parameters for the subsequent Monte Carlo simulation;

[0031] First, referring to Table 3, according to the actual situation of the data source, the quality of each data is scored from 1 to 5 from high to low from 5 index perspectives.

[0032] Table 3 Data quality analysis pedigree matrix - indicators and scores

[0033]

[0034] Referring to Table 4, different GSDs are assigned to the 5 indicators according to different scores, and the total GSD of each inventory data category is calculated according to the following formula:

[0035]

[0036] In the formula, GSD Total is the total geometric standard deviation value for each inventory data category, GSD R is the geometric standard deviation value of the reliability of the indicator data, GSD C is the geometric standard deviation value of the integrity of the indicator data, GSD T is the geometric standard deviation value of the time correlation of the indicator, GSD G is the geometric standard deviation value of the regional correlation of the indicator, GSD F is the geometric standard deviation value of the technical correlation of the indicator, GSD Basic is the basic geometric standard deviation value of the data, which is derived from the experts' judgment of the uncertainty of the original data and specifically depends on the data processing type and the way of establishing the process model.

[0037] Table 4 Data Quality Analysis Pedigree Matrix - GSD Values Corresponding to Scores

[0038] Indicator / score 1 2 3 4 5 Data reliability (R) 1 1.05 1.1 1.2 1.5 Data integrity (C) 1 1.02 1.05 1.1 1.2 Temporal relevance (T) 1 1.03 1.1 1.2 1.5 Geographical relevance (G) 1 1.01 1.02 1.05 1.1 Technical relevance (F) 1 1.05 1.2 1.5 2.0

[0039] Evaluating the Data Quality of Carbon Footprint Accounting Results Using the Monte Carlo Simulation Method

[0040] Use data analysis software to perform 1000 Monte Carlo simulations on the inventory data and results, and calculate the CV value according to the simulation results. The CV value is used to describe the accuracy of the simulation results. The data accuracy of carbon footprint accounting determined by the CV value is shown in Table 5.

[0041] Among them, the calculation formula of CV is as follows:

[0042]

[0043] Table 5 Criteria for Judging the Data Accuracy of Carbon Footprint Accounting

[0044]

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The present invention provides a systematic and precise carbon footprint accounting method. Different carbon footprint accounting models are established for the oxygen-enriched smelting system, converter blowing system, anode refining system, and electrolytic refining system of copper products smelted from copper concentrates, effectively avoiding the allocation process while ensuring the comprehensiveness and accuracy of carbon footprint calculation. And a unified accounting method for the carbon footprints of three main copper products smelted from copper concentrates, namely blister copper, anode copper, and electrolytic copper, is constructed according to the differences of products, filling the blank of the standardized carbon footprint accounting process in the prior art. The present invention standardizes the process and clarifies the system boundary, not only improving the consistency of data, but also providing a reliable basis for comparative analysis in the industry, making up for the lack of the current carbon footprint accounting method for copper smelting products, and having the characteristics of comprehensiveness, objectivity, precision, and comparability.

[0047] In addition, the present invention proposes a complete set of data quality calculation and evaluation methods. Through scientific data collection, verification, processing processes, and result evaluation, the data accuracy and reliability of carbon footprint accounting are significantly improved. This not only enhances the data accuracy of carbon footprint accounting, but also provides strong support for subsequent optimization decisions, and at the same time improves the current carbon footprint accounting data quality analysis method. Brief Description of the Drawings

[0048] Figure 1 : is a schematic flow chart of the method of the present invention.

[0049] Figure 2 : is a system boundary diagram of copper smelting product carbon accounting defined by the present invention. Detailed Embodiments

[0050] In order to make the objectives, technical solutions, and advantages 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 in the present invention. Obviously, the described examples are some embodiments of the present invention, rather than all embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention.

[0051] The following combines Figure 1 - Figure 2 to describe the carbon footprint accounting and data quality assessment method for copper products smelted from copper concentrates based on life cycle assessment provided by the embodiments of the present invention.

[0052] Embodiment

[0053] Account for the product carbon footprint of a certain copper smelter and conduct data quality analysis. As Figure 1 shown, it includes the following steps:

[0054] Step (1): Based on the data of the copper smelter, determine that its final product is electrolytic copper, the functional unit is 1t of electrolytic copper, and the accounting objective is the carbon footprint accounting of 1t of electrolytic copper.

[0055] Step (2): Determine that all the processes involved in this copper smelter are as follows: ① The oxygen-enriched top-blown smelting furnace processes copper concentrate. The tail gas from the smelting furnace enters the sulfuric acid production system for sulfuric acid preparation after waste heat recovery, and the slag from the smelting furnace is regularly removed and quenched with water for external sale and disposal; ② Then, a settling electric furnace is used for slag-copper separation, and the separated slag enters a rotary kiln in another production line for treatment; ③ The separated copper matte (blister copper) is sent to a converter for blowing to produce blister copper, and the tail gas from the converter enters the sulfuric acid production system for sulfuric acid preparation after waste heat recovery; ④ The blister copper is sent to an anode refining furnace to produce anode copper plates, and the anode slime is regularly removed and uniformly fed into another electrolysis system for valuable metal recovery; ⑤ The anode copper plates are sent to the electrolysis process to produce electrolytic copper.

[0056] Further, as Figure 2 shown, it is determined that the electrolytic copper production of this plant involves 4 systems defined in the present invention, namely, the oxygen-enriched smelting system, the converter blowing system, the anode refining system, and the electrolysis system. The boundary of the blister copper production system is the oxygen-enriched smelting system and the converter blowing system; the boundary of the anode copper production system is the combination of the oxygen-enriched refining system, the converter blowing system, and the anode refining system.

[0057] That is, in this embodiment, the system boundary for carbon accounting is the oxygen-enriched smelting system, the converter blowing system, the anode refining system, and the electrolysis system. The oxygen-enriched smelting system consists of an oxygen-enriched top-blown smelting furnace and a settling electric furnace, the converter blowing system consists only of a converter, the anode refining system consists only of an anode refining furnace, and the electrolysis refining system consists only of an electrolysis refining workshop.

[0058] Step (3): According to the product system boundary defined in Step (2), collect foreground data. Since there is background data applicable to the evaluation object, the Ecoinvent database is selected as the source of background data.

[0059] Step (4): Establish a life cycle inventory based on the data collected in Step (3), and perform GSD calculation on the input data, as shown in Table 6:

[0060] Table 6 List of Input Data for Carbon Accounting of Electrolytic Copper in a Copper Smelter

[0061]

[0062]

[0063]

[0064] Step (5): Conduct carbon footprint accounting

[0065] Establish a carbon footprint accounting model for blister copper, anode copper, and electrolytic copper products, and calculate the carbon footprint of the products based on the collected data;

[0066] C 粗铜 = C 火法精炼系统 + C 转炉吹炼系统

[0067] C 阳极铜 = C 火法精炼系统 + C 转炉吹炼系统 + C 阳极精炼系统

[0068] C 电解铜 = C 火法精炼系统 + C 转炉吹炼系统 + C 阳极精炼系统 + C 电解精炼系统

[0069] In the formula, C 粗铜 , C 阳极铜 , and C 电解铜 are the carbon footprint accounting results of blister copper, anode copper, and electrolytic copper products respectively, and C 富氧熔炼系统 , C 转炉吹炼系统 , C 阳极精炼系统 , and C 电解精炼系统 are the carbon emissions of the four process links of the oxygen-enriched smelting system, converter blowing system, anode refining system, and electrolytic refining system respectively.

[0070] The carbon footprint models of the four process links of the oxygen-enriched refining system, converter blowing system, anode refining system, and electrolytic refining system are respectively:

[0071] EF 富氧熔炼系统,i = ∑EF 富氧熔炼系统,i,j

[0072] C 富氧熔炼系统 = ∑(EF 富氧熔炼系统,i × Q i )

[0073] EF 转炉吹炼系统,i = ∑EF 转炉吹炼系统,i,j

[0074] C 转炉吹炼系统 = ∑(EF 转炉吹炼系统,i × Q i )

[0075] EF 阳极精炼系统,i = ∑EF 阳极精炼系统,i,j

[0076] C 阳极精炼系统 = ∑(EF 阳极精炼系统,i × Q i )

[0077] EF电解精炼系统,i = ∑EF 电解精炼系统,i,j

[0078] C 电解精炼系统 = ∑(EF 电解精炼系统,i × Q i )

[0079] where EF represents the actual greenhouse gas emissions, Q is the greenhouse gas emission factor, the subscript i represents different types of greenhouse gases, and the subscript j represents different source links of greenhouse gases, which are raw and auxiliary material consumption, energy consumption, fuel consumption, and direct emissions respectively.

[0080] Perform quality assessment on the data in steps (4) and (5), where the uncertainty of the life cycle inventory data in step (4) is evaluated using the pedigree method, and the results are shown in Table 6. Specifically, corresponding scores are assigned respectively from data reliability, data integrity, index time correlation, regional correlation, and technical correlation according to the pedigree matrix, and combined with the basic uncertainty of the data, the geometric standard deviation of the inventory data is calculated according to various scores.

[0081]

[0082] where GSD Total is the total geometric standard deviation value for each inventory data category, GSD R is the geometric standard deviation value of index data reliability, GSD C is the geometric standard deviation value of index data integrity, GSD T is the geometric standard deviation value of index time correlation, GSD G is the geometric standard deviation value of index regional correlation, GSD F is the geometric standard deviation value of index technical correlation, GSD Basic is the basic geometric standard deviation value of the data.

[0083] Analyze the carbon footprint accounting results in step (5). Specifically, use OpenLCA 2.4.0 software to calculate the data in the life cycle inventory established in step (4), and at the same time perform 1000 Monte Carlo simulations to calculate the CV value. The calculation results and data quality evaluation are shown in Table 7. The carbon footprint accounting result for producing 1 t of electrolytic copper is 1379.95811 kg of carbon dioxide, the CV value is 3.5%, and the data quality is good.

[0084] Table 7 Product Carbon Footprint Accounting Results

[0085] Process Carbon emission accounting value Carbon emission unit CV value Oxygen-enriched smelting system 412.9220668 <![CDATA[kg CO2 eq. / t electrolytic copper]]> 4.33％ Converter blowing system 715.4505181 <![CDATA[kg CO2 eq. / t electrolytic copper]]> 5.83％ Anode refining system 6.740793884 <![CDATA[kg CO2 eq. / t electrolytic copper]]> 5.15％ Electrolytic refining system 244.8447317 <![CDATA[kg CO2 eq. / t electrolytic copper]]> 5.13％ Carbon footprint accounting of electrolytic copper 1379.95811 <![CDATA[kg CO2]]> 3.51％

[0086] The methods of steps (1)-(5) described above can be used for the carbon footprint accounting and data quality assessment of copper products smelted from copper concentrates.

Claims

1. A carbon footprint accounting method for copper products smelted from copper concentrates based on life cycle assessment, characterized in that, It includes: (1) Clearly define the evaluation object Determine whether the product object for carbon footprint accounting is blister copper, anode copper or electrolytic copper; (2) Set the system boundary Define the carbon footprint accounting system boundary according to the product type; The system boundary of blister copper production is the oxygen-enriched smelting system and the converter blowing system; the system boundary of anode copper production is the combination of the oxygen-enriched refining system, the converter blowing system and the anode refining system; the system boundary of electrolytic copper production is the combination of the oxygen-enriched refining system, the converter blowing system, the anode refining system and the electrolytic refining system; (3) Data collection Collect foreground data within the system boundary corresponding to the product and determine the background data source; (4) Establish a life cycle inventory Input the collected data into a table to establish a life cycle inventory; (5) Carbon footprint accounting Establish carbon footprint accounting models for blister copper, anode copper and electrolytic copper products, and combine the collected data to account for the carbon footprint of the products; C 粗铜 = C 火法精炼系统 + C 转炉吹炼系统 C 阳极铜 = C 火法精炼系统 + C 转炉吹炼系统 + C 阳极精炼系统 C 电解铜 = C 火法精炼系统 + C 转炉吹炼系统 + C 阳极精炼系统 + C 电解精炼系统 where C 粗铜 , C 阳极铜 and C 电解铜 are the carbon footprint accounting results of blister copper, anode copper, and electrolytic copper products respectively, and C 富氧熔炼系统 , C 转炉吹炼系统 , C 阳极精炼系统 and C 电解精炼系统 are the carbon emissions of four process steps including the oxygen-enriched smelting system, converter blowing system, anode refining system, and electrolytic refining system respectively.

2. The carbon footprint accounting method for copper products smelted from copper concentrates based on life cycle assessment according to claim 1, characterized in that: The oxygen-enriched smelting system includes oxygen-enriched smelting equipment and separation equipment, the converter blowing system includes a converter, the anode refining system includes an anode refining furnace, and the electrolytic refining system includes an electrolytic refining workshop.

3. The carbon footprint accounting method for copper products smelted from copper concentrate based on life cycle assessment according to claim 1, wherein: The carbon footprint models for the four technological links of the oxygen-enriched refining system, the converter blowing system, the anode refining system and the electrolytic refining system are respectively: EF 富氧熔炼系统,i = ∑EF 富氧熔炼系统,i,j C 富氧熔炼系统 = ∑(EF 富氧熔炼系统,i × Q i ) EF 转炉吹炼系统,i = ∑EF 转炉吹炼系统,i,j C 转炉吹炼系统 = ∑(EF 转炉吹炼系统,i × Q i ) EF 阳极精炼系统,i = ∑EF 阳极精炼系统,i,j C 阳极精炼系统 = ∑(EF 阳极精炼系统,i × Q i ) EF 电解精炼系统,i = ∑EF 电解精炼系统,i,j C 电解精炼系统 = ∑(EF 电解精炼系统,i × Q i ) In the formula, EF represents the actual greenhouse gas emissions, Q is the greenhouse gas emission factor, the subscript i is different types of greenhouse gases, and the subscript j is different source links of greenhouse gases, which are respectively raw material and auxiliary material consumption, energy consumption, fuel consumption and direct emissions.

4. The copper product carbon footprint accounting method based on life cycle assessment according to claim 1, characterized in that: The foreground data includes data on raw material and auxiliary material consumption, energy consumption, fuel consumption and direct emissions in the product system, and the background data preferably uses a localized database that fits the location where the product is produced.

5. A data quality evaluation method, characterized in that, It is used to evaluate the inventory data involved in the carbon footprint accounting of copper concentrate smelting copper products described in any one of claims 1-4, including: Use the pedigree method to evaluate the uncertainty of life cycle inventory data; Use the Monte Carlo simulation method to evaluate the data quality of the carbon footprint accounting results.

6. The data quality evaluation method according to claim 5, wherein: The evaluation method of the life cycle inventory data is as follows: According to the pedigree matrix, corresponding scores are assigned respectively from data reliability, data integrity, index time correlation, regional correlation and technical correlation, and combined with the basic uncertainty of the data, the geometric standard deviation of the inventory data is calculated according to various scores; Wherein, GSD Total is the total geometric standard deviation value for each list data category, GSD R is the geometric standard deviation value of the reliability of the index data, GSD C is the geometric standard deviation value of the integrity of the index data, GSD T is the geometric standard deviation value of the time correlation of the index, GSD G is the geometric standard deviation value of the regional correlation of the index, GSD F is the geometric standard deviation value of the technical correlation of the index, GSD Basic is the basic geometric standard deviation value of the data.

7. The data quality evaluation method according to claim 5, characterized in that: The data quality analysis method of the product carbon footprint accounting results is as follows: Perform Monte Carlo simulation on the inventory data and results, and calculate the coefficient of variation CV according to the simulation results. The calculation formula is as follows: The CV value is used to describe the accuracy of the simulation results. When the CV value is less than 10%, it indicates that the carbon emission accounting data quality is good; when the CV value is between 10% and 20%, it indicates that the carbon emission accounting data quality is average; When the CV value is between 20% and 30%, it indicates that the carbon emission accounting data quality is poor, and sensitivity analysis needs to be carried out and the data accuracy needs to be improved to re-account for the carbon footprint; when the CV value is greater than 30%, it indicates that the carbon emission accounting data quality is extremely poor, and the data source needs to be verified and the carbon footprint needs to be re-accounted.

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