A staged method for blending mineral feedstocks

Abstract

This invention discloses a phased blending method for ore batching, belonging to the field of sinter preparation technology. The method specifically includes the following steps: raw materials are divided into major-grade ore, minor-grade ore, recycled ore, and secondary resources according to the pre-blending plan for the blended ore; the minor-grade ore is added in four stages, as follows: Stage 1: Iron ore powder with low TFe content and high SiO2 content is blended with iron ore powder with high TFe content and low SiO2 content; Stage 2: One type of iron ore powder with high SiO2 content or high TFe content is added; Stage 3: The remaining iron ore powder with high SiO2 content or high TFe content is added; Stage 4: The remaining amounts of each raw material are added; wherein, major-grade ore, recycled ore, and secondary resources are quantitatively added in all four stages of batching. This phased batching method ensures the stability of the chemical composition (TFe, SiO2, etc.) of the blended ore stockpile, with minimal fluctuations in the deviation values ​​of the chemical composition.

Description

Technical Field

[0001] This invention belongs to the field of sinter preparation technology, specifically relating to a staged method for blending and mixing ore. Background Technology

[0002] The blending and heaping of raw material blending ore is the first step in ironmaking. Blending ore is the most important raw material in sinter production, and its compositional stability directly determines the performance of the sinter product. Blending ore is formed by accurately proportioning different types of iron raw materials (fine ore, concentrate, metallurgical by-products, etc.) that meet the requirements of the blast furnace according to a specific ratio, and then continuously and uniformly stacking them to form a large heap of blending ore. Since fluctuations in the SiO2 content of the blending ore during the sintering process affect the basicity (CaO / SiO2) of the sinter, and fluctuations in TFe affect the stability of the iron content in the sinter, supplying blending ore with stable grade and particle size to the sintering machine plays a crucial role in reducing the number of sintering batching tanks, simplifying the sintering batching operation, and stabilizing the quality of the sinter, providing optimal raw material conditions for the long-term stable, high-yield, and high-quality operation of the blast furnace.

[0003] Ore blending refers to the initial mixing of various iron-containing minerals from different sources with significant compositional differences using a batching disc, according to the overall plan for each batch of blended ore. This process ensures the chemical composition of the blended ore remains uniform and stable across all shifts. The goal is to keep the composition of the blended ore within a certain range for each shift, minimizing the variance in chemical composition between shifts to meet the requirements of subsequent sintering and ironmaking processes, thus arriving at the final batching scheme. The most crucial aspect of blending is determining the types of materials in the batching bins and their feeding sequence. However, the iron-containing minerals to be blended in the stockyard are diverse, with significant differences in mineral composition. Furthermore, the limited number of batching bins and the restricted feeding volume of the batching disc make it extremely difficult to ensure uniform and stable chemical composition in the blended ore for each shift. Only by calculating the proportions accurately and promptly during the blending process can the chemical composition of TFe, SiO2, and other components in the blended ore be better stabilized, meeting subsequent production requirements and effectively serving sintering and blast furnace operations. Therefore, it is urgent to provide a staged blending method for ore batching, which involves batching in stages to ensure the stability of the chemical composition in the blended ore. Summary of the Invention

[0004] In view of the shortcomings of the prior art, one of the objectives of this invention is to provide a staged blending method for ore batching, which can ensure the stability of chemical components such as TFe and SiO2 in the blended ore.

[0005] To achieve the above objectives, the specific technical solution of the present invention is as follows:

[0006] A staged method for blending and batching minerals, the method specifically includes the following steps:

[0007] According to the pre-mixing plan of the blended ore, the raw materials are divided into major varieties of ore, minor varieties of ore, return ore and secondary resources;

[0008] The minor mineral varieties will be blended in four stages, as detailed below:

[0009] The first stage involves mixing iron ore powder with low TFe content and high SiO2 content with iron ore powder with high TFe content and low SiO2 content.

[0010] Second stage: Add one type of iron ore powder with high SiO2 content or high TFe content;

[0011] The third stage: Add the remaining iron ore powder with high SiO2 content or high TFe content;

[0012] Fourth stage: Add the remaining amounts of each raw material;

[0013] Among them, large-variety ores, recycled ores, and secondary resources are all quantitatively added in all four stages of the batching process.

[0014] The batching method of this invention introduces unstable minor minerals in four stages, which can ensure the stability of chemical components such as TFe and SiO2 in the mixed ore pile, and the deviation range of chemical components is small. This solves the problems of unstable minor mineral composition, limited number of batching bins, and limited material discharge from batching discs, and obtains a mixed ore pile with stable composition.

[0015] Preferably, after classifying the raw materials, the secondary resources are mixed and placed in a warehouse.

[0016] Preferably, the batching time for the first stage is 42% to 60% of the total batching time for the bulk batch, the batching time for the second stage is 14% to 30% of the total batching time for the bulk batch, the batching time for the third stage is 7% to 25% of the total batching time for the bulk batch, and the batching time for the fourth stage is 7% to 25% of the total batching time for the bulk batch.

[0017] Preferably, the total batching time for the blended ore pile is 70 hours, with the first stage batching time being 36 hours, the second stage batching time being 15 hours, the third stage batching time being 9 hours, and the fourth stage batching time being 10 hours.

[0018] Preferably, the amount of each iron ore powder to be added is calculated by calculation method before batching, so as to obtain the final mixed ore pile, so that the content of TFe and SiO2 in the final mixed ore pile meets the requirements of TFe content and SiO2 content in the pre-batching plan.

[0019] Preferably, the major ore variety is iron ore powder with a dry content of 10% or more in the blended ore; the minor ore variety is iron ore powder with a dry content of less than 10% in the blended ore.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] The batching method of this invention introduces unstable minor minerals in four stages, which can ensure the stability of chemical components such as TFe and SiO2 in the mixed ore pile, and the deviation range of chemical components is small. This solves the problems of unstable minor mineral composition, limited number of batching bins, and limited material discharge from batching discs, and obtains a mixed ore pile with stable composition. Detailed Implementation

[0022] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1

[0024] Taking the pre-mixed feedstock #25 as an example, the pre-mixing scheme for the blended ore is shown in Table 1.

[0025] Table 1. Pre-mixing scheme for No. 25 blended ore (%)

[0026]

[0027]

[0028] The wet weight of each iron ore powder is calculated based on the dry weight and H2O content. The calculation formula is as follows: wet weight = dry weight / (1 - moisture percentage); for example, the wet weight of PB powder = 15400 / (1 - 0.0932) = 16983. The wet weight of each iron ore powder is calculated based on the above formula. The wet weight of each iron ore powder in the pre-mixed feed of No. 25 pile is shown in Table 2.

[0029] Table 2. Wet content (tons) of pre-mixed feedstock #25

[0030]

[0031]

[0032] As shown in Table 2, the total wet weight of the premixed stockpile is 75,521 tons. Considering that the actual situation may be slightly different (moisture, secondary resources and return ore factors), the total wet weight of the large stockpile will eventually be around 76,000 tons. According to the standard load of the conveyor belt of 1,100 tons / hour, the total time to complete the mixing of the large stockpile is 70 hours.

[0033] The premixed feedstock contains four major ore varieties (PB powder, BRBF powder, FMG mixed powder, and direct-supply iron concentrate), four minor ore varieties (Mauritanian powder, domestic iron concentrate, Lao powder, and South African powder), five secondary resources (ironmaking gas ash, iron oxide scale, dust collector ash, sludge, and steel slag magnetic separation powder), and two return ore varieties (blast furnace return ore and lump ore return ore). The main elements TFe and SiO2 in the blended feedstock are 60.39% and 4.99%, respectively.

[0034] The five secondary resources (iron smelting gas ash, iron oxide scale, dust removal ash, sludge, and steel slag magnetic separation powder) are mixed and added to a secondary resource silo.

[0035] The next step involves preparing the ingredients in four stages:

[0036] Phase 1: Analysis of the pre-mixing plan revealed significant differences in the composition of minor ore varieties, indicating instability and necessitating separate addition. However, this increases the number of batching silos, potentially leading to a lack of spare silos and increased risk. Mauritanian powder, with its low TFe and high SiO2 content, can be mixed with South African powder, which has relatively high TFe and low SiO2. This determines the material types for Phase 1. Further analysis using the actual batching data, considering the total moisture content of the minor ore varieties and the batching time, calculates the required quantity of each ore variety. Phase 1 is then completed, requiring 36 hours of batching time. The calculated TFe content in the blended ore after Phase 1 is 60.51%, and the SiO2 content is 5.08%, within ±0.2% of the TFe and SiO2 content in the pre-mixing plan.

[0037] Second stage: Two minor ore varieties remain to be added. Lao iron powder and domestic iron concentrate have similar compositions, with both having high SiO2 content. They can be added at different stages. Based on the actual performance table of the batching, the Lao iron powder will be added in the second stage, requiring 15 hours of batching time. After completing the second stage of batching, the TFe content in the mixed ore will be 60.47 and the SiO2 content will be 4.86.

[0038] The third stage: The last small-variety ore (domestic iron concentrate) is added in the third stage. After deduction, it was found that adding all of the domestic iron concentrate would result in an excessively high TFe content. Therefore, only a portion (1080 tons) is added in the third stage. The required batching time is 9 hours. The deduced TFe content of the mixed ore is 60.52 and the SiO2 content is 4.87.

[0039] The fourth stage involves integrating and extrapolating the remaining quantities of each material type. If the calculated composition fluctuations exceed the acceptable range, the previous stages are fine-tuned until the composition fluctuations in each stage are minimized. After all stages are completed, the final TFe content in the blended ore heap is calculated to be 60.45% and the SiO2 content to be 4.96%, which is basically consistent with the TFe and SiO2 contents in the pre-mixing plan.

[0040] To ensure the stability of the mixed ore composition, four major ore varieties, two return ore varieties, and five secondary resources are quantitatively added in all four stages of the entire process.

[0041] The batching performance table is used to calculate the content of the main elements TFe and SiO2 in the blended ore pile, and to deduce the amount of each iron ore powder to be added when the cumulative content of TFe and SiO2 in the blended ore pile meets the pre-batching plan.

[0042] The specific calculation method is as follows:

[0043] TFe content per class = (Dry weight of single-variety ore A * TFe content of A + Dry weight of single-variety ore B * TFe content of B + ...) / Dry weight per class;

[0044] SiO2 content of a class = (dry weight of single-variety ore A * SiO2 content of A + dry weight of single-variety ore B * SiO2 content of B + ...) / dry weight of a class;

[0045] In the above formula, A and B each refer to a certain type of iron ore powder in 1.

[0046] By analogy, the content of each element in each shift can be calculated, and then the cumulative amount of the mixed ore pile can be calculated.

[0047] Total TFe content of the bulk pile = (Total dry weight of the bulk pile during the workday * Total TFe content of the workday + Dry weight of this shift * TFe content of this shift) / Total dry weight of this shift;

[0048] The cumulative SiO2 content of the bulk pile = (the cumulative dry weight of the bulk pile during the shift * the cumulative SiO2 content during the shift + the dry weight of this shift * the SiO2 content of this shift) / the cumulative dry weight of this shift;

[0049] Similarly, once the batches are fully prepared, the total amount of ingredients can also be calculated.

[0050] The phased ingredient plan allows you to input the pre-planned ingredients into this table, calculate the content of each element, thereby verifying the feasibility of the plan and ensuring the consistency of each element content with the pre-planned ingredients.

[0051] The deduction shows that the batching situation of each stage of the mixing and batching method of this embodiment is shown in Table 3.

[0052] Table 3. Time-based breakdown of batching capacity for 23AD25# bulk pile

[0053]

[0054]

[0055] Note: Because the arrival time and quantity of various secondary resources in the blended ore heap are not fixed, it is necessary to communicate with the feeding unit in advance before each batch of blended ore heap to know the arrival time and quantity of each batch, and then formulate the specific batching quantity. Therefore, there may be situations where the batching quantity in the same warehouse is different.

[0056] The phased blending and batching method of the present invention saves the time spent on batching calculations per shift, ensures that the error of the chemical composition of the blended ore is as small as possible per shift, and makes the fluctuation range of the deviation value of the chemical composition in the large pile of blended ore small and the accuracy high.

[0057] The standard deviations of TFe and SiO2 in the mixed ore in May of different years (2021, 2022, and 2023) were compared:

[0058] Table 4 Standard deviations of TFe and SiO2 in May 2021 (without using the staged batching method)

[0059] index 25# pile 26# pile 27# pile 28# pile 29# pile 30# pile 31# pile average value TFe 0.11 0.12 0.12 0.14 0.17 0.19 0.19 0.16 <![CDATA[SiO2]]> 0.09 0.10 0.12 0.15 0.09 0.15 0.16 0.12

[0060] Table 5 Standard deviations of TFe and SiO2 in May 2022 (without using the staged batching method)

[0061] index 29# pile 30# pile 31# pile 32# pile 33# pile 34# pile 35# pile average value TFe 0.12 0.13 0.15 0.19 0.14 0.12 0.13 0.15 <![CDATA[SiO2]]> 0.11 0.11 0.14 0.12 0.12 0.12 0.11 0.12

[0062] Table 6 Standard Deviation of TFe and SiO2 in May 2023 (using a phased batching method)

[0063] index 27# pile 28# pile 29# pile 30# pile 31# pile 32# pile 33# pile average value TFe 0.14 0.13 0.10 0.15 0.13 0.14 0.14 0.13 <![CDATA[SiO2]]> 0.11 0.09 0.11 0.09 0.10 0.12 0.12 0.11

[0064] As can be seen from the data in Tables 4-6, after the phased batching method was used in 2023, the standard deviation of the main elements in the blended ore pile was significantly improved compared with 2021. Among them, the average value of TFe decreased by 0.03 and the average value of SiO2 decreased by 0.01.

[0065] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A staged method for blending and mixing mineral feedstocks, characterized in that, The ingredient preparation method specifically includes the following steps: According to the pre-mixing plan of the blended ore, the raw materials are divided into major varieties of ore, minor varieties of ore, return ore and secondary resources; The minor mineral varieties will be blended in four stages, as detailed below: The first stage involves mixing iron ore powder with low TFe content and high SiO2 content with iron ore powder with high TFe content and low SiO2 content. Second stage: Add one type of iron ore powder with high SiO2 content or high TFe content; The third stage: Add the remaining iron ore powder with high SiO2 content or high TFe content; Fourth stage: Add the remaining amounts of each raw material; Among them, large-variety ores, recycled ores, and secondary resources are all quantitatively added in all four stages of the batching process; The first stage of batching takes 42% to 60% of the total batching time, the second stage takes 14% to 30% of the total batching time, the third stage takes 7% to 25% of the total batching time, and the fourth stage takes 7% to 25% of the total batching time. The major grade ore is iron ore powder with a dry content of 10% or more in the blended ore; the minor grade ore is iron ore powder with a dry content of less than 10% in the blended ore.

2. The staged mixing and batching method for mineral feedstocks according to claim 1, characterized in that, After classifying the raw materials, the secondary resources are mixed and placed in a warehouse.

3. The staged mixing and batching method for mineral feedstocks according to claim 1, characterized in that, The total batching time for the blended ore stockpile is 70 hours. The batching time for the first stage is 36 hours, the batching time for the second stage is 15 hours, the batching time for the third stage is 9 hours, and the batching time for the fourth stage is 10 hours.

4. The staged mixing and batching method for mineral feedstocks according to claim 1, characterized in that, Before batching, the amount of each iron ore powder to be added is calculated to obtain the final blended ore pile, so that the content of TFe and SiO2 in the final blended ore pile meets the requirements of TFe and SiO2 content in the pre-batching plan.

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