Energy-saving smelting process method of carbon ferromanganese

Abstract

The application discloses an energy-saving smelting process method of carbon ferromanganese, and relates to the technical field of metallurgy. The method comprises the following steps: after the types of manganese ore raw materials are determined, the chemical component content of each manganese ore raw material is determined respectively, and the required amount of each manganese ore raw material is calculated according to the principle that the natural alkalinity (CaO+MgO) / SiO2 of the limited charging raw material is 0.7-0.75; the amount of the reducing agent coke is calculated according to the principle that the ratio C / Mn of the fixed carbon of the comprehensive component of the charging coke and the comprehensive manganese of the charging is 0.38-0.41; the above-mentioned manganese ore raw materials and the reducing agent coke are proportioned and added into a smelting furnace; and the primary distribution power voltage of the power supply system of the smelting furnace is adjusted to 38-39.5 ten thousand volts, and the secondary distribution power voltage level is adjusted to 100-125 volts. The application can prolong the service life of the furnace lining, improve the manganese element recovery rate of the carbon ferromanganese, reduce the smelting cost, and create higher economic benefits.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, and in particular to an energy-saving smelting process for carbon manganese ferromanganese. Background Technology

[0002] The production of carbon ferromanganese in electric arc furnaces, whether using the flux-less or flux-free method, involves the use of carbon-deficient operating processes (such as... Figure 1 As shown, this production method selectively reduces most of the manganese into the alloy and silicon into the slag. The main raw materials are various manganese ores, with a small amount or no dolomite or lime added as a slag-forming agent. Coke is used as a reducing agent, and a reduction reaction occurs in a submerged arc furnace to obtain carbon ferromanganese, composed of manganese, silicon, iron, and carbon. Due to the carbon-deficient operation, some unreduced manganese and most of the silicon enter the slag, producing a manganese-rich slag with a manganese content of approximately 30% and a (CaO+MgO) / SiO2 ratio between 0.3 and 0.5. The carbon ferromanganese is sold directly, while the manganese-rich slag is crushed and processed into suitable particle sizes to be used as raw material in the furnace to produce manganese-silicon alloys.

[0003] The production of carbon ferromanganese using a carbon-deficient process has the following disadvantages: 1) Due to the carbon-deficient operation, there is insufficient reducing agent in the high-temperature reaction zone of the furnace. Under the high-temperature conditions inside the furnace, the carbonaceous lining of the submerged arc furnace is oxidized and eroded by the slag. The carbon ferromanganese produced by the carbon-deficient operation is an unsaturated carbon melt, which dissolves the carbon elements in the carbonaceous lining inside the furnace, causing continuous erosion of the lining. The carbon-deficient operation produces a large amount of acidic slag, which has a particularly severe erosion effect on the lining. The carbon-deficient process for producing carbon ferromanganese will cause severe erosion of the lining and furnace bore in a short period of time, and the lining life is often only about six months. In some cases, even new linings burn through the furnace bottom within a month of producing carbon ferromanganese. 2) Due to the carbon-deficient operation, the manganese recovery rate is only about 75%, producing a large amount of acidic manganese-rich slag. The slag-to-iron ratio is usually 0.85-0.9:1. The price of manganese alloy per ton and the price of manganese in the slag differ greatly (60-70 yuan / ton). The large amount of slag and the low alloy content increase the company's costs. 3) The lack of carbon results in a large amount of slag, high power consumption, low manganese recovery rate, low unit output of the furnace, and low production efficiency, leading to high production costs and seriously affecting the company's profitability. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems existing in the production of carbon ferromanganese using existing carbon-deficient processes, and to provide a novel carbon-sufficient production process—an energy-saving smelting process for carbon ferromanganese. This smelting process extends the service life of the furnace lining, improves the recovery rate of manganese in carbon ferromanganese, reduces smelting costs, and creates higher economic benefits.

[0005] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0006] It includes the following steps:

[0007] (a) Preparation of raw manganese ore: After determining the type of each raw manganese ore, the chemical composition content of each raw manganese ore is determined, and the required amount of each raw manganese ore is calculated according to the principle that the natural alkalinity (CaO+MgO) / SiO2 of the raw material entering the furnace is limited to 0.7 to 0.75.

[0008] (II) Preparation of reducing agent coke: After determining the type and amount of each raw material manganese ore, the amount of reducing agent coke is calculated according to the principle that the ratio of fixed carbon in coke to total manganese in the furnace is limited to 0.38 to 0.41.

[0009] (III) Batching: The above-mentioned raw materials, manganese ore and reducing agent coke, are batched and added to the smelting furnace;

[0010] (iv) Power supply for smelting: Adjust the distribution voltage of the power supply system for the smelting furnace, adjusting the primary distribution voltage to 38,000 kV to 39,500 kV and the secondary distribution voltage to 100 V to 125 V.

[0011] A more specific technical solution to the above technical solution could be: when determining the types of manganese ore used, reduce the amount of ore with high SiO2 content and increase the amount of ore with high CaO and MgO content.

[0012] Furthermore, the ore with high SiO2 content refers to ore with SiO2 content higher than 9.5%.

[0013] Furthermore, the ore with high CaO and MgO content refers to ore with a total CaO and MgO content of 5% to 6.5%.

[0014] Furthermore, the reducing agent coke is a combined reducing agent formed by combining coke with a particle size of 5 mm to 15 mm and coke with a particle size of 10 mm to 30 mm.

[0015] Furthermore, in the combined reducing agent, coke with a particle size of 5mm to 15mm is used as the mainstream coke.

[0016] Furthermore, the mainstream coke accounts for 60% to 70% of the mass of the combined reducing agent.

[0017] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0018] 1. This invention summarizes the effective control range of the natural basicity (CaO+MgO) / SiO2 and C / Mn parameters of the raw materials fed into the furnace, and organizes the production of carbon ferromanganese using the carbon-sufficient method to achieve the goals of increasing slag basicity, reducing slag ratio, increasing recovery rate, reducing smelting power consumption, extending furnace lining service life, and improving production efficiency and profit.

[0019] 2. This invention first optimizes the blending of manganese ore fed into the furnace, increasing the useful components and optimizing the composition structure. It reduces the amount of ore with high SiO2 content and increases the blending of ores with high CaO and MgO content. This eliminates the need to adjust the composition and basicity of the slag without using any flux (auxiliaries or slagging agents). The invention also ensures sufficient coke for the reduction of carbon ferromanganese is produced according to the coke balance calculation, thereby reducing the amount of slag and lowering the slag-to-iron ratio to 0.55–0.6:1. Secondly, it adjusts the primary voltage and selects an appropriate secondary voltage level to effectively increase the power output. Ultimately, this ensures increased manganese recovery rate, increased output, and reduced power consumption, thus lowering the production cost of carbon ferromanganese.

[0020] 3. Through multiple verifications, this invention has found that when the natural basicity (CaO+MgO) / SiO2 of the raw material entering the furnace reaches 0.7 to 0.75 and the C / Mn (the ratio of fixed carbon in coke to total manganese in the furnace) reaches 0.38 to 0.41, the carbon-sufficient method for producing carbon manganese ferromanganese can be realized.

[0021] 4. This invention, by incorporating the control range of C / Mn parameters, uses a reducing agent in conjunction with the process, without the addition of flux. Appropriately increasing the reducing agent achieves the production of carbon ferromanganese using the full carbon method, enriching the Al2O3 content in the slag to between 12.5% ​​and 13%. This reduces the slag ratio to 0.55–0.60, increases the manganese content in the slag to 24%–26%, and raises the slag basicity from 0.3–0.5 to 0.6–0.7. Consequently, the manganese recovery rate increases from below 75% to above 79%, achieving the goals of reduced slag volume, increased output, reduced power consumption, and reduced costs.

[0022] 5. This invention, taking into account the characteristics of the submerged arc furnace, selects low-priced, small-particle-size 5mm-15mm coke as the mainstream coke (to promote reduction) and mixes it with high-quality 10mm-30mm coke (to facilitate electrical conductivity and sufficient load) in a certain proportion to form a combined reducing agent for the production of carbon ferromanganese. This can effectively increase the contact surface of the carbonaceous reducing agent in the submerged arc furnace, enhance the reduction of useful elements, and effectively reduce the reducing agent procurement cost for carbon ferromanganese production enterprises. Attached Figure Description

[0023] Figure 1 A flowchart for producing carbon ferromanganese using existing carbon-deficient operating processes. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to embodiments: Example

[0025] It includes the following steps:

[0026] (a) Preparation of raw manganese ore: After determining the type of raw manganese ore, the chemical composition content of each raw manganese ore is measured. Based on the principle that the natural alkalinity (CaO+MgO) / SiO2 of the raw material entering the furnace is limited to 0.7 to 0.75, the required amount of each raw manganese ore is calculated and filled into Table 1 below.

[0027] Table 1

[0028] .

[0029] In Table 1, the SiO2 content of manganese ore 1 is 12.42, and the total CaO+MgO content is 1.48.

[0030] The SiO2 content of manganese ore 2 is 4.69, and the total CaO+MgO content is 5.05.

[0031] The SiO2 content of manganese ore 3 is 4.90, and the total CaO+MgO content is 14.65.

[0032] Natural basicity (CaO+MgO) / SiO2 = (1.48×340+5.05×500+14.65×160) / (12.42×340+4.69×500+4.90×160) = 0.7307. It can be seen that the natural basicity (CaO+MgO) / SiO2 value is in the range of 0.7 to 0.75, which meets the process requirements for producing carbon ferromanganese without flux and with a low slag ratio (i.e., full carbon method).

[0033] (ii) Preparation of reducing agent coke: After determining the type and amount of each raw material manganese ore, according to the principle that the ratio of fixed carbon in coke to total manganese in the furnace is limited to 0.38 to 0.41, the amount of reducing agent coke is calculated and filled in Table 2 below.

[0034] Table 2

[0035] .

[0036] In Table 2, among the reducing agent coke, coke with a particle size of 5 mm to 15 mm is the mainstream coke, accounting for 66.67% by mass; coke with a particle size of 10 mm to 30 mm is the mainstream coke, accounting for 33.33% by mass.

[0037] The ratio of fixed carbon in coke to total manganese in the furnace, C / Mn, is calculated as follows: C / Mn = [150 × 85.56 × (100% - 10.7%) + 75 × 83.59 × (100% - 8.5%)] / (42.83 × 1000) = 0.4015. Therefore, the C / Mn ratio is within the range of 0.38 to 0.41, which meets the process requirements for producing carbon ferromanganese using the full-carbon method.

[0038] (III) Batching: The above-mentioned raw materials, manganese ore and reducing agent coke, are batched and added to the smelting furnace.

[0039] (iv) Power supply for smelting: As shown in Table 3, adjust the distribution voltage of the power supply system for the smelting furnace, adjust the primary distribution voltage to 38,000 kV to 39,500 kV, and adjust the secondary distribution voltage level to 100 V to 125 V.

[0040] Table 3

[0041] .

[0042] (v) Slag ingot molds, iron ingot molds, and sampling and analysis:

[0043] During the tapping process, samples of the product carbon manganese ferroalloy and slag were taken for chemical analysis. The same batch of raw manganese ore was used to prepare carbon manganese ferroalloy and determine the chemical composition of slag multiple times. The chemical composition of the product carbon manganese ferroalloy is shown in Table 4 below, the chemical composition of the slag is shown in Table 5 below, and the relevant indicators of the product carbon manganese ferroalloy are shown in Table 4 below.

[0044] Table 4

[0045] .

[0046] Table 5

[0047] .

[0048] Table 6

[0049] .

[0050] Note: In Table 6, "before improvement" refers to the background technology. Figure 1 The carbon-deficient operating process shown, "after improvement" refers to the carbon-sufficient production process of the present invention (i.e., the embodiment).

[0051] Furthermore, during the trial production of carbon manganese ferromanganese using the full-carbon method in furnaces 105#-107# of the company from September to December 2022, the applicant of this invention demonstrated significant advantages in the following indicators: smelting power consumption was 2345 kWh, a decrease of 99 kWh compared to the average power consumption of 2444 kWh for carbon manganese ferromanganese from January to August 2022; average daily output increased by 2.2 tons; ore consumption decreased by 161 kg / t; coke consumption decreased by 16 kg / t; and the slag-to-iron ratio decreased from approximately 0.85-0.9 to below 0.6. The recovery rate of metallic manganese increased by 4.81% (from 75.12% to 79.93%).

[0052] Following the successful application of this technology in carbon ferromanganese production from January to March 2023, various technical and economic indicators have been further improved. Specifically, smelting power consumption was 2334 kWh / t, a decrease of 110 kWh / t compared to the previous year (January-August 2022). Manganese ore consumption decreased by 169 kg / t, average daily output increased by 3.91 tons, and coke consumption decreased by 7 kg / t. Manganese recovery rate increased by 4.86%, with the recovery rate of metallic manganese at each furnace consistently above 79.5%, and excellent furnaces achieving a recovery rate of 82%.

[0053] Therefore, it can be seen that the technical solution of the present invention has the following effects:

[0054] I. Significantly improve economic and technical indicators:

[0055] (1) After the implementation of the carbon-based process for producing carbon ferromanganese, the slag-to-iron ratio decreased from 0.85-0.9 to 0.55-0.6, the amount of slag was significantly reduced, and the manganese recovery rate increased from 75% to 79.98%.

[0056] (2) After the implementation of the carbon-based method for producing carbon manganese ferromanganese, the consumption of manganese ore per ton of iron ore has decreased. The consumption of manganese ore has decreased from the original 2263 kg / t to the current 2094 kg / t (cumulative from January to March 2023), a decrease of 7.47%.

[0057] (3) After the implementation of the carbon-based process for producing carbon ferromanganese, the amount of slag is reduced, the loss of electricity and heat is reduced, and the power consumption is significantly reduced: the power consumption index for smelting carbon ferromanganese has decreased from 2444 kWh / t to 2334 kWh / t (cumulative from January to March 2023), a decrease of 4.5%;

[0058] (4) The carbon-saturated process for producing carbon ferromanganese can reduce the erosion of the furnace lining by slag and iron, increasing the furnace service life from the original 10 months to the current ≥24 months, effectively reducing the cost per ton of carbon ferromanganese. At the same time, it eliminates the occurrence of abnormal molten metal overflow accidents caused by furnace lining burn-through;

[0059] II. Significant social benefits: It promotes the advancement of ferroalloy smelting technology and effectively advances energy conservation and emission reduction efforts;

[0060] III. Good ecological benefits: Reduces the use of resources such as manganese ore, dolomite, and lime, reduces the generation of carbon manganese iron slag, and reduces environmental pressure.

[0061] It should be noted that the above embodiments are used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An energy-saving smelting process for carbon manganese ferromanganese, characterized in that... Includes the following steps: (a) Preparation of raw manganese ore: After determining the type of each raw manganese ore, the chemical composition content of each raw manganese ore is determined, and the required amount of each raw manganese ore is calculated according to the principle that the natural alkalinity (CaO+MgO) / SiO2 of the raw material entering the furnace is limited to 0.7 to 0.

75. (II) Preparation of reducing agent coke: After determining the type and amount of each raw material manganese ore, the amount of reducing agent coke is calculated according to the principle that the ratio of fixed carbon in coke to total manganese in the furnace is limited to 0.38 to 0.

41. (III) Batching: The above-mentioned raw materials, manganese ore and reducing agent coke, are batched and added to the smelting furnace; (iv) Power supply for smelting: Adjust the distribution voltage of the power supply system for the smelting furnace, adjusting the primary distribution voltage to 38,000 kV to 39,500 kV and the secondary distribution voltage to 100 V to 125 V.

2. The energy-saving smelting process for carbon manganese ferrocarbon according to claim 1, characterized in that: When determining the types of manganese ore used, reduce the amount of ore with high SiO2 content and increase the amount of ore with high CaO and MgO content.

3. The energy-saving smelting process for carbon manganese ferrocarbon according to claim 2, characterized in that: The term "high SiO2 content ore" refers to ore with a SiO2 content higher than 9.5%.

4. The energy-saving smelting process for carbon manganese ferrocarbon according to claim 3, characterized in that: The ore with high CaO and MgO content refers to ore with a total CaO and MgO content of 5% to 6.5%.

5. The energy-saving smelting process for carbon manganese ferrocarbon according to claim 4, characterized in that: The reducing agent coke is a combined reducing agent formed by combining coke with a particle size of 5 mm to 15 mm and coke with a particle size of 10 mm to 30 mm.

6. The energy-saving smelting process for carbon manganese ferrocarbon according to claim 5, characterized in that: In the combined reducing agent, coke with a particle size of 5mm to 15mm is the mainstream coke.

7. The energy-saving smelting process for carbon manganese ferrocarbon according to claim 6, characterized in that: The mainstream coke accounts for 60% to 70% of the mass of the combined reducing agent.

Images