Production process of low-nickel molten iron added with medium nickel ore
By using low-aluminum laterite nickel ore and combining medium-nickel ore in the low-nickel molten production process, and combining the sintering process and blast furnace smelting process, the problem of high production costs of medium- and low-nickel molten in the existing technology is solved, and the effect of reducing production costs and increasing output is achieved.
Patent Information
- Application Number
- CN202411540512.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2025-03-04
AI Technical Summary
In the existing low-nickel molten production process, the market price of low-aluminum laterite nickel ore is relatively high, resulting in high production costs. How to produce high-quality low-nickel molten and stainless steel products at low cost is a difficult problem.
The process of using low-aluminum laterite nickel ore and medium-nickel ore is used to prepare sintered ore through the sintering process. The nickel content of medium-nickel ore is higher than that of low-aluminum laterite nickel ore and the iron content is lower than that of it. The iron content is added to supplement the iron content and reduce the cost of raw materials.
It effectively reduces the raw material cost of low-nickel molten iron production, improves the output and quality of sintered ore, reduces the iron block ore allocation ratio during blast furnace smelting, and reduces the overall production cost.
Smart Images
Figure SMS_1 
Figure SMS_2 
Figure SMS_3
Abstract
Description
Technical Field
[0001] The invention relates to the field of stainless steel manufacturing, and in particular to a production process of low-nickel molten iron with added medium nickel ore. Background Art
[0002] In stainless steel production, low-nickel molten iron is the first step in stainless steel production. At present, low-nickel molten iron is produced by first sending low-aluminum laterite nickel ore to a sintering machine for sintering into blocks (i.e., sintering process) to obtain sintered ore; then, the sintered ore is loaded into a blast furnace together with coke, etc., and oxidized and reduced under high temperature conditions (i.e., blast furnace smelting process) to obtain slag. The current market price of low-aluminum laterite nickel ore is US$36.5 / ton. Due to the high production cost of existing low-nickel molten iron. How to produce high-quality low-nickel molten iron and stainless steel products at the lowest production cost is the goal that every stainless steel manufacturer constantly pursues.
[0003] Nickel ore is an important mineral resource, usually used to extract raw materials for nickel metal. Nickel metal is widely used in modern industry, for example, in the manufacture of steel alloys, batteries, etc. Generally speaking, nickel ore with an iron content of less than 10% can be called high-grade nickel ore. At present, high-grade nickel ore is usually smelted in a submerged arc furnace or a converter to produce high-nickel molten iron containing more than 10% nickel, which is used to produce high-purity nickel metal.
[0004] During the mining process of high-nickel ore, medium-nickel ore (nickel content is usually 1.2-1.6%, iron content is usually 28-45%) will be associated. The current market price of medium-nickel ore is US$26.5 / ton, which is much lower than the market price of low-alumina laterite nickel ore. However, if this type of medium-nickel ore is used for reduction production in a blast furnace, due to its low iron content, it is impossible to obtain sintered ore that meets the iron content requirements (the iron content of the sintered ore is too low). When smelting such sintered ore in a blast furnace, the slag volume is large and the nickel content is high. The blast furnace reduction temperature (the blast furnace temperature can reach up to 1450°C) is not enough, making production difficult, which will cause costs to rise instead of fall.
[0005] Therefore, how to use the lower-priced medium-nickel ore in a benign manner in the blast furnace for low-nickel iron water smelting, and truly reduce the production cost of low-nickel iron water and increase the output of low-nickel iron water while ensuring the quality of low-nickel iron water, is a research direction worth exploring. Summary of the invention
[0006] The purpose of the present invention is to provide a production process of low-nickel molten iron by adding medium nickel ore.
[0007] The technical scheme for achieving the purpose of the present invention is: a production process of low-nickel molten iron with medium nickel ore, including a sintering process; The raw materials of the sintering process include low-aluminum laterite nickel ore, medium nickel ore and iron oxide scale; The medium nickel ore is a type of nickel ore with a Ni content of 1.2-1.6% and a TFe content of 28-45%. The Ni content of the medium nickel ore is higher than that of the low-aluminum laterite nickel ore, and the TFe content is lower than that of the low-aluminum laterite nickel ore. Moreover, the difference in TFe content between the medium nickel ore and the low-aluminum laterite nickel ore is greater than the difference in Ni content. The total addition ratio of the low-aluminum laterite nickel ore and the medium nickel ore is limited to a Ni content of 0.8-0.85% in the sintered ore obtained after sintering. The iron oxide scale is a byproduct produced in the production of steelmaking and rolling. The iron oxide scale is used as a TFe supplement. The amount of the iron oxide scale added is limited to a TFe content of 48-50% in the sintered ore obtained after sintering. The sintered ore for low-nickel iron water production is obtained through the sintering process.
[0008] The inventor uses laterite nickel ore and medium nickel ore to produce low-nickel molten iron for the first time. Since the current price of medium nickel ore (26.5 US dollars / ton) is much lower than the price of low-aluminum laterite nickel ore (36.5 US dollars / ton), the addition of medium nickel ore can replace part of the laterite nickel ore, so that the cost of raw materials is reduced; the lower the nickel content in the low-aluminum laterite nickel ore used, the more medium nickel ore is added, and the lower the cost. When producing low-nickel molten iron for 201 stainless steel, according to the low-aluminum laterite nickel ore currently available on the market, the invention can add medium nickel ore up to 20%. In addition, when the laterite nickel ore and the medium nickel ore are mixed, the problem of insufficient TFe content will occur. The invention supplements the TFe content by adding iron scale produced as a byproduct in steelmaking and rolling production. The cost of iron scale is zero, avoiding the increase of cost. In addition, since the nickel content of the medium nickel ore is relatively high, it is conducive to obtaining sintered ore with a higher nickel content, thereby providing favorable conditions for adding more low-cost ores such as iron nuggets to the sintered ore during blast furnace smelting.
[0009] The raw materials for the sintering process also include quicklime (CaO), and the CaO is used as an alkalinity regulator. The amount of CaO added is limited to control the alkalinity CaO / SiO2 in the sintered ore to be 0.9-1.5.
[0010] The raw materials of the sintering process also include serpentine, which is used as a supplement for MgO and SiO2. The amount of serpentine added is limited to SiO2>6.0% and MgO>3.0% in the sintered ore. Furthermore, the MgO and / or SiO2 content of the medium nickel ore is higher than that of the low-aluminum laterite nickel ore. Compared with the existing process of producing low-nickel molten iron with simple low-aluminum laterite nickel ore (without adding medium nickel ore), the raw material composition of low-aluminum laterite nickel ore added with medium nickel ore adopted in the present invention can increase the silicon content of the sintered ore, which is beneficial to the formation of liquid phases such as calcium ferrite and iron olivine, and is beneficial to increase the temperature of the sintering machine during production and accelerate the pre-reduction of the sintered ore, and the fuel consumption can be reduced; at the same time, more quicklime needs to be added to obtain the same sintered ore basicity. Quicklime is used as a binder, which makes the balling more ideal during the sintering batching process, thereby facilitating the increase of the output of the sintering machine to achieve the goal of increasing production. In a specific implementation process, the amount of serpentine added is preferably 0, and the amount of serpentine added is reduced to a minimum.
[0011] Furthermore, the low-aluminum laterite nickel ore can be replaced by a composition obtained by adding low-aluminum laterite ore to high-aluminum laterite nickel ore in proportion.
[0012] Furthermore, a blast furnace smelting process is performed after the sintering process; the raw materials of the blast furnace smelting process include iron block ore and sintered ore obtained by the sintering process, and blast furnace molten iron, i.e., the low-nickel molten iron, is obtained by blast furnace reduction smelting. Since the nickel content of the sintering raw materials can be increased according to the increase in the amount of the added medium nickel ore after the medium nickel ore is added to the sintering raw materials, the nickel content of the sintered ore can be increased, and the increase in the nickel content of the sintered ore increases the proportion of iron block ore added in the blast furnace smelting process when preparing low-nickel molten iron with the same nickel content, and decreases the proportion of sintered ore added. Since the iron block ore has low cost and is easy to reduce, the cost can be reduced while the output can be increased. DETAILED DESCRIPTION
[0013] The following is a detailed description of a preferred embodiment of a process for producing low-nickel molten iron with medium nickel ore according to the present invention.
[0014] A process for producing low-nickel molten iron with medium nickel ore, comprising a sintering process; The raw materials of the sintering process include low-aluminum laterite nickel ore, medium nickel ore and iron oxide scale; The medium nickel ore is a type of nickel ore with a Ni content of 1.2-1.6% and a TFe content of 28-45%. The Ni content of the medium nickel ore is higher than that of the low-aluminum laterite nickel ore, and the TFe content is lower than that of the low-aluminum laterite nickel ore. Moreover, the difference in TFe content between the medium nickel ore and the low-aluminum laterite nickel ore is greater than the difference in Ni content. The total addition ratio of the low-aluminum laterite nickel ore and the medium nickel ore is limited to a Ni content of 0.8-0.85% in the sintered ore obtained after sintering. The iron oxide scale is a byproduct produced in the production of steelmaking and rolling. The iron oxide scale is used as a TFe supplement. The amount of the iron oxide scale added is limited to the TFe content of the sintered ore obtained after sintering being 48-50%. The raw materials of the sintering process also include quicklime (CaO), and the CaO is used as an alkalinity regulator. The amount of CaO added is limited to the basicity CaO / SiO2 in the sintered ore being controlled within the range of 0.9 to 1.5; The raw materials of the sintering process also include serpentine, which is used as a supplement for MgO and SiO2, and the amount of serpentine added is limited to SiO2>6.0% and MgO>3.0% in the sintered ore; The sintered ore for low-nickel iron water production is obtained through the sintering process.
[0015] The inventor provides two embodiments (embodiment 1 and embodiment 2) and two comparative examples (comparative example 1 and comparative example 2). The ore blending compositions of the sintering process corresponding to the embodiment 1, embodiment 2, comparative example 1 and comparative example 2 are shown in Table 1 below.
[0016] Table 1
[0017] The compositions of the conventional low-aluminum laterite nickel ore, medium nickel ore 01, conventional low-aluminum laterite ore, conventional high-aluminum laterite nickel ore and medium nickel ore 02 used in the above embodiments and comparative examples are shown in Table 2 below: Table 2 (Unit: %)
[0018] It can be seen from Table 2 that the iron grade (i.e. TFe content) of the medium nickel mine 01 is relatively low, only 31.52%, which is a certain gap from the 49.31% grade of the conventional low-aluminum laterite nickel ore; the nickel content of the medium nickel mine 01 is 1.25%, which is 0.39% higher than the 0.86% of the conventional low-aluminum laterite nickel ore; the iron grade of the medium nickel mine 02 is relatively high, reaching 43.97%, but the nickel content is 1.16%, which is less than the 1.25% nickel content of the medium nickel mine 01. In addition, the SiO2 and MgO contents of the medium nickel mine 01 are relatively high, reaching 21.78% and 11.68% respectively, and the SiO2 and MgO of the medium nickel mine 02 are also slightly higher than the conventional low-aluminum laterite nickel ore, reaching 9.48% and 4.49%.
[0019] The sintering indexes corresponding to the above embodiments and comparative examples are shown in Table 3 below: Table 3
[0020] It can be seen from the data in Table 3 that the sintered ore obtained by the low-nickel iron water production process with the addition of medium nickel ore in Example 1 and Example 2 can meet the composition requirements of 201 stainless steel for the production of low-nickel iron water sintered ore, wherein the requirements of 201 stainless steel for the production of low-nickel iron water sintered ore are: TFe>48%, SiO2>6.0%, MgO>3.0%, Al2O3<7%, basicity: 0.9-1.3. In addition, by comparing Example 1 with Comparative Example 1, and by comparing Example 2 with Comparative Example 2, it can be seen that after adding medium nickel ore, the output of the obtained sintered ore is significantly improved. After using medium nickel ore, due to the high content of SiO2 and MgO in the medium nickel ore, the proportion of snake mosquito stone is no longer used during sintering and batching, and the proportion is reduced from 0.59% to 0%, which can reduce the use of serpentine powder by nearly 120t / d.
[0021] The inventors also used the sintered ore obtained by the sintering process of the above-mentioned embodiments and comparative examples to carry out a blast furnace smelting process. The raw materials of the blast furnace smelting process include iron nuggets and the sintered ore obtained by the sintering process, and the blast furnace molten iron, i.e. the low-nickel molten iron (low-nickel molten iron for 201 stainless steel production) is obtained by blast furnace reduction smelting.
[0022] The blast furnace smelting indicators corresponding to the above embodiments and comparative examples are shown in Table 4 below: Table 4
[0023] It can be seen from Table 4 that after adding medium nickel ore (Example 1 and Example 2), the unit consumption of iron ore for blast furnace increased from 55kg / t iron to 122kg / t iron, and from 100.9kg / t iron to 148.8kg / t iron; at the same time, the nickel content in low-nickel iron water was maintained at 1.40%; after using medium nickel ore (Example 1 and Example 2), the average daily output of low-nickel iron water in the blast furnace can be increased from 4134.8t to 4153.8t, and from 4035.6t to 4297.3t.
[0024] Based on the collected data on sinter composition, coke ratio, coal ratio, daily average molten iron volume, etc., under the condition of the same raw material and fuel prices, the ore blending cost calculation model is used to calculate the molten iron cost. The test results are shown in Table 5 below: Table 5
[0025] From the calculation results, it can be seen that after using medium nickel ore, the blast furnace coke ratio decreases slightly, the output increases, and the corresponding iron cost is lower than that without using laterite nickel ore.
[0026] The applicant produces more than 4,300 tons of molten iron per day. Taking 4,300 tons of molten iron per day as an example, compared with comparative example 1, the daily molten iron cost reduction amount of Example 1 is: 4,300*22=94,600 yuan; compared with comparative example 2, the daily molten iron cost reduction amount of Example 2 is: 4,300*52=223,600 yuan, and the annual molten iron cost reduction amount is: 81,614,000 yuan.
[0027] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent process changes made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.
Claims
1. A process for producing low-nickel molten iron with medium nickel ore, comprising a sintering process; characterized in that: The raw materials of the sintering process include low-aluminum laterite nickel ore, medium nickel ore and iron oxide scale; The medium nickel ore is a type of nickel ore with a Ni content of 1.2-1.6% and a TFe content of 28-45%. The Ni content of the medium nickel ore is higher than that of the low-aluminum laterite nickel ore, and the TFe content is lower than that of the low-aluminum laterite nickel ore. Moreover, the difference in TFe content between the medium nickel ore and the low-aluminum laterite nickel ore is greater than the difference in Ni content. The total addition ratio of the low-aluminum laterite nickel ore and the medium nickel ore is limited to a Ni content of 0.8-0.85% in the sintered ore obtained after sintering. The iron oxide scale is a byproduct produced in the production of steelmaking and rolling. The iron oxide scale is used as a TFe supplement. The amount of the iron oxide scale added is limited to a TFe content of 48-50% in the sintered ore obtained after sintering. The sintered ore for low-nickel iron water production is obtained through the sintering process.
2. The process for producing low-nickel molten iron with medium nickel ore according to claim 1, characterized in that: The raw materials for the sintering process also include CaO, which is used as a basicity regulator. The amount of CaO added is limited to controlling the basicity CaO / SiO2 in the sintered ore to be 0.9 to 1.
5.
3. The process for producing low-nickel molten iron with medium nickel ore according to claim 1, characterized in that: The raw materials for the sintering process also include serpentine, which serves as a supplement for MgO and SiO2. The added amount of the serpentine is limited to SiO2>6.0% and MgO>3.0% in the sintered ore.
4. The process for producing low-nickel molten iron with medium nickel ore according to claim 3, characterized in that: The MgO and / or SiO2 content of the medium nickel ore is higher than that of the low-alumina laterite nickel ore.
5. The process for producing low-nickel molten iron with medium nickel ore according to claim 4, characterized in that: The added amount of the serpentine is 0.
6. The process for producing low-nickel molten iron with medium-nickel ore according to claim 1, characterized in that: The low-aluminum laterite nickel ore is replaced by a composition obtained by adding low-aluminum laterite ore to high-aluminum laterite nickel ore in proportion.
7. The process for producing low-nickel molten iron with medium nickel ore according to claim 1, characterized in that: The blast furnace smelting process is carried out after the sintering process; the raw materials of the blast furnace smelting process include iron block ore and sintered ore obtained by the sintering process, and blast furnace molten iron, i.e. the low-nickel molten iron, is obtained by blast furnace reduction smelting.