Preparation method of laterite nickel ore cold briquetting

Abstract

The application provides a preparation method of laterite nickel ore cold briquetting, and belongs to the technical field of metal smelting. The preparation method provided by the application is as follows: 100 parts of laterite nickel ore, 2-5 parts of an active agent, 4-9 parts of an activator, 0.1-1.5 parts of a reinforcing agent and water are uniformly mixed to obtain a mixture, and then the mixture is sequentially subjected to briquetting and curing to obtain laterite nickel ore cold briquetting; the mass percentage of water in the mixture is 16-19%. The laterite nickel ore is prepared in the form of cold briquetting, and the laterite nickel ore is added with an active agent, an activator and a reinforcing agent, so that the high-temperature resistance and strength of the laterite nickel ore can be improved, and the utilization rate of the laterite nickel ore is improved. The application has the advantages of simple process, safe operation and easy implementation.

Description

Technical Field

[0001] This invention relates to the field of metal smelting technology, and in particular to a method for preparing cold-pressed laterite nickel ore briquettes. Background Technology

[0002] The sintering-blast furnace process for laterite nickel ore is currently the mainstream technology for smelting nickel-iron from laterite nickel ore due to its high yield, overcoming many smelting challenges such as large slag volume and low molten iron temperature in the hearth. Laterite nickel ore is a low-grade, complex ore that cannot be pre-enriched using beneficiation processes; the quality of the nickel-iron product mainly depends on the quality of the sinter entering the blast furnace. However, laterite nickel ore sinter generally suffers from low compressive strength and poor high-temperature resistance. Existing research focuses on large-scale screening of high-quality laterite nickel ore and controlling the sintering process to improve the strength and high-temperature resistance of the sinter, but this lacks industrial production value. Therefore, developing a cold-pressed briquette preparation method for laterite nickel ore to improve its high-temperature resistance and compressive strength is of significant practical importance.

[0003] Patent 202211261380.5 discloses a method for strengthening the sintering of limonite-type lateritic nickel ore, which controls the aluminum content of the sintering mixture, lowers the liquid phase formation temperature, and increases the strength of the sintered lateritic nickel ore. However, this patent does not consider the high-temperature resistance of the sintered ore, which may reduce its application effect in blast furnace smelting. Patent 201810025624.7 discloses a method for strengthening the sintering of lateritic nickel ore through multi-factor coupling and synergistic methods, which controls the compositional requirements of the lateritic nickel ore and the parameter requirements during the sintering process to increase the strength of the sintered ore. However, this patent places excessively high requirements on the composition of the lateritic nickel ore, and the sintering process is overly cumbersome, making large-scale industrial production difficult. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method for preparing lateritic nickel ore cold-pressed blocks. The preparation method provided by this invention is simple, safe to operate, and easy to implement, and the resulting lateritic nickel ore cold-pressed blocks have high high-temperature resistance and high compressive strength.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] One of the technical solutions of the present invention is a method for preparing laterite nickel ore cold-pressed blocks. By mass, 100 parts of laterite nickel ore, 2-5 parts of activator, 4-9 parts of activator, 0.1-1.5 parts of reinforcing agent and water are mixed evenly to obtain a mixture. Then, the mixture is pressed and cured in sequence to obtain laterite nickel ore cold-pressed blocks.

[0007] The water content in the mixture is 16-19% by mass.

[0008] The second technical solution of the present invention is a cold-pressed block of laterite nickel ore prepared by the above preparation method.

[0009] The third technical solution of the present invention is a method for improving the high temperature resistance and compressive strength of laterite nickel ore briquettes, wherein the above-mentioned preparation method is used to prepare laterite nickel ore cold briquettes.

[0010] The present invention discloses the following technical effects:

[0011] This invention prepares laterite nickel ore in the form of cold-pressed briquettes and adds activators, activators, and reinforcing agents to improve the high-temperature resistance and strength of the laterite nickel ore. This invention improves the utilization rate of laterite nickel ore, and the process is simple, safe to operate, and easy to implement. Detailed Implementation

[0012] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0013] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0014] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0015] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0016] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0017] This invention involves mixing lateritic nickel ore with activators, initiators, and reinforcing agents in specific proportions, and controlling the moisture content of the mixture, as well as the briquetting and curing conditions, to obtain a cold-pressed lateritic nickel ore briquette with good high-temperature resistance and compressive strength. By limiting the specific proportions of raw materials and the specific moisture content, briquetting, and curing conditions, this invention can improve the high-temperature resistance and compressive strength of lateritic nickel ore cold-pressed briquettes.

[0018] Specifically, the present invention provides a method for preparing laterite nickel ore cold-pressed blocks. By mass, 100 parts of laterite nickel ore, 2-5 parts of activator, 4-9 parts of activator, 0.1-1.5 parts of reinforcing agent and water are mixed evenly to obtain a mixture. The mixture is then pressed and cured in sequence to obtain laterite nickel ore cold-pressed blocks.

[0019] The water content in the mixture is 16-19% by mass.

[0020] In this invention, excessive additives (activators, activators, and reinforcing agents) will cause laterite nickel ore particles to coarsen, porosity to decrease, and molecular structure to deviate from the ideal state, thereby causing the melting temperature of laterite nickel ore cold-pressed blocks to drop; while insufficient additives will reduce the activation effect, which will also cause the melting temperature to drop.

[0021] In this invention, if the water content in the mixture is too high, it will weaken the adhesion and bonding force between particles and reduce mechanical strength. If the water content is too low, it will make it difficult to bond, resulting in loose particles and low density and reduced compressive strength of the laterite nickel ore cold-pressed blocks.

[0022] In some embodiments of the present invention, the laterite nickel ore has a total iron content of 45-53 wt% and a silicon content of 2.2-3.6 wt%.

[0023] The reason why the iron and silicon content in the laterite nickel ore is preferably as described above in this invention is that excessive iron content in the laterite nickel ore will affect the performance of the additives and reduce the high-temperature strength of the resulting cold-pressed laterite nickel ore briquettes; insufficient iron content will affect its subsequent use in the blast furnace. Excessive silicon content will weaken the compressive strength of the cold-pressed briquettes, while insufficient silicon content will reduce the cost-effectiveness of the additives.

[0024] In some embodiments of the present invention, the activator is silica fume.

[0025] In some embodiments of the present invention, the activator is a mixture of water glass and sodium hydroxide, and the modulus of the activator is 0.75-1.5. The modulus of the activator is the molar ratio of SiO2 to Na2O in the activator.

[0026] In some embodiments of the present invention, the reinforcing agent is basalt fiber.

[0027] This invention adds activators, activators, and reinforcing agents to laterite nickel ore. The presence of these additives causes the cold-pressed ore to form a three-dimensional silicon-aluminum network structure, thereby enhancing the high-temperature resistance and compressive strength of the laterite nickel ore briquettes and improving the utilization rate of laterite nickel ore.

[0028] In some embodiments of the present invention, the conditions for pressing the block are set as follows: static pressure is applied in three stages. In the first stage, static pressure is applied at 24-28 MPa for 2-7 seconds, then depressurized to 18-19 MPa and maintained for 40-60 seconds, after which the pressure is released. In the second stage, static pressure is applied at 29-31 MPa for 3-5 seconds, then depressurized to 18-19 MPa and maintained for 70-80 seconds, after which the pressure is released. In the third stage, static pressure is applied at 34-37 MPa for 4-7 seconds, after which the pressure is released. Using the three-stage static pressure method of the present invention can reduce the micro-unevenness of the block surface and improve the compressive strength of the block.

[0029] In some embodiments of the present invention, the size of the laterite nickel ore cold-pressed block is set as a rectangular brick of (20-24)×(12-16)×(6-8)mm.

[0030] In some embodiments of the present invention, the curing temperature is 17-21°C, the humidity is 75-85%, and the curing time is 48-72 hours.

[0031] In this invention, excessively high curing temperature and low humidity can cause rapid moisture loss from the surface of the pressed block, resulting in cracks and reduced compressive strength; conversely, excessively low curing temperature and high humidity can cause the pressed block to swell due to moisture, also reducing its compressive strength. Therefore, the preferred curing conditions in this invention are within the aforementioned parameter range.

[0032] As can be seen from the above, this invention limits the composition of laterite nickel ore, as well as the types and amounts of added activators, activators, and reinforcing agents, thereby limiting the moisture content of the mixture. By limiting the time, temperature, and humidity during the briquetting and curing processes, a simple, safe, and easy-to-implement method for preparing cold-briquetting laterite nickel ore is designed. This method can improve the high-temperature resistance and compressive strength of laterite nickel ore, which is of great significance in practical applications.

[0033] The present invention also provides a cold-pressed block of laterite nickel ore prepared by the above preparation method.

[0034] The present invention also provides a method for improving the high temperature resistance and compressive strength of laterite nickel ore briquettes, wherein the above-described preparation method is used to prepare laterite nickel ore cold briquettes.

[0035] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0036] All raw materials and reagents used in the examples can be obtained through commercial channels.

[0037] Example 1

[0038] Step 1. Mix 100 parts laterite nickel ore, 2.4 parts silica fume, 4.84 parts activator, 0.3 parts basalt fiber, and water evenly to obtain a mixture; the total iron content in the laterite nickel ore is 51.54 wt%, and the silicon content is 3.14 wt%; the activator is a mixture of water glass and sodium hydroxide, and the modulus of the activator is 0.8; the water content in the mixture is 17.5 wt%.

[0039] Step 2. The mixture is sequentially pressed and cured to obtain laterite nickel ore cold-pressed blocks. The pressing conditions are as follows: static pressing in three stages. In the first stage, static pressing is carried out at 25.4 MPa for 3 seconds, then the pressure is released to 18.2 MPa and held for 45 seconds, after which the pressure is released. In the second stage, static pressing is carried out at 29.6 MPa for 3 seconds, then the pressure is released to 18.6 MPa and held for 73 seconds, after which the pressure is released. In the third stage, static pressing is carried out at 34.6 MPa for 5 seconds, after which the pressure is released. The curing conditions are: curing at 17.6℃ and 78.4% humidity for 48 hours. The cold-pressed blocks are rectangular bricks measuring 21.5 × 12.6 × 6.4 mm.

[0040] The laterite nickel ore cold-pressed block prepared in this embodiment has a melting temperature of 1385℃ and a compressive strength of 1224N.

[0041] Example 2

[0042] Step 1. Mix 100 parts laterite nickel ore, 3.5 parts silica fume, 5.63 parts activator, 0.5 parts basalt fiber, and water evenly to obtain a mixture; the total iron content in the laterite nickel ore is 49.46 wt%, and the silicon content is 2.67 wt%; the activator is a mixture of water glass and sodium hydroxide, and the modulus of the activator is 1; the water content in the mixture is 18.3 wt%.

[0043] Step 2. The mixture is sequentially pressed and cured to obtain laterite nickel ore cold-pressed blocks. The pressing conditions are as follows: static pressing in three stages. In the first stage, static pressing is carried out at 26.6 MPa for 3 seconds, then the pressure is released to 18.5 MPa and held for 55 seconds, after which the pressure is released. In the second stage, static pressing is carried out at 30.5 MPa for 3 seconds, then the pressure is released to 18.6 MPa and held for 73 seconds, after which the pressure is released. In the third stage, static pressing is carried out at 34.6 MPa for 6 seconds, after which the pressure is released. The curing conditions are: curing time of 56 hours at a temperature of 18.4℃ and a humidity of 81.2%. The shape of the cold-pressed blocks is selected as rectangular bricks of 22.3×14.1×6.7mm.

[0044] The laterite nickel ore cold-pressed block prepared in this embodiment has a melting temperature of 1403℃ and a compressive strength of 1296N.

[0045] Example 3

[0046] Step 1. Mix 100 parts laterite nickel ore, 4.3 parts silica fume, 6.67 parts activator, 0.7 parts basalt fiber, and water evenly to obtain a mixture; the total iron content in the laterite nickel ore is 53.24 wt%, and the silicon content is 2.25 wt%; the activator is a mixture of water glass and sodium hydroxide, and the modulus of the activator is 1.25; the water content in the mixture is 17.5 wt%.

[0047] Step 2. The mixture is sequentially pressed and cured to obtain laterite nickel ore cold-pressed blocks. The pressing conditions are as follows: static pressing in three stages. In the first stage, static pressing is carried out at 27.5 MPa for 4 seconds, then the pressure is released to 18.7 MPa and held for 45 seconds, after which the pressure is released. In the second stage, static pressing is carried out at 30.5 MPa for 3 seconds, then the pressure is released to 18.6 MPa and held for 73 seconds, after which the pressure is released. In the third stage, static pressing is carried out at 36.7 MPa for 7 seconds, after which the pressure is released. The curing conditions are: curing time of 72 hours at a temperature of 20.5℃ and a humidity of 84.4%. The shape of the cold-pressed blocks is selected as rectangular bricks of 21.6×13.5×6.8mm.

[0048] The laterite nickel ore cold-pressed block prepared in this embodiment has a melting temperature of 1421℃ and a compressive strength of 1317N.

[0049] Comparative Example 1

[0050] The mixture consists of 100 parts of laterite nickel ore with an iron grade of 47%, 7.2 parts of anthracite (coal particles 1-5mm), 18.5 parts of water, a return ore ratio of 17%, and a sintering basicity of 1.6.

[0051] The laterite nickel ore sintered blocks prepared in this comparative example have a melting temperature of 1234℃ and a compressive strength of 1008N.

[0052] Comparative Example 2:

[0053] Step 1. Mix 100 parts laterite nickel ore, 2.4 parts silica fume, 4.84 parts activator, 0.3 parts basalt fiber, and water evenly to obtain a mixture; the total iron content in the laterite nickel ore is 54 wt%, and the silicon content is 2.1 wt%; the activator is a mixture of water glass and sodium hydroxide, and the modulus of the activator is 0.6; the water content in the mixture is 14 wt%.

[0054] Step 2. The mixture is pressed and cured sequentially to obtain laterite nickel ore cold-pressed briquettes. The pressing conditions are: one cold pressing, pressure of 17 MPa, time of 45 s; curing temperature of 25℃, humidity of 86%, curing time of 36 h.

[0055] The laterite nickel ore cold-pressed blocks prepared in this comparative example have a melting temperature of 1331℃ and a compressive strength of 1043N.

[0056] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing cold-pressed laterite nickel ore briquettes, characterized in that, By weight, 100 parts of laterite nickel ore, 2-5 parts of activator, 4-9 parts of activator, 0.1-1.5 parts of reinforcing agent and water are mixed evenly to obtain a mixture. The mixture is then pressed and cured in sequence to obtain laterite nickel ore cold briquettes. The water content in the mixture is 16-19% by mass. The activator is silica fume; The activator is a mixture of water glass and sodium hydroxide, and the modulus of the activator is 0.75-1.5; The reinforcing agent is basalt fiber.

2. The method for preparing laterite nickel ore cold-pressed briquettes according to claim 1, characterized in that, The laterite nickel ore contains 45-53 wt% total iron and 2.2-3.6 wt% silicon.

3. The method for preparing laterite nickel ore cold-pressed briquettes according to claim 1, characterized in that, The conditions for the pressure block are set as follows: static pressure is applied in three stages. In the first stage, the static pressure is applied continuously at 24-28 MPa for 2-7 seconds, then the pressure is released to 18-19 MPa and maintained for 40-60 seconds, after which the pressure is released. In the second stage, the static pressure is applied continuously at 29-31 MPa for 3-5 seconds, then the pressure is released to 18-19 MPa and maintained for 70-80 seconds, after which the pressure is released. In the third stage, the static pressure is applied continuously at 34-37 MPa for 4-7 seconds, after which the pressure is released.

4. The method for preparing laterite nickel ore cold-pressed briquettes according to claim 1, characterized in that, The curing temperature is 17-21℃, the humidity is 75-85%, and the curing time is 48-72 hours.

5. A cold-pressed block of laterite nickel ore prepared by the preparation method according to any one of claims 1-4.

6. A method for improving the high-temperature resistance and compressive strength of laterite nickel ore briquettes, characterized in that, Lateritic nickel ore cold-pressed blocks are prepared using the preparation method according to any one of claims 1-4.