Preparation method of laterite-nickel ore cold-pressed block

Abstract

The invention provides a preparation method of a laterite-nickel ore cold-pressed block, and belongs to the technical field of metal smelting. The preparation method provided by the invention comprises the following steps: uniformly mixing 100 parts by mass of laterite-nickel ore, 2-5 parts by mass of an active agent, 4-9 parts by mass of an exciting agent, 0.1-1.5 parts by mass of a reinforcing agent and water to obtain a mixture, and sequentially briquetting and curing the mixture to obtain a laterite-nickel ore cold-pressed block; the mass percentage content of the water in the mixture is 16-19%. The laterite-nickel ore is prepared in a cold pressing block mode, the activating agent, the exciting agent and the reinforcing agent are added into the laterite-nickel ore, the high temperature resistance and strength of the laterite-nickel ore can be improved, and the utilization rate of the laterite-nickel ore is increased. The method is simple in process, safe to operate and easy to implement.

Description

Technical Field

[0001] The invention relates to the technical field of metal smelting, and in particular to a method for preparing a laterite nickel ore cold pressed block. Background Art

[0002] The sintering-blast furnace process for treating laterite nickel ore is the mainstream process for smelting nickel iron from laterite nickel ore due to its advantage of large output. It overcomes many smelting problems such as large slag volume and low furnace iron temperature. Laterite nickel ore is a low-grade complex ore and cannot be pre-enriched using processes such as ore dressing. The quality of nickel iron products mainly depends on the quality of the sintered ore entering the blast furnace. However, laterite nickel ore sintered ore generally has the problems of low compressive strength and poor high temperature resistance. Existing research always screens high-quality laterite nickel ore on a large scale and controls the sintering process to improve the strength and high temperature resistance of the sintered ore, which does not have industrial production value. Therefore, it is of great practical significance to develop the preparation of cold-pressed laterite nickel ore to improve its high temperature resistance and compressive strength.

[0003] Patent 202211261380.5 discloses a method for strengthening the sintering of limonite-type laterite nickel ore, controlling the aluminum content of the sintering mixture, reducing the liquid phase generation temperature, and improving the strength of the laterite nickel ore sinter. This patent does not consider the high temperature strength of the sintered ore, which will reduce its application effect in blast furnace smelting. Patent 201810025624.7 discloses a method for strengthening the sintering of laterite nickel ore by multi-factor coupling, controlling the composition requirements of laterite nickel ore and the parameter requirements during the sintering process, and improving the strength of the sintered ore. This patent has too high requirements for the composition of laterite nickel ore, and the sintering process is too complicated to operate, making industrial-scale production difficult. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a method for preparing a laterite nickel ore cold pressed block. The preparation method provided by the present invention is simple, safe to operate, and easy to implement. The obtained laterite nickel ore cold pressed block has high high temperature resistance and compressive strength.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention is a method for preparing a laterite nickel ore cold pressed block, comprising: uniformly mixing 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 by weight to obtain a mixture, and then briquetting and curing the mixture in sequence to obtain a laterite nickel ore cold pressed block;

[0007] The mass percentage of water in the mixture is 16-19%.

[0008] A second technical solution of the present invention is a laterite nickel ore cold-pressed block prepared by the above-mentioned 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 briquette, which uses the above-mentioned preparation method to prepare laterite nickel ore cold briquette.

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

[0011] The invention prepares the laterite nickel ore in the form of cold pressed blocks, and adds an activator, an activator and a reinforcing agent to the laterite nickel ore, so as to improve the high temperature resistance and strength of the laterite nickel ore. The invention improves the utilization rate of the laterite nickel ore, and the invention has a simple process, safe operation and is easy to implement. DETAILED DESCRIPTION

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

[0013] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0014] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0015] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

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

[0017] The invention mixes laterite nickel ore with an active agent, an activator and a reinforcing agent in a specific ratio, controls the water content of the mixture, and the conditions for briquetting and curing, thereby obtaining a laterite nickel ore cold pressed block with good high temperature resistance and compression resistance. The invention can improve the high temperature resistance and compression resistance of the laterite nickel ore cold pressed block by limiting the specific ratio of the raw materials, the specific water content, the briquetting and curing conditions.

[0018] Specifically, the present invention provides a method for preparing a laterite nickel ore cold pressed block, comprising: uniformly mixing 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 by weight to obtain a mixture, and then briquetting and curing the mixture in sequence to obtain a laterite nickel ore cold pressed block;

[0019] The mass percentage of water in the mixture is 16-19%.

[0020] In the present invention, excessive additives (activator, stimulator and reinforcing agent) will cause the laterite nickel ore particles to become coarser, the gaps to decrease, and the molecular structure to deviate from the ideal state, thereby causing the melting temperature of the laterite nickel ore cold pressed block to decrease; while too little additives will reduce the activity benefit, also causing the melting temperature to decrease.

[0021] In the present invention, if the water content in the mixture is too much, the adhesion and bonding force between the particles will be weakened, and the mechanical strength will be reduced. If the water content is too low, it will make it difficult to bond, the particles will be loose, and the density of the laterite nickel ore cold-pressed block will be low and the compressive strength will be reduced.

[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 contents of iron and silicon in laterite nickel ore in the present invention are preferably the above parameters is that too much iron content in laterite nickel ore will affect the performance of the additive and reduce the high temperature strength of the obtained laterite nickel ore cold pressed block; too little iron content will affect its subsequent use in the blast furnace. Too much silicon content will weaken the compressive performance of the cold pressed block, and too little silicon content will reduce the cost-effectiveness of the additive.

[0024] In some embodiments of the present invention, the active agent 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] The invention adds additives such as an activator, an activator and a reinforcing agent to the laterite nickel ore. The presence of these additives can make the cold pressed block generate a silicon-aluminum network three-dimensional structure, thereby enhancing the high temperature resistance and compressive strength of the laterite nickel ore pressed block, thereby improving the utilization rate of the laterite nickel ore.

[0028] In some embodiments of the present invention, the conditions of the briquetting are set as follows: static pressure is divided into three stages, the first stage static pressure is continuously pressurized at 24-28Mpa for 2-7s, then the pressure is released to 18-19MPa and continued for 40-60s, and then the pressure is released; the second stage static pressure is continuously pressurized at 29-31Mpa for 3-5s, then the pressure is released to 18-19MPa and continued for 70-80s, and then the pressure is released; the third stage static pressure is continuously pressurized at 34-37Mpa for 4-7s, and then the pressure is released. The three-stage static pressure method in the present invention can reduce the microscopic roughness of the surface of the briquetting and improve the compressive strength of the briquetting.

[0029] In some embodiments of the present invention, the size of the cold-pressed laterite nickel ore blocks is set to be rectangular bricks 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 the present invention, if the curing temperature is too high and the humidity is too low, the moisture on the surface of the briquette will be lost quickly, resulting in cracks and reducing the compressive strength; if the curing temperature is too low and the humidity is too high, the briquette will swell and reduce the compressive strength. Therefore, the preferred curing conditions of the present invention are within the above parameter range.

[0032] It can be seen from the above content that the present invention limits the composition of the laterite nickel ore, as well as the types and addition amounts of the added activators, stimulants and reinforcing agents, and further limits the water content of the mixture, and limits the time, temperature and humidity during the briquetting process and the curing process, and designs a method for preparing cold briquetting of laterite nickel ore with simple process, safe operation and easy implementation, which can improve the high temperature resistance and compressive strength of the laterite nickel ore, and has important significance in practical application.

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

[0034] The present invention also provides a method for improving the high temperature resistance and compressive strength of laterite nickel ore briquette, and the laterite nickel ore cold briquette is prepared by using the above preparation method.

[0035] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

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

[0037] Example 1

[0038] Step 1. 100 parts of laterite nickel ore, 2.4 parts of silica fume, 4.84 parts of activator, 0.3 parts of basalt fiber and water are uniformly mixed to obtain a mixture; the total iron content of the laterite nickel ore is 51.54wt%, and the silicon content is 3.14wt%; 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 17.5wt%.

[0039] Step 2. The mixture is pressed and cured in sequence to obtain laterite nickel ore cold pressed blocks; the pressing conditions are: static pressing in three stages, the first stage is static pressing at 25.4 MPa for 3 seconds, then the pressure is released to 18.2 MPa and continued for 45 seconds, and then the pressure is released; the second stage is static pressing at 29.6 MPa for 3 seconds, then the pressure is released to 18.6 MPa and continued for 73 seconds, and then the pressure is released; the third stage is static pressing at 34.6 MPa for 5 seconds, and then the pressure is released; the curing conditions are: curing time for 48 hours under the conditions of temperature 17.6 ° C and humidity 78.4%. The shape of the cold pressed block is a rectangular brick of 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° C. and a compressive strength of 1224N.

[0041] Example 2

[0042] Step 1. 100 parts of laterite nickel ore, 3.5 parts of silica fume, 5.63 parts of activator, 0.5 parts of basalt fiber and water are uniformly mixed to obtain a mixture; the total iron content of the laterite nickel ore is 49..46wt%, and the silicon content is 2.67wt%; 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 18.3wt%.

[0043] Step 2. The mixture is pressed and cured in sequence to obtain laterite nickel ore cold pressed blocks; the pressing conditions are: static pressing in three stages, the first stage is static pressing at 26.6 MPa for 3 seconds, then the pressure is released to 18.5 MPa for 55 seconds, and then the pressure is released; the second stage is static pressing at 30.5 MPa for 3 seconds, then the pressure is released to 18.6 MPa for 73 seconds, and then the pressure is released; the third stage is static pressing at 34.6 MPa for 6 seconds, and then the pressure is released; the curing conditions are: curing time of 56 hours under the conditions of temperature 18.4 ° C and humidity 81.2%. The shape of the cold pressed block is a rectangular brick of 22.3×14.1×6.7 mm.

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

[0045] Example 3

[0046] Step 1. 100 parts of laterite nickel ore, 4.3 parts of silica fume, 6.67 parts of activator, 0.7 parts of basalt fiber and water are uniformly mixed to obtain a mixture; the total iron content of the laterite nickel ore is 53.24wt%, and the silicon content is 2.25wt%; 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 17.5wt%.

[0047] Step 2. The mixture is pressed and cured in sequence to obtain laterite nickel ore cold pressed blocks; the pressing conditions are: static pressing in three stages, the first stage is static pressing at 27.5 MPa for 4 seconds, then the pressure is released to 18.7 MPa and continued for 45 seconds, and then the pressure is released; the second stage is static pressing at 30.5 MPa for 3 seconds, then the pressure is released to 18.6 MPa and continued for 73 seconds, and then the pressure is released; the third stage is static pressing at 36.7 MPa for 7 seconds, and then the pressure is released; the curing conditions are: curing time of 72 hours under the conditions of temperature 20.5 ° C and humidity 84.4%. The shape of the cold pressed block is a rectangular brick of 21.6×13.5×6.8 mm.

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

[0049] Comparative Example 1

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

[0051] The laterite nickel ore sintered block prepared in this comparative example has a melting temperature of 1234° C. and a compressive strength of 1008N.

[0052] Comparative Example 2:

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

[0054] Step 2. The mixture is briquetting and curing in sequence to obtain laterite nickel ore cold briquette, and the briquetting conditions are: one cold pressing, the pressure is 17MPA, and the time is 45s; the curing temperature is 25°C, the humidity is 86%, and the curing time is 36h.

[0055] The laterite nickel ore cold pressed block prepared in this comparative example has a melting temperature of 1331° C. and a compressive strength of 1043N.

[0056] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing cold-pressed laterite nickel ore briquettes, characterized in that: 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 by weight to obtain a mixture, and then the mixture is briquetting and curing in sequence to obtain a laterite nickel ore cold briquette; The mass percentage of water in the mixture is 16-19%.

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

3. The method for preparing cold-pressed laterite nickel ore according to claim 1, characterized in that: The active agent is silica fume.

4. The method for preparing cold-pressed laterite nickel ore according to claim 1, characterized in that: The activator is a mixture of water glass and sodium hydroxide, and the modulus of the activator is 0.75-1.

5.

5. The method for preparing cold-pressed laterite nickel ore according to claim 1, characterized in that: The reinforcing agent is basalt fiber.

6. The method for preparing cold-pressed laterite nickel ore according to claim 1, characterized in that: The conditions of the pressing block are set as follows: static pressure is divided into three stages, in the first stage, the static pressure is continuously pressurized at 24-28Mpa for 2-7s, then the pressure is reduced to 18-19MPa and continued for 40-60s, and then the pressure is released; in the second stage, the static pressure is continuously pressurized at 29-31Mpa for 3-5s, then the pressure is reduced to 18-19MPa and continued for 70-80s, and then the pressure is released; in the third stage, the static pressure is continuously pressurized at 34-37Mpa for 4-7s, and then the pressure is released.

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

8. A laterite nickel ore cold pressed block prepared by the preparation method according to any one of claims 1 to 7.

9. A method for improving the high temperature resistance and compressive strength of laterite nickel ore briquette, characterized in that: The laterite nickel ore cold pressed blocks are prepared by the preparation method described in any one of claims 1 to 7.