Aluminum-titanium based composite bonding slurry, preparation method thereof and application in fluorine-containing iron ore pellets

Abstract

The present invention discloses an aluminum-titanium-based composite bonding slurry, a preparation method thereof, and an application thereof in fluorine-containing iron ore pellets, and belongs to the technical field of solid waste resource utilization. The aluminum-titanium-based composite bonding slurry includes bauxite beneficiation tailings, vanadium-titanium beneficiation tailings, humic acid, and water. When used to replace the conventional binder of fluorine-containing iron ore pellets, the iron grade of fluorine-containing pellets can be improved, and the metallurgical properties of fluorine-containing pellets can be significantly improved. In particular, the bauxite beneficiation tailings and vanadium-titanium beneficiation tailings in the composite bonding slurry are widely available, and resource utilization is achieved while treating solid waste. In addition, the preparation method of the composite bonding slurry is simple to operate, has low production cost, is environmentally friendly, and meets the requirements of industrial production.

Description

Technical Field

[0001] The invention relates to a bonding slurry, in particular to an aluminum-titanium based composite bonding slurry, and also to a preparation method of the aluminum-titanium based composite bonding slurry and application of the same in fluorine-containing iron ore pellets, belonging to the technical field of solid waste resource utilization. Background Art

[0002] Bauxite tailings and vanadium-titanium magnetite tailings are large-scale solid waste resources from the beneficiation of bauxite and vanadium-titanium magnetite. They are often treated in the form of stockpiling because of their huge output, rich in various valuable elements but low comprehensive utilization rate.

[0003] At the same time, fluorine-containing iron ore, as a typical low-silicon, high-fluorine, high-alkali metal mineral, has significant problems in the production of pellets. Due to the presence of fluorine and alkali metal elements, not only the compressive strength of the pellets is reduced, but also the reduction expansion and droplet performance deterioration are aggravated, which significantly limits the application effect of fluorine-containing iron ore pellets in the blast furnace smelting process. This makes the application of this mineral in smelting extremely challenging, and there is an urgent need to solve these problems through technological improvements. In addition, bentonite is widely used in the production of fluorine-containing iron ore pellets as a common binder. However, the high addition of bentonite brings a series of new problems: on the one hand, it significantly increases the production cost; on the other hand, it greatly reduces the iron grade of the pellets, which has a negative impact on blast furnace smelting.

[0004] In order to solve this technical bottleneck, some studies in recent years have begun to try to use other binders, such as serpentine, to replace bentonite to improve the metallurgical properties of fluorine-containing iron ore pellets. However, these alternatives also face limitations in practical applications, such as limited improvement effects, high costs, and complex processes, making it difficult to achieve large-scale promotion. Summary of the invention

[0005] In view of the technical problems such as high dosage of binder and poor metallurgical properties of finished balls in the existing production process of fluorine-containing iron ore pellets, the first purpose of the present invention is to provide an aluminum-titanium based composite bonding slurry, which can replace the conventional fluorine-containing pellet binder, reduce the amount of binder used in the production process of fluorine-containing iron ore pellets, and can significantly improve the strength and metallurgical properties of fluorine-containing iron ore pellets. At the same time, solid waste resources such as bauxite ore dressing tailings and vanadium-titanium ore dressing tailings can be effectively utilized, which can alleviate the environmental pressure caused by solid waste storage, and provide high-performance iron ore pellet raw materials for blast furnace smelting, thereby promoting the sustainable utilization of resources and the advancement of metallurgical technology.

[0006] The second object of the present invention is to provide a method for preparing an aluminum-titanium based composite bonding slurry, which is simple to operate, has low raw material cost, and can meet the needs of industrial production.

[0007] The third object of the present invention is to provide an application of an aluminum-titanium-based composite bonding slurry in the preparation of fluorine-containing iron ore pellets. When used in the production process of fluorine-containing iron ore pellets, it not only has a small addition amount and excellent bonding effect, but also can improve the compressive strength and metallurgical properties of the pellets, while realizing the resource utilization of ore dressing tailings and reducing environmental pollution.

[0008] In order to achieve the above technical objectives, the present invention provides an aluminum-titanium based composite bonding slurry, which includes bauxite ore dressing tailings, vanadium-titanium ore dressing tailings, humic acid and water; the vanadium-titanium ore dressing tailings and the bauxite ore dressing tailings are composed according to a mass percentage of 20~80%:80~20%; the humic acid is 1~3% of the total mass of the vanadium-titanium ore dressing tailings and the bauxite ore dressing tailings; the water is measured at a solid-liquid mass ratio of 1:0.5~1.5.

[0009] The bauxite ore dressing tailings and vanadium-titanium ore dressing tailings in the aluminum-titanium-based composite bonding slurry of the present invention have sticky particles that are closely combined with humic acid, which can enhance the stability, adhesion and dispersion of the slurry, thereby significantly improving the green ball and dry ball strength of the pellets and reducing the amount of binder added. At the same time, the bauxite ore dressing tailings and vanadium-titanium ore dressing tailings can also provide oxides such as Al2O3, TiO2, and SiO2, thereby improving the strength and droplet performance of the fluorine-containing iron ore pellets.

[0010] The main active ingredients of the aluminum-titanium-based composite bonding slurry of the present invention are inorganic components and humic acid organic components composed of vanadium-titanium ore dressing tailings and bauxite ore dressing tailings. The two are controlled within an appropriate ratio range, which can control costs and improve pellet performance while ensuring excellent bonding performance. Based on the synergistic effect of the active ingredients in the two minerals of vanadium-titanium ore dressing tailings and bauxite ore dressing tailings, such as the main components of bauxite ore dressing tailings are Al2O3 and SiO2, and the main components of vanadium-titanium ore dressing tailings are TiO2 and SiO2, the two are used in combination according to an appropriate ratio, and the ratio range of these oxides can be adjusted to improve the bonding effect of the composite binder and the metallurgical properties of the pellets.

[0011] As a more preferred solution, the mass content of Al2O3 in the bauxite beneficiation tailings is 10%~25%, and the mass content of SiO2 is 30%~60%.

[0012] As a more preferred solution, the mass content of TiO2 in the vanadium-titanium ore dressing tailings is 8% to 15%, and the mass content of SiO2 is 35% to 50%.

[0013] The appropriate amount of SiO2 in the bauxite beneficiation tailings and vanadium-titanium ore beneficiation tailings of the present invention can ensure that the pellets produce an appropriate amount of liquid phase during the roasting process to improve the strength of the oxidized pellets, while Al2O3 and TiO2 can ensure that the fluorine-containing iron ore pellets will not soften too quickly during the blast furnace smelting process to reduce the permeability of the blast furnace, thereby obtaining good droplet performance.

[0014] As a preferred solution, the particle size of the bauxite beneficiation tailings and the vanadium-titanium ore beneficiation tailings meets the mass proportion of -10 μm particle size of more than 90%. The bauxite beneficiation tailings and the vanadium-titanium ore beneficiation tailings are ball-milled to an appropriate particle size, and the activation effect of ball milling is utilized to not only increase the specific surface area of ​​the bauxite beneficiation tailings and the vanadium-titanium ore beneficiation tailings, but also give them high activation energy, thereby improving the synergistic effect between them and humic acid, enhancing the bonding performance of the composite binder, and at the same time, the reaction activity of the oxide components in the bauxite beneficiation tailings and the vanadium-titanium ore beneficiation tailings during the roasting process can be improved.

[0015] The present invention also provides a method for preparing aluminum-titanium based composite bonding slurry, which comprises drying and ball-milling the bauxite beneficiation tailings and vanadium-titanium ore beneficiation tailings, uniformly mixing them with humic acid and water, and performing ultrasonic treatment to obtain the slurry.

[0016] In the preparation process of the aluminum-titanium based composite bonding slurry provided by the present invention, the bauxite ore dressing tailings and the vanadium-titanium ore dressing tailings are activated by ball milling, which can improve the adsorption efficiency of humic acid on the surface of the bauxite ore dressing tailings and the vanadium-titanium ore dressing tailings particles, especially under the action of ultrasound, which can improve the dispersion degree of the bauxite ore dressing tailings and the vanadium-titanium ore dressing tailings particles, and also can promote the uniform adsorption of the organic binder in the humic acid on the surface of the tailings particles, thereby achieving a better modification effect.

[0017] As a preferred solution, the drying conditions are: temperature of 200-300° C. and time of 180-250 min.

[0018] As a preferred solution, the conditions for ball milling activation are: a rotation speed of 250-300 rpm, a time of 30-60 min, and a ball-to-material mass ratio of 2:1-5:1. The ball milling activation process can increase the specific surface area of ​​bauxite ore dressing tailings and vanadium-titanium ore dressing tailings, which is beneficial to the subsequent modification process.

[0019] As a preferred solution, the ultrasonic treatment conditions are: temperature of 60-90°C, ultrasonic frequency of 25-30KHz, and ultrasonic time of 30-40 min. Under the preferred ultrasonic conditions, the high dispersibility of the particles of bauxite tailings and vanadium-titanium ore tailings can be promoted, and the reactivity between humic acid and the particles of bauxite tailings and vanadium-titanium ore tailings can be enhanced.

[0020] The present invention also provides an application of an aluminum-titanium based composite bonding slurry for preparing fluorine-containing iron ore pellets.

[0021] As a preferred solution, the aluminum-titanium based composite bonding slurry is sprayed on the fluorine-containing iron ore raw material and water is added to mix evenly to form balls. The obtained raw balls are calcined to obtain finished balls.

[0022] As a preferred solution, the amount of the aluminum-titanium based composite bonding slurry added to the fluorine-containing iron ore raw material is 0.8-1.5% of the dry basis weight of the fluorine-containing iron ore raw material. A small amount of bonding slurry can achieve a good bonding effect, thereby reducing the amount of binder used and significantly improving the iron grade of the pellets.

[0023] As a preferred solution, the roasting conditions are: temperature of 1250~1280℃, time of 20~30min. The selection of roasting temperature plays an important role in the performance of the pellets. If the roasting temperature is too low or the time is too short, the strength of the roasted pellets is low and the metallurgical properties are poor. If the roasting temperature is too high or the time is too long, the strength of the pellets can be improved, but it will lead to increased energy consumption and increased production costs. Therefore, it is necessary to reasonably control the temperature and time during the roasting process to ensure that the compressive strength of the finished pellets reaches more than 2500 N, while the reduction expansion rate does not exceed 20%, and the temperature of the soft melting interval is not less than 50℃.

[0024] Compared with the prior art, the technical solution of the present invention brings the following beneficial technical effects: (1) The main components of the aluminum-titanium based composite bonding slurry of the present invention are bauxite ore dressing tailings and vanadium-titanium ore dressing tailings solid wastes. These two solid wastes are used as inorganic bonding components in the fluorine-containing iron ore pellet binder. They not only play a good bonding role, but also are introduced as high melting point substances to improve the performance of pellets. At the same time, they provide a new way for the utilization of bauxite ore dressing tailings and vanadium-titanium ore dressing tailings, reduce the discharge of waste slag, have good environmental friendliness, and meet the requirements of green production and circular economy.

[0025] (2) The aluminum-titanium-based composite bonding slurry of the present invention uses a combination of bauxite ore dressing tailings, vanadium-titanium ore dressing tailings and humic acid to replace the traditional fluorine-containing iron ore pellet binder (such as bentonite, etc.), which not only reduces the amount of binder added in the pellets to improve the iron grade, but also improves the strength and droplet performance of the fluorine-containing iron ore pellets, which is beneficial to improving the subsequent blast furnace metallurgical performance.

[0026] (3) The preparation method of the aluminum-titanium based composite adhesive slurry of the present invention is simple, low-cost and feasible to operate. DETAILED DESCRIPTION

[0027] The following examples are intended to further illustrate the present invention, rather than to limit the scope of protection of the claims of the present invention.

[0028] In the following examples and comparative examples: the total iron grade of the fluorine-containing iron ore is 64%, the raw material particle size composition is -0.074 mm particle size mass ratio is 92%, and the specific surface area is 820 cm 3 •g -1 .

[0029] In the following examples and comparative examples: the Al2O3 content in the bauxite beneficiation tailings is 21%, and the SiO2 content is 52%. The TiO2 content in the vanadium-titanium ore beneficiation tailings is 14%, and the SiO2 content is 42%. The mass proportion of the particle size of the bauxite beneficiation tailings and the vanadium-titanium ore beneficiation tailings meeting the -10 μm particle size is 95%.

[0030] Example 1 Bauxite tailings and vanadium-titanium tailings were mixed in a mass ratio of 20:80. The mixed materials were dried at 250 °C for 230 minutes. The dried materials were then ball milled with a ball-to-material mass ratio of 3:1, a rotation speed of 280 rpm, and a ball milling time of 35 minutes. The ball-milled materials were mixed with 1.5% humic acid and water with a liquid-solid ratio of 1:0.9, and treated under ultrasonic conditions of 80 °C and 30 kHz for 35 minutes to obtain an aluminum-titanium-based composite bonding slurry. The slurry was sprayed into the fluorine-containing iron ore at an addition ratio of 0.8%, mixed evenly, and then balled. The finished pellets were obtained after calcination at 1260 °C for 20 minutes. The compressive strength of the obtained pellets was 2600 N, and the softening start temperature increased by 54 °C compared with that without the addition of composite binder.

[0031] Example 2 The bauxite tailings and vanadium-titanium tailings were mixed in a mass ratio of 40:60. The mixed material was dried at 230°C for 210 minutes. Then the dried material was milled at a ball-to-material mass ratio of 4:1, a rotation speed of 275 rpm, and a ball milling time of 50 minutes. The ball-milled material was mixed with 1.5% humic acid and water at a liquid-solid ratio of 1:1, and treated at 75°C and 28 kHz ultrasonic conditions for 32 minutes to obtain an aluminum-titanium-based composite bonding slurry. The slurry was sprayed into the fluorine-containing iron ore at an addition ratio of 1.3%, and after mixing evenly, the water content was adjusted to the appropriate pellet water content for pelletizing. The finished pellets were obtained after calcination at 1250°C for 30 minutes. The compressive strength of the obtained pellets was 2550N, and the softening start temperature increased by 52°C compared with that without the addition of composite binder.

[0032] Example 3 The bauxite tailings and vanadium-titanium tailings were mixed in a mass ratio of 50:50. The mixed material was dried at 240°C for 220 minutes. The dried material was then ball milled with a ball-to-material mass ratio of 3:1, a ball milling speed of 260 rpm, and a ball milling time of 35 minutes. The ball-milled material was mixed with 1.5% humic acid and water with a liquid-solid ratio of 1:1, and treated under ultrasonic conditions of 70°C and 25 kHz for 40 minutes to obtain an aluminum-titanium-based composite bonding slurry. The slurry was sprayed into the fluorine-containing iron ore at an addition amount of 1.5%, mixed evenly, and then balled. The finished pellets were obtained after a roasting temperature of 1270°C and a roasting time of 20 minutes. The compressive strength of the obtained pellets was 2650N, and the softening start temperature increased by 60°C compared with that without the addition of the composite binder.

[0033] Example 4 The bauxite tailings and vanadium-titanium tailings were mixed in a mass ratio of 80:20. The mixed materials were dried at a drying temperature of 220°C and a drying time of 210 minutes. The dried materials were then ball milled with a ball-to-material mass ratio of 3:1, a rotation speed of 295 rpm, and a ball milling time of 60 minutes. The ball-milled materials were mixed with 1.5% humic acid and water with a liquid-solid ratio of 1:1, and treated under ultrasonic conditions of 70°C and 28kHz for 30 minutes to obtain an aluminum-titanium-based composite bonding slurry. The slurry was sprayed into the fluorine-containing iron ore at an addition amount of 1.0%, mixed evenly, and then balled. After being roasted at 1250°C for 25 minutes, the finished pellets were obtained. The compressive strength of the obtained pellets was 2500N, and the softening start temperature increased by 50°C relative to that without the addition of the composite binder.

[0034] Comparative Example 1 Compared with Example 1, the only difference is that the finished pellets are obtained after roasting at 1230° C. for 20 minutes. The other process conditions are the same as those in Example 1.

[0035] The results show that the compressive strength of the pellets is 2342N, and the softening start temperature is 8°C higher than that without adding the composite binder. Compared with Example 1, the roasting temperature is reduced by 30°C, the compressive strength of the pellets decreases by 258N, and the softening start temperature decreases by 46°C, indicating that the lower roasting temperature of the slurry is not conducive to improving the strength of the pellets.

[0036] Comparative Example 2 Compared with Example 2, the only difference is that the slurry is sprayed into the fluorine-containing iron ore at a ratio of 0.4%. The other process conditions refer to Example 2.

[0037] The results show that the compressive strength of the pellets is 2435N, and the softening temperature is increased by 25°C compared with that without adding the composite binder. Compared with Example 2, although the process conditions are the same, due to the lower proportion of slurry added, the reduction of the compactness of the pellets and the content of high melting point substances (Al2O3 and TiO2) in the pellets have an adverse effect on the strength and softening temperature of the pellets, and the compressive strength decreases by 115N and the softening temperature decreases by 27°C.

[0038] Comparative Example 3 Compared with Example 3, the only difference is that a single vanadium-titanium ore dressing tailings or a single bauxite ore dressing tailings is used to replace the bauxite ore dressing tailings and vanadium-titanium ore dressing tailings mixed in a mass ratio of 50:50 in Example 3. Other process conditions refer to Example 3.

[0039] The results show that: When single vanadium-titanium ore dressing tailings are used, the compressive strength of the obtained pellets is 2480N, and the softening start temperature increases by 45°C compared with that without adding composite binder.

[0040] When single bauxite tailings are used, the compressive strength of the obtained pellets is 2530N, and the softening start temperature increases by 35℃ compared with that without adding composite binder.

[0041] The use of single vanadium-titanium ore dressing tailings or single bauxite dressing tailings is not conducive to the improvement of pellet strength and initial softening temperature.

[0042] Comparative Example 4 Compared with Example 4, the only difference is that the dried material is ball-milled, the ball-to-material mass ratio is 3:1, the rotation speed is 295 rpm, and the ball-milling time is 20 min. The other process conditions refer to Example 4.

[0043] The compressive strength of the obtained pellets was 2410N, and the softening start temperature increased by 40°C compared with that without adding the composite binder. Compared with Example 4, the slurry ball milling time was shortened by 10min, the compressive strength of the pellets decreased by 90N, and the softening start temperature decreased by 10°C, indicating that the use of a shorter ball milling time is not conducive to the activation of the tailings, resulting in reduced pellet performance.

Claims

1. An aluminum-titanium based composite bonding slurry, characterized in that: Including bauxite beneficiation tailings, vanadium-titanium ore beneficiation tailings, humic acid and water; The vanadium-titanium ore dressing tailings and the bauxite ore dressing tailings are composed of 20-80%:80-20% by mass; The humic acid is 1-3% of the total mass of the vanadium-titanium ore dressing tailings and the bauxite ore dressing tailings; The water is measured at a solid-to-liquid mass ratio of 1:0.5-1.

5.

2. The aluminum-titanium based composite bonding slurry according to claim 1, characterized in that: The Al2O3 mass content in the bauxite beneficiation tailings is 10% to 25%, and the SiO2 mass content is 30% to 60%; The mass content of TiO2 in the vanadium-titanium ore dressing tailings is 8% to 15%, and the mass content of SiO2 is 35% to 50%; The particle size of the bauxite beneficiation tailings and the vanadium-titanium ore beneficiation tailings meets the -10 μm particle size, and the mass proportion of the tailings is more than 90%.

3. The method for preparing an aluminum-titanium based composite adhesive slurry according to claim 1 or 2, characterized in that: The bauxite beneficiation tailings and vanadium-titanium ore beneficiation tailings are dried and ball-milled for activation, then evenly mixed with humic acid and water and subjected to ultrasonic treatment to obtain the product.

4. The method for preparing an aluminum-titanium based composite adhesive slurry according to claim 3, characterized in that: The drying conditions are: temperature of 200-300°C and time of 180-250 min; The conditions for ball milling activation are: a rotation speed of 250-300 rpm, a time of 30-60 min, and a ball-to-material mass ratio of 2:1-5:

1.

5. The method for preparing an aluminum-titanium based composite adhesive slurry according to claim 3, characterized in that: The ultrasonic treatment conditions are: temperature of 60-90° C., ultrasonic frequency of 25-30 KHz, and ultrasonic time of 30-40 min.

6. The use of an aluminum-titanium based composite adhesive slurry according to claim 1 or 2, characterized in that: Used to prepare fluorine-containing iron ore pellets.

7. The use of an aluminum-titanium based composite bonding slurry according to claim 6, characterized in that: The aluminum-titanium based composite bonding slurry is sprayed on the fluorine-containing iron ore raw material and water is added to mix evenly to form balls. The obtained raw balls are calcined to obtain finished balls.

8. The use of an aluminum-titanium based composite bonding slurry according to claim 7, characterized in that: The amount of the aluminum-titanium based composite adhesive slurry added to the fluorine-containing iron ore raw material is 0.8-1.5% of the dry basis mass of the fluorine-containing iron ore raw material.

9. The use of an aluminum-titanium based composite bonding slurry according to claim 7, characterized in that: The calcination conditions are as follows: temperature of 1250-1280° C. and time of 20-30 min.