Method for improving activity of iron tailings powder and application thereof
By using a multidimensional coupled activation method involving mechanical, chemical, and microwave processes, the activity of iron tailings is enhanced, enabling them to replace cement in building materials. This solves the problem of low utilization rate of iron tailings and achieves resource utilization and environmental protection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANLONG (LIAONING) ENERGY SAVING & ENVIRONMENTAL PROTECTION TECH CO LTD
- Filing Date
- 2023-12-26
- Publication Date
- 2026-06-26
Smart Images
Figure BDA0004630303820000071
Abstract
Description
Technical Field
[0001] This invention relates to the field of iron tailings activation treatment technology, and in particular to a method for enhancing the activity of iron tailings powder and its application. Background Technology
[0002] Iron tailings are the waste residue produced after iron ore has undergone processing steps such as crushing, screening, grinding, gravity separation, flotation, and magnetic separation. With the continuous development of my country's steel industry, my country has become one of the countries with the largest increase and reserves of iron tailings resources in the world. For a long time, my country's iron tailings have mainly been disposed of through landfilling. This practice not only consumes a great deal of human, financial, and material resources, but also has a significant negative impact on the ecological environment. Therefore, how to solve the problem of low utilization rate of iron tailings in my country and achieve its resource utilization is an important issue that needs to be addressed today.
[0003] Using iron tailings as a building material can effectively utilize solid waste while reducing resource and energy consumption. Although iron tailings are inert materials and lack the activity of volcanic ash, they contain a large amount of inactive crystalline minerals and chemical components similar to cementitious materials, such as silicon, aluminum, and calcium oxides. Therefore, activating and enhancing the potential activity of these inactive crystalline minerals and silicon, aluminum, and calcium oxides to use them as auxiliary cementitious materials in building materials can not only save traditional resources but also reduce their adverse impact on the ecological environment. Summary of the Invention
[0004] To address the aforementioned problems associated with using iron tailings as building materials, this invention provides a method for enhancing the activity of iron tailings powder. Utilizing a multi-dimensional coupled activation method combining mechanical, chemical, and microwave approaches, this method further enhances the activity of iron tailings compared to conventional mechanical and chemical activation methods. This allows the activated iron tailings powder to replace a significant portion of cement in building materials such as concrete. Specifically, this is achieved through the following techniques.
[0005] A method for enhancing the activity of iron tailings powder includes the following steps:
[0006] The sieved iron tailings powder, along with lime, steel slag powder I, and gypsum, are dried, mixed, and ground.
[0007] After adding the microwave activator, continue stirring until homogeneous, then microwave heat treatment to complete the activity enhancement of the iron tailings powder;
[0008] The raw materials for the microwave activator include 90-95 wt% steel slag powder II, 1-3 wt% silicon carbide, and 2-7 wt% ferrous oxide.
[0009] The above method utilizes a multidimensional coupling activation approach involving mechanical, chemical, and microwave processes. First, mechanical grinding (e.g., ball milling) alters the particle size of iron tailings, increasing the specific surface area and disrupting the mineral structure. This transforms the irregular morphology of the internal structure into a multiphase crystal form, generating lattice distortion, localized damage, and lattice defects. This increases the internal energy of the iron tailings particles, thereby enhancing their activity. During grinding, lime, steel slag, and gypsum contain large amounts of Ca. 2+ In an alkaline environment, it can actively interact with reactive anions such as silicate and aluminate to generate hydrated calcium silicate, hydrated calcium aluminate, and ettringite, effectively promoting the dissolution and disintegration of iron tailings particles and improving their activity. During microwave heating, the Fe element present in the iron tailings exhibits a good microwave absorption effect. With the promotion of the microwave activator, the absorption effect is significantly enhanced, resulting in high electromagnetic energy conversion efficiency and good projection. Ultimately, the silicon-oxygen tetrahedral structure inside and on the surface of the iron tailings particles is effectively bombarded and destroyed, significantly breaking chemical bonds. This method, by combining mechanical, chemical, and microwave treatments, achieves multidimensional coupled activation of iron tailings, greatly enhancing their activity.
[0010] It should be noted that, based on extensive experimental evidence, when the activation method lacks mechanical treatment, or chemical treatment, or microwave heating treatment, or only two of the three treatment methods are used, or the order of the three treatment methods is changed, although it can still play a certain role in activating iron tailings powder, the activation effect will decrease to varying degrees.
[0011] It should be noted that both Steel Slag Powder I and Steel Slag Powder II are steel slag powders. The designations I and II are only used to distinguish the dosage and timing of their use.
[0012] It should be noted that, in the above methods, the purpose of drying is to remove moisture from the materials; therefore, conventional drying methods are sufficient and have no significant impact on improving the activity of iron tailings powder. For example, drying can be completed by heating at an appropriate temperature in a constant temperature drying oven. The purpose of mixing is to ensure that the materials are evenly mixed; therefore, conventional mixing methods are sufficient and have no significant impact on improving the activity of iron tailings powder. For example, stirring can be used.
[0013] Optionally, in the above method, the iron tailings powder, lime, steel slag powder, gypsum, silicon carbide, and ferrous oxide are all commercially available conventional industrial raw materials. Further optionally, ordinary industrial lime is used, hot-quenched steel slag powder is used, and desulfurized gypsum is used.
[0014] Before activating iron tailings powder using the above method, the SiO2 content must be ≥70%, and the powder must be sieved to remove agglomerates and large particles.
[0015] Furthermore, in the method for enhancing the activity of iron tailings powder, the particle size of the iron tailings powder after sieving does not exceed 0.15 mm.
[0016] Generally, a 100-mesh square-hole sieve can be used for sieving.
[0017] Furthermore, the raw materials for the microwave exciter include 94 wt% steel slag powder II, 2 wt% silicon carbide, and 4 wt% ferrous oxide.
[0018] Furthermore, the grinding time is 10-30 minutes, the mass ratio of grinding media to material in the grinding equipment is (1.5-2.5):1, and the rotation speed is 300-500 rpm.
[0019] Optimally, the grinding time is 20 minutes, the mass ratio of grinding media to material in the grinding equipment is 2:1, and the rotation speed is 500 rpm.
[0020] Furthermore, the microwave heating treatment time is 10-30 minutes.
[0021] Furthermore, the iron tailings powder comprises 50-60 parts by weight, the lime comprises 15-25 parts by weight, the steel slag powder I comprises 10-30 parts by weight, and the gypsum comprises 2-7 parts by weight.
[0022] Furthermore, the iron tailings powder comprises 55 parts by weight, the lime comprises 20 parts by weight, the steel slag powder I comprises 20 parts by weight, and the gypsum comprises 5 parts by weight.
[0023] The present invention also provides the application of the activated iron tailings powder prepared by the above method in building materials.
[0024] Furthermore, in the preparation of building materials such as concrete, the amount of activated iron tailings powder added to the concrete to replace cement is 30-50%.
[0025] Compared with the prior art, the advantages of the present invention are as follows: The present invention provides a new method for enhancing the activity of iron tailings powder. By first mixing iron tailings powder with lime, steel slag powder and gypsum evenly, and simultaneously completing mechanical grinding activation and chemical activation processes, and then performing microwave activation, the activity of iron tailings is significantly enhanced. Detailed Implementation
[0026] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0027] In the following examples and comparative examples, the iron tailings powder was provided by Benxi Longxin Mining Co., Ltd., with an SiO2 content of not less than 70%; the lime was ordinary commercially available industrial lime, provided by Fushun Xin Steel Co., Ltd.; the steel slag was hot-quenched steel slag, provided by Fushun Xin Steel Co., Ltd.; and the gypsum was desulfurized gypsum, provided by Fushun Xin Steel Co., Ltd. Silicon carbide and ferrous oxide were directly purchased chemical raw materials.
[0028] Unless otherwise specified, the following embodiments and comparative examples all employ the following methods to activate iron tailings:
[0029] (1) Pretreatment of iron tailings powder: The iron tailings powder is sieved until the particle size is no more than 0.15 mm. Then, the sieved iron tailings powder, lime, steel slag powder I and gypsum are dried in a constant temperature drying oven.
[0030] Optionally, in step (1), the drying temperature is generally 95-105℃, and the corresponding drying time is 18-24h. For ease of comparison, the following examples and comparative examples all use a drying temperature of 95℃ and a drying time of 2h.
[0031] (2) Mix well: Then put these ingredients into a mixer and mix until they are fully mixed and homogeneous.
[0032] Optionally, in step (2), the stirring speed can be selected as 600-1200 r / min, and the stirring time is 10 min-15 min. For ease of comparison, the following examples and comparative examples all use 800 r / min for 15 min.
[0033] (3) Mechanical-chemical activation: The uniformly mixed material is then put into a ball mill for grinding.
[0034] Optionally, in step (3), the grinding method is 300-500 r / min, and the grinding time is 10-30 min.
[0035] (4) Microwave treatment: After adding microwave activator to the material in step (3), continue to stir evenly and microwave heat treatment to complete the activity enhancement of iron tailings powder.
[0036] Optionally, in step (4), the raw materials of the microwave activator include 90-95 parts of steel slag powder II, 1-3 parts of silicon carbide and 2-7 parts of ferrous oxide by mass.
[0037] Optionally, in step (4), the stirring speed can be selected as 600-1200 r / min, and the stirring time is 10 min-15 min. For ease of comparison, the following examples and comparative examples all use 800 r / min for 15 min.
[0038] Optionally, in step (4), the frequency of microwave heating treatment is generally 2450Hz, the power is 1000-2000W, and the treatment time is 10-30min.
[0039] Example 1
[0040] The steps of the iron tailings powder activity enhancement method provided in this embodiment are as follows:
[0041] S1. Pre-treatment of iron tailings powder: The iron tailings powder is passed through a 100-mesh square hole sieve to obtain ultrafine iron tailings powder with a particle size of no more than 0.15mm. The ultrafine iron tailings powder, lime, steel slag powder I and gypsum are dried in a constant temperature drying oven at 95℃ for 2h.
[0042] S2. Mixing: Select 55 parts of ultrafine iron tailings powder, 20 parts of lime, 20 parts of steel slag, and 5 parts of gypsum, mix them into a dry powder, put them into a mixer and stir at 800 r / min for 15 min until fully mixed.
[0043] S3, Mechanical-chemical activation: The mixture obtained in step S2 is placed in a ball mill and ground at 500 r / min for 20 min;
[0044] S4. Microwave heating treatment: After adding microwave activator to the material in step S3, stir evenly at 800 r / min for 15 min; finally, microwave heat treatment at 2450 Hz and 2000 W for 10 min is completed; the activity enhancement treatment of iron tailings powder is completed.
[0045] The raw materials for the microwave activator, by mass, include 95 parts of steel slag powder II, 3 parts of silicon carbide, and 2 parts of ferrous oxide.
[0046] Example 2
[0047] The method for enhancing the activity of iron tailings powder provided in this embodiment differs from that in Embodiment 1 in that the raw materials of the microwave activator include, by mass, 92 parts of steel slag powder II, 1 part of silicon carbide, and 7 parts of ferrous oxide.
[0048] Example 3
[0049] The method for enhancing the activity of iron tailings powder provided in this embodiment differs from that in Embodiment 1 in that: in step S2, 60 parts of ultrafine iron tailings powder, 15 parts of lime, 30 parts of steel slag, and 2 parts of gypsum are selected, mixed into a dry powder, and stirred in a mixer.
[0050] Example 4
[0051] The method for enhancing the activity of iron tailings powder provided in this embodiment differs from that in embodiment 1 in that: in step S2, 50 parts of ultrafine iron tailings powder, 25 parts of lime, 30 parts of steel slag, and 7 parts of gypsum are selected, mixed into a dry powder, and stirred in a mixer.
[0052] Example 5
[0053] The method for enhancing the activity of iron tailings powder provided in this embodiment differs from that in Embodiment 1 in that the ball milling parameters in step S3 are 300 r / min and the milling time is 30 min.
[0054] Example 6
[0055] The method for enhancing the activity of iron tailings powder provided in this embodiment differs from that in Embodiment 1 in that the microwave processing parameters in step S4 are a frequency of 2450Hz, a power of 1000W, and a microwave heating time of 30min.
[0056] Comparative Example 1:
[0057] The method for enhancing the activity of iron tailings powder provided in this embodiment differs from that in Embodiment 1 in that microwave heating treatment is not performed. The specific steps are as follows:
[0058] S1. Pre-treatment of iron tailings powder: The iron tailings powder is passed through a 100-mesh square hole sieve to obtain ultrafine iron tailings powder with a particle size of no more than 0.15mm. The ultrafine iron tailings powder, lime, steel slag powder I and gypsum are dried in a constant temperature drying oven at 95℃ for 2h.
[0059] S2. Mixing: Select 55 parts of ultrafine iron tailings powder, 20 parts of lime, 20 parts of steel slag, and 5 parts of gypsum, mix them into a dry powder, put them into a mixer and stir at 800 r / min for 15 min until fully mixed.
[0060] S3. Mechanical-chemical activation: The mixture obtained in step S2 is placed in a ball mill and ground at 1000 r / min for 20 min to complete the activation enhancement treatment of iron tailings powder.
[0061] Comparative Example 2
[0062] The method for enhancing the activity of iron tailings powder provided in this embodiment differs from that in Embodiment 1 in that it does not involve mechanical-chemical activation treatment. The specific steps are as follows:
[0063] S1. Pre-treatment of iron tailings powder: The iron tailings powder is passed through a 100-mesh square hole sieve to obtain ultrafine iron tailings powder with a particle size of no more than 0.15mm. The ultrafine iron tailings powder, lime, steel slag powder I and gypsum are dried in a constant temperature drying oven at 95℃ for 2h.
[0064] S2. Mixing: Select 55 parts of ultrafine iron tailings powder, 20 parts of lime, 20 parts of steel slag, and 5 parts of gypsum, mix them into a dry powder, put them into a mixer and stir at 800 r / min for 15 min until fully mixed.
[0065] S3. Microwave heating treatment: After adding microwave activator to the material in step S2, stir evenly at 800 r / min for 15 min; finally, microwave heat treatment at 2450 Hz and 2000 W for 10 min is completed; the activity enhancement treatment of iron tailings powder is completed.
[0066] The raw materials for the microwave activator, by mass, include 95 parts of steel slag powder II, 3 parts of silicon carbide, and 2 parts of ferrous oxide.
[0067] Comparative Example 3
[0068] The method for enhancing the activity of iron tailings powder provided in this embodiment differs from that in Embodiment 1 in that it first performs microwave heating treatment followed by mechanical-chemical activation treatment. The specific steps are as follows:
[0069] S1. Pre-treatment of iron tailings powder: The iron tailings powder is passed through a 100-mesh square hole sieve to obtain ultrafine iron tailings powder with a particle size of no more than 0.15mm. The ultrafine iron tailings powder, lime, steel slag powder I and gypsum are dried in a constant temperature drying oven at 95℃ for 2h.
[0070] S2. Mixing: Select 55 parts of ultrafine iron tailings powder, 20 parts of lime, 20 parts of steel slag, and 5 parts of gypsum, mix them into a dry powder, put them into a mixer and stir at 800 r / min for 15 min until fully mixed.
[0071] S3. Microwave heating treatment: After adding microwave activator to the material in step S3, stir evenly at 800 r / min for 15 min; finally, microwave heat treatment at 2450 Hz and 2000 W for 10 min is completed; the activity enhancement treatment of iron tailings powder is completed.
[0072] The raw materials for the microwave activator, by mass parts, include 95 parts of steel slag powder II, 3 parts of silicon carbide, and 2 parts of ferrous oxide;
[0073] S4. Mechanical-chemical activation: The mixture obtained in step S2 is placed in a ball mill and ground at 1000 r / min for 20 min to complete the activation enhancement treatment of iron tailings powder.
[0074] Application Example: Application of the activated iron tailings prepared in the examples and comparative examples in building materials.
[0075] Referring to the method in the national standard GB / T 51003-2014 "Technical Specification for Application of Mineral Admixtures", the activity index of standard mortar specimens containing active iron tailings was tested at 7 days and 28 days.
[0076] The activated iron tailings prepared in the above examples and comparative examples were used to replace a portion of the cement, and were thoroughly mixed with cement (ordinary Portland cement, PO 42.5, Conch Cement Co.) and water at a water-to-binder ratio of 1:2 to obtain a neat cement paste. Then, the neat cement paste was mixed evenly with standard sand at a binder-to-sand ratio of 1:3 to obtain mortar specimens. Finally, the mortar specimens were demolded after 24 hours and cured (20±2℃, 95% relative humidity) to the specified age. The test results are shown in the table below. The blank control refers to the test where sieved iron tailings powder directly replaced a portion of the cement.
[0077] Table 1 Results of Activity Index Test
[0078]
[0079] As can be seen from the table above, when activated iron tailings powder was used to replace cement at proportions of 30%, 50%, and 70%, the activity index at 7 days and 28 days showed a significant downward trend. Compared with Comparative Examples 1-3 and the blank control, the activated iron tailings powder prepared in Examples 1-8 had higher activity and a smaller decrease, making it suitable for construction engineering applications with different needs. When only mechanical-chemical activation treatment was performed on the iron tailings (Comparative Example 1), or only microwave heating treatment was performed on the iron tailings (Comparative Example 2), or the order of mechanical-chemical activation treatment and microwave heating treatment was reversed (Comparative Example 3), the activity index at 7 days and 28 days was slightly higher than that of the blank control. This indicates that although simply using mechanical-chemical activation treatment or microwave heating, or simply adjusting the order of mechanical-chemical activation and microwave heating, can improve the activity of iron tailings to a certain extent, the degree of improvement is significantly less than that of the methods in Examples 1-8.
[0080] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.
Claims
1. A method for enhancing the activity of iron tailings powder, characterized in that, Includes the following steps: The sieved iron tailings powder, along with lime, steel slag powder I, and gypsum, are dried, mixed, and ground. After adding the microwave activator, continue stirring until homogeneous, then microwave heat treatment to complete the activity enhancement of the iron tailings powder; The raw materials for the microwave activator include 90-95 wt% steel slag powder II, 1-3 wt% silicon carbide, and 2-7 wt% ferrous oxide.
2. The method for enhancing the activity of iron tailings powder according to claim 1, characterized in that, The particle size of the iron tailings powder after sieving does not exceed 0.15 mm.
3. The method for enhancing the activity of iron tailings powder according to claim 1, characterized in that, The microwave exciter consists of 94 wt% steel slag powder II, 2 wt% silicon carbide, and 4 wt% ferrous oxide.
4. The method for enhancing the activity of iron tailings powder according to claim 1, characterized in that, The grinding time is 10-30 minutes, the mass ratio of grinding media to material in the grinding equipment is (1.5-2.5):1, and the rotation speed is 300-500 rpm.
5. The method for enhancing the activity of iron tailings powder according to claim 1, characterized in that, The microwave heating treatment lasts for 10-30 minutes and has a power of 1000W-2000W.
6. The method for enhancing the activity of iron tailings powder according to any one of claims 1-5, characterized in that, The iron tailings powder comprises 50-60 parts by weight, lime comprises 15-25 parts by weight, steel slag powder I comprises 10-30 parts by weight, and gypsum comprises 2-7 parts by weight.
7. The method for enhancing the activity of iron tailings powder according to claim 6, characterized in that, The iron tailings powder comprises 55 parts by weight, lime comprises 20 parts by weight, steel slag powder I comprises 20 parts by weight, and gypsum comprises 5 parts by weight.
8. The application of the activated iron tailings powder prepared by the method of claim 1 in building materials.
9. The application according to claim 8, characterized in that, The amount of activated iron tailings powder used to replace cement in concrete is 30-50%.