A method for solidification treatment of iron tailings
By using a mixed pressing method of iron tailings and desulfurization ash, the problems of high solidification cost and uneven strength of iron tailings have been solved, realizing efficient and low-cost resource utilization of tailings, which is suitable for reclamation projects.
Patent Information
- Application Number
- CN202311194704.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-15
- Publication Date
- 2026-01-13
- Estimated Expiration
- 2043-09-15
AI Technical Summary
Existing iron tailings solidification technologies suffer from high costs, uneven strength, and low admixture levels, making it difficult to effectively utilize fine and ultrafine tailings.
Using iron tailings and desulfurization ash as the main raw materials, a high-strength solidified body is prepared by mixing and pressing, controlling the molding pressure and holding time.
It achieves low-cost and high-efficiency iron tailings solidification, improves tailings utilization, reduces environmental pollution risks, and the solidified material can be used in reclamation projects.
Smart Images
Figure CN117285285B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of tailings solidification technology, and in particular to a method for solidifying iron tailings. Background Technology
[0002] With the acceleration of urbanization, the generation and discharge of industrial solid waste are increasing year by year. Iron tailings are solid waste generated after mineral processing. In recent years, my country's annual output of iron tailings has exceeded 500 million tons. In 2020-2021, iron tailings accounted for 51% of the total tailings output, while the comprehensive utilization rate of tailings was only 18.9%. Abandoned iron tailings not only occupy a large amount of land but also pollute the surrounding ecological environment.
[0003] The traditional method for disposing of waste iron tailings is to stockpile them in tailings ponds, which occupies a large amount of land and poses safety hazards and environmental risks. Furthermore, the daily operation of tailings ponds requires substantial capital investment, placing a heavy economic burden on enterprises. Currently, there is considerable research on the solidification treatment of waste iron tailings, with the main method being the mixing and solidification of various raw materials for use as cover soil. However, research on the solidification of fine-grained and ultra-fine-grained tailings is lacking, and this approach suffers from the following problems: firstly, cement is generally used as a raw material, resulting in high costs; secondly, the required types of raw materials are numerous, making it difficult to ensure uniform mixing in practical applications, leading to uneven strength distribution of the solidified body; and thirdly, the maximum tailings content is generally around 60%, which is relatively low. Therefore, developing a low-cost, efficient, and high-strength solidification treatment method for iron tailings is of great significance.
[0004] Application content
[0005] This application provides a method for solidifying iron tailings to solve the technical problem of low solidification efficiency in existing iron tailings.
[0006] This application provides a method for solidifying iron tailings, the method comprising:
[0007] Iron tailings, desulfurization ash and water are mixed evenly to obtain a mixture;
[0008] The mixture is pressed into shape, and the process parameters of the pressing are controlled to obtain a cured body.
[0009] Optionally, by mass fraction, the iron tailings are 50%–90%, the desulfurization ash is 10%–50%, and the concentration of the mixture is 80%–92%.
[0010] Optionally, by mass fraction, the iron tailings are 60%–90%, the desulfurization ash is 10%–40%, and the concentration of the mixture is 80%–90%.
[0011] Optionally, the process parameters for compression molding include molding pressure and holding time; wherein,
[0012] The molding pressure is 10MPa to 40MPa, and the holding time is 20s to 60s.
[0013] Optionally, the molding pressure is 20MPa to 40MPa, and the holding time is 20s to 40s.
[0014] Optionally, the fineness modulus of the iron tailings is ≤0.8.
[0015] Optionally, the iron tailings are magnetite-quartzite type iron tailings.
[0016] Optionally, the desulfurization ash is a byproduct of flue gas desulfurization.
[0017] Optionally, the desulfurization ash meets at least one of the following specifications: particle size D90 of 20μm to 40μm, and specific surface area of 500m². 2 / kg~800m 2 / kg.
[0018] Optionally, the method further includes curing the solidified body.
[0019] The technical solutions provided in this application have the following advantages compared with the prior art:
[0020] This application solidifies iron tailings to produce a stockpile-friendly, environmentally friendly solidified body, enabling rapid and large-scale solidification and resource utilization of iron tailings. It eliminates the need for dedicated tailings dams and uses extremely low-cost desulfurization ash as a solidifying agent, further reducing solidification costs and facilitating large-volume tailings solidification. Furthermore, the solidified body obtained by this application is suitable for safe reclamation at various strengths and avoids the high cost and high carbon dioxide emissions associated with traditional tailings solidification methods using cement.
[0021] In particular, the iron tailings solidification treatment method of this application only requires mixing two raw materials: iron tailings and desulfurization ash. The operation is simple, the mixing process is easier, and the risk caused by uneven strength of the solidified body is reduced. Furthermore, heavy metal ions, and even pollutants such as arsenic and mercury, contained in the iron tailings can be solidified.
[0022] In particular, the iron tailings content in this application can reach up to 90%, which can significantly improve the utilization rate of iron tailings and provide a new approach for the comprehensive utilization of iron tailings. Attached Figure Description
[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 A schematic flowchart of a method for solidifying iron tailings provided in an embodiment of this application;
[0026] Figure 2 This is a schematic diagram of a method for solidifying iron tailings provided in an embodiment of this application. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0028] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.
[0029] In the description of this application, the terms "comprising," "including," etc., mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.
[0030] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.
[0031] In one embodiment of this application, a method for solidifying iron tailings is provided; please refer to [link to relevant documentation]. Figure 1 The method includes:
[0032] S1. Mix the iron tailings, desulfurization ash and water evenly to obtain a mixture;
[0033] S2. Press the mixture into shape and control the process parameters of the pressing to obtain a cured body.
[0034] The purpose of mixing iron tailings, desulfurization ash, and water evenly in step S1 is to produce a stockpile-friendly solidified body through the cementing and aggregate effects of iron tailings and the solidifying agent desulfurization ash during the solidified body production process.
[0035] The hydration hardening principle of the solidified body in this application is as follows: Tailings contain aluminosilicate minerals with numerous broken silicon-oxygen and aluminum-oxygen bonds on their surfaces. In a cementitious material system with a low calcium-to-silicon ratio and a low water-to-cement ratio, the activity of these bonds is activated by the double salt effect and the tetracoordination effect of silicon. The broken silicon-oxygen and aluminum-oxygen bonds on the surface re-bond, forming a relinked silicon (aluminum)-oxygen tetrahedron. This results in a solidified body with good strength properties.
[0036] In some embodiments, the iron tailings comprise 50% to 90% by mass fraction, the desulfurization ash comprises 10% to 50%, and the concentration of the mixture comprises 80% to 92%.
[0037] The concentration of the mixture is the ratio of the sum of the dry mass of iron tailings and desulfurization ash to the sum of the masses of iron tailings, desulfurization ash, and water, i.e., m(iron tailings + desulfurization ash) / m(iron tailings + desulfurization ash + water). The positive effects of controlling the mass fraction of iron tailings to 50%–90%, the mass fraction of desulfurization ash to 10%–50%, and the concentration of the mixture to 80%–92% are as follows: Within these ranges, a solidified body with high strength is obtained, suitable for safe reclamation at various strengths. The mass fraction of the iron tailings can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, etc., the mass fraction of the desulfurization ash can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc., and the concentration of the mixture can be 80%, 82%, 84%, 86%, 88%, 90%, 92%, etc.
[0038] In some embodiments, the iron tailings comprise 60% to 90% by mass fraction, the desulfurization ash comprises 10% to 40%, and the concentration of the mixture comprises 80% to 90%.
[0039] The mass fraction of the iron tailings can be 60%, 65%, 70%, 75%, 80%, 85%, 90%, etc., the mass fraction of the desulfurization ash can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, etc., and the concentration of the mixture can be 80%, 82%, 84%, 86%, 88%, 90%, etc.
[0040] In some embodiments, the process parameters for compression molding include molding pressure and holding time; wherein,
[0041] The molding pressure can be 10MPa to 40MPa, and the holding time can be 20s to 60s.
[0042] The positive effects of controlling the molding pressure to 10MPa–40MPa and the holding time to 20s–60s: Within this range, a solidified body with high strength is obtained, suitable for safe reclamation at various strengths. The molding pressure can be 10MPa, 15MPa, 20MPa, 25MPa, 30MPa, 35MPa, 40MPa, etc., and the holding time can be 20s, 25s, 30s, 35s, 40s, 45s, 50s, 55s, 60s, etc.
[0043] In some embodiments, the molding pressure is 20MPa to 40MPa, and the holding time is 20s to 40s.
[0044] The molding pressure can be 20MPa, 25MPa, 30MPa, 35MPa, 40MPa, etc., and the holding time can be 20s, 25s, 30s, 35s, 40s, etc.
[0045] In some embodiments, the fineness modulus of the iron tailings is ≤0.8.
[0046] The fineness modulus of iron tailings can be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, etc.
[0047] In some embodiments, the iron tailings are magnetite-quartzite type iron tailings.
[0048] In some embodiments, the desulfurization ash is a byproduct of flue gas desulfurization.
[0049] The byproducts of flue gas desulfurization are reddish-brown powders composed of desulfurization reaction products, unreacted desulfurizing agents, desulfurization products, and fly ash, with relatively fine particle size. Solidification of iron tailings utilizes only low-cost or even zero-cost desulfurization ash, reducing costs by more than 90% compared to traditional solidification methods that primarily use cement. This effectively lowers production costs and is beneficial for solidification of large-volume tailings.
[0050] In some embodiments, the desulfurization ash meets at least one of the following specifications: particle size D90 of 20μm to 40μm, and specific surface area of 500m². 2 / kg~800m 2 / kg.
[0051] The particle size (D90) of desulfurization ash can be 20μm, 25μm, 30μm, 35μm, 40μm, etc. The specific surface area of the desulfurization ash can be 500m². 2 / kg, 550m 2 / kg, 600m 2 / kg, 650m 2 / kg, 700m 2 / kg, 750m 2 / kg, 800m 2 / kg, etc.
[0052] In some embodiments, the method further includes curing the solidified body.
[0053] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.
[0054] The desulfurization ash used in the following examples and comparative examples was commercially available, and the iron tailings were selected from the Shougang Mining Water Plant Iron Mine. Its chemical composition analysis is shown in Table 1, and the particle size sieving results are shown in Table 2. The fineness modulus is 0.4.
[0055] Table 1 Chemical composition of iron tailings (wt / %)
[0056] Element <![CDATA[SiO2]]> <![CDATA[Fe2O3]]> <![CDATA[Al2O3]]> CaO MgO <![CDATA[K2O]]> <![CDATA[Na2O]]> <![CDATA[SO3]]> <![CDATA[TiO2]]> MnO content 69.30 9.60 6.56 6.31 4.16 1.83 0.88 0.45 0.33 0.21
[0057] Table 2. Fineness Screening of Iron Tailings from Shougang Water Plant Iron Mine
[0058] Particle size (mm) percentage Cumulative screening residue +4.75 0 0 2.36～4.75 0 0 1.18～2.36 0 0 0.6～1.18 0.14％ 0.14％ 0.3～0.6 6.06％ 6.20％ 0.15～0.3 27.50％ 33.70％ 0.075～0.15 39.85％ 73.54％ -0.075 26.46％ 100.00％
[0059] Example 1
[0060] This embodiment provides a method for solidification treatment of iron tailings, as detailed below:
[0061] Iron tailings, desulfurization ash, and water are mixed in the following proportions: iron tailings by mass 80%, desulfurization ash by mass 20%, and the mixture concentration is 86%. The three are mixed evenly to obtain a mixture. A molding pressure of 40 MPa is applied to the mixture, and the pressure holding time is 40 seconds. After molding, the solidified body is cured under standard conditions.
[0062] Example 2
[0063] This embodiment provides a method for solidification treatment of iron tailings, as detailed below:
[0064] Iron tailings, desulfurization ash, and water are mixed in the following proportions: the mass fraction of iron tailings is 70%, the mass fraction of desulfurization ash is 30%, and the concentration of the mixture is 86%. The three are mixed evenly to obtain a mixture. A molding pressure of 20 MPa is applied to the mixture, and the pressure holding time is 40 seconds. After molding, the solidified body is cured under standard conditions.
[0065] Example 3
[0066] This embodiment provides a method for solidification treatment of iron tailings, as detailed below:
[0067] Iron tailings, desulfurization ash, and water are mixed in the following proportions: the mass fraction of iron tailings is 60%, the mass fraction of desulfurization ash is 40%, and the concentration of the mixture is 86%. The three are mixed evenly to obtain a mixture. A molding pressure of 20 MPa is applied to the mixture, and the pressure holding time is 40 seconds. After molding, the solidified body is cured under standard conditions.
[0068] Comparative Example 1
[0069] This embodiment provides a method for solidification treatment of iron tailings, as detailed below:
[0070] Iron tailings, desulfurization ash, and water are mixed in the following proportions: iron tailings by mass fraction is 95%, desulfurization ash by mass fraction is 5%, and the concentration of the mixture is 86%. The three are mixed evenly to obtain a mixture. A molding pressure of 20 MPa is applied to the mixture, and the pressure holding time is 40 seconds. After molding, the solidified body is cured under standard conditions.
[0071] Comparative Example 2
[0072] This embodiment provides a method for solidification treatment of iron tailings, as detailed below:
[0073] Iron tailings, desulfurization ash, and water are mixed in the following proportions: iron tailings by mass 50%, desulfurization ash by mass 50%, and mixture concentration 70%. The three are mixed evenly to obtain a mixture. A molding pressure of 20 MPa is applied to the mixture, and a holding time of 40 seconds is applied. After molding, the solidified body is cured under standard conditions.
[0074] Comparative Example 3
[0075] This embodiment provides a method for solidification treatment of iron tailings, as detailed below:
[0076] Iron tailings, desulfurization ash, and water are mixed in the following proportions: the mass fraction of iron tailings is 70%, the mass fraction of desulfurization ash is 30%, and the concentration of the mixture is 86%. The three are mixed evenly to obtain a mixture. A molding pressure of 5 MPa is applied to the mixture, and the pressure holding time is 10 seconds. After molding, the solidified body is cured under standard conditions.
[0077] The experimental results are shown in Table 3:
[0078] Table 3 shows the compressive strength of the cured bodies at different ages obtained from the examples and comparative examples.
[0079]
[0080]
[0081] Table 3 shows that a cured body with high strength is obtained by using the method provided in the embodiments of this application.
[0082] In Comparative Example 1, the mass fraction of iron tailings was too high; in Comparative Example 2, the concentration of the mixture was too low; and in Comparative Example 3, the molding pressure and holding time were too short. The resulting solidified bodies had poor strength.
[0083] Using the iron tailings solidification treatment method described in this application, a 15m×30m×10m solidified body was prepared to replace the topsoil. Winter wheat seeds were then sown on the surface of the solidified body and the slope before covering it with a film. The solidified body was stable, and the wheat grew well. This indicates that the solidified ultrafine iron tailings, after being solidified by desulfurization ash, can prevent damage from rain and wind, and as topsoil, it has the ability to support vegetation growth, making it suitable for safe reclamation at various intensities. This technology has broad demonstration significance and promising prospects for widespread application in the domestic industry.
[0084] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A method for solidifying iron tailings, characterized in that, The method includes: Iron tailings, desulfurization ash and water are mixed evenly to obtain a mixture; The mixture is pressed into shape, and the process parameters of the pressing are controlled to obtain a cured body; By mass fraction, the iron tailings are 60%~80%, the desulfurization ash is 10%~40%, and the concentration of the mixture is 80%~90%; the concentration of the mixture is the ratio of the sum of the dry mass of the iron tailings and desulfurization ash to the sum of the mass of the iron tailings, desulfurization ash and water. The pressing process parameters include pressing pressure and holding time; wherein, The molding pressure is 10 MPa to 40 MPa, and the holding time is 20 s to 60 s; The fineness modulus of the iron tailings is ≤0.8; The iron tailings are magnetite-quartzite type iron tailings; The desulfurization ash is a byproduct of flue gas desulfurization; The desulfurization ash meets at least one of the following specifications: particle size D90 of 20 μm to 40 μm, and specific surface area of 500 m². 2 / kg~800 m 2 / kg.
2. The method according to claim 1, characterized in that, The molding pressure is 20 MPa to 40 MPa, and the holding time is 20 s to 40 s.
3. The method according to claim 1, characterized in that, The method further includes curing the solidified body.