Method for preparing silicon fertilizer by using high-silicon iron tailings

Abstract

The application provides a method for preparing silicon fertilizer by using high-silicon iron tailings, and belongs to the technical field of mining engineering. The high-silicon iron tailing powder is mixed with a calcium-containing activator and an alkaline activator solution, and is subjected to ultrasonic treatment to obtain a mixture, and the mixture is subjected to hydrothermal reaction, and is subjected to drying treatment after the hydrothermal reaction is completed, so as to obtain the silicon fertilizer. The method for preparing the silicon fertilizer by using the high-silicon iron tailings is simple, and the cost is low. The method can effectively realize the recycling of the iron tailings, reduces the environmental pressure, reduces the harm of the iron tailings, realizes the efficient resource utilization of the iron tailings, and the effective silicon content in the prepared silicon fertilizer is 20-31%, so that the silicon fertilizer can be used as a fertilizer to provide nutrients, and can be used as a soil conditioner to improve the soil.

Description

Technical Field

[0001] This invention belongs to the field of mining engineering technology, and in particular relates to a method for preparing silicon fertilizer using high-silicon iron tailings. Background Technology

[0002] Iron tailings are solid waste generated after iron ore beneficiation. Globally, over 10 billion tons of iron tailings and waste rock are discharged annually. These stockpiled tailings not only occupy vast amounts of land resources but also cause severe environmental pollution. Chemical residues from ore beneficiation processes seep into the soil over time and with rainwater runoff, leading to soil pollution, degradation of agricultural functions, and vegetation death. They require substantial resources for maintenance and pose significant safety hazards. Therefore, the resource utilization of iron tailings is imperative.

[0003] Plants can obtain silicon from the soil, but silicon has very low solubility in soil; only ionic or molecular silicic acid dissolved in water can be absorbed by plants. With the rapid development of agriculture in recent years, relying solely on existing available silicon in the soil to provide crops with the necessary silicon nutrients is no longer sufficient for modern agricultural production. Existing research has found that iron tailings contain trace elements such as Si, Fe, Ca, Mg, Mn, and Zn, which are essential for plant growth and development. Furthermore, iron tailings contain a large amount of SiO2. Therefore, developing silicon fertilizer from iron tailings can not only achieve efficient utilization of iron tailings but also solve the problem of silicon deficiency in plants. Summary of the Invention

[0004] In response to the problems of large stockpiles of iron tailings, environmental pollution, and low utilization rate, this invention proposes a method for preparing silicon fertilizer from high-silicon iron tailings. This invention utilizes iron tailings as a resource to synthesize a silicon fertilizer that can be absorbed and utilized by plants. This not only alleviates environmental pressure and reduces the harm caused by iron tailings, but also realizes the resource utilization of iron tailings, bringing certain economic benefits.

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

[0006] This invention proposes a method for preparing silicon fertilizer using high-silicon iron tailings, comprising the following steps:

[0007] High-silicon iron tailings powder is mixed with a solution containing calcium activator and alkaline activator, and ultrasonically treated to obtain a mixture. The mixture is then subjected to hydrothermal reaction, and dried after the hydrothermal reaction is completed to obtain silicon fertilizer.

[0008] Furthermore, the SiO2 content in the high-silicon iron tailings powder is 40-70%.

[0009] Furthermore, the mass ratio of the high-silicon iron tailings powder to the calcium-containing activator is 1:(0.5-1.5), and the mass ratio of the alkaline activator solution to the calcium-containing activator is 1:(1-3).

[0010] Furthermore, the calcium-containing activator includes one or more of calcium oxide, calcium hydroxide, calcium carbonate, and calcium peroxide. Calcium-containing activators are alkaline and are an important component of calcium fertilizers. For example, calcium hydroxide can react with SiO2 under specific conditions to generate corresponding calcium silicate compounds, which are also important components of silicon fertilizers. The use of calcium-containing activators can accelerate the preparation process of silicon fertilizers and can also serve as a raw material for their production.

[0011] Further, the alkaline activator solution includes one or more of potassium hydroxide solution, sodium hydroxide solution, sodium carbonate solution, sodium bicarbonate solution, sodium phosphate solution, and ammonia water. The strong alkalinity of the alkaline activator can break the Si-O bonds in SiO2, the main component of iron tailings powder, converting it into the corresponding Si-OH structure, generating the corresponding silicate, which is the main component of silicon fertilizer. Further, the ultrasonic treatment uses an ultrasonic frequency of 20–40 kHz and an ultrasonic time of 5–20 min.

[0012] This invention employs ultrasonic treatment. During propagation, ultrasound induces cavitation, causing microbubbles to burst and generate shock waves and strong jets. This impacts and damages the surface of iron tailings, promoting the development of surface pores and fissures, and creating new reaction interfaces. When iron tailings are soaked in calcium-containing activators and alkaline activators, solids are generated during the reaction, covering the tailings surface. The cavitation, impact, and microjet effects of ultrasound can create surface erosion spots and boundary layer voids on the boundary layer and particle surfaces, reducing the boundary layer thickness and increasing the interfacial reaction area. This effectively reduces the adverse effects of the covering and encapsulation of insoluble minerals. Ultrasonic waves can destroy the surface coverings of minerals, breaking down mineral particles and increasing the contact area between the minerals and the calcium-containing activators and alkaline activators, exposing fresh surfaces. Furthermore, ultrasonic waves can widen chemical reaction channels, accelerate chemical reaction rates, enhance mass transfer processes, shorten the time of subsequent hydrothermal reactions, and save energy.

[0013] Furthermore, the hydrothermal reaction temperature is 130–190°C, and the reaction time is 0.5–9 h. During this reaction, SiO2 and OH in the iron tailings... - The reaction produces silicates, silicon dioxide and OH. -The reaction to form silicates is an entropy-increasing reaction, with ΔS > 0. Increasing the reaction temperature can drive the reaction in the forward direction, increasing the reaction rate. A hydrothermal reactor setup can provide a closed environment for the reaction, preventing water evaporation and maintaining OH-. - There is enough water to diffuse to the surface of the iron tailings during the reaction.

[0014] Furthermore, the drying temperature is 100–120°C. Using this drying temperature removes free water from the silicon fertilizer, making it easier to store and transport. While hydrated water in the silicon fertilizer requires a higher temperature to remove, it also facilitates better hydration and therefore does not need to be removed. This invention also proposes a silicon fertilizer prepared by the above method.

[0015] Compared with the prior art, the present invention has the following advantages and technical effects:

[0016] (1) The method of producing silicon fertilizer from high-silicon iron tailings is simple and low-cost. It can effectively realize the recycling of iron tailings, reduce environmental pressure, reduce the harm of iron tailings, and achieve efficient resource utilization of iron tailings.

[0017] (2) The silicon fertilizer prepared by the method of the present invention has an effective silicon content of 20-31%, which can be used as fertilizer to provide nutrients and as a soil conditioner to improve the soil. It has certain economic value and can bring economic benefits to enterprises. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0019] Figure 1 This is a flowchart of the silicon fertilizer preparation process in Example 1 of the present invention;

[0020] Figure 2 The image shows the XRD pattern of the silicon fertilizer prepared in Example 1 of this invention.

[0021] Figure 3 SEM image (50 μm) of the high-silicon iron tailings powder used in the embodiments of the present invention;

[0022] Figure 4 SEM image (20 μm) of the high-silicon iron tailings powder used in the embodiments of the present invention;

[0023] Figure 5 SEM image (50 μm) of the silicon fertilizer prepared in Example 1 of this invention;

[0024] Figure 6SEM image (20 μm) of the silicon fertilizer prepared in Example 1 of this invention;

[0025] Figure 7 Photos of potted plants in the experimental group (applied with the silicon fertilizer of Example 3 of this invention) before and after application;

[0026] Figure 8 Photos of potted plants before and after applying silicon fertilizer, serving as the control group (without silicon fertilizer). Detailed Implementation

[0027] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0028] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0029] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0030] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0031] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0032] This invention provides a method for preparing silicon fertilizer using high-silicon iron tailings, comprising the following steps:

[0033] High-silicon iron tailings powder is mixed with calcium-containing activator and alkaline activator, and ultrasonically treated to obtain a mixture. The mixture is then subjected to hydrothermal reaction, and dried after the hydrothermal reaction is completed to obtain silicon fertilizer.

[0034] In a preferred embodiment of the present invention, the SiO2 content in the high-silicon iron tailings powder is 40-70%.

[0035] In a preferred embodiment of the present invention, the mass ratio of the high-silicon iron tailings powder to the calcium-containing activator is 1:(0-1.5), and the mass ratio of the alkaline activator to the calcium-containing activator is 1:(1-2.5).

[0036] In a preferred embodiment of the present invention, the calcium-containing activator includes one or more of calcium oxide, calcium hydroxide, calcium carbonate, and calcium peroxide.

[0037] In a preferred embodiment of the present invention, the alkaline activator includes one or more of potassium hydroxide, sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium phosphate, and ammonia water.

[0038] If the ultrasonic frequency is too low, the impact damage to the surface of the iron tailings is minimal, and the development rate of pores and cracks on the solid surface of the iron tailings is slow. If the ultrasonic frequency is too high, the ultrasonic treatment conditions for iron tailings have already reached their limit, and further changes in the ultrasonic frequency will not have a significant impact on the effective silicon content. If the ultrasonic treatment time is too long, the ultrasonic treatment time for iron tailings has already reached its limit, and further changes in the time will not have a significant impact on the effective silicon content, increasing production costs. If the time is too short, the impact damage to the surface of the iron tailings is short, the mineral crushing effect is poor, and the effective silicon content in the product is low. Based on this, in the preferred embodiment of the present invention, the ultrasonic frequency of the ultrasonic treatment is 20-40 kHz, and the ultrasonic time is 5-20 min.

[0039] If the temperature is too low, the reaction rate will be too low, resulting in a low effective silicon content in the product; if the temperature is too high, the small amount of Al2O3 contained in the iron tailings will react with sodium hydroxide and SiO2 to form hydrated sodium aluminosilicate precipitate, reducing the effective silicon content in the product. If the reaction time is too short, the reaction will not proceed fully, resulting in a low effective silicon content in the product; if the reaction time is too long, the effective silicon content will not increase much, but will instead increase production costs. Based on this, in the preferred embodiment of the present invention, the hydrothermal reaction temperature is 130-190°C, and the reaction time is 0.5-9 hours.

[0040] At normal pressure, the boiling point of water is 100℃. If the drying temperature is too low, the free water in the silicon fertilizer will take a long time to be removed; if the temperature is too high, the hydrated water in the silicon fertilizer may be removed, thus reducing the hydration capacity of the silicon fertilizer. Based on this, in a preferred embodiment of the present invention, the drying temperature is 100-120℃.

[0041] The high-silicon iron tailings used in this embodiment of the invention originated from a magnetite beneficiation plant in Tangshan. The main mineral components were quartz, anorthite, kaolinite, and montmorillonite, with an average particle size of 22.33 μm and a SiO2 content of 65.70%. The contents of copper, cadmium, lead, chromium, and nickel in the high-silicon iron tailings were detected using an atomic absorption spectrophotometer, and the contents of arsenic and mercury in the samples were detected using an atomic fluorescence spectrophotometer. Heavy metal detection was performed according to the test methods in HJ 702-2014 "Determination of Mercury, Arsenic, Selenium, Bismuth and Antimony in Solid Waste - Microwave Digestion / Atomic Fluorescence Method" and GB 5085.3-2007 "Identification Standard for Hazardous Waste - Leaching Toxicity Identification". The detection results are shown in Table 1.

[0042] Table 1. Results of heavy metal content determination in high-silicon iron tailings

[0043] Element copper cadmium lead chromium nickel arsenic mercury Content (mg / L) 0.03100 0.00713 0.00656 0.07000 0.05500 0.00021 0.00006 Detection limit (mg / L) 0.02000 0.00500 0.00500 0.05000 0.04000 0.00010 0.00002 Standard mg / L 100.00000 1.00000 5.00000 5.00000 5.00000 5.00000 0.10000

[0044] As can be seen from Table 1, the concentrations of heavy metal elements copper, cadmium, lead, chromium, nickel, arsenic, and mercury in the leaching solution of the iron tailings sample used in the embodiments of the present invention are low, all below the concentration limits of hazardous components in leaching solution in GB 5085.3-2007 "Identification Standard for Hazardous Waste - Leaching Toxicity Identification". Therefore, the iron tailings sample is determined not to be a hazardous solid waste with leaching toxicity characteristics, and can therefore be further processed into silicon fertilizer and applied to the soil.

[0045] All other raw materials used in the embodiments of this invention were obtained through commercial purchase.

[0046] The technical solution of the present invention will be further illustrated by the following embodiments.

[0047] Example 1

[0048] High-silicon iron tailings powder was added to a calcium-containing activator (calcium carbonate, with a mass ratio of high-silicon iron tailings powder to calcium-containing activator of 1:1) to obtain mixture 1. Then, an alkaline activator solution (sodium hydroxide, mass concentration 32%, with a mass ratio of alkaline activator solution to calcium-containing activator of 1:1.25) was added to obtain mixture 2. The mixture was then ultrasonically treated in a 25 kHz ultrasonic instrument for 10 min to obtain mixture 3. This mixture was transferred to a 1 L hydrothermal reactor and hydrothermally reacted at 170 °C for 2 h. After the hydrothermal reaction, the sample was removed and dried in a 120 °C oven until the product agglomerated and free of free water, thus obtaining silicon fertilizer. The silicon fertilizer preparation flow chart of Example 1 of this invention is shown below. Figure 1 .

[0049] The available silicon in the prepared silicon fertilizer was determined according to the method for determining available silicon in the silicon fertilizer industry standard NY / T 797-2004. The specific test method is as follows:

[0050] Weigh 0.2 g of the sample, accurate to 0.0001 g, and place it in a 250 mL PTFE beaker. Add 15 mL of 36% hydrochloric acid and 5 mL of 68% nitric acid sequentially. Place the beaker on a preheated hot plate and shake every 5 minutes until the sample is completely dissolved. After complete dissolution, rinse the beaker walls and add 2 mL of 40% hydrofluoric acid. Continue heating in 80°C water for 30 minutes to ensure complete dissolution. Then, add 10 mL of 68% nitric acid and 2.000 g of potassium chloride. Cool the beaker in cold water for at least 30 minutes until it reaches room temperature. Filter the solution using a polyethylene funnel and rapid qualitative filter paper. Wash the beaker and precipitate 3-4 times with saturated potassium chloride-ethanol washing solution. Transfer the precipitate, along with the pulp and sponge, to the original polytetrafluoroethylene beaker. Add 10 mL of potassium chloride-ethanol solution and 1 mL of 1% phenolphthalein indicator. Neutralize any remaining acid with sodium hydroxide solution. Gently squeeze the filter paper and allow it to stand until the phenolphthalein turns red and does not fade. Add 10 mL of boiling distilled water and immediately titrate with 0.5 mol / L sodium hydroxide standard solution. The endpoint is reached when the solution in the beaker turns a faint red color, and the faint red color does not disappear with continuous stirring.

[0051] The effective silicon content is calculated according to formula (1):

[0052] SiO2 (%) = (C 氢氧化钠 V 氢氧化钠 ×0.015) / m×100% Equation (1)

[0053] In the formula, C is the concentration of sodium hydroxide standard solution, mol / L; V is the volume of sodium hydroxide standard solution consumed, mL; and m is the mass of the sample weighed, g.

[0054] The effective silicon content of the silicon fertilizer prepared in Example 1 of the present invention was calculated to be 29.62% according to the above method.

[0055] The XRD pattern of the silicon fertilizer prepared in Example 1 of this invention is shown in the figure. Figure 2 ,Depend on Figure 2 It can be seen that the main components of the silicon fertilizer sample prepared in Example 1 of the present invention are CaSiO3, Ca2SiO4, Ca3SiO5 and SiO2.

[0056] Figure 3 and Figure 4 This is a SEM image of the high-silicon iron tailings powder used in Example 1 of the present invention. Figure 5 and Figure 6 The image shown is a SEM image of the silicon fertilizer prepared in Example 1 of this invention, for comparison. Figures 3-6It can be seen that the structure of high-silicon iron tailings powder is distinct with clear boundaries between particles, while the prepared silicon fertilizer has blurred edges and indistinct particle boundaries. The fine particles are all aggregated and adhered together, becoming a porous and loose powder with no amorphous structure.

[0057] Example 2

[0058] High-silicon iron tailings powder was added to a calcium-containing activator (calcium hydroxide, with a mass ratio of high-silicon iron tailings powder to calcium-containing activator of 1:1.5), followed by the addition of an alkaline activator solution (calcium carbonate solution, mass concentration of 10%, with a mass ratio of alkaline activator solution to calcium-containing activator of 1:2.8). The mixture was then ultrasonically treated in a 20 kHz ultrasonic instrument for 8 min. The resulting mixture was transferred to a 1 L hydrothermal reactor and hydrothermally reacted at 150 °C for 7 h. After the hydrothermal reaction was completed, the sample was removed and dried in a 120 °C oven to obtain silicon fertilizer.

[0059] Tests showed that the effective silicon content in the prepared silicon fertilizer was 26.34%.

[0060] Example 3

[0061] High-silicon iron tailings powder was added to a calcium-containing activator (calcium oxide, with a mass ratio of high-silicon iron tailings powder to calcium-containing activator of 1:1), followed by the addition of an alkaline activator solution (sodium hydroxide solution, mass concentration of 35%, with a mass ratio of alkaline activator solution to calcium-containing activator of 1:1.6). The mixture was then ultrasonically treated in a 10 kHz ultrasonic instrument for 15 min. The resulting mixture was transferred to a 1 L hydrothermal reactor and hydrothermally reacted at 170 °C for 4 h. After the hydrothermal reaction was completed, the sample was removed and dried in a 120 °C oven to obtain silicon fertilizer.

[0062] Tests showed that the effective silicon content in the prepared silicon fertilizer was 30.67%.

[0063] Example 4

[0064] High-silicon iron tailings powder was added to a calcium-containing activator (calcium peroxide, with a mass ratio of high-silicon iron tailings powder to calcium-containing activator of 1:0.5), followed by the addition of an alkaline activator solution (potassium hydroxide and ammonia water in a volume ratio of 1:1, both with a mass concentration of 20%, and a mass ratio of alkaline activator solution to calcium-containing activator of 1:2.5). The mixture was then ultrasonically treated in a 40 kHz ultrasonic instrument for 20 min. The resulting mixture was transferred to a 1 L hydrothermal reactor and hydrothermally reacted at 130 °C for 9 h. After the hydrothermal reaction was completed, the sample was removed and dried in a 100 °C oven to obtain silicon fertilizer.

[0065] Tests showed that the effective silicon content in the prepared silicon fertilizer was 17.47%.

[0066] Example 5

[0067] High-silicon iron tailings powder was added to a calcium-containing activator (calcium carbonate, with a mass ratio of high-silicon iron tailings powder to calcium-containing activator of 1:1), followed by the addition of an alkaline activator solution (sodium bicarbonate solution, mass concentration of 10%, with a mass ratio of alkaline activator solution to calcium-containing activator of 1:1). The mixture was then ultrasonically treated in a 30 kHz ultrasonic instrument for 5 min. The resulting mixture was transferred to a 1 L hydrothermal reactor and hydrothermally reacted at 190 °C for 0.5 h. After the hydrothermal reaction was completed, the sample was removed and dried in an oven at 120 °C to obtain silicon fertilizer.

[0068] Tests showed that the effective silicon content in the prepared silicon fertilizer was 14.2%.

[0069] Comparative Example 1

[0070] Same as Example 3, except that the ultrasonic treatment step is omitted.

[0071] Tests showed that the effective silicon content in the prepared silicon fertilizer was 28.62%.

[0072] Comparative Example 2

[0073] Same as Example 3, except that the hydrothermal reaction was carried out at 250°C for 4 hours.

[0074] Tests showed that the effective silicon content in the prepared silicon fertilizer was 29.85%.

[0075] Comparative Example 3

[0076] Same as Example 3, except that the treatment was performed in an 80kHz ultrasonic instrument for 6 minutes.

[0077] Tests showed that the effective silicon content in the prepared silicon fertilizer was 28.93%.

[0078] Comparative Example 4

[0079] Same as Example 3, except that the step of adding alkaline activator solution is omitted.

[0080] Tests showed that the effective silicon content in the prepared silicon fertilizer was 10.32%.

[0081] Comparative Example 5

[0082] Same as Example 3, except that the step of adding calcium-containing activator is omitted.

[0083] Tests showed that the effective silicon content in the prepared silicon fertilizer was 24.31%.

[0084] Comparing Example 3 with Comparative Examples 1-5, it can be found that the effective silicon content in the silicon fertilizer sample prepared in Example 3 is higher than that in the comparative examples. The reason is:

[0085] The decrease in effective silicon content in Comparative Example 1 is due to the fact that ultrasound can have an impact and damage effect on the surface of iron tailings, promoting the development of pores and cracks on the solid surface of iron tailings and creating new reaction interfaces. Without ultrasound treatment, the effective silicon content will decrease.

[0086] The decrease in effective silicon content in Comparative Example 2 is due to the fact that excessively high reaction temperature causes a small amount of Al2O3 contained in the iron tailings to react with sodium hydroxide and SiO2 to form hydrated sodium aluminosilicate precipitate, resulting in a decrease in effective silicon content in the product.

[0087] The decrease in effective silicon content in Comparative Example 3 is because the ultrasonic treatment conditions for iron tailings have reached their limit, and changing the frequency of the ultrasound will not have a significant impact on the effective silicon content.

[0088] The decrease in effective silicon content in Comparative Example 4 was due to the lack of a basic activator, resulting in a decrease in OH- ions in the solution. - Low ion concentration leads to a slower reaction rate, resulting in a decrease in effective silicon content;

[0089] The decrease in effective silicon content in Comparative Example 5 was due to the lack of calcium-containing activator, low alkali concentration in the reaction, reduced corrosion intensity on the iron tailings surface, and consequently reduced contact area between the iron tailings and the alkali solution, resulting in a decrease in effective silicon content.

[0090] Planting Trial

[0091] Specific planting process: The crop is mint. Every day at a fixed time of 9:00 am, a fixed amount of water of 100mL is applied. The left side shows watering with silicon fertilizer prepared in Example 3, and the right side shows watering only.

[0092] After 22 days of cultivation, photos of the potted plants in the experimental group (treated with the silicon fertilizer of Example 3 of this invention) before and after application are shown below. Figure 6 Photos of potted plants in the control group (without silicon fertilizer) before and after application are shown below. Figure 7 .

[0093] The soil bulk density and porosity of the flowerpots in the experimental and control groups were measured according to the industry standard NY / T 1121.4-2006 "Soil Testing - Determination of Soil Bulk Density". The results showed that after applying the silicon fertilizer of Example 3 of this invention, when the amount of silicon fertilizer applied was 25%, the soil bulk density was 1.403 g / cm³. 3At this point, the soil density is moderate, suitable for crop growth; the soil porosity reaches 53.552%, improving soil aeration; it reduces soil shear strength, decreases soil cohesion, and lowers soil tillage resistance. Compared with the control group, it significantly improves soil structure and has certain economic value.

[0094] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing silicon fertilizer using high-silicon iron tailings, characterized in that, Includes the following steps: High-silicon iron tailings powder is mixed with a solution containing calcium activator and alkaline activator, and ultrasonically treated to obtain a mixture. The mixture is then subjected to hydrothermal reaction, and dried after the hydrothermal reaction is completed to obtain silicon fertilizer. The ultrasonic frequency of the ultrasonic treatment is 10-40 kHz, and the ultrasonic time is 5-20 min. The hydrothermal reaction temperature is 130–190℃, and the reaction time is 0.5–9 h; The mass ratio of the high-silicon iron tailings powder to the calcium-containing activator is 1:(0.5-1.5), and the mass ratio of the alkaline activator solution to the calcium-containing activator is 1:(1-3).

2. The method for preparing silicon fertilizer from high-silicon iron tailings according to claim 1, characterized in that, The SiO2 content in the high-silicon iron tailings powder is 40-70%.

3. The method for preparing silicon fertilizer from high-silicon iron tailings according to claim 1, characterized in that, The calcium-containing activator includes one or more of calcium oxide, calcium hydroxide, calcium carbonate, and calcium peroxide.

4. The method for preparing silicon fertilizer from high-silicon iron tailings according to claim 1, characterized in that, The alkaline activator solution includes one or more of potassium hydroxide solution, sodium hydroxide solution, sodium carbonate solution, sodium bicarbonate solution, sodium phosphate solution, and ammonia water.

5. The method for preparing silicon fertilizer from high-silicon iron tailings according to claim 1, characterized in that, The drying process is carried out at a temperature of 100–120°C.

6. A silicon fertilizer prepared by the method according to any one of claims 1 to 5.

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