Phosphogypsum-based vegetation concrete and preparation method thereof
By using phosphogypsum-based vegetation concrete, which utilizes industrial solid waste such as red mud and phosphogypsum as raw materials, and combines slow-release fertilizer granules and cementing materials, a three-in-one slow-release synergistic system is formed. This solves the problems of low nutrient utilization and high cost of traditional fertilizers in the ecological restoration of abandoned mines, and achieves long-term fertilization effect and environmentally friendly ecological restoration.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG UNIV
- Filing Date
- 2026-03-12
- Publication Date
- 2026-05-12
AI Technical Summary
Traditional fertilizers have problems such as low nutrient utilization, high cost, release rate that is easily affected by the environment and microplastic pollution in the ecological restoration of abandoned mines, and slow-release fertilizers have limitations in terms of applicability and cost.
Using phosphogypsum-based plant concrete, industrial solid waste such as red mud and phosphogypsum are used as raw materials. Combined with slow-release fertilizer granules and cementing materials, a three-in-one slow-release synergistic system is formed. Nutrient release is controlled through the microporous structure of the cementing materials and the sodium alginate gel network to achieve long-term fertilization effect.
It enables the resource utilization of industrial solid waste, reduces material costs by more than 40%, solves the high cost problem of traditional slow-release fertilizers, and promotes long-term plant growth by precisely controlling nutrient release, thus avoiding nutrient loss and environmental pollution.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of building materials technology, and in particular relates to a phosphogypsum-based planted concrete and its preparation method. Background Technology
[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.
[0003] The exploitation of mineral resources has led to the emergence of numerous abandoned mines. Ecological restoration methods for abandoned mines mainly include backfilling with topsoil and adding organic fertilizers. This involves removing polluted or infertile original soil and replacing it with fertile topsoil from external sources, supplemented with straw, livestock manure, and biogas residue, to rapidly rebuild the soil matrix and achieve rapid recovery of plants and other organisms. Traditional fertilizers, due to their high solubility and rapid release, suffer from low nutrient utilization rates. Only a small amount of nutrients are absorbed and utilized by plants, while most other nutrients are lost through leaching and volatilization, entering the aquatic environment and ultimately causing environmental problems such as eutrophication of soil and water bodies.
[0004] Slow-release fertilizers have significant advantages such as high nutrient utilization, economic efficiency, environmental friendliness, strong adaptability, and eco-friendliness. However, they still have disadvantages such as higher cost (30% to 50% more expensive than traditional fertilizers), release rate that is easily affected by temperature and humidity, and some coating materials that are difficult to degrade. At the same time, their crop compatibility and soil applicability are also limited, which may lead to problems such as microplastic pollution or uneven nutrient release.
[0005] How to develop slow-release fertilizers based on solid waste resources from abandoned mines and apply them to the ecological restoration of abandoned mines is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention
[0006] Based on the current state of technology, the purpose of this invention is to provide a phosphogypsum-based vegetation concrete and its preparation method. The phosphogypsum-based fertilizer-slow-release vegetation concrete, prepared from industrial solid waste as raw material, includes solid waste-based cementitious materials, artificial aggregates, and slow-release fertilizer. This not only realizes the resource utilization of industrial solid waste but also significantly reduces material costs.
[0007] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention provides a phosphogypsum-based planted concrete, comprising, by weight, 112-175 parts of cementitious material, 190-270 parts of aggregate, and 75-110 parts of slow-release fertilizer granules. The cementitious materials include 60-80 parts red mud, 20-40 parts mineral powder, 30-40 parts water, and 2-5 parts ammonium dihydrogen phosphate; the raw materials for the aggregates include 150-200 parts phosphogypsum, 10-20 parts cement, 10-20 parts mineral powder, and 20-25 parts silica fume; the raw materials for the slow-release fertilizer granules include 40-50 parts phosphogypsum, 20-30 parts wood ash, 10-15 parts sodium alginate, and 8-12 parts water.
[0008] A second aspect of the present invention provides a method for preparing the above-mentioned phosphogypsum-based planted concrete, comprising the following steps: S1. After dry mixing the red mud and mineral powder in the raw materials of the cementitious material, add water and ammonium dihydrogen phosphate and stir to obtain the cementitious material; S2. The phosphogypsum, cement, mineral powder and silica fume in the raw materials of the aggregate are dry-mixed and then granulated to obtain the aggregate; S3. Mix and stir the phosphogypsum, wood ash and sodium alginate in the slow-release fertilizer granules. Spray water during the mixing process. Then granulate the moistened mixture and dry it to obtain slow-release fertilizer granules. S4. Mix and stir the cementitious materials, aggregates and slow-release fertilizer particles to obtain the phosphogypsum-based planted concrete.
[0009] The beneficial effects of this invention are as follows: The phosphogypsum-based plant concrete provided by this invention constructs a three-in-one slow-release synergistic system of "cementing material-slow-release fertilizer-aggregate": the high porosity structure of the cementing material provides channels for nutrient diffusion, the slow-release fertilizer particles encapsulated by sodium alginate precisely control the nutrient release rate (50-70 days), and the phosphogypsum aggregate adsorbs some nutrients through its own micropores, further delaying nutrient release and avoiding the problems of "sudden nutrient release" or "release interruption" in traditional technologies, thus achieving the effect of promoting plant growth in the long term.
[0010] In cementitious materials, the alkaline components of red mud activate mineral powder, dissolving Si-O and Al-O bonds in the mineral powder and releasing active SiO2 and Al2O3, while Ca... 2+ The reaction with these active components forms C-(A)-SH gel. The intertwined growth of these hydration products hardens the matrix and imparts mechanical properties. The addition of ammonium dihydrogen phosphate neutralizes some of the alkalinity, neither affecting the formation of C-(A)-SH gel nor hindering alkaline stress in plants. While the gelling material does not directly perform the primary slow-release function, it plays a supporting role: the C-(A)-SH gel structure contains numerous micropores with diameters of 2-50 nm. When nutrients (such as phosphorus and potassium ions) released from the slow-release fertilizer particles permeate into the gelling material matrix, some nutrients can be adsorbed by these micropores and slowly released into the surrounding environment through ion exchange.
[0011] The aggregate is made from bulk solid waste such as phosphogypsum and mineral powder, which can reduce the consumption of natural limestone aggregate while disposing of bulk solid waste. The aggregate can regulate the porosity of the vegetation concrete; the larger the aggregate particle size, the greater the porosity of the vegetation concrete, thereby regulating the nutrient release process.
[0012] The slow-release fertilizer granules contain phosphogypsum, which provides abundant phosphorus, sulfur, and calcium, while wood ash provides abundant potassium, phosphorus, and magnesium. A three-dimensional gel network formed by sodium alginate encapsulates the phosphogypsum and wood ash, controlling nutrient release through the physical barrier and ion exchange effect of the sodium alginate gel layer. After application, water gradually permeates the gel layer, allowing the phosphorus, potassium, calcium, and magnesium nutrients to be slowly released through diffusion, ultimately achieving a long-term fertilization effect.
[0013] The phosphogypsum-based planted concrete of this invention uses industrial solid waste such as red mud and phosphogypsum as core raw materials, realizing the resource utilization of solid waste while reducing material costs by more than 40%, thus solving the contradiction of "high cost and low solid waste disposal" in traditional slow-release fertilizer planted concrete. Detailed Implementation
[0014] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0015] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0016] One or more embodiments of the present invention provide a phosphogypsum-based planted concrete, which, by weight, comprises 112-165 parts of cementitious material, 190-270 parts of aggregate, and 75-110 parts of slow-release fertilizer granules. The cementitious materials include 60-80 parts red mud, 20-40 parts mineral powder, 30-40 parts water, and 2-5 parts ammonium dihydrogen phosphate; the raw materials for the aggregates include 150-200 parts phosphogypsum, 10-20 parts cement, 10-20 parts mineral powder, and 20-25 parts silica fume; the raw materials for the slow-release fertilizer granules include 40-50 parts phosphogypsum, 20-30 parts wood ash, 10-15 parts sodium alginate, and 8-12 parts water.
[0017] In the above components, the cementitious materials and mixing water activate the mineral powder through red mud to generate C-(A)-SH gel, which hardens the planted concrete matrix and gives it mechanical properties. The addition of an appropriate amount of ammonium dihydrogen phosphate neutralizes part of the alkalinity, which neither affects the formation of C-(A)-SH gel nor causes alkaline stress to the plants. The aggregate, which can absorb large amounts of solid waste, can regulate the porosity of the planted concrete through its own particle size, thereby regulating the nutrient release process. The sodium alginate in the slow-release fertilizer granules forms a three-dimensional gel network. As water gradually penetrates into the gel layer, the physical barrier effect and ion exchange effect of the sodium alginate gel network control the nutrient release. After nutrients are released from the slow-release fertilizer granules, the micropores of 2~50nm in the C-(A)-SH gel can also adsorb nutrients (such as phosphorus and potassium ions) and slowly release them into the surrounding environment through ion exchange, thus assisting the slow-release effect. The larger aggregate size makes the porosity of the planted concrete greater, and the micropores of the phosphogypsum aggregate itself can adsorb some nutrients, further delaying the release of nutrients and achieving a long-term fertilization effect.
[0018] Optionally, the aggregate particle size is 15~30mm. Under the premise of constant total aggregate addition, using aggregate with a larger particle size will, on the one hand, form larger pores when stacked due to the increased volume of individual particles, and on the other hand, reduce the total number of aggregate particles, and correspondingly reduce the contact points between particles and the "neck" area formed by the cementitious material slurry, thereby reducing the blocking and segmentation effect of cementitious material on the pores between aggregates.
[0019] Optionally, the slow-release fertilizer granules have a particle size of 1-2 mm. Particles of 1-2 mm have a larger total specific surface area per unit mass, which enhances the contact opportunities between the granules and pore water and plant roots, facilitating a smoother and more continuous release of nutrients. At the same time, although the internal interconnected pore size of the planted concrete is large, there are still a large number of "bottleneck" areas in the pore channels, ranging from millimeters to sub-centimeters. Controlling the particle size of the slow-release fertilizer granules to 1-2 mm ensures that the granules can smoothly enter and stably embed themselves in the pore network during mixing and pouring. This prevents them from easily being lost from large pores and avoids blocking key channels for root extension or water migration due to excessively large particles, thereby ensuring the uniform distribution and functional realization of the material on a macroscopic scale.
[0020] Optionally, the red mud is selected from one or more of Bayer process red mud, sintering process red mud, and combined process red mud.
[0021] Optionally, the mineral powder is selected from one or more of S75 mineral powder, S95 mineral powder and S105 mineral powder.
[0022] Optionally, the phosphogypsum is selected from one or more of dihydrate phosphogypsum, hemihydrate phosphogypsum, and anhydrous phosphogypsum.
[0023] Optionally, the cement is ordinary Portland cement.
[0024] Optionally, the silica fume is micro silica powder with a silica (SiO2) content ≥ 85% and a specific surface area ≥ 15 m² / g, selected from ferrosilicon alloys or dust collected during industrial silicon smelting.
[0025] One or more embodiments of the present invention provide a method for preparing the above-mentioned phosphogypsum-based planted concrete, comprising the following steps: S1. After dry mixing the red mud and mineral powder in the raw materials of the cementitious material, add water and ammonium dihydrogen phosphate and stir to obtain the cementitious material; S2. The phosphogypsum, cement, mineral powder and silica fume in the raw materials of the aggregate are dry-mixed and then granulated to obtain the aggregate; S3. Mix and stir the phosphogypsum, wood ash and sodium alginate in the slow-release fertilizer granules. Spray water during the mixing process. Then granulate the moistened mixture and dry it to obtain slow-release fertilizer granules. S4. Mix and stir the cementitious materials, aggregates and slow-release fertilizer particles to obtain the phosphogypsum-based planted concrete.
[0026] In the above process, aggregates and slow-release fertilizer granules are prepared directly by granulation, without the need for complex steps such as sintering. The preparation method is simple and easy to implement, and is suitable for the construction environment of abandoned mines.
[0027] Optionally, in S1, the dry mixing time is 1~2 minutes and the stirring time is 2~3 minutes.
[0028] Optionally, in S2, the dry mixing time is 3~5 minutes; after granulation by a wet granulator, the granules are cured for more than 1 day; the wet granulation method can obtain spheres with smooth surface and dense structure, with set strength and porosity.
[0029] Optionally, in S3, the mixing time is 1~5 min; the granulation process is carried out in a rolling granulator, the roller inclination angle is adjusted to 2.5°~10°, the rotation speed is set to 20~35 r / min, and the rolling granulation is carried out for 3~10 min to form slow-release fertilizer wet granules with uniform particle size; the drying method is: air drying at 50~60℃ for 30~50 min to obtain dried slow-release fertilizer granules.
[0030] Optionally, in S4, the mixing time is 15~30s, and then the mixture is molded to obtain phosphogypsum-based planted concrete.
[0031] The present invention will be further described below with reference to the embodiments.
[0032] Example 1 A phosphogypsum-based planted concrete, by weight, comprises 132 parts of cementitious material, 200 parts of aggregate, and 78 parts of slow-release fertilizer granules; The cementitious materials include 70 parts red mud, 30 parts mineral powder, 30 parts water and 2 parts ammonium dihydrogen phosphate; the raw materials for the aggregates include 150 parts phosphogypsum, 20 parts cement, 10 parts mineral powder and 20 parts silica fume; the raw materials for the slow-release fertilizer granules include 40 parts phosphogypsum, 20 parts wood ash, 10 parts sodium alginate and 8 parts water.
[0033] The aggregate particle size is 30mm; the slow-release fertilizer granules have a particle size of 1mm.
[0034] The red mud is selected from Bayer process red mud, the mineral powder is selected from S75 mineral powder, the phosphogypsum is selected from dihydrate phosphogypsum, the cement is 32.5 grade ordinary Portland cement, and the silica fume comes from the dust collected during the smelting of ferrosilicon alloys.
[0035] Preparation methods include: S1. After premixing and dry-stirring the red mud and mineral powder in the raw materials of the cementitious material for 60 seconds, add water and ammonium dihydrogen phosphate, and continue stirring for 120 seconds to obtain the cementitious material. S2. After dry mixing the phosphogypsum, cement, mineral powder and silica fume in the raw materials of the aggregate for 3 minutes, the aggregate is granulated by a wet granulator to obtain spheres with smooth surface and dense structure. After curing for 1 day, the aggregate is obtained. S3. Mix the phosphogypsum, wood ash and sodium alginate in the slow-release fertilizer granules for 5 minutes. During the mixing process, spray atomized water evenly through a spraying device. Then, put the moistened mixture into a rolling granulator, adjust the roller inclination angle to 2.5°, set the speed to 20 r / min, and roll and granulate for 3 minutes to form wet slow-release fertilizer granules with uniform particle size. Place the wet slow-release fertilizer granules in a 50℃ ventilated drying equipment and process for 30 minutes to obtain slow-release fertilizer granules. S4. Add the cementitious materials, aggregates and slow-release fertilizer granules into the mixer and mix them at a medium speed for 30 seconds to obtain the phosphogypsum-based planted concrete.
[0036] Example 2 A phosphogypsum-based planted concrete, by weight, comprises 132 parts of cementitious material, 200 parts of aggregate, and 88 parts of slow-release fertilizer granules; The cementitious materials include 70 parts red mud, 30 parts mineral powder, 30 parts water and 2 parts ammonium dihydrogen phosphate; the raw materials for the aggregates include 150 parts phosphogypsum, 20 parts cement, 10 parts mineral powder and 20 parts silica fume; the raw materials for the slow-release fertilizer granules include 40 parts phosphogypsum, 20 parts wood ash, 20 parts sodium alginate and 8 parts water.
[0037] The difference from Example 1 is that the amount of sodium alginate added is increased to 20 parts, while the specifications and preparation methods of other raw materials are the same as in Example 1.
[0038] Example 3 A phosphogypsum-based planted concrete, by weight, comprises 132 parts of cementitious material, 200 parts of aggregate, and 78 parts of slow-release fertilizer granules; The cementitious materials include 70 parts red mud, 30 parts mineral powder, 30 parts water and 2 parts ammonium dihydrogen phosphate; the raw materials for the aggregates include 150 parts phosphogypsum, 20 parts cement, 10 parts mineral powder and 20 parts silica fume; the raw materials for the slow-release fertilizer granules include 40 parts phosphogypsum, 20 parts wood ash, 10 parts sodium alginate and 8 parts water.
[0039] The mass fractions and specifications of each raw material are the same as in Example 1. The difference from Example 1 is that the aggregate spheres obtained during the preparation process have a particle size of 15 mm.
[0040] Example 4 A phosphogypsum-based planted concrete, by weight, comprises 112 parts of cementitious material, 190 parts of aggregate, and 78 parts of slow-release fertilizer granules. The cementitious materials include 60 parts red mud, 20 parts mineral powder, 30 parts water and 2 parts ammonium dihydrogen phosphate; the raw materials for the aggregates include 150 parts phosphogypsum, 10 parts cement, 10 parts mineral powder and 20 parts silica fume; the raw materials for the slow-release fertilizer granules include 40 parts phosphogypsum, 20 parts wood ash, 10 parts sodium alginate and 8 parts water.
[0041] The aggregate particle size is 30mm, and the slow-release fertilizer granules have a particle size of 2mm.
[0042] The red mud is selected from sintered red mud, the mineral powder is selected from S95 mineral powder, the phosphogypsum is selected from hemihydrate phosphogypsum, the cement is 42.5 grade ordinary Portland cement, and the silica fume is selected from the dust collected during the smelting of ferrosilicon alloys.
[0043] Preparation methods include: S1. After premixing and dry-stirring the red mud and mineral powder in the raw materials of the cementitious material for 2 minutes, add water and ammonium dihydrogen phosphate, and continue stirring for 3 minutes to obtain the cementitious material. S2. After dry mixing the phosphogypsum, cement, mineral powder and silica fume in the raw materials of the aggregate for 5 minutes, the aggregate is granulated by a wet granulator to obtain spheres with smooth surface and dense structure. After curing for 1 day, the aggregate is obtained. S3. Mix the phosphogypsum, wood ash and sodium alginate in the slow-release fertilizer granules for 1 minute. During the mixing process, spray atomized water evenly through a spraying device. Then, put the moistened mixture into a rolling granulator, adjust the roller inclination angle to 2.5°, set the speed to 20 r / min, and roll granulate for 10 minutes to form wet slow-release fertilizer granules with uniform particle size. Place the wet slow-release fertilizer granules in a 60℃ ventilated drying equipment and process for 50 minutes to obtain slow-release fertilizer granules. S4. Add the cementitious materials, aggregates and slow-release fertilizer granules into the mixer and mix them at a medium speed for 30 seconds to obtain the phosphogypsum-based planted concrete.
[0044] Example 5 A phosphogypsum-based planted concrete, by weight, comprises 165 parts of cementitious material, 265 parts of aggregate, and 107 parts of slow-release fertilizer granules. The cementitious materials include 80 parts red mud, 40 parts mineral powder, 40 parts water, and 5 parts ammonium dihydrogen phosphate; the raw materials for the aggregates include 200 parts phosphogypsum, 20 parts cement, 20 parts mineral powder, and 25 parts silica fume; the raw materials for the slow-release fertilizer granules include 50 parts phosphogypsum, 30 parts wood ash, 15 parts sodium alginate, and 12 parts water.
[0045] The aggregate particle size is 15mm, and the slow-release fertilizer granules have a particle size of 1mm.
[0046] The red mud is selected from the combined process red mud, the mineral powder is selected from S105 mineral powder, the phosphogypsum is selected from anhydrous phosphogypsum, the cement is 32.5 grade ordinary Portland cement, and the silica fume is selected from the dust collected during the smelting of ferrosilicon alloys.
[0047] Preparation methods include: S1. After premixing and dry-stirring the red mud and mineral powder in the raw materials of the cementitious material for 60 seconds, add water and ammonium dihydrogen phosphate, and continue stirring for 120 seconds to obtain the cementitious material. S2. After dry mixing the phosphogypsum, cement, mineral powder and silica fume in the raw materials of the aggregate for 3 minutes, the aggregate is granulated by a wet granulator to obtain spheres with smooth surface and dense structure. After curing for 1 day, the aggregate is obtained. S3. Mix the phosphogypsum, wood ash and sodium alginate in the slow-release fertilizer granules for 1 minute. During the mixing process, spray atomized water evenly through a spraying device. Then, put the moistened mixture into a rolling granulator, adjust the roller inclination angle to 10°, set the speed to 35 r / min, and roll and granulate for 3 minutes to form wet slow-release fertilizer granules with uniform particle size. Place the wet slow-release fertilizer granules in a 50℃ ventilated drying equipment and process for 30 minutes to obtain slow-release fertilizer granules. S4. Add the cementitious materials, aggregates and slow-release fertilizer granules into the mixer and mix them at a medium speed for 30 seconds to obtain the phosphogypsum-based planted concrete.
[0048] Comparative Example 1 One type of bio-concrete differs from Example 1 in that sodium alginate is not added to the slow-release fertilizer granules.
[0049] The other raw materials and preparation methods are the same as in Example 1.
[0050] Comparative Example 2 One type of bio-concrete differs from Example 1 in that it does not contain slow-release fertilizer granules made from phosphogypsum, wood ash, sodium alginate, and water.
[0051] The other raw materials and preparation methods are the same as in Example 1.
[0052] Comparative Example 3 One type of bio-concrete differs from Example 1 in that it does not contain aggregates made from phosphogypsum, cement, mineral powder, and silica fume.
[0053] The other raw materials and preparation methods are the same as in Example 1.
[0054] Comparative Example 4 One type of bio-concrete differs from Example 1 in that it does not contain ammonium dihydrogen phosphate in its cementitious material.
[0055] The other raw materials and preparation methods are the same as in Example 1.
[0056] The vegetated concrete obtained in Examples 1 to 3 and Comparative Examples 1 to 3 was tested. The tests included: testing porosity using the water immersion method; testing compressive strength using the method specified in GB / T 50081-2019 (Cube Compressive Strength Test Method); testing fertilizer release rate at 14 days using the method specified in NY / T 2271-2012 (Determination of Nutrient Release Rate of Slow-Release Fertilizer); testing fertilizer release rate at 28 days using the method specified in NY / T 2271-2012 (Determination of Nutrient Release Rate of Slow-Release Fertilizer); and testing fertilizer release rate at 56 days using the method specified in NY / T 2271-2012 (Determination of Nutrient Release Rate of Slow-Release Fertilizer).
[0057] Plants were planted on the vegetated concrete obtained in Examples 1 to 3 and Comparative Examples 1 to 3 using the same planting method. The above-ground height of the plants was measured at 28 days and 56 days. The plant selected was Bermuda grass.
[0058] The obtained test results are shown in Table 1.
[0059] Table 1 Statistical Table of Performance Indicators of Vegetated Concrete
[0060] As can be seen from the comparison of Examples 1, 2, 3 and Comparative Example 1, the vegetated concrete without sodium alginate releases fertilizer in a short time and a large amount at a time under the wash of rainwater. The fertilizer released in a short time cannot be completely absorbed by the plants, which is not conducive to the long-term growth of the plants and causes a large amount of fertilizer to be wasted.
[0061] The comparison of Examples 1, 2, 3 and Comparative Example 2 shows that the growth effect of plants on the vegetated concrete without slow-release fertilizer is lower than that on the vegetated concrete with slow-release fertilizer.
[0062] As can be seen from the comparison of Examples 1, 2, 3 and Comparative Example 3, without the addition of phosphogypsum aggregate, there are almost no pores, which cannot provide growth space for plant roots, and the plants cannot grow.
[0063] The comparison of Examples 1, 2, 3 and Comparative Example 4 shows that without the addition of ammonium dihydrogen phosphate, the cementitious material has a high alkalinity, resulting in a high pH in the pores of the planted concrete, which leads to lower growth heights of bermudagrass at 28 days and 56 days.
[0064] The phosphogypsum-based vegetation concrete of the present invention uses industrial solid waste such as red mud and phosphogypsum as core raw materials. The raw material cost of its cementitious material can be reduced by more than 40% compared with the traditional solution that uses the same amount of ordinary Portland cement.
[0065] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A phosphogypsum-based planted concrete, characterized in that, By weight, it includes 110-170 parts of cementitious materials, 190-270 parts of aggregates, and 75-110 parts of slow-release fertilizer granules; The cementitious materials include 60-80 parts red mud, 20-40 parts mineral powder, 30-40 parts water, and 2-5 parts ammonium dihydrogen phosphate; the raw materials for the aggregates include 150-200 parts phosphogypsum, 10-20 parts cement, 10-20 parts mineral powder, and 20-25 parts silica fume; the raw materials for the slow-release fertilizer granules include 40-50 parts phosphogypsum, 20-30 parts wood ash, 10-15 parts sodium alginate, and 8-12 parts water.
2. The phosphogypsum-based planted concrete according to claim 1, characterized in that, The aggregate particle size is 15~30cm.
3. The phosphogypsum-based planted concrete according to claim 1, characterized in that, The particle size of slow-release fertilizer granules is 1~2mm.
4. The phosphogypsum-based planted concrete according to claim 1, characterized in that, The red mud is selected from one or more of the Bayer process red mud, sintering process red mud, and combined process red mud; Alternatively, the mineral powder may be selected from one or more of S75 mineral powder, S95 mineral powder, and S105 mineral powder.
5. The phosphogypsum-based planted concrete according to claim 1, characterized in that, The phosphogypsum is selected from one or more of dihydrate phosphogypsum, hemihydrate phosphogypsum, and anhydrous phosphogypsum. Alternatively, the cement may be ordinary Portland cement; Alternatively, the silica fume may be micro silica powder.
6. A method for preparing phosphogypsum-based planted concrete as described in any one of claims 1-5, characterized in that, Including the following steps: S1. After dry mixing the red mud and mineral powder in the raw materials of the cementitious material, add water and ammonium dihydrogen phosphate and stir to obtain the cementitious material; S2. The phosphogypsum, cement, mineral powder and silica fume in the raw materials of the aggregate are dry-mixed and then granulated to obtain the aggregate; S3. Mix and stir the phosphogypsum, wood ash and sodium alginate in the slow-release fertilizer granules. Spray water during the mixing process. Then granulate the moistened mixture and dry it to obtain slow-release fertilizer granules. S4. Mix and stir the cementitious materials, aggregates and slow-release fertilizer particles to obtain the phosphogypsum-based planted concrete.
7. The method for preparing phosphogypsum-based planted concrete according to claim 6, characterized in that, In S1, the dry mixing time is 1~2 minutes, and the stirring time is 2~3 minutes.
8. The method for preparing phosphogypsum-based planted concrete according to claim 6, characterized in that, In S2, the dry mixing time is 3-5 minutes; after granulation by a wet granulator, the mixture is cured for more than 1 day.
9. The method for preparing phosphogypsum-based vegetation concrete according to claim 6, characterized in that, In S3, the mixing time is 1~5 min; the drying method is: air drying at 50~60℃ for 30~50 min.
10. The method for preparing phosphogypsum-based planted concrete according to claim 6, characterized in that, In S4, the mixing time is 15~30s, and then the mixture is molded to obtain phosphogypsum-based planted concrete.