Method for modifying waste mucky clay into a planting soil and a planting soil

Abstract

The application relates to a method for modifying abandoned argillaceous clay into planting soil, which comprises the following steps: adding a modifier into the abandoned argillaceous clay, wherein the modifier comprises modified particles and potassium fulvate of mineral origin, and the modified particles are ceramsite fired by the abandoned argillaceous clay itself; and mixing the abandoned argillaceous clay and the modifier to obtain green planting soil. The application also provides the green planting soil prepared by the method. Compared with directly treating the abandoned argillaceous clay as abandoned earthwork, the method can change waste into treasure, modify the abandoned argillaceous clay into green planting soil, and is used for plant planting.

Description

Technical Field

[0001] This application relates to the field of waste soil remediation technology, and in particular to a method for modifying waste silty clay into planting soil and the planting soil itself. Background Technology

[0002] Engineering projects such as foundation excavation and river dredging generate a lot of waste soil, especially some abandoned silty clay soil. Due to its high water content, high viscosity, high organic matter content, and poor particle size distribution, this waste silty clay soil is difficult to use directly and is mostly treated as waste soil, occupying a large amount of waste soil sites and causing continuous pollution to the environment.

[0003] Therefore, how to process waste silty clay for recycling has become an urgent problem for those skilled in the art. Summary of the Invention

[0004] In order to process waste silty clay for waste utilization, this application provides a method for modifying waste silty clay into planting soil and the planting soil.

[0005] To achieve the objective of this invention, a method for modifying waste silty clay into planting soil is provided, comprising the following steps:

[0006] Some of the discarded silty clay was collected and fired into ceramsite.

[0007] Add a modifier to the remaining waste silty clay, the modifier comprising modified particles and mineral-derived potassium humate, the modified particles being ceramsite obtained by firing.

[0008] Waste silty clay and soil conditioner are mixed to obtain greening planting soil.

[0009] According to another aspect of this application, a planting soil is provided, which is prepared by the aforementioned method of modifying waste silty clay into planting soil.

[0010] Compared to directly disposing of waste silty clay as waste soil, which occupies a large amount of spoil disposal sites and continuously pollutes the environment, this application can turn waste into treasure by improving waste silty clay into planting soil for planting green plants. The organic matter in the waste silty clay provides nutrients for plants, while the expanded clay granules produced from the clay itself improve soil structure, making the soil more aerated and permeable. Furthermore, potassium humate from mineral sources loosens the soil's granular structure, improving its water and fertilizer retention capacity and promoting plant growth. Attached Figure Description

[0011] Figure 1This document illustrates a process flow diagram of a method for modifying waste silty clay into planting soil according to an embodiment of this application. Detailed Implementation

[0012] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0013] It should be understood that the terms "length", "width", "height", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application or simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0014] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, components, and circuits well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0015] This application provides a method for modifying waste silty clay into green planting soil, including the following steps: S100, dividing the waste silty clay to be modified into two parts, collecting one part for firing, and firing the waste silty clay into ceramsite.

[0016] S300, add an amendment to another portion of the waste silty clay, the amendment including modified particles and mineral-derived potassium humate, the modified particles being ceramsite made from the aforementioned waste silty clay itself; S400, mix the waste silty clay and the amendment to obtain greening planting soil.

[0017] Waste silty clay generally has a high organic matter content, making it unsuitable for direct use in engineering projects. The organic matter content requirement for engineering soil is generally no more than 5%. This application utilizes the high organic matter content of waste silty clay to modify it into planting soil for landscaping. By utilizing the organic matter, waste can be turned into a valuable resource. Furthermore, in areas with abundant waste soil, planting soil for landscaping is generally scarce, resulting in substantial economic and social benefits.

[0018] The main factors preventing waste silty clay from being directly used as planting soil include excessive density, low non-capillary porosity, and low soil infiltration rate, resulting in poor aeration, water retention, and low germination rate. By improving or eliminating these limiting factors using appropriate methods, and by adding organic or inorganic fertilizers to adjust soil texture, waste silty clay can be modified into high-quality planting soil. To achieve this, porous and lightweight materials such as sawdust, vermiculite, and diatomaceous earth are typically added to the waste silty clay for modification. However, these materials require additional procurement and transportation, and their availability and cost are not ideal.

[0019] This application innovatively utilizes waste silty clay to produce porous, lightweight expanded clay aggregates, which are then added to the waste silty clay for modification. This process reduces soil density, increases soil particle size, and loosens the soil structure, creating non-capillary pores (also known as macropores). The increased number of macropores enhances non-capillary porosity (the percentage of soil volume occupied by macropores), thus altering the soil's structure. Macropores, also called soil aeration pores, allow for soil aeration and water permeability, promoting crop growth. Preferably, the non-capillary porosity of the planting soil is adjusted to 50-60% or more of the total porosity by adjusting the expanded clay aggregate properties, quantity, and mixing ratio with the waste silty clay.

[0020] Potassium humate from mineral sources can effectively loosen the soil aggregate structure of abandoned silty clay, improve the soil's water and fertilizer retention capacity, regulate pH value, reduce the content of heavy metals in the soil, and reduce the harm of salt ions to seeds and seedlings. While providing nitrogen, phosphorus, potassium, organic matter and other nutrients, it has significant effects on nitrogen fixation, phosphorus solubilization, and potassium activation, thus promoting root growth and seedling development. It can also enhance the adhesion and rapid absorption capacity of plant roots, and has a significant effect on physiological diseases caused by micronutrient deficiency in plants.

[0021] Compared to directly disposing of waste silty clay as waste soil, which occupies a large amount of spoil disposal sites and continuously pollutes the environment, this application can turn waste into treasure by improving waste silty clay into planting soil for planting green plants. The organic matter in the waste silty clay provides nutrients for crops, while expanded clay pebbles improve soil structure, making the soil more aerated and permeable. Furthermore, potassium humate from mineral sources loosens the soil's granular structure, improving its water and fertilizer retention capacity and promoting plant growth.

[0022] In one possible implementation, after mixing the amendment and waste silty clay in S300, the process also includes a soil fertility adjustment step in S500. Specifically, the soil fertility adjustment in S500 includes the following steps: based on the planting fertility test results of the mixed soil of amendment and waste silty clay, organic fertilizer, compound fertilizer, or single-element fertilizer is added to the mixed soil of amendment and waste silty clay to specifically adjust the fertility. Once the standard for greening planting soil is met, qualified greening planting soil is obtained.

[0023] It should be noted that this application does not impose specific limitations on the fertility testing methods or the standards for soil parameters after fertility adjustment, as long as they meet the planting requirements and the growth requirements of plants. The methods can be flexibly selected based on actual usage needs, or the fertility of the improved greening planting soil can be tested and adjusted according to the technical requirements of fertility in CJ / T340-2016 "Greening and Greening Planting Soil" or the fertility requirements of the application scenario.

[0024] In one possible implementation, before adding the modifier to the waste silty clay in step S300, step S100 further includes a step of preparing ceramsite. Preparing the ceramsite includes the following steps: collecting a portion of the waste silty clay to be modified, and firing the collected waste silty clay into ceramsite. In other words, first, a portion of the waste silty clay to be modified is collected, the collected waste silty clay is fired into ceramsite, then a modifier is prepared, and the modifier is added to the original waste silty clay to be modified in a certain proportion, and mixed evenly.

[0025] This method utilizes locally sourced materials and treats waste with waste, turning discarded silty clay into one of the raw materials for amendments. This can expand the amount of solid waste that can be disposed of, effectively reduce the amount of solid waste, reduce the procurement and transportation of external materials, and significantly reduce costs. At the same time, the expanded clay can be sold as a commodity, increasing the added value of recycled products.

[0026] It should be noted that this application does not specifically limit the firing process and parameters of the expanded clay aggregate. As long as the waste silty clay can be fired to achieve the characteristics of water absorption, air permeability, and lightweight, and the addition of waste silty clay can effectively reduce soil viscosity and improve its non-capillary porosity, infiltration rate, water retention, and plant germination rate, it is acceptable. Furthermore, since the modified soil is for landscaping, the hardness of the fired expanded clay aggregate does not need to be too high; a porous and loose structure is preferable, which will significantly reduce firing costs. Preferably, the firing temperature is below 900℃, and the bulk density of the expanded clay aggregate is 310–500 kg / m³. 3 The cylinder compressive strength is 5-30 MPa, and the softening coefficient is greater than or equal to 0.8.

[0027] In one possible implementation, the bulk density of the ceramsite is 310–500 kg / m³.3 The compressive strength of the ceramsite is 5-30 MPa, and the softening coefficient of the ceramsite is greater than or equal to 0.8.

[0028] In one possible implementation, before adding the modifier to the waste silty clay in S300, the step of preparing the modifier is further included in S200, specifically: adding 1% to 5% (by mass fraction of the ceramsite) of mineral-derived potassium humate to the ceramsite, and mixing the ceramsite and the mineral-derived potassium humate to obtain the modifier.

[0029] In one possible implementation, the particle size of the ceramsite is 0–20 mm. Further, according to particle size, the modified particles contain 60%–70% ceramsite with a particle size of 0–5 mm, preferably 65% ​​by mass; 20%–30% ceramsite with a particle size of 5–10 mm, preferably 25% by mass; and 0–10% ceramsite with a particle size of 10–20 mm, preferably 10% by mass.

[0030] In one possible implementation, when the modifier is added to the waste silty clay in S300, the weight ratio of the modifier to the waste silty clay is 1:1 to 3, preferably 1:1, 1:1.5, 1:2, or 1:3.

[0031] In addition, this application provides two embodiments as follows, which test the performance of the modified greening planting soil.

[0032] Example 1:

[0033] 1000 kg of waste silty clay was fired into ceramsite as modified particles at a firing temperature of 800℃. The bulk density of the ceramsite was 350 kg / m³. 3 The compressive strength of the cylinder is 7.5 MPa, and the softening coefficient is 0.8. In the modified particles, the mass fraction of ceramsite with a particle size of 0–5 mm is 60%; the mass fraction of ceramsite with a particle size of 5–10 mm is 30%; and the mass fraction of ceramsite with a particle size of 10–20 mm is 10%.

[0034] To prepare the modifier, take 1000 kg of modified particles and add 30 kg of mineral-derived potassium humate to obtain the modifier;

[0035] The soil for landscaping is prepared by mixing the soil conditioner and waste silty clay in a weight ratio of 1:3.

[0036] The performance of the modified planting soil was tested, and the results are shown in Table 1 below:

[0037]

[0038] Example 2:

[0039] Preparation of planting soil for greening: Except for the conditioner and waste silty clay being mixed in a 1:1 weight ratio, the rest is consistent with Example 1.

[0040] The performance of the modified planting soil was tested, and the results are shown in Table 2 below:

[0041]

[0042] In one possible implementation, the mixing step of the amendment and waste silty clay is carried out using a forced mixer or planetary mixer to ensure uniform mixing. The flexible selection and setting of the mixing ratio and mixing time are based on two points: first, the mixing should be sufficient to loosen the waste silty clay; second, the density of the mixed soil should be less than 1.35 mg / m³. 3 When the non-capillary porosity is 5% to 25% and the soil infiltration rate is greater than or equal to 5 mm / h, the ratio is appropriate. Otherwise, continue to adjust the ratio and continue to stir and mix until the standard is met, thus obtaining the basic improved greening planting soil.

[0043] According to another aspect of this application, a greening planting soil is provided, which can be used as greening planting soil and is prepared by the aforementioned method of modifying waste silty clay into greening planting soil.

[0044] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for modifying waste silty clay into planting soil, characterized in that, Includes the following steps: A portion of the waste silty clay is collected and fired into ceramsite; wherein the bulk density of the ceramsite is 310~500kg / m³; the compressive strength of the ceramsite is 5~30MPa; and the softening coefficient of the ceramsite is greater than or equal to 0.

8. Add a modifier to the remaining waste silty clay, the modifier comprising modified particles and mineral-derived potassium humate, the modified particles being ceramsite obtained by firing; Waste silty clay and soil conditioner are mixed to obtain greening planting soil; The process includes a step of preparing the modifier after firing the ceramsite and before adding the modifier to the waste silty clay. Specifically, 1% to 5% of mineral-derived potassium humate is added to the ceramsite obtained from firing the waste silty clay, and the ceramsite and the mineral-derived potassium humate are mixed to obtain the modifier.

2. The method for modifying waste silty clay into planting soil according to claim 1, characterized in that, The particle size of the ceramsite is 0~20mm.

3. The method for modifying waste silty clay into planting soil according to claim 2, characterized in that, According to particle size, the modified particles have the following mass fractions: 60% to 70% for 0 to 5 mm, 20% to 30% for 5 to 10 mm, and 0 to 10% for 10 to 20 mm.

4. The method for modifying waste silty clay into planting soil according to claim 1, characterized in that, When the modifier is added to the waste silty clay, the weight ratio of the modifier to the waste silty clay is 1:1 to 3.

5. A type of planting soil, characterized in that, The planting soil is prepared by the method described in any one of claims 1-4 for modifying waste silty clay into planting soil.

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