Full-solid-waste engineering soil prepared from a large amount of pressure-filtered alkaline residue and multiple solid wastes and a preparation method thereof

Abstract

The application discloses a kind of full solid waste engineering soil prepared by large amount of filter-pressing alkali residue and multiple solid wastes and a preparation method thereof, and relates to the technical field of filter-pressing alkali residue treatment.The application does not use soil resources, but uses filter-pressing alkali residue which is difficult to handle and utilize as reinforcing matrix and cementing material after mechanical crushing and grading according to particle size, realizes the graded resource utilization of filter-pressing alkali residue, reduces the consumption of soil resources and environmental pollution while achieving the designed strength, and reduces production cost;SO4 2− generated by the reaction of aluminate adjusts the early strength of full solid waste engineering soil, and the ettringite has the effect of reducing the early age drying shrinkage of full solid waste engineering soil and improving volume stability; cement is not used, and industrial solid wastes such as alkali residue, carbide slag and phosphogypsum having salt-alkali excitation effect are used to excite slag as cementing material, so that the goal of protecting the environment and reducing cost is achieved while treating solid waste.

Description

Technical Field

[0001] This invention relates to the field of filter press alkali residue treatment technology, and in particular to a whole solid waste engineering soil prepared by co-preparation of large amount of filter press alkali residue and multiple solid wastes, and its preparation method. Background Technology

[0002] Alkali residue is an alkaline waste residue generated during the ammonia-soda process for producing soda ash. It typically consists mainly of calcium salts such as CaCO3, CaSO4, and CaCl2. China discharges approximately 7.8 million tons of solid alkali residue annually. In chlor-alkali plants, alkali residue initially appears as a white slurry with high water retention, reaching over 90% moisture content. Previous studies utilizing alkali residue have often required drying and grinding processes, making resource utilization complex and costly, hindering widespread adoption, as illustrated by Chinese patents CN101182143A and CN108298942A.

[0003] Filtration is a relatively simple and economical waste liquid treatment technology commonly used by chlor-alkali enterprises to treat alkali slurry. After filtration, large quantities of alkali slurry are stored in stockpiles. Due to the large volume of emissions, high transportation costs, and limited resource utilization pathways, much of the filtration alkali slurry is disposed of through open-air stockpiling or even on-site burial, facing significant risks such as dam failure, soil degradation, and environmental pollution. Although the alkali slurry gains a certain strength after filtration, this strength is still insufficient for engineering requirements, and the compressed shape is limited, failing to meet the diverse application scenarios in the construction industry. Therefore, there is an urgent need to develop large-scale, high-value utilization technologies for filtration alkali slurry.

[0004] Engineering soil is a commonly used building material in civil engineering. It is made by mixing a certain proportion of cement as a solidifying agent into crushed soil, adding water, and mixing thoroughly. Through physical and chemical reactions between the components of the solidifying agent and with the soil, the physical and mechanical properties of the soil are significantly improved, forming a solidified body that meets strength requirements and is stable over a long period. It has advantages such as good homogeneity, good impermeability, and controllable quality, making it widely applicable. However, traditional engineering soil often uses excavated soil or even ordinary loess. If soil resources are not developed and utilized properly, the dynamic balance of material and energy transformation and exchange in the soil will be disrupted, leading to soil degradation and depletion, ultimately resulting in the deterioration of the ecosystem. Soil is an important component of the entire terrestrial ecosystem on Earth and a fundamental natural resource for human beings and other organisms. However, it is not inexhaustible. With the growth of the world's population, the rational development and utilization of soil resources has received widespread attention from all countries. Summary of the Invention

[0005] In response to the environmental pollution caused by the inability to dispose of filter press alkali residue in a timely manner, there is an urgent need to develop resource utilization technologies. This invention provides a method for preparing solid waste engineering soil by co-producing a large amount of filter press alkali residue with multiple solid wastes, and the preparation method thereof, which produces solid waste engineering soil with a 7-day strength of 0.5-1.5 MPa and a 28-day strength of 1.0-2.0 MPa.

[0006] In a first aspect, the present invention provides a solid waste engineering soil prepared by co-preparing a large amount of filter press alkali residue with multiple solid wastes, comprising component A, component B and water. Component A includes saturated surface dry filter press alkali residue, carbide slag slurry, phosphogypsum and slag, and component B is saturated surface dry filter press alkali residue.

[0007] Preferably, component A comprises, by dry weight, 15%–25% saturated surface dry-pressed alkali residue, 5%–10% carbide slag, 10%–15% phosphogypsum, and 50%–70% slag, and the total mass of the saturated surface dry-pressed alkali residue, carbide slag, phosphogypsum, and slag is 100%; and / or

[0008] Component B consists of two granular grades of saturated surface dry filter alkali residue: 0.15-4.75 mm granular saturated surface dry filter alkali residue and 4.75-19 mm granular filter alkali residue. The mass percentage of the 0.15-4.75 mm granular saturated surface dry filter alkali residue is 35% to 100%, and the mass percentage of the 4.75-19 mm granular saturated surface dry filter alkali residue is 0% to 65%. The total of the two particle size grades of saturated surface dry filter alkali residue is 100%.

[0009] Preferably, the saturated surface-dry filter press residue is the filter press residue freshly treated with filtration, which reaches a saturated surface-dry state after timely air drying. The moisture content of the saturated surface-dry filter press residue is 60%–70%. In the prior art, the dried filter press residue particles are loose and porous. Direct mixing during drying easily damages the filter press residue particles. After adding water and mixing, the dry and porous filter press residue particles compete for the mixing water, leading to the inability to carry out the hydration reaction, or even the failure to hydrate at all. The saturated surface-dry state of the filter press residue particles is filled with water in the pores, does not compete for the water used in the hydration reaction, and can even compensate for some of the water used in the hydration reaction. On the one hand, it achieves an internal curing effect, and on the other hand, it allows hydration products to be generated in the pores, thereby filling the pores and making the structure dense.

[0010] Preferably, the saturated surface-dry filter press residue of component A is obtained by mechanically crushing and timely air-drying the filter press residue to obtain granular saturated surface-dry filter press residue with a particle size of <0.15mm.

[0011] Preferably, the amount of component A is 25% to 35% of the mass of component B, and the water-to-binder ratio is 0.65 to 1.2.

[0012] Secondly, this invention provides a method for preparing all-solid-waste engineering soil by co-preparing filter press alkali residue with multiple solid wastes, comprising the following steps:

[0013] S1. Place the filter press alkali residue into a mechanical mixer and crush it by high-speed mixing. Then, screen the crushed filter press alkali residue particles to select three-stage particle sizes: <0.15mm, 0.15~4.75mm, and 4.75~19mm. After timely air drying, saturated surface-dried filter press alkali residue particles are obtained for later use.

[0014] S2. Based on the theory of closest packing, saturated surface dry-pressed filter alkali residue particles with particle size ranges of 0.15-4.75mm and 4.75-19mm were mixed evenly in different proportions, and their bulk density was measured. When the bulk density after mixing was the largest, the saturated surface dry-pressed filter alkali residue particles of the two particle size ranges reached close packing, and the optimal gradation of component B was obtained.

[0015] S3. Calculate the water content of saturated surface dry-pressed alkaline residue with a particle size <0.15mm and the water content of carbide slag slurry, and then calculate the required mass of saturated surface dry-pressed alkaline residue with a particle size <0.15mm and the mass of wet-based carbide slag and the water content of carbide slag slurry.

[0016] S4. Add saturated dry-pressed filter alkali residue (<0.15mm), carbide slag slurry, and phosphogypsum to a mixer and quickly mix them evenly to obtain a mixture as a co-activator. Add slag to the mixer and mix at low speed first, then add component B obtained in S2 and mix at high speed to obtain a fluidized solid waste engineering soil with fluidity.

[0017] Preferably, the composition and proportion of the saturated surface dry-pressed alkali residue particles in S2 of 0.15–4.75 mm are as follows: 0%–1% for 0.15 mm–0.3 mm saturated surface dry-pressed alkali residue particles, 5%–11% for 0.3 mm–0.6 mm saturated surface dry-pressed alkali residue particles, 16%–25% for 0.6 mm–1.18 mm saturated surface dry-pressed alkali residue particles, 19%–33% for 1.18 mm–2.36 mm saturated surface dry-pressed alkali residue particles, and 36%–56% for 2.36 mm–4.75 mm saturated surface dry-pressed alkali residue particles, with a total proportion of 100%.

[0018] The composition and proportion of 4.75-19mm saturated surface dry-pressed alkali residue particles are as follows: 4.75mm-9.5mm saturated surface dry-pressed alkali residue particles account for 22%-63%, 9.5mm-19mm saturated surface dry-pressed alkali residue particles account for 37%-78%, and the total proportion is 100%.

[0019] Preferably, in step S3, at least 9 samples of saturated dry-pressed alkali residue with a particle size <0.15mm are weighed, and the samples are dried separately. The moisture content of each sample of saturated dry-pressed alkali residue with a particle size <0.15mm is measured, and the average moisture content is used to represent the moisture content of the saturated dry-pressed alkali residue with a particle size <0.15mm.

[0020] Stir the carbide slag slurry evenly, take no less than 3 samples from the surface of the slurry, no less than 3 samples from the middle and no less than 3 samples from the bottom, and measure the water content of no less than 9 carbide slag slurry samples respectively. Use the average value to represent the water content of the carbide slag slurry.

[0021] Based on the dry basis mass percentage of component A, the solid content is obtained by measuring the water content of the saturated surface dry-pressed alkali residue and carbide slag slurry with small particles <0.15mm during use. Then, the required mass of saturated surface dry-pressed alkali residue and wet-based carbide slag with small particles <0.15mm is calculated from the dry basis mass in the mix proportion. At the same time, the water content in the carbide slag slurry is calculated.

[0022] Preferably, the rapid stirring time in S4 is 150±5s.

[0023] Preferably, the slag powder in S4 is added to the mixer, first stirred at low speed for 90 seconds, and at the beginning of the second 90 seconds, the B component obtained in S2 is added, then stirred at high speed for 300 seconds, and then the mixture on the blades and the pot wall is scraped into the middle of the pot, and then stirred at high speed for 120 seconds.

[0024] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0025] (1) This invention does not use soil resources. Instead, it mechanically crushes the difficult-to-process and utilize filter press alkali residue and classifies it according to particle size as component A (cementing material) and component B (reinforcing matrix). This allows the alkali residue content in the resulting engineering soil to reach more than 70%, resulting in a high utilization rate of filter press alkali residue. This achieves graded resource utilization of filter press alkali residue, reaches the design strength, reduces the consumption of soil resources and environmental pollution, and lowers production costs.

[0026] (2) Utilizing the SO4 content in phosphogypsum 2- The ettringite generated by the reaction with aluminates regulates the early strength of the solid waste engineering soil. At the same time, the formation of ettringite has a micro-expansion effect in the system. Under the optimal dosage, the expansion amount offsets the drying shrinkage of the solid waste engineering soil, thereby improving the volume stability of the solid waste engineering soil and thus increasing its durability. Instead of using cement, industrial solid wastes such as alkali slag, carbide slag, and phosphogypsum, which have salt-alkali activation effects, are used as cementing materials to co-activate the slag. This achieves the goals of environmental protection and cost reduction while treating solid waste.

[0027] (3) This invention innovatively crushes the filter press alkali residue that is difficult to process and utilize, and obtains filter press alkali residue particles with three particle sizes. The small particles of filter press alkali residue with a particle size of <0.15mm are used as cementing materials to form a salt-alkali synergistic activating effect with carbide slag and phosphogypsum. With the addition of active aluminosilicate material slag, the hydration reaction provides a guarantee for the formation of the strength of the solid waste engineering soil.

[0028] (4) This invention innovatively utilizes saturated surface dry filter press alkaline residue particles with particle size ranges of 0.15-4.75 mm and 4.75-19 mm in grade, and combines alkaline residue particles into reinforced matrices with different gradations. Based on the theory of closest packing of particles, the content of filter press alkaline residue particles in the two particle size ranges is adjusted to obtain a mixed reinforced matrices with the optimal gradation, which effectively reduces voids, correspondingly reduces the amount of water and cementitious materials per unit volume, and also makes the solid waste engineering soil have better mechanical properties, workability and durability.

[0029] (5) In this invention, the surface portion of the saturated surface-dry filter alkali residue particles can directly participate in the hydration reaction to generate strong C-(A)-SH gel and crystalline products such as ettringite and hydrated calcium aluminate. These hydration products form a structural network around the filter alkali residue particles, intertwined and solidified, and finally form strong solidified engineering soil.

[0030] (6) This invention prepares solid waste engineering soil with a 7-day strength of 0.5–1.5 MPa and a 28-day strength of 1.0–2.0 MPa (evaluated according to the strength standard of cement-stabilized soil based on JGJ / T 233-2011 "Specification for Cement-Soil Mix Design" and CJ / T 526-2018 "Soft Soil Stabilizer"). While meeting the functional requirements of engineering soil, this invention achieves resource utilization of other solid wastes such as filter press alkali residue, reducing environmental pollution and lowering production costs.

[0031] (7) This invention does not use cement. By comprehensively utilizing various solid wastes, the cost of solid waste disposal is greatly reduced, and the cost of engineering soil per unit strength is reduced by more than 30%, resulting in significant economic benefits. Attached Figure Description

[0032] Figure 1 SEM image of the dried alkaline residue from the filter press provided by this invention;

[0033] Figure 2 (a) is a cross-section of dry-pressed alkaline residue on saturated surface.

[0034] Figure 2 (b) is a cross-section of the dried filter press alkali residue. Detailed Implementation

[0035] To fully understand the purpose, features and effects of the present invention, the present invention will be described in detail through the following specific embodiments, but the present invention is not limited thereto.

[0036] The filter press residue used in the examples was freshly pressed residue from the filter press, which was then air-dried to a saturated surface-dry state. The moisture content of the saturated surface-dry filter press residue was 60%–70%, and its microstructure after drying was as follows: Figure 1 As shown, the dried alkaline filter press residue, after being saturated and surface-dried, has loose and porous particles. If it is directly mixed during drying, the alkaline filter press residue particles will be directly destroyed. After adding water and mixing, the porous alkaline filter press residue particles will compete for the mixing water, causing the hydration reaction to fail or even fail to hydrate.

[0037] This invention provides a method for preparing all-solid-waste engineering soil by co-processing multiple solid wastes with high-volume filter press alkali residue, comprising the following steps:

[0038] S1. Place the filter press alkali residue into a dry mechanical mixer and crush it by high-speed mixing for 15 minutes. Then, screen the crushed filter press alkali residue particles to obtain three-stage particle sizes: <0.15mm, 0.15-4.75mm, and 4.75-19mm. After timely air drying, saturated surface-dried filter press alkali residue particles are obtained for later use.

[0039] S2. Based on the theory of closest packing, saturated surface dry-pressed filter alkali residue particles with particle size ranges of 0.15-4.75mm and 4.75-19mm are mixed evenly in different proportions, and their bulk density is measured. When the bulk density after mixing is the largest, the saturated surface dry-pressed filter alkali residue particles of the two particle size ranges reach close packing, and the mixed reinforced matrix under the optimal gradation is obtained.

[0040] The particle size distribution and proportion of saturated surface dry pressure filter alkali residue particles of 0.15-4.75mm and 4.75-19mm are shown in Table 1 and Table 2, respectively.

[0041] Table 1. Percentage of particle mass in each particle size range of 0.15-4.75mm filter press alkali residue (total percentage is 100%)

[0042] Particle size range (mm) Percentage (%) >4.75 0～1 2.36～4.75 36～56 1.18～2.36 19～33 0.6～1.18 16～25 0.3～0.6 5～11 0.15～0.3 0～1 <0.15 0

[0043] Table 2. Percentage of particle mass in each particle size range of 4.75-19mm filter press alkali residue (total percentage 100%)

[0044] Particle size range (mm) Percentage (%) ＞19 0 9.5～19 37～78 4.75～9.5 22～63 <4.75 0

[0045] S3. Weigh at least 9 samples of saturated surface dry-pressed alkali residue with a particle size <0.15mm. Dry each sample separately and measure the moisture content of each sample. Use the average moisture content to represent the moisture content of the saturated surface dry-pressed alkali residue. Stir the carbide slag slurry in the storage tank evenly. Take at least 3 samples from the surface, 3 samples from the middle, and 3 samples from the bottom of the slurry. Measure the moisture content of at least 9 carbide slag slurry samples. Use the average value to represent the moisture content of the carbide slag slurry. According to the mix proportion, the solid content can be obtained from the moisture content of the saturated surface dry-pressed alkali residue and carbide slag slurry. Then, calculate the required mass of saturated surface dry-pressed alkali residue and wet-based carbide slag from the dry basis mass in the mix proportion. At the same time, calculate the moisture content in the carbide slag slurry.

[0046] S4. Add the required small-particle saturated dry-pressed alkali residue, carbide slag slurry, and phosphogypsum to the mixer and stir rapidly for 150 seconds. If the water content in the slurry does not meet the water-cement ratio requirements, supplement with tap water to obtain a homogeneous mixture as a co-activator. Then add slag powder to the mixer and stir at low speed (140±5 r / min rotation, 62±5 r / min revolution) for 90 seconds. At the beginning of the second 90 seconds, add component B and stir at high speed (285±10 r / min rotation, 125±10 r / min revolution) for 300 seconds. Then scrape the mixture on the blades and the pot wall into the middle of the pot and stir at high speed for another 120 seconds to obtain a fluidized solid waste engineering soil with fluidity.

[0047] Examples 1-10 were prepared according to the steps described above and the data in Table 1.

[0048] Comparative Example 1

[0049] The steps and dosages are the same as in Example 1, except that the saturated surface-dry filter alkali residue is replaced with a completely dry filter alkali residue.

[0050] The proportions of raw material components and dosages in Examples 1 to 10 are shown in Table 1.

[0051] Table 1. Components and Dosage Ratios

[0052]

[0053]

[0054] According to JGJ / T 233-2011 "Specification for Cement-Soil Mix Proportion Design" and CJ / T 526-2018 "Soft Soil Stabilizer", the engineering soils obtained in Examples 1 to 10 were evaluated using the strength standard of cement-stabilized soil, and the results are shown in Table 2.

[0055] Table 2 Detection results of Examples 1-10

[0056]

[0057]

[0058] The unconfined compressive strength results of the engineering soils obtained in Examples 1-3 show that there is an optimal ratio among saturated surface dry-pressed filter alkali residue particles with particle sizes ranging from 0.15 to 4.75 mm and 4.75 to 19 mm. Furthermore, the mixed reinforced matrix obtained by combining these optimal ratios can produce solid waste engineering soils with higher unconfined compressive strength. The unconfined compressive strength results of the products in Examples 1, 4, 5, and 8-10 show that the unconfined compressive strength of the solid waste engineering soil increases with increasing binder content and decreasing water-binder ratio. The unconfined compressive strength and drying shrinkage results of the products in Examples 6 and 7 show that the addition of phosphogypsum significantly improves the early-age unconfined compressive strength of the solid waste engineering soil and significantly reduces its drying shrinkage rate. The filter press residue used in Comparative Example 1, which was discharged from a soda ash plant, was obtained by crushing and drying the filter press residue until it was completely dry. Its 7-day and 28-day unconfined compressive strengths were both lower than those in Example 1. The 7-day unconfined compressive strengths of all listed samples exceeded 0.5 MPa, and their 28-day unconfined compressive strengths exceeded 1 MPa. These examples demonstrate that by adjusting the mix proportions of the reinforced matrix, the composition of the cementitious materials, the amount of cementitious materials added, and the water-cement ratio, engineering soils meeting various strength requirements can be prepared. The fluid, all-solid-waste engineering soil obtained immediately after mixing has good fluidity, is easy to transport, and is suitable for various projects and environments, possessing significant application value.

[0059] In China, the minimum unconfined compressive strength requirement for solidified soil is approximately 0.3 MPa. This requirement can be met by using a high-volume saturated surface dry filter press alkali residue in conjunction with other solid wastes to prepare all-solid-waste engineering soil. Therefore, this invention utilizes large-area stockpiles of filter press alkali residue and other industrial solid wastes to prepare all-solid-waste engineering soil that can completely replace traditional engineering soil in large quantities, turning waste into treasure, protecting the environment while reducing production costs, and possessing considerable industrial application prospects and economic benefits.

[0060] Finally, it should be noted that the above-listed embodiments are merely preferred embodiments of the present invention. Of course, those skilled in the art can make modifications and variations to the present invention. If such modifications and variations fall within the scope of the claims of the present invention and their equivalents, they should be considered as being within the protection scope of the present invention.

Claims

1. A type of solid waste engineering soil prepared by co-processing multiple solid wastes with high-volume filter press alkali residue, characterized in that, It includes component A, component B and water. Component A includes saturated surface dry filter alkali residue, carbide slag slurry, phosphogypsum and slag. Component B is saturated surface dry filter alkali residue. Component A contains 15%~25% saturated surface dry filter press alkali residue, 5%~10% calcium carbide slag, 10%~15% phosphogypsum, and 50%~70% slag by dry weight, and the total mass of saturated surface dry filter press alkali residue, calcium carbide slag, phosphogypsum, and slag is 100%. The saturated surface dry filter press alkali residue of component A is obtained by mechanically crushing filter press alkali residue and air-drying it in a timely manner to obtain granular saturated surface dry filter press alkali residue with a particle size of <0.15mm. Component B consists of two granular grades of saturated surface dry-pressed alkali residue: 0.15–4.75 mm and 4.75–19 mm. The mass percentage of the 0.15–4.75 mm granular saturated surface dry-pressed alkali residue is 35%–100%, and the mass percentage of the 4.75–19 mm granular saturated surface dry-pressed alkali residue is 0–65%. The total of the two particle sizes is 100%.

2. The all-solid-waste engineering soil prepared by co-processing multiple solid wastes with high-volume filter press alkali residue as described in claim 1, characterized in that, Saturated surface-dry filter press residue is the filter press residue that has just undergone filter press treatment and has reached a saturated surface-dry state after being air-dried in a timely manner. The moisture content of saturated surface-dry filter press residue is 60%~70%.

3. The all-solid-waste engineering soil prepared by co-processing multiple solid wastes with high-volume filter press alkali residue as described in claim 1, characterized in that, The amount of component A added is 25% to 35% of the mass of component B, and the water-cement ratio is 0.65 to 1.

2.

4. A method for preparing all-solid-waste engineering soil by co-preparation of high-volume filter press alkali residue and multiple solid wastes as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Place the filter press alkali residue into a mechanical mixer and crush it by high-speed mixing. Then, screen the crushed filter press alkali residue particles to select three-stage particle sizes of filter press alkali residue particles with particle sizes of <0.15mm, 0.15~4.75mm and 4.75~19mm respectively. After timely air drying, the saturated surface-dried filter press alkali residue particles are ready for use. S2. Based on the theory of closest packing, saturated surface dry-pressed filter alkali residue particles with particle size ranges of 0.15-4.75mm and 4.75~19mm were mixed evenly in different proportions, and their bulk density was measured respectively. When the bulk density after mixing is the largest, the saturated surface dry-pressed filter alkali residue particles in the two particle size ranges reach close packing. At this time, the optimal gradation of component B is obtained. S3. Calculate the water content of saturated surface dry-pressed alkaline residue with a particle size <0.15mm and the water content of carbide slag slurry, and then calculate the required mass of saturated surface dry-pressed alkaline residue with a particle size <0.15mm and the mass of wet-based carbide slag and the water content of carbide slag slurry. S4. Add saturated dry-pressed filter alkali residue (<0.15mm), carbide slag slurry, and phosphogypsum to a mixer and quickly mix them evenly to obtain a mixture as a co-activator. Add slag to the mixer and mix at low speed first, then add component B obtained in S2 and mix at high speed to obtain a fluidized solid waste engineering soil with fluidity.

5. The method for preparing all-solid-waste engineering soil by co-preparation of large-volume pressure filter alkali residue and multiple solid wastes according to claim 4, characterized in that, S2 The composition and proportion of saturated surface dry-pressed alkali residue particles with a diameter of 0.15~4.75mm are as follows: 0%~1% for 0.15mm~0.3mm saturated surface dry-pressed alkali residue particles, 5%~11% for 0.3mm~0.6mm saturated surface dry-pressed alkali residue particles, 16%~25% for 0.6mm~1.18mm saturated surface dry-pressed alkali residue particles, 19%~33% for 1.18mm~2.36mm saturated surface dry-pressed alkali residue particles, and 36%~56% for 2.36mm~4.75mm saturated surface dry-pressed alkali residue particles, with a total proportion of 100%. The composition and proportion of saturated surface dry-pressed alkali residue particles of 4.75~19mm are as follows: 4.75mm~9.5mm saturated surface dry-pressed alkali residue particles account for 22%~63%, 9.5mm~19mm saturated surface dry-pressed alkali residue particles account for 37%~78%, and the total proportion is 100%.

6. The method for preparing all-solid-waste engineering soil by co-preparation of large-volume pressure filter alkali residue and multiple solid wastes according to claim 4, characterized in that, S3. Weigh no less than 9 samples of small particle filter alkali residue with a particle size <0.15mm. Dry the saturated surface dry filter alkali residue samples with small particle size <0.15mm separately, and measure the moisture content of each sample of saturated surface dry filter alkali residue with small particle size <0.15mm. Use the average moisture content to represent the moisture content of the saturated surface dry filter alkali residue with small particle size <0.15mm. Stir the carbide slag slurry evenly, take no less than 3 samples from the surface of the slurry, no less than 3 samples from the middle and no less than 3 samples from the bottom, and measure the water content of no less than 9 carbide slag slurry samples respectively. Use the average value to represent the water content of the carbide slag slurry. Based on the dry weight percentage of component A, the solid content is obtained by measuring the water content of the saturated dry-pressed alkaline residue and carbide slag slurry with small particles <0.15mm. Then, the required mass of saturated dry-pressed alkaline residue and wet-based carbide slag with small particles <0.15mm is calculated from the dry weight in the mix proportion. At the same time, the water content in the carbide slag slurry is calculated.

7. The method for preparing all-solid-waste engineering soil by co-preparation of large-volume pressure filter alkali residue and multiple solid wastes according to claim 4, characterized in that, The rapid stirring time in S4 is 150±5s.

8. The method for preparing all-solid-waste engineering soil by co-preparation of large-volume pressure filter alkali residue and multiple solid wastes according to claim 4, characterized in that, S4 slag powder is added to the mixer. First, it is mixed at low speed for 90 seconds. At the beginning of the second 90 seconds, component B obtained from S2 is added. Then, it is mixed at high speed for 300 seconds. Then, the mixture on the blades and the pot wall is scraped into the middle of the pot. Then, it is mixed at high speed for 120 seconds.

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