Planting soil based on waste mud and preparation method thereof

Abstract

The invention provides planting soil based on waste mud and a preparation method of the planting soil, and belongs to the technical field of waste mud recycling. The planting soil based on the waste mud comprises the following raw materials: the waste mud, slag, magnesium oxide and desulfurized gypsum, wherein the water content of the waste mud is 100-120%; based on the dry mass of the waste slurry, the addition amount of the magnesium oxide is 5-10%. According to the planting soil based on the waste mud, the high-water-content waste mud is solidified through bulk solid waste such as the slag and the desulfurized gypsum, efficient utilization of the slag and the desulfurized gypsum is promoted, wheat is planted in the planting soil based on the waste mud, the germination rate is high, and plants grow healthily.

Description

Technical Field

[0001] The invention relates to the technical field of waste mud recycling, and in particular to a planting soil based on waste mud and a preparation method thereof. Background Art

[0002] In recent years, the construction of ports, waterway projects, and river and lake dredging projects has generated a large amount of waste mud with a high initial water content. The traditional method of treating waste mud is to simply dump it in a yard or landfill. In this process, a large area of ​​land resources is required and the treatment cycle is long. At the same time, the large amount of greenhouse gas emissions generated during the landfill process will have irreversible negative impacts on the surrounding ecosystem and human health.

[0003] At present, the treatment method for high-water content waste mud is mostly cement mixing and solidification to improve its engineering performance, so that these waste muds can be used as filling materials in port construction or land reclamation projects. However, since cement is not a green and low-carbon material, it is urgent to study a non-cement-based curing agent to replace cement curing agent to achieve green and low-carbon treatment of high-water content waste mud. Summary of the invention

[0004] The purpose of the present invention is to provide a planting soil based on waste mud and a preparation method thereof, so as to solve the problem that high-water content waste mud in the prior art cannot be treated in a green and low-carbon manner.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a planting soil based on waste mud, wherein the raw materials of the planting soil based on waste mud include: waste mud, slag, magnesium oxide, and desulfurized gypsum; the water content of the waste mud is 100-120%; and the addition amount of the magnesium oxide is 5-10% based on the dry mass of the waste mud.

[0007] Preferably, the amount of slag added is 10-15% based on the dry weight of the waste mud.

[0008] Preferably, the slag is S105 slag powder with a particle size of 500-800 mesh.

[0009] Preferably, the added amount of the desulfurized gypsum is 5-15% based on the dry mass of the waste mud.

[0010] Preferably, the particle size of the desulfurized gypsum is 250-400 meshes.

[0011] Preferably, the magnesium oxide is heavy magnesium oxide or light magnesium oxide, and has a particle size of 5 to 20 μm.

[0012] The present invention also provides a method for preparing the above-mentioned planting soil based on waste mud, comprising the following steps: adding slag, magnesium oxide, and desulfurized gypsum to the waste mud, and sequentially stirring and solidifying, curing, crushing, screening, and air-drying to obtain planting soil based on waste mud.

[0013] Preferably, the stirring and solidifying time is 15 to 25 minutes.

[0014] Preferably, the curing temperature is 20±2° C., the curing relative humidity is 95%, and the curing time is 28 days.

[0015] Preferably, the moisture content after air-drying is lower than 40%.

[0016] Beneficial effects of the present invention:

[0017] (1) The present invention utilizes bulk solid wastes such as slag and desulfurized gypsum to solidify waste mud with high water content, which can significantly reduce the water content of the waste mud in a short period of time, solve the problems of long-term storage of waste mud with high water content, large-scale occupation of land resources and environmental pollution, and realize green resource processing of waste mud.

[0018] (2) The present invention utilizes bulk solid wastes such as slag and desulfurized gypsum to solidify waste mud with high water content, thereby promoting the efficient utilization of slag and desulfurized gypsum. The obtained planting soil based on waste mud is used to plant wheat, and the germination rate is high, and the plants grow healthily.

[0019] (3) Compared with conventional cement curing agents, the present invention uses bidirectionally excited slag to solidify high-water content waste mud to prepare planting soil, which has obvious carbon reduction benefits and achieves the purpose of low-carbon resource treatment of high-water content waste mud, achieving the goal of "waste treatment, carbon reduction and carbon fixation". BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a flow chart of the process for preparing planting soil based on waste mud. DETAILED DESCRIPTION

[0021] The present invention provides a planting soil based on waste mud, wherein the raw materials of the planting soil based on waste mud include: waste mud, slag, magnesium oxide, and desulfurized gypsum; the water content of the waste mud is 100-120%; and the addition amount of the magnesium oxide is 5-10% based on the dry mass of the waste mud.

[0022] In the present invention, the added amount of the magnesium oxide is preferably 5 to 10%, more preferably 5%.

[0023] In the present invention, the addition amount of the slag is 10-15%, preferably 10% or 15%, based on the dry weight of the waste mud.

[0024] In the present invention, the slag is S105 slag powder with a particle size of 500-800 meshes.

[0025] In the present invention, based on the dry weight of the waste mud, the added amount of the desulfurized gypsum is 5-15%, preferably 10-15%, and more preferably 10%.

[0026] In the present invention, the particle size of the desulfurized gypsum is 250-400 meshes.

[0027] In the present invention, the magnesium oxide is heavy magnesium oxide or light magnesium oxide, preferably heavy magnesium oxide, and the particle size is 5 to 20 μm.

[0028] The present invention also provides a method for preparing the above-mentioned planting soil based on waste mud, comprising the following steps: adding slag, magnesium oxide, and desulfurized gypsum to the waste mud, and sequentially stirring and solidifying, curing, crushing, screening, and air-drying to obtain planting soil based on waste mud.

[0029] In the present invention, the waste mud is preferably sieved before adding slag, magnesium oxide and desulfurized gypsum, the purpose of which is to remove weeds, small stones and other debris in the waste mud.

[0030] In the present invention, the slag, magnesium oxide and desulfurized gypsum are preferably dried slag, magnesium oxide and desulfurized gypsum.

[0031] In the present invention, the stirring and solidifying time is 15 to 25 minutes, preferably 20 to 25 minutes.

[0032] In the present invention, the curing temperature is 20±2° C., the relative humidity is 95%, and the curing time is 28 days.

[0033] In the present invention, the moisture content after air drying is less than 40%.

[0034] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0035] The waste mud used in the embodiments of the present invention and the comparative examples is high-water content waste mud from Wuhe County, and its basic physical properties are as follows: specific gravity is 2.74, liquid limit is 58%, plastic limit is 25%, clay content (≤0.005mm) is 33.02%, silt content (0.005-0.075mm) is 42.24%, sand content (0.075-2mm) is 14.74%, and Wuhe County mud soil belongs to high liquid limit clay.

[0036] The high-water content waste mud from Wuhe County was prepared into waste mud with an initial water content of 116% to prepare planting soil.

[0037] Example 1

[0038] Dry the S105 slag powder, desulfurized gypsum and heavy magnesium oxide for later use;

[0039] The waste mud (initial moisture content is 116%) is sieved through a 2 mm sieve, and then dried S105 slag powder (particle size is 500-800 mesh), desulfurized gypsum (particle size is 250-400 mesh), and heavy magnesium oxide (particle size is 5-20 μm) are added. Based on the dry mass of the waste mud, the amount of S105 slag powder added is 15%, the amount of desulfurized gypsum added is 10%, and the amount of heavy magnesium oxide added is 5%. After stirring and curing for 20 minutes, the mixture is cured for 28 days at 20±2°C and a relative humidity of 95%. After curing, the mixture is crushed, sieved through a 2 mm sieve, and finally air-dried until the moisture content is less than 40% to obtain planting soil based on waste mud.

[0040] Example 2

[0041] The difference from Example 1 is that the addition amount of S105 slag powder is 10%, and other conditions are the same.

[0042] Example 3

[0043] The difference from Example 1 is that the addition amount of desulfurized gypsum is 5%, and other conditions are the same.

[0044] Example 4

[0045] The difference from Example 1 is that the addition amount of desulfurized gypsum is 15%, and other conditions are the same.

[0046] Example 5

[0047] The difference from Example 1 is that the addition amount of heavy magnesium oxide is 10%, and other conditions are the same.

[0048] Comparative Example 1

[0049] The difference from Example 1 is that the addition amount of heavy magnesium oxide is 15%, and other conditions are the same.

[0050] Comparative Example 2

[0051] The difference from Example 1 is that the addition amount of S105 slag powder is 20%, and other conditions are the same.

[0052] Wheat seeds were selected as test materials, and wheat seeds were planted in the planting soil of Examples 1 to 5 and Comparative Examples 1 to 2. Two replicate groups were set for each group. The germination rate and plant height of wheat were recorded after one month. The results are shown in Table 1:

[0053] Table 1 Germination rate and plant height test results of wheat planting

[0054]

[0055] By analyzing the data in Table 1, it can be seen from the comparison between Example 1, Example 5 and Comparative Example 1 that the greater the amount of heavy magnesium oxide added, the lower the germination rate of wheat, the germination rate of Example 1 is about twice that of Comparative Example 1, and the height of the plant does not change much; by comparing Example 1, Example 2 and Comparative Example 2, it can be seen that when the addition amount of S105 slag powder is 20%, the germination rate drops to 60%, and the plant height drops to 18±3 cm; by comparing Example 1, Example 3 and Example 4, it can be seen that as the addition amount of desulfurized gypsum increases, the germination of wheat first increases and then slightly decreases, and the plant height does not change much.

[0056] It can be seen from the above embodiments that the present invention provides a planting soil based on waste mud and a preparation method thereof. The raw materials of the planting soil based on waste mud include: waste mud, slag, magnesium oxide, and desulfurized gypsum, wherein the water content of the waste mud is 100-120%; the amount of magnesium oxide added is 5-10% based on the dry mass of the waste mud. The planting soil based on waste mud of the present invention uses bulk solid wastes such as slag and desulfurized gypsum to solidify the high-water content waste mud, thereby promoting the efficient utilization of slag and desulfurized gypsum, and planting wheat in the planting soil based on waste mud has a high germination rate and healthy plant growth.

[0057] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A planting soil based on waste mud, characterized in that: The raw materials of the planting soil based on waste mud include: waste mud, slag, magnesium oxide, and desulfurized gypsum; the water content of the waste mud is 100-120%; and the addition amount of the magnesium oxide is 5-10% based on the dry mass of the waste mud.

2. The planting soil based on waste mud according to claim 1, characterized in that: The added amount of the slag is 10-15% based on the dry weight of the waste mud.

3. The planting soil based on waste slurry according to claim 1 or 2, characterized in that: The slag is S105 slag powder with a particle size of 500-800 meshes.

4. The planting soil based on waste mud according to claim 3, characterized in that: The added amount of the desulfurized gypsum is 5-15% based on the dry weight of the waste mud.

5. The planting soil based on waste slurry according to claim 2 or 4, characterized in that: The particle size of the desulfurized gypsum is 250-400 meshes.

6. The planting soil based on waste slurry according to claim 5, characterized in that: The magnesium oxide is heavy magnesium oxide or light magnesium oxide, and the particle size is 5 to 20 μm.

7. The method for preparing planting soil based on waste mud according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: adding slag, magnesium oxide and desulfurized gypsum into waste mud, and sequentially stirring and solidifying, curing, crushing, screening and air-drying to obtain planting soil based on the waste mud.

8. The method for preparing planting soil based on waste mud according to claim 7, characterized in that: The stirring and curing time is 15 to 25 minutes.

9. The method for preparing planting soil based on waste mud according to claim 7 or 8, characterized in that: The curing temperature is 20±2° C., the relative humidity is 95%, and the curing time is 28 days.

10. The method for preparing planting soil based on waste mud according to claim 9, characterized in that: The moisture content after air drying is less than 40%.

Images