Efficient solidification and degradation method for river and lake sediment

Abstract

The application discloses a kind of high-efficiency solidification and digestion method of river and lake sediment, it is related to sludge treatment technical field, river and lake sediment and sulphoaluminate cement, silane modified montmorillonite, triisopropanolamine modified steel slag, quicklime are fully stirred and mixed, then the obtained mixture is backfilled to river and lake, open air natural curing 10-15 days, after river and lake is recharged with water.The application adds a certain amount of solidifying agent composed of sulphoaluminate cement, silane modified montmorillonite, triisopropanolamine modified steel slag and quicklime in river and lake sediment, and the treatment effect is good, not affected by the content of organic matter in river and lake sediment, and the obtained solidified sludge has high strength.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sludge treatment, in particular to a high-efficiency solidification and digestion method of river and lake sludge. BACKGROUND

[0002] In recent years, China has been continuously promoting river comprehensive management and governance projects, and a large amount of dredged sludge is generated in the process. The dredged sludge has a high water content and often contains heavy metals and organic pollutants. If not treated in time, it may produce odor and cause secondary pollution to the surrounding environment.

[0003] The main treatment methods of sludge are as follows: 1. Physical solidification method: by changing the physical properties of sludge, it becomes hard and cannot flow. Common physical solidification methods include compaction method, freezing method and drying method. Among them, the compaction method is to make the sludge hard by compaction treatment, which is suitable for the case of low water content of sludge. 2. Chemical solidification method: this method is to add solidification materials to the sludge, so that the solidification materials undergo hydration and hydrolysis reaction to generate hydrated gel products, so that the sludge has certain compressive strength and water stability. 3. Biological solidification method: using microorganisms to degrade organic matter in sludge into inorganic matter. It has the advantages of safety, environmental protection and can greatly reduce the treatment cost. It can combine aerobic and anaerobic bacteria to degrade sludge. 4. Incineration treatment: using high temperature oxidation to physically and chemically change the sludge in oxygen atmosphere to achieve the purpose of high-speed degradation of waste. However, this treatment method occupies a large space and requires a large amount of equipment. 5. Landfill treatment: burying sludge in a landfill site and placing it for about 15 years. The sludge decomposes and degrades under humidity and pressure, and the water evaporates, leaving the residue mineralized and decomposed into soil, which can be used for green and building structure flat land. Except for the chemical solidification method, the other methods not only have large engineering quantity, but also may cause secondary pollution to the environment. However, the current chemical solidification method does not cause secondary pollution to the environment, but the strength of the solidified material is not enough for secondary utilization, and the solidification effect is not good for sludge with high organic matter content. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a high-efficiency solidification and digestion method of river and lake sludge, which has good treatment effect and is not affected by the organic matter content in the river and lake sludge, and the solidified sludge has high strength.

[0005] To solve the above technical problems, the technical scheme of the present application is:

[0006] The application discloses a high-efficiency solidification and digestion method for river and lake sludge, which comprises the following steps: fully stirring and mixing river and lake sludge, sulphoaluminate cement, silane modified montmorillonite, triisopropanolamine modified steel slag and quicklime, backfilling the obtained mixture into the river and lake, and naturally curing for 10-15 days in the open air, and then re-storing water in the river and lake.

[0007] As the preferred technical scheme of the above technical scheme, the water content of the river and lake sludge is 80-85wt%, and the density is 1-2g / cm 3 .

[0008] As the preferred technical scheme of the above technical scheme, the sulphoaluminate cement is 42.5 sulphoaluminate cement, and the density is 3g / cm 3 .

[0009] As the preferred technical scheme of the above technical scheme, the stirring and mixing time is 2-3h.

[0010] As the preferred technical scheme of the above technical scheme, the amount of each component is as follows: the river and lake sludge is 110-130 parts by weight, the sulphoaluminate cement is 4-8 parts by weight, the silane modified montmorillonite is 0.5-1 part by weight, the triisopropanolamine modified steel slag is 5-12 parts by weight, and the quicklime is 2-5 parts by weight.

[0011] As the preferred technical scheme of the above technical scheme, the preparation method of the silane modified montmorillonite is as follows: adding acetic acid into an ethanol solution to adjust the pH value of the solution to 3-4, then adding an aminopropyl triethoxysilane, and then adding acidified nano-montmorillonite, grinding and treating, and finally washing the precipitate with ethanol to obtain the silane modified montmorillonite.

[0012] As the preferred technical scheme of the above technical scheme, the average particle size of the nano-montmorillonite is 20-30nm, the concentration of the ethanol solution is 95wt%, the mass ratio of the aminopropyl triethoxysilane to the acidified nano-montmorillonite is 1: (30-50), the grinding and treating temperature is 75-85 DEG C, and the grinding and treating time is 30-60min.

[0013] As the preferred technical scheme of the above technical scheme, the acidified nano-montmorillonite is prepared by the following steps: placing nano-montmorillonite in dilute sulfuric acid with a concentration of 20-30wt% for normal temperature treatment, keeping the solid-liquid mass ratio to be 1:20 during the treatment, and treating for 10-20min.

[0014] As the preferred technical scheme of the above technical scheme, the preparation method of the triisopropanolamine modified steel slag is as follows: crushing the steel slag through a 20-mesh sieve, and then mixing and ball-milling the steel slag with triisopropanolamine to obtain the triisopropanolamine modified steel slag.

[0015] Preferably, the mass ratio of the steel slag and the triisopropanolamine is 1: (0.05-0.1); and the rotating speed during the ball milling is 200-300 r / min, and the time is 30-50 min.

[0016] By adopting the above technical scheme, the application has the following beneficial effects:

[0017] The application adds a certain amount of sulphoaluminate cement, silane modified montmorillonite, triisopropanolamine modified steel slag and quicklime into the river and lake sediment as a mixed solidifying agent. The sulphoaluminate cement has high early strength and can produce certain hydration products, such as tricalcium silicate and tricalcium aluminate, which can react with water, clay minerals and the like in the sediment to generate hydraulic substances such as hydrated calcium silicate and hydrated calcium aluminate, so that the sediment becomes more solid. At the same time, the porosity of the sediment is reduced, and the strength and stability of the solidified sediment are improved. The silane modified montmorillonite has good dispersibility and good swelling capacity and water absorption characteristics, which can effectively fill the cracks and pores generated in the cement hydration process, thereby improving the strength of the solidified sediment. Moreover, the organic silane on the surface of the nano montmorillonite can also react with the clay minerals in the sediment to generate more stable silicates, further enhancing the solidity of the sediment. The triisopropanolamine can effectively activate the steel slag to generate substances with adhesion, replacing part of the cement as cementitious materials, which not only reduces the cost, but also makes the sediment more solid. At the same time, the triisopropanolamine can also improve the porosity and permeability of the sediment and improve its waterproof performance. The quicklime reacts with water and carbon dioxide in the sediment to generate substances such as calcium hydroxide, making the sediment more solid. At the same time, the quicklime can also increase the alkalinity of the sediment and reduce the activity of heavy metal ions therein, thereby reducing the harm to the environment. DETAILED DESCRIPTION

[0018] The application will be further described in conjunction with the following examples. It should be understood that these examples are only used to illustrate the application and not to limit the scope of the application. EXAMPLE

[0019] S1: The nano montmorillonite is placed in a concentrated sulfuric acid with a concentration of 20wt% for normal temperature treatment for 20 min to prepare acidified montmorillonite, and the solid-liquid mass ratio is kept at 1:20 during the treatment;

[0020] S2: 0.1g of aminopropyl triethoxysilane is added to 50ml of 95wt% ethanol solution, and then 5g of acidified nano montmorillonite is added. Then, the mixture is ground at 80℃ for 30 min, and finally the precipitate is washed with ethanol to prepare silane modified montmorillonite;

[0021] S3: 10 g of steel slag was crushed through a 20 mesh sieve, then mixed with 0.6 g of triisopropanolamine, and ball-milled at a speed of 200 r / min for 30 min to prepare triisopropanolamine modified steel slag;

[0022] S4: 120 parts of river and lake sediment with a water content of 85 wt%, an organic matter content of 3.5 wt%, 5 parts of sulphoaluminate cement, 0.5 parts of silane modified montmorillonite, 7 parts of triisopropanolamine modified steel slag, and 2 parts of quicklime were fully stirred and mixed for 2 h, then the obtained mixture was backfilled into the river and lake, and naturally cured in the open air for 14 days, and then the river and lake were recharged with water. Example

[0023] S1: nano-montmorillonite was placed in dilute sulfuric acid with a concentration of 20 wt% for normal temperature treatment for 20 min to prepare acidified montmorillonite, and the solid-liquid mass ratio was maintained at 1:20 during the treatment;

[0024] S2: 0.1 g of aminopropyl triethoxysilane was added to a 95 wt% ethanol solution of 50 ml, then 5 g of acidified nano-montmorillonite was added, and then the mixture was ground at 80°C for 30 min, and finally the precipitate was washed with ethanol to prepare silane modified montmorillonite;

[0025] S3: 10 g of steel slag was crushed through a 20 mesh sieve, then mixed with 0.6 g of triisopropanolamine, and ball-milled at a speed of 300 r / min for 30 min to prepare triisopropanolamine modified steel slag;

[0026] S4: 120 parts of river and lake sediment with a water content of 85 wt%, an organic matter content of 3.5 wt%, 5 parts of sulphoaluminate cement, 0.6 parts of silane modified montmorillonite, 7 parts of triisopropanolamine modified steel slag, and 3 parts of quicklime were fully stirred and mixed for 2 h, then the obtained mixture was backfilled into the river and lake, and naturally cured in the open air for 14 days, and then the river and lake were recharged with water. Example

[0027] S1: nano-montmorillonite was placed in dilute sulfuric acid with a concentration of 20 wt% for normal temperature treatment for 20 min to prepare acidified montmorillonite, and the solid-liquid mass ratio was maintained at 1:20 during the treatment;

[0028] S2: 0.1 g of aminopropyl triethoxysilane was added to a 95 wt% ethanol solution of 50 ml, then 5 g of acidified nano-montmorillonite was added, and then the mixture was ground at 80°C for 30 min, and finally the precipitate was washed with ethanol to prepare silane modified montmorillonite;

[0029] S3: 10 g of steel slag was crushed through a 20 mesh sieve, then mixed with 0.6 g of triisopropanolamine, and ball-milled at a speed of 300 r / min for 50 min to prepare triisopropanolamine modified steel slag;

[0030] S4: 120 parts of river and lake sediment with a water content of 85 wt%, an organic matter content of 3.5 wt%, 8 parts of sulphoaluminate cement, 0.7 parts of silane modified montmorillonite, 8 parts of triisopropanolamine modified steel slag, and 2 parts of quicklime were fully stirred and mixed for 2 h, then the obtained mixture was backfilled into the river and lake, and naturally cured in the open air for 14 days, and then the river and lake were recharged with water. Example

[0031] S1: nano-montmorillonite was treated in 20 wt% dilute sulfuric acid at room temperature for 20 min to prepare acidified montmorillonite, and the solid-liquid mass ratio was kept at 1:20 during the treatment;

[0032] S2: 0.1 g of aminopropyl triethoxysilane was added to 50 ml of 95 wt% ethanol solution, then 5 g of acidified nano-montmorillonite was added, and then the mixture was ground at 80°C for 30 min, and finally the precipitate was washed with ethanol to prepare silane modified montmorillonite;

[0033] S3: 10 g of steel slag was crushed through a 20 mesh sieve, then mixed with 0.6 g of triisopropanolamine, and ball-milled at a speed of 280 r / min for 30 min to prepare triisopropanolamine modified steel slag;

[0034] S4: 120 parts of river and lake sediment with a water content of 85 wt%, an organic matter content of 3.5 wt%, 5 parts of sulphoaluminate cement, 0.6 parts of silane modified montmorillonite, 7 parts of triisopropanolamine modified steel slag, and 3 parts of quicklime were fully stirred and mixed for 2 h, then the obtained mixture was backfilled into the river and lake, and naturally cured in the open air for 10-15 days, and then the river and lake were recharged with water. Example

[0035] S1: nano-montmorillonite was treated in 20 wt% dilute sulfuric acid at room temperature for 20 min to prepare acidified montmorillonite, and the solid-liquid mass ratio was kept at 1:20 during the treatment;

[0036] S2: 0.1 g of aminopropyl triethoxysilane was added to 50 ml of 95 wt% ethanol solution, then 5 g of acidified nano-montmorillonite was added, and then the mixture was ground at 80°C for 30 min, and finally the precipitate was washed with ethanol to prepare silane modified montmorillonite;

[0037] S3: 10 g of steel slag was crushed through a 20 mesh sieve, then mixed with 0.6 g of triisopropanolamine, and ball-milled at a rotation speed of 300 r / min for 50 min to prepare triisopropanolamine modified steel slag;

[0038] S4: 120 parts of river and lake sediment with a water content of 85 wt%, an organic matter content of 3.5 wt%, 7 parts of sulphoaluminate cement, 0.7 parts of silane modified montmorillonite, 11 parts of triisopropanolamine modified steel slag, and 4 parts of quicklime were fully stirred and mixed for 3 h, then the obtained mixture was backfilled into the river and lake, and naturally cured in the open air for 14 days, and then the river and lake was refilled with water.

[0039] Comparative Example 1

[0040] Compared with Example 5, the steel slag added in the treatment process of the river and lake sediment of Comparative Example 1 was not modified, and other conditions were the same as those of Example 5.

[0041] Comparative Example 2

[0042] Compared with Example 5, the river and lake sediment of Comparative Example 2 was not added with triisopropanolamine modified steel slag in the treatment process, and other conditions were the same as those of Example 5.

[0043] Comparative Example 3

[0044] Compared with Example 5, the nano-montmorillonite used in the treatment process of the river and lake sediment of Comparative Example 3 was not modified by aminopropyl triethoxysilane, and other conditions were the same as those of Example 5.

[0045] Comparative Example 4

[0046] Compared with Example 5, the river and lake sediment of Comparative Example 4 was not added with silane modified montmorillonite in the treatment process, and other conditions were the same as those of Example 5.

[0047] Comparative Example 5

[0048] Compared with Example 5, the river and lake sediment of Comparative Example 5 was not added with triisopropanolamine modified steel slag and silane modified montmorillonite in the treatment process, and other conditions were the same as those of Example 5.

[0049] The unconfined compressive strength of the solidified sediment prepared in the above examples and comparative examples was tested before the water was stored, and the test results are shown in Table 1.

[0050] Table 1

[0051]

[0052] As can be seen from the above test results, the river and lake sediment is better solidified by adding a certain amount of silane modified montmorillonite and triisopropanolamine modified steel slag, and the strength of the solidified sediment is obviously improved.

[0053] It is to be understood that while the application has been described in conjunction with the preferred specific embodiments thereof, that the same are intended to illustrate and not to limit the application. Many other changes, modifications, as well as numerous explicitly and implicitly inherent variations thereof, can be made in the above described application without departing from the scope of the application as set forth in the claims below.

Claims

1. A highly efficient method for solidifying and digesting river and lake sediment, characterized in that: By weight, 110-130 parts of river and lake bottom sediment, 4-8 parts of sulfoaluminate cement, 0.5-1 parts of silane-modified montmorillonite, 5-12 parts of triisopropanolamine-modified steel slag, and 2-5 parts of quicklime are thoroughly mixed. The resulting mixture is then backfilled into the river or lake and left to cure naturally in the open air for 10-15 days. After that, water is added back into the river or lake. The preparation method of the silane-modified montmorillonite is as follows: acetic acid is added to an ethanol solution to adjust the pH of the solution to 3-4, then aminopropyltriethoxysilane is added, followed by acidified nano-montmorillonite, grinding treatment, and finally washing the precipitate with ethanol to obtain silane-modified montmorillonite. The preparation method of the triisopropanolamine-modified steel slag is as follows: the steel slag is crushed and passed through a 20-mesh sieve, and then mixed with triisopropanolamine and ball-milled to obtain triisopropanolamine-modified steel slag. Organosilane-modified montmorillonite has expansion capacity and water absorption properties, filling cracks and pores generated during cement hydration, thereby improving the strength of solidified sediment. The organosilanes on the surface of nano-montmorillonite react with clay minerals in the sediment to generate more stable silicates, further enhancing the solidity of the sediment.

2. The efficient solidification and digestion method for river and lake bottom sediments according to claim 1, characterized in that: The water content of the river and lake bottom sediment is 80-85 wt%, and the density is 1-2 g / cm³. 3 .

3. The efficient solidification and digestion method for river and lake bottom sediments according to claim 1, characterized in that: The sulfoaluminate cement is 42.5 sulfoaluminate cement with a density of 3 g / cm³. 3 .

4. The efficient solidification and digestion method for river and lake bottom sediments according to claim 1, characterized in that: The time for thorough mixing is 2-3 hours.

5. The efficient solidification and digestion method for river and lake bottom sediments according to claim 1, characterized in that: The average particle size of the nano-montmorillonite is 20-30 nm, the concentration of the ethanol solution is 95 wt%, and the mass ratio of the aminopropyltriethoxysilane to the acidified nano-montmorillonite is 1:(30-50); the grinding treatment temperature is 75-85℃ and the time is 30-60 min.

6. The efficient solidification and digestion method for river and lake bottom sediments according to claim 1, characterized in that: The acidified nano-montmorillonite is prepared by placing the nano-montmorillonite in dilute sulfuric acid with a concentration of 20-30wt% at room temperature, maintaining a solid-liquid mass ratio of 1:20, and treating for 10-20 minutes.

7. The efficient solidification and digestion method for river and lake bottom sediments according to claim 1, characterized in that: The mass ratio of steel slag to triisopropanolamine is 1:(0.05-0.1); the ball milling speed is 200-300 r / min, and the time is 30-50 min.

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