A mud treating agent, its preparation method and application

Abstract

The application discloses a mud treatment agent and a preparation method and application thereof. The mud treatment agent comprises, in terms of weight fractions, 100 parts of a silt coagulating agent, 20-40 parts of a consolidating agent and 5-15 parts of a heavy metal ion removing agent. The silt coagulating agent is a mixture of sodium polyacrylate, alginate and iron salt at a mass ratio of 10:1-4:0.5-2. The heavy metal ion removing agent is prepared by grafting reaction of carboxymethyl chitosan and cysteine. The mud treatment agent can promote the aggregation of solids in the mud, which is conducive to the separation of the mud and water, reduces the water content of the dewatered cake obtained by the separation of the mud and water, and realizes the solidification and reduction of the mud.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of environmental protection, and more particularly to a mud treatment agent and a preparation method and application thereof. BACKGROUND

[0002] With the pace of development of electric power accelerating, the power grid has been rapidly developed, and the construction of the substation as a power grid node project and an important support is particularly important. The bored pile is widely used in the construction of the substation due to the characteristics of high bearing capacity, flexible adjustment of the length and diameter of the pile, and construction in different strata.

[0003] The mud is the main waste produced in the construction process of the bored pile, which not only contains solid substances such as clay, sandy soil, gravel soil, weathered rock, mineral and rock debris, but also contains a large amount of water. At the same time, the mud is difficult to dry naturally due to the high water content, and if it is not treated in time, it will not only affect the construction of the subsequent project, but also easily cause environmental pollution and water pollution.

[0004] At present, the common mud treatment method is to directly transport the mud to the designated area for simple landfill and storage by vehicles. Since the mud is directly stored without solidification and reduction treatment, a large amount of storage space is required. With the increase of mud production, most mud storage areas cannot meet the storage of new mud; and simply landfilling the mud with high water content has many hidden dangers, such as affecting the normal approach operation of vehicles and landfill machinery.

[0005] Therefore, it is of great significance to develop a mud treatment agent capable of solidifying and reducing the mud. SUMMARY

[0006] The present application aims to provide a mud treatment agent capable of solidifying and reducing the mud, and a preparation method and application thereof.

[0007] In the present application, the solidification and reduction of the mud refers to reducing the water content of the dehydrated mud cake obtained by mud-water separation.

[0008] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0009] In the first aspect, the present application provides a mud treatment agent, which comprises, by weight fraction:

[0010] 100 parts of a mud and sand coagulating agent, 20-40 parts of a solidifying agent, and 5-15 parts of a heavy metal ion removing agent;

[0011] The mud and sand coagulating agent is sodium polyacrylate, alginate and iron salt with a mass ratio of 10: (1-4) : (0.5-2) ;

[0012] The solidifying agent is HEC-1.

[0013] The preparation method of the heavy metal ion removing agent is that carboxymethyl chitosan and cysteine are subjected to grafting reaction in a mass ratio of 10:(1-3) to obtain the heavy metal ion removing agent.

[0014] The mud treating agent can promote the aggregation of solids in the mud, thereby facilitating the separation of the mud and water, reducing the water content of the dewatered cake obtained by separating the mud and water, and achieving the solidification reduction of the mud.

[0015] Preferably, the alginate is at least one of sodium alginate, potassium alginate and ammonium alginate.

[0016] Preferably, the iron salt is at least one of ferric chloride, ferric nitrate and ferric sulfate.

[0017] In the present application, the solidifying agent HEC-1 is a high-strength and high-water-resistance soil solidifying agent of model HEC-1 produced by Wuhan Hydroelectric University, which is a dark gray powdery material.

[0018] Preferably, the preparation method of the heavy metal ion removing agent is that carboxymethyl chitosan is added into a solvent, then cysteine, EDC [1-ethyl-(3-dimethylaminopropyl) carbonyl diimide] and NHS (N-hydroxysuccinimide) are added, grafting reaction is carried out by heating, EDC, NHS and unreacted cysteine are removed by dialysis, and drying is performed to obtain the heavy metal ion removing agent.

[0019] The mass ratio of the carboxymethyl chitosan and the cysteine is 10:(1-3).

[0020] Preferably, the mass ratio of the carboxymethyl chitosan, the cysteine, the EDC and the NHS is 10:(1-3):(0.02-0.6):(0.04-0.7).

[0021] More preferably, the temperature for the grafting reaction by heating is 30-70 DEG C, and the time is 3-6 h.

[0022] More preferably, the solvent is one or more of water and ethanol; when the solvent is a mixture of water and ethanol, the volume ratio of water to ethanol is 1:(0.1-1).

[0023] More preferably, the temperature for the drying is 60-90 DEG C.

[0024] In a second aspect, the present application provides a preparation method of a mud treating agent, comprising:

[0025] Mixing the components to obtain the mud treating agent.

[0026] Thirdly, the present invention provides an application of a mud treatment agent in mud treatment.

[0027] Fourthly, the present invention provides a mud treatment method, comprising:

[0028] Add mud treatment agent to the mud, stir and mix, and then separate the mud and water to obtain dewatered mud cake.

[0029] The mud treatment method of the present invention can transform mud with a water content of 55-85% into dewatered mud cake with a water content of <20%, and the dewatered mud cake has an unconfined compressive strength of >100kPa after 7 days. It does not turn into mud when it comes into contact with water and does not cause secondary pollution.

[0030] Preferably, the water content of the mud is 55-85%.

[0031] In this invention, the method for determining the water content of the mud is as follows: first, weigh the mud by weight m. o (Unit: kg), heat and dry the mud to obtain solid particles of the mud, weigh the solid particles of the mud m1 (unit: kg), and use the formula (m o -m1) / m o The water content of the mud is obtained by calculating ×100%.

[0032] Preferably, the mud comprises the following components by mass percentage: 55-85% water, with the balance being solid particles.

[0033] More preferably, the solid particles are at least one of drill cuttings, gravel, clay particles, organic matter, and soluble salts.

[0034] The mud described in this invention is the main waste generated during the construction of bored piles.

[0035] Preferably, the mass ratio of the mud to the mud treatment agent is 100:(0.2-90).

[0036] Preferably, the stirring speed is 200-600 rpm and the time is 2-8 hours.

[0037] Preferably, the mud-water separation is achieved by a diaphragm filter press, and the pressure of the mud-water separation is 0.5-3.0 MPa, and the time is 1-5 h.

[0038] Preferably, the slurry is first subjected to gravity separation in a sedimentation tank to remove lumpy solid impurities before use, and then subjected to a bar screen to remove floating debris.

[0039] Fifthly, the present invention provides the application of the above-mentioned mud treatment method in environmental protection.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] The mud treatment agent of the present invention can promote the aggregation of solids in the mud, thereby facilitating mud-water separation and reducing the water content of the dewatered mud cake obtained after mud-water separation, thereby achieving solidification and weight reduction of the mud.

[0042] The mud treatment method of the present invention can transform mud with a water content of 55-85% into dewatered mud cake with a water content of <20%, and make the dewatered mud cake have an unconfined compressive strength of >100kPa after 7 days. It does not become muddy or lose strength after contact with water, and there is no secondary pollution. Detailed Implementation

[0043] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0044] The reagents used in the various embodiments and comparative examples of this invention are as follows:

[0045] The manufacturer of sodium polyacrylate is Shanghai Maclean, and the product code is 767418-500g;

[0046] The manufacturer of sodium alginate is Shanghai Maclean, and the product code is S817374-500g.

[0047] The manufacturer of the consolidating agent is Wuhan University of Hydraulic and Electric Engineering, and the product model is HEC-1.

[0048] The manufacturer of carboxymethyl chitosan is Shanghai Maclean, and the product code is C832672-100g;

[0049] In this invention, the method for determining the water content of the mud is as follows: first, weigh the mud by weight m. o (Unit: kg), heat and dry the mud to obtain solid particles of the mud, weigh the solid particles of the mud m1 (unit: kg), and use the formula (m o -m1) / m o The water content of the mud is obtained by calculating ×100%.

[0050] Example 1

[0051] This embodiment provides a mud treatment agent, which, by weight, comprises:

[0052] 100 parts of sediment flocculant A1, 30 parts of solidifying agent, and 10 parts of heavy metal ion removal agent B1;

[0053] The sediment-flooding agent A1 is sodium polyacrylate, sodium alginate, and ferric chloride in a mass ratio of 10:2.5:1.

[0054] The consolidating agent is HEC-1;

[0055] The preparation method of the heavy metal ion removing agent B1 is: 10 g of carboxymethyl chitosan is ultrasonically dissolved in a 100 mL water and ethanol mixture with a volume ratio of 1:0.1, then 2 g of cysteine, 0.2 g of EDC [1-ethyl-(3-dimethylaminopropyl) carbonyl diimide] and 0.3 g of NHS (N-hydroxysuccinimide) are added, a grafting reaction is carried out at 45°C for 5 h, EDC, NHS and unreacted cysteine are removed by dialysis bag dialysis, and drying is carried out at 85°C to obtain the heavy metal ion removing agent B1.

[0056] The EDC and NHS are first dissolved in 2 mL of DMSO, and then added to the reaction system.

[0057] A preparation method of a mud treatment agent, comprising:

[0058] The components are mixed to obtain the mud treatment agent.

[0059] A mud treatment method, comprising the following steps:

[0060] 100 kg of mud, which has been subjected to gravity separation to remove block-shaped solid impurities in a sedimentation tank and then subjected to removal of floating impurities by a grating machine, is placed in a homogenization tank, 1 kg of the mud treatment agent is added, and stirring and mixing are carried out at a speed of 400 rpm for 4 h, mud-water separation is carried out by a diaphragm filter press at 1.8 MPa for 2 h, and a dewatered mud cake is obtained.

[0061] The mud is a main waste generated in the construction process of a drilling pile, and has a water content of 75%; the mud comprises the following components in terms of mass percentage: 75% of water, and the balance of solid particles; the solid particles are drill cuttings, gravel, silt, organic matter and soluble salt.

[0062] Examples 2-7 and Comparative Examples 1-8

[0063] Examples 2-7 and Comparative Examples 1-8 provide different mud treatment agents, which are different from Example 1 in that the components and amounts of the mud treatment agents are different, and the rest are consistent with Example 1, and the specific contents are shown in the following table:

[0064] Table 1 Formulation of mud treatment agents in Examples 1-7 and Comparative Examples 1-8

[0065]

[0066]

[0067] In the above table:

[0068] A1 indicates that the mud and sand coagulating agent is sodium polyacrylate, sodium alginate and ferric chloride at a mass ratio of 10:2.5:1;

[0069] A2 represents that the sediment flocculating agent is sodium polyacrylate, sodium alginate and ferric chloride with a mass ratio of 10:15:1;

[0070] A3 represents that the sediment flocculating agent is sodium polyacrylate and ferric chloride with a mass ratio of 10:1, i.e. without sodium alginate;

[0071] B1 represents that the heavy metal ion removing agent is the product of grafting reaction of 10 g carboxymethyl chitosan and 2 g cysteine, i.e. the mass ratio of carboxymethyl chitosan and cysteine is 10:2;

[0072] B2 represents that the heavy metal ion removing agent is the product of grafting reaction of 10 g carboxymethyl chitosan and 1 g cysteine, i.e. the mass ratio of carboxymethyl chitosan and cysteine is 10:1;

[0073] B3 represents that the heavy metal ion removing agent is the product of grafting reaction of 10 g carboxymethyl chitosan and 3 g cysteine, i.e. the mass ratio of carboxymethyl chitosan and cysteine is 10:3;

[0074] B4 represents that the heavy metal ion removing agent is carboxymethyl chitosan which has not been grafted with cysteine;

[0075] B5 represents that the heavy metal ion removing agent is the product of grafting reaction of 10 g carboxymethyl chitosan and 3 g cysteine, i.e. the mass ratio of carboxymethyl chitosan and cysteine is 10:10;

[0076] B6 represents that the heavy metal ion removing agent is the product of grafting reaction of 10 g carboxymethyl chitosan and 2 g methionine, i.e. the mass ratio of carboxymethyl chitosan and cysteine is 10:2.

[0077] Performance test

[0078] The following performance tests were conducted on the dewatered cement cakes prepared in each example and comparative example:

[0079] (1) Water content test

[0080] The weight m (unit: kg) of the dewatered cement cake of each example or comparative example was weighed, the cement cake was heated and dried at 85°C for 48 h, and the weight m t of the dried cement cake was weighed, and the water content of the dewatered cement cake of each example or comparative example was calculated by the formula (m-m t ) / m x 100%;

[0081] (2) 7-day unconfined compressive strength test

[0082] The dewatered cement cakes of each embodiment or comparative example were made into samples of 150mm×150mm×150mm, cured for 6 days at 20±2℃ and relative humidity>95%, and then soaked for 1 day. The 7-day unconfined compressive strength of the dewatered cement cakes of each embodiment or comparative example was tested at an unconfined compressive rate of 1mm / min.

[0083] (3) Mudification test

[0084] The dewatered cakes from each embodiment or comparative example were left to stand for 1 day, and then immersed in 100L of water for 5 hours. The water was observed to become significantly turbid, and the dewatered cakes were pressed to observe whether they softened. If the water became significantly turbid and the dewatered cakes softened, it was considered that the dewatered cakes had become muddy. Otherwise, the dewatered cakes had not become muddy.

[0085] The experimental results are shown in the table below:

[0086] Table 2. Performance test results of dewatered cake in each embodiment and comparative example.

[0087] Moisture content / % 7-day unconfined compressive strength / kPa Whether to occur mud Example 1 10.0 120.5 No Example 2 14.1 112.3 No Example 3 13.8 113.5 No Example 4 12.5 116.6 No Example 5 12.9 115.9 No Example 6 14.7 110.7 No Example 7 15.0 109.5 No Comparative Example 1 55.0 71.0 Yes Comparative Example 2 46.9 89.2 Yes Comparative Example 3 49.5 83.4 Yes Comparative Example 4 45.0 90.1 Yes Comparative Example 5 47.3 87.8 Yes Comparative Example 6 47.7 87.0 Yes Comparative Example 7 46.5 89.5 Yes Comparative Example 8 48.4 85.5 Yes

[0088] As shown in the table above, the mud treatment agent of the present invention can promote the aggregation of solids in the mud, thereby facilitating mud-water separation and reducing the water content of the dewatered mud cake obtained after mud-water separation, thus achieving solidification and weight reduction of the mud. Specifically:

[0089] (1) By comparing the data of Examples 1-3, 6-7 and Comparative Examples 1-2, 6, it can be seen that in the mud treatment agent of the present invention, only when the heavy metal ion removal agent and the solidifying agent are within a specific dosage range can mud with a water content of 55-85% be transformed into dewatered cake with a water content of <20%, and the dewatered cake has an unconfined compressive strength of >100kPa after 7 days and does not become muddy after contact with water;

[0090] (2) By comparing the data of Examples 1, 4-5 and Comparative Examples 3-5, it can be seen that in the mud treatment agent of the present invention, only when the carboxymethyl chitosan and cysteine ​​of the synthetic heavy metal ion removal agent are within a specific mass ratio range can mud with a water content of 55-85% be transformed into dewatered cake with a water content of <20%, and the dewatered cake has an unconfined compressive strength of >100kPa after 7 days and does not become muddy after contact with water.

[0091] (3) By comparing the data of Example 1 and Comparative Examples 7-8, it can be seen that in the mud treatment agent of the present invention, only when the mud flocculant contains sodium polyacrylate, alginate and iron salt, and the sodium polyacrylate, alginate and iron salt are within a specific mass ratio range, can mud with a water content of 55-85% be transformed into dewatered cake with a water content of <20%, and the dewatered cake has an unconfined compressive strength of >100kPa after 7 days, and does not become muddy after contact with water.

[0092] Finally, it should be noted that the above examples are merely intended to illustrate the technical solutions of the present application and not to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A mud treatment agent, characterized in that, Calculated by weight, including: 100 parts sediment flocculant, 20-40 parts solidifying agent, 5-15 parts heavy metal ion removal agent; The sediment flocculant is sodium polyacrylate, alginate and iron salt in a mass ratio of 10:(1-4):(0.5-2); The preparation method of the heavy metal ion removal agent is as follows: add carboxymethyl chitosan to a solvent, then add cysteine, EDC and NHS, heat to carry out a grafting reaction, dialyze to remove EDC, NHS and unreacted cysteine, and dry to obtain the heavy metal ion removal agent. The mass ratio of carboxymethyl chitosan, cysteine, EDC, and NHS is 10:(1-3):(0.02-0.6):(0.04-0.7).

2. The mud treatment agent as described in claim 1, characterized in that, The consolidating agent is HEC-1.

3. The method for preparing the mud treatment agent according to any one of claims 1-2, characterized in that, include: Mix the components to obtain the mud treatment agent.

4. The application of the mud treatment agent according to any one of claims 1-2 in mud treatment.

5. A method for treating mud, characterized in that, include: Add the mud treatment agent according to any one of claims 1-2 to the mud, stir and mix, and separate the mud and water to obtain dewatered mud cake.

6. The mud treatment method as described in claim 5, characterized in that, The water content of the mud is 55-85%.

7. The mud treatment method as described in claim 5, characterized in that, The mass ratio of the mud to the mud treatment agent is 100:(0.2-90).

8. The application of the mud treatment method according to any one of claims 5-7 in environmental protection.

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