A new type of bio-enzyme-cement composite solidifying agent for slag treatment and application thereof

Abstract

The application provides a bio-enzyme-cement composite solidifying agent suitable for slag treatment and application thereof, and belongs to the technical field of solidifying agents.The bio-enzyme-cement composite solidifying agent is composed of a bio-enzyme mixed solution and cement, which are independently stored before use.The bio-enzyme mixed solution comprises cellulase and alkaline protease, the cellulase is from a cellulase reagent, and the mass ratio of the cellulase reagent to the alkaline protease is 1:0.9-1:1.1; and the weight ratio of the bio-enzyme mixed solution to the cement is 1:400-3:2000.The application has the characteristics of green, environmental friendliness and sustainability, and the new bio-enzyme-cement composite solidifying agent can greatly reduce the amount of traditional solidifying agents such as lime cement compared with traditional solidifying agents.The new bio-enzyme-cement composite solidifying agent adopts a bio-enzyme and inorganic compound formula, improves the early strength of the solidifying agent, and has great prospects in actual engineering.

Description

Technical Field

[0001] This invention relates to the field of curing agent technology, and more specifically, to a bio-enzyme-cement composite curing agent suitable for slag and soil treatment and its application. Background Technology

[0002] In recent years, with the rapid development of infrastructure and the rise of high-rise buildings in cities, the amount of construction waste generated by urban construction has increased significantly. For every 10,000 cubic meters of building, 500 to 600 tons of construction waste are generated. In the past, construction waste was generally disposed of through landfill or dumping into the ocean. Such methods not only cause serious environmental pollution but also waste soil resources.

[0003] Currently, the main method for utilizing construction waste is through solidification treatment. Solidified waste can be improved into high-quality fill material and applied to road and foundation construction projects, offering excellent economic benefits. Existing solidifying agents are mainly classified into four types: ionic solidifying agents, inorganic solidifying agents, organic solidifying agents, and bio-enzyme solidifying agents. Inorganic solidifying agents, including cement and lime, are commonly used in engineering. However, these inorganic solidifying agents suffer from problems such as high energy consumption and significant pollution during preparation. Furthermore, their initial solidification effect is not significant, and the solidification effect is unstable. Therefore, a new type of solidifying agent is urgently needed to overcome these problems. Bio-enzyme solidifying agents are multi-enzyme products fermented from organic matter. Under the catalysis of enzymes, these solidifying agents rapidly form a hard structural layer on the surface of soil particles. Combined with external compression, this makes the soil denser, thereby increasing soil strength. Compared to traditional bio-enzymes, this method can effectively reduce costs. Summary of the Invention

[0004] To address the problems in existing technologies, this invention proposes a novel bio-enzyme-cement composite curing agent suitable for slag and soil treatment and its application. Compared with traditional inorganic curing agents, the novel bio-enzyme-cement composite curing agent can reduce the amount of cement used, reduce environmental pollution, improve the early strength of the cured soil, and also reduce costs. Furthermore, by changing the type and concentration of the bio-enzyme, different types of soil can be effectively cured.

[0005] The bio-enzyme-cement composite curing agent for slag and soil treatment described in this invention is composed of a bio-enzyme mixture solution and cement, which are stored separately before use. The bio-enzyme mixture solution contains cellulase and alkaline protease. The cellulase is derived from a cellulase reagent, and the activity of the cellulase reagent is not less than 10,000 u / ml. The mass ratio of the cellulase reagent to the alkaline protease is 1:0.9 to 1:1.1. The weight ratio of the bio-enzyme mixture solution to cement is 1:400 to 3:2000.

[0006] Furthermore, the activity of the alkaline protease is not less than 50,000 u / g.

[0007] Furthermore, the cement is PO52.5 silicate cement; the cement is in powder form.

[0008] Furthermore, the mass ratio of the cellulase reagent to the alkaline protease is preferably 1:1.

[0009] Furthermore, the bio-enzyme mixture is obtained by mixing the cellulase reagent and the alkaline protease at a mass ratio of 1:0.9 to 1:1.1 and stirring until homogeneous.

[0010] This invention also proposes an application of the above-mentioned bio-enzyme-cement composite curing agent, comprising the following steps:

[0011] a) Add cement to the slag soil, wherein the mass ratio of cement to slag soil is 1:40 to 1:60. During the addition process, continuously stir the slag soil so that the cement can be evenly dispersed in the slag soil.

[0012] b) The bio-enzyme mixture is evenly sprayed onto the mixture of cement and slag and mixed evenly, wherein the mass ratio of the bio-enzyme mixture to the slag is 1:20000 to 3:10000.

[0013] c) Seal the resulting mixture and let it stand until it hardens.

[0014] Furthermore, the stirring in step b) is to stir until there is no visible layering in the solution.

[0015] Furthermore, the slag soil is slag soil with a moisture content of 23%.

[0016] It should be noted that the cellulase reagent, alkaline protease, and cement used in this invention are all commercially available.

[0017] The beneficial technical effects of this invention compared to other methods are:

[0018] (1) This invention provides a highly active bio-enzyme that can catalyze the decomposition of organic matter in soil and improve soil compressive strength. The addition of the bio-enzyme reduces the potential between soil particles, decreasing the distance between them and thus reducing the soil porosity to some extent, allowing cement hydration products to fill the pores better. Simultaneously, the addition of cement provides alkaline conditions and a large amount of calcium ions to the soil, creating an alkaline environment around microbial cells, which is conducive to the formation of calcium carbonate precipitates. The bio-enzyme promotes the cement hydration reaction, generating a large amount of CSH gel, which promotes the connection of soil particles and the formation of a clay-polymer network. Through the synergistic effect of cement and the bio-enzyme, the soil reinforcement method becomes more effective.

[0019] (2) Compared with traditional curing agents, this invention uses a lower cement content (10wt% for traditional cement) and a more inexpensive bio-enzyme (the bio-enzymes used in traditional curing agents are usually Lewis enzymes and Tauran enzymes; these bio-enzymes cost more than 1,000 yuan per liter and many are imported). This not only prevents the large amount of pollution caused by high cement content, but also reduces the high cost caused by high bio-enzyme content, resulting in excellent economic benefits. Detailed Implementation

[0020] The embodiments of the technical solution of the present invention will be described in detail below. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore merely examples and should not be used to limit the scope of protection of the present invention. It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0021] The cellulase preparation used in the following examples is cellulase FDY-2243 (purchased from Cangzhou Xiasheng Enzyme Biotechnology Co., Ltd.), which has an activity greater than 10,000 u / ml. The alkaline protease used is alkaline protease from Pangbo Biotechnology (purchased from Nanning Pangbo Bioengineering Co., Ltd.), which has an activity greater than 50,000 u / g.

[0022] Example 1

[0023] This embodiment provides a novel bio-enzyme-cement composite curing agent, which is added to the soil through the following steps:

[0024] Mix 0.005g of cellulase preparation and 0.005g of alkaline protease and stir well to obtain 0.01g of alkaline enzyme solution. Then add the alkaline enzyme solution to 46g of water and mix to obtain a mixed solution of alkaline enzyme and water. First, add 4g of cement to 200g of silt, then spray in the mixed solution of alkaline enzyme and water, shake well in a sealed bag, and let it stand for curing to achieve long-term solidification of the soil.

[0025] Example 2

[0026] This embodiment provides a novel bio-enzyme-cement composite curing agent, which is added to the soil through the following steps:

[0027] Mix 0.01g of cellulase preparation and 0.01g of alkaline protease and stir well to obtain 0.02g of alkaline enzyme solution. Then add the alkaline enzyme solution to 46g of water and mix to obtain a mixed solution of alkaline enzyme and water. First, add 4g of cement to 200g of silt, then spray in the mixed solution of alkaline enzyme and water, shake well in a bag, and let it stand for curing to achieve long-term solidification of the soil.

[0028] Example 3

[0029] This embodiment provides a novel bio-enzyme-cement composite curing agent, which is added to the soil through the following steps:

[0030] Mix 0.015g of cellulase preparation and 0.015g of alkaline protease and stir well to obtain 0.03g of alkaline enzyme solution. Then add the alkaline enzyme solution to 46g of water and mix to obtain a mixed solution of alkaline enzyme and water. First, add 4g of cement to 200g of silt, then spray in the mixed solution of alkaline enzyme and water, shake well in a bag, and let it stand for curing to achieve long-term solidification of the soil.

[0031] Example 4

[0032] This embodiment provides a novel bio-enzyme-cement composite curing agent, which is added to the soil through the following steps:

[0033] Mix 0.03g of cellulase preparation and 0.03g of alkaline protease and stir well to obtain 0.06g of alkaline enzyme solution. Then add the alkaline enzyme solution to 46g of water and mix to obtain a mixed solution of alkaline enzyme and water. First, add 4g of cement to 200g of silt, then spray in the mixed solution of alkaline enzyme and water, shake well in a bag, and let it stand for curing to achieve long-term solidification of the soil.

[0034] Example 5

[0035] This embodiment provides a novel bio-enzyme-cement composite curing agent, which is added to the soil through the following steps:

[0036] Mix 0.005g of cellulase preparation and 0.005g of alkaline protease and stir well to obtain 0.01g of alkaline enzyme solution. Then add the alkaline enzyme solution to 46g of water and mix to obtain a mixed solution of alkaline enzyme and water. First, add 4g of cement to 200g of silty clay, then spray in the mixed solution of alkaline enzyme and water, shake well in a bag, and let it stand for curing to achieve long-term solidification of the soil.

[0037] Example 6

[0038] This embodiment provides a novel bio-enzyme-cement composite curing agent, which is added to the soil through the following steps:

[0039] Mix 0.01g of cellulase preparation and 0.01g of alkaline protease and stir well to obtain 0.02g of alkaline enzyme solution. Then add the alkaline enzyme solution to 46g of water and mix to obtain a mixed solution of alkaline enzyme and water. First, add 4g of cement to 200g of silty clay, then spray in the mixed solution of alkaline enzyme and water, shake well in a bag, and let it stand for curing to achieve long-term solidification of the soil.

[0040] Example 7

[0041] This embodiment provides a novel bio-enzyme-cement composite curing agent, which is added to the soil through the following steps:

[0042] Mix 0.015g of cellulase preparation and 0.015g of alkaline protease and stir well to obtain 0.03g of alkaline enzyme solution. Then add the alkaline enzyme solution to 46g of water and mix to obtain a mixed solution of alkaline enzyme and water. First, add 4g of cement to 200g of silty clay, then spray in the mixed solution of alkaline enzyme and water, shake well in a bag, and let it stand for curing to achieve long-term solidification of the soil.

[0043] Example 8

[0044] This embodiment provides a novel bio-enzyme-cement composite curing agent, which is added to the soil through the following steps:

[0045] Mix 0.03g of cellulase preparation and 0.03g of alkaline protease and stir well to obtain 0.06g of alkaline enzyme solution. Then add the alkaline enzyme solution to 46g of water and mix to obtain a mixed solution of alkaline enzyme and water. First, add 4g of cement to 200g of silty clay, then spray in the mixed solution of alkaline enzyme and water, shake well in a bag, and let it stand for curing to achieve long-term solidification of the soil.

[0046] Example 9

[0047] This embodiment provides a novel bio-enzyme-cement composite curing agent, which is added to the soil through the following steps:

[0048] Mix 0.005g of cellulase preparation and 0.005g of alkaline protease and stir well to obtain 0.01g of alkaline enzyme solution. Then add the alkaline enzyme solution to 46g of water and mix to obtain a mixed solution of alkaline enzyme and water. First, add 4g of cement to 200g of clay, then spray in the mixed solution of alkaline enzyme and water, shake well in a bag, and let it stand for curing to achieve long-term solidification of the soil.

[0049] Example 10

[0050] This embodiment provides a novel bio-enzyme-cement composite curing agent, which is added to the soil through the following steps:

[0051] Mix 0.01g of cellulase preparation and 0.01g of alkaline protease and stir well to obtain 0.02g of alkaline enzyme solution. Then add the alkaline enzyme solution to 46g of water and mix to obtain a mixed solution of alkaline enzyme and water. First, add 4g of cement to 200g of clay, then spray in the mixed solution of alkaline enzyme and water, shake well in a bag, and let it stand for curing to achieve long-term solidification of the soil.

[0052] Example 11

[0053] This embodiment provides a novel bio-enzyme-cement composite curing agent, which is added to the soil through the following steps:

[0054] Mix 0.015g of cellulase preparation and 0.015g of alkaline protease and stir well to obtain 0.03g of alkaline enzyme solution. Then add the alkaline enzyme solution to 46g of water and mix to obtain a mixed solution of alkaline enzyme and water. First, add 4g of cement to 200g of clay, then spray in the mixed solution of alkaline enzyme and water, shake well in a bag, and let it stand for curing to achieve long-term solidification of the soil.

[0055] Example 12

[0056] This embodiment provides a novel bio-enzyme-cement composite curing agent, which is added to the soil through the following steps:

[0057] Mix 0.03g of cellulase preparation and 0.03g of alkaline protease and stir well to obtain 0.06g of alkaline enzyme solution. Then add the alkaline enzyme solution to 46g of water and mix to obtain a mixed solution of alkaline enzyme and water. First, add 4g of cement to 200g of clay, then spray in the mixed solution of alkaline enzyme and water, shake well in a bag, and let it stand for curing to achieve long-term solidification of the soil.

[0058] Comparative Example 1

[0059] This comparative example provides a method for solidifying soil, which involves adding the following steps to the soil: Add 4g of cement to 200g of silt, mix thoroughly, then add 46g of water, shake well in a bag, and allow to stand for curing to achieve long-term solidification of the soil.

[0060] Comparative Example 2

[0061] This comparative example provides a method for solidifying soil, which involves adding the following steps to the soil: Add 4g of cement to 200g of silty clay, mix thoroughly, then add 46g of water, shake well in a bag, and allow to stand for curing to achieve long-term solidification of the soil.

[0062] Comparative Example 3

[0063] This comparative example provides a method for solidifying soil, which involves adding the following steps to the soil: Add 4g of cement to 200g of clay, mix thoroughly, then add 46g of water, shake well in a bag, and allow to stand for curing to achieve long-term solidification of the soil.

[0064] Comparative Example 4

[0065] This comparative example provides a method for soil solidification, which involves adding the following steps to the soil: Add 8g of lime to 200g of silt, mix thoroughly, then add 46g of water, shake well in a bag, and allow to stand for curing to achieve long-term soil solidification.

[0066] Comparative Example 5

[0067] This comparative example provides a method for solidifying soil, which involves adding the following steps to the soil: Add 8g of lime to 200g of silty clay, mix thoroughly, then add 46g of water, shake well in a bag, and allow to stand for curing to achieve long-term solidification of the soil.

[0068] Comparative Example 6

[0069] This comparative example provides a method for solidifying soil, which involves adding the following steps to the soil: Add 8g of lime to 200g of clay, mix thoroughly, then add 46g of water, shake well in a bag, and allow to stand for curing to achieve long-term solidification of the soil.

[0070] The above comparative examples used two soil solidification methods: cement and lime for long-term soil solidification. Both methods are commonly used in practical engineering applications.

[0071] The unconfined compressive strength of the solidified soil in the examples and comparative examples was tested:

[0072] The samples from the examples and comparative examples were added to the three-valve membrane in five separate additions, with compaction performed after each addition. After demolding, cylindrical specimens were obtained. These specimens were wrapped in an impermeable membrane and placed in a curing chamber, where they were cured for one day at 20°C and 95% humidity. Finally, the specimens were placed in a universal pressure tester to measure the unconfined compressive strength of the soil samples.

[0073] Table 4 Unconfined compressive strength of silty soil after 1 day of curing

[0074] Group Unconfined compressive strength (kPa) Example 1 71.23 Example 2 71.00 Example 3 70.69 Example 4 54.19 Comparative Example 1 36.23 Comparative Example 4 41.88

[0075] Table 5 Unconfined compressive strength of silty clay after 1 day of curing

[0076] Group Unconfined compressive strength (kPa) Example 5 250.38 Example 6 258.42 Example 7 267.32 Example 8 253.58 Comparative Example 2 218.38 Comparative Example 5 168.54

[0077] Table 6 Unconfined compressive strength of clay after 1 day of curing

[0078] Group Unconfined compressive strength (kPa) Example 9 326.41 Example 10 347.96 Example 11 320.13 Example 12 310.93 Comparative Example 3 292.43 Comparative Example 6 235.99

[0079] As shown in Tables 1, 2, and 3, the novel bio-enzyme-cement composite curing agent provided by this invention can significantly improve the unconfined compressive strength of cured soil. The most significant improvement in the unconfined compressive strength of the cured soil occurs when the bio-enzyme accounts for 0.01%-0.015% of the soil mass.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for treating slag soil based on a bio-enzyme-cement composite solidifying agent, characterized by, The bio-enzyme-cement composite curing agent is composed of a bio-enzyme mixed solution and cement, which are independently stored before use; the bio-enzyme mixed solution comprises cellulase and alkaline protease, the cellulase is from a cellulase reagent, the activity of the cellulase reagent is not less than 10000 u / ml, the mass ratio of the cellulase reagent to the alkaline protease is 1:0.9-1:1.1, the weight ratio of the bio-enzyme mixed solution to the cement is 1:400-3:2000, and the activity of the alkaline protease is not less than 50000 U / g. The method for treating the slag soil comprises the following steps: a) adding cement into the slag soil, the mass ratio of the cement to the slag soil being 1:40-1:60, and continuously stirring the slag soil during the adding process so that the cement can be uniformly dispersed into the slag soil; b) adding the bio-enzyme mixed solution into water and stirring uniformly to form a bio-enzyme and water mixed solution, and uniformly spraying the bio-enzyme and water mixed solution on the mixture of the cement and the slag soil and mixing uniformly, the mass ratio of the bio-enzyme mixed solution to the slag soil being 1:20000-3:10000; c) sealing the obtained mixture and standing until the curing is completed.

2. The method of claim 1, wherein The bio-enzyme mixed solution is obtained by mixing the cellulase reagent and the alkaline protease according to a mass ratio of 1:0.9-1:1.1 and stirring uniformly.

3. The method of claim 1, wherein the slag is a steelmaking slag. The cement is po52.5 Portland cement, and the cement is in the form of powder.

4. The method of claim 1, wherein the slag is a steelmaking slag. The mass ratio of the cellulase reagent to the alkaline protease is 1:

1.

5. The method of claim 1, wherein the slag is a steelmaking slag. The stirring uniformly in step b) is stirring until there is no stratification in the solution.

6. The method of claim 1, wherein The slag soil is a slag soil with a water content of 23%.