Flying dust suppression method for spoil slope

Abstract

The invention discloses a raised dust suppression method for a spoil slope. The raised dust suppression method for the spoil slope comprises the following steps: uniformly spraying a magnesium oxide solution on the surface of the spoil slope, then spraying a urea solution on the surface of the spoil slope, and maintaining the spoil slope for more than 12 hours, the steps are repeated for multiple times so as to conduct multiple rounds of treatment on the spoil slope; wherein the urea solution further comprises urease bacteria, and the urease activity of the urease bacteria is larger than 6 mM urea / min; in each round of treatment, the mass ratio of urea in the sprayed urea solution to magnesium oxide in the sprayed magnesium oxide solution is (60-240): (15-32). According to the method, the functions of inhibiting flying dust and improving the air quality in a long-acting manner can be achieved; meanwhile, the method can be flexibly applied to a construction site and has the characteristics of low cost, simplicity and convenience in operation, safety, environment friendliness and the like.

Description

Technical Field

[0001] The invention relates to a method for suppressing dust from an abandoned soil slope. Background Art

[0002] Earthwork is a crucial part of infrastructure construction. However, with the acceleration of urbanization and the expansion of construction scale, the dust pollution problem caused by abandoned soil slopes at construction sites has become increasingly prominent, causing serious harm to the surrounding environment and residents' health.

[0003] Abandoned soil slope refers to an artificial bare soil slope or earth accumulation body caused by construction activities such as earth excavation and slag dumping, usually located at construction sites in urban suburbs or rural areas. Mechanical excavation, movement, transportation and other engineering disturbances make the soil exposed on the slope surface extremely susceptible to wind action and form dust. On the one hand, the generation of dust pollutes the air quality and ecological environment, affecting people's health and normal activities; on the other hand, it may also lead to a decrease in soil fertility, damage to vegetation, and even induce land desertification, posing a serious threat to the sustainable development of the region.

[0004] According to past experience, abandoned soil slopes are often piled up for a long time without being handled in time, which further aggravates the dust pollution problem. At present, the solutions to this problem are still relatively limited. Traditional dust control methods mainly include watering, dust net covering and slope vegetation planting, but these methods have their own obvious limitations. For example, the effect of watering dust removal is unstable and has poor durability. It needs to be repeated many times a day. Its large dependence on and consumption of water resources is also a problem that cannot be ignored. Dust net covering is the most commonly used. However, due to long-term exposure to sunlight and changeable climate, dust nets are prone to aging and failure, and their durability is difficult to be guaranteed in the long term. Vegetation planting has a long cycle, high maintenance costs, and certain requirements for soil quality and soil fertility. It is not suitable as a dust suppression measure for temporary slopes.

[0005] Therefore, it is urgent to develop an efficient, long-term and stable dust suppression technology for abandoned soil slopes. Summary of the invention

[0006] In view of the above technical problems, the purpose of the present invention is to provide a dust suppression method for abandoned soil slopes, which can play a long-term role in suppressing dust and improving air quality; at the same time, it can be flexibly applied at construction sites and has the characteristics of low cost, easy operation, safety and environmental protection.

[0007] The present invention provides a method for suppressing dust from a spoil slope, comprising the following steps:

[0008] The magnesium oxide solution is evenly sprayed on the surface of the spoil slope, and the urea solution is then sprayed on the surface of the spoil slope, and the spoil slope is cured for more than 12 hours;

[0009] Repeat the above steps multiple times to process the spoil slope in multiple rounds;

[0010] The urea solution further comprises urease bacteria, and the urease activity of the urease bacteria is greater than 6 mM urea / min; in each round of treatment, the mass ratio of urea in the sprayed urea solution to magnesium oxide in the magnesium oxide solution is (60-240): (15-32).

[0011] In some preferred embodiments, in each round of treatment, the mass ratio of urea in the sprayed urea solution to magnesium oxide in the magnesium oxide solution is (100-180):20.

[0012] In some preferred embodiments, the concentration of urea in the urea solution is 60 g / L to 240 g / L; the concentration of magnesium oxide in the magnesium oxide solution is 15 g / L to 32 g / L.

[0013] In some preferred embodiments, in each round of treatment, the spraying amount of the magnesium oxide solution is 4L / m 2 ~10L / m 2 The spraying amount of the urea solution is 4L / m 2 ~10L / m 2 .

[0014] In some preferred embodiments, the mass content of active magnesium oxide in the magnesium oxide used in the magnesium oxide solution is greater than 45%.

[0015] In some more preferred embodiments, the mass content of active magnesium oxide in the magnesium oxide used in the magnesium oxide solution is 65% to 80%.

[0016] In some preferred embodiments, the spoil slope is treated for 3 to 10 rounds.

[0017] In some preferred embodiments, the magnesium oxide solution and the urea solution are sprayed between 17:00 and 19:00, and then the abandoned soil slope is maintained; the next day, the magnesium oxide solution and the urea solution are sprayed between 17:00 and 19:00 to carry out a second round of treatment.

[0018] In some preferred embodiments, the urea solution is pre-prepared and sealed and stored at room temperature for 10 to 48 hours before use; the urease-producing bacteria include Sporosarcina pasteurianus or Bacillus pasteurianus.

[0019] In some preferred embodiments, the urea solution and the magnesium oxide solution are sprayed on the surface of the spoil slope respectively by a sprinkler, a dust removal fog cannon machine and a fog cannon watering truck.

[0020] The present invention adopts the above scheme, which can achieve long-term and efficient dust suppression effect at low cost, while taking into account the significant advantages of ecology, safety, and no environmental pollution; among them, the urea that is not completely hydrolyzed in the urea solution used can also provide nitrogen fertilizer for the growth of slope vegetation in the later stage, helping to meet the ecological restoration needs of the site. The details are as follows:

[0021] (1) High efficiency, long-term and stable dust suppression effect

[0022] This method utilizes the powerful urea-dissolving ability of urea-dissolving bacteria to promote the rapid hydrolysis of urea in urea solution to produce carbonate ions, which then participate in the carbonization reaction process after the active magnesium oxide in the magnesium oxide solution is hydrated. With the assistance of urea-dissolving microorganisms, the carbonized product hydrated magnesium carbonate with strong cementing ability is mineralized in a short period of time. This type of carbonized product can significantly promote the mutual cementation between the surface soil particles of the abandoned soil slope, thereby producing a cemented hardened layer within a certain depth range of the slope surface. Studies have shown that the hardened layer has the significant advantages of strong resistance to wind erosion and rainfall erosion and good durability. Therefore, it can achieve long-term stable and efficient suppression of dust generation on the abandoned soil slope.

[0023] (2) Convenient construction and low cost

[0024] The watering equipment used in this method (sprinklers, dust removal fog cannons, fog cannon water trucks, etc.) is common equipment in construction sites and is widely used in dust reduction treatment at sites. Therefore, this method does not require additional customized special equipment, which can save equipment cost investment; in addition, the raw materials used, such as urea and magnesium oxide, are low-cost, widely available, and easy to obtain. In addition, the entire construction process is simple to operate and does not require too much manpower investment, which can save labor costs.

[0025] (3) Safe and pollution-free, helping low-carbon and sustainable development

[0026] The urea-lytic bacteria used in this method can be extracted from natural soil, and their use will not cause any damage to the ecological environment. The raw materials used also do not pose any risk of environmental pollution. In addition, it is worth noting that the urea that is not completely hydrolyzed in the urea solution used in this method can also provide nitrogen fertilizer for the growth of slope vegetation in the later stage, helping to meet the ecological restoration needs of the site; the magnesium oxide used can enhance its own carbonization by absorbing carbon dioxide in the atmosphere, improve the dust suppression effect of the abandoned soil slope, and also has a certain carbon absorption and carbon sequestration potential, which helps the country's carbon reduction strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0028] Figure 1 A flow chart of a method for suppressing dust on a spoil slope according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0030] In view of the problems of poor durability, high construction cost, and difficult maintenance in the existing technology for dust suppression on abandoned soil slopes, the following implementation method provides a dust suppression method for abandoned soil slopes based on microbial mineralization. This method can achieve long-term and efficient dust suppression effects at low cost, while taking into account the significant advantages of ecology, safety, and no environmental pollution. This can not only provide strong protection for the living environment and health of surrounding residents, but also help promote the sustainable development of urban construction and achieve a win-win situation of economic and environmental benefits.

[0031] The dust suppression method for the abandoned soil slope requires raw materials including: microbial (urea-lytic bacteria) solution, urea and magnesium oxide. Figure 1 The specific implementation process is as follows:

[0032] S1. Prepare urea solution in advance:

[0033] Add urea with a mass of M1 to a microbial solution with a volume of V1 in advance, use a stirrer to fully stir to completely dissolve the urea to form a urea solution with a concentration of C1, and then store the urea solution in a sealed barrel at room temperature for T hours for later use.

[0034] S2. On-site preparation and spraying of magnesium oxide solution:

[0035] When carrying out dust suppression operations at the construction site, magnesium oxide with a mass of M2 is added to water with a volume of V2, and a stirrer is used to fully stir the magnesium oxide in the aqueous solution to evenly mix the magnesium oxide to form a magnesium oxide solution with a concentration of C2; then, the magnesium oxide solution is evenly sprayed on the surface of the abandoned soil slope using commonly used watering equipment on the market (such as sprinklers, dust removal fog cannons, and fog cannon sprinkler trucks, etc.).

[0036] S3. On-site spraying of urea solution:

[0037] After step S2 is completed, the urea solution prepared in step S1 is evenly sprayed on the surface of the abandoned soil slope where the magnesium peroxide solution is sprayed by using a watering device to ensure that the entire slope surface is wetted.

[0038] S4. On-site maintenance:

[0039] In order to prevent the rapid evaporation of water in the magnesium oxide solution and urea solution sprayed on the slope surface under sunlight from affecting the dust suppression effect, steps S2 and S3 should be carried out in the evening (5 pm to 7 pm), and then naturally cured for more than 12 hours at night when the temperature is relatively low and the humidity is relatively high to complete a single round of treatment.

[0040] S5, multiple rounds of processing:

[0041] Completing the above steps S1 to S4 means completing one round of construction treatment. Repeat the above steps multiple times, and carry out 3 to 10 rounds of treatment in total, preferably 3 to 5 rounds.

[0042] Preferably, the urea-lytic bacteria in the microbial solution used in step S1 are Sporosarcina pasteurianum or Bacillus pasteurianum, which can rapidly catalyze the hydrolysis of urea.

[0043] Preferably, the urease activity of the urea-lytic bacteria in the microbial solution used in step S1 should be higher than 6 mM ureahydrolyzed / min to ensure that the urea-lytic bacteria can fully promote the hydrolysis of urea, thereby producing sufficient carbonate ions to react with magnesium oxide and promote the production of more cementing minerals. More preferably, the urease activity of the urease bacteria is greater than 10 mM ureahydrolyzed / min.

[0044] Preferably, in step S1, the urea concentration C1 is calculated according to the following formula:

[0045]

[0046] The urea concentration C1 is preferably controlled at 60 g / L to 240 g / L to ensure that the method achieves a good dust suppression effect. The urea concentration C1 is more preferably 100 g / L to 180 g / L, and further preferably 120 to 180 g / L. For example, the urea concentration in the urea solution is 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L, 120 g / L, 140 g / L, 160 g / L, 180 g / L, 200 g / L, 220 g / L or 240 g / L.

[0047] Preferably, the urea solution obtained in step S1 is stored at room temperature above 20° C. for a storage time T of 10 to 48 hours, in order to provide the urea-lytic bacteria with a suitable survival temperature and sufficient urea-lysis time.

[0048] Preferably, the mass content of active magnesium oxide in the magnesium oxide used in step S2 should be higher than 45%. More preferably, the mass content of active magnesium oxide in the magnesium oxide is 65% to 80%. For example, the mass content of active magnesium oxide is 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or 90%.

[0049] Preferably, in step S2, the magnesium oxide concentration C2 of the magnesium oxide solution is calculated according to the following formula:

[0050]

[0051] Wherein, the magnesium oxide concentration C2 in the magnesium oxide solution should be controlled in the range of 15g / L to 32g / L. More preferably, the magnesium oxide concentration C2 is 18g / L to 25g / L; further preferably, it is 20g / L to 25g / L. For example, the magnesium oxide concentration C2 is 15g / L, 16g / L, 18g / L, 19g / L, 20g / L, 22g / L, 24g / L, 25g / L, 28g / L, 30g / L or 32g / L.

[0052] The amount of magnesium oxide solution and urea solution sprayed on the surface of the spoil slope in steps S2 and S3 should be determined according to the actual situation of the spoil slope. Preferably, the spraying amount of magnesium oxide solution is 4 to 10 L / m 2 ; More preferably 4 to 6 L / m 2 The spraying amount of urea solution is 4-10L / m 2 ; More preferably 4 to 6 L / m 2 Specifically and preferably, the reference spraying amount of magnesium oxide solution and urea solution is 4.5L / m 2 The spraying ratio is 1:1 (i.e. 4.5L of magnesium oxide solution and 4.5L of urea solution are sprayed on every square meter of the abandoned soil slope surface).

[0053] Furthermore, in each round of treatment, the mass ratio of urea in the sprayed urea solution to magnesium oxide in the magnesium oxide solution is (60-240): (15-32). More preferably, in each round of treatment, the mass ratio of urea in the sprayed urea solution to magnesium oxide in the magnesium oxide solution is (100-180): 20. Under this ratio, it has a better dust suppression effect and has a good effect on the concentration of fine particles (PM 10 ) and the concentration of inhalable particulate matter (PM 2.5 ) for 24 hours to monitor PM 10and PM 2.5 The values ​​of are small.

[0054] Furthermore, the magnesium oxide solution and the urea solution are sprayed between 17:00 and 19:00, and then the abandoned soil slope is maintained; the next day, the magnesium oxide solution and the urea solution are sprayed between 17:00 and 19:00 to carry out a second round of treatment; and so on, until the set round of treatment is completed.

[0055] The present invention is described in detail below in conjunction with specific embodiments. In the following embodiments, urea solution and magnesium oxide solution are first prepared using urea-lytic bacteria and magnesium oxide, respectively, and then the magnesium oxide solution and urea solution are sprayed on the surface of the abandoned soil slope in sequence. The resulting cementing minerals can promote the mutual adhesion between soil particles and form a wind erosion-resistant hardened layer within a certain depth range on the slope surface, thereby achieving the purpose of long-term suppression of dust generation. The method of the embodiment has the significant advantages of being ecological, safe, and pollution-free while achieving efficient suppression of dust on the abandoned soil slope.

[0056] Example 1

[0057] 1) Preparation of urea solution

[0058] The urea-lytic bacteria in the microbial solution used in this embodiment is Sporosarcina pasteurii, and the urease activity is 13.3 mM urea hydrolyzed / min; a certain mass of urea is added to a certain volume of microbial solution and stirred thoroughly to prepare a urea solution with a concentration C1 of 120 g / L. After being bottled, the solution is sealed and stored indoors at an ambient temperature of 25±3°C for 48 hours.

[0059] 2) Preparation of magnesium oxide solution

[0060] The magnesium oxide used in this embodiment was tested by hydration method, and the content of active magnesium oxide in the magnesium oxide was 55.8%; the concentration C2 of the prepared magnesium oxide solution was determined to be 20g / L; that is, the mass ratio of urea in the sprayed urea solution and magnesium oxide in the magnesium oxide solution was 120:20.

[0061] 3) Spraying magnesium oxide solution

[0062] The spraying work started at 5:00 a.m. on a certain day. The prepared magnesium oxide solution was sprayed back and forth on the surface of the abandoned soil slope through a sprinkler to ensure uniform spraying. The amount of magnesium oxide solution sprayed per square meter of slope surface was 4L.

[0063] 4) Spraying urea solution

[0064] After the magnesium oxide solution is sprayed, use the spraying equipment to continue spraying the pre-prepared urea solution on the surface of the abandoned soil slope, spraying back and forth to ensure that the entire slope is sprayed evenly; the amount of urea solution sprayed per square meter of slope surface is 4L.

[0065] 5) On-site maintenance

[0066] After the spraying treatment of magnesium oxide solution and urea solution is completed, the single-round treatment process is completed by curing under natural climatic conditions until the next day.

[0067] 6) Multiple rounds of processing

[0068] The second and third rounds of spraying treatment were carried out at 5 pm on the second and third days respectively, and the construction process was as described in steps 1 to 5 above. A total of 3 rounds of treatment were carried out in this embodiment.

[0069] The concentration of fine particles (PM 10 ) and the concentration of inhalable particulate matter (PM 2.5 ) for 24 hours. The average values ​​of the 24-hour monitoring results were PM 10 =87 μg / m 3 , PM 2.5 =50μg / m 3 . After comparison, it is lower than the secondary concentration limit of the Ambient Air Quality Standard (GB 3095-2012), and meets the quality requirements of the second-class ambient air functional areas (residential areas, commercial, traffic and residential mixed areas, cultural areas, industrial areas and rural areas).

[0070] Example 2

[0071] The construction process, the amount and proportion of each raw material in this embodiment are consistent with those described in Example 1, except for the difference in the number of spraying treatment rounds. In this embodiment, a total of 5 rounds of spraying treatment were carried out.

[0072] The concentration of fine particles (PM 10 ) and the concentration of inhalable particulate matter (PM 2.5 ) for 24 hours. The average values ​​of the 24-hour monitoring results were PM 10 =60 μg / m 3 , PM 2.5 =40 μg / m 3 Compared with Example 1, both indicators have been significantly improved. By comparison, they are lower than the secondary concentration limit of the Ambient Air Quality Standard (GB 3095-2012), and meet the quality requirements of Class II ambient air functional areas (residential areas, commercial and traffic mixed areas, cultural areas, industrial areas and rural areas).

[0073] Example 3

[0074] The construction process of this embodiment is consistent with that of embodiment 1, except that the amount and proportion of raw materials are different; the details are as follows:

[0075] (1) The urea-lytic bacteria is Bacillus pasteurianus, and its urease activity is 17.8 mM urea hydrolyzed / min; the concentration C1 of the prepared urea solution is 180 g / L, the urea solution is sealed and stored at 25° C. for 48 hours;

[0076] (2) The magnesium oxide used has an active magnesium oxide content of 70.3% after hydration test; the concentration C2 of the magnesium oxide solution is set to 20 g / L; that is, the mass ratio of urea in the sprayed urea solution to magnesium oxide in the magnesium oxide solution is 180:20. (3) The amount of magnesium oxide solution and urea solution sprayed per square meter of the spoil slope surface is 5 L.

[0077] (4) A total of three rounds of spraying were carried out.

[0078] The concentration of fine particles (PM 10 ) and the concentration of inhalable particulate matter (PM 2.5 ) for 24 hours. The average values ​​of the 24-hour monitoring results were PM 10 =45 μg / m 3 , PM 2.5 =30 μg / m 3 . After comparison, it is lower than the first-level concentration limit of the Ambient Air Quality Standard (GB 3095-2012), and meets the quality requirements of Class I ambient air functional areas (nature reserves, scenic spots and other areas requiring special protection).

[0079] Comparative Example 1

[0080] (1) Preparation of urea solution

[0081] The urea-lytic bacteria in the microbial solution used in this comparative example is Sporosarcina pasteurii, and the urease activity is 13.3 mM urea hydrolyzed / min; a certain mass of urea is added to a certain volume of microbial solution and stirred thoroughly to prepare a urea solution with a concentration C1 of 120 g / L. After being bottled, the solution is sealed and stored indoors at an ambient temperature of 25±3°C for 48 hours.

[0082] (2) Preparation of magnesium oxide solution

[0083] The magnesium oxide used in this embodiment was tested by hydration method, and the active magnesium oxide content in the magnesium oxide was 55.8%; the concentration C2 of the prepared magnesium oxide solution was determined to be 20 g / L;

[0084] (3) Spraying urea solution

[0085] The spraying work started at 5:00 a.m. on a certain day. The pre-prepared urea solution was sprayed back and forth on the surface of the abandoned soil slope through a sprinkler to ensure uniform spraying. The amount of urea solution sprayed per square meter of slope surface was 4L.

[0086] (4) Spraying magnesium oxide solution

[0087] After the urea solution is sprayed, use the spraying equipment to continue spraying the magnesium oxide solution on the surface of the abandoned soil slope, spraying back and forth to ensure that the entire slope is sprayed evenly; the amount of magnesium oxide solution sprayed per square meter of slope surface is 4L.

[0088] (5) On-site maintenance

[0089] After the spraying of urea solution and magnesium oxide solution is completed, the single-round treatment process is completed by curing under natural climatic conditions until the next day.

[0090] (6) Multiple rounds of processing

[0091] The second and third rounds of spraying treatment were carried out at 5 pm on the second and third days respectively, and the construction process was as described in steps 1 to 5 above. A total of 3 rounds of treatment were carried out in this embodiment.

[0092] The concentration of fine particles (PM 10 ) and the concentration of inhalable particulate matter (PM 2.5 ) for 24 hours. The average values ​​of the 24-hour monitoring results were PM 10 =130μg / m 3 , PM 2.5 =76 μg / m 3 , both values ​​are higher than the test results of Example 1. This shows that the spraying order of magnesium oxide solution should be prior to that of urea solution in order to achieve a good dust suppression effect.

[0093] Comparative Example 2

[0094] The construction process of this comparative example is consistent with that of Example 1, except that the concentration of urea in the urea solution is different; the details are as follows:

[0095] (1) The urea concentration C1 of the prepared urea solution is 240 g / L, that is, the mass ratio of urea in the sprayed urea solution to magnesium oxide in the magnesium oxide solution is 240:20.

[0096] The concentration of fine particles (PM 10 ) and the concentration of inhalable particulate matter (PM 2.5 ) for 24 hours. The average values ​​of the 24-hour monitoring results were PM 10 =98 μg / m 3 , PM 2.5 =59 μg / m 3 , both values ​​are higher than the test results in Example 1. This shows that the mass ratio of urea in the urea solution and magnesium oxide in the magnesium oxide solution in the present invention should not be too high, otherwise it will have a negative impact on the dust suppression effect.

[0097] Comparative Example 3

[0098] The construction process of this comparative example is consistent with that of Example 1, except that the concentration of urea in the urea solution is different; the details are as follows:

[0099] (1) The urea concentration C1 of the prepared urea solution is 60 g / L, that is, the mass ratio of urea in the sprayed urea solution to magnesium oxide in the magnesium oxide solution is 60:20.

[0100] The concentration of fine particles (PM 10 ) and the concentration of inhalable particulate matter (PM 2.5 ) for 24 hours. The average values ​​of the 24-hour monitoring results were PM 10 =117 μg / m 3 , PM 2.5 =68 μg / m 3 , both values ​​are higher than the test results in Example 1. This shows that the mass ratio of urea in the urea solution and magnesium oxide in the magnesium oxide solution in the present invention should not be too low, otherwise it will have a negative impact on the dust suppression effect.

[0101] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0102] In the examples, if specific conditions are not specified, they are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used without indicating the manufacturer are conventional products that can be purchased commercially. As used herein, the term "about" is used to provide flexibility and imprecision associated with a given term, measurement or value. Those skilled in the art can easily determine the degree of flexibility of a specific variable.

[0103] Concentration, amount and other numerical data can be presented in range format herein.It should be understood that such range format is only used for convenience and simplicity, and should be flexibly interpreted as not only including the numerical value clearly described as range limit, but also including all single numerical values ​​or sub-ranges included in the range, just as each numerical value and sub-range are clearly described.For example, the numerical range of about 1 to about 4.5 should be interpreted as not only including 1 and 4.5 limit values ​​clearly described, but also including single numerals (such as 2,3,4) and sub-ranges (such as 1 to 3, 2 to 4, etc.).The same principle is applicable to the scope of only narrating a numerical value, such as "less than about 4.5", which should be interpreted as including all the above-mentioned values ​​and ranges.In addition, no matter how the breadth of the described range or feature is, this explanation should be applicable.

[0104] Any steps recited in any method or process claim may be performed in any order and are not limited to the order presented in the claims. Method+function or step+function limitations are adopted only if all of the following conditions are present in a particular claim limitation: a) explicitly recite "a method for..." or "a step for..."; b) explicitly recite the corresponding function. The structure, material, or action that supports the method+function is explicitly recited in the description herein. Therefore, the scope of the present invention should be determined solely by the appended claims and their legal equivalents, rather than by the description and examples given herein.

[0105] The above embodiment is only for illustrating the technical concept and features of the present invention, and is a preferred embodiment. Its purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for suppressing dust from an abandoned soil slope, characterized in that: The steps include: The magnesium oxide solution is evenly sprayed on the surface of the spoil slope, and the urea solution is then sprayed on the surface of the spoil slope, and the spoil slope is cured for more than 12 hours; Repeat the above steps multiple times to process the spoil slope in multiple rounds; The urea solution further comprises urease bacteria, and the urease activity of the urease bacteria is greater than 6 mM urea / min; in each round of treatment, the mass ratio of urea in the sprayed urea solution to magnesium oxide in the magnesium oxide solution is (60-240): (15-32).

2. The dust suppression method according to claim 1, characterized in that: In each round of treatment, the mass ratio of urea in the sprayed urea solution to magnesium oxide in the magnesium oxide solution is (100-180):

20.

3. The dust suppression method according to claim 1, characterized in that: The concentration of urea in the urea solution is 60 g / L to 240 g / L; the concentration of magnesium oxide in the magnesium oxide solution is 15 g / L to 32 g / L.

4. The dust suppression method according to any one of claims 1 to 3, characterized in that: In each round of treatment, the spraying amount of the magnesium oxide solution is 4L / m 2 ~10L / m 2 The spraying amount of the urea solution is 4L / m 2 ~10L / m 2 .

5. The dust suppression method according to any one of claims 1 to 3, characterized in that: The mass content of active magnesium oxide in the magnesium oxide used in the magnesium oxide solution is greater than 45%.

6. The dust suppression method according to claim 3, characterized in that: The mass content of active magnesium oxide in the magnesium oxide used in the magnesium oxide solution is 65% to 80%.

7. The dust suppression method according to any one of claims 1 to 3, characterized in that: The abandoned soil slope is treated for 3 to 10 rounds.

8. The dust suppression method according to any one of claims 1 to 3, characterized in that: The magnesium oxide solution and the urea solution are sprayed between 17:00 and 19:00, and then the abandoned soil slope is maintained; the next day, the magnesium oxide solution and the urea solution are sprayed between 17:00 and 19:00 to carry out a second round of treatment.

9. The dust suppression method according to any one of claims 1 to 3, characterized in that: The urea solution is prepared in advance and sealed and stored at room temperature for 10 to 48 hours before use; the urease bacteria include Sporosarcina pasteurianum or Bacillus pasteurianum.

10. The dust suppression method according to any one of claims 1 to 3, characterized in that: The urea solution and the magnesium oxide solution are sprayed on the surface of the abandoned soil slope respectively through a sprinkler, a dust removal fog cannon machine and a fog cannon water sprinkler truck.

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