Sandy soil improver and sandy soil improvement method

Abstract

The invention belongs to the technical field of sandy soil modifying agents, and particularly relates to a sandy soil modifying agent and a sandy soil modifying method. The sandy soil improver comprises a functional bacterium suspension and a cementing liquid, the functional bacteria in the functional bacteria turbid liquid can perform biomimetic mineralization on calcium salt in the cementing liquid to generate inorganic cement calcium carbonate (the crystal form is calcite and / or vaterite), and the inorganic cement is a cementing component widely distributed in natural soil and can maintain high cementing strength and a stable structure of the sandy soil, so that the sand stabilization effect is realized. Secondly, the formed inorganic cement is consolidated on the surface layer of the sandy soil in the form of a crust layer, the main component of the crust layer is calcium carbonate, and the calcium carbonate is white or yellowish white and light in color and can significantly reduce the solar radiation effect, so that the earth surface soil temperature rise speed of the sandy soil is slowed down, the water evaporation is slowed down, the water retention is enhanced, and the drying and hardening of the surface crust layer are slowed down; and germination and growth of plant seeds are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of sand conditioners, and in particular to a sand conditioner and a sand conditioner method. Background Art

[0002] Land desertification is an ecological and environmental problem of land degradation caused by human activities. To solve the problem of land desertification, the most studied method is the chemical sand fixation method of artificial soil improvement, which is: directly spraying chemical slurry on the surface of sand or mixing chemical slurry with other materials to form artificial soil to replace shallow sand. Among them, the main active ingredient in the chemical slurry is inorganic soil conditioner. At present, inorganic soil conditioners include biochar, fly ash, etc. This type of inorganic soil conditioner can improve the water holding capacity of soil after rainfall, but it is not obvious to alleviate the rate of temperature rise of the sand surface. Summary of the invention

[0003] In view of this, the object of the present invention is to provide a sand conditioner and a sand conditioner method. The sand conditioner of the present invention can significantly reduce the rising rate of the sand surface temperature.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a sand improver, comprising a first component and a second component;

[0006] The first component is a functional bacteria suspension, wherein the functional bacteria include one or more of Bacillus pasteurianus, Sporosarcina pasteurianus and Bacillus lentus, and the concentration of the functional bacteria suspension is 10 6 ~10 9 CFU / mL;

[0007] The second component is a cementing liquid, which includes calcium salt, urea and water;

[0008] The volume ratio of the first component to the second component is 1:1.

[0009] Preferably, the method for preparing the functional bacteria suspension comprises the following steps:

[0010] The activated bacteria are inoculated into a culture medium for cultivation to obtain the functional bacteria suspension.

[0011] Preferably, the culture medium comprises the following concentration components:

[0012] Peptone 4.5-5.5g / L, beef extract 2.5-3.5g / L, urea 18-22g / L, and the balance is distilled water.

[0013] Preferably, the culture temperature is 20-30° C., and the culture time is 12-36 h; the culture is carried out on a shaker, and the rotation speed of the shaker is 150-200 rpm.

[0014] Preferably, after the culturing, the system is centrifuged to discard the colored liquid on the upper layer and retain the bacteria on the bottom; the bacteria are diluted to obtain the functional bacteria suspension; the rotation speed of the centrifugal treatment is 2000-10000 rpm and the time is 5-25 min.

[0015] Preferably, the calcium salt comprises one or more of calcium acetate, calcium chloride and calcium sulfate; the amount ratio of the calcium salt to urea is 1:1;

[0016] In the binder solution, the concentration of calcium salt is 0.25-1 mol / L.

[0017] Preferably, the calcium salt is a regenerated calcium salt, and the regenerated calcium salt is derived from a calcium raw material, and the calcium raw material includes one or more of eggshells, shells and oyster shells.

[0018] The present invention also provides a method for improving sandy soil, comprising the following steps:

[0019] Spraying the second component and the first component sequentially onto the surface of the sand to improve the sand;

[0020] The first component and the second component are the first component and the second component in the sand conditioner described in the above technical solution.

[0021] Preferably, the second component is sprayed 3 to 5 times, and the volume ratio of the second component sprayed each time to the volume of sand is 1:6.25 to 1:15; after each spraying of the second component, it is also allowed to stand for 20 to 40 minutes.

[0022] Preferably, the first component is sprayed 3 to 12 times, and the volume ratio of the first component sprayed each time to the volume of sand is 1:6.25 to 1:15; after each spraying of the first component, it also includes standing for 12 to 48 hours.

[0023] The invention provides a sand conditioner.

[0024] The beneficial effects of the present invention are mainly manifested in that the functional bacteria in the functional bacteria suspension can bionic mineralize the calcium salt in the cementing liquid to generate inorganic cementing calcium carbonate (calcite and / or vaterite in crystal form). Inorganic cementing materials are widely distributed cementing components in natural soils, which can maintain the sandy soil with high cementing strength and stable structure, and achieve sand fixation. Moreover, calcium carbonate forms electrostatic bonds between sandy soil particles and organic matter particles, increases the attraction between sandy soil particles, produces flocculation, promotes the formation of aggregates, and also has a certain sand fixation effect. Secondly, the formed inorganic cementing material is solidified on the surface of the sandy soil in the form of a crust layer. Since the main component of the crust layer is calcium carbonate, calcium carbonate is white or yellow-white, and has a light color, it can significantly reduce the effect of solar radiation, slow down the temperature rise rate of the surface layer of the sandy soil, slow down the evaporation of soil moisture, enhance water retention, slow down the drying and hardening of the surface crust layer, and is conducive to the germination and growth of plant seeds. Furthermore, calcium carbonate is hydrophilic but almost insoluble in water. It adheres to the pores between sand particles to form a stable supporting skeleton with a certain strength, which makes the sand have certain resistance to rainfall erosion and wind erosion. In addition, the functional bacteria can also convert a large amount of free Ca in the sand into 2+ It is converted into calcium carbonate, forming soil structure, reducing the loss of calcium and soil compaction caused by the combination of soil chloride ions and calcium to form highly soluble calcium chloride. In addition, the unsolidified calcium salts in the cementing fluid, as an indispensable element for plant growth, can infiltrate into the sandy soil with the action of rainfall leaching, providing nutrients for plant growth; moreover, the unsolidified calcium salts can enter the soil through rainfall leaching, which can adjust the pH value of the soil and prevent and treat plant growth complications (slow growth) caused by calcium deficiency.

[0025] Furthermore, the culture medium comprises the following concentration components: 4.5-5.5 g / L of peptone, 2.5-3.5 g / L of beef extract, 18-22 g / L of urea, and the balance is distilled water. In the present invention, the nutrients of the culture medium are all natural organic substances, which are harmless to the soil environment.

[0026] Furthermore, after the culture, the system obtained is centrifuged, the colored liquid on the upper layer is discarded, and the bottom bacteria are retained; the bacteria are diluted to obtain the functional bacteria suspension; the rotation speed of the centrifugal treatment is 2000-10000rpm, and the time is 5-25min. The system obtained after the culture is centrifuged and the colored liquid on the upper layer is discarded, which can avoid the interference of the color of the culture medium and the bacterial metabolic waste, and can control the crystal form of the mineralized product generated by the reaction of the functional bacteria and the regenerated calcium salt; specifically: the mineralization reaction of the functional bacteria obtained without centrifugation mainly generates vaterite; when the rotation speed of the centrifugal treatment is 2000rpm, 80% of the products generated by the mineralization reaction of the functional bacteria are calcite and 20% are vaterite; when the rotation speed of the centrifugal treatment is 10000rpm, the products generated by the mineralization reaction of the functional bacteria are all calcite.

[0027] Furthermore, the calcium salt is a regenerated calcium salt, which is derived from a calcium raw material, and the calcium raw material includes one or more of eggshells, shells and oyster shells. The present invention uses one or more of eggshells, shells and oyster shells as calcium raw materials to prepare the regenerated calcium salt, thereby improving the resource utilization of such wastes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The temperature rise rate curve of the sand surface layer under natural light radiation after using the modifiers of the embodiment and the comparative example;

[0029] Figure 2 The temperature rise rate of sand at different depths under natural light radiation;

[0030] Figure 3 This is the infrared spectrum of sand under natural light radiation. DETAILED DESCRIPTION

[0031] The present invention provides a sand improver, comprising a first component and a second component;

[0032] The first component is a functional bacteria suspension, wherein the functional bacteria include one or more of Bacillus pasteurianus, Sporosarcina pasteurianus and Bacillus lentus, and the concentration of the functional bacteria suspension is 10 6 ~10 9 CFU / mL;

[0033] The second component is a cementing liquid, which includes calcium salt, urea and water;

[0034] The volume ratio of the first component to the second component is 1:1.

[0035] Unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0036] The sand soil conditioner provided by the present invention comprises a first component, wherein the first component is a functional bacteria suspension, wherein the functional bacteria comprises one or more of Bacillus pasteurianus, Bacillus pasteurianus spore Sarcina and Bacillus lentus. In the present invention, the concentration of the functional bacteria suspension is 10 6 ~10 9 CFU / mL.

[0037] In the present invention, the preparation method of the functional bacteria suspension comprises the following steps:

[0038] The activated bacteria are inoculated into a culture medium (referred to as the first culture medium) for culture (referred to as the first culture) to obtain the functional bacteria suspension.

[0039] In the present invention, the OD600 value of the activated bacteria is preferably 1.1 to 1.5. In the present invention, the specifications of the activated bacteria preferably include slant, bacterial liquid or flat plate. In the present invention, the bacteria of the slant, bacterial liquid and flat plate are activated and can be directly cultured. When not in use, they are preferably stored at 2 to 8°C; when stored for a long time, the activity of the bacteria will decrease and they need to be transferred and activated before use. In the present invention, the shelf life of the slant is preferably 1 to 3 months, the shelf life of the bacterial liquid is preferably 7 days, and the shelf life of the flat plate is preferably 7 days. In the present invention, the flat plate preferably includes a directly purchased flat plate or a flat plate obtained by activating the freeze-dried powder. In the present invention, the method for obtaining a flat plate by activating the freeze-dried powder preferably comprises the following steps: 1. preparing two flat plates; 2. opening the ampoule tube in a safety cabinet after disinfection, burning the top with an alcohol lamp, and then quickly dripping sterile water to break it, and then smashing the ampoule tube with tweezers; 3. drawing 0.5 mL of sterile water into the freeze-dried tube containing the freeze-dried powder, fully dissolving and mixing to obtain a bacterial suspension; 4. drawing 0.2 mL of the bacterial suspension into the flat plate, coating it evenly, repeating twice to obtain two flat plates; 5. culturing as required, and the bacteria can be used when they grow, which is the flat plate obtained by activating the freeze-dried powder.

[0040] In the present invention, when the specification of the activated strain is a slant or a flat plate, the transfer activation preferably includes the following steps: in a sterile environment, pick 1 to 2 loops of colonies with a sterile inoculation loop, and transfer them to a culture medium (referred to as the second culture medium) for culture (referred to as the second culture); the second culture medium preferably includes the following concentration components: peptone 4.5 to 5.5 g / L, beef extract 2.5 to 3.5 g / L, urea 18 to 22 g / L, and the balance is distilled water, and further preferably includes the following concentration components: peptone 5 g / L, beef extract 3 g / L, urea 20 g / L, and the balance is distilled water. In the present invention, the environmental temperature of the second culture is preferably 20 to 30 ° C, and the time is preferably 12 to 36 hours, specifically 12 hours, 18 hours, 24 hours, 30 hours or 36 hours. In the present invention, the second culture is preferably carried out on a shaker, and the rotation speed of the shaker is preferably 150-200 rpm, specifically preferably 150 rpm, 160 rpm, 170 rpm, 180 rpm, 190 rpm or 200 rpm.

[0041] In the present invention, when the specification of the activated strain is a bacterial liquid, the transfer activation preferably includes the following steps: in a sterile environment, using a pipette or a straw to absorb the bacterial liquid and transfer it to a culture medium (referred to as the third culture medium) for culture (referred to as the third culture). In the present invention, the composition of the third culture medium is preferably consistent with the second culture medium, which will not be repeated here. In the present invention, the volume ratio of the bacterial liquid to the third culture medium is preferably 1:100. In the present invention, the conditions of the third culture are consistent with the conditions of the second culture, which will not be repeated here.

[0042] In the present invention, the first culture medium preferably includes the following concentration components: peptone 4.5-5.5 g / L, beef extract 2.5-3.5 g / L, urea 18-22 g / L, and the balance is distilled water, and further preferably includes the following concentration components: peptone 5 g / L, beef extract 3 g / L, urea 20 g / L, and the balance is distilled water. In the present invention, the nutrients of the first culture medium are all natural organic substances, which are harmless to the soil environment.

[0043] In the present invention, the temperature of the first culture is preferably 20-30°C, and the time is preferably 12-36h, specifically 12h, 18h, 24h, 30h or 36h. In the present invention, the first culture is preferably carried out on a shaker, and the rotation speed of the shaker is preferably 150-200rpm, specifically 150rpm, 160rpm, 170rpm, 180rpm, 190rpm or 200rpm1. In the present invention, the OD600 value of the culture solution obtained by the first culture is preferably 1.204-1.534.

[0044] After the first culture, the present invention preferably further comprises: centrifuging the obtained culture solution, discarding the colored liquid on the upper layer, and retaining the bacteria on the bottom; diluting the bacteria to obtain the functional bacteria suspension. In the present invention, the rotation speed of the centrifugal treatment is preferably 2000-10000rpm, specifically 2000rpm, 3000rpm, 4000rpm, 5000rpm, 6000rpm, 7000rpm, 8000rpm, 9000rpm or 10000rpm; the time is preferably 5-25min. In the present invention, the culture solution obtained after the culture is centrifuged and the upper colored liquid is discarded, so as to avoid the interference of the color of the culture medium and the bacterial metabolic waste, and control the crystal form of the mineralized product generated by the reaction of the functional bacteria and the calcium salt; specifically: the mineralization reaction of the functional bacteria obtained without the centrifugal treatment mainly generates vaterite; when the rotation speed of the centrifugal treatment is 2000rpm, 80% of the products generated by the mineralization reaction of the functional bacteria are calcite and 20% are vaterite; when the rotation speed of the centrifugal treatment is 10000rpm, the products generated by the mineralization reaction of the functional bacteria are all calcite.

[0045] The sand conditioner provided by the present invention comprises a second component, wherein the second component is a binder, and the binder comprises a calcium salt, urea and water. In the present invention, the calcium salt preferably comprises one or more of calcium acetate, calcium chloride and calcium sulfate, and more preferably calcium acetate. In the present invention, the calcium salt is preferably a regenerated calcium salt, and the regenerated calcium salt is preferably derived from a calcium raw material, and the calcium raw material preferably comprises one or more of eggshells, shells and oyster shells.

[0046] In the present invention, when the regenerated calcium salt is preferably regenerated calcium acetate, the regenerated calcium acetate is preferably used in the form of a regenerated calcium acetate dispersion, and the preparation method of the regenerated calcium acetate dispersion preferably comprises the following steps:

[0047] The calcium raw material is crushed to obtain a calcium raw material powder; the calcium raw material powder is mixed with an acetic acid solution and reacted to obtain the regenerated calcium acetate dispersion. In the present invention, the particle size of the calcium raw material powder is preferably 0.5 to 2 mm. In the present invention, the concentration of the acetic acid solution is preferably 13 to 14 mol / L. In the present invention, the solid-liquid ratio of the calcium raw material powder and the acetic acid solution is preferably 1:4 g / mL. In the present invention, the temperature of the reaction is preferably 20 to 30°C, and the time is preferably 2 min; the reaction is preferably carried out under ultrasonic conditions, and the power of the ultrasonic wave is preferably 100 W.

[0048] In the present invention, when the regenerated calcium salt is preferably regenerated calcium chloride, the regenerated calcium chloride is preferably used in the form of a regenerated calcium chloride solution, and the preparation method of the regenerated calcium chloride solution preferably comprises the following steps:

[0049] The calcium raw material is crushed to obtain a calcium raw material powder; the calcium raw material powder and the first hydrochloric acid are mixed, and the reaction is carried out under the condition of adding the second hydrochloric acid dropwise to obtain the regenerated calcium chloride solution. In the present invention, the particle size of the calcium raw material powder is preferably 0.5-2 mm. In the present invention, the concentration of the first hydrochloric acid is preferably 0.1 mol / L. In the present invention, the solid-liquid ratio of the calcium raw material powder and the first hydrochloric acid is preferably 1:1 g / mL. In the present invention, the second hydrochloric acid is preferably dilute hydrochloric acid, and the present invention does not specifically limit the concentration and dosage of the dilute hydrochloric acid, as long as the calcium in the calcium raw material powder can be fully leached. After the reaction, the present invention preferably also includes filtering, adjusting the pH value of the obtained filtrate to 6.5-7.0, and obtaining the regenerated calcium chloride solution.

[0050] In the present invention, when the regenerated calcium salt is preferably regenerated calcium sulfate, the preparation method of the regenerated calcium sulfate preferably comprises the following steps:

[0051] The calcium raw material is crushed to obtain a calcium raw material powder; the calcium raw material powder and the third hydrochloric acid are mixed, a first reaction is carried out, and a clear solution is obtained by filtering; sodium hydroxide and sulfuric acid are added to the clear solution in sequence, and a second reaction is carried out to obtain the regenerated calcium sulfate. In the present invention, the particle size of the calcium raw material powder is preferably 0.5-2 mm. In the present invention, the concentration of the third hydrochloric acid is preferably 3 mol / L. In the present invention, the solid-liquid ratio of the calcium raw material powder and the third hydrochloric acid is preferably 1:4 g / mL. In the present invention, the temperature of the first reaction is preferably room temperature, and the present invention does not specifically limit the time of the first reaction, as long as the system no longer produces bubbles. In the present invention, the ratio of the amount of substance of the sodium hydroxide and the third hydrochloric acid is preferably 1:1; the sodium hydroxide is preferably used in the form of a sodium hydroxide solution, and the concentration of the sodium hydroxide solution is preferably 2.23 mol / L. In the present invention, the concentration of the sulfuric acid is preferably 3.5 mol / L, and the present invention does not specifically limit the amount of the sulfuric acid, as long as the calcium ions can be completely converted into calcium sulfate. In the present invention, the temperature of the second reaction is preferably 45.6°C. The present invention does not specifically limit the time of the second reaction, as long as the calcium ions and sulfate ions can be completely combined. After the second reaction, the present invention preferably further comprises evaporating and concentrating the obtained reaction solution, cooling and crystallizing, filtering and drying to obtain regenerated calcium sulfate.

[0052] In the present invention, the molar ratio of the calcium salt to urea is preferably 1: 1. In the present invention, the concentration of the calcium salt in the binder is preferably 0.25 to 1 mol, specifically 0.25 mol, 0.5 mol, 0.75 mol or 1 mol.

[0053] The present invention does not specifically limit the preparation method of the binder solution, and a mixture preparation method well known to those skilled in the art may be used.

[0054] In the present invention, the volume ratio of the first component to the second component is 1:1.

[0055] The present invention also provides a method for improving sandy soil, comprising the following steps:

[0056] Spraying the second component and the first component sequentially onto the surface of the sand to improve the sand;

[0057] The first component and the second component are the first component and the second component in the sand conditioner described in the above technical solution.

[0058] In the present invention, the second component is preferably sprayed 3 to 5 times, specifically 3, 4 or 5 times; the volume ratio of the second component sprayed each time to the volume of sand is preferably 1:6.25 to 1:15, more preferably 1:10; after each spraying of the second component, it is preferably allowed to stand for 20 to 40 minutes, more preferably 30 minutes.

[0059] In the present invention, the number of spraying of the first component is preferably 3 to 12 times, specifically 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 times; the volume ratio of the first component sprayed each time to the volume of sand is preferably 1:6.25 to 1:15, more preferably 1:10; after each spraying of the first component, it is preferably also allowed to stand for 12 to 48 hours, more preferably 36 hours.

[0060] In the present invention, the functional bacteria can mineralize the calcium salt in the cementing liquid and the free calcium ions in the sand into inorganic cementing calcium carbonate, which is consolidated on the surface of the sand to form a crust. This crust has good covering ability and low albedo, and can reduce the rate of increase of the surface temperature of the sand. During the same irradiation time, the surface temperature of the sand is low, thereby reducing the evaporation of water in the sand during the day, enhancing the water holding capacity of the sand and slowing down the evaporation capacity. The inorganic cement formed by the functional bacteria has higher strength and physical and chemical indicators than the inorganic cement formed by chemical cementation.

[0061] The sand improver and the sand improving method provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0062] Example 1

[0063] A sand conditioner comprises a first component and a second component.

[0064] Wherein, the first component is a functional bacterial suspension, and the preparation method of the functional bacterial suspension comprises the following steps:

[0065] a. The functional bacteria in the form of a slant were transferred and activated to obtain a bacterial solution containing activated bacteria, which was the second generation of Bacillus pasteurianus with an OD600 value of 1.136.

[0066] b. Prepare the culture medium at room temperature. The specific composition is 5.0 g of peptone, 3.0 g of beef extract, 20.0 g of urea, and 1.0 L of distilled water.

[0067] c. The bacterial solution containing the activated bacteria obtained in step a was inoculated into the culture medium obtained in step b at a volume ratio of 1:100, and cultured on a shaker at 20-30°C and 180 rpm for 24 h to obtain a culture solution, and the OD600 value was measured to be 1.534.

[0068] d. Centrifuge the culture at 2000 rpm for 20 min, discard the supernatant, retain the bacteria at the bottom, and dilute the bacteria to obtain a concentration of 9.8×10 8 CFU / mL of functional bacterial suspension.

[0069] The second component is a binder, wherein the binder includes regenerated calcium acetate, urea and water.

[0070] The preparation method of the cementing liquid comprises the following steps:

[0071] e. Preparation of regenerated calcium acetate dispersion: the collected eggshells are washed, dried, and crushed into powder with a particle size of 0.5 to 2 mm; the powdered eggshells are mixed with acetic acid solution (concentration of 14 mol / L) at a solid-to-liquid ratio of 1:4 g / mL, and then ultrasonic treatment time is 2 min at 30° C. and 100 W of power to obtain a regenerated calcium acetate dispersion.

[0072] f. Preparation of the cementing liquid: using regenerated calcium acetate dispersion, urea and water as raw materials, prepare a cementing liquid with a regenerated calcium acetate concentration of 1 mol / L and a urea concentration of 1 mol / L.

[0073] g. Spray the binder obtained in step f on the surface of the sand three times. The ratio of the volume of the binder sprayed each time to the volume of the sand is 1:10. After each spraying, let it stand for 30 minutes.

[0074] h. Continue to spray the functional bacteria suspension obtained in step d on the surface of the sand for three times. The ratio of the volume of the functional bacteria suspension sprayed each time to the volume of the sand is 1:10. After each spraying, let it stand for 24 hours to improve the sand.

[0075] The volume ratio of the binder liquid and the functional bacteria suspension sprayed each time is 1:1.

[0076] Example 2

[0077] A sand conditioner comprises a first component and a second component.

[0078] Wherein, the first component is a functional bacterial suspension, and the preparation method of the functional bacterial suspension comprises the following steps:

[0079] a. The functional bacteria in the form of a slant were transferred and activated to obtain a bacterial solution containing activated bacteria, which was the second generation of Bacillus pasteurianus with an OD600 value of 1.156.

[0080] b. Prepare the culture medium at room temperature. The specific composition is 5.0 g of peptone, 3.0 g of beef extract, 20.0 g of urea, and 1.0 L of distilled water.

[0081] c. The bacterial solution containing the activated bacteria obtained in step a was inoculated into the culture medium obtained in step b at a volume ratio of 1:100, and cultured on a shaker at a constant temperature of 20-30°C and 180 rpm for 24 h to obtain a culture solution. The OD600 value was measured to be 1.234.

[0082] d. Centrifuge the culture at 10,000 rpm for 10 min, discard the supernatant, retain the bacteria at the bottom, and dilute the bacteria to a concentration of 7.4 × 10 8 CFU / mL of functional bacterial suspension.

[0083] The second component is a binder fluid, wherein the binder fluid comprises regenerated calcium chloride, urea and water.

[0084] The preparation method of the cementing liquid comprises the following steps:

[0085] e. Preparation of regenerated calcium chloride solution: the collected kitchen waste eggshells and oyster shells are cleaned, dried and crushed into small pieces, the small pieces of eggshells and oyster shells are mixed with 0.1 mol / L hydrochloric acid solution at a solid-liquid ratio of 1:1 g / mL, and then dilute hydrochloric acid is gradually added to allow the two to react fully, the feed liquid after the reaction is completed is filtered, and then the pH value of the obtained filtrate is adjusted to 6.5-7.0 to obtain a regenerated calcium chloride solution.

[0086] f. Preparation of the cementing fluid: using regenerated calcium chloride solution, urea and water as raw materials, a cementing fluid with a regenerated calcium chloride concentration of 0.75 mol / L and a urea concentration of 0.75 mol / L was prepared.

[0087] g. Spray the binder obtained in step f on the surface of the sand three times. The ratio of the volume of the binder sprayed each time to the volume of the sand is 1:10. After each spraying, let it stand for 30 minutes.

[0088] h. Continue to spray the functional bacteria suspension obtained in step d on the surface of the sand for three times. The ratio of the volume of the functional bacteria suspension sprayed each time to the volume of the sand is 1:10. After each spraying, let it stand for 24 hours to improve the sand.

[0089] Among them, the total volume ratio of the binder liquid and the functional bacteria suspension sprayed each time is 1:1.

[0090] Comparative Example 1

[0091] The difference from Example 1 is that the rotation speed of the centrifugal treatment in step d is 0 rpm, and the rest is the same as Example 1.

[0092] Comparative Example 2

[0093] The difference from Example 1 is that the rotation speed of the centrifugal treatment in step d is 16000 rpm, and the rest is the same as Example 1.

[0094] Example 3

[0095] The difference from Example 1 is that step e is not performed, and commercially available calcium acetate is directly used as a raw material to prepare the binder liquid. The rest is the same as Example 1.

[0096] Example 4

[0097] The difference from Example 1 is that Bacillus pasteurianus is replaced by Bacillus lentus, and the rest is the same as Example 1.

[0098] Example 5

[0099] A sand conditioner comprises a first component and a second component, wherein the first component is a functional bacteria suspension, and a preparation method of the functional bacteria suspension comprises the following steps:

[0100] a. The functional bacteria in the form of a slant were transferred and activated to obtain a bacterial solution containing activated bacteria, which was the third generation of Bacillus pasteurianus with an OD600 value of 0.938.

[0101] b. Prepare the culture medium at room temperature. The specific composition is 5.0 g of peptone, 3.0 g of beef extract, 20.0 g of urea, and 1.0 L of distilled water.

[0102] c. The bacterial solution containing the activated bacteria obtained in a was inoculated into the culture medium obtained in b at a volume ratio of 1:100, and cultured on a shaker at 20-30°C and 180 rpm for 24 h to obtain a culture solution. The OD600 value was measured and found to be 1.204.

[0103] d. Centrifuge the culture at 10,000 rpm for 10 min, discard the supernatant, retain the bacteria at the bottom, and dilute the bacteria to a concentration of 7.7 × 10 8 CFU / mL of functional bacterial suspension.

[0104] The second component is a binder fluid, wherein the binder fluid comprises regenerated calcium sulfate, urea and water.

[0105] The preparation method of the cementing liquid comprises the following steps:

[0106] e. Preparation of regenerated calcium sulfate: wash eggshells with clean water, grind them into powder, add 3 mol / L dilute hydrochloric acid solution, react at room temperature, filter after the reaction to obtain a clear solution, add sodium hydroxide solution (the concentration of sodium hydroxide solution is 2.23 mol / L) in an amount equal to that of the dilute hydrochloric acid solution to the clear solution, finally react with 3.5 mol / L sulfuric acid at a reaction temperature of 45.6°C, evaporate and concentrate the reaction solution, and then cool and crystallize, filter and dry the obtained viscous material in turn to obtain regenerated calcium sulfate.

[0107] f. Preparation of cementing fluid: Use regenerated calcium sulfate, urea and water as raw materials to obtain a cementing fluid with the concentration of regenerated calcium sulfate and urea being 1 mol / L respectively.

[0108] g. Spray the binder obtained in step f on the surface of the sand three times. The ratio of the volume of the binder sprayed each time to the volume of the sand is 1:10. After each spraying, let it stand for 30 minutes.

[0109] h. Continue to spray the functional bacteria suspension obtained in step d on the surface of the sand for three times. The ratio of the volume of the functional bacteria suspension sprayed each time to the volume of the sand is 1:10. After each spraying, let it stand for 24 hours.

[0110] The volume ratio of the binder liquid and the functional bacteria suspension sprayed each time is 1:1.

[0111] Figure 1 The temperature rise rate curve of the sand surface layer under natural light radiation after using the modifiers of the embodiment and the comparative example is shown in FIG. Figure 1 It can be seen that: the temperature of the sand treated by centrifugation is lower than that of the sand not treated by centrifugation, the temperature of the sand improved with a high OD value is lower than that of the sand with a low OD value, the temperature of the sand improved with Bacillus pasteurianus is lower than that of the sand improved with Bacillus lentus, and the temperature of the sand improved with calcium acetate treated in step e as raw material is equivalent to the temperature of the sand improved with calcium acetate purchased commercially.

[0112] Figure 2 The temperature rise rate of sand at different depths under natural light radiation changes, where the blue line is natural sand, the orange line is sand treated in Example 1, and the green line is sand treated in Example 2; Figure 2 It can be seen that the temperature of the sand sprayed with the sand conditioner of Example 1 and Example 2 at different soil depths is significantly lower than that of the natural sand.

[0113] Figure 3 This is the infrared spectrum of sand under natural light radiation. The darker the color, the lower the temperature. Figure 3 It can be seen that the sand conditioner with regenerated calcium acetate as the calcium source has a better effect on cooling and reducing evaporation of sand.

[0114] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A sand conditioner, characterized in that: comprising a first component and a second component; The first component is a functional bacteria suspension, wherein the functional bacteria include one or more of Bacillus pasteurianus, Sporosarcina pasteurianus and Bacillus lentus, and the concentration of the functional bacteria suspension is 10 6 ~10 9 CFU / mL; The second component is a cementing liquid, which includes calcium salt, urea and water; The volume ratio of the first component to the second component is 1:

1.

2. The sand conditioner according to claim 1, characterized in that: The preparation method of the functional bacteria suspension comprises the following steps: The activated bacterial strains are inoculated into a culture medium for cultivation to obtain the functional bacterial suspension.

3. The sand conditioner according to claim 2, characterized in that: The culture medium includes the following concentration components: Peptone 4.5-5.5g / L, beef extract 2.5-3.5g / L, urea 18-22g / L, and the balance is distilled water.

4. The sand conditioner according to claim 2 or 3, characterized in that: The culture temperature is 20-30° C., and the culture time is 12-36 hours. The culture is carried out on a shaker, and the rotation speed of the shaker is 150-200 rpm.

5. The sand conditioner according to claim 2, characterized in that: After the culture, the system is centrifuged to discard the colored liquid on the upper layer and retain the bacteria on the bottom; the bacteria are diluted to obtain the functional bacteria suspension; the rotation speed of the centrifugation is 2000-10000 rpm and the time is 5-25 minutes.

6. The sand conditioner according to claim 1, characterized in that: The calcium salt includes one or more of calcium acetate, calcium chloride and calcium sulfate; the amount ratio of the calcium salt to urea is 1:1; In the binder, the concentration of calcium salt is 0.25-1 mol / L.

7. The sand conditioner according to claim 1 or 6, characterized in that: The calcium salt is a regenerated calcium salt, which is derived from a calcium raw material, and the calcium raw material includes one or more of eggshells, shells and oyster shells.

8. A method for improving sandy soil, characterized in that: The following steps are involved: Spraying the second component and the first component sequentially onto the surface of the sand to improve the sand; The first component and the second component are the first component and the second component in the sand conditioner according to any one of claims 1 to 7.

9. The improved method according to claim 8, characterized in that: The second component is sprayed 3 to 5 times, and the volume ratio of the second component sprayed each time to the volume of sand is 1:6.25 to 1:15; after each spraying of the second component, it is also required to stand for 20 to 40 minutes.

10. The consolidation method according to claim 8, characterized in that: The first component is sprayed 3 to 12 times, and the volume ratio of the first component sprayed each time to the volume of the sand is 1:6.25 to 1:15; after each spraying of the first component, it is also left to stand for 12 to 48 hours.

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