Method for efficient activation of mixed-structure attapulgite and application of the mixed-structure attapulgite in saline-alkali soil improver

Abstract

The application discloses a kind of mixed-dimension attapulgite efficient activation methods, it includes the following steps: (1) the moisture content of mixed-dimension attapulgite is adjusted to 20~30wt%, extrusion is made into sheet;(2) after uniform spraying phosphoric acid to the surface of sheet, aging, calcination;(3) the sheet after calcination is crushed, and the obtained powder is mixed with 3-amino-N-(carboxyl carbonyl) alanine sufficiently, to obtain activated mixed-dimension attapulgite.Compared with prior art, the alkalization degree and salt content of saline-alkali soil can be significantly reduced after mixed-dimension attapulgite is activated by the method of the application.

Description

Technical Field

[0001] This invention belongs to the field of attapulgite, specifically relating to a highly efficient activation method for mixed-fiber attapulgite. Background Technology

[0002] Lacustrine sedimentary mixed-dimensional attapulgite clay has enormous reserves in Gansu Province, accounting for over 70% of the national total. It is primarily composed of one-dimensional attapulgite (its content may not exceed 50%), accompanied by two-dimensional clay minerals such as illite, chlorite, kaolinite, and illite-montmorillonite mixed-layer clay, as well as quartz, carbonates, and sulfates. It is considered a low-grade mineral, making its high-value application difficult. To address this issue, this invention aims to actively explore the practical application potential of mixed-dimensional attapulgite in improving saline-alkali land through efficient activation. Summary of the Invention

[0003] To achieve the above objectives, this invention provides a method for the efficient activation of mixed-fiber attapulgite.

[0004] A highly efficient activation method for mixed-fiber attapulgite includes the following steps:

[0005] (1) Adjust the moisture content of the mixed attapulgite to 20~30wt% and extrude it into thin sheets;

[0006] (2) After uniformly spraying phosphoric acid onto the surface of the thin film, it is aged and calcined;

[0007] (3) The calcined sheet is crushed and then the powder is thoroughly mixed with 3-[(carboxylcarbonyl)amino]-L-alanine to obtain activated mixed attapulgite.

[0008] Preferably, in step (1), a three-roll mill is used for extrusion, and the extrusion is performed 5 to 10 times.

[0009] More preferably, the roller spacing is 0.5~1 mm, the roller pressure is 5~8 MPa, and the rotation speed is 10~15 r / min.

[0010] Preferably, in step (2), the concentration of phosphoric acid is 30 wt%, and the spraying amount is 15-20 wt% of the sheet mass.

[0011] Preferably, in step (2), the aging time is 20~24h.

[0012] Preferably, in step (2), the calcination temperature is 350~400℃ and the time is 1~2h.

[0013] Preferably, in step (3), the amount of 3-[(carboxycarbonyl)amino]-L-alanine is 2-5% of the powder mass.

[0014] Preferably, in step (3), the mixing temperature is 60~70℃ and the time is 1~2h.

[0015] The activated mixed-fiber attapulgite obtained by the above method.

[0016] A saline-alkali soil conditioner, by weight, comprises: 50-60 parts of activated mixed attapulgite as described above, 15-20 parts of humic acid, 10-25 parts of calcium lactate, 5-10 parts of salt-absorbing microbial agent, 3-5 parts of Franklinella, 8-20 parts of amino acid fermentation tail liquid, and 15-20 parts of nitrogen, phosphorus, and potassium compound fertilizer. Detailed Implementation

[0017] The technical solution of the present invention will be further described in detail below with reference to the embodiments.

[0018] Example 1

[0019] 1. Place the mixed attapulgite powder (purchased from Baiyin Fengbao Agricultural Chemical Technology Co., Ltd., attapulgite content 14.3%) in a constant temperature and humidity chamber and equilibrate for 4 hours at 25℃ and 60% relative humidity. Then adjust the moisture content to 20~30 wt% by spray humidification, stir evenly, seal and let stand for 12 hours to ensure uniform moisture penetration.

[0020] 2. The mixed attapulgite powder, after moisture adjustment, is continuously fed into the feed inlet of a three-roll mill (Changzhou Zili Intelligent Equipment Co., Ltd., model SYL150-300, roller material: wear-resistant alloy steel, roller diameter 300 mm, roller spacing 0.5~1 mm, roller pressure 5~8MPa, speed 10~15r / min) for repeated extrusion. The extrusion is repeated 5~10 times. The thickness of the sheet is checked after every 2 extrusions to ensure uniformity of sheet thickness (deviation ≤±0.1mm). The formed sheets are then collected.

[0021] 3. Use a high-pressure sprayer (atomized particle size 50~100 μm) to evenly spray 30wt% phosphoric acid onto the surface of the sheet. The spraying amount is 15~20% of the sheet mass. During the spraying process, continuously and gently turn the sheet to avoid local liquid accumulation.

[0022] 4. Transfer the phosphoric acid-sprayed flakes to a sealed aging chamber and age them for 24 hours at 20-25°C and 60-70% relative humidity.

[0023] 5. After aging, spread the thin slices flat on a ceramic tray (layer thickness ≤ 2cm), put them into a muffle furnace, heat them to 350℃ at a rate of 5℃ / min, keep them at that temperature for 2 hours, and then let them cool naturally to room temperature after calcination.

[0024] 6. Crush the cooled flakes and pass them through a 100-mesh standard sieve (specific surface area not less than 150 m²). 2 / g).

[0025] 7. Place the sieved powder in a high-speed mixer and add 3-[(carboxycarbonyl)amino]-L-alanine (purchased from Maclean's Reagent Company, CAS: 5302-45-4, pre-dissolved in distilled water to prepare a 10wt% solution) at 2-5% of the powder weight. Set the mixing temperature to 60-70℃, the speed to 300-400r / min, and the time to 1-1.5h.

[0026] 8. Dry the material at 80℃ until the moisture content is ≤5%, pulverize it through a 100-mesh sieve to obtain activated mixed attapulgite (cation exchange capacity ≥25mmol / 100g).

[0027] Preparation of Saline-Alkali Soil Improvement Agent

[0028] The raw material proportions, by weight, are as follows:

[0029] 50 parts activated mixed attapulgite, 15 parts humic acid, 10 parts calcium lactate, 5 parts salt-alkali absorbing microbial agent (purchased from Denong Ecological Agriculture Technology Co., Ltd.), 3 parts Franklinella (purchased from Shanghai Xige Biotechnology Co., Ltd.), 8 parts amino acid fermentation tail liquid (purchased from Baiyin Fengbao Agricultural Chemical Technology Co., Ltd.), and 15 parts nitrogen, phosphorus and potassium compound fertilizer (purchased from Baiyin Fengbao Agricultural Chemical Technology Co., Ltd.).

[0030] First, add the modified and activated mixed attapulgite, humic acid, calcium lactate, and NPK compound fertilizer into a double-helix conical mixer, set the speed to 30-50 r / min, and mix for 20-30 min. Then, adjust the temperature inside the mixer to 25-30℃ and the relative humidity to ≤40%, add the salt-alkali absorbing microbial agent, Frankincense, and amino acid fermentation tail liquid, and continue mixing for 5-8 min to obtain the saline-alkali soil conditioner.

[0031] Comparative Example 1

[0032] The preparation of activated mixed-fiber attapulgite is the same as in Example 1, except that steps 7-8 are omitted.

[0033] Preparation of Saline-Alkali Soil Improvement Agent

[0034] The raw material proportions, by weight, are as follows:

[0035] 50 parts activated mixed attapulgite, 15 parts humic acid, 10 parts calcium lactate, 5 parts salt-alkali absorbing microbial agent, 3 parts Frankincense, 8 parts amino acid fermentation tail liquid, and 15 parts nitrogen, phosphorus and potassium compound fertilizer.

[0036] First, add the modified and activated mixed attapulgite, humic acid, calcium lactate, and NPK compound fertilizer into a double-helix conical mixer, set the speed to 30-50 r / min, and mix for 20-30 min. Then, adjust the temperature inside the mixer to 25-30℃ and the relative humidity to ≤40%, add the salt-alkali absorbing microbial agent, Frankincense, and amino acid fermentation tail liquid, and continue mixing for 5-8 min to obtain the saline-alkali soil conditioner.

[0037] Comparative Example 2

[0038] 1. Place the mixed attapulgite powder in a constant temperature and humidity chamber and equilibrate for 4 hours at 25℃ and 60% relative humidity. Then adjust the moisture content to 20~30 wt% by spray humidification, stir evenly, seal and let stand for 12 hours to ensure uniform moisture penetration.

[0039] 2. Use a high-pressure sprayer (atomized particle size 50~100 μm) to uniformly spray 30wt% phosphoric acid onto the powder surface. The spraying amount is 15~20% of the powder mass. The powder is continuously stirred during the spraying process.

[0040] 3. Transfer the powdered material after spraying with phosphoric acid to a sealed aging chamber and age it for 24 hours at 20~25℃ and 60%~70% relative humidity.

[0041] 4. After aging, spread the material evenly on a ceramic tray (layer thickness ≤ 2cm), place it in a muffle furnace, heat it to 350℃ at a rate of 5℃ / min, hold it at that temperature for 2 hours, and then let it cool naturally to room temperature after calcination.

[0042] 5. After cooling, crush and pass through a 100-mesh standard sieve.

[0043] 6. Place the sieved powder in a high-speed mixer and add 3-[(carboxycarbonyl)amino]-L-alanine (pre-dissolved in distilled water to prepare a 10wt% solution) at 2-5% of the powder weight. Set the mixing temperature to 60-70℃, the speed to 300-400r / min, and the time to 1-1.5h.

[0044] 7. Dry the material at 80℃ until the moisture content is ≤5%, then crush it through a 100-mesh sieve to obtain activated mixed attapulgite.

[0045] Preparation of Saline-Alkali Soil Improvement Agent

[0046] The raw material proportions, by weight, are as follows:

[0047] 50 parts activated mixed attapulgite, 15 parts humic acid, 10 parts calcium lactate, 5 parts salt-alkali absorbing microbial agent, 3 parts Frankincense, 8 parts amino acid fermentation tail liquid, and 15 parts nitrogen, phosphorus and potassium compound fertilizer.

[0048] First, add the modified and activated mixed attapulgite, humic acid, calcium lactate, and NPK compound fertilizer into a double-helix conical mixer, set the speed to 30-50 r / min, and mix for 20-30 min. Then, adjust the temperature inside the mixer to 25-30℃ and the relative humidity to ≤40%, add the salt-alkali absorbing microbial agent, Frankincense, and amino acid fermentation tail liquid, and continue mixing for 5-8 min to obtain the saline-alkali soil conditioner.

[0049] Application Experiment

[0050] 1. Saline-alkali land improvement experiment

[0051] The saline-alkali soil conditioner was thoroughly mixed with the tested saline-alkali soil at a ratio of 1:99 (by mass), and the mixture was then placed into an acrylic glass soil column (115 mm inner diameter, 300 mm height) and compacted. An indoor static leaching test of the soil column was used to explore the desalination effect of deionized water leaching and its role in improving the soil's physical and chemical properties. Each group included three replicate experiments, with leaching performed every 12 hours for a total duration of 5 days. Specific results are shown in Table 1.

[0052] 2. Experiment with potted bok choy

[0053] The saline-alkali soil conditioner was thoroughly mixed with the tested saline-alkali soil at a ratio of 1:99 (by mass) and filled into flower pots. Then, Chinese cabbage seeds were sown evenly. In an artificial climate chamber, the light duration was controlled to 12 hours per day, the temperature was set to 25 degrees Celsius, and the relative humidity was adjusted to 60% to create consistent environmental conditions. Water was applied regularly and in measured amounts to maintain stable soil moisture. Each treatment was replicated three times. The specific results are shown in Table 1.

[0054] Table 1. Improvement effects of different saline-alkali land conditioners

[0055]

[0056] The only difference between the saline-alkali land conditioner in Comparative Example 3 in Table 1 and Example 1 is that it does not contain Frankincense.

[0057] Soil pH was determined according to NY / T 1377-2007, soil alkalinity was calculated according to LY / T 1249-1999, and soil salinity was tested according to NY / T 1121.16-2006.

[0058] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for efficient activation of mixed-fiber attapulgite, comprising the following steps: (1) Adjust the moisture content of the mixed attapulgite to 20~30wt% and extrude it into thin sheets; (2) After uniformly spraying phosphoric acid onto the surface of the thin film, it is aged and calcined; (3) The calcined sheet is crushed and then the powder is thoroughly mixed with 3-[(carboxylcarbonyl)amino]-L-alanine to obtain activated mixed attapulgite.

2. The method according to claim 1, characterized in that: In step (1), a three-roll mill is used for extrusion, and the extrusion is performed 5 to 10 times.

3. The method according to claim 2, characterized in that: The roller spacing is 0.5~1 mm, the roller pressure is 5~8 MPa, and the rotation speed is 10~15 r / min.

4. The method according to claim 1, characterized in that: In step (2), the concentration of phosphoric acid is 30 wt%, and the spraying amount is 15-20 wt% of the sheet mass.

5. The method according to claim 1, characterized in that: In step (2), the aging time is 20~24h.

6. The method according to claim 1, characterized in that: In step (2), the calcination temperature is 350~400℃ and the time is 1~2h.

7. The method according to claim 1, characterized in that: In step (3), the amount of 3-[(carboxycarbonyl)amino]-L-alanine used is 2-5% of the powder mass.

8. The method according to claim 1, characterized in that: In step (3), the mixing temperature is 60~70℃ and the time is 1~2h.

9. An activated mixed-fiber attapulgite obtained by the method according to any one of claims 1-8.

10. A saline-alkali land conditioner, comprising, by weight: The active mixed attapulgite as described in claim 9 consists of 50-60 parts, humic acid 15-20 parts, calcium lactate 10-25 parts, salt-alkali absorbing microbial agent 5-10 parts, Frankella asiatica 3-5 parts, amino acid fermentation tail liquid 8-20 parts, and nitrogen-phosphorus-potassium compound fertilizer 15-20 parts.

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