Microencapsulated high-alkalinity adjuvants and their use in the production of high-alkalinity worm cast manure

Abstract

The application discloses a kind of microencapsulated high alkalinity adjuvant and its application in high alkalinity worm manure preparation, raw materials include high alkalinity adjuvant, sodium alginate, Tris-HCl solution and calcium chloride solution;Among them, the weight ratio of high alkalinity adjuvant, sodium alginate, Tris-HCl solution and calcium chloride solution is 1:1~3:40~150:150~200;The microencapsulated high alkalinity adjuvant is prepared by scientific and reasonable process steps, and the microencapsulated high alkalinity adjuvant is introduced into worm compost, the adverse effects on the life activities of earthworms are reduced, and the high alkalinity worm manure with stable pH and excellent fertilizer efficiency is prepared to meet the needs of acidic soil environment for fertilizer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fertilizer preparation, in particular to a microencapsulated high-alkalinity auxiliary material and its application in the preparation of high-alkalinity vermicompost. BACKGROUND

[0002] Vermicompost is a kind of fine granular material discharged by mixing soil in the process of adding livestock and poultry manure, straw and other organic waste in the vermicomposting bed, and using the life activities of earthworms to utilize and transform these organic matters. Vermicompost contains a high content of organic matter, and also contains a large amount of plant essential elements and trace elements, which can provide sufficient and easily available nutrients for plant growth. In addition, there are many large and small aggregate structures in vermicompost, which can make the soil loose and easy to cultivate, and improve the soil aeration and water and fertilizer retention capacity. Therefore, vermicompost as a kind of high-quality organic fertilizer has been widely used in agricultural production. In the process of transforming waste into organic matter by earthworms, various microbial activities will discharge acidic substances, so that the pH of the vermicompost tends to be neutral, in order to provide a soil environment conducive to plant growth. However, for acid soil, the yield-increasing effect of the slightly neutral vermicompost after application is not significant. Therefore, the preparation of high-alkalinity vermicompost is the key to improving the application effect of vermicompost in acid soil.

[0003] Alkaline tailings are derived from tailings produced in the mineral processing of metal mines (such as lead-zinc mines, copper mines, etc.), as well as waste produced by some chemical industries (such as calcium carbide production, chlor-alkali industry, etc.). Due to the presence of a large amount of alkaline substances such as hydroxides, carbonates, silicates, etc., alkaline tailings usually have high pH values and fine particle sizes. For example, calcium carbide slag, with an average particle size of 40-60 μm, mainly contains calcium hydroxide, and has a pH value of 12-14. Steel slag after fine crushing usually has a particle size of 30-45 μm, and mainly contains calcium oxide, magnesium oxide, silicon dioxide, etc., and has a pH value of 11-13. A total of 1.7 billion tons of alkaline tailings by-products are produced worldwide each year. If not properly disposed of, they will cause a series of environmental problems, such as soil alkalization, affecting plant growth, and alkaline wastewater seeping into the ground or flowing into surface water bodies, which will change the chemical properties of the water body and cause damage to aquatic ecosystems. If these alkaline tailings can be applied to the vermicomposting process, it will help to increase the pH of the vermicompost and prepare high-alkalinity vermicompost. However, due to the adverse effects of these high-alkalinity materials on the life activities of earthworms, there is currently no technology to combine the two for development and utilization. SUMMARY

[0004] The microencapsulated high-alkalinity auxiliary material is prepared through scientific and reasonable process steps, and the microencapsulated high-alkalinity auxiliary material is introduced into earthworm compost, so that the adverse effects of the earthworm compost on the life activities of earthworms are reduced, and the high-alkalinity earthworm compost with stable pH and excellent fertilizer efficiency is prepared to meet the demand of an acid soil environment for fertilizers.

[0005] To achieve the above-mentioned purpose, the technical scheme designed by the present application is as follows:

[0006] The present application provides a kind of microencapsulated high-alkalinity auxiliary material, and its raw materials include high-alkalinity auxiliary material, sodium alginate, Tris-HCl solution and calcium chloride solution;Wherein, the weight ratio of high-alkalinity auxiliary material, sodium alginate, Tris-HCl solution and calcium chloride solution is 1:1~3:40~150: 150~200;

[0007] The raw material of the high-alkalinity auxiliary material is composed of alkaline tailings, quicklime and potassium hydroxide solution, and the weight ratio is 1:1~2:1~2;And the concentration of Tris-HCl solution is 40~60mmoL / L;

[0008] The mass fraction of calcium chloride solution is 2~4%;The concentration range of potassium hydroxide solution is 0.5~1.0mol / L.

[0009] Further, the high-alkalinity auxiliary material, sodium alginate, Tris-HCl solution and calcium chloride solution;Wherein, the weight ratio of high-alkalinity auxiliary material, sodium alginate, Tris-HCl solution and calcium chloride solution is 1:1~2:40~100: 150~200;

[0010] The weight ratio of alkaline tailings, quicklime and potassium hydroxide solution is 1:1~1.5: 1~1.5;

[0011] And the concentration of Tris-HCl solution is 45~55mmoL / L;

[0012] The mass fraction of calcium chloride solution is 2~3%。

[0013] The concentration range of potassium hydroxide solution is 0.5~1.0mol / L.

[0014] Further, the high-alkalinity auxiliary material, sodium alginate, Tris-HCl solution and calcium chloride solution;Wherein, the weight ratio of high-alkalinity auxiliary material, sodium alginate, Tris-HCl solution and calcium chloride solution is 1:1~2:40~100: 150~200;

[0015] The weight ratio of the alkaline tailings, quicklime and potassium hydroxide solution is 1:1-1.5:1-1.5;

[0016] And the concentration of Tris-HCl solution is 50 mmoL / L.

[0017] The mass fraction of calcium chloride solution is 2.5%.

[0018] The above-mentioned alkaline tailings are selected from lead tailings, iron tailings, copper tailings and tungsten tailings.

[0019] The application also provides a preparation method of the above-mentioned microencapsulated high-alkalinity auxiliary material, comprising the following steps:

[0020] 1) The alkaline tailings, quicklime and potassium hydroxide solution are weighed according to the above-mentioned weight ratio;

[0021] 2) The alkaline tailings are ball-milled and crushed, then the ball-milled particles of the alkaline tailings are mixed with the quicklime, and the potassium hydroxide solution is added and stirred uniformly to obtain a mixed slurry;

[0022] 3) The mixed slurry is placed in a high-pressure digestion tank for hydrothermal reaction, and after completion, the product is taken out, filtered, dried and ball-milled to obtain a high-alkalinity auxiliary material;

[0023] 4) The high-alkalinity auxiliary material, sodium alginate, Tris-HCl solution and calcium chloride solution are weighed according to the above-mentioned weight ratio;

[0024] 5) The sodium alginate is added to the Tris-HCl solution for the first time to stir and mix uniformly, and a first mixed solution containing sodium alginate is obtained, and the mass fraction of sodium alginate in the first mixed solution is 2.0-2.5%;

[0025] 6) The high-alkalinity auxiliary material is added to the first mixed solution for the second time to stir and mix uniformly to obtain a second mixed solution;

[0026] 7) The second mixed solution of the high-alkalinity auxiliary material-sodium alginate is dropped into the calcium chloride solution for microencapsulation treatment of the high-alkalinity auxiliary material, and is hardened after standing, and the microcapsules are collected, washed and obtained to obtain a microencapsulated high-alkalinity auxiliary material.

[0027] Further, in the step 2), the particle size of the ball-milled particles of the alkaline tailings is ≤100 μm.

[0028] Further, the particle size of the high-alkalinity auxiliary material is ≤100 μm.

[0029] Further, in the step 5), the first stirring condition is:

[0030] The stirring temperature is 30°C, the stirring speed is 300 r / min, and the stirring time is 1 h.

[0031] The second stirring condition is:

[0032] The stirring temperature is 30 DEG C, the stirring speed is 250 r / min, and the stirring time is 1 h.

[0033] Further, in the step 6), the temperature for the hardening by standing is 20 DEG C, and the time is 30 min.

[0034] The microencapsulated high-alkalinity auxiliary material has a particle size of 450-550 mu m.

[0035] The application further provides a preparation method of the high-alkalinity worm manure.

[0036] a. preparing worm compost raw materials by mixing cow dung and crushed straw and carrying out aerobic fermentation, wherein,

[0037] b. mixing the microencapsulated high-alkalinity auxiliary material into the worm compost raw materials, inoculating the earthworms (Eisenia foetida), Eisenia fetida controlling the environmental temperature and humidity, and carrying out worm composting (the worm composting mode is one-time feeding-whole harvesting, and the whole worm composting process needs to be completed within 30 days); wherein the amount of the microencapsulated high-alkalinity auxiliary material mixed into the worm compost raw materials is 25-35%;

[0038] c. separating the earthworms in time after the worm composting is completed, collecting the earthworm manure, and obtaining the high-alkalinity worm manure.

[0039] Further, in the step a, the pH value of the worm compost raw materials is 6.5-7.5, the carbon-nitrogen ratio (C / N) is 20-30:1, and the water content is 60%-70%.

[0040] In the step b, the inoculation amount of the earthworms is 15-30 g of earthworms per kg of worm compost raw materials.

[0041] The worm compost raw materials are prepared as follows:

[0042] a. airing fresh cow dung for 1-2 days, and crushing corn straw, wheat straw or rice straw to 1-3 centimeters at the same time;

[0043] b. uniformly mixing the cow dung and the straw according to the weight percentage ratio of 60%-70%:30%-40%, adjusting the water content to 60%-65%, and stacking for 15-20 days until the color of the raw materials becomes dark brown, there is no obvious odor, and the straw fibers are soft and fragile.

[0044] The application has the following beneficial effects:

[0045] 1. Compared with traditional vermicomposting technology, the application introduces alkaline tailings into the vermicomposting process while ensuring the activity of earthworms and the efficiency of vermicomposting by microencapsulating the auxiliary materials and controlling the vermicomposting conditions, thereby realizing the resource utilization of alkaline tailings.

[0046] 2. Compared with traditional vermicompost, the product prepared by the application has high alkalinity, and can effectively neutralize hydrogen ions in the soil after application in acidic soil, thereby playing the role of precise acid reduction and long-acting acid inhibition and improving the beneficial effect in acidic soil.

[0047] 3. Compared with alkaline tailings, the application uses the earthworm's over-ventral action to couple minerals and organic matter, thereby obtaining an acidic soil improvement product with fertilization function, which can quickly improve the acidic environment of the soil after application, restore soil structure and nutrient availability, and alleviate the problems of soil compaction and plant toxicity caused by the separate application of alkaline tailings.

[0048] 4. The high-alkalinity vermicompost prepared by the application has the dual functions of acid reduction and fertilization, and the high contents of active silicon, calcium and potassium elements can better address the problem of the loss of silicon, calcium and potassium elements in acidic soil, and can significantly improve crop yield and quality when applied in acidic soil.

[0049] 5. The preparation method of the application is simple, stable and suitable for large-scale industrial production, which can provide a large amount of high-alkalinity vermicompost for agricultural production. DETAILED DESCRIPTION

[0050] The application will be further described in detail below with reference to specific examples for the understanding of those skilled in the art.

[0051] Example 1

[0052] The preparation method of the microencapsulated high-alkalinity auxiliary material 1 comprises the following steps:

[0053] 1) Weigh lead tailings, quicklime and potassium hydroxide solution according to the weight ratio of 1:1:2; wherein the concentration of the potassium hydroxide solution is 0.5 mol / L;

[0054] 2) Ball mill the lead tailings, then mix the lead tailings particles with a particle size of ≤100 μm with quicklime, and then add the potassium hydroxide solution and stir uniformly to obtain a mixed slurry;

[0055] 3) Put the mixed slurry into a high-pressure digestion tank for hydrothermal reaction, take out the product after completion, filter, dry and ball mill to obtain high-alkalinity auxiliary materials with a particle size of ≤100 μm;

[0056] 4) high alkalinity auxiliary materials, sodium alginate, Tris-HCl solution and calcium chloride solution are weighed according to the weight ratio of 1:1.5:70:200; wherein the concentration of Tris-HCl solution is 50 mmoL / L, and the mass fraction of calcium chloride solution is 2.5%;

[0057] 5) sodium alginate is added to the Tris-HCl solution, and the first mixed solution containing sodium alginate is obtained by stirring at a temperature of 30 DEG C and a speed of 300 r / min for 1 h; the mass fraction of sodium alginate in the first mixed solution is 2.2%;

[0058] 6) high alkalinity auxiliary materials are added to the first mixed solution, and the second mixed solution is obtained by stirring at a temperature of 30 DEG C and a speed of 250 r / min for 1 h;

[0059] 7) the second mixed solution of high alkalinity auxiliary materials-sodium alginate is dropped into the calcium chloride solution to perform microencapsulation treatment on the high alkalinity auxiliary materials, and the microencapsulated high alkalinity auxiliary material 1 with a particle size of 450-550 mu m is obtained by hardening at a temperature of 20 DEG C for 30 min, collecting and washing the microcapsules.

[0060] Example 2

[0061] The preparation method of the microencapsulated high alkalinity auxiliary material 2 comprises the following steps:

[0062] 1) lead tailings, quicklime and potassium hydroxide solution are weighed according to the weight ratio of 1:1.5:2; wherein the concentration of potassium hydroxide solution is 0.5 mol / L;

[0063] 2) the lead tailings are ball milled and crushed, then the lead tailing particles with a particle size of less than or equal to 100 mu m are mixed with the quicklime, and the mixture slurry is obtained by adding and stirring the potassium hydroxide solution;

[0064] 3) the mixture slurry is placed in a high-pressure digestion tank for hydrothermal reaction, and the product is taken out after completion, filtered, dried and ball milled to obtain high alkalinity auxiliary materials with a particle size of less than or equal to 100 mu m;

[0065] 4) high alkalinity auxiliary materials, sodium alginate, Tris-HCl solution and calcium chloride solution are weighed according to the weight ratio of 1:1.5:70:200; wherein the concentration of Tris-HCl solution is 50 mmoL / L, and the mass fraction of calcium chloride solution is 2.5%;

[0066] 5) sodium alginate is added to the Tris-HCl solution, and the first mixed solution containing sodium alginate is obtained by stirring at a temperature of 30 DEG C and a speed of 300 r / min for 1 h; the mass fraction of sodium alginate in the first mixed solution is 2.2%;

[0067] 6) The high alkalinity auxiliary material is added to the first mixed solution, and stirred for 1 h at 30°C and 250 r / min to obtain a second mixed solution;

[0068] 7) The second mixed solution of the high alkalinity auxiliary material-sodium alginate is dropped into the calcium chloride solution for microencapsulation treatment of the high alkalinity auxiliary material, and the microcapsules are collected and washed after being hardened at 20°C for 30 min, to obtain microencapsulated high alkalinity auxiliary material 2 with a particle size of 450-550 μm.

[0069] Example 3

[0070] The preparation method of the microencapsulated high alkalinity auxiliary material 3 comprises the following steps:

[0071] 1) Lead tailings, quicklime and potassium hydroxide solution are weighed according to a weight ratio of 1:1.5:2; wherein the concentration of the potassium hydroxide solution is 1.0 mol / L;

[0072] 2) The lead tailings are ball milled and crushed, then the lead tailing particles with a particle size of ≤100 μm are mixed with the quicklime, and the potassium hydroxide solution is added and stirred uniformly to obtain a mixed slurry;

[0073] 3) The mixed slurry is placed in a high-pressure digestion tank for hydrothermal reaction, and the product is taken out after completion, filtered, dried and ball milled to obtain high alkalinity auxiliary material with a particle size of ≤100 μm;

[0074] 4) The high alkalinity auxiliary material, sodium alginate, Tris-HCl solution and calcium chloride solution are weighed according to the above weight ratio of 1:1.5:70:200; wherein the concentration of the Tris-HCl solution is 50 mmoL / L, and the mass fraction of the calcium chloride solution is 2.5%;

[0075] 5) The sodium alginate is added to the Tris-HCl solution, and stirred for 1 h at 30°C and 300 r / min to obtain a first mixed solution containing sodium alginate, and the mass fraction of the sodium alginate in the first mixed solution is 2.2%;

[0076] 6) The high alkalinity auxiliary material is added to the first mixed solution, and stirred for 1 h at 30°C and 250 r / min to obtain a second mixed solution;

[0077] 7) The second mixed solution of the high alkalinity auxiliary material-sodium alginate is dropped into the calcium chloride solution for microencapsulation treatment of the high alkalinity auxiliary material, and the microcapsules are collected and washed after being hardened at 20°C for 30 min, to obtain microencapsulated high alkalinity auxiliary material 3 with a particle size of 450-550 μm.

[0078] Example 4

[0079] The preparation method of the microencapsulated high-alkalinity adjuvant 4 comprises the following steps:

[0080] 1) Take lead tailings, quicklime and potassium hydroxide solution according to the weight ratio of 1:1.5:2; wherein the concentration of the potassium hydroxide solution is 1.0 mol / L;

[0081] 2) Ball mill the lead tailings, then mix the lead tailings particles with a particle size of ≤100 μm with the quicklime, and then add the potassium hydroxide solution to stir uniformly to obtain a mixed slurry;

[0082] 3) Put the mixed slurry into a high-pressure digestion tank for hydrothermal reaction, take out the product after completion, filter, dry and ball mill to obtain high-alkalinity adjuvants with a particle size of ≤100 μm;

[0083] 4) Take the high-alkalinity adjuvant, sodium alginate, Tris-HCl solution and calcium chloride solution according to the weight ratio of 1:1.5:60:200; wherein the concentration of the Tris-HCl solution is 50 mmoL / L, and the mass fraction of the calcium chloride solution is 2.5%;

[0084] 5) Add the sodium alginate to the Tris-HCl solution to stir for 1 h at a temperature of 30°C and a rotation speed of 300 r / min to mix uniformly to obtain a first mixed solution containing sodium alginate, and the mass fraction of the sodium alginate in the first mixed solution is 2.5%;

[0085] 6) Add the high-alkalinity adjuvant to the first mixed solution to stir for 1 h at a temperature of 30°C and a rotation speed of 250 r / min to mix uniformly to obtain a second mixed solution;

[0086] 7) Drop the second mixed solution of the high-alkalinity adjuvant-sodium alginate into the calcium chloride solution to perform microencapsulation treatment on the high-alkalinity adjuvant, and then place it at a temperature of 20°C for 30 min to harden, collect the microcapsules, wash and obtain microencapsulated high-alkalinity adjuvant 4 with a particle size of 450 μm-550 μm.

[0087] Comparative Example 1

[0088] The preparation method of the microencapsulated high-alkalinity adjuvant D1 comprises the following steps:

[0089] 1) Take lead tailings, quicklime and potassium hydroxide solution according to the weight ratio of 1:3:2; wherein the concentration of the potassium hydroxide solution is 0.5 mol / L;

[0090] 2) Ball mill the lead tailings, then mix the lead tailings particles with a particle size of ≤100 μm with the quicklime, and then add the potassium hydroxide solution to stir uniformly to obtain a mixed slurry;

[0091] 3) Put the mixed slurry into a high-pressure digestion tank for hydrothermal reaction, and after completion, take out the product, filter, dry, and ball mill to obtain high-alkalinity auxiliary materials with a particle size of ≤100 μm;

[0092] 4) High-alkalinity auxiliary materials, sodium alginate, Tris-HCl solution, and calcium chloride solution are weighed according to the above weight ratio of 1:1.5:70:200; wherein the concentration of the Tris-HCl solution is 50 mmoL / L, and the mass fraction of the calcium chloride solution is 2.5%;

[0093] 5) The sodium alginate is added to the Tris-HCl solution and stirred at a temperature of 30°C and a speed of 300 r / min for 1 h for the first time to mix uniformly; a first mixed solution containing sodium alginate is obtained, and the mass fraction of sodium alginate in the first mixed solution is 2.2%;

[0094] 6) The high-alkalinity auxiliary materials are added to the first mixed solution and stirred at a temperature of 30°C and a speed of 250 r / min for 1 h for the second time to mix uniformly, and a second mixed solution is obtained;

[0095] 7) The second mixed solution of the high-alkalinity auxiliary materials-sodium alginate is dropped into the calcium chloride solution for microencapsulation treatment of the high-alkalinity auxiliary materials, and the microcapsules are collected after being hardened at a temperature of 20°C for 30 min, washed, and obtained as microencapsulated high-alkalinity auxiliary materials D1 with a particle size of 450 μm-550 μm.

[0096] Comparative Example 2

[0097] The preparation method of the microencapsulated high-alkalinity auxiliary materials D2 comprises the following steps:

[0098] 1) Lead tailings, quicklime, and potassium hydroxide solution are weighed according to the weight ratio of 1:1:2; wherein the concentration of the potassium hydroxide solution is 2.5 mol / L;

[0099] 2) The lead tailings are ball milled and crushed, then the lead tailing particles with a particle size of ≤100 μm are mixed with the quicklime, and the potassium hydroxide solution is added and stirred uniformly to obtain a mixed slurry;

[0100] 3) The mixed slurry is put into a high-pressure digestion tank for hydrothermal reaction, and after completion, the product is taken out, filtered, dried, and ball milled to obtain high-alkalinity auxiliary materials with a particle size of ≤100 μm;

[0101] 4) High-alkalinity auxiliary materials, sodium alginate, Tris-HCl solution, and calcium chloride solution are weighed according to the above weight ratio of 1:1.5:70:200; wherein the concentration of the Tris-HCl solution is 50 mmoL / L, and the mass fraction of the calcium chloride solution is 2.5%;

[0102] 5) The sodium alginate is added to the Tris-HCl solution and stirred for 1 h at 30°C and 300 r / min for the first time to obtain a first mixed solution containing sodium alginate, and the mass fraction of sodium alginate in the first mixed solution is 2.2%;

[0103] 6) The high-alkalinity auxiliary material is added to the first mixed solution and stirred for 1 h at 30°C and 250 r / min for the second time to obtain a second mixed solution;

[0104] 7) The second mixed solution of the high-alkalinity auxiliary material-sodium alginate is dropped into the calcium chloride solution to perform microencapsulation treatment on the high-alkalinity auxiliary material, and the microcapsules are collected after being hardened at 20°C for 30 min, washed, and obtained as the microencapsulated high-alkalinity auxiliary material D2 with a particle size of 450-550 μm.

[0105] Comparative Example 3

[0106] The preparation method of the microencapsulated high-alkalinity auxiliary material D3 comprises the following steps:

[0107] 1) The lead tailings, quicklime, and potassium hydroxide solution are weighed according to the weight ratio of 1:1:2; wherein the concentration of the potassium hydroxide solution is 0.5 mol / L;

[0108] 2) The lead tailings are ball milled and crushed, then the lead tailings particles with a particle size of ≤100 μm are mixed with the quicklime, and the potassium hydroxide solution is added and stirred uniformly to obtain a mixed slurry;

[0109] 3) The mixed slurry is placed in a high-pressure digestion tank for hydrothermal reaction, and the product is taken out after completion, filtered, dried, and ball milled to obtain high-alkalinity auxiliary material with a particle size of ≤100 μm;

[0110] 4) The high-alkalinity auxiliary material, sodium alginate, Tris-HCl solution, and calcium chloride solution are weighed according to the weight ratio of 1:1.5:30:200; wherein the concentration of the Tris-HCl solution is 50 mmoL / L, and the mass fraction of the calcium chloride solution is 2.5%;

[0111] 5) The sodium alginate is added to the Tris-HCl solution and stirred for 1 h at 30°C and 300 r / min for the first time to obtain a first mixed solution containing sodium alginate, and the mass fraction of sodium alginate in the first mixed solution is 2.2%;

[0112] 6) The high-alkalinity auxiliary material is added to the first mixed solution and stirred for 1 h at 30°C and 250 r / min for the second time to obtain a second mixed solution;

[0113] 7) The second mixed solution of the above high-alkalinity adjuvant-sodium alginate is dripped into the calcium chloride solution to microencapsulate the high-alkalinity adjuvant, which is hardened at 20°C for 30 min, and the microcapsules are collected and washed to obtain the microencapsulated high-alkalinity adjuvant D3 with a particle size of 400-600 pm.

[0114] Comparative Example 4

[0115] The preparation method of the microencapsulated high-alkalinity adjuvant D4 includes the following steps:

[0116] 1) The lead tailings, quicklime and potassium hydroxide solution are weighed according to the weight ratio of 1:1:2; wherein the concentration of the potassium hydroxide solution is 0.5 mol / L;

[0117] 2) The lead tailings are ball-milled and crushed, then the lead tailings particles with a particle size of ≤100 pm are mixed with the quicklime, and the potassium hydroxide solution is added and stirred uniformly to obtain a mixed slurry;

[0118] 3) The mixed slurry is placed in a high-pressure digestion tank for hydrothermal reaction, and after completion, the product is taken out, filtered, dried and ball-milled to obtain a high-alkalinity adjuvant with a particle size of ≤100 pm;

[0119] 4) The high-alkalinity adjuvant, sodium alginate, Tris-HCl solution and calcium chloride solution are weighed according to the weight ratio of 1:4:180:200; wherein the concentration of the Tris-HCl solution is 50 mmoL / L, and the mass fraction of the calcium chloride solution is 2.5%;

[0120] 5) The sodium alginate is added to the Tris-HCl solution and stirred at a temperature of 30°C and a speed of 300 r / min for 1 h to mix uniformly; a first mixed solution containing sodium alginate is obtained, and the mass fraction of the sodium alginate in the first mixed solution is 2.2%;

[0121] 6) The high-alkalinity adjuvant is added to the first mixed solution and stirred at a temperature of 30°C and a speed of 250 r / min for 1 h to mix uniformly, and a second mixed solution is obtained;

[0122] 7) The second mixed solution of the above high-alkalinity adjuvant-sodium alginate is dripped into the calcium chloride solution to microencapsulate the high-alkalinity adjuvant, which is hardened at 20°C for 30 min, and the microcapsules are collected and washed to obtain the microencapsulated high-alkalinity adjuvant D4 with a particle size of 400-600 pm.

[0123] Comparative Example 5

[0124] The preparation method of the high-alkalinity adjuvant D5 includes the following steps:

[0125] 1) Weigh lead tailings, quicklime and potassium hydroxide solution by weight ratio 1:1:2; wherein the concentration of potassium hydroxide solution is 0.5 mol / L;

[0126] 2) Ball mill the lead tailings, then mix the lead tailings particles with particle size ≤100 μm with quicklime, and then add potassium hydroxide solution to stir uniformly to obtain a mixed slurry;

[0127] 3) Put the mixed slurry into a high-pressure digestion tank for hydrothermal reaction, and after completion, take out the product, filter, dry and ball mill to obtain high-alkalinity auxiliary material D5 with particle size ≤100 μm.

[0128] The pH, active SiO2, active K2O and active CaO contents of the microencapsulated high-alkalinity auxiliary materials in the preparation process of Examples 1-4 and Comparative Examples 1-5 are determined, the average particle size, particle size range and breakage rate of the microencapsulated high-alkalinity auxiliary materials are determined, the earthworm biomass change after obtaining the earthworm manure is determined, and the pH, organic matter content, total nutrient content and seed germination rate of the earthworm manure are determined. The results are as follows:

[0129] Table 1 Comparison of pH, active SiO2, active K2O and active CaO contents of different microencapsulated high-alkalinity auxiliary materials

[0130]

[0131] The concentration of hydrogen ions in acidic soil is relatively high, and hydrogen ions will exchange with calcium, potassium and other cations adsorbed on the soil colloid, and the exchanged calcium, potassium and other cations will be lost with soil water movement under the condition of rainfall, etc. In addition, a large amount of aluminum ions and iron ions exist in acidic soil, which will compete with silicon ions for adsorption sites on the surface of soil colloid, and silicon ions have weak adsorption ability and are easily exchanged into soil solution and lost. Therefore, increasing the contents of active SiO2, K2O and CaO in the auxiliary material is extremely important for supplementing the lost calcium, potassium and silicon ions in acidic soil. Table 1 shows that although the pH of the high-alkalinity auxiliary materials obtained by the control example and the examples are all above 11, the active SiO2 content of the high-alkalinity auxiliary materials obtained by Examples 1-4 is all greater than 26%, the active K2O content is all greater than 0.74%, and the active CaO content is all greater than 14.5%, which are stable in nature and can effectively supplement the lost calcium, potassium and silicon ions in acidic soil. On the contrary, due to the improper ratio of tailings to quicklime or the improper concentration of KOH solution in Comparative Example 1 and Comparative Example 2, the contents of active SiO2, K2O and CaO are all significantly lower than those of the examples, which shows that their effects on supplementing calcium, potassium and silicon ions in acidic soil are weak.

[0132] Table 2 Average particle size, particle size range and breakage rate of microencapsulated high-alkalinity auxiliary materials

[0133]

[0134] The purpose of microencapsulation is to reduce the stimulation of high-alkalinity excipients on earthworm gut, so that earthworms can eat smoothly. Therefore, the average particle size and particle size uniformity of microencapsulated high-alkalinity excipients determine whether they can be mixed with earthworm compost raw materials to reduce the possibility of selective feeding by earthworms. The breakage rate of microencapsulated high-alkalinity excipients affects the stability of the properties of the excipients during the entire earthworm composting process. In Table 2, Comparative Example 5 did not perform microencapsulation of high-alkalinity excipients, so there is no data. Except for Comparative Example 5, the average particle size of microencapsulated high-alkalinity excipients obtained from all comparative examples and examples is between 495-510 µm, but Comparative Examples 3 and 4 have a particle size difference of 100 µm due to improper sodium alginate concentration or high-alkalinity excipient: sodium alginate input ratio, which is significantly higher than that of the examples (the difference is less than 40 µm). In addition, the microcapsule breakage rate of Comparative Examples 3 and 4 reaches more than 20%, while the breakage rate of Examples 1-4 is less than 12%.

[0135] According to the results in Table 1 and Table 2, the microencapsulated high-alkalinity excipient preparation method (Examples 1-4) in the present application improves the content of active SiO2, K2O and CaO by alkali activation, and obtains uniform microcapsule size and low microcapsule breakage rate. In contrast, the content of active SiO2, K2O and CaO in Comparative Examples 1-2 is significantly lower than that in Examples, and the microcapsule breakage rate in Comparative Examples 3-4 is significantly higher than that in Examples, which cannot achieve good microencapsulation of high-alkalinity excipients.

[0136] Examples 5-8

[0137] A preparation method of high-alkalinity earthworm manure 1-4, comprising the following steps:

[0138] a. mixing cow dung and crushed straw for aerobic fermentation to prepare earthworm compost raw materials, wherein the pH value of the earthworm compost raw materials is 6.5-7.5, the carbon-nitrogen ratio (C / N) is 20-30:1, and the water content is 60%-70%; the specific steps are as follows:

[0139] ①Fresh cow dung is dried for 1-2 days, and corn straw, wheat straw or rice straw is crushed to 1-3 centimeters at the same time;

[0140] ②Mix the cow dung and the straw according to the weight percentage ratio of 60%-70%:30%-40%, adjust the water content to 60%-65%, and stack for 15-20 days until the color of the raw materials turns to dark brown, there is no obvious odor, and the straw fibers are soft and easily broken.

[0141] b. Mix microencapsulated high-alkalinity excipients 1-4 into the earthworm compost raw materials, respectively, inoculate Eisenia foetida ( Eisenia fetida), control the temperature and humidity of the environment, and carry out vermicomposting (the vermicomposting method is one-time feeding-whole harvesting, and the whole vermicomposting process needs to be completed within 30 days); wherein the amount of the microencapsulated high-alkalinity auxiliary material mixed into the vermicomposting raw material is 30%.

[0142] c. After the vermicomposting is completed, the earthworms are separated in time, the earthworm manure is collected, and the high-alkalinity earthworm manure 1-4 is obtained.

[0143] Example 9

[0144] The preparation method of the high-alkalinity earthworm manure 5 of the present example is basically the same as that of the high-alkalinity earthworm manure 1, except that:

[0145] The amount of the microencapsulated high-alkalinity auxiliary material 1 mixed into the vermicomposting raw material is 35%.

[0146] Comparative Examples 6-9

[0147] The preparation method of the high-alkalinity earthworm manure d1-d4 in Comparative Examples 6-9 is basically the same as that of the high-alkalinity earthworm manure 1, except that:

[0148] The microencapsulated high-alkalinity auxiliary materials d1-d4 are mixed into the vermicomposting raw material, respectively.

[0149] Comparative Example 10

[0150] The preparation method of the high-alkalinity earthworm manure d5 in the present comparative example is basically the same as that of the high-alkalinity earthworm manure 1, except that:

[0151] The microencapsulated high-alkalinity auxiliary material 1 is mixed into the vermicomposting raw material, and the amount of the microencapsulated high-alkalinity auxiliary material 1 mixed into the vermicomposting raw material is 50%.

[0152] Comparative Example 11

[0153] The preparation method of the high-alkalinity earthworm manure d6 in the present comparative example is basically the same as that of the high-alkalinity earthworm manure 1, except that:

[0154] The microencapsulated high-alkalinity auxiliary material 1 is mixed into the vermicomposting raw material, and the amount of the microencapsulated high-alkalinity auxiliary material 1 mixed into the vermicomposting raw material is 10%.

[0155] Comparative Example 12

[0156] The preparation method of the high-alkalinity earthworm manure d7 in the present comparative example is basically the same as that of the high-alkalinity earthworm manure 1, except that:

[0157] The microencapsulated high-alkalinity auxiliary material 1 is mixed into the vermicomposting raw material, and the vermicomposting time is 50 days.

[0158] Comparative Example 13

[0159] The comparative example 8 is prepared by the same method as the preparation method of the high-alkalinity vermicompost 1, except that:

[0160] The microencapsulated high-alkalinity auxiliary material D5 is mixed into the vermicompost raw material.

[0161] Comparative example 14

[0162] The high-alkalinity vermicompost d9 is obtained by directly mixing the microencapsulated high-alkalinity auxiliary material D5 into the material after the earthworms pass through the stomach according to the amount of 10% of the vermicompost raw material.

[0163] Comparative example 15

[0164] The high-alkalinity vermicompost d10 is obtained by directly mixing the microencapsulated high-alkalinity auxiliary material 1 into the material after the earthworms pass through the stomach according to the amount of 300% of the vermicompost raw material.

[0165] Table 3: Changes in earthworm biomass and pH, organic matter content, total nutrient content, and seed germination rate of vermicompost

[0166]

[0167] The purpose of the present application is to introduce alkaline tailings into vermicomposting to prepare high-alkalinity vermicompost. The feeding and excretion behavior of earthworms is the key to vermicomposting, and the change in earthworm biomass is an important indicator of whether the vermicomposting process is proceeding smoothly. Comparative examples 14 and 15 do not involve the vermicomposting process, so there is no corresponding data.

[0168] Table 3 shows that after the end of the vermicomposting process, the earthworm biomass of the examples increased by nearly 1 times compared to before vermicomposting, indicating that the vermicomposting process proceeded smoothly and good earthworm protein output was obtained after the end of the vermicomposting process. In addition, the pH of the vermicompost obtained in the examples is all above 8.5, which is significantly higher than that of traditional vermicompost (usually between 6.5-7.5), indicating that the vermicompost obtained in the examples has certain acid reduction function. The organic matter content of the vermicompost obtained in the examples is all above 36%, the total nutrient content is all above 4.7%, and the seed germination rate is all higher than 74%, meeting the requirements of the corresponding indicators in NY525.

[0169] In comparison, the earthworm biomass of Comparative Examples 10 and 13 is reduced, indicating that the material has an adverse effect on earthworms and causes the death of earthworms, and the earthworm compost fails to start, which is due to: Comparative Example 10 adds a too high amount of microencapsulated high-alkalinity adjuvant, so that the material is not suitable for earthworms to eat; Comparative Example 13 does not microencapsulate the high-alkalinity adjuvant, and the high-alkalinity characteristics of the adjuvant directly lead to the death of earthworms. Comparative Example 12 has a too long earthworm composting time, which leads to an adverse effect of the rupture of the microencapsulated high-alkalinity adjuvant on earthworms in the later period and causes the death of earthworms. The earthworm biomass of Comparative Examples 6, 7, 8 and 9 does not change significantly, indicating that the earthworm composting efficiency is not high, which limits the output of the earthworm product in the earthworm composting, and especially the seed germination index of the earthworm manure obtained in Comparative Examples 8 and 9 does not meet the requirements of NY525. Comparative Example 11 adds too low microencapsulated high-alkalinity adjuvant, although the earthworm composting can proceed smoothly and the organic matter, total nutrients and germination index of the earthworm manure are good, but the pH is only 7.7, which is not consistent with the purpose of preparing high-alkalinity earthworm manure according to the present application. Comparative Example 14 directly mixes the high-alkalinity adjuvant, and the adjuvant directly contacts with the seeds, leading to the germination index not meeting the requirements. Comparative Example 15 obtains a product with properties similar to those of the examples, but it does not go through the earthworm over-vent passage, but is a simple mixing process of traditional earthworm manure and microencapsulated high-alkalinity adjuvant.

[0170] According to the requirement of NY525 that the seed germination index is ≥70%, the earthworm manure products of Comparative Examples 6, 11, 15 and Examples 5-9, as well as traditional earthworm manure and high-alkalinity tailing powder are selected for potting experiments, and CK without any material is set for comparison. The soil is collected from Xianning, Hubei, with a pH value of 4.8, an organic matter content of 12.8 g / kg, and the contents of available nitrogen, available phosphorus and available potassium are 42.1 g / kg, 11.2 mg / kg and 112 mg / kg, respectively. Each material is mixed with the soil at a rate of 10%, and the soil water content is adjusted to 23%. Two seedlings of Shanghai green seedlings with 2-3 true leaves are transplanted, and the pots are placed in a greenhouse for 30 days before harvesting. After the Shanghai green is harvested, two seedlings of Shanghai green seedlings are transplanted again for the second crop planting to verify the long-term acid suppression effect of the product. The relevant indexes of plants and soil are measured when the two crops of Shanghai green are harvested. The results are as follows:

[0171] Table 4 Soil acidity and acid buffer capacity

[0172]

[0173] Table 4 shows that, compared with CK, the high-alkalinity vermicompost prepared in the examples can significantly increase the soil pH, reduce the exchangeable acid content, and enhance the acid-base buffering capacity of the soil in the first crop planting. Moreover, the high-alkalinity vermicompost has a long-acting acid suppression effect, and after the second crop planting, the soil does not show obvious acid return, and the soil pH decreases by no more than 0.5 pH value. In contrast, the high-alkalinity tailing powder directly applied in the first crop planting shows the strongest acid reduction capacity, but its effect is not sustainable, and after the second crop planting, the soil pH decreases by 1.3 pH values. The comparative example 15 performs poorly in long-acting acid suppression compared with the examples, and after the second crop planting, the soil pH decreases by 0.9 pH values. The traditional vermicompost and the vermicompost prepared in comparative example 11 do not show an improvement effect on soil acidity due to their own low pH. Comparative example 6 can maintain the soil pH within a small range of fluctuations, but the acid-base buffering capacity of the soil under its application is significantly lower than that of the examples.

[0174] Table 5 Soil nutrient status

[0175]

[0176] Table 5 shows that, compared with CK, after the application of the high-alkalinity vermicompost prepared in the examples, the soil nutrient content is significantly improved, which is due to the fact that the vermicompost itself contains rich plant-available nutrients, and also related to the fact that the application of the high-alkalinity vermicompost increases the soil pH value and activates the fixed nutrients in the soil. In addition, the high-alkalinity vermicompost prepared in the examples has good sustained nutrient supply capacity, and as the organic matter in the manure continues to mineralize, it continuously supplements the nutrients in the soil for crop absorption and utilization. In contrast, the high-alkalinity tailing powder has little ability to fertilize the soil after application, and its soil nutrient content is similar to that of CK. The traditional vermicompost and the vermicompost prepared in comparative example 11 can supplement part of the soil available nutrients, but due to their failure to significantly improve soil acidity and effectively activate the fixed nutrients in the soil, the soil available phosphorus content is significantly lower than that of the examples. The products prepared in comparative examples 6 and 15 have similar effects on soil nutrients as the examples.

[0177] Table 6 Shanghai green plant height, leaf number and biomass

[0178]

[0179] Table 6 shows that, compared with CK, the growth of Shanghai green is significantly improved after the application of high alkalinity vermicompost prepared in the examples, and the plant height, leaf number and biomass are significantly higher than those of other treatments in two crops. The promotion effect of high alkalinity vermicompost prepared in the examples on the growth of Shanghai green is sustainable, that is, even if the vermicompost is not applied before the second crop planting, the indicators of Shanghai green do not decrease significantly. In contrast, the vermicompost prepared in Comparative Example 11, the traditional vermicompost and the high alkalinity tailings powder cannot significantly promote the growth of Shanghai green compared with CK. Comparative Example 6 has a significantly lower promotion effect on Shanghai green in two crops than the examples. The vermicompost prepared in Comparative Example 15 has the same effect as the examples in the first crop, but the growth-related indicators of Shanghai green decrease significantly in the second crop, indicating that its effect is not sustainable.

[0180] In summary, the high alkalinity vermicompost prepared in the present application has the triple effects of precise acid reduction, long-acting acid suppression and soil fertilization. Compared with traditional vermicompost and high alkalinity mineral application, the product can significantly promote the growth of crops in acid soil and obtain higher yield. The comparison of comparative examples and examples shows that the preparation of high alkalinity vermicompost in the present application needs to follow the various technical points required by the present application, and any change in any technical point will result in the decline of the effect of the obtained vermicompost in precise acid reduction, long-acting acid suppression or sustainable promotion of crop growth.

[0181] The other parts not described in detail are prior art. Although the above examples have made a detailed description of the present application, it is only a part of the examples of the present application, not all examples, and people can also obtain other examples according to the present examples without creativity, which all belong to the protection scope of the present application.

Claims

1. A microencapsulated high alkalinity adjuvant, characterized in that: It is raw material including high alkalinity auxiliary material, sodium alginate, Tris-HCl solution and calcium chloride solution;Among them, the weight ratio of the high alkalinity auxiliary material, sodium alginate, Tris-HCl solution and calcium chloride solution is 1:1~3:40~150: 150~200; The raw material of the high alkalinity auxiliary material is composed of alkaline tailings, quicklime and potassium hydroxide solution, and the weight ratio is 1:1~2:1~2;And the concentration of Tris-HCl solution is 40~60mmoL / L; The mass fraction of calcium chloride solution is 2~4%;The concentration range of potassium hydroxide solution is 0.5~1.0mol / L; The microcapsule particle size of the microencapsulated high alkalinity auxiliary material is 450μm~550μm; The microcapsule breakage rate of the microencapsulated high alkalinity auxiliary material is less than 12%.

2. The microencapsulated high alkalinity adjuvant according to claim 1, characterized in that: The weight ratio of the high alkalinity auxiliary material, sodium alginate, Tris-HCl solution and calcium chloride solution is 1:1~2:40~100: 150~200; The weight ratio of the alkaline tailings, quicklime and potassium hydroxide solution is 1:1~1.5: 1~1.5; And the concentration of Tris-HCl solution is 45~55mmoL / L; The mass fraction of calcium chloride solution is 2~3%; The concentration range of potassium hydroxide solution is 0.5~1.0mol / L.

3. The microencapsulated high alkalinity adjuvant of claim 1, wherein: The weight ratio of the high alkalinity auxiliary material, sodium alginate, Tris-HCl solution and calcium chloride solution is 1:1~2:40~100: 150~200; The weight ratio of the alkaline tailings, quicklime and potassium hydroxide solution is 1:1~1.5: 1~1.5; And the concentration of Tris-HCl solution is 50mmoL / L, and the mass fraction of calcium chloride solution is 2.5%.

4. A process for the preparation of the microencapsulated high alkalinity adjuvant of claim 1, characterized by: It comprises the following steps: 1) weigh the alkaline tailings, quicklime and potassium hydroxide solution according to the weight ratio; 2) ball mill the alkaline tailings, then mix the ball milled particles with quicklime, and then add potassium hydroxide solution and stir uniformly to obtain a mixed slurry; 3) put the mixed slurry into a high pressure digestion tank for hydrothermal reaction, take out the product after completion, filter, dry and ball mill to obtain the high alkalinity auxiliary material; 4) weigh the high alkalinity auxiliary material, sodium alginate, Tris-HCl solution and calcium chloride solution according to the weight ratio; 5) add sodium alginate to Tris-HCl solution and stir at a temperature of 30℃ and a speed of 300 r / min for 1h; Obtain a first mixed solution containing sodium alginate, and the mass fraction of sodium alginate in the first mixed solution is 2.0~2.5%; 6) add high alkalinity auxiliary material to the first mixed solution and stir at a temperature of 30℃ and a speed of 250 r / min for 1h to obtain a second mixed solution; 7) drop the above high alkalinity auxiliary material-sodium alginate second mixed solution into calcium chloride solution for microencapsulation treatment, and harden at a temperature of 20℃ for 30min, collect the microcapsules, wash and obtain the microencapsulated high alkalinity auxiliary material;The microcapsule particle size of the microencapsulated high alkalinity auxiliary material is 450μm~550μm;The microcapsule breakage rate of the microencapsulated high alkalinity auxiliary material is less than 12%.

5. The method of claim 4, wherein: In the step 2), the particle size of the alkaline tailing ball-milling particles is ≤100 μm.

6. The method of claim 4, wherein: In the step 3), the particle size of the high-alkalinity auxiliary material is ≤100 μm.

7. A method of producing a high-alkalinity worm castings, characterized by: The method comprises the following steps: a. mixing cow dung and crushed straw to prepare earthworm compost raw materials through aerobic fermentation, wherein the straw is corn straw, wheat straw or rice straw; b. mixing the microencapsulated high-alkalinity auxiliary material of claim 1 into the earthworm compost raw materials, inoculating earthworms, controlling the environmental temperature and humidity, and performing earthworm composting; wherein the amount of the microencapsulated high-alkalinity auxiliary material mixed into the earthworm compost raw materials is 25-35%; c. separating the earthworms in time after the earthworm composting is completed, collecting the earthworm manure, and obtaining high-alkalinity earthworm manure.

8. The method of claim 7, wherein: In the step a, the pH value of the earthworm compost raw materials is 6.5-7.5, the carbon-nitrogen ratio is 20-30:1, and the water content is 60%-70%; In the step b, the inoculation amount of the earthworms is 15-30 g of earthworms per kg of earthworm compost raw materials.

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