Preparation method of modified cotton stalk carbon-based urea fertilizer

Abstract

The invention discloses a preparation method of modified cotton stalk charcoal-based urea fertilizer, comprising the following steps: crushing cotton stalks and passing them through a sieve, placing them in a crucible and sealing them, pyrolyzing and isothermally isothermal to obtain cotton stalk biochar; diluting wood vinegar, adding cotton stalk biochar and stirring, allowing cotton stalk charcoal to be fully immersed in wood vinegar, filtering out cotton stalk biochar, and drying in a drying oven to obtain modified charcoal; taking cotton stalk biochar and modified charcoal in different beakers, adding pure water, heating and boiling, filtering, and detecting the pH value of the filtrate; crushing urea particles through a sieve and fully mixing them with the modified charcoal, adding a pregelatinized starch binder and stirring to obtain a fertilizer mixture; adding water to the fertilizer mixture, stirring it fully, pouring it into a pellet feed machine for extrusion molding, and drying the molded fertilizer particles after collection. The charcoal-based urea fertilizer prepared by the present invention can be directly applied to saline-alkali soil, prolonging fertilizer efficiency while increasing soil organic matter content, and can effectively reduce the harm of high pH of charcoal-based fertilizer to soil.

Description

Technical Field

[0001] The invention relates to a preparation method of modified cotton straw charcoal-based urea fertilizer. Background Art

[0002] Biochar has a good nitrogen retention effect, improving soil physical and chemical properties, increasing crop yields, and playing a positive role in soil water and fertility conservation. Furthermore, biochar plays a dominant regulatory role in the interaction between charcoal and fertilizer, improving the soil ecosystem, increasing nutrient retention, and reducing nutrient loss, thereby effectively enhancing the soil's overall fertility capacity, thereby promoting crop nutrient absorption and growth. Studies have shown that the interaction between biochar and chemical fertilizers can significantly increase yield and improve quality, reducing chemical fertilizer application rates while improving fertilizer utilization. However, biochar often has a high pH due to its high concentration of alkaline groups, and improper use can compromise the fertility of saline-alkali soils. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the existing methods and provide a method for preparing a modified cotton straw charcoal-based urea fertilizer. In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0004] A method for preparing modified cotton stalk charcoal-based urea fertilizer, comprising: cotton stalk biochar, urea, wood vinegar, and pregelatinized starch binder, wherein the mass ratio of the above formula is 5:3:5:2; the wood vinegar has a pH of 3.09 and a density of 1.009 g / cm 3 , the organic acid content is 4.18%; comprising the following steps:

[0005] Step 1, biochar preparation: Cotton stalks were crushed and passed through a 40-mesh sieve, placed in a ceramic crucible and sealed with tin foil, and placed in a muffle furnace for pyrolysis at a constant temperature of 350°C for 2 hours to obtain cotton stalk biochar;

[0006] Step 2: Preparation of modified carbon: Dilute the wood vinegar solution, add the cotton stalk biochar, and stir to fully soak the cotton stalk biochar in the wood vinegar solution. After 2 hours, filter out the cotton stalk biochar and dry it in a drying oven at 60°C to obtain the modified carbon. The mass ratio of the diluted wood vinegar solution to the cotton stalk biochar is 30:1.

[0007] Step 3: pH test: Place cotton stalk biochar and modified carbon in different beakers, with the ratio of cotton stalk biochar to modified carbon being 1:1; add pure water, heat to boil, filter, and test the pH of the filtrate;

[0008] Step 4: Weighing and mixing: crush the urea granules through a 40-mesh sieve and mix thoroughly with the modified carbon, add the pregelatinized starch binder and stir evenly; the mass ratio of urea, modified carbon, and pregelatinized starch binder is 5:5:2 to prepare a fertilizer mixture;

[0009] Step 5, fertilizer preparation: add water to the fertilizer mixture, stir thoroughly, pour into a pellet feed machine with a rated power of 4.5Kw and a pore size of 3mm for extrusion molding, collect the molded fertilizer particles and dry them for 6 hours; weigh the dried fertilizer and put it into a 500-mesh nylon mesh bag, add pure water and let it stand for 24 hours, remove the extract and make it into a fixed volume to detect the urea nitrogen concentration in the solution after standing for 1, 2, 3, 4, 5, 6, 11, 16, 21, 26, and 31 days to obtain the nutrient release pattern of the carbon-based fertilizer.

[0010] The present invention has the following advantages:

[0011] The prepared carbon-based urea fertilizer can be directly applied to saline-alkaline soil, which can prolong the fertilizer effect while increasing the soil organic matter content and effectively reduce the damage of high pH of carbon-based fertilizer to the soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is the pH comparison before and after cotton stalk carbon modification;

[0013] Figure 2 It is the urea nitrogen release rate of modified carbon-based fertilizer. DETAILED DESCRIPTION

[0014] To facilitate understanding of the technical means, creative features, objectives, and effects achieved by the present invention, the following examples are provided to provide a detailed description of the present invention. It should be noted that the examples are intended only to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Persons skilled in the art may make non-essential improvements and adjustments based on the present invention.

[0015] Example

[0016] A modified cotton stalk charcoal-based urea fertilizer, the formula includes: cotton stalk biochar, urea, wood vinegar, pregelatinized starch binder, the mass of each component is 50g cotton stalk biochar, 30ml wood vinegar, 50g urea, 20g binder,

[0017] The following steps are involved:

[0018] Step 1, biochar preparation: Grind the cotton stalks and pass them through a 40-mesh sieve, put them into a ceramic crucible and seal it with tin foil, put it into a muffle furnace, set the pyrolysis temperature to 350°C, and keep the temperature constant for 2 hours to obtain cotton stalk biochar.

[0019] Step 2, preparation of modified carbon: prepare wood vinegar with a pH of 3.09, a density of 1.009 g / cm3, and an organic acid content of 4.18%, dilute the wood vinegar 50 times, take 1500 ml of the diluted wood vinegar, add 50 g of cotton stalk biochar and stir to fully soak the cotton stalk charcoal in the wood vinegar, filter out the cotton stalk charcoal after 2 hours, and dry it in a drying oven at 60°C to obtain modified carbon.

[0020] Step 3, pH test: weigh 2.5 g of cotton stalk charcoal and modified charcoal respectively into different beakers, add 50 ml of pure water, heat to boil, filter, and test the pH of the filtrate.

[0021] Step 4: weighing and mixing: After crushing the urea granules through a 40 mesh sieve, weigh 50 g and mix them thoroughly with 50 g of modified carbon, then add 20 g of pregelatinized starch binder and stir evenly.

[0022] Step 5, fertilizer preparation: add 15 ml of water to the fertilizer mixture, stir thoroughly, pour into a pellet feed machine, use a mechanical extrusion pellet feed machine with a rated power of 4.5 kW and an aperture of 3 mm, extrude and shape the fertilizer particles, collect the formed fertilizer particles and dry them in a drying oven at 60°C for 6 hours.

[0023] Urea nitrogen extraction of fertilizer: Weigh 4g of dried fertilizer and put it into a 500-mesh nylon mesh bag, add 80ml of pure water and let it stand. After standing for 24 hours, remove the extract and make it to a fixed volume to detect the urea nitrogen concentration in the solution. The concentration was tested on the 1st, 2nd, 3rd, 4th, 5th, 6th, 11th, 16th, 21st, 26th and 31st day respectively to obtain the nutrient release pattern of carbon-based fertilizer.

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Claims

1. A method for preparing modified cotton stalk carbon-based urea fertilizer, comprising the following steps: Step 1, biochar preparation: crush the cotton stalks, pass them through a sieve, put them into a ceramic crucible and seal it, and place it in a muffle furnace for pyrolysis and constant temperature to obtain cotton stalk biochar; Step 2: Preparation of modified carbon: dilute the wood vinegar, add cotton stalk biochar and stir to fully soak the cotton stalk biochar in the wood vinegar. After 2 hours, filter out the cotton stalk biochar and dry it in a drying oven to obtain modified carbon. Step 3, pH test: Take cotton stalk biochar and modified carbon in different beakers, add pure water, heat and boil, filter, and test the pH of the filtrate; Step 4: Weighing and mixing: crush the urea granules through a sieve and mix them thoroughly with the modified carbon, add the pregelatinized starch binder and stir evenly to prepare a fertilizer mixture; Step 5: Fertilizer preparation: Add water to the fertilizer mixture, stir thoroughly, pour into a pellet feed machine for extrusion molding, collect the molded fertilizer pellets and dry them; The mass ratio of the cotton stalk biochar, urea, wood vinegar, and pregelatinized starch binder is 5:3:5:

2. The wood vinegar has a pH of 3.09 and a density of 1.009 g / cm 3 , the organic acid content is 4.18%; in step 1, the pyrolysis temperature is set to 300-350℃ and the constant temperature is 2h; in step 2, the wood vinegar is diluted 50 times, and the mass ratio of the diluted wood vinegar and cotton stalk biochar in step 2 is 30:1; in step 2, the temperature of the drying oven is set to 60℃; in step 3, the ratio of cotton stalk biochar and modified carbon is 1:1; in step 4, the mass ratio of urea, modified carbon and pregelatinized starch binder is 5:5:

2.

2. The method for preparing a modified cotton stalk carbon-based urea fertilizer according to claim 1, wherein: The rated power of the mechanical extrusion pellet feed machine in step 5 is 4.5Kw, and the aperture is 3mm; the drying temperature of the drying box is 60°C, and the drying time is 6h.

3. The method for preparing a modified cotton stalk carbon-based urea fertilizer according to claim 1, wherein: After obtaining the fertilizer in step 5, 4 g of the dried fertilizer is weighed and placed in a 500-mesh nylon mesh bag, 80 ml of pure water is added, and the mixture is allowed to stand for 24 hours. The extract is removed and the urea nitrogen concentration in the solution is determined to a fixed volume. The concentration is tested on the 1st, 2nd, 3rd, 4th, 5th, 6th, 11th, 16th, 21st, 26th, and 31st days of standing to obtain the nutrient release pattern of the carbon-based fertilizer.

4. The method for preparing a modified cotton stalk carbon-based urea fertilizer according to claim 1, wherein: The sieve is a 40-mesh sieve.

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