Preparation method and application of long-acting phosphate fertilizer

Abstract

The invention relates to a preparation method and application of a long-acting phosphate fertilizer, and the preparation method of the long-acting phosphate fertilizer comprises the following steps: step 1, putting ground phosphate rock into a container, adding an activating agent and an auxiliary agent into the container, uniformly stirring the substances, adding water, and continuously stirring and mixing uniformly; step 2, putting the container filled with the mixed solution in the step 1 into an ultrasonic generation device, and performing ultrasonic activation under the conditions of 300W and 40kHz; and step 3, taking out the substance subjected to ultrasonic activation in the step 2 from the ultrasonic generator, and naturally air-drying or drying to obtain the long-acting phosphate fertilizer. The low-grade ground phosphate rock is used as a raw material, the long-acting phosphate fertilizer is prepared through the ultrasonic-assisted organic activation technology, and the activation effect of the ground phosphate rock can be remarkably improved. The prepared long-acting phosphate fertilizer with moderate effectiveness and lasting fertilizer efficiency can be applied to perennial crops, meanwhile, a low-energy-consumption and pollution-free production process is realized, and the long-acting phosphate fertilizer can be applied to green or organic agriculture.

Description

Technical Field

[0001] The invention belongs to the field of fertilizer manufacturing and relates to a method for preparing a long-acting phosphate fertilizer. Background Art

[0002] With the increasing shortage of global phosphate resources, especially the lack of high-grade phosphate, phosphate fertilizer production faces huge challenges; and due to the limitations of processing technology, the utilization of low-grade phosphate is extremely limited. How to reasonably and efficiently utilize low-grade phosphate is the key to breaking through the limitations of phosphate fertilizer.

[0003] There are many problems with the existing phosphate fertilizer production methods: for example, the mechanical method: directly grinding the phosphate rock, the phosphorus effectiveness is low, and it is difficult to meet the phosphorus demand of crops during the rapid growth period; the acid method: although it can produce high-content, water-soluble phosphate fertilizers, the energy consumption is high and the pollutant emissions are large during the production process, which has an adverse impact on the environment; the thermal method: it also has the problem of high energy consumption, and the production process is complicated; the organic activation method: although there are studies on using organic activators or organic materials to activate phosphate rock powder, due to the limitations of reaction conditions, the activation effect is not ideal (see non-patent documents 1 and 2).

[0004] Therefore, the following technical problems exist in the prior art: the production method of high-concentration phosphate fertilizer has high energy consumption and high pollution, and the fertilizer efficiency does not match the crop growth requirements; although the amount of low-quality phosphate rock powder is large, it is difficult to be effectively utilized due to its low phosphorus content and effectiveness; the existing organic activation method is not ideal.

[0005] In view of this situation, it is urgent to develop a new environmentally friendly method that can use low-grade phosphate rock to prepare long-acting phosphate fertilizer, which is of great significance to the sustainable development of the phosphate fertilizer industry.

[0006] Prior art

[0007] Non-patent literature

[0008] Non-patent literature 1: Feng Zhaobin, Study on soil reaction and plant effectiveness of activated phosphate rock powder[D], Chinese Academy of Agricultural Sciences, 2006.

[0009] Non-patent literature 2: Zheng Xiuxing, Discussion on the development direction and path of green and low-carbon technology in my country's phosphate and compound fertilizer industry [J], Phosphate Fertilizer and Compound Fertilizer, 2023, 38(07): 6-11. Summary of the invention

[0010] In order to solve the above technical problems, the present invention aims to provide an environmentally friendly new method for preparing long-acting phosphate fertilizer using low-grade phosphate rock, namely, a method for preparing long-acting phosphate fertilizer using organic activated phosphate rock powder under ultrasonic conditions.

[0011] A technical solution of the present invention is a method for preparing a long-acting phosphate fertilizer, characterized in that it comprises the following steps: (e.g. Figure 1 Flowchart shown in Figure 1)

[0012] Step 1: Put the phosphate rock powder into a container, add the activator and additives into the container, stir these substances evenly, and then add water to continue stirring and mixing;

[0013] Step 2: placing the container containing the uniformly mixed substance in step 1 in an ultrasonic generator, and performing ultrasonic activation at 300W and 40kHz;

[0014] Step 3: Take out the material after ultrasonic activation in step 2 from the ultrasonic generator, and naturally air-dry or dry it in an oven to obtain a long-acting phosphate fertilizer.

[0015] Wherein, in step 1, the activator is selected from any one of weathered coal, amino acid ionic liquid, industrial alkali lignin, industrial sodium (potassium) lignin sulfonate or fiber viscose sludge, and its added amount is 10-50 parts by mass relative to 100 parts by mass of phosphate rock powder, preferably 30-40 parts by mass; the auxiliary agent is anhydrous sodium sulfite, and its added amount is 10-50 parts by mass relative to 100 parts by mass of phosphate rock powder, preferably 10-30 parts by mass; the water is 10 parts by mass.

[0016] The phosphate rock powder in step 1 contains phosphorus (P2O5)>16%, and is a low-grade phosphate rock powder of 80-100 mesh, because the reaction area is increased by grinding, thereby improving the reaction efficiency. There is no specific limitation on the phosphate rock powder of the present invention, because most industrial production tends to use high-grade phosphate rock powder, and the use of low-grade phosphate rock powder has become an industry problem, and the characteristics of the present invention are mainly developed for the use of low-grade phosphate rock powder.

[0017] In step 2, the ultrasonic activation is performed for 1 to 5 hours, preferably 1 to 3 hours.

[0018] The invention improves the water solubility of the activator by adding an auxiliary agent and utilizes ultrasonic wave-assisted organic activation technology to significantly improve the activation effect of phosphate rock powder.

[0019] Technical principle

[0020] Phosphorus in phosphate rock mainly exists in the form of calcium phosphate, which has low effectiveness to plants. The activator contains multiple functional groups, but its water solubility is poor; by adding anhydrous sodium sulfite, a sulfonation reaction occurs, thereby improving its water solubility. In addition, the sulfonated activator can react with the calcium ions in calcium phosphate through chelation to form a chelate, thereby converting the ionic bond between the phosphate and calcium ions into a covalent bond, reducing the bond energy and enhancing the activity of the phosphate; the phosphate reacts with the functional groups of the activator to form an organic phosphorus compound, thereby improving its mobility in the soil and its effectiveness to plants.

[0021] However, under normal mild conditions, the reaction rate is low and the phosphorus activation effect is poor. High temperature, high pressure, strong acid and other conditions can promote the reaction, but the energy consumption and equipment requirements are high, or waste may be generated. In this regard, the present invention utilizes the cavitation effect of ultrasound to generate tiny bubbles, and the bubble collapses to generate local high temperature and high pressure, and releases huge energy, accelerates the collision and energy state of the reactants, promotes the contact reaction of the activator, sodium sulfite and phosphate rock powder, and significantly improves the activation effect. At the same time, ultrasonic technology consumes less energy, the reaction conditions are mild, and no waste is generated, and the production process is green, efficient and pollution-free.

[0022] In addition, the long-acting phosphate fertilizer prepared by the present invention can be applied to all soil types and crops. Since the phosphorus release of the long-acting phosphate fertilizer matches the phosphorus demand of perennial crops well, it is more suitable for perennial crops; it can also be used in green or organic agriculture.

[0023] The present invention has the following beneficial effects:

[0024] The present invention prepares long-acting phosphate fertilizer by ultrasonic-assisted organic activation technology, which can significantly improve the activation effect of phosphate rock powder, so that long-acting phosphate fertilizer with moderate phosphorus effectiveness and long-lasting fertilizer effect can be prepared, and a low-energy consumption and pollution-free production process can be achieved.

[0025] 1. The activation effect is significantly improved: the use of additives and ultrasonic assisted organic activation greatly improves the activation effect of phosphate rock powder, and the effectiveness of phosphorus is moderate.

[0026] 2. Long-lasting fertilizer effect: The prepared long-acting phosphate fertilizer has a long-lasting effect and can meet the phosphorus needs of perennial crops.

[0027] 3. Environmentally friendly: The production process is low-energy and pollution-free, in line with the concept of green chemistry.

[0028] 4. Make rational use of low-grade phosphate rock powder, efficiently and rationally integrate and utilize resources, and reduce economic costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flow chart of the preparation method of the long-acting phosphate fertilizer of the present invention

[0030] Figure 2 The cumulative amount of phosphorus extracted from phosphate fertilizers prepared with different types of activators for eight consecutive times

[0031] Figure 3 The amount of phosphorus extracted from phosphate fertilizers prepared with different amounts of activator for eight consecutive leachings

[0032] Figure 4 The amount of phosphorus extracted from phosphate fertilizers prepared with different amounts of additives after eight consecutive leachings

[0033] Figure 5 The amount of phosphorus extracted from phosphate fertilizers prepared with different activation times after eight consecutive leachings

[0034] Figure 6 The change of water-soluble phosphorus in soil after the long-acting phosphate fertilizer of the present invention is applied to the soil

[0035] Figure 7 The change of soil available phosphorus after the long-acting phosphate fertilizer of the present invention is applied to the soil DETAILED DESCRIPTION

[0036] The technical scheme and effects of the present invention are further described below through specific examples. Parts herein refer to parts by mass.

[0037] Example 1

[0038] according to Figure 1 The process flow chart shown in the figure is to prepare the long-acting phosphate fertilizer of the present invention, and the steps are as follows:

[0039] Step 1: Put 100 parts of phosphate rock powder into a container, add 10 parts of activator A and 10 parts of auxiliary agent into the container, stir these substances evenly, and then add 10 parts of water and continue to stir and mix evenly;

[0040] Step 2: placing the container containing the mixed solution in step 1 in an ultrasonic generator, and performing ultrasonic activation at 300W and 40kHz for 1 hour;

[0041] Step 3: Take out the material after ultrasonic activation in step 2 from the ultrasonic generator, and naturally air-dry or dry it in an oven to obtain a long-acting phosphate fertilizer.

[0042] Embodiments 2 to 25

[0043] Except that the type and amount of the activator, the amount of the auxiliary agent, or the activation time are different from those in Example 1, the other steps are the same as those in Example 1 to prepare the long-acting phosphate fertilizer of the present invention. Orthogonal experimental design is adopted here to obtain phosphate fertilizers prepared by different types, amounts, auxiliary agent amounts and activation times of activators, and the specific data are shown in Table 1. In Table 1, PR is phosphate rock powder, which is used as a control; activator A is industrial sodium lignin sulfonate, activator B is industrial alkali lignin, activator C is fiber viscose sludge, activator D is amino acid ionic liquid, activator E is weathered coal; and the auxiliary agent is anhydrous sodium sulfite.

[0044] Table 1

[0045] Example Activator Type Activation time (h) Activation dose (%) Amount of additives (%) PR - - - - 1 A 1 10 10 2 A 2 20 20 3 A 3 30 30 4 A 4 40 40 5 A 5 50 50 6 B 1 20 30 7 B 2 30 40 8 B 3 40 50 9 B 4 50 10 10 B 5 10 20 11 C 1 30 50 12 C 2 40 10 13 C 3 50 20 14 C 4 10 30 15 C 5 20 40 16 D 1 40 20 17 D 2 50 30 18 D 3 10 40 19 D 4 20 50 20 D 5 30 10 21 E 1 50 40 22 E 2 10 50 23 E 3 20 10 24 E 4 30 20 25 E 5 40 30

[0046] Continuous Leaching Test of Water-soluble Phosphorus

[0047] A continuous extraction test of water-soluble phosphorus was carried out on the long-acting phosphate fertilizers prepared with different activator types and dosages, adjuvant dosages and activation times.

[0048] Figures 2 to 5 In the figure, the phosphorus amount extracted from the phosphate fertilizer prepared by different activator types, activator dosages, auxiliary agent dosages and activation time after 8 consecutive leachings is shown. Among them, PR is phosphate rock powder; activator A is industrial sodium lignin sulfonate, activator B is industrial alkali lignin, activator C is fiber viscose sludge, activator D is amino acid ionic liquid, activator E is weathered coal; the auxiliary agent is anhydrous sodium sulfite; the cumulative phosphorus amount extracted from phosphate rock powder after 8 consecutive leachings is 27 mg / kg. It can be seen from the above figures that the long-acting phosphate fertilizer prepared by the present invention can extract phosphorus for 8 consecutive times, indicating that the phosphate fertilizer effect of this product is long-term and can slowly release the fertilizer effect. It is a long-acting fertilizer suitable for the growth of annual crops.

[0049] Figure 2 It is the cumulative amount of phosphorus leached out of the phosphate fertilizers prepared with different activators after 8 consecutive times. It can be seen from the figure that the cumulative amount of phosphorus leached out of the phosphate fertilizers prepared with the five activators is between 286 and 766 mg / kg, which is significantly higher than phosphate rock powder (27 mg / kg); if the activation effect is considered, activator E has the best effect, followed by activator B, then activator D, activator A, and the lowest is activator C.

[0050] Figure 3 The amount of phosphorus extracted from phosphate fertilizers prepared with different amounts of activator after eight consecutive leachings. Figure 3It can be seen that when activating 100 parts of phosphate rock powder, the addition amount of various activators is 10 to 50 parts, which can significantly increase the cumulative phosphorus amount leached out of the produced phosphate fertilizer, and the value is 449 to 608 mg / kg; considering the activation effect, the addition amount of the activator is 30 to 50 parts. If both the activation effect and the cost of the activator are taken into account, the preferred addition amount of the activator is 30 to 40 parts.

[0051] Figure 4 The amount of phosphorus extracted from phosphate fertilizers prepared with different amounts of additives after eight consecutive leachings. Figure 4 It can be seen that when activating 100 parts of phosphate rock powder, the addition amount of the auxiliary agent anhydrous sodium sulfate is 10-50 parts, and the cumulative phosphorus amount leached out of the prepared phosphate fertilizer is 436-621 mg / kg, which is significantly higher than the 27 mg / kg of phosphorus amount leached out of phosphate rock powder after 8 consecutive cumulative leaching, especially when the addition amount is 10-30 parts. Therefore, considering the activation effect and the cost of the auxiliary agent, the preferred addition amount of the auxiliary agent is 10-30 parts.

[0052] Figure 5 is the amount of phosphorus extracted from phosphate fertilizers prepared with different activation times after eight consecutive leachings. Figure 5 It can be seen that when the activation time is 1 to 5 hours, each activator and each addition amount can significantly increase the cumulative phosphorus amount leached out of the prepared phosphate fertilizer, which is 464 to 602 mg / kg; but considering the activation effect and electricity cost, the preferred activation time is 1 to 3 hours.

[0053] Effects of fertilizers on soil water-soluble phosphorus and available phosphorus content

[0054] The 25 kinds of composite activated phosphate rock powder prepared in the above examples were added to the soil (the test soil was taken from the Hutubi Experimental Station in Urumqi), with no phosphate fertilizer (CK) and only phosphate rock powder (PR) added as controls, a total of 27 treatments; each treatment was repeated 3 times, a total of 81 pots; 300g soil per pot, 3.00g fertilizer / pot, 100ml water. Samples were taken on the 2nd, 5th, 10th, 20th, 35th, 55th, 75th, 95th, and 120th days, and then the water-soluble phosphorus and available phosphorus content of the soil were determined.

[0055] The changes of water-soluble phosphorus and available phosphorus in the soil after the long-acting phosphorus fertilizer of the present invention (due to the large number of fertilizer types, the average of 25 prepared phosphorus fertilizers was selected) was applied to the soil are as follows: Figure 6 and 7 As shown:

[0056] Figure 6It is the change of soil water-soluble phosphorus after the long-acting phosphate fertilizer of the present invention is applied to soil. As can be seen from the figure, compared to phosphate rock powder (middle blue line), the prepared phosphate fertilizer of the present invention (upper red line) is applied to soil and soil water-soluble phosphorus is significantly improved, and a significant improvement occurs on the 10th day, although there is a drop afterwards, but a significant increase occurs again on the 35th day or so, and its amount is much higher than phosphate rock powder and no addition of phosphate fertilizer (CK) (bottommost gray line), and the duration of the soil water-soluble phosphorus is accumulated even if it exceeds 120 days, and there is no obvious downward trend. It can be proved that the phosphorus release of the long-acting phosphate fertilizer of the present invention is a long-term slow release, which just matches the phosphorus demand of crops, and is particularly suitable for perennial crops.

[0057] Figure 7 It is the change of soil available phosphorus after the long-acting phosphate fertilizer of the present invention is applied to the soil. As can be seen from the figure, the soil available phosphorus content increases significantly after the phosphate fertilizer (the top red line) prepared by the present invention is applied to the soil, reaches a peak value on the 10th day, and then falls back, but rises to a high point again on the 35th day, and then falls back slightly and is in a relatively flat state, which is always higher than the effect of phosphate rock powder. In addition, even if the duration exceeds 120 days, there is no obvious downward trend like phosphate rock powder PR (middle blue line) and CK (bottom gray line). It is explained that the long-acting phosphate fertilizer of the present invention is very effective in increasing the available phosphorus in the soil, and there is a slow release effect, so the long-term demand of perennial crops for phosphorus can be better met.

[0058] Therefore, the long-acting phosphate fertilizer obtained according to the preparation method of the present invention can continuously release phosphorus when applied to the soil, and its fertilizer effect is moderate, so it is suitable for perennial crops; and because of its environmental friendliness and low cost, it can be used in green or organic agriculture.

Claims

1. A method for preparing a long-acting phosphate fertilizer, characterized in that: The steps include: Step 1: Put the phosphate rock powder into a container, add the activator and additives into the container, stir these substances evenly, and then add water to continue stirring and mixing; Step 2: placing the container containing the uniformly mixed substance in step 1 in an ultrasonic generator, and performing ultrasonic activation at 300W and 40kHz; Step 3: taking out the material after ultrasonic activation in step 2 from the ultrasonic generator, and naturally air-drying or drying it to obtain a long-acting phosphate fertilizer.

2. The preparation method according to claim 1, characterized in that: In step 1, the activator is selected from any one of weathered coal, amino acid ionic liquid, industrial alkali lignin, industrial sodium (potassium) lignin sulfonate or fiber viscose sludge, and its added amount is 10 to 50 parts by mass relative to 100 parts by mass of phosphate rock powder. The auxiliary agent is anhydrous sodium sulfite, and its added amount is 10 to 50 parts by mass relative to 100 parts by mass of phosphate rock powder.

3. The preparation method according to claim 1, characterized in that: In the step 2, the ultrasonic activation is performed for 1 to 5 hours.

4. The preparation method according to claim 1, characterized in that: The phosphate rock powder is a low-grade phosphate rock powder having a phosphorus content greater than 16% in terms of P2O5 and a mesh size of 80-100.

5. An application, characterized in that: The long-release phosphate fertilizer obtained by the preparation method according to any one of claims 1 to 4 is used in perennial crops.

Images