A kind of alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer and preparation method thereof

Abstract

The invention provides an alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer and a preparation method thereof. The alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer comprises an ore component and a coagulant component, wherein the weight ratio of the ore component to the coagulant component is (0.01-0.2):1, and the ore component comprises phosphate rock, alkali slag, olivine, potassium feldspar and basalt. The invention effectively utilizes silicon dioxide in potassium feldspar to produce a synergistic effect with basalt to reduce the calcination temperature, saves production costs, and the basalt and olivine components can enhance the ability of the compound fertilizer to adjust the pH of acidic soil, while achieving carbon fixation and emission reduction.

Description

Technical Field

[0001] The invention relates to the field of fertilizers for improving acidic soil, and in particular to an alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer and a preparation method thereof. Background Art

[0002] my country has a vast territory, and agricultural land occupies a large part of the area. In agriculture, the use of fertilizers to increase crop yields is a common method. However, long-term and unreasonable application of fertilizers will lead to a series of problems such as soil acidification and compaction. When soil acidification occurs, the activity of heavy metals in the soil increases, which will seriously affect the quality and safety of agricultural products such as animals and plants, and will cause nutrient loss in the soil, and change the living environment of animals, plants and microorganisms. Therefore, soil acidification seriously restricts the sustainable development of agricultural production.

[0003] Soil is the main source of nutrients needed by crops, and the supply level of various elements in the soil directly affects the growth of crops. With the continuous increase in crop yields, the consumption of various elements in the soil has also increased. Silicon calcium magnesium phosphorus and potassium fertilizer is a new type of alkaline fertilizer. Its aqueous solution is alkaline and can significantly improve acidic soil. It is rich in phosphorus and potassium. It also contains a large amount of silicon, calcium, iron, aluminum, and magnesium. It can balance plant nutrition and improve plant yield and quality. At present, the preparation of silicon calcium potassium magnesium fertilizer using potassium feldspar and alkali slag as raw materials is an important method for producing slow-release phosphorus and potassium fertilizers.

[0004] Alkali residue refers to the alkaline waste residue discharged during the alkali production and alkali treatment process in industrial production. The main components include calcium carbonate, calcium sulfate, calcium chloride, etc., and the alkali residue solution is alkaline, with a pH value of about 10. It is understood that for every ton of soda ash produced, 0.3 to 0.6 tons of waste residue will be discharged, and the alkali residue discharged by alkali plants in many parts of the country is piled up in large quantities around the plant area, causing serious impact on the environment. Therefore, the effective use of alkali residue and turning waste into treasure have obvious social and economic benefits and broad prospects. In addition to being used to prepare cement and other materials, alkali residue can also be used as a soil conditioner. Although there have been studies that directly use alkali residue as a soil conditioner instead of lime to directly act on the improvement of acidic and slightly acidic soils, adjust the pH of the soil, and can increase the activity of soil microorganisms to a certain extent, promote the decomposition of organic matter, and supplement soil trace elements, the existing technology mainly prepares alkali residue into calcium and magnesium fertilizers, which has limited supply of nutrients in the soil, especially for a large number of elements required during crop growth. Alkali slag contains substances such as calcium carbonate, which can be calcined at high temperature with phosphate rock and potassium feldspar under the action of solvent to produce calcium magnesium phosphate fertilizer.

[0005] The reserves of water-insoluble potassium salt resources with potassium feldspar as the main phase in my country are estimated to exceed 20Gt. Phosphate ore resources are also abundant, but most of them are medium- and low-content phosphate ores. Therefore, the conversion rate of water-insoluble potassium salts into effective potassium is not high during the industrial production of silicon-calcium-potassium-magnesium fertilizers, and the utilization rate of phosphate ores is also low. Although the silicon-calcium-potassium-magnesium fertilizers currently produced in my country can significantly improve acidic soils and increase the pH value of soils, they need to be prepared at ultra-high temperatures, usually above 1100°C, with high preparation costs, and low effective nutrient content and easy loss. Summary of the invention

[0006] The purpose of the present invention is to provide an alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer and a preparation method thereof, so as to improve the problems of low mineral nutrient conversion rate, high calcination temperature, few nutrient types and low content in traditional alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer.

[0007] The invention provides an alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer, comprising an ore component and a coagulant component, wherein the weight ratio of the ore component to the coagulant component is (0.01-0.2):1, and the ore component comprises phosphate rock, alkali slag, olivine, potassium feldspar and basalt.

[0008] Compared with the prior art, the present invention adds basalt as an ore raw material, and during the calcination process, the basalt and other minerals are solid-phase fused to form a porous structure with a slow-release function. The basalt is rich in metal oxides such as SiO2, K2O, Na2O, CaO, Fe2O3, FeO and MgO, which can not only improve the nutrient content of the alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer and enrich the nutrient types of the alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer, but also is an important flux, which can effectively reduce the calcination requirement temperature and reduce production costs; potassium feldspar and phosphate rock are the main sources of K2O and P2O5, respectively; olivine and alkali slag are alkaline materials containing a large amount of CaO and MgO, which can effectively reduce the pH value of acidic soil and improve the structure of acidic soil; the diverse ore raw materials can not only provide a variety of nutrients, enrich the nutrient types of the alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer, but also fuse with each other to activate nutrients, thereby further improving the nutrient content of the alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer.

[0009] Preferably, the weight proportions of the phosphate rock, alkali residue, olivine, potassium feldspar and basalt in the ore components are respectively:

[0010] Phosphate rock 15-25 parts;

[0011] 25-32 parts of alkali residue;

[0012] Peridot 20-28 parts;

[0013] Potassium feldspar 15-25 parts;

[0014] 2-8 parts of basalt.

[0015] Phosphate rock and potassium feldspar are selected as the main components to ensure the provision of sufficient phosphorus and potassium sources. The silicon dioxide of basalt, olivine and potassium feldspar can play a synergistic role as calcination aids, reduce the calcination temperature and save production costs. The calcium and magnesium in the alkali slag and olivine after calcination can react with the hydrogen ions in the acidic soil to generate calcium ions and water, thereby increasing the pH of the soil. Subsequently, the calcium ions and magnesium ions can further react with the carbon dioxide dissolved in the soil to generate calcium carbonate and magnesium carbonate, reducing the carbon dioxide burden in the environment and achieving the effect of carbon fixation. The main component of phosphate rock is phosphorus, the main component of alkali slag is calcium, the main component of olivine is magnesium iron and silicon, the main component of potassium feldspar is potassium, and the main component of basalt is silicon. The ratio of the total content of silicon dioxide and phosphorus pentoxide to the total content of calcium oxide and magnesium oxide in the formula is controlled to be between 0.9 and 1.4, so that the nutrient activation reaction of the subsequent mineral materials can be maximized.

[0016] Preferably, the particle size of the ore component is 250-300 mesh. Controlling the ore particles to a small particle size can ensure that the ore is heated evenly during the calcination process, and can increase the contact area with water droplets during the water quenching and cooling process. The water droplets can easily penetrate into the particles to completely quench the calcined product, which is conducive to more fully activating different minerals in the subsequent process.

[0017] Preferably, the coagulant is sodium alginate or chitosan. Sodium alginate or chitosan can coagulate the fertilizer product after calcination, and both sodium alginate and chitosan are non-toxic and harmless, and can be quickly degraded after being applied to the soil, and are important environmentally friendly materials.

[0018] The present invention also provides a method for preparing an alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer, which specifically comprises the following steps:

[0019] S1. Prepare ore components, including phosphate rock, alkali slag, olivine, potassium feldspar and basalt;

[0020] S2, mixing the phosphate rock, alkali residue, olivine, potassium feldspar and basalt and putting them into a grinder for grinding, and obtaining a mixed mineral powder after grinding, and sieving it for standby use;

[0021] S3, placing the sieved mixed mineral powder in a calcining kiln for calcining;

[0022] S4, spraying water to cool the calcined product;

[0023] S5. Adding a coagulant component to the water quenching and cooling product, granulating, drying and packaging are performed to obtain the alkaline silicon-calcium-magnesium-phosphorus-potassium fertilizer compound fertilizer.

[0024] Preferably, the calcination conditions of step S3 are as follows: calcination at a temperature of 800-950° C. for 20-50 min. When the mixed mineral powder is calcined under high temperature conditions, the solid phases of the minerals will fuse with each other to form a loose porous structure. The fused part controls the slow release of nutrients, reduces the volatilization and loss of the compound fertilizer, and the loose porous structure can increase the contact area between the compound fertilizer and the soil, thereby enhancing the effect of the compound fertilizer on adjusting the pH value of the soil.

[0025] Preferably, the weight ratio of the mixed mineral powder to the water in step S4 is (0.08-0.15): 1. The water quenching treatment using a suitable material-water ratio can reduce the temperature of the calcined product and fix the structure of the calcined product, making its porous structure not easy to break; using spraying water for water quenching can allow water droplets to densely and evenly cover the calcined product, thereby improving the cooling efficiency; water quenching treatment can promote the conversion of non-water-soluble potassium salts and phosphate rock in potassium feldspar into effective potassium and effective phosphorus, respectively, greatly improving the degree of nutrient activation in minerals, thereby increasing the nutrient content of alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer.

[0026] Preferably, the sieve in step S2 is a 200-mesh sieve. Sieving can make the mixed mineral powder more uniform, and grinding can control the mixed mineral powder to a small particle size. Small-particle ore is calcined and heated more thoroughly, and the fusion phase of each mineral is more uniform, and reacts more fully in the subsequent process.

[0027] Preferably, the granulation in step S5 adopts a disc extrusion granulation process.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] First, adding basalt components and silica in potassium feldspar as calcination aids can reduce the temperature required for calcination and save production costs. This fertilizer is rich in CaO and MgO, which can react with carbon dioxide dissolved in the soil to produce calcium carbonate and magnesium carbonate, which can not only provide sufficient nutrients, but also have the effect of carbon fixation and emission reduction.

[0030] Secondly, the preparation method of the present invention can improve the conversion rate of potassium feldspar and medium- and low-grade phosphate rock into effective potassium and effective phosphorus, thereby improving the nutrient content of the alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer.

[0031] Third, the present invention adopts a spraying water quenching treatment method to cool the calcined product, which can not only quickly cool the calcined product and cool and fix the structure of the molten mineral, but also improve the rigidity of the calcined product and enhance the slow-release ability of the alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer. Moreover, the degree of activation of mineral nutrients in the calcined product is increased during the water quenching process, further improving the nutrient content of the alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The process flow chart of the preparation method of alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer in a specific embodiment of the present invention;

[0033] Figure 2 This is a product diagram of alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer in a specific embodiment of the present invention;

[0034] Figure 3 This is a comparison chart of the fertilizer preservation effect of two compound fertilizers F2 and F3 purchased from the market and the present invention;

[0035] Figure 4 The figure is a comparison chart of the carbon fixation effect and pH value improvement effect of two compound fertilizers F2 and F3 purchased from the market according to the present invention. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0037] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0038] The embodiment of the present invention discloses a method for preparing an alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer, Figure 1 As shown, the preparation method comprises the following steps:

[0039] S1. Weigh phosphate ore, alkali residue, olivine, potassium feldspar and basalt as mineral raw materials. The weight proportions of phosphate ore, alkali residue, olivine, potassium feldspar and basalt are: 30-40 parts of phosphate ore, 18-28 parts of alkali residue, 10-20 parts of olivine, 20-30 parts of potassium feldspar and 2-8 parts of basalt. In a specific implementation manner, the weight ratio of each ore raw material can be adjusted within the above range.

[0040] In this specific embodiment, phosphate rock, alkali slag and potassium feldspar are selected as main components to prepare a multi-mineral alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer rich in silicon, calcium, magnesium, phosphorus and potassium as main elements. Basalt and olivine are rich in calcium ions and magnesium ions. These two alkaline metal ions can react with carbon dioxide dissolved in soil moisture to generate calcium carbonate solid and magnesium carbonate solid, while effectively increasing the pH value of the soil, highlighting that the present invention can not only improve acidic soil, but also has the effect of carbon sequestration and emission reduction.

[0041] S2, the ore raw materials are mixed uniformly according to the weight ratio and then put into a crusher for grinding, the ore raw materials are ground into a mixed powder of 250-350 mesh and then sieved through a 200 mesh sieve for standby use; the ore raw materials are ground into powder and then sieved, and the mixed powder is controlled within a small particle size range, which can improve the calcination efficiency, and make the mixed powder heated uniformly, and the particles of the mixed powder can also be fully quenched in the subsequent water quenching process;

[0042] S3. Put the mixed powder into a calcining kiln for calcining, control the temperature of the calcining kiln at 800-950°C, and calcine for 20-50 minutes; basalt and olivine cooperate with the silicon dioxide in potassium feldspar as calcining aids to greatly reduce the temperature required for calcination, which not only saves production costs but also improves the safety factor of production. The minerals in the molten state combine with each other to form a loose porous structure. The porous structure can increase the contact area between the alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer and the soil, effectively increase the pH value of the soil, and at the same time maintain the slow release ability to prevent the nutrient loss too quickly;

[0043] S4, after taking out the calcined product, spray water quenching treatment while hot, the specific steps are spraying clean water on the calcined product, waiting for cooling, and the weight ratio of the mixed powder to the spraying water is (0.08-0.15):1. The use of spraying water quenching can make the water droplets densely and evenly cover the calcined product, improve the cooling efficiency, and when the material-water ratio of (0.08-0.15):1 is used, the conversion rate of the non-water-soluble potassium salt and phosphate rock in potassium feldspar into effective potassium and effective phosphorus is the best, that is, the nutrient content of the alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer is maximized;

[0044] S5. Add a coagulant to the cooled water-quenched product, and after the water-quenched product is fully condensed, put it into a disc extrusion granulator for granulation. After the granulation is completed, the product particles are dried, and the product is packaged after drying to obtain a finished alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer.

[0045] The following examples detect the water-soluble and available nutrient contents of fertilizers by graded and stepwise extraction of water-soluble elements, available elements and poorly soluble elements of fertilizers.

[0046] Example 1

[0047] S1. Weigh ore raw materials, including 20 parts of phosphate rock, 28 parts of alkali slag, 22 parts of olivine, 20 parts of potassium feldspar and 10 parts of basalt;

[0048] S2, mix the raw materials of S1 evenly and pour them into a pulverizer to grind them to obtain a 350-mesh mixed powder, and sieve the mixed powder through a 200-mesh sieve for later use;

[0049] S3, placing the mixed powder into a calcining kiln and calcining at 800°C for 25 minutes;

[0050] S4, spraying the calcined product with water quenching, the weight ratio of the mixed powder to the water is 0.08:1;

[0051] S5. Add a coagulant to the cooled water-quenched product, and after sufficient coagulation, perform disc extrusion granulation, dry, and package to obtain a finished alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer.

[0052] Example 2

[0053] S1. Weigh ore raw materials, including 25 parts of phosphate rock, 25 parts of alkali slag, 25 parts of olivine, 20 parts of potassium feldspar and 5 parts of basalt;

[0054] S2, mix the raw materials of S1 evenly and pour them into a pulverizer to grind them to obtain a 250-mesh mixed powder, and sieve the mixed powder through a 200-mesh sieve for later use;

[0055] S3, placing the mixed powder into a calcining kiln and calcining at 950°C for 50 minutes;

[0056] S4, spraying the calcined product with water quenching, the weight ratio of the mixed powder to the water is 0.15:1;

[0057] S5. Add a coagulant to the cooled water-quenched product, and after sufficient coagulation, perform disc extrusion granulation, dry, and package to obtain a finished alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer.

[0058] Example 3

[0059] S1. Weigh ore raw materials, including 17 parts of phosphate rock, 32 parts of alkali slag, 28 parts of olivine, 15 parts of potassium feldspar and 8 parts of basalt;

[0060] S2, mix the raw materials of S1 evenly and pour them into a pulverizer to grind them to obtain a 280-mesh mixed powder, and sieve the mixed powder through a 200-mesh sieve for later use;

[0061] S3, placing the mixed powder into a calcining kiln and calcining at 900°C for 45 minutes;

[0062] S4, spraying the calcined product with water quenching, the ratio of the mixed powder to water is 0.12:1;

[0063] S5. Add a coagulant to the cooled water-quenched product, and after sufficient coagulation, perform disc extrusion granulation, dry, and package to obtain a finished alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer.

[0064] Example 3 is a preferred embodiment of the present invention. The prepared F1 alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer product is compared with two silicon-calcium-magnesium-phosphorus-potassium compound fertilizers F2 and F3 available on the market. The comparison results are as follows:

[0065] Combination Figure 3 a. Figure 3 b. Figure 3 c and Figure 3 As shown in d, a certain amount of mineral fertilizer F1 is weighed and placed in water for leaching for 15 minutes, and then the filtrate is centrifuged and added to the residue for further extraction. The operation steps are the same as above, and the filtrate is taken after centrifugation. The extraction methods of F2 and F3 are the same as F1. Figure 3 It can be seen that the potassium, sodium, calcium and magnesium contents of F1 in the two extracts are significantly higher than those of F2 and F3.

[0066] Combination Figure 4 a. Figure 4 b and Figure 4 c, 30 g of farmland soil was weighed into a 50 ml culture bottle, and 1% F1 mineral fertilizer was added to the mixture and placed in a culture room at 25°C for culture. Gas was collected on days 1, 2, 3, 4, 5, 7, 9, 11, 13, 15, 20, 25, 30, and 45 of culture, and soil samples were destructively collected on day 45 to determine soil pH, where the gas was determined by gas chromatography. F2 and F3 were also cultured under the same conditions.

[0067] Combination Figure 4 a. Figure 4 b and Figure 4 c, the results show that when F1, F2 and F3 compound fertilizers are added to acidic soil, the amount of soil carbon mineralization is calculated by detecting the CO2 content in the gas. Figure 4 a and Figure 4 b It can be seen that the carbon mineralization rate of fertilizer F1 is lower than that of other mineral fertilizers; Figure 4 c It can be seen that after 45 days of applying mineral fertilizers to the soil, fertilizers F1, F2, and F3 can increase the pH value of the soil compared with CK.

[0068] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. An alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer, characterized in that: It comprises an ore component and a coagulant component, wherein the ore The weight ratio of the component to the coagulant component is (0.01-0.2):1, and the ore component includes phosphate rock, alkali residue, olive Stone, potassium feldspar and basalt; the ore components The weight proportions of the phosphate rock, alkali residue, olivine, potassium feldspar and basalt are respectively: Phosphate rock 15-25 parts; 25-32 parts of alkali residue; Peridot 20-28 parts; Potassium feldspar 15-25 parts; 2-8 parts of basalt; The coagulant component is sodium alginate or chitosan; The alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer is prepared by the following preparation method: The following steps are involved: S1. Prepare ore components, including phosphate rock, alkali slag, olivine, potassium feldspar and basalt; S2, mixing the phosphate rock, alkali residue, olivine, potassium feldspar and basalt and putting them into a pulverizer for grinding, and grinding to obtain Mix the mineral powder and sieve for later use; S3, placing the sieved mixed mineral powder in a calcining kiln for calcining; S4, spraying water to cool the calcined product; S5, adding a coagulant component to the water quenching and cooling product, granulating, drying and packaging to obtain the alkaline calcium magnesium silicate Phosphorus and potassium compound fertilizer.

2. The alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer according to claim 1, characterized in that: The particle size of the ore components It is 250-300 mesh.

3. The alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer according to claim 1, characterized in that: The steps The calcination conditions of S3 are as follows: calcination at a temperature of 800-950°C for 20-50 min.

4. The alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer according to claim 1, characterized in that: The mixing The weight ratio of the mineral powder to the water in step S4 is (0.08-0.15):

1.

5. The alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer according to claim 1, characterized in that: The steps The S2 medium sieve uses a 200-mesh sieve.

6. The alkaline silicon-calcium-magnesium-phosphorus-potassium compound fertilizer according to claim 1, characterized in that: The steps The granulation of S5 adopts the disc extrusion granulation process.

Images