Compound fertilizer prepared from phosphate tailings and crop straws and preparation method of compound fertilizer

Abstract

The invention relates to an environment-friendly utilization technology of industrial tailings and agricultural wastes, in particular to a compound fertilizer prepared from phosphate tailings and crop straws and a preparation method of the compound fertilizer. The compound fertilizer comprises powder formed by calcining and crushing basic raw materials and additives, and the powder is further processed and granulated to obtain the phosphate tailing compound fertilizer. The basic raw materials comprise the following components in parts by weight: 80-90 parts of phosphate tailings and 5-10 parts of plant straws; the weight part of the additive is 2-6 parts, and the weight part of the granulating agent is 3-4 parts. The compound fertilizer can be prepared by using the phosphate tailings and the crop straws as main raw materials, is simple in preparation process, low in cost and good in fertilizer efficiency, and can be applied instead of a calcium magnesium phosphate fertilizer.

Description

Technical Field

[0001] The invention relates to environmentally friendly utilization technology of industrial tailings and agricultural wastes, in particular to a compound fertilizer made from phosphate tailings and crop straws and a preparation method thereof. Background Art

[0002] Phosphate rock is a scarce resource, and the existing phosphate rock reserves are limited. There are no other resources that can replace phosphate rock resources. The market demand for calcium magnesium phosphate fertilizer is still increasing year by year. At present, calcium magnesium phosphate fertilizer is mostly processed with low-grade phosphate rock. Phosphate tailings are industrial wastes produced in the existing phosphate rock production process after crushing and flotation processes. Its main components and weight ratios range from about 5-10% of phosphorus pentoxide, 34-45% of calcium oxide, and 15-25% of magnesium oxide. Since the effective phosphorus content in the tailings is lower than the standard of calcium magnesium phosphate fertilizer (≥12%), it is not suitable for calcium magnesium phosphate fertilizer.

[0003] Phosphate ore is relatively scarce, and the utilization rate of phosphate tailings is less than 10%, with very low utilization value. It is currently mainly used as roadbed materials and mine backfill materials. Other applications, such as the separation and production of magnesium carbonate, have too high production costs and almost no economic value. In addition, the effective phosphorus content in phosphate tailings is far lower than the standard of calcium magnesium phosphate fertilizer (above 12%), and it cannot be used directly as calcium magnesium phosphate fertilizer, and is rarely used as a soil conditioner. The country is also actively promoting the full utilization of bulk by-products. Therefore, it is very important to explore high-value and full-utilization resource methods for phosphate tailings.

[0004] Crop straw is the main waste of agricultural production. An average of about 700 million tons of straw is produced each year, and the resource utilization rate after leaving the field is less than 40%. More than 50% of the straw is directly returned to the field, which will cause an increase in pests and weeds, a corresponding increase in the amount of pesticides, an increase in planting costs, and an impact on crop rotation, resulting in a decrease in the utilization rate of cultivated land and a decrease in per-acre output value. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a phosphate tailings compound fertilizer which can use phosphate tailings and crop straw as main raw materials to manufacture phosphate tailings compound fertilizer, and at the same time has simple preparation process, low cost and good fertilizer effect, and can replace calcium magnesium phosphate fertilizer for application.

[0006] The compound fertilizer made from phosphate tailings and crop straws comprises powder obtained by calcining and crushing basic raw materials and additives, and the powder is further processed and granulated to obtain the phosphate tailings compound fertilizer.

[0007] The basic raw material comprises 80-90 parts by weight of phosphorus tailings and 5-10 parts by weight of plant straw; the additive comprises 2-6 parts by weight and the granulating agent comprises 3-4 parts by weight.

[0008] Furthermore, the additive includes 1 to 3 parts by weight of manganese sulfate and 1 to 3 parts by weight of silicon dioxide.

[0009] Furthermore, the composition also contains 3 to 4 parts by weight of a granulating agent, wherein the granulating agent is a mixture of one or more of montmorillonite powder, white clay, kaolin, attapulgite, and bentonite.

[0010] Furthermore, the compound fertilizer of the present invention also contains a phosphorus additive, which is a phosphorus salt or a phosphorus oxide, and the total weight percentage of the phosphorus element in the phosphorus additive and the phosphorus element in the raw material phosphorus tailings in the final product is 7-13%.

[0011] Furthermore, the plant straw is a mixture of one or more of wheat straw, rice straw, corn straw, and rice husk.

[0012] The method for manufacturing compound fertilizer by utilizing phosphorus tailings and crop straws is as follows:

[0013] 80-90 parts by weight of phosphorus tailings, 5-10 parts of plant straws and 2-6 parts of additives are calcined, cooled and then crushed into 70-300 mesh powder in a ball mill, and then 3-4 parts of granulating agents are added and mixed to obtain a compound fertilizer product.

[0014] Furthermore, the calcination process is carried out in a rotary kiln at 300-350° C. for 1-1.5 hours, and then at 900-950° C. for 1-2 hours.

[0015] The positive effect of the present invention is that phosphate tailings and straw are used as main raw materials, and phosphate tailings compound fertilizer is obtained through deep processing. The actual sample test results of the compound fertilizer show that the compound fertilizer has a good pore structure and a specific surface area of ​​5.81m 2 / g. The ingredients contain balanced phosphorus pentoxide, calcium oxide, magnesium oxide and biochar. The material has a certain alkalinity, and the pH value of the aqueous solution is 9-10. The alkalinity is mild and will not harm the soil. The porous properties of the material can effectively improve the effective absorption of calcium, magnesium and phosphorus by crops. The presence of biochar and additives also has the function of improving the soil microenvironment. DETAILED DESCRIPTION

[0016] Embodiment 1:

[0017] 80 kg of phosphate tailings, 10 kg of wheat straw, 3 kg of manganese sulfate and 3 kg of silicon dioxide are calcined in a rotary kiln at 350°C for 1 hour, then calcined at 900°C for 2 hours, and then ground into a 100-mesh powder product in a ball mill after cooling; ammonium phosphate is added to the powder product to adjust the weight content of effective phosphorus to 9%; the adjusted material is added with 4 kg of montmorillonite powder for granulation to obtain a phosphate tailings compound fertilizer.

[0018] After testing, its BET specific surface area is 5.81m 2 / g; total pore volume is 0.0247m 3 / g, mainly mesopores; the average pore diameter is 9.5336nm, and the mesopore diameter is 27.87nm.

[0019] The product obtained in Example 1 was tested for performance:

[0020] Test 1-1: Effect of application of phosphate tailings compound fertilizer on the growth of potted peanut plants.

[0021] The phosphate tailings compound fertilizer prepared in Example 1, compound fertilizer on the market, and calcium magnesium phosphate fertilizer were used to verify the fertilizer efficiency in a peanut pot test. The test soil was taken from the Yingtan Station of the Red Soil Ecological Experiment Station of the Institute of Soil Science, Chinese Academy of Sciences. Table 1 shows the test result data.

[0022] Table 1 Peanut potted plant test verifies the fertilizer performance of phosphate tailings compound fertilizer

[0023]

[0024]

[0025] Fertilizers and application rates in Table 1:

[0026] 1. Usage of compound fertilizer 1 (15:15:15): Use compound fertilizer sold on the market with a nitrogen, phosphorus and potassium content of (15:15:15) and a dosage of 50 kg / mu;

[0027] 2. Usage of compound fertilizer 2 (containing calcium magnesium phosphate): 19.6 kg / mu of urea, 60 kg / mu of commercially available calcium magnesium phosphate (effective phosphorus content 12%), and 12.1 kg / mu of potassium chloride;

[0028] 3. Usage of compound fertilizer in Example 1: 19.6 kg / mu of urea, 80 kg / mu of compound fertilizer in Example 1 (the dosage is based on the equivalent of 60 kg / mu of calcium magnesium phosphate fertilizer with an effective phosphorus content of 12%, to ensure that the effective ingredient P2O5 is equivalent to its dosage), and 12.1 kg / mu of potassium chloride.

[0029] After 126 days of potted plant test, the results in Table 1 show that the compound fertilizer of Example 1 has a significant yield-increasing effect, which is 1.59 times that of no fertilizer, 1.22 times that of commercially available compound fertilizer, and 1.08 times that of commercially available calcium magnesium phosphate fertilizer. The fertilizer effect of phosphate tailings compound fertilizer is better than that of commercially available calcium magnesium phosphate fertilizer, and can completely replace commercially available calcium magnesium phosphate fertilizer.

[0030] Test 1-2: Effect of application of phosphate tailings compound fertilizer on the growth of peanut plants in the field.

[0031] The phosphate tailings compound fertilizer prepared in Example 1 was used for peanut field test at a soil covering rate of 80 kg / mu.

[0032] Experimental location: Yingtan Station of Red Soil Ecological Experimental Station, Nanjing Institute of Soil Science, Chinese Academy of Sciences;

[0033] Trial period: April to September 2024;

[0034] Test soil: The Yingtan Station of the Red Soil Ecological Experiment Station of the Nanjing Institute of Soil Science, Chinese Academy of Sciences, conducted a trial on the fertilizer effect of phosphorus tailings compound fertilizer on peanut planting. Soil and harvest peanut kernel samples were collected from the site and brought back to the laboratory for soil physical and chemical properties and peanut kernel weight analysis. The test results are shown in Table 2.

[0035] Table 2 Comparison of fertilizer effects between phosphate tailings compound fertilizer and other fertilizers

[0036] Serial number Yield (Kg / mu) 1 Compound fertilizer 1 (15:15:15) 29 2 Compound fertilizer 2 (containing calcium magnesium phosphate fertilizer) 113 3 Phosphate tailings compound fertilizer of embodiment 1 271

[0037] Fertilizers and application rates in Table 2:

[0038] 1. Usage of compound fertilizer 1 (15:15:15): Use compound fertilizer sold on the market with a nitrogen, phosphorus and potassium content of (15:15:15) and a dosage of 50 kg / mu;

[0039] 2. Usage of compound fertilizer 2 (containing calcium magnesium phosphate): 19.6 kg / mu of urea, 60 kg / mu of commercially available calcium magnesium phosphate (effective phosphorus content 12%), and 12.1 kg / mu of potassium chloride;

[0040] 3. Usage of compound fertilizer in Example 1: 19.6 kg / mu of urea, 80 kg / mu of compound fertilizer in Example 1 (the dosage is based on the equivalent of 60 kg / mu of calcium magnesium phosphate fertilizer with an effective phosphorus content of 12%, to ensure that the effective ingredient P2O5 is equivalent to its dosage), and 12.1 kg / mu of potassium chloride.

[0041] The data in Table 2 show that after field tests, the yield-increasing effect of the phosphate tailings compound fertilizer is very significant, which is 9.3 times that of compound fertilizer and 2.4 times that of calcium magnesium phosphate fertilizer. The peanut yield of local normal fertile cultivated land is about 220 kg / mu, and the yield of the phosphate tailings compound fertilizer using Example 1 is 1.2 times the local normal yield.

[0042] Test 1-3: Effect of phosphate tailings compound fertilizer application on the growth of peanut plants in the field.

[0043] The phosphate tailings compound fertilizer prepared in Example 1 was used for peanut field test at a soil covering rate of 80 kg / mu.

[0044] Experimental location: Ji'an Station of Red Soil Ecological Experimental Station, Nanjing Institute of Soil Science, Chinese Academy of Sciences;

[0045] Trial period: April to September 2024;

[0046] Test soil: The Red Soil Ecological Experiment Station of Nanjing Institute of Soil Science, Chinese Academy of Sciences, conducted a trial on the fertilizer effect of phosphorus tailings compound fertilizer on peanut planting. Soil and harvest peanut kernel samples were collected from the site and brought back to the laboratory for soil physical and chemical properties and peanut kernel weight analysis.

[0047] Table 3 Comparison of fertilizer effects between phosphate tailings compound fertilizer and other fertilizers

[0048] Serial number Yield (Kg / mu) 1 Compound fertilizer 1 (15:15:15) 160.2 2 Compound fertilizer 2 (containing calcium magnesium phosphate fertilizer) 251.7 3 Phosphate tailings compound fertilizer of embodiment 1 288.4

[0049] Fertilizers and application rates in Table 3:

[0050] 1. Usage of compound fertilizer 1 (15:15:15): Use compound fertilizer sold on the market with a nitrogen, phosphorus and potassium content of (15:15:15) and a dosage of 50 kg / mu;

[0051] 2. Usage of compound fertilizer 2 (containing calcium magnesium phosphate): 19.6 kg / mu of urea, 60 kg / mu of commercially available calcium magnesium phosphate (effective phosphorus content 12%), and 12.1 kg / mu of potassium chloride;

[0052] 3. Usage of compound fertilizer in Example 1: 19.6 kg / mu of urea, 80 kg / mu of compound fertilizer in Example 1 (the dosage is based on the equivalent of 60 kg / mu of calcium magnesium phosphate fertilizer with an effective phosphorus content of 12%, to ensure that the effective ingredient P2O5 is equivalent to its dosage), and 12.1 kg / mu of potassium chloride.

[0053] The data in Table 3 show that after field tests, the yield-increasing effect of phosphate tailings compound fertilizer is very significant, which is 1.8 times that of compound fertilizer and 1.15 times that of calcium magnesium phosphate fertilizer. The peanut yield of local normal fertility farmland is about 220 kg / mu, and the yield of phosphate tailings compound fertilizer is 1.31 times the local normal yield.

[0054] Embodiment 2:

[0055] 90 kg of phosphate tailings, 5 kg of wheat straw, 1 kg of manganese sulfate and 1 kg of silicon dioxide are calcined in a rotary kiln at 350°C for 1 hour, then calcined at 900°C for 2 hours, and then ground into a 100-mesh powder product in a ball mill after cooling; ammonium phosphate is added to the powder product to adjust the weight content of effective phosphorus to 9%; 3 kg of attapulgite powder is added to the adjusted material for granulation to obtain a phosphate tailings compound fertilizer.

[0056] The product obtained in Example 2 was tested for performance:

[0057] Test 2-1: Effect of application of phosphate tailings compound fertilizer on the growth of potted peanut plants.

[0058] The phosphate tailing compound fertilizer prepared in Example 2, compound fertilizer on the market, and calcium magnesium phosphate fertilizer were used to verify the fertilizer effect in a peanut pot test. The test soil was taken from the Yingtan Station of the Red Soil Ecological Experiment Station of the Institute of Soil Science, Chinese Academy of Sciences. The results are shown in Table 4.

[0059] Table 4 Peanut potted plant test verifies the fertilizer performance of phosphate tailings compound fertilizer

[0060] Serial number fertilizer Yield (Kg / mu) 1 No fertilizer 14.4 2 Compound fertilizer 1 (15:15:15) 18.8 3 Compound fertilizer 2 (containing calcium magnesium phosphate fertilizer) 21.3 4 Phosphate tailings compound fertilizer of embodiment 2 20.0

[0061] Fertilizers and application rates in Table 4:

[0062] 1. Usage of compound fertilizer 1 (15:15:15): Use compound fertilizer sold on the market with a nitrogen, phosphorus and potassium content of (15:15:15) and a dosage of 50 kg / mu;

[0063] 2. Usage of compound fertilizer 2 (containing calcium magnesium phosphate): 19.6 kg / mu of urea, 60 kg / mu of commercially available calcium magnesium phosphate (effective phosphorus content 12%), and 12.1 kg / mu of potassium chloride;

[0064] 3. Usage of compound fertilizer in Example 2: 19.6 kg / mu of urea, 80 kg / mu of compound fertilizer in Example 1 (the dosage is based on the equivalent of 60 kg / mu of calcium magnesium phosphate fertilizer with an effective phosphorus content of 12%, to ensure that the effective ingredient P2O5 is equivalent to its dosage), and 12.1 kg / mu of potassium chloride.

[0065] The data in Table 4 show that after 126 days of potted plant experiments, the yield-increasing effect of phosphate tailings compound fertilizer was significant, which was 1.39 times that of no fertilizer and 1.06 times that of commercially available compound fertilizers. The fertilizer efficiency of phosphate tailings compound fertilizer was lower than that of commercially available calcium magnesium phosphate compound fertilizer.

[0066] Test 2-2: Effect of application of phosphate tailings compound fertilizer on the growth of peanut plants in the field.

[0067] The phosphate tailings compound fertilizer prepared in Example 2 was used for peanut field test at a soil covering rate of 80 kg / mu.

[0068] Experimental location: Yingtan Station of Red Soil Ecological Experimental Station, Nanjing Institute of Soil Science, Chinese Academy of Sciences;

[0069] Trial period: April to September 2024;

[0070] Test soil: The Yingtan Station of the Red Soil Ecological Experiment Station of the Nanjing Institute of Soil Science, Chinese Academy of Sciences, conducted a trial on the fertilizer effect of phosphorus tailings compound fertilizer on peanut planting. Soil and harvest peanut kernel samples were collected from the site and brought back to the laboratory for soil physical and chemical properties and peanut kernel weight analysis. The results are shown in Table 5.

[0071] Table 5 Comparison of fertilizer effects between phosphate tailings compound fertilizer and other fertilizers

[0072] Serial number fertilizer Yield (Kg / mu) 1 Compound fertilizer 1 (15:15:15) 29 2 Compound fertilizer 2 (containing calcium magnesium phosphate fertilizer) 113 3 Phosphate tailings compound fertilizer of embodiment 2 273

[0073] Fertilizers and application rates in Table 5:

[0074] 1. Usage of compound fertilizer 1 (15:15:15): Use compound fertilizer sold on the market with a nitrogen, phosphorus and potassium content of (15:15:15) and a dosage of 50 kg / mu;

[0075] 2. Usage of compound fertilizer 2 (containing calcium magnesium phosphate): 19.6 kg / mu of urea, 60 kg / mu of commercially available calcium magnesium phosphate (effective phosphorus content 12%), and 12.1 kg / mu of potassium chloride;

[0076] 3. Usage of compound fertilizer in Example 2: 19.6 kg / mu of urea, 80 kg / mu of compound fertilizer in Example 1 (the dosage is based on the equivalent of 60 kg / mu of calcium magnesium phosphate fertilizer with an effective phosphorus content of 12%, to ensure that the effective ingredient P2O5 is equivalent to its dosage), and 12.1 kg / mu of potassium chloride.

[0077] The data in Table 5 show that after field tests, the yield-increasing effect of phosphate tailings compound fertilizer is very significant, which is 9.4 times that of compound fertilizer and 2.4 times that of calcium magnesium phosphate fertilizer. The peanut yield of local normal fertility farmland is about 220 kg / mu, and the yield of phosphate tailings compound fertilizer is 1.2 times the local normal yield.

[0078] Test 2-3: Effect of application of phosphate tailings compound fertilizer on the growth of peanut plants in the field.

[0079] The phosphate tailings compound fertilizer prepared in Example 2 was used for peanut field test at a soil covering rate of 80 kg / mu.

[0080] Experimental location: Ji'an Station of Red Soil Ecological Experimental Station, Nanjing Institute of Soil Science, Chinese Academy of Sciences;

[0081] Trial period: April to September 2024;

[0082] Test soil: The Red Soil Ecological Experiment Station of Nanjing Institute of Soil Science, Chinese Academy of Sciences, conducted a trial on the fertilizer effect of phosphorus tailings compound fertilizer on peanut planting. Soil and harvest peanut kernel samples were collected from the site and brought back to the laboratory for soil physical and chemical properties and peanut kernel weight analysis. The results are shown in Table 6.

[0083] Table 6 Comparison of fertilizer effects between phosphate tailings compound fertilizer and other fertilizers

[0084] Serial number Yield (Kg / mu) 1 Compound fertilizer 1 (15:15:15) 160.2 2 Compound fertilizer 2 (containing calcium magnesium phosphate fertilizer) 251.7 3 Phosphate tailings compound fertilizer of embodiment 2 245

[0085] Fertilizers and application rates in Table 5:

[0086] 1. Usage of compound fertilizer 1 (15:15:15): Use compound fertilizer sold on the market with a nitrogen, phosphorus and potassium content of (15:15:15) and a dosage of 50 kg / mu;

[0087] 2. Usage of compound fertilizer 2 (containing calcium magnesium phosphate): 19.6 kg / mu of urea, 60 kg / mu of commercially available calcium magnesium phosphate (effective phosphorus content 12%), and 12.1 kg / mu of potassium chloride;

[0088] 3. Usage of compound fertilizer in Example 2: 19.6 kg / mu of urea, 80 kg / mu of compound fertilizer in Example 1 (the dosage is based on the equivalent of 60 kg / mu of calcium magnesium phosphate fertilizer with an effective phosphorus content of 12%, to ensure that the effective ingredient P2O5 is equivalent to its dosage), and 12.1 kg / mu of potassium chloride.

[0089] The data in Table 6 show that after field tests, the yield-increasing effect of phosphate tailings compound fertilizer is 1.53 times that of compound fertilizer, which is close to that of ordinary calcium magnesium phosphate compound fertilizer. The peanut yield of local normal fertility farmland is about 220 kg / mu, and the yield of phosphate tailings compound fertilizer is 1.11 times the local normal yield.

Claims

1. A compound fertilizer made from phosphate tailings and crop straws, characterized in that: the compound fertilizer comprises powder obtained by calcining and crushing a basic raw material and an additive, and the powder is further processed and granulated to obtain a phosphate tailing compound fertilizer. The basic raw material comprises 80 to 90 parts by weight of phosphate tailings and 5 to 10 parts by weight of plant straws; and the additive comprises 2 to 6 parts by weight.

2. The composite fertilizer made from phosphate tailings and crop straw according to claim 1, characterized in that: The additives include 1 to 3 parts by weight of manganese sulfate and 1 to 3 parts by weight of silicon dioxide.

3. The composite fertilizer produced by utilizing phosphate tailings and crop straw according to claim 1, characterized in that: The composition also contains 3-4 parts by weight of a granulating agent, which is a mixture of one or more of montmorillonite powder, white clay, kaolin, attapulgite and bentonite.

4. The composite fertilizer produced by utilizing phosphate tailings and crop straw according to claim 1, characterized in that: The composition also contains a phosphorus additive, which is a phosphorus salt or a phosphorus oxide. The total weight percentage of the phosphorus element in the phosphorus additive and the phosphorus element in the raw material phosphorus tailings in the final product is 7-13%.

5. The composite fertilizer made from phosphate tailings and crop straw according to claim 1, characterized in that: The plant straw is a mixture of one or more of wheat straw, rice straw, corn straw and rice husk.

6. A method for preparing the composite fertilizer according to any one of claims 1 to 5, characterized in that: 80-90 parts by weight of phosphorus tailings, 5-10 parts of plant straw and 2-6 parts of additives are calcined, cooled and then crushed into 70-300 mesh powder in a ball mill, and then 3-4 parts of granulating agent are added and mixed to obtain a compound fertilizer product.

7. The preparation method according to claim 6, characterized in that: The calcination process is to calcine at 300-350° C. for 1-1.5 hours in a rotary kiln, and then calcine at 900-950° C. for 1-2 hours.

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