A preparation method of industrial rare earth ammonium sulfate alkaline soil conditioner

Abstract

The invention discloses a preparation method of an industrial rare earth ammonium sulfate saline-alkali soil conditioner, and relates to the technical field of wastewater treatment. Specifically, the method comprises the following steps: S1, taking rare earth smelting ammonium sulfate waste liquid, adding a KOH solution thereto, taking a supernatant, and obtaining a superior rare earth ammonium sulfate material; S2, adding a humic acid solution to the superior rare earth ammonium sulfate material, and obtaining a solution one; S3, adding a mineral source potassium humate solution to the solution one, and obtaining a solution two; S4, adding a wood vinegar solution to the solution two and mixing evenly, and obtaining a solution three; S5, freeze-drying the solution three, and obtaining the industrial rare earth ammonium sulfate saline-alkali soil conditioner material. The invention uses the treated superior rare earth ammonium sulfate as a main raw material, adds humic acid, mineral source potassium humate, wood vinegar and other components, and performs a directional modification treatment on the superior rare earth ammonium sulfate, and obtains the saline-alkali soil conditioner material.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, in particular to a method for preparing an industrial rare earth ammonium sulfate alkaline soil conditioner. Background Art

[0002] Rare earths are a strategic resource that are highly valued by people. Baotou City, Inner Mongolia is the largest rare earth mineral storage base in the country. The industrial reserves of rare earth minerals in the Bayan Obo Iron Mine are as high as 57.38 million tons. Rare earth resources account for 62% of the world's total rare earth resources and 87.1% of the country's total rare earth resources.

[0003] However, a large amount of waste liquid is generated during the rare earth mining process. Specifically, for every ton of rare earth elements mined, about 20,000 tons of rare earth smelting ammonium sulfate waste liquid will be generated. These waste liquids contain different concentrations of ammonia nitrogen (10-5000 mg / L), which poses a serious threat to the environment. If this type of waste liquid is directly discharged into the environment, it will not only cause a series of environmental problems, but also lead to the loss of nitrogen, phosphorus and trace rare earth elements (such as lanthanum, cerium, praseodymium, and neodymium). Ammonia nitrogen and phosphorus in rare earth smelting ammonium sulfate waste liquid can be directly used as nutrients for saline-alkali soils. Trace rare earth elements lanthanum, cerium, praseodymium, and neodymium have significant effects on increasing crop yields, improving quality, and enhancing stress resistance and disease resistance.

[0004] Soil salinization, especially salinization due to lack of ammonia nitrogen, is a global ecological problem. The saline-alkali soil in the Hetao Irrigation Area of ​​Inner Mongolia is a representative example. It contains eight ions that are typical for aggravating the salinity effect: calcium, magnesium, sodium, chloride, sulfate, bicarbonate, carbonate, and nitrate, with a pH greater than 8. At the same time, potassium has a positive effect on improving the physical properties of saline-alkali soils. Potassium ions can exchange with other cations on soil colloids, thereby changing the charge characteristics and aggregate stability of soil colloids. For example, increasing Na + The leaching effect of potassium helps improve the aeration and water permeability of the soil, providing a better soil environment for the root growth of crops. At the same time, potassium is one of the essential nutrients for plant growth and is involved in a variety of physiological and biochemical processes, such as photosynthesis, material transport, and cell osmotic regulation. Summary of the invention

[0005] In order to solve the above technical problems, the present invention is based on the existing ammonium sulfate wastewater treatment technology, and is guided by the saline-alkali soil treatment in the Hetao Irrigation Area of ​​Inner Mongolia. The byproduct of the smelting output of the rare earth enterprises in Baotou City - rare earth smelting ammonium sulfate wastewater is treated by "de-harming and enhancing efficiency" and a saline-alkali soil conditioner is compounded to achieve the purpose of regional salinization soil improvement, as follows:

[0006] A method for preparing an industrial rare earth ammonium sulfate alkaline soil conditioner comprises the following steps:

[0007] S1. Take the waste liquid of ammonium sulfate from rare earth smelting, add KOH solution thereto, stir for 10-20 minutes, let stand for 15-25 minutes, take the supernatant, and obtain the superior rare earth ammonium sulfate material;

[0008] S2. Add 15-25 ml of humic acid solution to 200 ml of high-grade rare earth ammonium sulfate material, stir mechanically for 10-20 min, and let stand for 25-35 min to obtain solution 1;

[0009] S3, add 45-55 ml of mineral potassium humate solution to solution 1, mechanically stir for 10-20 min, and let stand for 25-35 min to obtain solution 2;

[0010] S4, add 8-12 ml of wood vinegar solution to solution 2, mix well, and stir for 10-20 minutes to obtain solution 3;

[0011] S5. The solution three is freeze-dried to obtain an industrial rare earth ammonium sulfate alkaline soil conditioner material.

[0012] Moreover, a method for preparing an industrial rare earth ammonium sulfate alkaline soil conditioner comprises the following steps:

[0013] S1, taking rare earth smelting ammonium sulfate waste liquid, adding KOH solution thereto, stirring for 15 minutes and then standing for 20 minutes, taking the supernatant, and obtaining a superior rare earth ammonium sulfate material;

[0014] S2. Add 20 ml of humic acid solution to 200 ml of high-grade rare earth ammonium sulfate material, stir mechanically for 15 min, and let stand for 30 min to obtain solution 1;

[0015] S3, add 50 ml of mineral potassium humate solution to solution 1, mechanically stir for 15 min, and let stand for 30 min to obtain solution 2;

[0016] S4, add 10 ml of wood vinegar solution to solution 2, mix well, and stir for 15 minutes to obtain solution 3;

[0017] S5. The solution three is freeze-dried to obtain an industrial rare earth ammonium sulfate alkaline soil conditioner material.

[0018] Moreover, the concentration of the KOH solution is 4%-6%.

[0019] Moreover, in the humic acid solution, the mass ratio of humic acid to water is 1:3.

[0020] Moreover, in the mineral source potassium humate solution, the mass ratio of mineral source potassium humate to water is 1:50.

[0021] Moreover, in the wood vinegar solution, the mass ratio of wood vinegar to water is 1:3.

[0022] Moreover, in the step S5, during the freeze-drying process, the system is vacuumed to 2.6 MPa and the temperature is -40°C to -60°C.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention adds rare earth smelting ammonium sulfate waste liquid into KOH solution, performs "harm removal and efficiency enhancement" treatment on the rare earth smelting ammonium sulfate waste liquid, and obtains superior rare earth ammonium sulfate material, which not only solves the environmental problems caused by waste liquid discharge, but also converts it into valuable industrial rare earth ammonium sulfate saline-alkali soil conditioner material, reduces the pollution of rare earth smelting ammonium sulfate waste liquid to the environment, and reduces the cost of environmental governance. At the same time, the industrial rare earth ammonium sulfate saline-alkali soil conditioner material improves saline-alkali soil and also helps to improve the ecological environment and enhance the sustainable utilization capacity of land resources.

[0025] 2. The high-grade rare earth ammonium sulfate material prepared by the present invention retains the components such as ammonia nitrogen and phosphorus in the rare earth smelting ammonium sulfate waste liquid that are beneficial to saline-alkali soil, removes the elements such as arsenic, mercury, lead, cadmium, chromium, etc. that are prone to cause heavy metal accumulation effects to the greatest extent, and adds potassium elements that can promote the saline-alkali soil improvement mechanism through KOH solution treatment.

[0026] 3. The present invention uses treated high-grade rare earth ammonium sulfate as the main raw material, adds humic acid, mineral potassium humate and wood vinegar and other ingredients to carry out targeted modification and modification on the high-grade rare earth ammonium sulfate, obtains saline-alkali soil conditioner materials, improves soil fertility and air permeability, provides a better soil environment for crop growth, realizes the recycling of resources, and improves resource utilization efficiency.

[0027] 4. The treatment process of the present invention is simple, and the soil conditioner can be prepared only through physical and mechanical treatment at room temperature and conventional freeze-drying method. It is not only low-cost and can turn waste into treasure, but also has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Photographs were taken to record the growth of alfalfa in Experiment 2. Columns (a), (b), (c), (d), (e), (f), and (g) in the figure respectively show the growth of potted seedlings treated with No. 3, No. 4, No. 6, No. 5, the control group, No. 1, and No. 2.

[0029] Figure 2 This is the root growth of alfalfa in the control group and potted with amendment No. 5 in Experiment 3. DETAILED DESCRIPTION

[0030] Example 1

[0031] A method for preparing an industrial rare earth ammonium sulfate alkaline soil conditioner comprises the following steps:

[0032] S1. Take the waste liquid of ammonium sulfate from rare earth smelting, add KOH solution thereto, stir for 10 minutes, let stand for 15 minutes, take the supernatant, and obtain the superior rare earth ammonium sulfate material;

[0033] S2. Add 15 ml of humic acid solution to 200 ml of high-grade rare earth ammonium sulfate material, stir mechanically for 10 min, and let stand for 25 min to obtain solution 1;

[0034] S3, add 45 ml of mineral potassium humate solution to solution 1, mechanically stir for 10 min, and let stand for 25 min to obtain solution 2;

[0035] S4, add 8 ml of wood vinegar solution to solution 2, mix well, and stir for 10 min to obtain solution 3;

[0036] S5. The solution three is freeze-dried to obtain an industrial rare earth ammonium sulfate alkaline soil conditioner material.

[0037] Moreover, the concentration of the KOH solution is 4%.

[0038] Moreover, in the humic acid solution, the mass ratio of humic acid to water is 1:3.

[0039] Moreover, in the mineral source potassium humate solution, the mass ratio of mineral source potassium humate to water is 1:50.

[0040] Moreover, in the wood vinegar solution, the mass ratio of wood vinegar to water is 1:3.

[0041] Moreover, in the step S5, during the freeze-drying process, the system is vacuumed to 2.6 MPa and the temperature is -40°C to -60°C.

[0042] Example 2

[0043] A method for preparing an industrial rare earth ammonium sulfate alkaline soil conditioner comprises the following steps:

[0044] S1, taking rare earth smelting ammonium sulfate waste liquid, adding KOH solution thereto, stirring for 20 minutes and then standing for 25 minutes, taking the supernatant, and obtaining a superior rare earth ammonium sulfate material;

[0045] S2. Add 25 ml of humic acid solution to 200 ml of high-grade rare earth ammonium sulfate material, stir mechanically for 20 min, and let stand for 35 min to obtain solution 1;

[0046] S3, add 55 ml of mineral potassium humate solution to solution 1, mechanically stir for 20 min, and let stand for 35 min to obtain solution 2;

[0047] S4, add 12 ml of wood vinegar solution to solution 2, mix well, and stir for 20 minutes to obtain solution 3;

[0048] S5. The solution three is freeze-dried to obtain an industrial rare earth ammonium sulfate alkaline soil conditioner material.

[0049] Moreover, the concentration of the KOH solution is 6%.

[0050] Moreover, in the humic acid solution, the mass ratio of humic acid to water is 1:3.

[0051] Moreover, in the mineral source potassium humate solution, the mass ratio of mineral source potassium humate to water is 1:50.

[0052] Moreover, in the wood vinegar solution, the mass ratio of wood vinegar to water is 1:3.

[0053] Moreover, in step S5, during the freeze-drying process, the system is vacuumed to 2.6 MPa and the temperature is -60°C.

[0054] Example 3

[0055] A method for preparing an industrial rare earth ammonium sulfate alkaline soil conditioner comprises the following steps:

[0056] S1. Take the waste liquid of ammonium sulfate from rare earth smelting, add KOH solution thereto, stir for 15 minutes, let stand for 20 minutes, take the supernatant, and obtain the superior rare earth ammonium sulfate material;

[0057] S2. Add 20 ml of humic acid solution to 200 ml of high-grade rare earth ammonium sulfate material, stir mechanically for 15 min, and let stand for 30 min to obtain solution 1;

[0058] S3, add 50 ml of mineral potassium humate solution to solution 1, mechanically stir for 15 min, and let stand for 30 min to obtain solution 2;

[0059] S4, add 10 ml of wood vinegar solution to solution 2, mix well, and stir for 15 minutes to obtain solution 3;

[0060] S5. The solution three is freeze-dried to obtain an industrial rare earth ammonium sulfate alkaline soil conditioner material.

[0061] Moreover, the concentration of the KOH solution is 5%.

[0062] Moreover, in the humic acid solution, the mass ratio of humic acid to water is 1:3.

[0063] Moreover, in the mineral source potassium humate solution, the mass ratio of mineral source potassium humate to water is 1:50.

[0064] Moreover, in the wood vinegar solution, the mass ratio of wood vinegar to water is 1:3.

[0065] Moreover, in step S5, during the freeze-drying process, the system is vacuumed to 2.6 MPa and the temperature is -50°C.

[0066] Experimental Section

[0067] The following materials (Table 1) were used to prepare soil conditioner raw materials. The soil conditioner raw materials were vacuumed to 2.6 MPa and freeze-dried at -50°C to prepare soil conditioner materials. Deionized water with a solid-liquid ratio of 1:4 was added for dissolution to prepare No. 1-6 conditioners for standby use. In the table, according to the mass ratio, the humic acid solution is humic acid: water = 1:3, the mineral potassium humate solution is mineral potassium humate: water = 1:50, the wood vinegar solution is wood vinegar: water = 1:3, and the microbial fertilizer is a compound microbial fertilizer (liquid) produced by Inner Mongolia Liangyi Biotechnology Co., Ltd., with an effective live bacteria count ≥ 200 million / mL.

[0068] Table 1 Different soil conditioner materials

[0069]

[0070] Experiment 1

[0071] The above-mentioned No. 1-6 improvers were tested for insoluble matter, organic matter, potassium, phosphorus, total nitrogen, mercury, arsenic, cadmium, chromium and lead. The results are shown in Table 2.

[0072] Table 2 Test results of improver

[0073]

[0074] As can be seen from Table 2, there are differences in the performance of improvers No. 1-6 in various test items. They all have good effects in terms of heavy metal safety. However, judging from the comprehensive situation of insoluble matter, organic matter, potassium, phosphorus, and total nitrogen, improver No. 5 has the best effect.

[0075] Experiment 2

[0076] 1. Seed treatment: Select large and full alfalfa seeds, soak them in distilled water at 30℃-40℃ for 4-6 hours. After soaking, rinse the seeds and rinse their surface with filter paper for later use.

[0077] 2. Soil treatment: Use saline-alkali soil as the test soil. Allow the soil to air dry naturally and pass through a 2mm sieve. Before planting, use a spray bottle to wet the sieved soil and stir it evenly to make the soil moist. Use indoor potted plants (diameter 6.5cm×6.5cm, height 6.5cm) to plant alfalfa. Fill each pot with an equal amount of treated soil and apply 1mL of the above-mentioned No. 1-6 soil conditioner. At the same time, set up a control group (pure saline-alkali soil, without any soil conditioner) and leave it for 3-5 days.

[0078] 3. Alfalfa planting: sow alfalfa seeds, cover the seeds with 1-1.5 cm of original soil, then spray an appropriate amount of water every day and wait for the alfalfa seeds to germinate. Each group conducted three repeated experiments, and recorded the germination rates at 7 and 14 days, and the root length of the seedlings at 10 days of growth. The results are shown in Table 3.

[0079] Table 3 Alfalfa growth

[0080]

[0081] From Table 3, we can know that No. 4 has more microbial fertilizer added than No. 5, but its germination rate is worse than that of No. 5. In the potted plants with No. 1, 2 and 4 improvers, it was found that after adding microbial fertilizer, the soil became moldy, which may affect the germination of plants.

[0082] Improver No. 6 contains more high-grade rare earth ammonium sulfate than the control group, and the germination rate is also significantly improved compared with the control group, indicating that the intermediate product high-grade rare earth ammonium sulfate prepared by the present invention also has a certain promoting effect on plant growth.

[0083] In general, whether on the 7th day or the 14th day, the alfalfa seed germination rate was the highest in the alfalfa potted plants applied with the No. 5 improver, with a germination rate of 85.7% on the 7th day and 90.4% on the 14th day; on the 10th day, the alfalfa seedlings had the best root length growth in the alfalfa potted plants applied with the No. 5 improver, and the root length could reach 4.45 cm, which proved that the superior rare earth ammonium sulfate prepared by the present invention can effectively promote plant growth after being mixed with humic acid solution, mineral potassium humate solution and wood vinegar solution in appropriate proportions.

[0084] The growth of alfalfa was recorded by photographs on the 7th, 14th and 21st days. Figure 1 In the figure, columns (a), (b), (c), (d), (e), (f), and (g) respectively show the growth of potted seedlings treated with Amendment No. 3, Amendment No. 4, Amendment No. 6, Amendment No. 5, Control Group, Amendment No. 1, and Amendment No. 2. From top to bottom, they are the records of the 7th, 14th, and 21st days. It can be seen from the figure that the alfalfa in the potted plant in group (d) has the best germination and the best seedling growth.

[0085] Experiment 3

[0086] One month after the alfalfa in Experiment 2 was planted, the soil pH and conductivity in each group of potted plants were measured. The results are shown in Table 4.

[0087] Table 4 Comparison of soil before and after improvement

[0088]

[0089] As can be seen from Table 4, the pH value of the soil in the control group was 8.83, which was alkaline. After being improved with amendments No. 1 to No. 6, the pH value of the soil decreased. Among them, the effect of applying amendment No. 5 was the most significant, reducing the soil pH value to 7.45, which was close to neutral.

[0090] The conductivity of the soil in the control group was 1430 us / cm, indicating that the content of soluble salt in the soil was high. After improvement with improvers No. 1 to No. 6, the effect of applying improver No. 5 was the most significant, reducing the soil conductivity to 1023 us / cm, and the reduction of soluble salt was the most obvious.

[0091] The alfalfa seedlings in the control group and the potted plants of the No. 5 amendment were removed and their root growth was recorded. The results are shown in Figure 2 As can be seen from the figure, the root growth of alfalfa seedlings in potted plants with No. 5 improver is significantly improved compared with that in the control group. The No. 5 improver of the present invention only needs to be added once during planting, and the pH value of the soil can reach neutral after one month of planting alfalfa. The effect of treating saline-alkali soil is significant, and the application prospect is broad.

[0092] Experiment 4

[0093] 1. Seed treatment: Select large and full alfalfa seeds, soak them in distilled water at 30℃-40℃ for 4-6 hours. After soaking, rinse the seeds and rinse their surface with filter paper for later use.

[0094] 2. Soil treatment: Use saline-alkali soil as the test soil. Allow the soil to air dry naturally and pass through a 2mm sieve. Before planting, use a spray bottle to wet the sieved soil and stir it evenly to make the soil moist. Use indoor potted plants (diameter 6.5cm×6.5cm, height 6.5cm) to plant alfalfa. Fill each pot with an equal amount of treated soil and apply 0.5ml, 1ml, 1.5ml, 2ml, and 2.5ml of the above-mentioned No. 5 soil conditioner respectively. At the same time, set up a control group (pure saline-alkali soil, without any soil conditioner) and leave it for 3-5 days.

[0095] 3. Alfalfa planting: Sow 20 alfalfa seeds in each pot, cover the seeds with 1-1.5 cm of original soil, then spray an appropriate amount of water every day and wait for the alfalfa seeds to germinate. Repeat the experiment three times for each group, record the germination rate on the 1st to 7th day, and record the root length of the seedlings after 10 days of growth. The results are shown in Table 5.

[0096] Table 5 Effects of different addition amounts of soil conditioners on alfalfa

[0097]

[0098] As can be seen from Table 5, with the increase in the amount of No. 5 improver added, the germination rate and the root length after 10 days first increased and then decreased. For the potted plants of 20 alfalfa seeds, the best effect was achieved when the amount of No. 5 improver added was 1 ml.

Claims

1. A method for preparing an industrial rare earth ammonium sulfate alkaline soil conditioner, characterized in that: The steps include: S1. Take the waste liquid of ammonium sulfate from rare earth smelting, add KOH solution thereto, stir for 10-20 minutes, let stand for 15-25 minutes, take the supernatant, and obtain the superior rare earth ammonium sulfate material; the concentration of the KOH solution is 4%-6%; S2. Add 15-25 ml of humic acid solution to 200 ml of high-grade rare earth ammonium sulfate material, stir mechanically for 10-20 min, and let stand for 25-35 min to obtain solution 1; S3, add 45-55 ml of mineral potassium humate solution to solution 1, mechanically stir for 10-20 min, and let stand for 25-35 min to obtain solution 2; S4, add 8-12 ml of wood vinegar solution to solution 2, mix well, and stir for 10-20 minutes to obtain solution 3; S5. The solution three is freeze-dried to obtain an industrial rare earth ammonium sulfate alkaline soil conditioner material.

2. The method for preparing an industrial rare earth ammonium sulfate alkaline soil conditioner according to claim 1, characterized in that: The steps include: S1. Take the waste liquid of ammonium sulfate from rare earth smelting, add KOH solution thereto, stir for 15 minutes, let stand for 20 minutes, take the supernatant, and obtain the superior rare earth ammonium sulfate material; S2. Add 20 ml of humic acid solution to 200 ml of high-grade rare earth ammonium sulfate material, stir mechanically for 15 min, and let stand for 30 min to obtain solution 1; S3, add 50 ml of mineral potassium humate solution to solution 1, mechanically stir for 15 min, and let stand for 30 min to obtain solution 2; S4, add 10 ml of wood vinegar solution to solution 2, mix well, and stir for 15 minutes to obtain solution 3; S5. The solution three is freeze-dried to obtain an industrial rare earth ammonium sulfate alkaline soil conditioner material.

3. The method for preparing an industrial rare earth ammonium sulfate alkaline soil conditioner according to claim 1, characterized in that: In the humic acid solution, the mass ratio of humic acid to water is 1:

3.

4. The method for preparing an industrial rare earth ammonium sulfate alkaline soil conditioner according to claim 1, characterized in that: In the mineral source potassium humate solution, the mass ratio of mineral source potassium humate to water is 1:

50.

5. The method for preparing an industrial rare earth ammonium sulfate alkaline soil conditioner according to claim 1, characterized in that: In the wood vinegar solution, the weight ratio of wood vinegar to water is 1:

3.

6. The method for preparing an industrial rare earth ammonium sulfate alkaline soil conditioner according to claim 1, characterized in that: In step S5, during the freeze-drying process, the system is vacuumed to 2.6 MPa and the temperature is -40°C to -60°C.

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