Green resourceful treatment method for rare earth ammonium sulfate waste liquid

Abstract

The invention provides a green resourceful treatment method for rare earth ammonium sulfate waste liquid, and relates to the technical field of wastewater treatment.The green resourceful treatment method comprises the following steps that S1, a fly ash sample is dried to constant weight; s2, pre-grinding lamellar KOH to 200 meshes, and drying the lamellar KOH to constant weight to obtain KOH powder; s3, mixing KOH powder with fly ash according to a mass ratio of 2: 3, and carrying out dry modification treatment on the fly ash by using KOH to obtain a KOH-fly ash composite material; s4, the KOH-fly ash composite material is dissolved in deionized water, and a KOH modified fly ash material is obtained; s5, adding 10 mL of the KOH modified fly ash material into 200 mL of the rare earth ammonium sulfate waste liquid, stirring, and standing; the KOH modified fly ash material is added into the rare earth ammonium sulfate waste liquid for the first time, the cost of directly treating ammonia nitrogen and heavy metal in the waste liquid is avoided, the process is simple, and a new utilization way of the rare earth ammonium sulfate waste liquid is provided.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, in particular to a method for green resource treatment of rare earth ammonium sulfate waste liquid. Background Art

[0002] The ammonia nitrogen wastewater recovered and treated in rare earth smelting production mainly comes from the ammonium bicarbonate precipitation of rare earth sulfate water leaching solution or the ammonia soap P507 transformation process. The effluent water contains iron (Fe 2+ ), mercury (Hg 2+ ), cadmium (Cd 2+ ), lead (Pb 2+ ), copper (Cu 2+ ), chromium (Cr 6+ )、Zn(Zn 2+ ), arsenic (As 3+ )、Rare earth(R 3+ ), sodium (Na + ), ammonium ion (NH4 + ), fluorine (F - ), chlorine (Cl - ), sulfate (SO4 2- ), sulfur (S 2- ), hydroxide (OH - ), carbonate (CO3 2- ), phosphate (PO4 3- ) and other salt substances. Among them, the components such as ammonia, nitrogen, phosphorus and sulfur in the wastewater not only cause eutrophication of water bodies, but are also essential nutrients for soil and plants and one of the raw materials for synthesizing urea. In addition, the trace rare earth lanthanum, cerium, praseodymium, neodymium, etc. in the wastewater can be absorbed and utilized by plants. However, arsenic (As 3+ ), mercury (Hg 2+ ), lead (Pb 2+ ), cadmium (Cd 2+ ) and chromium (Cr 6+ ), carbonate ions, etc. on soil and plants, which directly restricts their resource utilization.

[0003] Before rare earth ammonium sulfate waste liquid is directly discharged into the environment, the removal of conventional ammonia nitrogen, heavy metals and other harmful ions consumes a lot of manpower, material resources and financial resources. If the goal of resource utilization of rare earth ammonium sulfate waste liquid can be achieved, it will not only avoid the waste of resources but also save economic costs. The core link is how to achieve the "harm removal and efficiency enhancement treatment" of rare earth ammonium sulfate waste liquid.

[0004] The formation of saline-alkali soil is related to many factors such as geographical environment, climatic conditions, and hydrological conditions. This type of soil usually contains high salt and alkali content, resulting in poor soil structure and poor permeability, and is prone to osmotic stress and ion poisoning to plants. In such a soil environment, crop growth is often inhibited, and yield and quality are also affected. Soluble potassium in the soil has a positive effect on improving the physical properties of saline-alkali soil. 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.

[0005] In saline-alkali soils, crops have a more urgent need for potassium because potassium helps improve crop resistance, especially the ability to resist salt stress and alkali stress. By absorbing soluble potassium, crops can better regulate the ion balance and osmotic pressure in cells, thereby alleviating the adverse effects of saline-alkali stress on growth and yield.

[0006] Based on the above technical problems, a new method for "detoxification and efficiency enhancement" of rare earth ammonium sulfate waste liquid is urgently needed, which can not only avoid the direct treatment cost of rare earth ammonium sulfate waste liquid, but also enhance its advantages in the resource utilization of saline-alkali soil. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a method for green resource treatment of rare earth ammonium sulfate waste liquid, comprising the following steps: S1. Place the fly ash sample in a drying oven at a temperature of 105°C-110°C and dry it to constant weight; S2, pre-grind the lamellar KOH to 200 mesh, and dry it in a drying oven at 70°C-90°C to constant weight to obtain KOH powder; S3, mixing KOH powder and fly ash in a mass ratio of 2:1, and performing dry modification treatment on the fly ash using KOH for 30 minutes to obtain a KOH-fly ash composite material; The dry modification treatment is to add KOH powder and fly ash into a reaction container in proportion, and then heat and stir evenly for 30 minutes, and the heater temperature of the magnetic heating stirrer is 60°C; S4, dissolving the KOH-fly ash composite material prepared in step S3 in a certain amount of deionized water to prepare a dissolving solution, thereby obtaining a KOH-modified fly ash material; S5. Take 10 mL of the KOH-modified fly ash material obtained in step S4 and add it to 200 mL of rare earth ammonium sulfate waste liquid, and stir and allow to stand.

[0008] Furthermore, in step S1, the fly ash sample is placed in a drying oven at 105°C-110°C for 24 hours.

[0009] Furthermore, in step S2, the lamellar KOH is pre-ground to 200 mesh and dried in a drying oven at 70° C.-90° C. for 24 hours.

[0010] Furthermore, in step S4, after the KOH-fly ash composite material is dissolved in deionized water, the mass fraction of the KOH-fly ash composite material is 4%.

[0011] Furthermore, in step S5, the stirring time is 15 minutes and the standing time is 20 minutes.

[0012] Compared with the prior art, the present invention has the following advantages: 1. The present invention proposes for the first time to add KOH to modify fly ash material in rare earth ammonium sulfate waste liquid, thereby avoiding the cost of treating ammonia nitrogen and heavy metals in rare earth ammonium sulfate waste liquid, and the process is simple, providing a new way to utilize rare earth ammonium sulfate waste liquid.

[0013] 2. The present invention not only adjusts the pH of rare earth ammonium sulfate waste liquid, retains the ammonia nitrogen rare earth components in the solution, but also reduces the heavy metal ions that are toxic and harmful to the soil, and at the same time introduces potassium ions (an element urgently needed by saline-alkali soil and plants), thereby improving the application value of rare earth ammonium sulfate waste liquid in saline-alkali soil.

[0014] 3. The present invention can effectively react with heavy metal ions (such as arsenic, mercury, lead, cadmium, chromium, etc.) in rare earth ammonium sulfate waste liquid to form insoluble precipitates through the introduction of KOH-modified fly ash materials, thereby achieving effective removal of these harmful ions; KOH-modified fly ash materials can also react with other harmful substances (such as carbonate, etc.) in the waste liquid to reduce their negative cumulative effects on soil and plants; the water quality of the treated rare earth ammonium sulfate waste liquid is significantly improved, providing a strong guarantee for subsequent resource utilization; at the same time, potassium ions and other nutrients are retained in the purified water body, which can be used to improve the saline-alkali soil environment. Potassium ions can be exchanged with other cations on soil colloids, thereby changing the charge characteristics and aggregate stability of soil colloids, such as improving Na +The leaching effect of ammonium sulfate wastewater can improve the aeration and water permeability of the soil, and provide a better soil environment for the root growth of crops. At the same time, potassium is one of the nutrients necessary for plant growth and is involved in a variety of physiological and biochemical processes, such as photosynthesis, material transport, and cell osmotic regulation. Moreover, the rare earth elements (such as lanthanum, cerium, praseodymium, neodymium, etc.) present in rare earth ammonium sulfate wastewater can be absorbed and utilized by plants to promote the growth and development of crops. These rare earth elements also have the ability to improve crop resistance to stress (such as salt stress and alkali stress), which helps crops maintain higher yields and quality in saline-alkali soil environments.

[0015] 4. The method of the present invention avoids the problem of possible environmental pollution caused by direct discharge of rare earth ammonium sulfate waste liquid into the environment, thereby protecting the ecological environment and human health; by resource-based utilization of useful components in the rare earth ammonium sulfate waste liquid, it also helps to achieve resource recycling and sustainable development.

[0016] 5. The method of the present invention not only realizes the resource utilization of rare earth ammonium sulfate waste liquid, but also reduces the processing cost and improves the economic benefit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The scanning electron micrographs of No. 0 and No. 4 precipitates; Figure 2 This is the SEM energy spectrum analysis diagram of No. 0 and No. 4 precipitation; Figure 3 This is a comparison of the growth of alfalfa potted experiments; Figure 4 This is a comparison of the growth of alfalfa in hydroponic experiments. DETAILED DESCRIPTION

[0018] Example 1 A method for green resource treatment of rare earth ammonium sulfate waste liquid comprises the following steps: S1. Place the fly ash sample in a drying oven at 105°C and dry it to constant weight; S2, pre-grinding the lamellar KOH to 200 mesh, and drying in a drying oven at 70° C. to constant weight to obtain KOH powder; S3, mixing KOH powder and fly ash in a mass ratio of 2:1, and performing dry modification treatment on the fly ash using KOH for 30 minutes to obtain a KOH-fly ash composite material; The dry modification treatment is to add KOH powder and fly ash into a reaction container in proportion, and then heat and stir evenly for 30 minutes, and the heater temperature of the magnetic heating stirrer is 60°C; S4, dissolving the KOH-fly ash composite material prepared in step S3 in a certain amount of deionized water to prepare a dissolving solution, thereby obtaining a KOH-modified fly ash material; S5. Take 10 mL of the KOH-modified fly ash material obtained in step S4 and add it to 200 mL of rare earth ammonium sulfate waste liquid, and stir and allow to stand.

[0019] Moreover, in the step S1, the fly ash sample is placed in a drying oven at 105° C. for 24 hours.

[0020] Furthermore, in the step S2, the lamellar KOH is pre-ground to 200 meshes and dried in a drying oven at 70° C. for 24 hours.

[0021] Moreover, in the step S4, after the KOH-fly ash composite material is dissolved in deionized water, the mass fraction of the KOH-fly ash composite material is 4%.

[0022] Moreover, in step S5, the stirring time is 15 minutes and the standing time is 20 minutes.

[0023] Example 2 A method for green resource treatment of rare earth ammonium sulfate waste liquid comprises the following steps: S1. Place the fly ash sample in a drying oven at 110°C and dry it to constant weight; S2, pre-grinding the lamellar KOH to 200 mesh, and drying in a drying oven at 90° C. to constant weight to obtain KOH powder; S3, mixing KOH powder and fly ash in a mass ratio of 2:1, and performing dry modification treatment on the fly ash using KOH for 30 minutes to obtain a KOH-fly ash composite material; The dry modification treatment is to add KOH powder and fly ash into a reaction container in proportion, and then heat and stir evenly for 30 minutes, and the heater temperature of the magnetic heating stirrer is 60°C; S4, dissolving the KOH-fly ash composite material prepared in step S3 in a certain amount of deionized water to prepare a dissolving solution, thereby obtaining a KOH-modified fly ash material; S5. Take 10 mL of the KOH-modified fly ash material obtained in step S4 and add it to 200 mL of rare earth ammonium sulfate waste liquid, and stir and allow to stand.

[0024] Moreover, in the step S1, the fly ash sample is placed in a drying oven at 110° C. for 24 hours.

[0025] Furthermore, in the step S2, the lamellar KOH is pre-ground to 200 mesh and dried in a drying oven at 90° C. for 24 hours.

[0026] Moreover, in the step S4, after the KOH-fly ash composite material is dissolved in deionized water, the mass fraction of the KOH-fly ash composite material is 4%.

[0027] Moreover, in step S5, the stirring time is 15 minutes and the standing time is 20 minutes.

[0028] Example 3 A method for green resource treatment of rare earth ammonium sulfate waste liquid comprises the following steps: S1. Place the fly ash sample in a drying oven at 108°C and dry it to constant weight; S2, pre-grinding the lamellar KOH to 200 mesh, and drying in a drying oven at 80° C. to constant weight to obtain KOH powder; S3, mixing KOH powder and fly ash in a mass ratio of 2:1, and performing dry modification treatment on the fly ash using KOH for 30 minutes to obtain a KOH-fly ash composite material; The dry modification treatment is to add KOH powder and fly ash into a reaction container in proportion, and then heat and stir evenly for 30 minutes, and the heater temperature of the magnetic heating stirrer is 60°C; S4, dissolving the KOH-fly ash composite material prepared in step S3 in a certain amount of deionized water to prepare a dissolving solution, thereby obtaining a KOH-modified fly ash material; S5. Take 10 mL of the KOH-modified fly ash material obtained in step S4 and add it to 200 mL of rare earth ammonium sulfate waste liquid, and stir and allow to stand.

[0029] Moreover, in the step S1, the fly ash sample is placed in a drying oven at 108° C. for 24 hours.

[0030] Furthermore, in the step S2, the lamellar KOH is pre-ground to 200 mesh and dried in a drying oven at 80° C. for 24 hours.

[0031] Moreover, in the step S4, after the KOH-fly ash composite material is dissolved in deionized water, the mass fraction of the KOH-fly ash composite material is 4%.

[0032] Moreover, in step S5, the stirring time is 15 minutes and the standing time is 20 minutes.

[0033] Experimental Section

[0034] Experiment 1 1. The fly ash sample was placed in a drying oven at a temperature of 105°C-110°C and dried to constant weight (24 hours). The lamellar KOH was pre-grinded to 200 mesh and dried in a drying oven at 70-90°C to constant weight (24 hours). The dried KOH was mixed with fly ash in a mass ratio of 1:1 (sample No. 1), 1:2 (sample No. 2), 1:3 (sample No. 3), 2:1 (sample No. 4 of the present invention), and 2:3 (sample No. 5). The mixture was evenly stirred on a magnetic heating stirrer (heater temperature 60°C) for 30 minutes to obtain a KOH-fly ash composite material.

[0035] 2. The KOH-fly ash composite material prepared above was dissolved in a certain amount of deionized water so that the mass fraction of the composite material was 4%, and a dissolving solution was prepared. The obtained sample was the KOH-modified fly ash material.

[0036] 3. Add 10 mL of KOH-modified fly ash material into 200 mL of rare earth ammonium sulfate waste liquid, stir for 15 min, let stand for 20 min, retain 150 mL of the supernatant for characterization analysis, and dry the precipitate in a 40°C oven for 24 h.

[0037] 1. Supernatant composition test The supernatant and precipitate obtained in step 3 were retained respectively, and the supernatant of the rare earth ammonium sulfate waste liquid after being treated with KOH-modified fly ash material was tested for pH, conductivity, arsenic (As 3+ ), mercury (Hg 2+ ), lead (Pb 2+ ), cadmium (Cd 2+ ), chromium (Cr 6+ ) ion and other tests. The test results are shown in Table 1 and Table 2.

[0038] Table 1 Test results of supernatant (1)

[0039] Table 2 Test results of supernatant (2)

[0040] It can be seen from Table 1 and Table 2 that by adopting the technical scheme of the present invention, TIC (total carbon), TN (total nitrogen) and K in the supernatant are increased compared with other groups, the pH value tends to be neutral, the beneficial components ammonia nitrogen, trace rare earth elements lanthanum, cerium, praseodymium, neodymium, etc. are retained to a large extent, and the harmful components arsenic, mercury, lead, chromium, cadmium, etc. are effectively removed, which meets the requirements for the improvement of saline-alkali soil.

[0041] 2. Precipitation electron microscope scanning The precipitate of No. 0 (stock solution) and the precipitate of No. 4 (the present invention) were scanned by electron microscope, and the results were as follows: Figure 1 As shown, from Figure 1 It can be seen that the precipitation structure of the rare earth ammonium sulfate waste liquid produced after treatment with KOH-modified fly ash material is dense and uniform, and heavy metals are effectively removed.

[0042] 3. Precipitation spectrum test The precipitate of No. 0 (stock solution) and the precipitate of No. 4 (the present invention) were subjected to energy spectrum test. The results of SEM energy spectrum analysis are as follows: Figure 2 As shown, from Figure 2 It can be further confirmed that fly ash material modified by KOH can effectively remove heavy metals in rare earth ammonium sulfate waste liquid, indicating that the present invention realizes the resource treatment of rare earth ammonium sulfate waste liquid.

[0043] Experiment 2 Pot experiment: There are two ways to cultivate alfalfa in pots; Group 1: After planting alfalfa seeds, tap water was used for irrigation on the first day, and 5 mL of the No. 4 supernatant prepared in Experiment 1 was added on the third day. Tap water was used for irrigation on the fifth and seventh days. Group 2: Normal irrigation with tap water only on days 1, 3, 5, and 7 after planting; Results Figure 3 , Figure 3 (a), (b), (c), and (d) are the growth conditions of the first group of alfalfa on the 1st, 3rd, 5th, and 7th days respectively; (i), (j), (k), and (l) are the growth conditions of the second group of alfalfa on the 1st, 3rd, 5th, and 7th days respectively. It can be seen from the figure that after watering with the treatment solution of the present invention, the alfalfa began to germinate from the third day, and on the seventh day, more seeds germinated, and the germination rate was higher; while no germination was observed in the alfalfa watered with tap water within seven days, which proves that the treatment solution prepared by the method for green resource treatment of rare earth ammonium sulfate waste liquid of the present invention can effectively promote seed germination and growth.

[0044] Experiment 3 Hydroponic experiment: There are two ways to cultivate alfalfa hydroponically. Group A uses a 1:200 culture solution of No. 4 stock solution and tap water (yellowish in color), and Group B uses tap water as the culture solution. Figure 4 This is a comparison of the roots of alfalfa seeds one week later. It can be seen from the figure that after adding the culture solution with a ratio of 1:200 of No. 4 stock solution and tap water, the roots of alfalfa seeds grew better.

Claims

1. A method for green resource treatment of rare earth ammonium sulfate waste liquid, characterized in that: The steps include: S1. Place the fly ash sample in a drying oven at a temperature of 105°C-110°C and dry it to constant weight; S2, pre-grind the lamellar KOH to 200 mesh, and dry it in a drying oven at 70°C-90°C to constant weight to obtain KOH powder; S3, mixing KOH powder and fly ash in a mass ratio of 2:1, and performing dry modification treatment on the fly ash using KOH for 30 minutes to obtain a KOH-fly ash composite material; S4, dissolving the KOH-fly ash composite material prepared in step S3 in deionized water to prepare a dissolving solution, thereby obtaining a KOH-modified fly ash material; S5. Take 10 mL of the KOH-modified fly ash material obtained in step S4 and add it to 200 mL of rare earth ammonium sulfate waste liquid, and stir and allow to stand.

2. The method for green resource treatment of rare earth ammonium sulfate waste liquid according to claim 1, characterized in that: In the step S1, the fly ash sample is placed in a drying oven at 105° C.-110° C. and dried for 24 hours.

3. The method for green resource treatment of rare earth ammonium sulfate waste liquid according to claim 1, characterized in that: In the step S2, the lamellar KOH is pre-ground to 200 mesh and dried in a drying oven at 70° C.-90° C. for 24 hours.

4. The method for green resource treatment of rare earth ammonium sulfate waste liquid according to claim 1, characterized in that: The dry modification treatment is to add KOH powder and fly ash into a reaction container in proportion, and then heat and stir evenly for 30 minutes, and the heater temperature of the magnetic heating stirrer is 60°C.

5. The method for green resource treatment of rare earth ammonium sulfate waste liquid according to claim 1, characterized in that: In the step S4, after the KOH-fly ash composite material is dissolved in deionized water, the mass fraction of the KOH-fly ash composite material is 4%.

6. The method for green resource treatment of rare earth ammonium sulfate waste liquid according to claim 1, characterized in that: In step S5, the stirring time is 15 minutes and the standing time is 20 minutes.

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