A method for the synergistic harmless treatment of phosphogypsum and barium slag

Abstract

This invention relates to the field of solid waste treatment technology, specifically to a method for the synergistic harmless treatment of phosphogypsum and barium slag. The method includes: co-grinding phosphogypsum, biomass, minerals, and peroxides to obtain a composite phosphogypsum raw material; adding phosphate-solubilizing fungi and performing curing and washing treatments to obtain filtrate one and filter residue one; adding an adsorbent to filtrate one for adsorption treatment, followed by solid-liquid separation to obtain filtrate two and the adsorbent after adsorption treatment; mixing filter residue one with barium slag to obtain a mixture, adding filtrate two, and allowing it to stand for aging to obtain a phosphogypsum-barium slag composite. This method effectively fixes acid-soluble barium in the barium slag and removes harmful pollutants such as soluble phosphorus, eutectic phosphorus, and fluorides from the phosphogypsum, while minimizing the generation of byproducts other than the phosphogypsum-barium slag composite, providing a greener and more environmentally friendly method for the synergistic harmless treatment of phosphogypsum and barium slag.

Description

Technical Field

[0001] This invention relates to the field of solid waste treatment technology, specifically to a method for the synergistic harmless treatment of phosphogypsum and barium slag. Background Technology

[0002] Phosphogypsum is an acidic industrial waste produced during the wet process of producing phosphoric acid from phosphate rock. Its main component is CaSO4·2H2O. Phosphogypsum contains harmful pollutants such as soluble phosphorus, eutectic phosphorus, and fluorides. Large quantities of phosphogypsum are stockpiled in slag dumps, which not only wastes land resources but also poses a serious threat to the safety of surrounding soil and water resources.

[0003] Barium slag is an industrial residue filtered out during the production of barium salts from barite. It is strongly alkaline and mainly contains acid-soluble and water-soluble barium. Barium in barium slag is a heavy metal element harmful to human health; inhalation or ingestion can cause acute barium poisoning. Barium slag is classified as hazardous solid waste in the "National Hazardous Waste List," and the fixation of barium ions is a crucial step in its resource utilization.

[0004] Chinese patent document CN113996639A discloses a method for the synergistic harmless treatment of barium slag and phosphogypsum. This method involves mixing and stirring barium slag and phosphogypsum in a specific ratio, followed by aging. However, this method does not address the harmful pollutants inherent in phosphogypsum, such as soluble phosphorus, eutectic phosphorus, and fluorides. Furthermore, it is less effective at treating acid-soluble barium in the barium slag, which has certain implications for subsequent storage or resource recovery. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of existing methods for the synergistic harmless treatment of phosphogypsum and barium slag, which have poor treatment effect on acid-soluble barium in barium slag and cannot remove harmful pollutants in phosphogypsum. Thus, a method for the synergistic harmless treatment of phosphogypsum and barium slag is provided to solve the above problems.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for the synergistic harmless treatment of phosphogypsum and barium slag includes:

[0008] A composite phosphogypsum raw material is obtained by co-grinding phosphogypsum, biomass, minerals and peroxides. Phosphate-solubilizing fungi are added and the material is cured and washed with water to obtain filtrate one and filter residue one.

[0009] An adsorbent was added to filtrate one for adsorption treatment, and solid-liquid separation was performed to obtain filtrate two and the adsorbent after adsorption treatment;

[0010] The filter residue 1 and barium residue were mixed to obtain a mixture, and then filtrate 2 was added and allowed to stand for aging to obtain a phosphogypsum-barium residue composite.

[0011] The adsorbent is a modified coal gangue composite material; the process of obtaining the modified coal gangue composite material is as follows: coal gangue, calcite and montmorillonite are ground and calcined to obtain the composite material, the composite material is soaked in chitosan solution and freeze-dried, the freeze-dried composite material is coupled in a mixture of solvent, cerium ammonium nitrate, nitric acid and glycidyl methacrylate under an inert atmosphere, and finally organic solvent and amino modifying agent are added for modification treatment.

[0012] The mass ratio of the coal gangue, calcite, and montmorillonite is (5-10):1:1;

[0013] And / or, the mass ratio of the composite material, solvent, cerium ammonium nitrate, nitric acid and glycidyl methacrylate is 5:(100-200):1:(0.1-0.5):(1-5);

[0014] And / or, in the modification treatment, the mass ratio of the composite material, the organic solvent and the amino modifying agent is 1:(10-50):(1-5);

[0015] And / or, the solvent is water;

[0016] And / or, the organic solvent is N,N-dimethylformamide;

[0017] And / or, the amino-modifying agent is aminoguanidine hydrochloride.

[0018] The grinding process is preceded by washing, drying, and crushing.

[0019] And / or, the calcination temperature is 300-600℃, and the calcination time is 3-5h;

[0020] And / or, the concentration of the chitosan solution is 1-3 wt%;

[0021] And / or, the concentration of the nitric acid is 50-70 wt%;

[0022] And / or, the soaking treatment lasts for 0.5-1 hour;

[0023] And / or, the inert atmosphere is a nitrogen atmosphere;

[0024] And / or, the duration of the coupling reaction is 2-5 hours; the temperature of the coupling reaction is room temperature;

[0025] And / or, the temperature of the modification treatment is 100-120℃, and the duration of the modification treatment is 1-3h.

[0026] The biomass is at least one of straw, sawdust, and peanut shells;

[0027] And / or, the mineral is hydrotalcite and / or palygorskite;

[0028] And / or, the peroxide is calcium peroxide and / or sodium peroxide;

[0029] And / or, the phosphorus-solubilizing fungus is at least one of Penicillium, Aspergillus niger, lactic acid bacteria, and acetic acid bacteria;

[0030] And / or, the mass ratio of the phosphogypsum, biomass, minerals and peroxide is (10-20):1:0.1:0.1;

[0031] And / or, the mass ratio of the composite phosphogypsum raw material to phosphate-solubilizing fungi is 100:(1-5).

[0032] The phosphate-solubilizing fungi are a mixture of Penicillium, Aspergillus niger, lactic acid bacteria, and acetic acid bacteria.

[0033] The percentages of Penicillium, Aspergillus niger, Lactic acid bacteria, and Acetic acid bacteria are 1:1:1:1.

[0034] In the water washing process, the mass ratio of the cured composite phosphogypsum raw material to water is 1:(2-5);

[0035] And / or, in the adsorption treatment, the mass ratio of filtrate to adsorbent is 100:(1-5);

[0036] And / or, the mass ratio of the filter residue to the barium residue is (1-5):20;

[0037] And / or, the mass ratio of the filtrate to the mixture is (1-5):10.

[0038] The duration of the maintenance treatment is 7-14 days;

[0039] And / or, the duration of the static aging is 1-3 days;

[0040] And / or, the duration of the adsorption treatment is 30 min;

[0041] And / or, the phosphogypsum, biomass, minerals and peroxides are further subjected to sieving and drying treatment before co-grinding;

[0042] And / or, the water washing process is as follows: first, the cured composite phosphogypsum raw material is mixed with water and allowed to stand for a period of time, and finally, solid-liquid separation is performed.

[0043] The sieve used in the sieving process has a mesh size of 20.

[0044] And / or, the drying temperature is 40°C;

[0045] And / or, the mixing time is 0.5-2 hours;

[0046] And / or, the settling time is 1-5 hours.

[0047] The present invention also provides a phosphogypsum-barium slag composite, which is prepared by the above-mentioned method of synergistic harmless treatment of phosphogypsum and barium slag.

[0048] In this invention, both the co-grinding treatment and the grinding treatment are ball milling, the ball-to-material ratio in the ball milling is (10-20):1, the ball milling speed is 200-300 rpm / min, and the ball milling time is 10-30 min.

[0049] The technical solution of this invention has the following advantages:

[0050] 1. A method for the synergistic harmless treatment of phosphogypsum and barium slag, comprising: co-grinding phosphogypsum, biomass, minerals, and peroxides to obtain a composite phosphogypsum raw material; adding phosphate-solubilizing fungi and performing curing and washing treatment to obtain filtrate one and filter residue one; adding an adsorbent to filtrate one for adsorption treatment, and separating the solid and liquid to obtain filtrate two and the adsorbent after adsorption treatment; mixing filter residue one with barium slag to obtain a mixture, adding filtrate two, and allowing it to stand for aging to obtain a phosphogypsum-barium slag composite. This method introduces phosphate-solubilizing fungi commonly used for slow-release phosphorus in soil to secrete citric acid, oxalic acid, lactic acid, and acetic acid to convert insoluble phosphorus and eutectic phosphorus in phosphogypsum into soluble phosphorus. Subsequently, soluble phosphorus and soluble fluoride in the phosphogypsum are removed by washing, and phosphate and fluoride ions in the filtrate are adsorbed by an adsorbent to obtain a pure acidic filtrate. Finally, sulfate ions in the phosphogypsum are used to fix soluble barium ions in the barium slag, while the acidic filtrate is added to solidify the acid-soluble barium ions in the barium slag. This method treats phosphogypsum and barium slag harmlessly based on the properties of the substances produced in each step. The steps are interconnected. Under the premise that acid-soluble barium in the barium slag is effectively fixed and harmful pollutants such as soluble phosphorus, eutectic phosphorus, and fluorides in phosphogypsum are removed, the generation of by-products other than the phosphogypsum-barium slag complex is minimized as much as possible, which greatly improves the synergistic harmless treatment effect of phosphogypsum and barium slag and provides a greener and more environmentally friendly synergistic harmless treatment method for phosphogypsum and barium slag.

[0051] In addition, the addition of biomass in this method can not only provide nitrogen and carbon sources for microorganisms, but also increase the uniformity of mixing phosphogypsum and biomass; the addition of minerals can increase the uniformity of mixing phosphogypsum and biomass, and can also provide trace elements, which can activate microorganisms; peroxides can release oxygen slowly, provide oxygen for microorganisms, and can generate alkaline products, thereby neutralizing the acidity of phosphogypsum.

[0052] 2. In a method for the synergistic harmless treatment of phosphogypsum and barium slag according to the present invention, a modified coal gangue composite material is used to adsorb phosphate and fluoride ions in the filtrate. The modified coal gangue composite material is made from coal gangue, calcite, and montmorillonite. Through calcination modification, the composite material contains a large number of calcium and aluminum ions. Subsequently, it is treated with chitosan solution to increase the hydroxyl and amino functional groups of the composite material. The hydroxyl functional groups are beneficial to the subsequent coupling reaction, and the amino functional groups are beneficial to the subsequent adsorption reaction. Then, it is coupled with glycidyl methacrylate and modified with an amino-modifying reagent. The prepared modified coal gangue composite material has excellent adsorption and fixation effect on phosphate and fluoride ions in the filtrate. Attached Figure Description

[0053] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0054] Figure 1 This is a graph showing the effect of oscillation time on the adsorption of phosphate and fluoride ions by the modified coal gangue composite material in Example 1 of the present invention.

[0055] Figure 2 This is a graph showing the effect of pH on the adsorption of phosphate and fluoride ions by the modified coal gangue composite material in Example 1 of this invention.

[0056] Figure 3 This is a graph showing the effect of oscillation time on the adsorption of phosphate and fluoride ions by the modified coal gangue composite material in Example 4 of the present invention.

[0057] Figure 4 This is a graph showing the effect of pH on the adsorption of phosphate and fluoride ions by the modified coal gangue composite material in Example 4 of this invention. Detailed Implementation

[0058] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0059] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0060] Example 1

[0061] This embodiment provides a method for the synergistic harmless treatment of phosphogypsum and barium slag, including the following steps:

[0062] 1) Phosphogypsum, straw, hydrotalcite, and calcium peroxide that have passed through a 20-mesh sieve are dried at 40℃. Then, 100g of phosphogypsum, 10g of straw, and 1g of hydrotalcite are weighed and ball-milled for 30min. Then, 1g of calcium peroxide is added and ball-milled for 10min to obtain composite phosphogypsum raw material. The ball-to-material ratio in the ball mill is 10:1, and the ball milling speed is 300rpm / min. Then, phosphate-solubilizing fungi are sprayed on the mixture. The phosphate-solubilizing fungi are a mixture of Penicillium, Aspergillus niger, lactic acid bacteria, and acetic acid bacteria. The mass ratio of Penicillium, Aspergillus niger, lactic acid bacteria, and acetic acid bacteria is 1:1:1:1. The mass ratio of composite phosphogypsum raw material to phosphate-solubilizing fungi is 100:5. The mixture is cured for 7 days.

[0063] 2) Weigh 100g of the cured composite phosphogypsum raw material from step 1) and 200g of water, stir and mix at 200rpm / min for 0.5h, let stand for 2h, and then filter to obtain filtrate 1 and filter residue 1.

[0064] 3) Preparation of modified coal gangue composite material: Coal gangue, calcite, and montmorillonite were washed and dried, then crushed. Finally, 10g of coal gangue, 1g of calcite, and 1g of montmorillonite were weighed and ball-milled for 10min, with a ball-to-material ratio of 10:1 and a ball milling speed of 300rpm / min. The resulting composite material was calcined at 600℃ for 3h. 10g of the calcined composite material was weighed and soaked in 50mL of 1wt% chitosan solution for 1h, followed by freeze-drying. Then, 5g of the freeze-dried composite material, 100g of water, 1g of cerium ammonium nitrate, and 0.4g of 60wt% nitric acid were weighed and mixed and stirred for 10min under nitrogen protection. 5g of glycidyl methacrylate was added and coupled at room temperature for 3h, followed by washing and drying. 1g of the coupled composite material and 20g of... N,N-dimethylformamide and 2g of aminoguanidine hydrochloride were modified at 100℃ for 1h, filtered, washed and dried to obtain modified coal gangue composite material.

[0065] 4) Add the modified coal gangue composite material obtained in step 3) to the filtrate one obtained in step 2) and perform adsorption treatment for 30 min, wherein the mass ratio of filtrate one to modified coal gangue composite material is 100:1. Then filter to obtain filtrate two and the modified coal gangue composite material after adsorption treatment.

[0066] 5) Mix filter residue one and barium slag at a mass ratio of 1:10 to obtain a mixture, then add filtrate two, mix well, and let stand for aging for 1 day to obtain phosphogypsum barium slag composite, wherein the mass ratio of filtrate two to the mixture is 3:10.

[0067] The total phosphorus and soluble fluoride contents of phosphogypsum before and after the harmless treatment in the above embodiments were tested. The total phosphorus was tested by preparing a solution according to GB / T 23456-2009 phosphogypsum and then detecting it by ammonium molybdate spectrophotometry. The soluble fluoride was detected by ion-selective electrode method. After testing, the total phosphorus content decreased from 126.7 mg / L to 0.37 mg / L and the soluble fluoride content decreased from 67.56 mg / L to 0.43 mg / L after the harmless treatment.

[0068] In the above embodiments, the barium slag before and after harmless treatment was subjected to pH testing and toxicity leaching tests according to the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB5085.3-2007). The tests showed that after harmless treatment, the pH decreased from 12.29 to 7.54, and the barium ion concentration decreased from 1570 mg / L to 6.27 mg / L.

[0069] Example 2

[0070] This embodiment provides a method for the synergistic harmless treatment of phosphogypsum and barium slag, including the following steps:

[0071] 1) Dry phosphogypsum, sawdust, hydrotalcite, and calcium peroxide that have passed through a 20-mesh sieve at 40℃. Then weigh 100g of phosphogypsum, 10g of straw, and 1g of hydrotalcite and ball mill for 10min. Add 1g of calcium peroxide and ball mill for another 10min to obtain composite phosphogypsum raw material. The ball-to-material ratio in the ball mill is 10:1, and the ball milling speed is 200rpm / min. Then spray with phosphate-solubilizing fungi, which is a mixture of Penicillium, Aspergillus niger, lactic acid bacteria, and acetic acid bacteria. The mass ratio of Penicillium, Aspergillus niger, lactic acid bacteria, and acetic acid bacteria is 1:1:1:1. The mass ratio of composite phosphogypsum raw material to phosphate-solubilizing fungi is 100:1. Curing treatment for 7 days.

[0072] 2) Weigh 100g of the cured composite phosphogypsum raw material from step 1) and 200g of water, stir and mix at 200rpm / min for 0.5h, let stand for 1h, and then filter to obtain filtrate 1 and filter residue 1.

[0073] 3) Preparation of modified coal gangue composite material: Coal gangue, calcite, and montmorillonite were washed and dried, then crushed. Finally, 5g of coal gangue, 1g of calcite, and 1g of montmorillonite were weighed and ball-milled for 10min, with a ball-to-material ratio of 10:1 and a ball-milling speed of 200rpm / min. The resulting composite material was calcined at 300℃ for 3h. 10g of the calcined composite material was weighed and soaked in 50mL of 1wt% chitosan solution for 0.5h, followed by freeze-drying. Then, 5g of the freeze-dried composite material, 100g of water, 1g of cerium ammonium nitrate, and 0.1g of 50wt% nitric acid were weighed and mixed and stirred for 10min under nitrogen protection. 1g of glycidyl methacrylate was added and coupled at room temperature for 2h, followed by washing and drying. 1g of the coupled composite material and 10g of... N,N-dimethylformamide and 1g of aminoguanidine hydrochloride were modified at 100℃ for 1h, filtered, washed and dried to obtain modified coal gangue composite material.

[0074] 4) Add the modified coal gangue composite material obtained in step 3) to the filtrate one obtained in step 2) and perform adsorption treatment for 30 min, wherein the mass ratio of filtrate one to modified coal gangue composite material is 100:1. Then filter to obtain filtrate two and the modified coal gangue composite material after adsorption treatment.

[0075] 5) Mix filter residue one and barium slag at a mass ratio of 1:20 to obtain a mixture, then add filtrate two, mix well, and let stand for aging for 1 day to obtain phosphogypsum barium slag composite, wherein the mass ratio of filtrate two to the mixture is 1:10.

[0076] The total phosphorus and soluble fluoride contents of phosphogypsum before and after the harmless treatment in the above embodiments were tested. The total phosphorus was tested by preparing a solution according to GB / T 23456-2009 phosphogypsum and then detecting it by ammonium molybdate spectrophotometry. The soluble fluoride was detected by ion-selective electrode method. After testing, the total phosphorus content decreased from 131.9 mg / L to 0.49 mg / L and the soluble fluoride content decreased from 68.92 mg / L to 0.75 mg / L after the harmless treatment.

[0077] In the above embodiments, the barium slag before and after harmless treatment was subjected to pH testing and toxicity leaching tests according to the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB5085.3-2007). The tests showed that after harmless treatment, the pH decreased from 12.25 to 7.87, and the barium ion concentration decreased from 1567 mg / L to 9.34 mg / L.

[0078] Example 3

[0079] This embodiment provides a method for the synergistic harmless treatment of phosphogypsum and barium slag, including the following steps:

[0080] 1) Phosphogypsum, peanut shells, palygorskite, and sodium peroxide that have passed through a 20-mesh sieve are dried at 40℃. Then, 200g of phosphogypsum, 10g of straw, and 1g of hydrotalcite are weighed and ball-milled for 30min. Then, 1g of calcium peroxide is added and ball-milled for 10min to obtain composite phosphogypsum raw material. The ball-to-material ratio in the ball mill is 20:1, and the ball milling speed is 300rpm / min. Then, phosphate-solubilizing fungi are sprayed on the mixture. The phosphate-solubilizing fungi are a mixture of Penicillium, Aspergillus niger, lactic acid bacteria, and acetic acid bacteria. The mass ratio of Penicillium, Aspergillus niger, lactic acid bacteria, and acetic acid bacteria is 1:1:1:1. The mass ratio of composite phosphogypsum raw material to phosphate-solubilizing fungi is 100:5. The mixture is cured for 14 days.

[0081] 2) Weigh 100g of the cured composite phosphogypsum raw material from step 1) and 500g of water, stir and mix at 300rpm / min for 2 hours, let stand for 5 hours, and then filter to obtain filtrate 1 and filter residue 1.

[0082] 3) Preparation of modified coal gangue composite material: Coal gangue, calcite, and montmorillonite were washed and dried, then crushed. Finally, 10g of coal gangue, 1g of calcite, and 1g of montmorillonite were weighed and ball-milled for 10min, with a ball-to-material ratio of 20:1 and a ball milling speed of 300rpm / min. The resulting composite material was calcined at 600℃ for 5h. 10g of the calcined composite material was weighed and soaked in 50mL of 3wt% chitosan solution for 1h, followed by freeze-drying. Then, 5g of the freeze-dried composite material, 200g of water, 1g of cerium ammonium nitrate, and 0.5g of 70wt% nitric acid were weighed and mixed and stirred for 10min under nitrogen protection. 5g of glycidyl methacrylate was added and coupled at room temperature for 5h, followed by washing and drying. 1g of the coupled composite material and 50g of... N,N-dimethylformamide and 5g of aminoguanidine hydrochloride were modified at 120℃ for 3h, filtered, washed and dried to obtain modified coal gangue composite material.

[0083] 4) Add the modified coal gangue composite material obtained in step 3) to the filtrate one obtained in step 2) and perform adsorption treatment for 30 min, wherein the mass ratio of filtrate one to modified coal gangue composite material is 100:5. Then filter to obtain filtrate two and the modified coal gangue composite material after adsorption treatment.

[0084] 5) Mix filter residue one and barium slag at a mass ratio of 1:4 to obtain a mixture, then add filtrate two, mix well, and let stand for 3 days to obtain phosphogypsum barium slag composite, wherein the mass ratio of filtrate two to the mixture is 1:2.

[0085] The total phosphorus and soluble fluoride contents of phosphogypsum before and after the harmless treatment in the above embodiments were tested. The total phosphorus was tested by preparing a solution according to GB / T 23456-2009 phosphogypsum and then detecting it by ammonium molybdate spectrophotometry. The soluble fluoride was detected by ion-selective electrode method. After testing, the total phosphorus content decreased from 132.4 mg / L to 0.09 mg / L and the soluble fluoride content decreased from 67.17 mg / L to 0.13 mg / L after the harmless treatment.

[0086] In the above embodiments, the barium slag before and after harmless treatment was subjected to pH testing and toxicity leaching tests according to the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB5085.3-2007). The tests showed that after harmless treatment, the pH decreased from 12.34 to 6.84, and the barium ion concentration decreased from 1490 mg / L to 3.16 mg / L.

[0087] Example 4

[0088] This embodiment provides a method for the synergistic harmless treatment of phosphogypsum and barium slag. The difference between this method and Example 1 is that in step 3), glycidyl methacrylate is replaced with silane coupling agent KH560.

[0089] The total phosphorus and soluble fluoride contents of phosphogypsum before and after the harmless treatment in the above embodiments were tested. The total phosphorus was tested by preparing a solution according to GB / T 23456-2009 phosphogypsum and then detecting it by ammonium molybdate spectrophotometry. The soluble fluoride was detected by ion-selective electrode method. After testing, the total phosphorus content decreased from 130.5 mg / L to 32.26 mg / L and the soluble fluoride content decreased from 62.63 mg / L to 18.51 mg / L after the harmless treatment.

[0090] In the above embodiments, the barium slag before and after harmless treatment was subjected to pH testing and toxicity leaching tests according to the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB5085.3-2007). The tests showed that after harmless treatment, the pH decreased from 12.31 to 7.82, and the barium ion concentration decreased from 1532 mg / L to 13.52 mg / L.

[0091] Test Example 1

[0092] Solutions containing phosphate and fluoride ions (concentrations of 200 mg / L) were prepared using KH₂PO₄, NaF, and deionized water. The pH was adjusted using sodium hydroxide and hydrochloric acid. 25 mL of the solution and 0.05 g of the modified coal gangue composite material from Example 1 or Example 4 were added to a 50 mL centrifuge tube. The mixture was shaken at room temperature, and the effects of shaking time and pH on the adsorption of phosphate and fluoride ions by the modified coal gangue composite material from Example 1 or Example 4 were measured. Figure 1 and Figure 3 The graphs show the effect of oscillation time on the adsorption of phosphate and fluoride ions by the modified coal gangue composite materials in Examples 1 and 4 of this invention. Figure 2 and Figure 4 The graphs show the effect of pH on the adsorption of phosphate and fluoride ions by the modified coal gangue composite material in Examples 1 and 4 of this invention.

[0093] according to Figures 1-4 As shown in the test results of Examples 1-4, this method effectively fixes acid-soluble barium in barium slag and removes harmful pollutants such as soluble phosphorus, eutectic phosphorus, and fluorides from phosphogypsum, achieving synergistic harmless treatment of phosphogypsum and barium slag, and providing a greener and more environmentally friendly method for synergistic harmless treatment of phosphogypsum and barium slag. Furthermore, compared to the modified coal gangue composite material prepared in Example 4 of this invention, the modified coal gangue composite material prepared in Example 1 of this invention has a better effect on adsorbing and fixing phosphate and fluoride ions in the filtrate.

[0094] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for the synergistic harmless treatment of phosphogypsum and barium slag, characterized in that, include: The composite phosphogypsum raw material is obtained by co-grinding phosphogypsum, biomass, minerals and peroxides. Phosphate-solubilizing bacteria are added and the raw material is cured and washed with water to obtain filtrate one and filter residue one. An adsorbent was added to filtrate one for adsorption treatment, and solid-liquid separation was performed to obtain filtrate two and the adsorbent after adsorption treatment; The filter residue 1 and barium residue were mixed to obtain a mixture, and then filtrate 2 was added and allowed to stand for aging to obtain a phosphogypsum-barium residue composite.

2. The method according to claim 1, characterized in that, The adsorbent is a modified coal gangue composite material; the process of obtaining the modified coal gangue composite material is as follows: coal gangue, calcite and montmorillonite are ground and calcined to obtain the composite material, the composite material is soaked in chitosan solution and freeze-dried, the freeze-dried composite material is coupled in a mixture of solvent, cerium ammonium nitrate, nitric acid and glycidyl methacrylate under an inert atmosphere, and finally organic solvent and amino modifying agent are added for modification treatment.

3. The method according to claim 2, characterized in that, The mass ratio of the coal gangue, calcite, and montmorillonite is (5-10):1:1; And / or, the mass ratio of the composite material, solvent, cerium ammonium nitrate, nitric acid and glycidyl methacrylate is 5:(100-200):1:(0.1-0.5):(1-5); And / or, in the modification treatment, the mass ratio of the composite material, the organic solvent and the amino modifying agent is 1:(10-50):(1-5); And / or, the solvent is water; And / or, the organic solvent is N,N-dimethylformamide; And / or, the amino-modifying agent is aminoguanidine hydrochloride.

4. The method according to claim 2 or 3, characterized in that, The coal gangue, calcite, and montmorillonite are subjected to washing, drying, and crushing processes before grinding. And / or, the calcination temperature is 300-600℃, and the calcination time is 3-5h; And / or, the concentration of the chitosan solution is 1-3 wt%; And / or, the concentration of the nitric acid is 50-70 wt%; And / or, the soaking treatment lasts for 0.5-1 hour; And / or, the inert atmosphere is a nitrogen atmosphere; And / or, the duration of the coupling reaction is 2-5 hours; And / or, the temperature of the modification treatment is 100-120℃, and the duration of the modification treatment is 1-3h.

5. The method according to claim 1, characterized in that, The biomass is at least one of straw, sawdust, and peanut shells; And / or, the mineral is hydrotalcite and / or palygorskite; And / or, the peroxide is calcium peroxide and / or sodium peroxide; And / or, the phosphate-solubilizing bacteria are at least one of Penicillium, Aspergillus niger, lactic acid bacteria, and acetic acid bacteria; And / or, the mass ratio of the phosphogypsum, biomass, minerals and peroxide is (10-20):1:0.1:0.1; And / or, the mass ratio of the composite phosphogypsum raw material to phosphate-solubilizing bacteria is 100:(1-5).

6. The method according to claim 5, characterized in that, The phosphate-solubilizing bacteria are a mixture of Penicillium, Aspergillus niger, lactic acid bacteria, and acetic acid bacteria.

7. The method according to claim 6, characterized in that, The percentages of Penicillium, Aspergillus niger, Lactic acid bacteria, and Acetic acid bacteria are 1:1:1:

1.

8. The method according to claim 1, characterized in that, In the water washing process, the mass ratio of the cured composite phosphogypsum raw material to water is 1:(2-5); And / or, in the adsorption treatment, the mass ratio of filtrate to adsorbent is 100:(1-5); And / or, the mass ratio of the filter residue to the barium residue is (1-5):20; And / or, the mass ratio of the filtrate to the mixture is (1-5):

10.

9. The method according to claim 1, characterized in that, The duration of the maintenance treatment is 7-14 days; And / or, the duration of the static aging is 1-3 days; And / or, the duration of the adsorption treatment is 30 min; And / or, the phosphogypsum, biomass, minerals and peroxides are further subjected to sieving and drying treatment before co-grinding; And / or, the water washing process is as follows: first, the cured composite phosphogypsum raw material is mixed with water and allowed to stand for a period of time, and finally, solid-liquid separation is performed.

10. A phosphogypsum-barium slag composite, characterized in that, It is prepared by the method of synergistic harmless treatment of phosphogypsum and barium slag as described in any one of claims 1-9.

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