Multi-solid waste collaborative treatment method, solid waste mixture and application thereof

Abstract

The present application belongs to the technical field of solid waste resource utilization, and provides a multi-solid waste collaborative treatment method, a solid waste mixture and application thereof.The multi-solid waste collaborative treatment method of the present application performs water washing on phosphogypsum to obtain an acidic washing liquid and water-washed phosphogypsum; adjusts the pH value of the acidic washing liquid to 7.2-8.0 by using carbide slag to obtain a weak alkaline washing liquid; performs washing on electrolytic manganese residue by using the weak alkaline washing liquid to obtain water-washed electrolytic manganese residue; performs ball milling on lithium residue to obtain lithium residue powder; and the water-washed phosphogypsum, the water-washed electrolytic manganese residue, the lithium residue powder, slag powder and carbide slag are first stirred and mixed, and then water is added for second stirring and mixing to obtain a solid waste mixture.The method of the present application realizes complete solidification of residual trace impurities such as heavy metal ions and other substances in each solid waste; the obtained solid waste mixture is not prone to collapse and dam break when applied, and has low permeability of toxic elements.

Description

Technical Field

[0001] This invention relates to the field of solid waste resource utilization technology, and in particular to a method for the co-processing of multiple solid wastes, a solid waste mixture and its application. Background Technology

[0002] Industrial solid wastes that pose a significant impact on the environment and safety mainly include energy and coal chemical fly ash, slag, metallurgical waste, coal gangue, red mud, industrial by-product gypsum, calcium carbide slag, and mining tailings. Due to the limited technological level of industrial waste disposal in my country in the early days, many industrial solid wastes could only be treated through stockpiling, resulting in a massive stockpile. The stockpiling of industrial solid waste not only occupies a large amount of land resources and poses safety hazards such as dam failures and overflows, but also causes irreversible damage to the environment on which humanity depends for survival through the leaching of harmful substances.

[0003] Phosphogypsum is a solid waste generated in the wet-process phosphoric acid production process, and its main component is calcium sulfate dihydrate. The composition of phosphogypsum is relatively complex. In addition to calcium sulfate, it also contains incompletely decomposed phosphate rock, residual phosphoric acid, fluorides, acid-insoluble substances, organic matter, etc. Among these, the presence of fluorine and organic matter has the greatest impact on the resource utilization of phosphogypsum.

[0004] Due to processes such as acid leaching and sulfidation during production, electrolytic manganese slag, wastewater, and anode mud contain large amounts of harmful components such as soluble manganese, ammonia nitrogen, sulfides, and heavy metal ions. Traditional disposal methods have caused serious environmental damage and restricted the development of the electrolytic manganese industry.

[0005] Lithium slag is the residue discharged after spodumene is calcined at high temperatures, lithium carbonate is extracted using the sulfuric acid process, and the residue is filtered and washed. The comprehensive utilization of lithium slag faces several drawbacks, including small market demand and difficulty in disposal; low value and limited sales radius; the presence of harmful elements in some lithium smelting slag, making harmless treatment difficult; and high levels of elements such as iron, calcium, and sulfur, hindering high-value applications. Therefore, the stockpiling of lithium slag severely restricts the development of the new energy materials industry.

[0006] Calcium carbide slag is the waste residue mainly composed of calcium hydroxide after the hydrolysis of calcium carbide to produce acetylene gas. It is characterized by large production volume, strong alkalinity, difficulty in transportation, and soil erosion.

[0007] Currently, there are many ways to dispose of and utilize the above-mentioned solid wastes, but most of them suffer from problems such as low utilization rates, substandard environmental performance of solid waste products, and low market share. Among the most utilization methods for these solid wastes, high-temperature calcination is undoubtedly the simplest, most direct, and most effective. The physical properties and environmental indicators of the solid waste products can meet the corresponding standards, but the excessive energy consumption leads to poor economic viability and low market share. On the other hand, in non-calcination treatment, excessive solid waste content will affect the structural and environmental performance of the final solid waste products, while insufficient content means low comprehensive utilization rate of solid waste, insignificant social benefits, and the introduction of other high-priced raw materials will lead to excessively high production costs, resulting in weak motivation for solid waste utilization enterprises to dispose of the wastes. Summary of the Invention

[0008] In view of this, the purpose of this invention is to provide a method for the co-processing of multiple solid wastes, a solid waste mixture, and its application. The treatment method provided by this invention can achieve comprehensive utilization of phosphogypsum, carbide slag, electrolytic manganese slag, and lithium slag, and has low processing costs; in addition, the obtained solid waste mixture can be used for site preparation, roadbed, and mine backfilling, realizing the reuse of solid waste.

[0009] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0010] This invention provides a method for the co-processing of multiple solid wastes, comprising the following steps:

[0011] The phosphogypsum was washed with water to obtain an acidic washing solution and water-washed phosphogypsum.

[0012] The pH of the acidic washing solution was adjusted to 7.2-8.0 using carbide slag to obtain a weakly alkaline washing solution;

[0013] The electrolytic manganese slag is washed with the weakly alkaline washing solution to obtain water-washed electrolytic manganese slag.

[0014] The lithium slag was ball-milled to obtain lithium slag powder;

[0015] The water-washed phosphogypsum, the water-washed electrolytic manganese slag, the lithium slag powder, the slag powder, and the carbide slag are first stirred and mixed, and then water is added for a second stirring and mixing to obtain a solid waste mixture.

[0016] Preferably, during the water washing process, the mass ratio of phosphogypsum to water is 1:10~20, the water washing method is soaking and stirring, and the soaking and stirring time is 15~20 minutes.

[0017] Preferably, in the process of adjusting the pH of the acidic washing solution to 7.2-8.0 using carbide slag, the amount of carbide slag added is calculated according to Formula 1:

[0018] The amount of calcium carbide slag added = the volume of acidic washing solution × the weight conversion factor formula 1;

[0019] In Formula 1, the unit for the amount of carbide slag added is kg, and the unit for the volume of the acidic washing solution is m³. 3 The weight conversion factor is 0.04~0.05.

[0020] Preferably, during the washing process, the mass ratio of electrolytic manganese slag to weakly alkaline washing solution is 1:20~25, the washing method is soaking and stirring, and the soaking and stirring time is 5~10 minutes.

[0021] Preferably, the specific surface area of ​​the lithium slag powder is 450~600 m². 2 / kg.

[0022] Preferably, during the first stirring and mixing process, the mass ratio of water-washed phosphogypsum, water-washed electrolytic manganese slag, lithium slag powder, slag powder and carbide slag is 40~50:15~20:20~25:5~10:3~5.

[0023] Preferably, during the second stirring and mixing process, the mass of water is 15-20% of the total mass of water-washed phosphogypsum, water-washed electrolytic manganese slag, lithium slag powder, slag powder and carbide slag; the second stirring and mixing time is 5-10 minutes.

[0024] Preferably, after washing, a manganese slag washing solution is obtained; the manganese slag washing solution is used to absorb the gas generated during the first stirring and mixing process and the second stirring and mixing process.

[0025] The present invention also provides a solid waste mixture obtained by the method described in the above technical solution, wherein the pH value of the solid waste mixture is 11.5~12.5.

[0026] The present invention also provides the application of the solid waste mixture described in the above technical solution in site paving, roadbed and mine backfilling.

[0027] This invention provides a method for the co-processing of multiple solid wastes, comprising the following steps: washing phosphogypsum with water to obtain an acidic washing solution and washed phosphogypsum; adjusting the pH of the acidic washing solution to 7.2-8.0 using carbide slag to obtain a weakly alkaline washing solution; washing electrolytic manganese slag with the weakly alkaline washing solution to obtain washed electrolytic manganese slag; ball milling lithium slag to obtain lithium slag powder; first mixing the washed phosphogypsum, the washed electrolytic manganese slag, the lithium slag powder, slag powder, and carbide slag, and then adding water for a second mixing to obtain a solid waste mixture.

[0028] This invention involves washing phosphogypsum with water to remove residual impurities such as phosphoric acid, water-soluble fluoride ions, water-soluble magnesium oxide, and water-soluble sodium oxide. These impurities will then enter an acidic washing solution. The pH of this acidic washing solution is adjusted using carbide slag, making the solution alkaline. This ensures that the pH of the washing solution is approximately the same as that of the electrolytic manganese slag, thus preventing the release of NH4+ from the electrolytic manganese slag in subsequent operations. + When exposed to a strongly alkaline environment, it rapidly transforms into ammonia gas, which is released and pollutes the atmosphere. Simultaneously, calcium carbide slag can introduce calcium into the washing solution. 2+ With OH - The electrolytic manganese slag is washed with a weakly alkaline washing solution, causing the water-soluble ammonium salts and manganese ions in the slag to react chemically with the ions in the weakly alkaline washing solution to form precipitates or complex salt stabilizers, which then enter the water-washed electrolytic manganese slag. Ball milling activation of the lithium slag enables the transformation of some inert silica and inert alumina into active silica and active alumina, thereby accelerating their participation in the hydration reaction in the next step. The trace impurities remaining in the water-washed phosphogypsum, water-washed electrolytic manganese slag, and lithium slag powder will continue to form water-insoluble substances in the alkaline environment and be completely encapsulated in the mixture; under alkaline activation, the glassy structure surface of the slag powder is destroyed, and alkaline substances such as K2O and Na2O dissolved from the lithium slag powder react with OH... - Together, they act on the Si-O or Al-O bonds in the glass, leading to the destruction, decomposition, and dissolution of the glass network structure, accelerating the depolymerization of the glass. Calcium hydroxide in the carbide slag reacts with the active SiO2 dissolved in the system to form CSH gel. Simultaneously, due to the presence of sulfate ions dissolved from electrolytic manganese slag and phosphogypsum, the active calcium oxide and alumina in the slag powder and lithium slag powder combine with them to form ettringite. These hydration products are ultimately distributed in a network structure, thus giving the overall solid waste mixture coagulation and solidification characteristics. Furthermore, since lithium slag powder and water-washed electrolytic manganese slag already possess a certain mechanical strength, and the unreacted particles can fill the internal voids of the material, acting as fine aggregate, the resulting solid waste mixture possesses the mechanical strength appropriate for its age after the second mixing, thereby achieving complete solidification of residual trace impurities such as heavy metal ions in each solid waste. When the final solid waste mixture is used for site leveling, roadbed construction, and mine backfilling, it is not prone to collapse or dam failure, and has low permeability to toxic elements, preventing groundwater pollution. Meanwhile, the method of the present invention can treat a variety of solid wastes, and is simple to operate, requiring only water washing, rinsing and mixing, etc., making it simple to operate and low in cost. Detailed Implementation

[0029] This invention provides a method for the co-processing of multiple solid wastes, comprising the following steps:

[0030] The phosphogypsum was washed with water to obtain an acidic washing solution and water-washed phosphogypsum.

[0031] The pH of the acidic washing solution was adjusted to 7.2-8.0 using carbide slag to obtain a weakly alkaline washing solution;

[0032] The electrolytic manganese slag is washed with the weakly alkaline washing solution to obtain water-washed electrolytic manganese slag.

[0033] The lithium slag was ball-milled to obtain lithium slag powder;

[0034] The water-washed phosphogypsum, the water-washed electrolytic manganese slag, the lithium slag powder, the slag powder, and the carbide slag are first stirred and mixed, and then water is added for a second stirring and mixing to obtain a solid waste mixture.

[0035] Unless otherwise specified, all raw materials used in this invention are preferably commercially available products.

[0036] The present invention involves washing phosphogypsum with water to obtain an acidic washing solution and water-washed phosphogypsum.

[0037] In this invention, the mass ratio of phosphogypsum to water during the washing process is preferably 1:10-20. In this invention, the washing temperature is preferably room temperature, i.e., no additional heating or cooling is required. In this invention, the washing method is preferably immersion and stirring, and the immersion and stirring time is preferably 15-20 minutes. In this invention, the washing is preferably carried out in a stirring tank.

[0038] After the water washing, the present invention preferably also includes filtration, which is preferably carried out on a filter press. During the filtration process, the filter residue obtained by filtration is preferably rinsed, and the resulting rinsing liquid is combined with the acidic washing liquid.

[0039] In this invention, washing the phosphogypsum with water can remove residual impurities such as phosphoric acid, water-soluble fluoride ions, water-soluble magnesium oxide, and water-soluble sodium oxide. These impurities will then enter the acidic washing solution.

[0040] After obtaining the acidic washing solution, the present invention uses carbide slag to adjust the pH value of the acidic washing solution to 7.2~8.0 to obtain a weakly alkaline washing solution.

[0041] In this invention, during the process of adjusting the pH of the acidic washing solution to 7.2-8.0 using carbide slag, the amount of carbide slag added is preferably calculated according to Formula 1:

[0042] The amount of calcium carbide slag added = the volume of acidic washing solution × the weight conversion factor formula 1;

[0043] In Formula 1, the unit for the amount of carbide slag added is kg, and the unit for the volume of the acidic washing solution is m³. 3The weight conversion factor is 0.04~0.05. In a specific embodiment of the present invention, the weight conversion factor is preferably 0.042167.

[0044] In this invention, the pH of the acidic washing solution is adjusted to 7.2-8.0 using carbide slag, and then stirring is preferably performed for 5-10 minutes.

[0045] In this invention, the pH value of the acidic washing solution is adjusted using carbide slag, making the solution weakly alkaline. This ensures that the pH value of the washing solution is approximately the same as that of the electrolytic manganese slag, thereby preventing the NH4 in the electrolytic manganese slag from being released in the next step. + When exposed to a strongly alkaline environment, it rapidly transforms into ammonia gas, which is released and pollutes the atmosphere. Simultaneously, calcium carbide slag can introduce calcium into the washing solution. 2+ With OH - This provides assistance for the subsequent solidification of impurities and the generation of hydration products.

[0046] After obtaining the weakly alkaline washing solution, the present invention uses the weakly alkaline washing solution to wash the electrolytic manganese slag to obtain water-washed electrolytic manganese slag.

[0047] In this invention, the preferred mass ratio of electrolytic manganese slag to weakly alkaline washing solution during the washing process is 1:20-25. The preferred washing temperature is room temperature, i.e., no additional heating or cooling is required. The preferred washing method is soaking and stirring, with a preferred soaking and stirring time of 5-10 minutes. The washing is preferably carried out in a stirring tank.

[0048] In this invention, during the washing process, water-soluble ammonium salts and manganese ions in the electrolytic manganese slag react chemically with other impurity ions in the weakly alkaline washing solution to generate precipitates or double salt stabilizers. These precipitates or double salt stabilizers and the washed electrolytic manganese slag are combined after precipitation to form water-washed electrolytic manganese slag. The main chemical reactions occurring during the washing process are as follows:

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057] In this invention, during the washing process, as OH... - After washing, the pH value of the weakly alkaline washing solution decreases, changing from weakly alkaline to weakly acidic. The electrolytic manganese slag, in addition to the water-soluble ammonium salts (NH4+) that participate in the reaction... + Apart from manganese ions, the vast majority of excess water-soluble ammonium, potassium, and sodium salts will enter the manganese slag washing solution through washing.

[0058] Following the washing process, the present invention preferably also yields a manganese slag washing solution. In this invention, the manganese slag washing solution is preferably used to absorb the gas generated during the subsequent first and second stirring and mixing processes.

[0059] This invention involves ball milling lithium slag to obtain lithium slag powder.

[0060] In this invention, the ball milling is preferably carried out in a ball mill, and the ball milling temperature is preferably room temperature, i.e., neither additional heating nor additional cooling is required. In this invention, the specific surface area of ​​the lithium slag powder is preferably 450~600 m². 2 / kg.

[0061] In this invention, the lithium slag has a high silicon and aluminum content, and the specific surface area of ​​the lithium slag powder is reduced to 450-600 m² through ball milling. 2 / kg, which can realize the transformation of some inert silica and inert alumina in lithium slag into active silica and active alumina, thereby accelerating the process of participating in the hydration reaction in the next step.

[0062] After obtaining water-washed phosphogypsum, water-washed electrolytic manganese slag and lithium slag powder, the present invention first stirs and mixes the water-washed phosphogypsum, the water-washed electrolytic manganese slag, the lithium slag powder, slag powder and carbide slag, and then adds water for a second stirring and mixing to obtain solid waste mixture.

[0063] In this invention, the slag powder is a shorthand for granulated blast furnace slag powder, a high-quality concrete admixture. It is made from granulated blast furnace slag conforming to GB / T 203 standards, dried and ground to achieve a sufficiently fine particle size and a suitable activity index. Granulated blast furnace slag is an industrial solid waste residue obtained from the molten material, mainly composed of calcium aluminosilicate, obtained by smelting pig iron in a blast furnace in ironmaking plants. It is granulated after water quenching and is mostly glassy, ​​possessing potential hydraulic cementitious properties. Since slag powder has become a commercial building material, it does not require pretreatment before use; the slag powder manufacturer has already pretreated it and prepared it as a "slag powder" product.

[0064] In this invention, during the first stirring and mixing process, the preferred mass ratio of washed phosphogypsum, washed electrolytic manganese slag, lithium slag powder, slag powder, and carbide slag is 40~50:15~20:20~25:5~10:3~5. In this invention, the preferred temperature for the first stirring and mixing is room temperature, i.e., neither additional heating nor additional cooling is required. In this invention, the first stirring and mixing is preferably carried out in a forced mixer.

[0065] In this invention, during the second stirring and mixing process, the mass of water is preferably 15-20% of the total mass of the washed phosphogypsum, washed electrolytic manganese slag, lithium slag powder, slag powder, and calcium carbide slag. In this invention, the second stirring and mixing time is preferably 5-10 minutes. In this invention, the temperature of the second stirring and mixing is preferably room temperature, i.e., neither additional heating nor additional cooling is required. In this invention, the second stirring and mixing is preferably carried out in a forced mixer.

[0066] In this invention, when the washed phosphogypsum, washed electrolytic manganese slag, lithium slag powder, and added slag powder and carbide slag are first stirred and mixed, the entire system is alkaline. At this time, the trace impurities remaining in the washed phosphogypsum, washed electrolytic manganese slag, and lithium slag powder will continue to generate water-insoluble substances in the alkaline environment and be completely encapsulated in the mixture. Meanwhile, the residual NH4 in the washed electrolytic manganese slag... + Encountering high concentrations of OH - It will quickly convert into ammonia gas and escape, so the ammonia gas is collected and sent to the tail gas absorption tank.

[0067] Under alkaline activation, the glassy structure surface of the slag powder is destroyed, and the alkaline substances such as K2O and Na2O dissolved from the lithium slag powder react with OH-. - Together, they act on the Si-O or Al-O bonds in the glass, leading to the destruction, decomposition, and dissolution of the glass network structure, thus accelerating the depolymerization of the glass. Calcium hydroxide reacts with the dissolved active SiO2 in the system to form CSH gel. Simultaneously, due to the presence of sulfate ions dissolved from electrolytic manganese slag and phosphogypsum, the active calcium oxide and alumina in the slag powder and lithium slag powder combine with them to form ettringite. The main chemical reactions are as follows:

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074] For example, in the above reaction formula <cao>Represents active calcium oxide. <al2o3>This represents active aluminum oxide.

[0075] These hydration products eventually form a network structure, giving the overall material solidification properties. Since lithium slag powder and water-washed electrolytic manganese slag already possess a certain mechanical strength, and the unreacted particles can fill the internal voids of the material, acting as fine aggregates, the resulting solid waste mixture after the second mixing process possesses the mechanical strength appropriate for its age, thus achieving complete solidification of residual trace impurities such as heavy metal ions in each solid waste.

[0076] The present invention also provides a solid waste mixture obtained by the method described in the above technical solution. In the present invention, the pH value of the solid waste mixture is 11.5~12.5.

[0077] The present invention also provides the application of the solid waste mixture described in the above technical solution in site paving, roadbed and mine backfilling.

[0078] The present invention does not impose specific limitations on the application of the solid waste mixture; any method known to those skilled in the art can be used.

[0079] The following detailed description of the multi-solid waste co-treatment method, solid waste mixing material and its application provided by the present invention, with reference to the embodiments, should not be construed as limiting the scope of protection of the present invention.

[0080] Example 1

[0081] A method for co-processing multiple solid wastes includes the following steps:

[0082] S1: Fresh phosphogypsum is transported to mixing tank #1, water is added, the liquid-solid mass ratio is controlled at 10:1, and after stirring for 15 minutes, it is filtered and the filter residue is washed. The resulting filter residue is water-washed phosphogypsum, and the resulting filtrate is transported to mixing tank #2.

[0083] S2: Add an appropriate amount of carbide slag to the No. 2 mixing tank and stir for 5 minutes. At this time, the pH value of the solution in the No. 2 mixing tank is 7.8.

[0084] S3: Pretreatment of electrolytic manganese slag: The electrolytic manganese slag is transported to the No. 2 mixing tank, the liquid-solid mass ratio is controlled at 20:1, and then the mixture is stirred for 5 minutes. After stirring, the residue is filtered and washed. The resulting residue is the water-washed electrolytic manganese slag. The resulting filtrate manganese slag washing liquid is transported to the tail gas absorption tank.

[0085] S4: Pretreatment of lithium slag: The lithium slag is fed into a ball mill for ball milling. After ball milling, the specific surface area of ​​the lithium slag powder is measured to be 520 m². 2 / kg.

[0086] S5: Solid Waste Mixing: The washed phosphogypsum, washed electrolytic manganese slag, lithium slag powder, slag powder, and carbide slag obtained in the above steps are added to a forced mixer in a mass ratio of 42:20:25:8:5. Then, water equal to 15% of the total mass of the above materials is added. After mixing for 5 minutes, the mixture is removed to obtain a solid waste mixture. The pH value of the solid waste mixture is measured. The exhaust gas escaping from the mixer outlet is collected using a blower and transported to the tail gas absorption tank, where it is absorbed by the manganese slag washing liquid obtained in step S3.

[0087] Examples 2-6 follow the same process steps as Example 1, except for the process parameters and material ratios, as detailed in Table 1.

[0088] Table 1 Process parameters of the embodiment

[0089]

[0090] The solid waste mixture prepared in Examples 1-6 was placed in a mold and vibrated to compact it. Then, it was moved together with the mold into a standard curing room (temperature range 20℃±2℃, humidity above 95%RH) for curing. After 7 days, it was demolded to obtain solid waste specimens.

[0091] The compressive strength of the solid waste specimens was measured at 7 days and 28 days of curing. After measuring the compressive strength of the specimens at 28 days, the solid waste specimens were crushed and leachate was prepared according to the standard "Leaching Toxicity of Solid Waste - Horizontal Oscillation Method" (HJ557-2010). The total phosphorus, fluoride, ammonia nitrogen, manganese, and total water-soluble salts in the leachate were then measured. The results of the above indicators are shown in Table 2.

[0092] Comparative Example 1

[0093] Fresh phosphogypsum, electrolytic manganese slag, and lithium slag were added directly to a forced mixer along with slag powder and calcium carbide slag in a mass ratio of 40:20:25:10:5, without any pretreatment. Water, accounting for 20% of the total mass of the materials, was then added and mixed for 10 minutes to obtain a solid waste mixture with a pH of 9.8. Exhaust gas escaping from the mixer was collected using a blower and transported to a tail gas absorption tank. The mixture was then compacted in a mold and transferred to a standard curing room for curing. Demolding was not possible after 7 days, but was successful after 21 days, yielding solid waste specimens. The compressive strength of the specimen was measured to be 0.2 MPa at 28 days. The specimen was crushed and the leachate was prepared according to the standard "Leaching Toxicity of Solid Waste - Horizontal Oscillation Method" (HJ 557-2010). The total phosphorus, fluoride, ammonia nitrogen, manganese and total water-soluble salts of the leachate were then measured. The results are shown in Table 2.

[0094] Comparative Example 2

[0095] Before paving the cement-stabilized crushed stone layer for highways, multiple ring samples were taken from the compacted, leveled, and dried soil base course to test its compressive strength and pH value. The results showed that the compressive strength ranged from 0.3 to 1.1 MPa, and the pH value ranged from 7.1 to 7.5. All soil samples were crushed and mixed, and samples were prepared using the quartering method. Leachate was prepared according to the standard "Leaching Toxicity of Solid Waste - Horizontal Oscillation Method" (HJ 557). The total phosphorus, fluoride, ammonia nitrogen, manganese, and total water-soluble salts in the leachate were then measured. The results are shown in Table 2.

[0096] Table 2 Compressive strength and toxicity leaching data

[0097]

[0098] As shown in Table 2, the solid waste mixtures treated in Examples 1-6 exhibit significantly better compressive strength and leachate ecological indicators than Comparative Example 1 after compaction and curing. This fully demonstrates the necessity of pretreatment processes (washing, cleaning, and ball milling) for phosphogypsum, manganese slag, and lithium slag. Furthermore, all ecological indicators in Examples 1-6 meet the Class I requirements of the "Integrated Wastewater Discharge Standard" (GB8978-1996). Therefore, it can be concluded that a beneficial synergistic solidification reaction occurred between the various solid wastes, primarily phosphogypsum, in this invention. Additionally, the compressive strength of the solid waste mixtures treated in Examples 1-6 after compaction and curing is much higher than that in Comparative Example 2, indicating that the final solidified mixture can fully replace traditional soil-based materials for use in large-scale industrial site foundations, roadbed filling, mine backfilling, and other projects. This provides a large-scale solid waste utilization scenario for materials obtained through the synergistic treatment of multiple solid wastes based on phosphogypsum. The method of this invention avoids pollutants present when solid wastes are stored separately from seeping into water sources and affecting water quality; at the same time, after the substances in the solid wastes are solidified, they are not easily dissolved into water, thus avoiding secondary pollution and preventing the formation of a large number of voids when used as mine filler, thereby avoiding the risk of dam failure after filling.

[0099] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. < / cao>

Claims

1. A method for the co-processing of multiple solid wastes, characterized in that, Includes the following steps: The phosphogypsum was washed with water to obtain an acidic washing solution and water-washed phosphogypsum. The pH of the acidic washing solution was adjusted to 7.2-8.0 using carbide slag to obtain a weakly alkaline washing solution; The electrolytic manganese slag is washed with the weakly alkaline washing solution to obtain water-washed electrolytic manganese slag. The lithium slag was ball-milled to obtain lithium slag powder; The water-washed phosphogypsum, the water-washed electrolytic manganese slag, the lithium slag powder, the slag powder and the carbide slag are first stirred and mixed, and then water is added for a second stirring and mixing to obtain solid waste mixture. During the water washing process, the mass ratio of phosphogypsum to water is 1:10~20; In the process of adjusting the pH of the acidic washing solution to 7.2-8.0 using calcium carbide slag, the amount of calcium carbide slag added is calculated according to Formula 1, which is: The amount of calcium carbide slag added = the volume of acidic washing solution × the weight conversion factor; In Formula 1, the unit for the amount of carbide slag added is kg, and the unit for the volume of the acidic washing solution is m³. 3 The weight conversion factor is 0.04~0.05; During the washing process, the mass ratio of electrolytic manganese slag to weakly alkaline washing solution is 1:20~25; During the first mixing process, the mass ratio of water-washed phosphogypsum, water-washed electrolytic manganese slag, lithium slag powder, slag powder and carbide slag is 40~50:15~20:20~25:5~10:3~5; During the second mixing process, the mass of water is 15-20% of the total mass of water-washed phosphogypsum, water-washed electrolytic manganese slag, lithium slag powder, slag powder and carbide slag.

2. The method according to claim 1, characterized in that, The washing method is soaking and stirring, and the soaking and stirring time is 15-20 minutes.

3. The method according to claim 1, characterized in that, The washing method is soaking and stirring, and the soaking and stirring time is 5-10 minutes.

4. The method according to claim 1, characterized in that, The specific surface area of ​​the lithium slag powder is 450~600 m². 2 / kg.

5. The method according to claim 1, characterized in that, The second mixing time is 5-10 minutes.

6. The method according to claim 1, characterized in that, After washing, a manganese slag washing solution is obtained; the manganese slag washing solution is used to absorb the gas generated during the first stirring and mixing process and the second stirring and mixing process.

7. The solid waste mixture obtained by the method according to any one of claims 1 to 6, characterized in that, The pH value of the solid waste mixture is 11.5~12.

5.

8. The application of the solid waste mixture as described in claim 7 in site paving, roadbed and mine backfilling.

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