Calcium-based solid waste residue slurry desulfurizer, preparation method, desulfurization method, and soil remediation agent

Abstract

The application relates to a calcium-based solid waste residue slurry desulfurizer, a preparation method, a desulfurization method and a soil remediation agent, and belongs to the technical field of solid waste utilization. The calcium-based solid waste residue slurry is subjected to sedimentation treatment to obtain a calcium-based solid waste residue slurry reaction liquid; a phase change inhibitor is added into the calcium-based solid waste residue slurry reaction liquid to obtain a mixed slurry liquid; the mixed slurry liquid is subjected to solid-liquid separation to obtain a solid-phase material; the solid-phase material is mixed with water and a conditioning agent is added to obtain the calcium-based solid waste residue slurry desulfurizer. The desulfurizer can be used for a desulfurization reaction to obtain a desulfurization solution and a desulfurization solid residue; the desulfurization solution is subjected to neutralization reaction and then solid-liquid separation to obtain washing water filtrate and a by-product desulfurization solid residue; and the desulfurization solid residue and the by-product desulfurization solid residue are used for preparing a soil ecological remediation agent. The calcium-based solid waste residue slurry discharged from alumina is used for preparing the desulfurizer, which not only recycles alkali resources and reduces the loss of alumina, but also is used for flue gas desulfurization, realizes the purpose of resource utilization of solid waste, and has the values and significance of pollution reduction, carbon reduction and synergistic effect.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of solid waste utilization, and in particular to a calcium-based solid waste residue slurry desulfurizer, a preparation method, a desulfurization method and a soil remediation agent. BACKGROUND

[0002] In the process of producing alumina from bauxite ore, impurities in the ore need to be reacted with calcium-based materials to generate hydrocalumite, calcium carbonate, calcium aluminate and a mixture of hydrates thereof and alkali liquor, the alkali liquor is returned to the alumina system for continuous utilization, and the remaining mixture is calcium-based solid waste residue slurry which is sent to a red mud storage as general solid waste after solid-liquid separation. At present, there is no literature record on how to utilize the calcium-based solid waste residue slurry to realize waste utilization. SUMMARY

[0003] The application provides a calcium-based solid waste residue slurry desulfurizer, a preparation method, a desulfurization method and a soil remediation agent to solve the technical problem of how to utilize calcium-based solid waste residue slurry waste.

[0004] In a first aspect, the application provides a preparation method of a calcium-based solid waste residue slurry desulfurizer, including the following steps:

[0005] obtaining a calcium-based solid waste residue slurry reaction liquid;

[0006] adding a phase change inhibitor into the calcium-based solid waste residue slurry reaction liquid to obtain a mixed slurry;

[0007] performing solid-liquid separation on the mixed slurry to obtain a solid-phase material;

[0008] adding water to the solid-phase material and mixing the solid-phase material with a conditioning agent to obtain the calcium-based solid waste residue slurry desulfurizer;

[0009] The pH value of the calcium-based solid waste residue slurry desulfurizer is 7-10.

[0010] Optionally, the step of obtaining the calcium-based solid waste residue slurry reaction liquid specifically includes:

[0011] settling the calcium-based solid waste residue slurry to obtain a calcium-based solid waste residue slurry underflow;

[0012] diluting the calcium-based solid waste residue slurry underflow to obtain the calcium-based solid waste residue slurry reaction liquid;

[0013] The solid-liquid ratio of the calcium-based solid waste residue slurry reaction liquid is (0.1-1):1.

[0014] Optionally, the step of diluting the calcium-based solid waste residue slurry underflow specifically includes: stirring and mixing the calcium-based solid waste residue slurry underflow with hot water, the temperature is 72-98 DEG C, and the stirring time is 0.5-5 h.

[0015] Optionally, the phase transition inhibitor has a mass of 0.02% to 0.15% of the total mass of sodium and aluminum in the calcium-based solid waste residue slurry reaction solution; and / or,

[0016] The phase transition inhibitor at least includes one of the following: a sugar acid salt, cellulose, calcium wood, and sodium humate.

[0017] Optionally, the sugar acid salt is calcium gluconate and sodium gluconate.

[0018] Optionally, the mixed slurry is subjected to solid-liquid separation to obtain a solid phase material, specifically including:

[0019] The mixed slurry is subjected to a first pressure filtration, and then the solid is washed with hot water under pressure and subjected to a second pressure filtration to obtain a solid phase material and a first filtrate.

[0020] Optionally, the conditioning agent at least includes one of the following: citric acid, citrate, gluconate, tannic acid, and aminocarboxylate; and / or,

[0021] The mass of the conditioning agent is 0.005% to 0.5% of the total mass of the calcium-based solid waste residue slurry desulfurizer.

[0022] In a second aspect, the application provides a desulfurizer prepared by the preparation method of the calcium-based solid waste residue slurry desulfurizer of the first aspect.

[0023] In a third aspect, the application provides a desulfurization method, including the following steps:

[0024] obtaining the calcium-based solid waste residue slurry desulfurizer of the second aspect;

[0025] subjecting the calcium-based solid waste residue slurry desulfurizer to a desulfurization reaction with flue gas to be desulfurized to obtain a desulfurized slurry;

[0026] The pH of the desulfurization reaction is 4.8 to 6.2.

[0027] Optionally, the calcium-based solid waste residue slurry desulfurizer is subjected to a desulfurization reaction with flue gas to be desulfurized to obtain a desulfurized slurry, specifically including:

[0028] The calcium-based solid waste residue slurry desulfurizer is fed into a desulfurization reactor and subjected to a reverse desulfurization reaction with flue gas to be desulfurized to obtain a desulfurized slurry.

[0029] Optionally, the temperature of the flue gas to be desulfurized in the desulfurization reaction is 50°C to 150°C.

[0030] Optionally, after the calcium-based solid waste residue slurry desulfurizer is subjected to a desulfurization reaction with flue gas to be desulfurized to obtain a desulfurized slurry, the method further includes:

[0031] The desulfurization slurry is subjected to solid-liquid separation to obtain a desulfurization solution and a desulfurization solid residue.

[0032] Optionally, when the desulfurization solution meets a set condition, the desulfurization solution is subjected to a neutralization reaction to obtain a by-product desulfurization solid residue.

[0033] The set condition includes that the total mass concentration of sodium and aluminum in the desulfurization solution is greater than 25 g / L.

[0034] Optionally, the neutralization reaction of the desulfurization solution specifically includes: adding a neutralization reagent into the desulfurization solution for reaction; and subjecting the reacted desulfurization solution to solid-liquid separation to obtain a by-product desulfurization solid residue and a washing water filtrate.

[0035] The neutralization reagent includes at least one of lime, calcium-silicon slag and calcium silicate.

[0036] Optionally, the washing water filtrate can be recycled into a desulfurization agent preparation process and mixed with a calcium-based solid waste residue slurry.

[0037] Optionally, in the neutralization reaction, the reaction temperature is 40-100 DEG C, the mass ratio of the desulfurization solution to the neutralization reagent is 10: (0.1-1.5), and the pH value is 7.2-10.5.

[0038] In a fourth aspect, the present application provides a soil remediation agent, which includes the desulfurization solid residue and / or the by-product desulfurization solid residue in the third aspect.

[0039] Optionally, the soil remediation agent includes, in terms of mass fraction, 1-7 parts of the desulfurization solid residue and / or the by-product desulfurization solid residue, 10-25 parts of red mud, 1-3 parts of wood ash and 2-6 parts of soil.

[0040] Compared with the prior art, the above technical solution provided in the embodiments of the present application has the following advantages:

[0041] The application discloses a calcium-based solid waste residue slurry desulfurizer, a preparation method, a desulfurization method and a soil remediation agent.

[0042] The method uses solid waste calcium-based solid waste residue slurry as raw material to prepare the desulfurizer, realizes resource utilization of the solid waste, achieves zero emission of the solid waste, and reduces the operation cost of flue gas desulfurization and the production cost of aluminum oxide. BRIEF DESCRIPTION OF DRAWINGS

[0043] The drawings incorporated into the specification and forming a part thereof, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, those skilled in the art can obtain other drawings according to these drawings without any creative effort.

[0045] Figure 1 A preparation method flowchart of a calcium-based solid waste residue slurry desulfurizer according to some embodiments of the present application;

[0046] Figure 2 A desulfurization method schematic diagram of a calcium-based solid waste residue slurry according to some embodiments of the present application. DETAILED DESCRIPTION

[0047] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of the present application.

[0048] Various embodiments of the present application can exist in the form of a range; it should be understood that the description in the form of a range is merely for the convenience and brevity, and should not be understood as a hard limitation on the scope of the present application; therefore, it should be considered that the described range has been specifically disclosed all possible sub-ranges and single values within the range; for example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, regardless of the range; in addition, whenever a numerical range is indicated in this document, it refers to any cited number (fraction or integer) within the indicated range.

[0049] In this document, the term includes "includes" and the like means "including but not limited to". The relationship terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. "And / or" describes the relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which means that A exists alone, A and B exist together, and B exists alone; where A and B can be singular or plural. "At least one" means one or more, "multiple" means two or more; "at least one", "at least one of the following" or the like means any combination of the items, including single item or combination of multiple items; for example, "at least one of a, b or c", or "at least one of a, b and c", can mean a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, where a, b and c can be single or multiple. "Fractional representation" such as weight parts, mass parts, etc. represents the proportional relationship between components. In the proportional relationship described in this document, the parameters that need to be described in order should be understood as the front item of the proportional form, and the proportional number should be understood as the latter item of the proportional form, for example, the mass ratio of substance A, substance B and substance C is 1:2:3, then substance A, substance B and substance C should be in the proportional form according to the description order and the proportional number one by one, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0050] Unless otherwise specifically indicated, all raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or prepared by existing methods.

[0051] Figure 1 A flowchart of a preparation method of a calcium-based solid waste residue slurry desulfurizer according to some embodiments of the present application is shown in the figure.

[0052] As shown in the figure, the present application provides a preparation method of a calcium-based solid waste residue slurry desulfurizer, which comprises: Figure 1

[0053] S1, obtaining a calcium-based solid waste residue slurry reaction solution;

[0054] S2, adding a phase change inhibitor to the calcium-based solid waste residue slurry reaction solution to obtain a mixed slurry solution;

[0055] S3, performing solid-liquid separation on the mixed slurry solution to obtain a solid phase material;

[0056] S4, adding water to the solid phase material and mixing with a conditioning agent to obtain a calcium-based solid waste residue slurry desulfurizer;

[0057] The pH value of the calcium-based solid waste residue slurry desulfurizer is 7-10.

[0058] In the above embodiments, a calcium-based solid waste residue slurry reaction solution is obtained, which mainly contains unstable hydrocalumite, calcium carbonate, calcium aluminate and its hydrates; a phase change inhibitor is added to the calcium-based solid waste residue slurry reaction solution to inhibit the reaction between calcium hydroxide and aluminum oxide in the reaction solution, reduce the generation of hydrocalumite, further reduce the generation of stable calcium aluminate and its hydrates, and at the same time generate more calcium carbonate material, thereby reducing the loss of aluminum oxide, to obtain a mixed slurry solution; the mixed slurry solution is subjected to solid-liquid separation, most of the sodium oxide and aluminum oxide are discharged through the filtrate, and the solid phase material such as calcium carbonate, calcium aluminate and its hydrates, and hydrocalumite is left; the solid phase material is mixed with a conditioning agent to obtain a calcium-based solid waste residue slurry desulfurizer; the pH value of the calcium-based solid waste residue slurry desulfurizer after conditioning is 7-10, which can improve the desulfurization performance of calcium aluminate and its hydrates, break the gelation of active silicon, aluminum and magnesium, reduce the agglomeration of active silicon and aluminum oxide, and at the same time enhance the oxidation and filtration performance of the desulfurization byproduct.

[0059] The present method uses solid waste calcium-based solid waste residue slurry as raw material to prepare a desulfurizer, realizes the resource utilization of solid waste, achieves zero emission of solid waste, and reduces the operation cost of flue gas desulfurization and the production cost of aluminum oxide.

[0060] As an optional embodiment, the obtaining of the calcium-based solid waste residue slurry reaction solution specifically comprises:

[0061] ​S11, the calcium-based solid waste residue slurry is settled to obtain a calcium-based solid waste residue slurry underflow;

[0062] S12, the calcium-based solid waste residue slurry underflow is diluted to obtain a calcium-based solid waste residue slurry reaction liquid;

[0063] The solid-liquid ratio in the calcium-based solid waste residue slurry reaction liquid is (0.1-1):1.

[0064] In the above embodiment, the calcium-based solid waste residue slurry is settled in a settling tank to obtain a calcium-based solid waste residue slurry underflow with higher solid content and a settling tank overflow, the settling tank overflow is sent to an alumina slurry dilution tank to recover part of the sodium hydroxide, and the calcium-based solid waste residue slurry underflow is sent to an alkali recovery reaction tank for dilution to prepare a calcium-based solid waste residue slurry reaction liquid. The settling process not only increases the solid content of the prepared calcium-based solid waste residue slurry reaction liquid, but also reduces the alkali concentration in the prepared calcium-based solid waste residue slurry reaction liquid.

[0065] The reason for controlling the solid-liquid ratio in the calcium-based solid waste residue slurry reaction liquid to be (0.1-1):1 is that a suitable solid-liquid ratio helps to improve the sodium oxide removal effect and reduce the water content of the solid phase material obtained after the later solid-liquid separation. When the solid-liquid ratio is greater than 1:1, the solid-liquid separation effect will be affected, and the sodium oxide content of the solid phase material after solid-liquid separation is higher. When the solid-liquid ratio is less than 0.1:1, the solid-liquid separation time will be increased, and the water content of the solid phase material after solid-liquid separation is higher. Illustratively, the solid-liquid ratio can be 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1 or 1:1.

[0066] As an optional embodiment, the dilution of the calcium-based solid waste residue slurry underflow specifically includes: stirring and mixing the calcium-based solid waste residue slurry underflow with hot water, the temperature is 72-98℃, and the stirring time is 0.5-5h, so that the reaction liquid is fully mixed and uniform.

[0067] In the above embodiment, the reason for using hot water for dilution and controlling the temperature of the phase change inhibitor to be 72-98℃ is that both the temperature and the stirring conditions will directly affect the reaction of calcium oxide and alumina. When the temperature is higher than 98℃, the loss of alumina will be increased, and more hydrocalumite will be generated. When the temperature is lower than 72℃, the reaction of calcium oxide and alumina in the reaction liquid is almost impossible to proceed, and the effect is poor. Illustratively, the temperature of the calcium-based solid waste residue slurry reaction liquid when the phase change inhibitor is added can be 72, 75, 78, 80, 82, 85, 88, 90, 92, 95 or 98℃.

[0068] As an optional embodiment, the mass of the phase change inhibitor is 0.02%-0.15% of the total mass of sodium and aluminum in the calcium-based solid waste residue slurry reaction liquid.

[0069] In the above embodiment, the reason for controlling the mass fraction of the phase change inhibitor to be 0.02% to 0.15% of the total mass of sodium and aluminum in the calcium-based solid waste residue slurry reaction liquid is to ensure that all calcium hydroxide in the calcium-based solid waste residue slurry reaction liquid is converted into calcium carbonate, and to avoid the participation of aluminum oxide in the reaction and reduce the loss of aluminum oxide. If the mass fraction is less than 0.02%, the phase transition of calcium hydroxide cannot be promoted; if the mass fraction is greater than 0.15%, the reaction effect of the phase change inhibitor is almost not increased, calcium hydroxide has been completely converted into calcium carbonate, and instead, the phase change inhibitor is wasted, increasing the cost. For example, the added mass of the phase change inhibitor accounts for 0.02%, 0.04%, 0.05%, 0.06%, 0.08%, 0.1%, 0.12%, 0.14%, and 0.15% of the total mass of sodium and aluminum in the calcium-based solid waste residue slurry reaction liquid.

[0070] The principle of the phase change inhibitor is to adsorb on the unstable intermediate phase surface active sites of calcium aluminate, inhibit the diffusion reaction of active substances on these surface active sites, and accelerate the conversion of the unstable intermediate phase of calcium aluminate into calcium carbonate and aluminum oxide. As an optional embodiment, the phase change inhibitor at least includes one of the following: calcium gluconate, potassium gluconate, cellulose, wood calcium, and sodium humate.

[0071] In the above embodiment, the phase change inhibitor can be any one of calcium gluconate, potassium gluconate, cellulose, wood calcium, and sodium humate, or a mixture of any two of them, or a mixture of any three or four of them, or a mixture of all five of them.

[0072] As an optional embodiment, the solid-liquid separation of the mixed slurry to obtain a solid phase material specifically includes:

[0073] The mixed slurry is subjected to primary pressure filtration, and then the solid is washed with hot water under pressure and subjected to secondary pressure filtration to obtain a solid phase material and a primary filtrate.

[0074] In the above-mentioned embodiments, the reaction solution to which the phase change inhibitor is added is obtained after reaction; the mixed slurry is obtained by the procedure of twice pressure filtration and once washing; first, the mixed slurry is subjected to once pressure filtration to realize the separation of solid and liquid in the mixed slurry, and most of the solution containing sodium oxide and aluminum oxide is discharged; fresh hot water is added under the pressure filtration state, and the remaining solid is soaked again, and then the remaining solid is subjected to twice pressure filtration to remove the residual alkali and aluminum in the remaining solid, thereby realizing the recovery of alkali and aluminum oxide in the mixed slurry, and the solution containing alkali and aluminum can be directly sent to the aluminum oxide red mud settling system to realize the recovery.

[0075] As an optional embodiment, the conditioning agent at least includes one of the following: citric acid, citrate, gluconate, tannic acid, aminocarboxylate;

[0076] In the above-mentioned embodiments, the citrate is one or more of a mixture of calcium citrate, iron citrate, magnesium citrate, and ammonium citrate; the gluconate is a mixture of calcium gluconate and sodium gluconate; and the aminocarboxylate is one or more of a mixture of trisodium nitrilotriacetate, tetrasodium ethylenediaminetetraacetate, and disodium magnesium ethylenediaminetetraacetate.

[0077] As an optional embodiment, the mass of the conditioning agent is 0.005% to 0.5% of the mass of the calcium-based solid waste residue slurry desulfurizer.

[0078] In the above-mentioned embodiments, the reason for controlling the mass of the conditioning agent to be 0.005% to 0.5% of the mass of the calcium-based solid waste residue slurry desulfurizer is that the conditioning agent can change the desulfurization efficiency of the slurry, enhance the agglomeration and precipitation performance of impurities, improve the desulfurization performance of calcium aluminate, and at the same time, break the aggregation of carbon and active silicon in the slurry, reduce the foaming of the slurry, and promote the discharge of aluminum ions. When the addition amount is greater than 0.5%, not only is the conditioning agent wasted, but also more substances enter the desulfurization slurry, which in turn causes the desulfurization efficiency to decrease; when the addition amount is less than 0.005%, the conditioning effect of the slurry changes little, and the desulfurization efficiency and the desulfurization performance of the slurry are not changed.

[0079] In a second aspect, based on the overall inventive concept, the present application provides a desulfurizer prepared by the preparation method of the calcium-based solid waste residue slurry desulfurizer according to the first aspect.

[0080] The desulfurizer is prepared based on the preparation method of the calcium-based solid waste residue slurry desulfurizer, and the specific steps of the preparation method can refer to the above-mentioned embodiments. Since the desulfurizer adopts part or all of the technical solutions of the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here.

[0081] In a third aspect, the present application provides a desulfurization method, which comprises the following steps:

[0082] obtaining the calcium-based solid waste residue slurry desulfurizer of the second aspect;

[0083] carrying out a desulfurization reaction on the calcium-based solid waste residue slurry desulfurizer and flue gas to be desulfurized to obtain desulfurized slurry;

[0084] The pH of the desulfurization reaction is 4.8-6.2.

[0085] In the above embodiments, the calcium-based solid waste residue slurry desulfurizer is used to carry out a desulfurization reaction with flue gas, which can realize the recycling of the calcium-based solid waste residue slurry. In addition, since the conditioning agent is added to the desulfurizer, the enrichment of aluminum ions in the solution in the calcium aluminate and its hydrates is reduced, the aluminum ions are discharged together with the desulfurization by-products, the influence of sodium on the desulfurization efficiency is further reduced, the enrichment reaction of sodium-calcium in the desulfurization system is reduced, and the plugging and scaling of the desulfurization system is reduced. Finally, the filtration performance of the desulfurized slurry is improved, the silicon-aluminum agglomeration performance of the desulfurized slurry is reduced, the gelation of active silicon, aluminum and magnesium is broken, and the water content of the desulfurization by-products is reduced. For example, the pH of the desulfurization reaction can be 4.8, 4.9, 5.0, 5.1, 5.2, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1 or 6.2.

[0086] As an optional embodiment, the desulfurization reaction of the calcium-based solid waste residue slurry desulfurizer and flue gas to be desulfurized to obtain desulfurized slurry specifically includes:

[0087] The calcium-based solid waste residue slurry desulfurizer is fed into a desulfurization reactor to carry out a reverse desulfurization reaction with flue gas to be desulfurized to obtain desulfurized slurry.

[0088] In the above embodiments, the reverse desulfurization reaction can make the flue gas to be desulfurized and the desulfurizer fully contact, and maximize the desulfurization reaction.

[0089] As an optional embodiment, the temperature of the flue gas to be desulfurized in the desulfurization reaction is 50-150°C.

[0090] In the above embodiments, the temperature of the flue gas to be desulfurized is controlled to be 50-150°C because the temperature affects the desulfurization efficiency and the amount of sulfur fixation. When the flue gas temperature exceeds 150°C, the reaction temperature is too high, the desulfurizer slurry evaporates a large amount, the solid-liquid ratio is difficult to control, and the desulfurization efficiency decreases. When the flue gas temperature is lower than 50°C, the flue gas desulfurization efficiency is slow, and the amount of desulfurizer slurry used is large. For example, the temperature of the flue gas to be desulfurized in the desulfurization reaction is 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C or 150°C.

[0091] As an optional implementation, the calcium-based solid waste residue slurry desulfurization agent is subjected to a desulfurization reaction with flue gas to be desulfurized, and desulfurized slurry is obtained.

[0092] The desulfurized slurry is subjected to solid-liquid separation to obtain desulfurized solution and desulfurized solid residue.

[0093] In the above implementation, the desulfurized solution contains excess alkali, aluminum, silicon and other substances, which can participate in the preparation process of the calcium-based solid waste residue slurry desulfurization agent, or can be used after neutralization treatment; the main components of the desulfurized solid residue are calcium sulfate, calcium oxide, silicon oxide, aluminum oxide and the like, and the pH value is 6-9, which can be used as a soil modifier.

[0094] As an optional implementation, when the desulfurized solution meets a set condition, the desulfurized solution is subjected to a neutralization reaction to obtain a by-product desulfurized solid residue.

[0095] The set condition includes that the total mass concentration of sodium and aluminum in the desulfurized solution is >25g / L.

[0096] In the above implementation, when the total mass concentration of sodium and aluminum in the desulfurized solution is less than 25g / L, the desulfurized solution can be used to prepare a calcium-based solid waste residue slurry desulfurization agent, such as being used in combination with a conditioning agent; and when the total mass concentration of sodium and aluminum in the desulfurized solution is >25g / L, the desulfurized solution needs to be subjected to a neutralization reaction first to remove sodium and aluminum in the filtrate and reduce the content of sodium and aluminum in the filtrate.

[0097] As an optional implementation, the neutralization reaction of the desulfurized solution specifically includes: adding a neutralization reagent to the desulfurized solution for reaction; and the reacted desulfurized solution is subjected to solid-liquid separation to obtain a by-product desulfurized solid residue and a washing water filtrate.

[0098] The neutralization reagent includes at least one of lime, calcium-silicon slag and calcium silicate.

[0099] In the above implementation, one or more of lime, calcium-silicon slag and calcium silicate are used for reaction, which can react with sodium ions and aluminum ions in the desulfurized solution to generate calcium sulfate and aluminum hydroxide precipitates, thereby realizing the discharge of impurities.

[0100] As an optional implementation, the washing water filtrate can be recycled into the desulfurization agent preparation process and mixed with the calcium-based solid waste residue slurry.

[0101] As an optional implementation, in the neutralization reaction, the reaction temperature is 40-100℃, the mass ratio of the desulfurized solution to the neutralization reagent is 10:(0.1-1.5), and the pH value is controlled at 7.2-10.5.

[0102] In the above embodiments, the reason for controlling the reaction temperature to be 40-100°C is that the temperature affects the efficiency of the neutralization reaction. When the reaction temperature is lower than 40°C, the reaction speed is too slow, the reaction is insufficient, more neutralizing agent needs to be added, and the cost is higher. For example, the reaction temperature can be 40°C, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C.

[0103] In a fourth aspect, the application provides a soil remediation agent comprising the desulfurization solid residue and / or the by-product desulfurization solid residue of the third aspect.

[0104] In the above embodiments, the desulfurization solid residue mainly contains calcium sulfate, calcium oxide, silicon oxide, aluminum oxide and the like, and has a pH value of 6-9. The by-product desulfurization solid residue mainly contains calcium sulfate, calcium sulfite, aluminum sulfate, silicon oxide, and has a pH value of 7.5-10, and can be used as a soil remediation agent.

[0105] As an optional embodiment, the soil remediation agent comprises 1-7 parts by mass of the desulfurization solid residue and / or the by-product desulfurization solid residue, 10-25 parts by mass of red mud, 1-3 parts by mass of wood ash, and 2-6 parts by mass of soil.

[0106] In the above embodiments, the reason for controlling the mass fraction of the soil remediation agent is that the red mud is a clay mineral mainly composed of silicates, iron oxides, aluminum hydroxides and the like. The wood ash can adjust the pH value of the soil, mainly contains carbonates and trace elements, and improves the soil structure. When used together with the desulfurization solid residue and / or the by-product desulfurization solid residue, the soil remediation agent can be used as a remediation agent for alkaline contaminated land.

[0107] The application will be further described below with reference to specific examples. In the following examples, the experimental methods not specified in the specific conditions are generally determined according to the national standards / industry standards. If there is no corresponding national standard / industry standard, the general international standard, the conventional condition or the condition suggested by the manufacturer is used.

[0108] In the following examples and comparative examples, the experimental conditions of the desulfurization reaction are as follows: the SO2 concentration is 1000 mg / m 3 10000 mg / m 3 The pH value of the desulfurization slurry below 4.8 is used as the control index of the desulfurization reaction time.

[0109] Example 1

[0110] The present embodiment provides a desulfurization agent, and the preparation method comprises the following steps:

[0111] S1, the calcium-based solid waste residue slurry is sent into a pre-settling tank, the underflow of the settling tank is sent to an alkali recovery reaction tank and diluted with hot water, and after stirring for 0.5 h, a calcium-based solid waste residue slurry reaction liquid is obtained; wherein the temperature of the calcium-based solid waste residue slurry reaction liquid is 70°C, and the solid-liquid ratio is 0.4;

[0112] S2, the calcium-based solid waste residue slurry reaction liquid is added into a phase change inhibitor to obtain a mixed slurry; wherein the amount of the phase change inhibitor is 0.05% of the total mass of sodium and aluminum in the reaction liquid, and the phase change inhibitor includes calcium gluconate 3 parts, potassium gluconate 5 parts, and cellulose 2 parts;

[0113] S3, the mixed slurry is subjected to pressure filtration, washing, and re-pressure filtration in a first liquid-solid separation device to obtain a first filtrate and a solid phase material;

[0114] S4, the solid phase material is mixed with water, the temperature is adjusted to 65℃, and a conditioning agent is added to obtain a calcium-based solid waste residue slurry desulfurizer with a pH value of 8.2; wherein the mass of the conditioning agent is 0.01% of the total mass of the calcium-based solid waste residue slurry desulfurizer; and the conditioning agent includes calcium citrate 1 part, sodium citrate 1 part, ethylenediaminetetraacetic acid disodium magnesium salt 3 parts, calcium gluconate and sodium gluconate each 0.5 part.

[0115] It is used for desulfurization reaction, which includes the following steps:

[0116] The prepared calcium-based solid waste residue slurry desulfurizer is sent to a desulfurization reactor to perform a reverse desulfurization reaction with 50℃ flue gas to be desulfurized to obtain a desulfurization slurry;

[0117] When the pH value of the desulfurization circulating slurry is lower than 4.8, the desulfurization slurry is sent to a secondary solid-liquid separation device for solid-liquid separation to obtain a desulfurization solution and a desulfurization solid residue.

[0118] The content of sodium and aluminum in the desulfurization solution is not more than 25g / L, so the desulfurization solution is directly used as the batching water of the solid phase material;

[0119] The desulfurization solid residue is used to prepare a soil remediation agent as an alkaline contaminated soil ecological remediation agent, and the specific components include: desulfurization solid residue 2 parts, red mud 12 parts, wood ash 1.3 parts, and soil 2.6 parts.

[0120] Through chemical analysis of the desulfurization solid residue, the sulfur retention amount of the desulfurization solid residue is 35.1%, the sodium oxide content is 0.02%, the aluminum oxide content is 0.49%, and the water content is 7.8%.

[0121] Example 2

[0122] The embodiment provides a desulfurizer, and the preparation method includes the following steps:

[0123] S1, the calcium-based solid waste residue slurry is sent into a pre-settling tank, the underflow of the settling tank is sent to an alkali recovery reaction tank and diluted with hot water, and after stirring for 3h, a calcium-based solid waste residue slurry reaction liquid is obtained; wherein the temperature of the calcium-based solid waste residue slurry reaction liquid is 90℃, and the solid-liquid ratio is 0.3;

[0124] S2, the calcium-based solid waste residue slurry reaction liquid is added into a phase change inhibitor to obtain a mixed slurry; wherein, the amount of the phase change inhibitor is 0.11% of the total mass of sodium and aluminum in the reaction liquid, and the phase change inhibitor includes calcium gluconate 1 part, potassium gluconate 5 parts, cellulose 3 parts, calcium carbonate 0.5 parts, and sodium humate 0.1 parts;

[0125] S3, the mixed slurry is subjected to pressure filtration, washing, and re-pressure filtration in a first liquid-solid separation device to obtain a first filtrate and a solid phase material;

[0126] S4, the solid phase material is mixed with water, and a conditioning agent is added at a temperature of 80℃ to obtain a calcium-based solid waste residue slurry desulfurizer with a pH value of 7; wherein, the mass of the conditioning agent is 0.5% of the total mass of the calcium-based solid waste residue slurry desulfurizer; and the conditioning agent includes ammonium citrate 3 parts, trisodium nitrilotriacetate 0.8 parts, ethylenediaminetetraacetic acid disodium magnesium salt 3 parts, calcium gluconate and sodium gluconate each 0.5 parts.

[0127] The calcium-based solid waste residue slurry desulfurizer is used for a desulfurization reaction, which includes the following steps:

[0128] The prepared calcium-based solid waste residue slurry desulfurizer is sent to a desulfurization reactor to perform a reverse desulfurization reaction with 60℃ flue gas to be desulfurized to obtain a desulfurization slurry;

[0129] When the pH value of the desulfurization circulating slurry is lower than 4.8, the desulfurization slurry is sent to a secondary solid-liquid separation device for solid-liquid separation to obtain a desulfurization solution and a desulfurization solid residue.

[0130] The content of sodium and aluminum in the desulfurization solution is not more than 25g / L, so the desulfurization solution is directly used as the batching water of the solid phase material;

[0131] The desulfurization solid residue is used for preparing a soil remediation agent as an alkaline contaminated soil ecological remediation agent, and the specific components include: desulfurization solid residue 1 part, red mud 25 parts, wood ash 3 parts, and soil 4 parts.

[0132] Through chemical analysis of the desulfurization solid residue, the sulfur retention amount of the desulfurization solid residue is 36.2%, the content of sodium oxide is 0.015%, the content of aluminum oxide is 0.4%, and the water content is 7.0%.

[0133] Example 3

[0134] The embodiment provides a desulfurizer, and a preparation method thereof includes the following steps:

[0135] S1, the calcium-based solid waste residue slurry is sent into a pre-settling tank, the underflow of the settling tank is sent to an alkali recovery reaction tank and diluted with hot water, and after stirring for 5h, a calcium-based solid waste residue slurry reaction liquid is obtained; wherein, the temperature of the calcium-based solid waste residue slurry reaction liquid is 95℃, and the solid-liquid ratio is 1;

[0136] S2, the calcium-based solid waste residue slurry reaction liquid is added into a phase change inhibitor to obtain a mixed slurry; wherein, the amount of the phase change inhibitor is 0.15% of the total mass of sodium and aluminum in the reaction liquid, and the phase change inhibitor includes calcium gluconate 0.1 part, potassium gluconate 0.5 part, cellulose 2 parts, wood calcium 1 part, and sodium humate 0.5 part;

[0137] S3, the mixed slurry is subjected to pressure filtration, washing, and re-pressure filtration in a first liquid-solid separation device to obtain a first filtrate and a solid phase material;

[0138] S4, the solid phase material is mixed with water, and a conditioning agent is added at a temperature of 90℃ to obtain a calcium-based solid waste residue slurry desulfurizer with a pH value of 10; wherein, the mass of the conditioning agent is 0.005% of the total mass of the calcium-based solid waste residue slurry desulfurizer; and the conditioning agent includes sodium citrate 2 parts, ferric citrate 1 part, ethylenediaminetetraacetic acid tetrasodium salt 1 part, calcium gluconate and sodium gluconate each 0.5 part.

[0139] The calcium-based solid waste residue slurry desulfurizer is used for a desulfurization reaction, which includes the following steps:

[0140] The prepared calcium-based solid waste residue slurry desulfurizer is sent to a desulfurization reactor to perform a reverse desulfurization reaction with 150℃ flue gas to be desulfurized to obtain a desulfurization slurry;

[0141] When the pH value of the desulfurization circulating slurry is lower than 4.8, the desulfurization slurry is sent to a secondary solid-liquid separation device for solid-liquid separation to obtain a desulfurization solution and a desulfurization solid residue.

[0142] The content of sodium and aluminum in the desulfurization solution is not more than 25g / L, so the desulfurization solution is directly used as the batching water of the solid phase material;

[0143] The desulfurization solid residue is used for preparing a soil remediation agent as an alkaline contaminated soil ecological remediation agent, and the specific components include: desulfurization solid residue 7 parts, red mud 20 parts, wood ash 1.5 parts, and soil 6 parts.

[0144] Through chemical analysis of the desulfurization solid residue, the sulfur retention amount of the desulfurization solid residue is 36.7%, the content of sodium oxide is 0.02%, the content of aluminum oxide is 0.5%, and the water content is 8%.

[0145] Example 4

[0146] The embodiment provides a desulfurizer, and a preparation method thereof includes the following steps:

[0147] S1, the calcium-based solid waste residue slurry is sent into a pre-settling tank, the underflow of the settling tank is sent to an alkali recovery reaction tank and diluted with hot water, and after stirring for 3.5h, a calcium-based solid waste residue slurry reaction liquid is obtained; wherein, the temperature of the calcium-based solid waste residue slurry reaction liquid is 100℃, and the solid-liquid ratio is 0.6;

[0148] S2, the calcium-based solid waste residue slurry reaction liquid is added with a phase change inhibitor to obtain a mixed slurry; wherein the amount of the phase change inhibitor accounts for 0.08% of the total mass of sodium and aluminum in the reaction liquid, and the phase change inhibitor includes calcium gluconate 1 part, cellulose 0.8 part, and wood calcium 2 parts;

[0149] S3, the mixed slurry is subjected to pressure filtration, washing, and re-pressure filtration in a first liquid-solid separation device to obtain a first filtrate and a solid phase material;

[0150] S4, the solid phase material is mixed with water, and a conditioning agent is added at a temperature of 75℃ to obtain a calcium-based solid waste residue slurry desulfurizer with a pH value of 8.1; wherein the mass of the conditioning agent accounts for 0.01% of the total mass of the calcium-based solid waste residue slurry desulfurizer; and the conditioning agent includes sodium citrate 2 parts, trisodium nitrilotriacetate 0.5 part, ethylenediaminetetraacetic acid tetrasodium salt 0.5 part, calcium gluconate and sodium gluconate each 1.2 part, and tannic acid 0.6 part.

[0151] The desulfurizer is used for a desulfurization reaction, which includes the following steps:

[0152] The prepared calcium-based solid waste residue slurry desulfurizer is sent to a desulfurization reactor to perform a reverse desulfurization reaction with 100℃ flue gas to be desulfurized to obtain a desulfurization slurry;

[0153] When the pH value of the desulfurization circulating slurry is lower than 4.8, the desulfurization slurry is sent to a secondary solid-liquid separation device for solid-liquid separation to obtain a desulfurization solution and a desulfurization solid residue.

[0154] The content of sodium and aluminum in the desulfurization solution exceeds 25g / L, the desulfurization solution is reacted with lime at a solid-liquid ratio of 0.01 and a reaction temperature of 40℃ for 5h, and then is sent to a tertiary solid-liquid separation device to obtain a washing water filtrate and a by-product desulfurization solid residue;

[0155] The washing water filtrate is sent to a pre-settling tank, and the by-product desulfurization solid residue and the desulfurization solid residue mixture are used to prepare a soil remediation agent as an alkaline contaminated land soil ecological remediation agent, and the specific components include: desulfurization solid residue and by-product desulfurization solid residue mixture 7 parts, red mud 17 parts, wood ash 2 parts, and soil 2.5 parts.

[0156] Chemical analysis of the desulfurization solid residue shows that the sulfur retention amount of the desulfurization solid residue is 35.5%, the sodium oxide content is 0.018%, the aluminum oxide content is 0.45%, and the water content is 7.5%.

[0157] Example 5

[0158] The embodiment provides a desulfurizer, and the preparation method includes the following steps:

[0159] S1, send the calcium-based solid waste residue slurry into the pre-sedimentation tank, the underflow of the sedimentation tank is sent to the alkali recovery reaction tank and diluted with hot water, and after stirring for 2h, a calcium-based solid waste residue slurry reaction liquid is obtained; wherein the temperature of the calcium-based solid waste residue slurry reaction liquid is 88℃, and the solid-liquid ratio is 0.75;

[0160] S2, a phase change inhibitor is added to the calcium-based solid waste residue slurry reaction liquid to obtain a mixed slurry; wherein the amount of the phase change inhibitor is 0.06% of the total mass of sodium and aluminum in the reaction liquid, and the phase change inhibitor includes calcium gluconate 1.5 parts, cellulose 1.2 parts, wood calcium 1.8 parts, and sodium humate 0.1 part;

[0161] S3, the mixed slurry is subjected to pressure filtration, washing, and re-pressure filtration in a first liquid-solid separation device to obtain a first filtrate and a solid phase material;

[0162] S4, the solid phase material is mixed with water, a temperature control is performed at 68℃, and a conditioning agent is added to obtain a calcium-based solid waste residue slurry desulfurizer with a pH value of 7.6; wherein the mass of the conditioning agent is 0.09% of the total mass of the calcium-based solid waste residue slurry desulfurizer; and the conditioning agent includes sodium citrate 1 part, calcium gluconate and sodium gluconate each 1.2 parts, trisodium nitrilotriacetate 0.5 parts, and ethylenediaminetetraacetic acid disodium magnesium salt 0.9 parts.

[0163] It is used for desulfurization reaction, which includes the following steps:

[0164] The prepared calcium-based solid waste residue slurry desulfurizer is sent to a desulfurization reactor to perform a reverse desulfurization reaction with 70℃ flue gas to be desulfurized to obtain a desulfurization slurry;

[0165] When the pH value of the desulfurization circulating slurry is lower than 4.8, the desulfurization slurry is sent to a secondary solid-liquid separation device for solid-liquid separation to obtain a desulfurization solution and a desulfurization solid residue.

[0166] Wherein, the content of sodium and aluminum in the desulfurization solution exceeds 25g / L, the desulfurization solution is reacted with a mixture of lime 0.5 parts, calcium-silicon slag 1 part, and calcium silicate 0.5 parts, the solid-liquid ratio is 0.15, the reaction temperature is 100℃, and the reaction time is 1h, and after the reaction, it is sent to a tertiary solid-liquid separation device to obtain a washing water filtrate and a by-product desulfurization solid residue;

[0167] The washing water filtrate is sent to a pre-sedimentation tank, and the mixture of by-product desulfurization solid residue and desulfurization solid residue is used to prepare a soil remediation agent as an alkaline contaminated soil ecological remediation agent, and the specific components include: desulfurization solid residue and by-product desulfurization solid residue mixture 5 parts, red mud 13 parts, wood ash 3 parts, and soil 1 part.

[0168] After chemical analysis of the desulfurization solid residue, the calcium-based solid waste residue sulfur fixation amount of the desulfurization solid residue is 37.1%, the sodium oxide content is 0.01%, the aluminum oxide content is 0.39%, and the water content is 7.3%.

[0169] Comparative Example 1

[0170] The present comparative example provides a desulfurizer, the preparation method of which is the same as that in Example 5, except that no phase change inhibitor is added in the present comparative example, and the tempering agent is directly added into the calcium-based solid waste residue slurry reaction solution to obtain a calcium-based solid waste residue slurry desulfurizer;

[0171] The prepared calcium-based solid waste residue slurry desulfurizer is used for a desulfurization reaction, and the reaction steps are the same as those in the desulfurization reaction steps in Example 5. The final results show that the sulfur fixation amount of the desulfurization solid residue in the present comparative example is 22.4%, the sodium oxide content is 1.7%, the aluminum oxide content is 2.5%, and the water content is 20.6%.

[0172] Comparative Example 2

[0173] The present comparative example provides a desulfurizer, the preparation method of which is the same as that in Example 5, except that no tempering agent is added in the present comparative example, and the solid-phase material after filtration of the mixed slurry is mixed with water to obtain a calcium-based solid waste residue slurry desulfurizer;

[0174] The prepared calcium-based solid waste residue slurry desulfurizer is used for a desulfurization reaction, and the reaction steps are the same as those in the desulfurization reaction steps in Example 5. The final results show that the sulfur fixation amount of the desulfurization solid residue in the present comparative example is 26.8%, the sodium oxide content is 0.05%, the aluminum oxide content is 1.2%, and the water content is 25.9%.

[0175] Comparative Example 3

[0176] The present comparative example provides a desulfurizer, the preparation method of which is the same as that in Example 5, except that no phase change inhibitor and tempering agent are added in the present comparative example, and the solid-phase material after solid-liquid separation of the calcium-based solid waste residue slurry reaction solution is mixed with water to obtain a calcium-based solid waste residue slurry desulfurizer;

[0177] The prepared calcium-based solid waste residue slurry desulfurizer is used for a desulfurization reaction, and the reaction steps are the same as those in the desulfurization reaction steps in Example 5. The final results show that the sulfur fixation amount of the desulfurization solid residue in the present comparative example is 20.8%, the sodium oxide content is 2.2%, the aluminum oxide content is 2.8%, and the water content is 37.1%.

[0178] Comparative Example 4

[0179] The present comparative example provides a desulfurizer, the preparation method of which is the same as that in Example 5, except that the mixed slurry obtained by adding the phase change inhibitor in the present comparative example is not subjected to solid-liquid separation, and the tempering agent is directly added to obtain a calcium-based solid waste residue slurry desulfurizer;

[0180] The prepared calcium-based solid waste residue slurry desulfurizer was used for desulfurization reaction, and the reaction steps were the same as those in Example 5. The final results showed that the sulfur retention amount of the desulfurization solid residue in the present comparative example was 27.3%, the sodium oxide content was 0.19%, the aluminum oxide content was 0.78%, and the water content was 9.2%.

[0181] Comparative Example 5

[0182] In the present comparative example, a desulfurizer was provided, and the preparation method included the following steps:

[0183] The calcium-based solid waste residue slurry was sent into a pre-settling tank, and the underflow of the calcium-based solid waste residue slurry was directly subjected to liquid-solid separation. The solid residue obtained by liquid-solid separation was mixed with water to prepare a calcium-based solid waste residue slurry desulfurizer. The liquid-solid ratio was the same as that in Example 5. The above fresh desulfurization slurry was contacted with sulfur-containing flue gas for reaction. Analysis showed that the sulfur retention amount of the desulfurization solid residue in the present comparative example was 15.7%, the sodium oxide content was 2.5%, the aluminum oxide content was 4.7%, and the water content was 55%.

[0184] In summary, Examples 1-5 all used the desulfurizer preparation method provided in the present application to prepare desulfurizers and conduct desulfurization experiments. The results showed that the sulfur retention amount of the desulfurization solid residue was greater than 35%, and the contents of sodium oxide and aluminum oxide were both less than 1%. In Comparative Examples 1-5, however, the desulfurizers were prepared by replacing some of the technical means in Example 5. Compared with Example 5, the sulfur retention amount was lower, and the contents of sodium oxide and aluminum oxide in the desulfurization solid residue were higher. The reasons for this are as follows:

[0185] In the preparation process of the desulfurizer provided in Comparative Example 1, no phase change inhibitor was added, so the composition of the reaction liquid of the calcium-based solid waste residue slurry was not changed. Although a conditioning agent was added, a large amount of aluminum oxide and sodium oxide entered the desulfurization system, and the solid phase material contained calcium aluminate and hydrocalumite, etc. The conditioning effect was limited, thereby affecting the flue gas desulfurization efficiency of the prepared desulfurizer and reducing the sulfur retention amount.

[0186] In the desulfurizer provided in Comparative Example 2, no conditioning agent was added during the preparation process. During the desulfurization process, impurities began to accumulate as the desulfurization reaction proceeded, the filtration performance of the desulfurizer slurry deteriorated, the desulfurization efficiency was affected, the contact area between the desulfurizer slurry and the flue gas was reduced, and the desulfurization performance was reduced, resulting in an increase in the water content of the desulfurization solid residue.

[0187] The preparation method of the desulfurizer provided in Comparative Example 3 includes: the calcium-based solid waste residue slurry underflow is diluted by adding hot water, stirred for 2 hours, and then the obtained calcium-based solid waste residue slurry reaction liquid is separated into solid and liquid phases, and the solid phase material is mixed with water to obtain the desulfurizer. Although the content of sodium oxide in the solid phase material is reduced to a certain extent after the liquid-solid separation of the desulfurizer, the composition of the solid phase material is not changed, and the solid phase material still contains a large amount of calcium aluminate, calcium aluminate hydrate, hydrocalumite, calcium hydroxide, sodium carbonate and sodium hydroxide. When the desulfurizer is used as a desulfurizer for desulfurization reaction, the content of soluble salts in the desulfurization slurry will increase with the continuous desulfurization reaction, the desulfurization slurry is thick, the desulfurization efficiency is low, and the desulfurization performance is poor.

[0188] The desulfurizer provided in Comparative Example 4, because the mixed slurry is not subjected to solid-liquid separation after the phase change inhibitor is added, the aluminum oxide and sodium oxide in the slurry directly enter the desulfurization system. Compared with the embodiment, although the addition of the conditioning agent reduces the influence of aluminum and sodium, the amount of sulfur fixation is still reduced. At the same time, compared with Comparative Example 2, it also shows that the addition of the conditioning agent helps to improve the desulfurization performance of the slurry containing aluminum and sodium impurities, and helps to reduce the moisture content of the desulfurization solid residue.

[0189] The desulfurizer provided in Comparative Example 5 is prepared by mixing the solid phase material obtained by directly subjecting the calcium-based solid waste residue slurry underflow to liquid-solid separation with water. Because the solid residue obtained by liquid-solid separation contains a large amount of calcium aluminate, calcium aluminate hydrate, hydrocalumite, calcium hydroxide, sodium carbonate and sodium hydroxide, the content of soluble salts in the desulfurization slurry will increase, the desulfurization slurry is thick, the desulfurization efficiency is low, the filtration of gypsum is difficult, and the desulfurization performance is poor, and the amount of sulfur dioxide captured is small.

[0190] In summary, the preparation method of the calcium-based solid waste residue slurry desulfurizer provided in the embodiment of the present application includes: subjecting the calcium-based solid waste residue slurry to a settling treatment, sending the settling overflow to an alumina slurry dilution tank, adding hot water and a phase change inhibitor to the settling underflow to obtain a mixed slurry, subjecting the mixed slurry to solid-liquid separation, sending the filtrate to an alumina red mud settling and separation washing system, mixing the filter cake with water and adding a conditioning agent to obtain the calcium-based solid waste residue slurry desulfurizer, and subjecting the calcium-based solid waste residue slurry desulfurizer to a desulfurization reaction with flue gas, and then subjecting the desulfurization slurry to solid-liquid separation to obtain a desulfurization solution and a desulfurization solid residue. The desulfurization solution is subjected to a neutralization reaction treatment and then subjected to solid-liquid separation to obtain a washing water filtrate and a by-product desulfurization solid residue. The desulfurization solid residue and the by-product desulfurization solid residue are used to prepare a soil ecological remediation agent. The calcium-based solid waste residue slurry discharged from the alumina is used to prepare the desulfurizer, which not only recovers the alkali resource and reduces the loss of alumina, but also is used for flue gas desulfurization, realizes the purpose of resource utilization of solid waste, and has the values and significance of pollution reduction, carbon reduction and synergistic effect.

[0191] The foregoing detailed description of the application has been presented for purposes of illustration and description. Various modifications to the description will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other implementations without departing from the spirit or scope of the application. Accordingly, the application is not intended to be limited to the implementations described herein but is to be accorded the widest scope consistent with the principles and novel features to the application.

Claims

1. A method for preparing a calcium-based solid waste slurry desulfurization agent, comprising the following steps: The calcium-based solid waste slurry is settled to obtain the calcium-based solid waste slurry underflow; The calcium-based solid waste slurry underflow is diluted to obtain a calcium-based solid waste slurry reaction solution; the calcium-based solid waste slurry reaction solution contains unstable calcium aluminate, calcium carbonate, calcium aluminate and their hydrates. A phase change inhibitor was added to the calcium-based solid waste slurry reaction solution to obtain a mixed slurry; The mixed slurry was subjected to solid-liquid separation to obtain a solid phase substance; The solid substance is mixed with water and a conditioning agent to obtain a calcium-based solid waste slurry desulfurizing agent; The solid-liquid ratio of the calcium-based solid waste slurry reaction liquid is (0.1-1):1, and the pH value of the calcium-based solid waste slurry desulfurizer is 7-10. The phase change inhibitors include at least three of the following: calcium gluconate, potassium gluconate, cellulose, calcium lignosulfonate, and sodium humate. The conditioning agent includes at least two of citric acid, citrate, gluconate, tannic acid, and aminocarboxylate.

2. According to the preparation method of claim 1, the added mass of the phase change inhibitor accounts for 0.02% to 0.15% of the total mass of sodium and aluminum in the calcium-based solid waste slurry reaction solution.

3. According to the preparation method of claim 1, the mass of the conditioning agent is 0.005% to 0.5% of the total mass of the calcium-based solid waste slurry desulfurizer.

4. A desulfurizing agent, prepared by the method of the calcium-based solid waste slurry desulfurizing agent according to any one of claims 1 to 3.

5. A desulfurization method, comprising the following steps: The calcium-based solid waste slurry desulfurizer as described in claim 4 is obtained; The calcium-based solid waste slurry desulfurizing agent is reacted with the flue gas to be desulfurized to obtain a desulfurized slurry; The pH of the desulfurization reaction is 4.8 to 6.

2.

6. The desulfurization method according to claim 5, after reacting the calcium-based solid waste slurry desulfurizing agent with the flue gas to be desulfurized to obtain a desulfurized slurry, further includes: The desulfurization slurry is subjected to solid-liquid separation to obtain a desulfurization solution and a desulfurization solid residue.

7. The desulfurization method according to claim 6, wherein the desulfurization solution is subjected to a neutralization reaction when the desulfurization solution meets the set conditions, to obtain secondary desulfurization solid slag; The setting conditions include: The total mass concentration of sodium and aluminum in the desulfurization solution is >25 g / L.

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