Resource utilization method of waste calcium-based dry desulfurization agent

Abstract

The invention relates to a resource utilization method of a waste calcium-based dry desulfurizer, and belongs to the technical field of solid waste resource utilization, the method comprises the following steps: separating the waste calcium-based dry desulfurizer to obtain a first material containing calcium oxide and calcium hydroxide and a second material containing calcium sulfite and calcium sulfate; mixing the second material, a reinforcing agent and a solvent to obtain a third material; molding the third material to obtain molded particles; grinding the first material and a calcium oxide-containing material to obtain a fourth material; and coating the fourth material on the surfaces of the formed particles, and curing to obtain the secondary calcium-based dry desulfurization agent. And carrying out desulfurization reaction on the secondary calcium-based dry desulfurization agent to obtain a fifth material containing calcium sulfite and calcium sulfate. The second material is used for preparing the inner core of the desulfurizing agent, so that the investment of new raw materials for preparing the desulfurizing agent is reduced, the purity of calcium sulfate is improved after the secondary dry desulfurizing agent loses efficacy, and the calcium sulfate can be directly used as a papermaking raw material to replace part of paper pulp.

Description

Technical Field

[0001] The present application relates to the technical field of resource utilization of solid waste, and in particular to a resource utilization method of a waste calcium-based dry desulfurization agent. Background Art

[0002] Calcium-based dry desulfurization is a process that mainly involves chemical reactions between calcium-containing absorbents and sulfur dioxide in flue gas to generate solid calcium sulfate to remove sulfur dioxide from flue gas. Because it does not require liquid absorbents, it avoids wastewater treatment problems, has simple equipment operation, is easy to operate and maintain, and occupies a small area, it has been widely used in steel companies' coking furnaces, hot blast furnaces, and industrial boiler environmental protection projects.

[0003] At present, the shaped granular calcium-based oxidation catalyst used in this process generates a large amount of waste calcium-based desulfurization catalyst after a period of use, the main components of which are calcium sulfate, calcium hydroxide, and sodium sulfite; due to CaO and Ca(OH) 2 The molar volume is small, once it is combined with SO 2 The reaction produces CaSO 3 and CaSO 4 After that, the molar volume of the desulfurizer increases rapidly, blocking the pores of the desulfurizer, causing the desulfurization efficiency to decrease, and even the desulfurization reaction is difficult to continue. As a multi-component, large-particle, and unstable solid waste, the waste calcium-based dry desulfurizer faces the problem of being unable to be recycled. Summary of the invention

[0004] The present application provides a method for resource utilization of waste calcium-based dry desulfurization agent to solve the following technical problem: how to effectively utilize waste calcium-based dry desulfurization agent.

[0005] In a first aspect, the present application provides a method for resource utilization of waste calcium-based dry desulfurization agent, the method comprising:

[0006] The waste calcium-based dry desulfurizer is separated to obtain CaO and Ca(OH) 2 The first material and the CaSO 3 With CaSO 4 the second material;

[0007] The second material, the enhancer and the solvent are mixed to obtain a third material;

[0008] forming the third material to obtain formed particles;

[0009] Grinding the first material and the calcium oxide-containing material to obtain a fourth material;

[0010] The fourth material is coated on the surface of the shaped particles and solidified to obtain a secondary calcium-based dry desulfurization agent.

[0011] Optionally, the reinforcing agent includes at least one of the following: water glass, bentonite, cement, and epoxy resin.

[0012] Optionally, the mass ratio of the second material, the enhancer and the solvent is (75-85):(12-19):(4-6).

[0013] Optionally, the reinforcing agent includes water glass and bentonite, and the mass ratio of the water glass to the bentonite is (4-7):(8-12).

[0014] Optionally, the weight ratio of the first material to the calcium oxide-containing material is (4.5-5.5):(4.5-5.5).

[0015] Optionally, the final particle size of the grinding is 200-300 mesh.

[0016] Optionally, the coating has a thickness of 2 mm to 3 mm.

[0017] Optionally, the curing temperature is 110°C to 130°C.

[0018] Optionally, the separation includes shaking and screening; wherein,

[0019] The process parameters of the oscillation include: an amplitude height of 4 mm to 6 mm, a frequency of 180 times / min to 200 times / min, and a time of 5 min to 10 min.

[0020] Optionally, the method further comprises: subjecting the calcium-based dry desulfurizer to a desulfurization reaction to obtain a desulfurization agent containing CaSO 3 With CaSO 4 The fifth material; wherein the CaSO 4 The quality is greater than 80%.

[0021] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0022] The resource utilization method of the waste calcium-based dry desulfurization agent provided in the embodiment of the present application comprises: separating the waste calcium-based dry desulfurization agent to obtain a mixture containing CaO and Ca(OH) 2 The first material and the CaSO 3 With CaSO 4The second material is mixed with the second material, the reinforcing agent and the solvent to obtain a third material; the third material is molded to obtain molded particles; the first material and the calcium oxide-containing material are ground to obtain a fourth material; the fourth material is coated on the surface of the molded particles and solidified to obtain a secondary calcium-based dry desulfurizer. The surface layer of the waste calcium-based dry desulfurizer is CaSO 3 With CaSO 4 , the interior is CaO and Ca(OH) 2 , the waste calcium-based dry desulfurizer is separated to obtain CaO and Ca(OH) 2 The first material and the CaSO 3 With CaSO 4 The second material is mixed with the reinforcing agent and the solvent to obtain a strong shaped particle; the first material and the calcium oxide-containing material are ground to obtain a fourth material as a desulfurizer; the shaped particle is used as the core, and the fourth material is coated on the surface of the shaped particle to obtain a secondary calcium-based dry desulfurizer. The secondary calcium-based dry desulfurizer can be used for dry desulfurization again. The outer layer of the calcium-based dry desulfurizer CaO and Ca(OH) 2 Absorbing sulfur dioxide, calcium-based dry desulfurizer can be converted into CaSO 3 With CaSO 4 mixture to achieve full recycling of waste calcium-based dry desulfurization agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0025] Figure 1 A schematic flow chart of a method for resource utilization of a waste calcium-based dry desulfurizer provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0027] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have 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, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0028] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present application specification, the terms "include", "comprise", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, wherein a, b, c can be single or multiple, respectively. In the proportional relationship involved in this article, the parameters that need to be described by proportion should be understood as the first term of the proportional formula according to the order of description, and the proportional numbers should be understood as the second term of the proportional formula. 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 correspond one by one to the proportional numbers in the proportional formula according to the order of description, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0029] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0030] Waste calcium-based dry desulfurizer mainly contains calcium compounds. Its surface is CaSO 3 (Calcium sulfite) and CaSO 4 (calcium sulfate), which contains CaO (calcium oxide) and Ca(OH) 2 (Calcium hydroxide). These components are formed during the desulfurization process. During the desulfurization reaction, CaO and Ca(OH) in the calcium-based desulfurizer 2 SO in exhaust gas 2 Reacts to generate CaSO 3 and CaSO 4 For example, Ca(OH) 2 +SO 2 =CaSO 3 +H 2 O, 2CaSO 3 +O 2 =2CaSO 4 Structure: This component distribution structure is caused by the desulfurization reaction process. During the desulfurization process, the sulfur dioxide in the exhaust gas first contacts the outer layer of the desulfurizer, causing the CaO and Ca(OH) 2 The preferred reaction is to form CaSO 3 and CaSO 4 , while the internal CaO and Ca(OH) 2 The desulfurization process progresses, and the active components of the desulfurizer (CaO and Ca(OH) 2 ) gradually decreases, and the desulfurization efficiency decreases. When the desulfurization performance of the desulfurizer drops to a certain level and it is difficult to meet the emission standards or industrial production requirements, it will be discarded. In addition, the desulfurizer may agglomerate and wear during use, which will also lead to its abandonment. If a large amount of waste calcium-based dry desulfurizer is not recycled, a large amount of land will be occupied for stacking, and the calcium compounds in it may enter the soil and water bodies with rainwater erosion, causing environmental problems such as soil salinization and water pollution. For example, CaSO 4 Excessive accumulation of such substances in the soil will cause soil compaction, affecting the air permeability and water permeability of the soil. Recycling waste calcium-based dry desulfurizer can reduce the production cost of enterprises. By recycling waste calcium-based dry desulfurizer, the use of new desulfurizer can be reduced, and certain economic benefits can also be obtained from the recycled desulfurizer.

[0031] Therefore, in the first aspect, the present application provides a method for resource utilization of waste calcium-based dry desulfurization agent. Figure 1 A schematic diagram of a method for resource utilization of a waste calcium-based dry desulfurizer provided in an embodiment of the present application; see Figure 1 , the method comprising:

[0032] S1. Separate the waste calcium-based dry desulfurizer to obtain CaO and Ca(OH) 2 The first material and the CaSO 3 With CaSO 4 the second material;

[0033] In some embodiments, the separation comprises shaking and sieving; wherein,

[0034] The process parameters of the oscillation include: an amplitude height of 4 mm to 6 mm, a frequency of 180 times / min to 200 times / min, and a time of 5 min to 10 min.

[0035] In the embodiment of the present application, the waste calcium-based dry desulfurization agent is separated to obtain CaO and Ca(OH) 2 The first material and the CaSO 3 With CaSO 4 This precise separation lays the foundation for subsequent targeted treatment, effectively distinguishing calcium-based components in different chemical states, and avoiding the mixing of components during subsequent processing that affects the performance of the final product. The separation includes shaking and screening, and the above-screen portion is mainly unreacted CaO and Ca(OH) 2 The first material, the undersize part is mainly CaSO generated by desulfurization reaction. 3 and CaSO 4 The process parameters of the oscillation are as follows: the amplitude height can be 4mm to 6mm, the frequency can be 180 times / min to 200 times / min, and the time can be 5min to 10min, which can fully realize the separation of CaO and Ca(OH) 2 and CaSO 3 and CaSO 4 For example, the amplitude height can be 4 mm, 5 mm, 6 mm, etc.; the frequency can be 180 times / min, 185 times / min, 190 times / min, 195 times / min, 200 times / min, etc.; the time can be 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, etc.

[0036] S2, mixing the second material, the enhancer and the solvent to obtain a third material;

[0037] S3, shaping the third material to obtain shaped particles;

[0038] In some embodiments, the reinforcing agent includes at least one of the following: water glass, bentonite, cement, and epoxy resin.

[0039] In some embodiments, the mass ratio of the second material, the enhancer and the solvent is (75-85):(12-19):(4-6).

[0040] In some embodiments, the reinforcing agent includes water glass and bentonite, and the mass ratio of the water glass to the bentonite is (4-7):(8-12).

[0041] In the embodiment of the present application, the second material is mixed with a reinforcing agent and a solvent to form a third material. The reinforcing agent can improve the strength of the particles; the solvent assists in mixing and bonding, allowing the material to be formed, thereby preparing a core with a certain mechanical strength to ensure that it will not be easily broken during subsequent use and maintain a stable physical structure. The reinforcing agent can be a combination of one or more of water glass, bentonite, cement, and epoxy resin. The mixing and stirring can be carried out for 20 minutes to 40 minutes in step S2.

[0042] The mass ratio of the second material, the enhancer and the solvent can be (75-85):(12-19):(4-6). The second material, as the main component, plays the role of the main structure in the formed particles. It is separated from the surface of the waste calcium-based dry desulfurizer and contains calcium sulfite (CaSO 3 ) and calcium sulfate (CaSO 4 ), there is enough calcium salt component in the third material to provide a stable core foundation for the subsequent coating process. The role of the reinforcing agent is to improve the strength of the molded particles. The reinforcing agent can effectively interact with the second material and the solvent, fully allowing the subsequent molded particles to reach sufficient strength to avoid breakage during subsequent processing, transportation or use, and reasonably consider the interaction with other ingredients, which is beneficial to subsequent coating and desulfurization reactions. The solvent mainly plays a role of mixing and bonding. An appropriate amount of solvent can make the second material and the reinforcing agent fully mixed and uniform, ensuring the uniformity of the composition of the molded particles. Exemplarily, the mass ratio of the second material, the reinforcing agent and the solvent can be 75:12:4, 85:19:6, 80:15:5, 79:13:6, etc.

[0043] The reinforcing agent may include water glass and bentonite. Water glass can increase the bonding force between particles, allowing the molded particles to be more closely combined, thereby forming a more solid molded particle. It can also form a hardened film on the surface of the molded particles, increase the hardness and durability of the particles, thereby improving the compressive strength of the molded particles and avoiding the breakage and damage of the molded particles during transportation and storage. Bentonite can be used as an adhesive. It has high stability and bonding force at high temperatures, and the raw materials are cheap, which can greatly improve the quality of the pellets. The sodium silicate in the water glass can react with carbon dioxide in the air to form a silica gel, and finally form a network of silica gel, which is coated on the surface of the particles to enhance the strength of the pellets. Bentonite has high water absorption, and when it meets water, it produces a certain strength that can destroy the hydration film in the water glass to turn it into a viscous liquid or semi-solid, and finally form a hydrated glass or vitreous body with a certain strength. Water glass and bentonite are combined and mixed into the second material to further strengthen the strength of the inner core and improve the product quality of the third material. The mass ratio of water glass to bentonite can be (4-7): (8-12), taking into account the strength and cost of the third material after molding. Exemplarily, the mass ratio of water glass to bentonite can be 4:8, 6:11, 7:12, 6:9, etc. The molding can be prepared into a shaped particle sphere with a diameter of 5-7 mm by a spherical granulator, and dried at 110-130° C. for 40-60 minutes.

[0044] S4, grinding the first material and the calcium oxide-containing material to obtain a fourth material;

[0045] In some embodiments, the weight ratio of the first material to the calcium oxide-containing material is (4.5-5.5):(4.5-5.5).

[0046] In the embodiment of the present application, the calcium oxide-containing material mainly provides calcium oxide components to absorb sulfur dioxide in the flue gas, further improving the desulfurization capacity of the first material. The calcium oxide in the calcium oxide-containing material will expand during the desulfurization process, and the surface of the desulfurizer will continue to powder and peel off, solving the problem of blockage of the desulfurizer pores and inability to react inside after the simple calcium hydroxide reaction. The calcium oxide-containing material can be pure calcium oxide or quicklime. Calcium oxide (CaO) is a strong alkaline substance with high chemical activity in the desulfurization process and can quickly react with sulfur dioxide (SO 2 ) reaction; Ca(OH) 2 The same alkaline substances can also participate in the desulfurization reaction. In this weight ratio range, the fourth material mixture contains an appropriate amount of CaO and Ca(OH) 2, so that after the fourth material is coated on the surface of the formed particles, it can continuously and stably provide chemically active sites during the desulfurization process to ensure the efficient desulfurization reaction. At the same time, it avoids the high CaO content, which may cause the reaction to be too violent. In local areas, agglomeration may occur due to excessive release of reaction heat, affecting the service life and desulfurization effect of the desulfurizer; if the CaO content is low, the reaction activity may be insufficient, and it is difficult to effectively convert sulfur dioxide into calcium sulfite and calcium sulfate. The appropriate weight ratio of the first material to the calcium oxide-containing material can make the ground material have good particle size and fluidity, which is convenient for coating on the surface of the formed particles. However, it is not advisable to add too much calcium oxide-containing material, which may cause the desulfurizer to have too high a pulverization rate and too large a desulfurization resistance. Exemplarily, the weight ratio of the first material to the calcium oxide-containing material can be 4.5:5.5, 5:5, 5.5:5.5, etc.

[0047] In some embodiments, the final particle size of the grinding is 200-300 mesh.

[0048] In the embodiment of the present application, the terminal particle size of the grinding is 200 mesh to 300 mesh, which can increase the reaction surface area of ​​the fourth material and improve the desulfurization efficiency. "Mesh" is a unit used to measure the size of particles. It represents the number of mesh holes on a one-inch (25.4 mm) long sieve. 200 mesh means that there are 200 mesh holes on a one-inch long sieve. The larger the mesh number, the smaller the sieve hole, and accordingly, the smaller the particle size that can pass through the sieve. Exemplarily, the terminal particle size of the grinding can be 200 mesh, 250 mesh, or 300 mesh.

[0049] S5. Coating the fourth material on the surface of the shaped particles and solidifying them to obtain a secondary calcium-based dry desulfurization agent.

[0050] In some embodiments, the coating has a thickness of 2 mm to 3 mm.

[0051] In the embodiment of the present application, the fourth material is coated on the surface of the formed particles. The fourth material is used as the raw material for the desulfurization reaction, and the formed particles are used as the core aggregate to support the strength of the fourth material. The coating thickness is 2mm to 3mm, which can ensure that there is a sufficient amount of active desulfurization components (CaO and Ca(OH) 2 ) covers the surface of the formed particles. In the dry desulfurization process, sulfur dioxide needs to contact the surface of the desulfurizer to react. The 2mm to 3mm coating layer provides a sufficient reaction interface. It will not cause insufficient reaction materials and insufficient desulfurization due to being too thin, nor will it cause material waste due to being too thick, so that the outer layer of CaO and Ca(OH) 2 It can efficiently capture sulfur dioxide and convert it into CaSO 3 With CaSO 4, maintaining a stable and good desulfurization efficiency. Appropriate thickness helps to maintain the physical integrity of the molded particles and takes into account the cost. Therefore, keeping it within this thickness range can not only achieve the ideal desulfurization effect and particle stability, but also reasonably control the amount of raw materials. Exemplarily, the thickness of the coating can be 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, etc. The coating can use a spray granulator to evenly wrap the fourth material in the prepared molded particle spheres. Compared with the traditional extrusion-molded dry desulfurizer, the secondary calcium-based desulfurizer has more abundant micropores inside, which can promote the desulfurization reaction from the outside to the inside, and the desulfurization efficiency is higher.

[0052] In some embodiments, the curing temperature is 110°C to 130°C.

[0053] In the embodiment of the present application, the curing temperature may be 110°C to 130°C, which can further maintain the dry bulb strength and avoid cracking and breaking due to excessive temperature. Exemplarily, the curing temperature may be 110°C, 115°C, 120°C, 125°C, 130°C, etc.

[0054] In some embodiments, the method further comprises: subjecting the secondary calcium-based dry desulfurization agent to a desulfurization reaction to obtain a CaSO 3 With CaSO 4 The fifth material; wherein the CaSO 4 The quality is greater than 80%.

[0055] In the embodiment of the present application, since the calcium-based dry desulfurization process is limited to the inside of the desulfurizer and it is difficult to react, the undersize part (second material) is used to prepare the desulfurizer core, which can not only reduce the input of new raw materials for preparing the desulfurizer, but also make the CaSO 4 The purity is improved and it can be directly used as papermaking raw material to replace part of the pulp. 4 The content is greater than 80%, and it can be directly used as a papermaking raw material to replace part of the pulp. The chemical composition of the above waste calcium-based dry desulfurizer includes: Ca(OH) 2 , CaO, CaSO 4 、CaSO 3 、Al 2 O 3 、SiO 2 and H 2 O; of which, by mass, 30 parts ≤ Ca(OH) 2 +CaO≤45 parts, 35 parts≤CaSO 4 ≤45 parts, 5 parts ≤CaSO 3 ≤10 parts, 5 parts≤Al 2 O 3≤10 parts, 3 parts≤SiO 2 ≤5 parts, H 2 O≤1 part; particle size characteristic is columnar extruded material with diameter 4mm and length 1-4cm.

[0056] The resource utilization method of the waste calcium-based dry desulfurization agent provided in the embodiment of the present application has the following advantages:

[0057] 1. According to the distribution characteristics of the waste calcium-based dry desulfurizer, it is split into the first material (containing CaO and Ca(OH) 2 ) and the second material (containing CaSO 3 With CaSO 4 ). This separation operation allows different materials to go to different processing flows, avoiding mutual interference between components during subsequent processing, and paving a reasonable starting point for the entire resource utilization process;

[0058] 2. For CaSO 3 With CaSO 4 The second material is added with a reinforcing agent and a solvent and mixed to form a shaped particle. The reinforcing agent gives the particle sufficient mechanical strength to withstand friction, impact and other external forces in subsequent processing, transportation and desulfurization use scenarios; the solvent promotes the uniform blending of various components to ensure that the particle texture is uniform and the subsequent coating process is carried out in a stable core form;

[0059] 3. The first material and the calcium oxide-containing material are ground to form the fourth material. This process not only reduces the particle size, but also activates the desulfurization potential of the material. Grinding and refining allow CaO and Ca(OH) 2 Greater exposure greatly expands the specific surface area, and after subsequent coating, it can serve as an outer layer desulfurizer, more efficiently capturing sulfur dioxide and greatly improving desulfurization activity;

[0060] 4. The fourth material containing active desulfurization ingredients is coated on the surface of the formed particles and then solidified, which cleverly combines the structural support of the inner core with the desulfurization activity of the outer layer, so that the secondary calcium-based dry desulfurizer has both a stable physical structure and strong chemical efficiency; 5. The secondary calcium-based dry desulfurizer is put into the dry desulfurization operation, and the outer layer CaO and Ca(OH) 2 Reacts with sulfur dioxide to generate CaSO 3 With CaSO 4 , achieving the transformation of waste calcium-based dry desulfurizer from waste to usable resources. This not only reduces environmental disposal costs, but also avoids the energy consumption and costs of mining and producing new desulfurizer raw materials.

[0061] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for the unrecorded specific conditions in the following examples are usually measured according to national standards. If there is no corresponding national standard, then carry out according to general international standards, normal conditions or according to the conditions recommended by the manufacturer.

[0062] Example 1

[0063] The raw materials are prepared according to the following mass percentage: The chemical composition of the waste calcium-based desulfurization catalyst is: Ca(OH) 2 35%, CaO10%, CaSO 4 35%, CaSO 3 5%, Al 2 O 3 10%, SiO 2 4%, H 2 O1%.

[0064] 1) Place the waste calcium-based dry desulfurizer in a sieve shaker and shake for 5 minutes. The amplitude of the sieve shaker is 4 mm and the frequency is 200 times / min.

[0065] 2) After the shock, the spent catalyst is screened through a 2mm sieve and divided into two parts. The part above the sieve is mainly unreacted CaO and Ca(OH) 2 The undersize part is mainly CaSO generated by desulfurization reaction. 3 and CaSO 4 powder.

[0066] 3) The sieve portion was mixed with water glass, bentonite and water in a mass ratio of 80:5:10:5 and stirred for 20 minutes, and then prepared into spheres with a diameter of 5 mm by a spherical granulator, and dried at 120° C. for 50 minutes.

[0067] 4) The oversize portion and quicklime were ball-milled to 200 mesh in a mass ratio of 4.5:5. to obtain a mixed powder.

[0068] 5) The mixed powder is evenly coated on the prepared spheres by a spray granulator. The coating thickness is controlled to be 2 mm and then dried at 120° C. for 30 min to obtain a secondary calcium-based dry desulfurizer. The sulfur capacity is tested to be 16.9%, which can be used in the dry desulfurization process.

[0069] 6) Secondary calcium-based dry desulfurizer that fails again after use, CaSO 4 The content is 80%. After being ground into powder, the desulfurizer can be directly used as a papermaking raw material to replace part of the pulp to produce high-quality paper and improve the quality and glossiness of the paper.

[0070] Example 2

[0071] The raw materials are prepared according to the following mass percentage: The chemical composition of the waste calcium-based desulfurization catalyst is: Ca(OH) 2 26%, CaO4%, CaSO 4 45%, CaSO 3 10%, Al 2 O 3 10%, SiO 2 4%, H 2 O1%.

[0072] 1) Place the waste calcium-based dry desulfurizer in a sieve shaker and shake for 8 minutes. The amplitude of the sieve shaker is 6 mm and the frequency is 180 times / min.

[0073] 2) After the shock, the spent catalyst is screened through a 2mm sieve and divided into two parts. The part above the sieve is mainly unreacted CaO and Ca(OH) 2 The undersize part is mainly CaSO generated by desulfurization reaction. 3 and CaSO 4 powder.

[0074] 3) The sieve portion was mixed with water glass, bentonite and water in a mass ratio of 80:5:10:5 and stirred for 30 minutes, and then prepared into spheres with a diameter of 6 mm by a spherical granulator, and dried at 120° C. for 50 minutes.

[0075] 4) The oversize portion and quicklime are ball-milled to 250 mesh in a mass ratio of 5.5:4.5 to obtain a mixed powder.

[0076] 5) The mixed powder is evenly coated on the prepared spheres by a spray granulator. The coating thickness is controlled to be 2 mm and then dried at 120° C. for 30 min to obtain a secondary calcium-based dry desulfurizer. The sulfur capacity is tested to be 17.3%, which can be used in the dry desulfurization process.

[0077] 6) Secondary calcium-based dry desulfurizer that fails again after use, CaSO 4 The content is 82%. After being ground into powder, the desulfurizer can be directly used as a papermaking raw material to replace part of the pulp to produce high-quality paper and improve the quality and glossiness of the paper.

[0078] Example 3

[0079] The raw materials are prepared according to the following mass percentage: The chemical composition of the waste calcium-based desulfurization catalyst is: Ca(OH) 2 34%, CaO6%, CaSO 4 40%, CaSO 3 8%, Al 2 O 3 8%, SiO2 3%、H 2 O1%.

[0080] 1) Place the waste calcium-based dry desulfurizer in a sieve shaker and shake for 10 minutes. The amplitude of the sieve shaker is 5 mm and the frequency is 190 times / min.

[0081] 2) After the shock, the spent catalyst is screened through a 2mm sieve and divided into two parts. The part above the sieve is mainly unreacted CaO and Ca(OH) 2 The undersize part is mainly CaSO generated by desulfurization reaction. 3 and CaSO 4 powder.

[0082] 3) The sieve portion was mixed with water glass, bentonite and water in a mass ratio of 80:5:10:5 and stirred for 40 minutes, and then prepared into spheres with a diameter of 7 mm by a spherical granulator, and dried at 120° C. for 50 minutes.

[0083] 4) The oversize portion and quicklime were ball-milled into 300 meshes in a mass ratio of 5:5 to obtain a mixed powder.

[0084] 5) The mixed powder is evenly coated on the prepared spheres by a spray granulator. The coating thickness is controlled to be 3 mm and then dried at 120° C. for 30 min to obtain a secondary calcium-based dry desulfurizer. The sulfur capacity is tested to be 18.2%, which can be used in the dry desulfurization process.

[0085] 6) Secondary calcium-based dry desulfurizer that fails again after use, CaSO 4 The content is 85%. After being ground into powder, the desulfurizer can be directly used as a papermaking raw material to replace part of the pulp to produce high-quality paper and improve the quality and glossiness of the paper.

[0086] Comparative Example 1

[0087] The raw materials are prepared according to the following mass percentage: The chemical composition of the waste calcium-based desulfurization catalyst is: Ca(OH) 2 34%, CaO6%, CaSO 4 40%, CaSO 3 8%, Al 2 O 3 8%, SiO 2 3%、H 2 O1%.

[0088] 1) The waste calcium-based dry desulfurizer and quicklime were ball-milled into 300 meshes in a mass ratio of 8:2 to obtain a mixed powder.

[0089] 2) The mixed powder is mixed with water glass, bentonite and water in a mass ratio of 80:5:10:5 and stirred for 40 minutes, and then prepared into spheres with a diameter of 10 mm by a spherical granulator, and dried at 120°C for 50 minutes to obtain a secondary calcium-based dry desulfurizer. The sulfur capacity is tested to be 9.5%, which is used for dry desulfurization process. The desulfurization efficiency is low and the failure is fast.

[0090] 3) Secondary calcium-based dry desulfurizer that fails again after use, CaSO 4 The content is 65%. Due to the complex composition and unstable proportion of the waste desulfurizer, it is difficult to control the quality of paper products and it cannot be used in the papermaking process.

[0091] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0092] (1) The embodiment of the present application first uses a physical method to classify the components in the waste desulfurizer, and then uses the characteristics of different components to prepare a secondary calcium-based dry desulfurizer. While fully utilizing solid waste as a resource, there is no need to invest in the construction of large-scale equipment. The treatment method is simple, useful calcium-based resources are recovered, and good technical and economic benefits are achieved;

[0093] (2) The secondary calcium-based dry desulfurizer provided in the embodiment of the present application is a mixture of calcium sulfate and calcium sulfite, which can be converted into calcium sulfate after simple oxidation, thereby changing from a multi-component mixture into a recyclable resource;

[0094] (3) After simple vibration screening of the calcium-based desulfurizer, the above-screen portion can be mainly composed of unreacted CaO and Ca(OH) 2 The undersize part is mainly CaSO generated by desulfurization reaction. 3 and CaSO 4 The separation of powder between the two;

[0095] (4) Compared with the traditional extruded dry desulfurizer, the new generation of calcium-based desulfurizer has more micropores inside, which can promote the desulfurization reaction from the outside to the inside, and the desulfurization efficiency is higher;

[0096] (5) Since the calcium-based dry desulfurization process is limited to the desulfurizer and it is difficult to react, the undersize part (second material) is used to prepare the desulfurizer core, which can not only reduce the input of new raw materials for the preparation of desulfurizer, but also make the CaSO 4 With improved purity, it can be directly used as raw material for papermaking, replacing part of the pulp.

[0097] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for resource utilization of waste calcium-based dry desulfurization agent, the method comprising: Separating the waste calcium-based dry desulfurizer to obtain a first material containing CaO and Ca(OH)2 and a second material containing CaSO3 and CaSO4; The second material, the enhancer and the solvent are mixed to obtain a third material; forming the third material to obtain formed particles; Grinding the first material and the calcium oxide-containing material to obtain a fourth material; The fourth material is coated on the surface of the shaped particles and solidified to obtain a secondary calcium-based dry desulfurization agent.

2. The method according to claim 1, characterized in that The reinforcing agent includes at least one of the following: water glass, bentonite, cement, and epoxy resin.

3. The method according to claim 2, characterized in that The mass ratio of the second material, the enhancer and the solvent is (75-85):(12-19):(4-6).

4. The method according to claim 2 or 3, characterized in that: The reinforcing agent comprises water glass and bentonite, and the mass ratio of the water glass to the bentonite is (4-7):(8-12).

5. The method according to claim 1, characterized in that The weight ratio of the first material to the calcium oxide-containing material is (4.5-5.5):(4.5-5.5).

6. The method according to claim 1, characterized in that The final particle size of the grinding is 200-300 meshes.

7. The method according to claim 1, characterized in that The coating thickness is 2 mm to 3 mm.

8. The method according to claim 1 or 7, characterized in that: The curing temperature is 110°C to 130°C.

9. The method according to claim 1, characterized in that: The separation includes shaking and screening; wherein, The process parameters of the oscillation include: an amplitude height of 4 mm to 6 mm, a frequency of 180 times / min to 200 times / min, and a time of 5 min to 10 min.

10. The method according to claim 1, characterized in that The method further comprises: The secondary calcium-based dry desulfurizer is subjected to a desulfurization reaction to obtain a fifth material containing CaSO3 and CaSO4; wherein the mass of the CaSO4 is greater than 80%.

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