A method for synergistically treating multi-source solid hazardous waste

Abstract

The application relates to the technical field of solid waste resource recycling, in particular to a method for cooperatively treating multi-source solid hazardous waste; the method is used for cooperatively recycling cold rolling oil sludge, steel slag tailings and waste calcium-based desulfurization catalyst, and the method comprises the following steps: crushing and grinding the waste calcium-based desulfurization catalyst to obtain waste calcium-based desulfurization catalyst powder with a preset particle size; paving the steel slag tailings to obtain a base layer of bedding; alternately laying the cold rolling oil sludge and the waste calcium-based desulfurization catalyst powder on the surface of the base layer of bedding, and then pressing to obtain a composite material pile; standing the composite material pile to obtain a mixed material pile with a preset water content; mixing the steel slag tailings and the mixed material pile to obtain sintering raw materials; the preset particle size is less than or equal to 2 mm; the preset water content is less than or equal to 20%; the thickness ratio of the cold rolling oil sludge layer to the waste calcium-based desulfurization catalyst layer is 2-8; the method can effectively recycle iron, calcium and carbon in the solid hazardous waste in a harmless way, and the overall operation of the method is simple.

Description

Technical Field

[0001] This application relates to the field of solid waste resource recycling technology, and in particular to a method for the co-processing of multi-source solid and hazardous waste. Background Technology

[0002] To ensure a smooth and clean steel plate surface during the cold rolling process, it is generally necessary to lower the rolling temperature to transition from rolling to cold rolling. Additionally, it is crucial to reduce wear on the rolling rolls, which typically requires lubrication with rolling oil. Currently, the main components of cold rolling oil are base oil, emulsifiers, antioxidants, extreme pressure anti-wear agents, rust inhibitors, and defoamers. However, due to repeated rolling, washing, settling, and the influence of impurities in the metal machinery and environmental dust, the components of cold rolling oil gradually oxidize and deteriorate. This deteriorated rolling oil is collected in waste rolling oil collection tanks. After settling, the oil that settles to the bottom becomes cold rolling sludge. Cold rolling sludge is a highly viscous, high-water-content, and complex hazardous waste formed by a mixture of oil, water, and solids. It generally requires specialized treatment companies for harmless disposal, which incurs high disposal costs and carries the risk of potential pollution transfer and tracing. Furthermore, calcium-based fixed-bed desulfurization is an emerging dry desulfurization technology that has been widely applied in environmental protection projects such as coking furnaces, hot blast stoves, and industrial boilers in steel enterprises. This process typically requires the use of shaped granular calcium-based oxidation catalysts. However, after a period of use, these catalysts generate a large amount of waste calcium-based desulfurization catalysts. The main components of these waste catalysts are calcium sulfate, calcium hydroxide, and sodium sulfite. Waste calcium-based desulfurization catalysts are multi-component solid wastes with unstable particle sizes, making them unsuitable for resource utilization. Additionally, with the latest revision of GB 175 "General Silicate Cement" for the building materials industry, waste steel slag is no longer listed as a candidate raw material for cement production admixtures. This cuts off the disposal path for steel slag tailings as cement admixtures, leading to the stockpiling of large amounts of steel slag tailings, which will have a significant adverse impact on the surrounding environment.

[0003] Currently, the recycling of cold-rolled sludge, steel slag tailings, and waste calcium-based desulfurization catalysts is mostly carried out separately. This makes the overall recycling operation quite cumbersome. In addition, there are losses in the overall recycling process, making it difficult to achieve effective recovery of different elements. Summary of the Invention

[0004] This application provides a method for the synergistic treatment of multi-source solid and hazardous waste to address the following technical problem: how to reduce the operational difficulty and losses in the recycling and reuse of cold-rolled sludge, steel slag tailings, and waste calcium-based desulfurization catalysts.

[0005] In a first aspect, this application provides a method for the co-processing of multi-source solid hazardous waste, used for the co-recovery of cold-rolled sludge, steel slag tailings, and waste calcium-based desulfurization catalyst, the method comprising:

[0006] The waste calcium-based desulfurization catalyst is crushed and ground to obtain waste calcium-based desulfurization catalyst powder with a preset particle size;

[0007] The steel slag tailings are spread out to obtain a base layer material;

[0008] The cold-rolled sludge and the waste calcium-based desulfurization catalyst powder with a preset particle size are alternately laid on the surface of the base material, so that the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder form a cold-rolled sludge layer and a waste calcium-based desulfurization catalyst layer respectively, and then pressed to obtain a composite material pile.

[0009] The composite material pile is allowed to stand, allowing the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder to undergo a demulsification reaction, so as to obtain a mixed material pile with a preset moisture content.

[0010] The steel slag tailings and the mixed material pile with a preset moisture content are mixed to obtain sintering raw materials;

[0011] Wherein, the preset particle size is ≤2mm;

[0012] The preset moisture content is ≤20%;

[0013] The thickness ratio of the cold-rolled sludge layer to the waste calcium-based desulfurization catalyst layer is 2 to 8.

[0014] Optionally, the thickness of the cold-rolled sludge layer is 10cm to 15cm, and the thickness of the waste calcium-based desulfurization catalyst layer is 2cm to 5cm.

[0015] Optionally, the method of alternately laying the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder with a preset particle size on the surface of the base material, so that the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder form a cold-rolled sludge layer and a waste calcium-based desulfurization catalyst layer respectively, and then pressing them to obtain a composite stockpile, includes the following steps:

[0016] The cold-rolled sludge is spread evenly on the surface of the base material to obtain a cold-rolled sludge layer;

[0017] The waste calcium-based desulfurization catalyst powder is spread evenly on the surface of the cold-rolled sludge layer to obtain the waste calcium-based desulfurization catalyst layer.

[0018] The cold-rolled sludge and the waste calcium-based desulfurization catalyst powder are alternately laid on the surface of the waste calcium-based desulfurization catalyst layer to obtain a stockpile layer containing multiple layers of cold-rolled sludge and multiple layers of waste calcium-based desulfurization catalyst.

[0019] The stockpile is pressed to obtain a composite stockpile.

[0020] Optionally, the cold-rolled sludge layer has ≥3 layers, and the waste calcium-based desulfurization catalyst layer has ≥2 layers.

[0021] Optionally, the thickness of the composite material pile is 40cm to 55cm; and / or,

[0022] The thickness of the base layer bedding material is 20cm to 30cm.

[0023] Optionally, the preset particle size is ≤1mm; and / or,

[0024] The particle size of the steel slag tailings is ≤5mm.

[0025] Optionally, the settling time is 24h to 72h.

[0026] Optionally, the mass ratio of the steel slag tailings to the mixed material pile is 1:10 to 12.

[0027] Optionally, the chemical composition of the cold-rolled sludge, by mass fraction, includes:

[0028] Oil phase: 25%–35%, solid phase: 30%–45%, and water: 25%–35%; wherein, the solid phase satisfies:

[0029] 50% ≤ TFe ≤ 65%; and / or,

[0030] The chemical composition of the steel slag tailings, by mass fraction, includes:

[0031] CaO: 42%–48%, SiO2: 9%–11%, TFe: 17%–20%, MgO: 11%–13%, Al2O3: 2%–4%, MnO: 3%–5%, P2O5: 2%–3%, and H2O: 2%–7%; and / or,

[0032] The chemical composition of the waste calcium-based desulfurization catalyst, by mass fraction, includes:

[0033] Ca(OH)2: 30%–45%, CaSO4: 35%–45%, CaSO3: 5%–10%, Al2O3: 5%–10%, SiO2: 3%–5%, and H2O ≤1%.

[0034] Optionally, the step of allowing the composite stockpile to stand, allowing the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder to undergo a demulsification reaction to obtain a mixed stockpile with a preset moisture content, includes the following steps:

[0035] The composite material pile is allowed to stand, allowing the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder to undergo a demulsification reaction, so as to obtain waste liquid and a mixed material pile with a preset moisture content, respectively.

[0036] The waste liquid is used as sintering water.

[0037] The technical solutions provided in this application have the following advantages compared with the prior art:

[0038] This application provides a method for the co-processing of multi-source solid and hazardous waste, used for the co-recovery of cold-rolled sludge, steel slag tailings, and waste calcium-based desulfurization catalyst. The method includes: crushing and grinding the waste calcium-based desulfurization catalyst to obtain waste calcium-based desulfurization catalyst powder with a preset particle size; spreading the steel slag tailings to obtain a base layer; and alternately laying the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder with the preset particle size on the surface of the base layer, so that the cold-rolled sludge and the waste calcium-based desulfurization catalyst... The powder is used to form a cold-rolled sludge layer and a waste calcium-based desulfurization catalyst layer, which are then pressed to obtain a composite stockpile. The composite stockpile is then allowed to stand to allow the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder to undergo a demulsification reaction, resulting in a mixed stockpile with a preset moisture content. The steel slag tailings and the mixed stockpile with the preset moisture content are then mixed to obtain sintering raw materials. The preset particle size is ≤2mm, the preset moisture content is ≤20%, and the thickness ratio of the cold-rolled sludge layer to the waste calcium-based desulfurization catalyst layer is 2-8. Waste calcium-based desulfurization catalyst powder with a preset particle size ≤2mm can be obtained by crushing and grinding. This powder provides sufficient Ca(OH)2 components, creating a strongly alkaline environment. In this environment, the abundant Ca(OH)2 can fully demulsify with the oil in cold-rolled sludge, disrupting its water-in-oil structure and allowing the encapsulated water to separate. Furthermore, alternating layers of cold-rolled sludge and waste calcium-based desulfurization catalyst powder, with a thickness ratio of 2–8, further promote the reaction between the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder. Thorough mixing and demulsification of the sulfur catalyst powders ensure complete removal of moisture content and viscosity from the cold-rolled sludge, reducing it to below 20%. This reduced moisture content and viscosity allow the cold-rolled sludge to disperse and coat the waste calcium-based desulfurization catalyst powder on the surface of the steel slag tailings, resulting in a sintering raw material with good permeability. This method effectively and harmlessly recovers iron, calcium, and carbon resources from the cold-rolled sludge, steel slag tailings, and waste calcium-based desulfurization catalysts. Furthermore, the method requires only crushing, leveling, alternating laying, pressing, and settling, making the overall operation simple. Therefore, this method reduces the operational difficulty and losses associated with the recycling of cold-rolled sludge, steel slag tailings, and waste calcium-based desulfurization catalysts. Attached Figure Description

[0039] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This application provides a schematic flowchart of a method for the collaborative treatment of multi-source solid and hazardous waste.

[0042] Figure 2 This application provides a detailed flowchart illustrating a method for the collaborative treatment of multi-source solid and hazardous waste.

[0043] Figure 3 This is a schematic diagram of the microstructure of sintered ore obtained from the sintering of sintering raw materials obtained by a method for co-processing multi-source solid hazardous waste provided in Embodiment 1 of this application. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0045] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that 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., and 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 herein, it means including any referenced number (fraction or integer) within the indicated range.

[0046] In this document, terms such as “comprising” mean “including but not limited to”. Relational terms such as “first” and “second” are used only 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 these entities or operations. “And / or” describes the relationship between related objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone; where A and B can be singular or plural. “At least one” means one or more, “more” means 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 or plural items; for example, “at least one of a, b, or c,” or “at least one of a, b, and c,” can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0047] Figure 1 An exemplary schematic diagram of a method for the collaborative treatment of multi-source solid and hazardous waste is shown in an embodiment of this application;

[0048] like Figure 1 As shown in the embodiments of this application, a method for the co-processing of multi-source solid hazardous waste is provided for the co-recovery of cold-rolled sludge, steel slag tailings, and waste calcium-based desulfurization catalyst. The method includes:

[0049] S1. The waste calcium-based desulfurization catalyst is crushed and ground to obtain waste calcium-based desulfurization catalyst powder with a preset particle size;

[0050] S2. Spread the steel slag tailings evenly to obtain the base layer material;

[0051] S3. The cold-rolled sludge and the waste calcium-based desulfurization catalyst powder with a preset particle size are alternately laid on the surface of the base material, so that the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder form a cold-rolled sludge layer and a waste calcium-based desulfurization catalyst layer respectively, and then pressed to obtain a composite material pile.

[0052] S4. The composite material pile is allowed to stand to allow the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder to undergo a demulsification reaction, so as to obtain a mixed material pile with a preset moisture content.

[0053] S5. The steel slag tailings and the mixed material pile with a preset moisture content are mixed to obtain sintering raw materials;

[0054] Wherein, the preset particle size is ≤2mm;

[0055] The preset moisture content is ≤20%;

[0056] The thickness ratio of the cold-rolled sludge layer to the waste calcium-based desulfurization catalyst layer is 2 to 8;

[0057] In these embodiments, the preset particle size can be ≤2mm, which provides sufficient Ca(OH)2 component. Sufficient Ca(OH)2 component provides a strongly alkaline environment, in which sufficient Ca(OH)2 component can fully demulsify with the oil in the cold-rolled sludge, disrupting the water-in-oil structure of the cold-rolled sludge and allowing the encapsulated water to separate from it. The preset moisture content can be ≤20%, which promotes the dispersion and coating of the cold-rolled sludge and waste calcium-based desulfurization catalyst powder on the surface of the steel slag tailings, resulting in a sintering raw material with good air permeability. This method can effectively and harmlessly recover iron, calcium, and carbon resources from cold-rolled sludge, steel slag tailings, and waste calcium-based desulfurization catalysts. The thickness ratio of the cold-rolled sludge layer to the waste calcium-based desulfurization catalyst layer can be 2 to 8, which can promote thorough mixing between the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder and complete demulsification reaction. This can reduce the moisture content and viscosity of the cold-rolled sludge to below 20%. The cold-rolled sludge with reduced moisture content and viscosity can disperse and coat the waste calcium-based desulfurization catalyst powder on the surface of the steel slag tailings to obtain sintering raw materials with better air permeability.

[0058] The thickness ratio of the cold-rolled sludge layer to the waste calcium-based desulfurization catalyst layer can be 2, 3, 4, 5, 6, 7 or 8.

[0059] It should be noted that the waste calcium-based desulfurization catalyst can be a columnar extruded material with a diameter of 4 mm and a length of 1 cm to 4 cm.

[0060] It should be noted that the steel slag tailings can be a sandy or gravelly solid.

[0061] It should be noted that the cold-rolled oily sludge can be a high-viscosity emulsion mass.

[0062] It should be noted that the steel slag tailings need to be laid flat in the pit that has been treated with three-proof measures before forming the base material.

[0063] In some optional embodiments, the thickness of the cold-rolled sludge layer is 10cm to 15cm, and the thickness of the waste calcium-based desulfurization catalyst layer is 2cm to 5cm;

[0064] In these embodiments, the thickness of the cold-rolled sludge layer can be 10cm to 15cm, and the thickness of the waste calcium-based desulfurization catalyst layer can be 2cm to 5cm. This can further promote thorough mixing between the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder, and ensure complete demulsification reaction. This can further reduce the moisture content and viscosity of the cold-rolled sludge to below 20%. The cold-rolled sludge with reduced moisture content and viscosity can disperse and coat the waste calcium-based desulfurization catalyst powder on the surface of the steel slag tailings to obtain sintering raw materials with better air permeability. Thus, this method can effectively and harmlessly recover iron, calcium, and carbon resources from the cold-rolled sludge, steel slag tailings, and waste calcium-based desulfurization catalyst.

[0065] The thickness of the cold-rolled sludge layer can be 10cm, 11cm, 12cm, 13cm, 14cm or 15cm.

[0066] The thickness of the waste calcium-based desulfurization catalyst layer can be 2cm, 3cm, 4cm or 5cm.

[0067] Figure 2 An exemplary embodiment of this application provides a detailed flowchart of a method for the collaborative treatment of multi-source solid and hazardous waste;

[0068] like Figure 2 As shown, in some optional embodiments, the method of alternately laying the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder with a preset particle size on the surface of the base material, so that the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder form a cold-rolled sludge layer and a waste calcium-based desulfurization catalyst layer respectively, and then pressing them to obtain a composite stockpile, includes the following steps:

[0069] S301. The cold-rolled putty is spread evenly on the surface of the base material to obtain a cold-rolled putty layer;

[0070] S302. The waste calcium-based desulfurization catalyst powder is spread evenly on the surface of the cold-rolled sludge layer to obtain a waste calcium-based desulfurization catalyst layer;

[0071] S303. The cold-rolled sludge and the waste calcium-based desulfurization catalyst powder are alternately laid on the surface of the waste calcium-based desulfurization catalyst layer to obtain a stockpile layer containing multiple layers of cold-rolled sludge and multiple layers of waste calcium-based desulfurization catalyst.

[0072] S304. Press the stockpile layer to obtain a composite stockpile;

[0073] In these embodiments, alternating laying can sequentially form alternating layers of cold-rolled sludge and waste calcium-based desulfurization catalyst on the surface of the base material. This promotes thorough mixing between the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder, as well as complete demulsification reaction. This reduces the moisture content and viscosity of the cold-rolled sludge to below 20%. The cold-rolled sludge with reduced moisture content and viscosity can disperse and coat the waste calcium-based desulfurization catalyst powder on the surface of the steel slag tailings to obtain sintering raw materials with better air permeability. Thus, this method can effectively and harmlessly recover iron, calcium, and carbon resources from the cold-rolled sludge, steel slag tailings, and waste calcium-based desulfurization catalyst.

[0074] In some optional embodiments, the cold-rolled sludge layer has ≥3 layers, and the waste calcium-based desulfurization catalyst layer has ≥2 layers;

[0075] In these embodiments, the number of cold-rolled sludge layers can be ≥3 layers, and the number of waste calcium-based desulfurization catalyst layers can be ≥2 layers. This can promote thorough mixing between the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder, and ensure complete demulsification reaction. This can reduce the moisture content and viscosity of the cold-rolled sludge to below 20%. The cold-rolled sludge with reduced moisture content and viscosity can disperse and coat the waste calcium-based desulfurization catalyst powder on the surface of the steel slag tailings to obtain sintering raw materials with better air permeability.

[0076] In some optional embodiments, the thickness of the composite stockpile is 40cm to 55cm; and / or,

[0077] The thickness of the base layer bedding material is 20cm to 30cm;

[0078] In these embodiments, the thickness of the composite material pile can be 40cm to 55cm, and the thickness of the base layer material can be 20cm to 30cm. This ensures that the composite material pile has sufficient thickness. A sufficiently thick composite material pile can promote thorough mixing between the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder, and complete the demulsification reaction. This can reduce the moisture content and viscosity of the cold-rolled sludge to below 20%. The cold-rolled sludge with reduced moisture content and viscosity can disperse and coat the waste calcium-based desulfurization catalyst powder on the surface of the steel slag tailings to obtain sintering raw materials with better air permeability. In this way, the iron, calcium, and carbon resources in the cold-rolled sludge, steel slag tailings, and waste calcium-based desulfurization catalyst can be effectively and harmlessly recovered.

[0079] The thickness of the composite material pile can be 40cm, 41cm, 42cm, 43cm, 44cm, 45cm, 46cm, 47cm, 48cm, 49cm, 50cm, 51cm, 52cm, 53cm, 54cm or 55cm.

[0080] The thickness of the base layer material can be 20cm, 21cm, 22cm, 23cm, 24cm, 25cm, 26cm, 27cm, 28cm, 29cm or 30cm.

[0081] In some optional embodiments, the preset particle size is ≤1 mm; and / or,

[0082] The particle size of the steel slag tailings is ≤5mm;

[0083] In these embodiments, the preset particle size can be ≤1mm, which can further provide sufficient Ca(OH)2 component. Sufficient Ca(OH)2 component can further provide a strongly alkaline environment. In the strongly alkaline environment, sufficient Ca(OH)2 component can fully demulsify with the oil in the cold-rolled sludge, which can destroy the water-in-oil structure of the cold-rolled sludge, thereby allowing the encapsulated water to be separated from the cold-rolled sludge. In addition, the particle size of the steel slag tailings can be ≤5mm, which can promote the encapsulated water to flow out from the pores of the steel slag tailings into the composite stockpile, thereby obtaining a mixed stockpile with a preset moisture content.

[0084] In some optional embodiments, the settling time is 24h to 72h;

[0085] In these embodiments, the settling time can be 24h to 72h, which can promote the demulsification reaction of the waste calcium-based desulfurization catalyst powder and the grease in the cold-rolled sludge, and can destroy the water-in-oil structure of the cold-rolled sludge, thereby allowing the encapsulated water to be separated from the cold-rolled sludge.

[0086] The resting time can be 24h, 30h, 36h, 42h, 48h, 54h, 60h, 66h or 72h.

[0087] In some optional embodiments, the mass ratio of the steel slag tailings to the mixed stockpile is 1:10 to 12;

[0088] In these embodiments, the mass ratio of steel slag tailings to the mixed material pile can be 1:10 to 12, which can promote the thorough mixing of the mixed material pile and the steel slag tailings, so that the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder can be evenly dispersed and coated on the surface of the steel slag tailings, thereby obtaining sintering raw materials with good air permeability.

[0089] The mass ratio of the steel slag tailings to the mixed material pile can be 1:10, 1:11 or 1:12.

[0090] In some alternative embodiments, the chemical composition of the cold-rolled sludge, by mass fraction, includes:

[0091] Oil phase: 25%–35%, solid phase: 30%–45%, and water: 25%–35%; wherein, the solid phase satisfies:

[0092] 50% ≤ TFe ≤ 65%; and / or,

[0093] The chemical composition of the steel slag tailings, by mass fraction, includes:

[0094] CaO: 42%–48%, SiO2: 9%–11%, TFe: 17%–20%, MgO: 11%–13%, Al2O3: 2%–4%, MnO: 3%–5%, P2O5: 2%–3%, and H2O: 2%–7%; and / or,

[0095] The chemical composition of the waste calcium-based desulfurization catalyst, by mass fraction, includes:

[0096] Ca(OH)2: 30%–45%, CaSO4: 35%–45%, CaSO3: 5%–10%, Al2O3: 5%–10%, SiO2: 3%–5%, and H2O ≤1%;

[0097] In these embodiments, the chemical composition of the cold-rolled sludge may include an oil phase, a solid phase, and water, and the solid phase may satisfy 50% ≤ TFe ≤ 65%, which can promote the cold-rolled sludge to obtain a mixed stockpile with a preset moisture content ≤ 20% after demulsification reaction; in addition, the chemical composition of the waste calcium-based desulfurization catalyst may include Ca(OH)2, CaSO4, CaSO3, Al2O3, SiO2, and H2O, which can promote the waste calcium-based desulfurization catalyst to have sufficient Ca(OH)2 component to form a strongly alkaline environment. In the strongly alkaline environment, sufficient Ca(OH)2 component can... The demulsification reaction between the grease and the cold-rolled sludge can disrupt the water-in-oil structure of the sludge, allowing the encapsulated water to be separated from it. Meanwhile, the chemical composition of the steel slag tailings, which may include CaO, SiO2, Tfe, MgO, Al2O3, MnO, P2O5, and H2O, can effectively serve as a base material to support the cold-rolled sludge and waste calcium-based desulfurization catalyst, thus yielding sintering raw materials. Furthermore, the porous structure of the steel slag tailings can filter the encapsulated water, resulting in waste liquid with little or no solid impurities.

[0098] It should be noted that after the steel slag tailings are filtered and wrapped to form waste liquid, the waste liquid can prevent blockage of the waste liquid in the waste liquid collection tank and during the transportation of the waste liquid through the pipeline. The waste liquid can meet the discharge standards through the sintering process, and the whole method has no wastewater discharge.

[0099] In some optional embodiments, the step of allowing the composite stockpile to stand, allowing the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder to undergo a demulsification reaction to obtain a mixed stockpile with a preset moisture content, includes the following steps:

[0100] S401. The composite material pile is allowed to stand, so that the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder undergo a demulsification reaction to obtain waste liquid and a mixed material pile with a preset moisture content, respectively.

[0101] The waste liquid is used as sintering water;

[0102] In these embodiments, the waste liquid generated by the demulsification reaction can be used as sintering water, thereby further recovering the water in the cold-rolled sludge based on the sintering raw materials prepared from cold-rolled sludge, steel slag tailings and waste calcium-based desulfurization catalyst, thus fully recovering the solid waste components.

[0103] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to industry standards; if no corresponding industry standard exists, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0104] Example 1

[0105] like Figure 2 As shown, a method for the co-processing of multi-source solid and hazardous waste, used for the co-recovery of cold-rolled sludge, steel slag tailings, and spent calcium-based desulfurization catalysts, includes:

[0106] S1. The waste calcium-based desulfurization catalyst is crushed and ground to obtain waste calcium-based desulfurization catalyst powder with a preset particle size;

[0107] S2. Spread the steel slag tailings evenly to obtain the base material;

[0108] S301. Cold-rolled putty is spread evenly on the surface of the base material to obtain a cold-rolled putty layer;

[0109] S302. Waste calcium-based desulfurization catalyst powder is spread evenly on the surface of cold-rolled sludge layer to obtain a waste calcium-based desulfurization catalyst layer;

[0110] S303. Cold-rolled sludge and waste calcium-based desulfurization catalyst powder are alternately laid on the surface of the waste calcium-based desulfurization catalyst layer to obtain a stockpile layer containing multiple layers of cold-rolled sludge and multiple layers of waste calcium-based desulfurization catalyst.

[0111] S304. Compact the stockpile layer to obtain a composite stockpile;

[0112] S401. Allow the composite stockpile to stand still, allowing the cold-rolled sludge and waste calcium-based desulfurization catalyst powder to undergo a demulsification reaction, so as to obtain waste liquid and a mixed stockpile with a preset moisture content, respectively.

[0113] S5. Mix the steel slag tailings and the mixed material with a preset moisture content to obtain sintering raw materials;

[0114] The preset particle size is ≤2mm;

[0115] Preset moisture content ≤20%;

[0116] The thickness ratio of the cold-rolled sludge layer to the waste calcium-based desulfurization catalyst layer is 2;

[0117] The waste liquid is used as sintering water.

[0118] The thickness of the cold-rolled sludge layer is 10cm, and the thickness of the waste calcium-based desulfurization catalyst layer is 5cm.

[0119] The cold-rolled sludge layer has 3 layers, and the waste calcium-based desulfurization catalyst layer has 2 layers.

[0120] The thickness of the composite material pile is 40cm;

[0121] The thickness of the base layer bedding material is 20cm.

[0122] The particle size of steel slag tailings is ≤5mm.

[0123] The settling time is 24 hours.

[0124] The mass ratio of steel slag tailings to the mixed material pile is 1:10.

[0125] The chemical composition of cold-rolled sludge, by mass fraction, includes:

[0126] Oil phase: 35%, solid phase: 30%, and water: 35%; wherein the solid phase satisfies:

[0127] Tfe is 65%;

[0128] The chemical composition of steel slag tailings, by mass fraction, includes:

[0129] CaO: 48%, SiO2: 11%, TFe: 20%, MgO: 11%, Al2O3: 2% ~ 4%, MnO: 3% ~ 5%, P2O5: 2% ~ 3% and H2O: 2% ~ 7%;

[0130] The chemical composition of waste calcium-based desulfurization catalysts, by mass fraction, includes:

[0131] Ca(OH)2: 45%, CaSO4: 35%, CaSO3: 5%, Al2O3: 10%, SiO2: 4%, and H2O: 1%.

[0132] Example 2

[0133] Based on the content disclosed in Example 1, the following operations are further performed:

[0134] Preset particle size ≤1mm;

[0135] Preset moisture content ≤20%;

[0136] The thickness ratio of the cold-rolled sludge layer to the waste calcium-based desulfurization catalyst layer is 3;

[0137] The waste liquid is used as sintering water.

[0138] The thickness of the cold-rolled sludge layer is 15cm, and the thickness of the waste calcium-based desulfurization catalyst layer is 5cm.

[0139] The cold-rolled sludge layer has 3 layers, and the waste calcium-based desulfurization catalyst layer has 2 layers.

[0140] The thickness of the composite material pile is 55cm;

[0141] The thickness of the base layer bedding material is 30cm.

[0142] The settling time is 72 hours.

[0143] The mass ratio of steel slag tailings to the mixed material pile is 1:10.

[0144] The chemical composition of cold-rolled sludge, by mass fraction, includes:

[0145] Oil phase: 25%, solid phase: 40%, and water: 35%; wherein the solid phase satisfies:

[0146] Tfe is 50%;

[0147] The chemical composition of steel slag tailings, by mass fraction, includes:

[0148] CaO: 42%, SiO2: 9%, TFe: 17%, MgO: 13%, Al2O3: 4%, MnO: 5%, P2O5: 3%, and H2O: 7%; and / or,

[0149] The chemical composition of waste calcium-based desulfurization catalysts, by mass fraction, includes:

[0150] Ca(OH)2: 30%, CaSO4: 45%, CaSO3: 10%, Al2O3: 10%, and SiO2: 5%.

[0151] Example 3

[0152] Based on the content disclosed in Example 1, the following operations are further performed:

[0153] Preset particle size ≤2mm;

[0154] Preset moisture content ≤20%;

[0155] The thickness ratio of the cold-rolled sludge layer to the waste calcium-based desulfurization catalyst layer is 4.

[0156] The waste liquid is used as sintering water.

[0157] The thickness of the cold-rolled sludge layer is 12cm, and the thickness of the waste calcium-based desulfurization catalyst layer is 3cm.

[0158] The cold-rolled sludge layer has 3 layers, and the waste calcium-based desulfurization catalyst layer has 2 layers.

[0159] The thickness of the composite material pile is 42cm;

[0160] The thickness of the base layer bedding material is 25cm.

[0161] The particle size of steel slag tailings is ≤5mm.

[0162] The settling time is 48 hours.

[0163] The mass ratio of steel slag tailings to the mixed material pile is 1:12.

[0164] The chemical composition of cold-rolled sludge, by mass fraction, includes:

[0165] Oil phase: 30%, solid phase: 45%, and water: 25%; wherein the solid phase satisfies:

[0166] Tfe is 55%;

[0167] The chemical composition of steel slag tailings, by mass fraction, includes:

[0168] CaO: 45%, SiO2: 10%, TFe: 19%, MgO: 12%, Al2O3: 3%, MnO: 3%, P2O5: 3% and H2O: 5%;

[0169] The chemical composition of waste calcium-based desulfurization catalysts, by mass fraction, includes:

[0170] Ca(OH)2: 40%, CaSO4: 40%, CaSO3: 8%, Al2O3: 8%, SiO2: 3%, and H2O: 1%.

[0171] Comparative Example 1

[0172] Based on the content disclosed in Example 1, the following operations are further performed:

[0173] The thickness ratio of the cold-rolled sludge layer to the waste calcium-based desulfurization catalyst layer is 5.

[0174] The thickness of the cold-rolled sludge layer is 5cm, and the thickness of the waste calcium-based desulfurization catalyst layer is 1cm.

[0175] The cold-rolled sludge layer has two layers, and the waste calcium-based desulfurization catalyst layer has one layer.

[0176] The thickness of the composite material pile is 11cm;

[0177] Comparative Example 2

[0178] Based on the content disclosed in Example 1, the following operations are further performed:

[0179] The thickness ratio of the cold-rolled sludge layer to the waste calcium-based desulfurization catalyst layer is 4:3.

[0180] The thickness of the cold-rolled sludge layer is 20cm, and the thickness of the waste calcium-based desulfurization catalyst layer is 15cm.

[0181] The cold-rolled sludge layer has two layers, and the waste calcium-based desulfurization catalyst layer has one layer.

[0182] The thickness of the composite material pile is 55cm;

[0183] Comparative Example 3

[0184] Based on the content disclosed in Example 1, the following operations are further performed:

[0185] The thickness of the base layer bedding material is 10cm.

[0186] Comparative Example 4

[0187] Based on the content disclosed in Example 1, the following operations are further performed:

[0188] The thickness of the base layer bedding material is 40cm.

[0189] Comparative Example 5

[0190] Based on the content disclosed in Example 1, the following operations are further performed:

[0191] The settling time is 12 hours.

[0192] Comparative Example 6

[0193] Based on the content disclosed in Example 1, the following operations are further performed:

[0194] The settling time is 96 hours.

[0195] Comparative Example 7

[0196] Based on the content disclosed in Example 1, the following operations are further performed:

[0197] The mass ratio of steel slag tailings to the mixed material pile is 1:5.

[0198] Comparative Example 8

[0199] Based on the content disclosed in Example 1, the following operations are further performed:

[0200] The mass ratio of steel slag tailings to the mixed material pile is 1:15.

[0201] Relevant experimental and effect data:

[0202] 1. Figure 3 An exemplary schematic diagram of the microstructure of sintered ore obtained by sintering sintering raw materials from a method for co-processing multi-source solid hazardous waste provided in Embodiment 1 of this application is shown.

[0203] The sintering mixture prepared by the method provided in Example 1 was sintered, and the resulting sinter was subjected to microscopic analysis. The results are as follows: Figure 3 As shown, by Figure 3 It can be seen that calcium ferrite and magnetite are interwoven and embedded in the sinter, and the sinter has high strength.

[0204] 2. The prepared sintering mixed raw materials were added to the sintering ore blend at a weight ratio of 2%, and sintering was carried out under the same operating conditions. The properties of the sintered ore were measured, and the results are shown in Table 1.

[0205] Table 1. Changes in sintering parameters after adding mixed raw materials.

[0206]

[0207] As shown in Table 1, the method for co-processing multi-source solid hazardous waste provided in this application embodiment uses crushing and grinding to obtain waste calcium-based desulfurization catalyst powder with a preset particle size ≤2mm. This waste calcium-based desulfurization catalyst powder with a preset particle size ≤2mm can provide sufficient Ca(OH)2 components. Sufficient Ca(OH)2 components can provide a strongly alkaline environment. In this strongly alkaline environment, sufficient Ca(OH)2 components can fully demulsify with the grease in cold-rolled sludge, destroying the water-in-oil structure of the cold-rolled sludge, thereby separating the encapsulated water from the cold-rolled sludge. Furthermore, the alternating layering of cold-rolled sludge and waste calcium-based desulfurization catalyst powder, and the thickness ratio of the cold-rolled sludge layer to the waste calcium-based desulfurization catalyst layer, can be 2:1. ~8 can promote thorough mixing and complete demulsification reaction between cold-rolled sludge and waste calcium-based desulfurization catalyst powder, thereby reducing the moisture content and viscosity of cold-rolled sludge to below 20%. The cold-rolled sludge with reduced moisture content and viscosity can disperse and coat the waste calcium-based desulfurization catalyst powder on the surface of steel slag tailings to obtain sintering raw materials with better air permeability. In this way, iron, calcium and carbon resources in cold-rolled sludge, steel slag tailings and waste calcium-based desulfurization catalyst can be effectively and harmlessly recovered. In addition, this method only requires crushing, leveling, alternating laying, pressing and settling, and the overall operation is simple. Therefore, this method can reduce the difficulty and loss of recycling cold-rolled sludge, steel slag tailings and waste calcium-based desulfurization catalyst.

[0208] In addition, this application provides a method for the synergistic treatment of multi-source solid hazardous waste. This method utilizes the different physical states (powder, agglomerated, and granular) of three types of solid hazardous waste: cold-rolled sludge, steel slag tailings, and waste calcium-based desulfurization catalyst. The chemical components of the three types of solid hazardous waste are uniformly dispersed through strong mixing. Furthermore, the agglomerated cold-rolled sludge can be dispersed and coated on the surface of the steel slag tailings along with the waste calcium-based desulfurization agent powder, thereby obtaining sintering raw materials with better air permeability. Compared with conventional recycling methods, this method eliminates the conventional sludge dehydration and distillation pretreatment steps, thus enabling the method provided in this application to have the advantages of low energy consumption, no agglomeration, convenient processing, and low cost.

[0209] In addition, this application provides a method for the synergistic treatment of multi-source solid and hazardous waste. The raw materials prepared by this method can not only meet the requirements of sintering production, but also recover iron, calcium and carbon resources in solid and hazardous waste in a resource-efficient and harmless manner, thereby reducing the cost and environmental risks associated with the disposal of additional solid and hazardous waste.

[0210] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A method for the co-processing of multi-source solid and hazardous waste, used for the co-recovery of cold-rolled sludge, steel slag tailings, and spent calcium-based desulfurization catalyst, characterized in that, The method includes: The waste calcium-based desulfurization catalyst is crushed and ground to obtain waste calcium-based desulfurization catalyst powder with a preset particle size; The steel slag tailings are spread out to obtain a base layer material, the thickness of which is 20cm to 30cm. The cold-rolled sludge and the waste calcium-based desulfurization catalyst powder with a preset particle size are alternately laid on the surface of the base material, so that the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder form a cold-rolled sludge layer and a waste calcium-based desulfurization catalyst layer respectively. Then, they are pressed to obtain a composite material pile. The number of cold-rolled sludge layers is ≥3 layers and the number of waste calcium-based desulfurization catalyst layers is ≥2 layers. The composite material pile is allowed to stand for 24 hours to 72 hours to allow the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder to undergo a demulsification reaction, thereby obtaining a mixed material pile with a preset moisture content. The steel slag tailings and the mixed material pile with a preset moisture content are mixed to obtain sintering raw materials; Wherein, the preset particle size is ≤1mm; The preset moisture content is ≤20%; The thickness ratio of the cold-rolled sludge layer to the waste calcium-based desulfurization catalyst layer is 2 to 8; The mass ratio of the steel slag tailings to the mixed material pile is 1:10-12; The chemical composition of the cold-rolled sludge, by mass fraction, includes: Oil phase: 25%–35%, solid phase: 30%–45%, and water: 25%–35%; wherein, the solid phase satisfies: 50%≤TFe≤65%; and / or, The chemical composition of the steel slag tailings, by mass fraction, includes: CaO: 42%–48%, SiO2: 9%–11%, TFe: 17%–20%, MgO: 11%–13%, Al2O3: 2%–4%, MnO: 3%–5%, P2O5: 2%–3%, and H2O: 2%–7%; and / or, The chemical composition of the waste calcium-based desulfurization catalyst, by mass fraction, includes: Ca(OH)2: 30%~45%, CaSO4: 35%~45%, CaSO3: 5%~10%, Al2O3: 5%~10%, SiO2: 3%~5% and H2O≤1%.

2. The method according to claim 1, characterized in that, The thickness of the cold-rolled sludge layer is 10cm to 15cm, and the thickness of the waste calcium-based desulfurization catalyst layer is 2cm to 5cm.

3. The method according to claim 1, characterized in that, The method involves alternately laying the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder with a preset particle size on the surface of the base material, so that the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder form a cold-rolled sludge layer and a waste calcium-based desulfurization catalyst layer, respectively, and then pressing them to obtain a composite stockpile, including the following steps: The cold-rolled sludge is spread evenly on the surface of the base material to obtain a cold-rolled sludge layer; The waste calcium-based desulfurization catalyst powder is spread evenly on the surface of the cold-rolled sludge layer to obtain the waste calcium-based desulfurization catalyst layer. The cold-rolled sludge and the waste calcium-based desulfurization catalyst powder are alternately laid on the surface of the waste calcium-based desulfurization catalyst layer to obtain a stockpile layer containing multiple layers of cold-rolled sludge and multiple layers of waste calcium-based desulfurization catalyst. The stockpile is pressed to obtain a composite stockpile.

4. The method according to claim 1 or 3, characterized in that, The thickness of the composite material pile is 40cm to 55cm.

5. The method according to claim 1, characterized in that, The particle size of the steel slag tailings is ≤5mm.

6. The method according to claim 1, characterized in that, The step of allowing the composite stockpile to stand, allowing the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder to undergo a demulsification reaction to obtain a mixed stockpile with a preset moisture content, includes the following steps: The composite material pile is allowed to stand, allowing the cold-rolled sludge and the waste calcium-based desulfurization catalyst powder to undergo a demulsification reaction, so as to obtain waste liquid and a mixed material pile with a preset moisture content, respectively. The waste liquid is used as sintering water.

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