Process for producing coagulant by comprehensive utilization of polyaluminum waste residue resources

Abstract

The application discloses a process for producing a coagulant by comprehensively utilizing polyaluminum waste residues, and the process comprises the following steps: improving the acid condition of polyaluminum waste residues by calcium oxide; obtaining a coagulant precursor liquid by crushing the mixture, magnetic powder and water; obtaining a coagulant liquid by performing polymerization activation and then magnetization reaction on the coagulant precursor liquid; obtaining a solidified coagulant by allowing the coagulant liquid to be still and mature; and crushing the solidified coagulant into a required particle size after flash drying, so that the solidified coagulant can be sold, and the polyaluminum waste residues are utilized.

Description

Technical Field

[0001] This invention belongs to the field of polyaluminum waste recycling, specifically relating to a process for the comprehensive utilization of polyaluminum waste resources to produce coagulants. Background Technology

[0002] The commonly used method for producing polyaluminum chloride (PAC) in China is a two-step process using bauxite (activated kaolin), calcium aluminate powder, and hydrochloric acid. Under certain conditions, bauxite and calcium aluminate powder are reacted with hydrochloric acid to obtain PAC liquid. The remaining solid waste that cannot be dissolved by acid is the waste residue generated during the PAC production process. Because a small amount of polyaluminum remains in the waste residue, it is also called polyaluminum waste residue.

[0003] Currently, most of these waste residues are transported to landfills for deep burial or, following the Chinese patent CN109351762A "A Harmless Treatment System and Process for Polyaluminum Chloride Water Purifier Waste Residue," are treated to render the waste harmless before stockpiling. These stockpiling methods not only occupy large amounts of land and cause environmental pollution, but also prevent the rational utilization of usable components in the waste residue, resulting in resource waste and severely limiting the further development of the water purification agent industry. Therefore, continuously exploring new utilization pathways for polyaluminum chloride waste residue, and developing methods that can consume it in large quantities, is currently the main trend in its utilization. Because PAC waste residue has a certain degree of weak acidity and a Cl- content as high as 8.85%, it cannot be directly used as a building material. Furthermore, although the SiO2 and Al2O3 contents in PAC waste residue are not low, at 34.74% and 22.55% respectively, the chemical activity of SiO2 and Al2O3 is not well utilized in an acidic environment, thus greatly limiting the utilization of PAC waste residue. There are few existing studies on the resource utilization of polyaluminum chloride waste residue as raw material. Summary of the Invention

[0004] To address the shortcomings described in the prior art, this invention provides a process for the comprehensive utilization of polyaluminum waste to produce coagulants, wherein the polyaluminum waste is subjected to polymerization activation treatment, magnetization, and maturation to obtain the coagulant.

[0005] The technical solution adopted in this invention is as follows: A process for the comprehensive utilization of polyaluminum oxide waste to produce coagulants includes the following steps: S1, wet polyaluminum waste residue is flash dried to obtain polyaluminum waste residue with a moisture content of 5%; S2, dried polyaluminum waste residue is mixed with calcium oxide and then crushed to obtain a crushed mixture; A primary mixture is obtained by mixing polyaluminum waste with a moisture content of 5% with calcium oxide with a content of more than 97%. By weight, the ratio of polyaluminum waste to calcium oxide is 75:25. A crushed mixture is obtained by crushing a primary mixture. S3, the crushed mixture undergoes activation and magnetization reactions to obtain a coagulant liquid; Polymerization activation reaction: The crushed mixture and magnetic powder are mixed to obtain a magnetic mixture, with the ratio of crushed mixture to magnetic powder being 20:1 by weight. The magnetic mixture was prepared and its Baume degree was controlled at 45 degrees. The purpose of adding magnetic powder was to increase the positive charge and enhance the magnetism of the mixture, which would facilitate polymerization and accelerate the reaction rate.

[0006] The magnetic mixture was subjected to a polymerization activation reaction to obtain an activated coagulant liquid. The reaction temperature was 90°C - 95°C and the activation time was 5 hours. Magnetization reaction: The activated coagulant liquid was subjected to a magnetization reaction for 5 hours, with a magnetization voltage of 36V. S4, the coagulant liquid is statically aged to obtain solidified coagulant, and the aging time is 24 hours; S5, the solidified coagulant is flash-dried, and the moisture content of the coagulant after drying is 5%-8%; S6, crush the dried coagulant.

[0007] As a preferred embodiment of the present invention, the moisture content of the wet polyaluminum waste residue is 40%; the primary mixture is crushed to 200 mesh; and the coagulant is crushed to 180-200 mesh.

[0008] As a preferred embodiment of the present invention, the wet polyaluminum waste residue is put into a flash evaporator for drying, and after drying, the polyaluminum waste residue is transported to a coarse slag storage bin for storage and future use. After drying, the polyaluminum oxide waste and calcium oxide are mixed in a mixer. The mixture is fed into a vertical crusher for crushing, and the crushed mixture is then transported to a storage bin for later use. The flash evaporator, coarse slag storage silo, mixing mixer and vertical crusher are all equipped with dust collection pipes, and each dust collection pipe is connected to a bag filter; the dust in the dust collection pipe is discharged after being cleaned by the bag filter. The crushed mixture and magnetic powder are added to the polymerization reactor, and process water is introduced into the polymerization reactor for mixing and stirring to control the Baume degree in the polymerization reactor; steam is introduced into the polymerization reactor to raise the temperature of the mixture to 95°C and maintain it at 90°C-95°C to activate the mixture in the polymerization reactor. After polymerization activation is completed, a magnetization reaction is carried out. Conductive rods are distributed around the polymerization reaction tank. A voltage of 36V is provided to the conductive rods to magnetize the coagulant in the polymerization reaction tank. The reaction time is 5 hours. The exhaust gas from the polymerization reactor is cleaned by an exhaust gas scrubbing device. The scrubbing water from the exhaust gas scrubbing device is then supplied to the polymerization reactor for reuse, and the cleaned exhaust gas is discharged. The magnetized coagulant liquid is transported to a storage chamber for static curing, which solidifies the coagulant liquid. The curing time is 24 hours. The solidified coagulant is then transported to a flash evaporator for drying, and the moisture content of the dried coagulant is 5%-8%. After drying, the coagulant is crushed by a vertical crusher to the target particle size; The flash evaporator and vertical crusher are equipped with dust collection pipes, which are connected to a bag filter. After crushing, the coagulant is packaged and sold using a packaging machine.

[0009] This invention improves the acidic conditions of polyaluminum waste residue with calcium oxide, crushes the mixture, and then adds magnetic powder and water to obtain a pre-coagulant liquid. The pre-coagulant liquid is polymerized and activated, and then magnetized to obtain a coagulant liquid. After static curing, the coagulant liquid is solidified and then flash-dried and crushed into the required particle size for sale, thus realizing the resource utilization of polyaluminum waste residue. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a system flowchart of the present invention. Detailed Implementation

[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] Example: A process for the comprehensive utilization of polyaluminum oxide waste to produce coagulants, such as... Figure 1 As shown, the steps are as follows: S1, wet polyaluminum waste residue is flash dried to obtain polyaluminum waste residue with a moisture content of 5%; Wet polyaluminum waste with a moisture content of about 40% is fed into the hopper of a flash evaporator using equipment such as a loader. Then, it is metered and fed into the flash evaporator by a screw conveyor for drying to obtain polyaluminum waste with a moisture content of 5%. After drying, the polyaluminum waste is transported to a coarse slag storage silo for storage and later use. Dust generated at the flash evaporator and coarse slag storage silo is collected by dust collection pipes and then discharged after being cleaned by a bag filter. S2, dried polyaluminum waste residue is mixed with calcium oxide and then crushed to obtain a crushed mixture; A primary mixture is obtained by mixing polyaluminum waste with a moisture content of 5% and calcium oxide with a content of more than 97% in a mixer. By weight, the ratio of polyaluminum waste to calcium oxide is 75:25. The mixture is fed into a vertical crusher for crushing to 200 mesh, and then the crushed mixture is sent to a storage bin for storage. Dust generated at the mixing mixer and vertical crusher is collected by dust collection pipes and then discharged after being cleaned by a bag filter. S3, the crushed mixture undergoes activation and magnetization reactions to obtain a coagulant liquid; Polymerization activation reaction: The crushed mixture and magnetic powder are added to the polymerization reactor and mixed to obtain a magnetic mixture. By weight, the ratio of crushed mixture to magnetic powder is 20:1. Process water is introduced into the polymerization reactor and mixed with the magnetic mixture to obtain a magnetic mixture, and the Baume degree of the magnetic mixture is controlled at 45 degrees. Steam is introduced into the polymerization reactor to raise the temperature of the mixture to 95°C and maintain it at 90°C-95°C to activate the mixture in the polymerization reactor for 5 hours. After polymerization activation is complete, a magnetization reaction is carried out: The polymerization reactor is surrounded by conductive rods. A 36V voltage is supplied to the conductive rods to magnetize the coagulant inside the polymerization reactor. The reaction time is 5 hours. The magnetization voltage is used to step down the mains power to a safe 36V voltage via a transformer.

[0014] The exhaust gas from the polymerization reactor is cleaned by an exhaust gas scrubbing device. The scrubbing water from the exhaust gas scrubbing device is then supplied to the polymerization reactor for reuse, and the cleaned exhaust gas is discharged. S4, the coagulant liquid is transported to the storage silo for static curing to obtain solidified coagulant, the curing time is 24 hours; S5, the solidified coagulant is transported to the flash evaporator for flash drying. After drying, the moisture content of the coagulant is 5%-8%. The dust generated at the flash evaporator is collected by the dust collection pipe and discharged after being cleaned by the bag filter. S6, crush the dried coagulant.

[0015] After drying, the coagulant is crushed by a vertical crusher to 180-200 mesh. The dust generated at the vertical crusher is collected by a dust collection pipe and then discharged after being cleaned by a bag filter. After crushing, the coagulant is packaged and sold using a packaging machine.

[0016] In this specification, the terms "an embodiment," "example," "specific example," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0017] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A process for producing coagulants by comprehensive utilization of polyaluminum waste residue resources, characterized in that, The steps are as follows: S1, wet polyaluminum waste residue is flash dried to obtain polyaluminum waste residue with a moisture content of 5%; S2, dried polyaluminum waste residue is mixed with calcium oxide and then crushed to obtain a crushed mixture; A primary mixture is obtained by mixing polyaluminum waste with a moisture content of 5% with calcium oxide with a content of more than 97%. By weight, the ratio of polyaluminum waste to calcium oxide is 75:

25. A crushed mixture is obtained by crushing a primary mixture. S3, the crushed mixture undergoes activation and magnetization reactions to obtain a coagulant liquid; Polymerization activation reaction: The crushed mixture and magnetic powder are mixed to obtain a magnetic mixture, with the ratio of crushed mixture to magnetic powder being 20:1 by weight. Prepare a magnetic mixture and control the Baume degree of the magnetic mixture at 45 degrees. The magnetic mixture was subjected to a polymerization activation reaction to obtain an activated coagulant liquid. The reaction temperature was 90°C - 95°C and the activation time was 5 hours. Magnetization reaction: The activated coagulant liquid was subjected to a magnetization reaction for 5 hours, with a magnetization voltage of 36V. S4, the coagulant liquid is allowed to stand and mature to obtain a solidified coagulant; S5, the solidified coagulant is flash-dried, and the moisture content of the coagulant after drying is 5%-8%; S6, crush the dried coagulant.

2. The process for the comprehensive utilization of polyaluminum waste residue to produce coagulants according to claim 1, characterized in that: The moisture content of wet polyaluminum waste residue is 40%; the primary mixture is crushed to 200 mesh; the coagulant is crushed to 180-200 mesh.

3. The process for the comprehensive utilization of polyaluminum waste residue to produce coagulants according to claim 1 or 2, characterized in that: The wet polyaluminum waste residue is fed into a flash evaporator for drying. After drying, the polyaluminum waste residue is transported to a coarse slag storage silo for storage and future use. After drying, the polyaluminum oxide waste and calcium oxide are mixed in a mixer. The mixture is fed into a vertical crusher for crushing, and the crushed mixture is then transported to a storage bin for later use. The crushed mixture and magnetic powder are added to the polymerization reactor, and process water is introduced into the polymerization reactor for mixing and stirring to control the Baume degree in the polymerization reactor; steam is introduced into the polymerization reactor to raise the temperature of the mixture to 95°C and maintain it at 90°C-95°C for activation reaction; The polymerization reactor has several conductive rods. A voltage of 36V is provided to the conductive rods to magnetize the coagulant inside the polymerization reactor. The coagulant liquid is transported to a storage silo for static curing, allowing the coagulant liquid to solidify. The solidified coagulant is then transported to a flash evaporator for drying, and the moisture content of the dried coagulant is 5%-8%. The dried coagulant is crushed using a vertical crusher; The flash evaporator and vertical crusher are equipped with dust collection pipes, which are connected to a bag filter. After crushing, the coagulant is packaged and sold using a packaging machine.

4. The process for the comprehensive utilization of polyaluminum waste residue to produce coagulants according to claim 3, characterized in that: The flash evaporator, coarse slag storage silo, mixing mixer, and vertical crusher are all equipped with dust collection pipes, each of which is connected to a bag filter. The exhaust gas from the polymerization reactor is cleaned by an exhaust gas scrubbing device, and the scrubbing water from the exhaust gas scrubbing device is supplied to the polymerization reactor for reuse. The cleaned exhaust gas is then discharged. The flash evaporator and vertical crusher are equipped with dust collection pipes, which are connected to a bag filter.

Images