Method for resource utilization of red mud and paint slag

Abstract

The application discloses a method for resource utilization of red mud and paint residue, and belongs to the field of waste resource utilization. The method utilizes pyrolysis gas of the paint residue to reduce the red mud, can obtain synthetic gas H2 and CO while magnetically selecting ferromagnetic materials from the reduced red mud. The method simultaneously utilizes the harmful resources of the red mud and the paint residue, can harmlessly and resourcefully utilize a large amount of the red mud and the automobile paint residue, realizes the purpose of treating waste with waste and changing waste into treasure while protecting the environment, and provides a new method for solid waste resourceful treatment.

Description

Technical Field

[0001] This invention relates to a method for the resource utilization of red mud and paint residue, belonging to the field of waste resource utilization. Background Technology

[0002] With the rapid development of my country's alumina industry, the production of red mud has also increased rapidly. Although the utilization rate of red mud is gradually improving, a large amount of red mud remains stockpiled. Exposed red mud easily forms dust, which is carried by the wind and causes air pollution. This pollution seriously damages the ecological environment and has an adverse impact on the survival of humans, animals, and plants. As more and more red mud accumulates, it endangers the development of the alumina industry and causes continuous harm to human society.

[0003] Paint residue is a hazardous waste containing a large amount of volatile organic compounds. If not properly disposed of, it will not only have a huge impact on health, but also damage the ecological environment and hinder sustainable development.

[0004] Because both red mud and paint residue are hazardous wastes, their resource utilization is urgently needed. While many methods exist for the resource utilization of red mud, most processes are complex and energy-intensive. Furthermore, the use of numerous additives not only increases processing costs but also potentially causes secondary environmental pollution. Moreover, current technologies lack methods for simultaneously processing red mud and paint residue; separate processing significantly increases costs. Therefore, a method capable of simultaneously processing both red mud and paint residue is urgently needed. Summary of the Invention

[0005] To effectively utilize both red mud and paint residue simultaneously, this invention provides a method for the resource utilization of red mud and paint residue. In this method, red mud is reduced using pyrolysis gas from paint residue, allowing for the magnetic separation of ferromagnetic materials from the reduced red mud while simultaneously obtaining syngas. The specific process is as follows:

[0006] (1) Dry the red mud, grind it, and roast it for later use.

[0007] (2) The red mud obtained in step 1 is spread on the quartz wool 2 of the suspension device, and the paint residue is placed in the quartz crucible 1 of the suspension device. The suspension device is fixed in the reactor by the suspension ring 4 to carry out the reaction. When the reaction occurs, under the heat preservation effect of the heat preservation plug 3, the paint residue in the quartz crucible 1 is pyrolyzed. The pyrolysis atmosphere moves upward and comes into contact with the red mud on the quartz wool 2 and reacts. The reaction is divided into heating and heat preservation processes. The heating process is carried out in a closed manner. During the heat preservation process, the gas outlet of the reactor is opened and connected to the gas washing, drying and dust removal device to collect the synthesis gas. After the heat preservation ends and the reactor cools down, the reduced red mud is obtained.

[0008] (3) The reduced red mud obtained in step (2) is subjected to magnetic separation to extract iron from the red mud.

[0009] Preferably, the suspension device includes a quartz crucible 1, quartz wool 2, heat-insulating plug 3, suspension ring 4, high-temperature resistant tungsten wire 5, fixing ring I 6, and fixing ring II 7;

[0010] Quartz crucible 1, quartz wool 2, heat insulation plug 3, suspension ring 4, fixing ring I 6, and fixing ring II 7 are connected by high-temperature resistant tungsten wire 5. Quartz crucible 1 is connected to the bottom of high-temperature tungsten wire 5. Fixing ring II 7 is connected to the upper part of quartz crucible 1. Suspension ring 4 is installed at the top of high-temperature tungsten wire 5. Heat insulation plug 3 is connected to the bottom of suspension ring 4. Fixing ring I 6 is connected to the bottom of heat insulation plug 3. Quartz wool is connected between heat insulation plug 3 and quartz crucible 1.

[0011] Preferably, the paint residue is one of oil-based dry paint residue or oil-based wet paint residue.

[0012] Preferably, the red mud is Bayer process red mud.

[0013] Preferably, the synthesis gas includes CO and H2.

[0014] Preferably, the roasting temperature in step (1) is 200℃~1000℃ and the roasting time is 30min~60min.

[0015] Preferably, the amount of paint residue used in step (2) is 20% to 100% of the amount of red mud used.

[0016] Preferably, the reactor in step (2) is a vertical tube furnace.

[0017] Preferably, in step (2), the heating rate is 5℃ / min to 10℃ / min, the holding temperature is 800℃ to 1200℃, and the holding time is 30min to 60min.

[0018] The paint residue mentioned in this invention refers to the waste residue generated during the painting process.

[0019] The beneficial effects of this invention are:

[0020] (1) The present invention can effectively utilize a large amount of stockpiled red mud, extract iron from red mud and reduce the waste of iron resources, while realizing the resource utilization of hazardous waste paint residue and obtaining syngas energy.

[0021] (2) This invention can render large amounts of red mud and paint residue harmless and resource-based, and achieve waste-to-waste treatment while protecting the environment, providing a new method for the resource-based treatment of solid waste in my country.

[0022] (3) This invention only uses red mud and paint residue, without the need to add other substances, thus saving processing costs.

[0023] (4) The suspension device provided by the present invention can effectively realize the resource utilization of red mud and paint residue. Attached Figure Description

[0024] Appendix Figure 1 A process flow diagram for the pyrolysis gas reduction of red mud from automotive paint residue to extract iron and generate syngas.

[0025] Appendix Figure 2 This is a schematic diagram of the suspension device.

[0026] Appendix Figure 3 The images show the XRD patterns of the red mud before and after the reaction in Example 2.

[0027] In the diagram: 1-quartz crucible, 2-quartz wool, 3-insulating plug, 4-suspension ring, 5-high temperature resistant tungsten wire, 6-fixing ring I, 7-fixing ring II Detailed Implementation

[0028] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following embodiments are merely simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0029] Example 1

[0030] A method for the resource utilization of red mud and paint residue specifically includes the following steps:

[0031] (1) Dry the red mud, grind it, and calcine it at 200℃ for 60 minutes before use;

[0032] (2) Spread the red mud obtained in step (1) evenly on the quartz wool of the suspension device, and place the oil-based wet paint residue in the quartz crucible of the suspension device, wherein the amount of oil-based wet paint residue is 20% of the amount of red mud. The suspension device is fixed in the reactor by the suspension ring for reaction. When the reaction occurs, under the heat preservation effect of the heat preservation and plugging pipe, the paint residue in the quartz crucible pyrolyzes, and the pyrolysis atmosphere moves upward and comes into contact with the red mud on the quartz wool and reacts. The reactor heating rate is 10℃ / min. After the temperature is closed and heated to the reaction temperature of 1200℃, the gas outlet valve is opened and the reaction is carried out for 30 minutes. The gas outlet of the reactor is connected to a gas washing, drying and dust removal device to collect the synthesis gas H2 and CO. After the heat preservation ends and the reactor cools down, the reduced red mud is obtained.

[0033] (3) Magnetic separation is performed on the reduced red mud to extract iron from the red mud.

[0034] The H2 yield in the synthesis gas was measured to be 0.41 g / L (g is the mass of oil-based wet paint residue), and the CO yield was 0.22 g / L.

[0035] Example 2

[0036] A method for the resource utilization of red mud and paint residue specifically includes the following steps:

[0037] (1) Dry the red mud, grind it, and calcine it at 400℃ for 30 minutes before use;

[0038] (2) The red mud obtained in step (1) is spread evenly on the quartz wool of the suspension device. The oil-based wet paint residue is placed in the quartz crucible of the suspension device, wherein the amount of oil-based wet paint residue is 50% of the amount of red mud. The suspension device is fixed in the reactor by the suspension ring for reaction. When the reaction occurs, under the heat preservation effect of the heat preservation and plugging pipe, the paint residue in the quartz crucible is pyrolyzed. The pyrolysis atmosphere moves upward and comes into contact with the red mud on the quartz wool and reacts. The reactor heating rate is 10℃ / min. After the temperature is closed and heated to the reaction temperature of 1000℃, the gas outlet valve is opened and the reaction is carried out for 60min. The gas outlet of the reactor is connected to a gas washing, drying and dust removal device to collect the synthesis gas H2 and CO. After the heat preservation ends and the reactor cools down, the reduced red mud is obtained.

[0039] (3) Magnetic separation is performed on the reduced red mud to extract iron from the red mud.

[0040] The syngas yield was measured to be 0.62 g / L (g represents the mass of oil-based wet paint residue) and 0.38 g / L. Example 2 showed the highest syngas yield. The XRD patterns of the red mud before and after the reaction in Example 2 are shown below. Figure 3 As shown in the figure, Fe2O3 in the red mud is reduced to magnetic Fe3O4.

[0041] Example 3

[0042] A method for the resource utilization of red mud and paint residue specifically includes the following steps:

[0043] (1) Dry the red mud, grind it, and calcine it at 600℃ for 30 minutes before use;

[0044] (2) Spread the red mud obtained in step (1) evenly on the quartz wool of the suspension device, and place the oil-based dry paint residue in the quartz crucible of the suspension device. The amount of oil-based wet paint residue is 100% of the amount of red mud. The suspension device is fixed in the reactor by the suspension ring for reaction. When the reaction occurs, under the heat preservation effect of the heat preservation and plugging, the paint residue in the quartz crucible is pyrolyzed. The pyrolysis atmosphere moves upward and comes into contact with the red mud on the quartz wool and reacts. The reactor heating rate is 5℃ / min. After the temperature is closed and heated to the reaction temperature of 1200℃, the gas outlet valve is opened and the reaction is carried out for 60min. The gas outlet of the reactor is connected to a gas washing, drying and dust removal device to collect the synthesis gas H2 and CO. After the heat preservation ends and the reactor cools down, the reduced red mud is obtained.

[0045] (3) Magnetic separation is performed on the reduced red mud to extract iron from the red mud.

[0046] The H2 yield in the synthesis gas was measured to be 0.51 g / L (g represents the mass of oil-based wet paint residue), and the CO yield was 0.32 g / L.

[0047] Example 4

[0048] A method for the resource utilization of red mud and paint residue specifically includes the following steps:

[0049] (1) Dry the red mud, grind it, and calcine it at 800℃ for 30 minutes before use;

[0050] (2) The red mud obtained in step (1) is spread evenly on the quartz wool of the suspension device. The oil-based wet paint residue is placed in the quartz crucible of the suspension device, wherein the amount of oil-based wet paint residue is 50% of the amount of red mud. The suspension device is fixed in the reactor by the suspension ring for reaction. When the reaction occurs, under the heat preservation effect of the heat preservation and plugging pipe, the paint residue in the quartz crucible is pyrolyzed. The pyrolysis atmosphere moves upward and comes into contact with the red mud on the quartz wool and reacts. The reactor heating rate is 10℃ / min. After the temperature is closed and heated to the reaction temperature of 1000℃, the gas outlet valve is opened and the reaction is carried out for 60min. The gas outlet of the reactor is connected to a gas washing, drying and dust removal device to collect the synthesis gas H2 and CO. After the heat preservation ends and the reactor cools down, the reduced red mud is obtained.

[0051] (3) Magnetic separation is performed on the reduced red mud to extract iron from the red mud.

[0052] The H2 yield in the synthesis gas was measured to be 0.28 g / L (g is the mass of oil-based wet paint residue), and the CO yield was 0.20 g / L.

[0053] Example 5

[0054] A method for the resource utilization of red mud and paint residue specifically includes the following steps:

[0055] (1) Dry the red mud, grind it, and calcine it at 1000℃ for 30 minutes before use;

[0056] (2) Spread the red mud obtained in step (1) evenly on the quartz wool of the suspension device, and place the oil-based wet paint residue in the quartz crucible of the suspension device, wherein the amount of oil-based wet paint residue is 100% of the amount of red mud. The suspension device is fixed in the reactor by the suspension ring for reaction. When the reaction occurs, under the heat preservation effect of the heat preservation and plugging pipe, the paint residue in the quartz crucible is pyrolyzed, and the pyrolysis atmosphere moves upward and comes into contact with the red mud on the quartz wool and reacts. The reactor heating rate is 10℃ / min. After the temperature is closed and heated to the reaction temperature of 800℃, the gas outlet valve is opened and the reaction is carried out for 60min. The gas outlet of the reactor is connected to a gas washing, drying and dust removal device to collect the synthesis gas H2 and CO. After the heat preservation ends and the reactor cools down, the reduced red mud is obtained.

[0057] (3) Magnetic separation is performed on the reduced red mud to extract iron from the red mud.

[0058] The H2 yield in the synthesis gas was measured to be 0.26 g / L (g represents the mass of oil-based wet paint residue), and the CO yield was 0.16 g / L.

Claims

1. A method for the resource utilization of red mud and paint residue, characterized in that: By reducing red mud with pyrolysis gas from paint slag, ferromagnetic materials can be obtained from the reduced red mud through magnetic separation, while simultaneously generating syngas. The specific method is as follows: (1) Dry the red mud, grind it, and calcine it at 400℃ for 30 minutes before use; (2) Spread the red mud obtained in step (1) on the quartz wool of the suspension device, and place the oil-based wet paint residue in the quartz crucible of the suspension device. The amount of oil-based wet paint residue is 50% of the amount of red mud. The suspension device is fixed in the reactor by the suspension ring to carry out the reaction. When the reaction occurs, under the heat preservation effect of the heat preservation and plugging pipe, the paint residue in the quartz crucible is pyrolyzed. The pyrolysis atmosphere moves upward and comes into contact with the red mud on the quartz wool and reacts. The reactor heating rate is 10℃ / min. After the closed heating is raised to the reaction temperature of 1000℃, the gas outlet valve is opened and the reaction is carried out for 60min. The gas outlet of the reactor is connected to the gas washing, drying and dust removal device to collect the synthesis gas H2 and CO. After the heat preservation ends and the reactor is cooled down, the reduced red mud is obtained. (3) Magnetic separation is performed on the reduced red mud to extract iron from the red mud; The suspension device includes a quartz crucible (1), quartz wool (2), heat-insulating plug (3), suspension ring (4), high-temperature resistant tungsten wire (5), fixing ring I (6), and fixing ring II (7); Quartz crucible (1), quartz wool (2), heat insulation plug (3), suspension ring (4), fixing ring I (6), and fixing ring II (7) are connected by high-temperature tungsten wire (5). Quartz crucible (1) is connected at the bottom of the high-temperature tungsten wire (5). Fixing ring II (7) is connected to the upper part of quartz crucible (1). Suspension ring (4) is installed at the top of the high-temperature tungsten wire (5). Heat insulation plug (3) is connected below the suspension ring (4). Fixing ring I (6) is connected below the heat insulation plug (3). Quartz wool (2) is connected between the heat insulation plug (3) and quartz crucible (1).

2. The method for resource utilization of red mud and paint residue according to claim 1, characterized in that: The paint residue is either oil-based dry paint residue or oil-based wet paint residue.

3. The method for resource utilization of red mud and paint residue according to claim 1, characterized in that: The red mud mentioned is Bayer process red mud.

4. The method for resource utilization of red mud and paint residue according to claim 1, characterized in that: In step (2), the reactor is a vertical tube furnace.

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