CN112237987B - Method for improving recovery rate of magnetic metal in household garbage incinerator slag - Google Patents
Method for improving recovery rate of magnetic metal in household garbage incinerator slag Download PDFInfo
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- CN112237987B CN112237987B CN202010727390.8A CN202010727390A CN112237987B CN 112237987 B CN112237987 B CN 112237987B CN 202010727390 A CN202010727390 A CN 202010727390A CN 112237987 B CN112237987 B CN 112237987B
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- slag
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- magnetic metal
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C1/00—Magnetic separation
- B03C1/005—Pretreatment specially adapted for magnetic separation
- B03C1/01—Pretreatment specially adapted for magnetic separation by addition of magnetic adjuvants
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C21/00—Disintegrating plant with or without drying of the material
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C1/00—Magnetic separation
- B03C1/02—Magnetic separation acting directly on the substance being separated
- B03C1/10—Magnetic separation acting directly on the substance being separated with cylindrical material carriers
Abstract
The invention relates to a method for improving the recovery rate of magnetic metal in household garbage incinerator slag, which comprises the following steps: s1, enabling garbage incinerator slag to sequentially enter a crusher (1), a primary magnetic separation device (2) and a sand making machine (3), separating ferromagnetic substances from slag, and controlling the discharge grain size to be 5-10 mm: s2, placing the slag processed in the step S1 into a stirrer (4), adding an oxygen-free aqueous solution of ferric chloride and ferrous sulfate with the total mass of the slag of 0.8-2.5% and the molar ratio of 3:2, adding a dispersing agent with the mass fraction of 3-10% of the final aqueous solution, introducing nitrogen, opening the heater (5) to enable the temperature of the stirrer to be 85-100 ℃, and stirring for 60-120 min at the temperature; s3, enabling the slag-water mixture processed in the step S2 to enter a secondary magnetic separation device (6) to separate magnetic substances from non-magnetic substances, then placing the magnetic metal collected by the primary magnetic separation device and the secondary magnetic separation device into a dryer (7), and drying the magnetic metal at the temperature of 100-120 ℃ for 1-3 hours to recover the magnetic metal. The method provided by the invention can improve the recovery rate of the magnetic metal in the waste incineration slag, can also improve the alkalinity in the slag waste water, and reduces the treatment difficulty of the subsequent waste water.
Description
Technical Field
The invention belongs to the field of solid waste pollution control, and relates to a method for improving the recovery rate of magnetic metal in household garbage incinerator slag.
Background
Since 2003, the incineration treatment ratio of municipal solid waste in China rises year by year, from 4.6% in 2003 to 40.2% in 2017, and the ratio of incineration power generation in municipal solid waste treatment in 2020 is more than 50%. However, a slag, which is a by-product, is inevitably generated after the incineration of the garbage, and according to reports, about 20% of slag is generated per ton of the incineration of the household garbage. The greatly increased garbage incinerator slag has generated a certain constraint effect on the economic and green development of China, and the effective treatment strategy of the garbage incinerator slag is urgently needed to be researched.
The garbage incinerator slag is greatly different from common slag (mainly slag generated in a metallurgical process), mainly comprises CaO, siO2, al2O3 and Fe2O3, is natural alkaline, has engineering properties similar to natural aggregates, and has wide resource utilization prospect. However, the slag is separated before recycling, and mainly magnetic metal (iron), non-magnetic metal (copper, zinc) and non-metal (glass, ceramic and tailings) are separated, but after the slag is burnt at high temperature (above 800 ℃), the magnetic metal, the non-magnetic metal, the slag and the organic matters which are not completely burnt are adhered together, so that the subsequent separation is difficult. For convenience in subsequent treatment, the slag is usually crushed firstly, but the magnetic force of the magnetic metal is reduced along with the reduction of the particle size, so that the recovery of the magnetic metal is weakened, the recycling of tailings (glass, ceramics and slag) is difficult, for example, iron and nickel react with water at normal temperature and normal pressure to generate hydrogen, and bricks or building materials made of the tailings are cracked. Therefore, the existing technology needs to be improved, and the recovery rate of the magnetic metal in the garbage incinerator slag is improved.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a method for improving the recovery rate of magnetic metal in household garbage incinerator slag.
In order to achieve the above object, the present invention uses the following method:
(S1) enabling the garbage incineration slag to sequentially enter a crusher (1), a primary magnetic separation device (2) and a sand making machine (3), separating ferromagnetic substances from the slag, and controlling the discharge grain size to be 5-10 mm.
Wherein the crusher (1) is a crusher which can select slag particles with the diameter smaller than 100mm to enter the next working procedure, and stone blocks, concrete blocks and large-sized metal blocks are selected or sent to a sanding machine.
The primary magnetic separation device (2) is a suspension type magnetic iron remover, and mainly aims to perform primary separation on ferromagnetic metals in garbage incinerator slag.
The sand blasting machine (3) breaks up hard substances such as slag blocks, stone blocks, mixed clay blocks and the like with the diameters of less than 100mm in slag, and can break up the particle size into particles with the size of 5-10 mm.
(S2) placing the slag treated in the step (S1) into a stirrer (4), adding an oxygen-free aqueous solution of ferric chloride and ferrous sulfate with the molar ratio of 3:2 and 0.8-2.5% of the total mass of the slag, adding a dispersing agent with the mass fraction of 3-10% of the final aqueous solution, introducing nitrogen, and opening a heater (5) to enable the temperature of the stirrer to be 85-100 ℃ and stirring for 60-120 min at the temperature.
The function of the dispersing agent is to keep the magnetic metal particles in the slag and other particles in a dispersed state, and the dispersing agent comprises one or more of DC dispersing agent (commercial), polyethylene glycol and sodium hexametaphosphate;
and (S3) enabling the slag-water mixture processed in the step (S2) to enter a secondary magnetic separation device (6) to separate magnetic substances from non-magnetic substances, then putting the magnetic metal collected by the primary magnetic separation device and the secondary magnetic separation device into a dryer (7), and drying at the temperature of 100-120 ℃ for 1-3 hours to recover the magnetic metal.
The secondary magnetic separation device (6) is a drum-type magnetic iron remover, and the main purpose of the secondary magnetic separation device is to further separate small-particle weak magnetic metals in the crushed slag.
After the slag is dissolved in water, the pH value is alkaline, so that the slag reacts with the added FeCl3 and FeSO4 to produce magnetic Fe3O4, and magnetic fluid is formed in the dispersing agent. The principle of the invention is that the Fe3O4 in the formed magnetic fluid can be selectively adsorbed on the magnetic metal particles in the slag, so that the magnetic metal particles are gathered and agglomerated, and the magnetism is enhanced, thus the magnetic separation from non-magnetic substances can be easier and more convenient in the subsequent magnetic separation.
The invention has the beneficial effects that:
1. harmless, cheap and easily available FeCl3 and FeSO4 are added into the garbage incinerator slag to form Fe3O4, and the Fe3O4 is selectively adsorbed on magnetic metal in the slag, so that the magnetism of magnetic metal particles in the slag is enhanced, and the separation efficiency of the magnetic metal particles is greatly improved.
2. The whole process does not need to add alkali, and can neutralize a part of alkalinity in slag, thereby avoiding the generation of high-alkali wastewater in the traditional treatment method and reducing the subsequent treatment difficulty.
Drawings
FIG. 1 is a schematic view of the process used in the present invention.
In the figure: 1-a crusher; 2-a primary magnetic separation device; 3-sanding machine; 4-a stirrer; 5-a heater; 6-a secondary magnetic separation device; 7-dryer.
Detailed Description
The present invention is further illustrated below with reference to specific examples and figures, but the examples are not intended to limit the invention in any way. Unless specifically stated otherwise, the reagents, methods and apparatus employed in the present invention are those conventional in the art.
In the invention, a method for improving the recovery rate of magnetic metal in household garbage incinerator slag comprises the following steps: (S1) enabling garbage incinerator slag to sequentially enter a crusher (1), a primary magnetic separation device (2) and a sand making machine (3), separating ferromagnetic substances from slag, and controlling the particle size of a discharge material to be 5-10 mm; s2, placing the slag processed in the step S1 into a stirrer (4), adding an oxygen-free aqueous solution of ferric chloride and ferrous sulfate with the total mass of the slag of 0.8-2.5% and the molar ratio of 3:2, adding a dispersing agent with the mass fraction of 3-10% of the final aqueous solution, introducing nitrogen, and opening the heater (5) to enable the temperature of the stirrer to be 85-100 ℃ and stirring for 60-120 min at the temperature; s3, enabling the slag-water mixture processed in the step S2 to enter a secondary magnetic separation device (6) to separate magnetic substances from non-magnetic substances, then placing the magnetic metal collected by the primary magnetic separation device and the secondary magnetic separation device into a dryer (7), and drying the magnetic metal at the temperature of 100-120 ℃ for 1-3 hours to recover the magnetic metal.
In the invention, the crusher (1) is a type that can pick out slag particles with a diameter of less than 100mm to enter the next process, while stone blocks, concrete blocks and large metal blocks with larger volumes are selected out or sent to a sanding machine.
In the invention, the primary magnetic separation device (2) is a suspension type magnetic iron remover, and the primary purpose of the primary separation device is to primarily separate ferromagnetic metals in garbage incinerator slag.
In the invention, the sand blasting machine (3) breaks up hard substances such as slag blocks, stone blocks, concrete blocks and the like with diameters of less than 100mm in slag, and can break up the particles with the particle diameters of 5-10 mm.
In the invention, (S2) the slag treated in the step (S1) is placed into a stirrer (4), an oxygen-free aqueous solution of ferric chloride and ferrous sulfate with the molar ratio of 3:2 and 0.8-2.5% of the total mass of the slag are added, a dispersing agent with the mass fraction of 3-10% of the final aqueous solution is added, nitrogen gas is introduced, a heater (5) is turned on to ensure that the temperature of the stirrer is 85-100 ℃, and the stirrer is stirred for 60-120 min at the temperature.
In the present invention, the dispersant includes one or more of DC dispersant (commercially available), polyethylene glycol, sodium hexametaphosphate.
In the invention, (S3) the slag-water mixture processed by (S2) enters a secondary magnetic separation device (6) to separate magnetic substances from non-magnetic substances, then the magnetic metal collected by the primary magnetic separation device and the secondary magnetic separation device is put into a dryer (7) and dried for 1-3 hours at the temperature of 100-120 ℃, thus the magnetic metal can be recovered.
In the invention, the secondary magnetic separation device (6) is a drum-type magnetic iron remover, and the main purpose of the secondary magnetic separation device is to further separate small-particle weak magnetic metals in the crushed slag.
Example 1
The steps for improving the recovery rate of the magnetic metal in the garbage incinerator slag are as follows:
s1, enabling garbage incinerator slag to sequentially enter a crusher (1), a primary magnetic separation device (2) and a sand making machine (3), separating ferromagnetic substances from slag, and controlling the discharge particle size to be 5-10 mm; s2, placing the slag processed in the step S1 into a stirrer (4), adding an oxygen-free aqueous solution of ferric chloride and ferrous sulfate with the mass ratio of 1.5% of the total mass of the slag being 3:2, adding a 5% DC-40 dispersing agent with the mass fraction of the final aqueous solution, introducing nitrogen, opening the heater (5) to enable the temperature of the stirrer to be 90 ℃, and stirring for 120min at the temperature; s3, placing the slag-water mixture into a secondary magnetic separation device (6) to separate magnetic substances from non-magnetic substances, and finally placing the magnetic metal collected by the primary magnetic separation device and the secondary magnetic separation device into a dryer (7), and drying at a certain temperature for a certain time to recover the magnetic metal, wherein the collection efficiency is more than 98.6%.
Comparative example 1
The difference from example 1 is that the recovery of magnetic metal in the conventional process is simulated, i.e. no ferric chloride, ferrous sulfate and dispersant are added, pure water is used instead, and other experimental conditions are the same, and the collection rate of nonferrous metal is only about 64.8%.
The results of example 1 and comparative example 1 show that the method provided by the invention significantly improves the recovery rate of magnetic metals in the waste incineration slag.
While the foregoing is directed to embodiments of the present invention, other and further details of the invention may be embodied and described herein, it will be appreciated that the foregoing description is merely illustrative of the present invention and, accordingly, the invention is not to be limited to the specific embodiments of the present invention, but is to be accorded the full scope of the present invention.
Claims (6)
1. A method for improving the recovery rate of magnetic metal in household garbage incinerator slag, which comprises the following steps:
(S1) enabling garbage incinerator slag to sequentially enter a crusher (1), a primary magnetic separation device (2) and a sand making machine (3), separating ferromagnetic substances from slag, and controlling the discharge particle size to be 5-10 mm;
(S2) putting the slag treated in the step (S1) into a stirrer (4), adding an oxygen-free aqueous solution of ferric chloride and ferrous sulfate with the total mass of the slag of 0.8-2.5% and the molar ratio of 3:2, adding a dispersing agent with the mass fraction of 3-10% of the final aqueous solution, introducing nitrogen, and opening the heater (5) to enable the temperature of the stirrer to be 85-100 ℃ and stirring for 60-120 min at the temperature;
and (S3) enabling the slag-water mixture processed in the step (S2) to enter a secondary magnetic separation device (6) to separate magnetic substances from non-magnetic substances, then putting the magnetic metal collected by the primary magnetic separation device and the secondary magnetic separation device into a dryer (7), and drying the magnetic metal at the temperature of 100-120 ℃ for 1-3 hours to recover the magnetic metal.
2. A method according to claim 1, wherein the crusher (1) picks up slag particles smaller than 100mm in diameter for the next process, and larger-sized stones, concrete blocks and large-sized metal are picked up or sent to a sanding machine.
3. The method according to claim 1, wherein the primary magnetic separation device (2) is a suspended magnetic iron remover for primarily separating ferromagnetic metals in the waste incineration slag.
4. The method according to claim 1, wherein the sand mill (3) breaks up hard substances such as slag blocks, stone blocks and concrete blocks having a diameter of 100mm or less in the slag, and pulverizes the particles into particles having a particle size of 5 to 10 mm.
5. The method of claim 1, wherein the dispersant comprises one or more of a DC dispersant, polyethylene glycol, sodium hexametaphosphate.
6. The method according to claim 1, wherein the secondary magnetic separation device (6) is a drum-type magnetic iron remover, and small-particle weakly magnetic metals in the crushed slag are further separated.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010727390.8A CN112237987B (en) | 2020-07-24 | 2020-07-24 | Method for improving recovery rate of magnetic metal in household garbage incinerator slag |
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| CN202010727390.8A CN112237987B (en) | 2020-07-24 | 2020-07-24 | Method for improving recovery rate of magnetic metal in household garbage incinerator slag |
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| CN112237987A CN112237987A (en) | 2021-01-19 |
| CN112237987B true CN112237987B (en) | 2023-09-15 |
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| CN112871742A (en) * | 2021-01-29 | 2021-06-01 | 广东中翔环保建材有限公司 | Household garbage incinerator slag crushing, sorting and recycling process |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005329400A (en) * | 2004-04-22 | 2005-12-02 | Daido Steel Co Ltd | Method for stabilizing slag solidification product |
| CN101016588A (en) * | 2007-03-08 | 2007-08-15 | 北京化工大学 | Method of eliminating and reclaiming metal form petroleum |
| CN103406329A (en) * | 2013-07-05 | 2013-11-27 | 广东环兴环保节能科技有限公司 | Method for comprehensively treating and utilizing household garbage incineration slag |
| CN110420970A (en) * | 2019-08-02 | 2019-11-08 | 宇创环保产业有限公司 | A kind of domestic garbage burning electricity generation clinker wet process resource utilization system |
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2020
- 2020-07-24 CN CN202010727390.8A patent/CN112237987B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005329400A (en) * | 2004-04-22 | 2005-12-02 | Daido Steel Co Ltd | Method for stabilizing slag solidification product |
| CN101016588A (en) * | 2007-03-08 | 2007-08-15 | 北京化工大学 | Method of eliminating and reclaiming metal form petroleum |
| CN103406329A (en) * | 2013-07-05 | 2013-11-27 | 广东环兴环保节能科技有限公司 | Method for comprehensively treating and utilizing household garbage incineration slag |
| CN110420970A (en) * | 2019-08-02 | 2019-11-08 | 宇创环保产业有限公司 | A kind of domestic garbage burning electricity generation clinker wet process resource utilization system |
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