A cold rolling mill finishing liquid recovery device

Abstract

The present application relates to cold-rolled rolling liquid processing technical field, specifically disclose a kind of cold-rolled finishing liquid recovery device, including sequentially communicating high field strength magnetic separation device, cyclone air floatation device and circulating liquid storage tank along the flow direction of finishing waste liquid;High field strength magnetic separation device is used to adsorb magnetic metal powder in waste liquid;Cyclone air floatation device includes cyclone cylinder, dissolved air pump and micro-bubble generator, for removing suspended solids and oil substances;Circulating liquid storage tank stores finishing liquid after purification, and its liquid outlet is connected to finishing machine liquid supply pipeline;The present application adopts two-stage classification treatment of "magnetic separation and cyclone air floatation", first remove magnetic particles to protect subsequent equipment, then through micro-bubble adhesion and scraping non-magnetic contaminants, effectively avoid the problem that single magnetic filter is easy to block and backwash frequently, while significantly reducing the overall replacement frequency and operating cost of finishing liquid, simple structure, stable operation, suitable for cold-rolled finishing liquid on-line recycling and recycling.

Description

Technical Field

[0001] This invention relates to the field of cold rolling mill finishing solution treatment technology, and specifically discloses a cold rolling mill finishing solution recovery device. Background Technology

[0002] In the cold rolling finishing process, the finishing solution (also known as the leveling solution) will continuously accumulate magnetic iron powder, zinc powder, and non-magnetic suspended matter (such as wear particles) and oily substances (such as rolling oil, hydraulic oil, and lubricating oil) from the rolling process due to long-term recycling. These contaminants will reduce the lubrication and cleaning performance of the finishing solution and directly affect the surface quality of the strip.

[0003] Currently, the common method for treating finishing solutions in the industry is to use magnetic filters, which utilize electromagnets to attract magnetic metal powders from the waste liquid. The filtered liquid is then returned to a circulation tank for reuse. However, this existing technology has the following two significant drawbacks:

[0004] Magnetic filters are primarily designed for magnetic particles, but they have virtually no ability to remove the large amounts of non-magnetic suspended matter and emulsified oils present in finishing solutions. These substances gradually adhere to and clog the filter media or backwash channels, causing the filter differential pressure to rise rapidly. This necessitates frequent high-pressure backwashing and may even force the machine to shut down for cleaning, severely impacting the continuous operating efficiency of the finishing process.

[0005] When pollutants accumulate to a certain level, magnetic filtration alone is no longer sufficient to restore the quality of the finishing solution. In such cases, the entire tank of finishing solution must be discarded and re-prepared. This not only results in a significant waste of the finishing solution itself but also in the additional consumption of demineralized water, while simultaneously increasing the environmental burden of wastewater treatment.

[0006] Therefore, there is an urgent need for a recycling device that can remove magnetic and non-magnetic contaminants from finishing solutions in stages and enable the long-term stable reuse of finishing solutions. Summary of the Invention

[0007] This invention proposes a cold rolling mill finishing liquid recycling device, which effectively solves the problems of easy clogging and high replacement cost of finishing liquid in existing devices through the synergistic classification and purification of magnetic separation and cyclone flotation, and realizes the long-term stable recycling of finishing liquid.

[0008] The present invention is implemented as follows: a cold rolling mill finishing liquid recovery device, comprising: a high field strength magnetic separation device, a cyclone air flotation device and a circulating storage tank connected in sequence along the flow direction of the finishing waste liquid;

[0009] The high field strength magnetic separation device is used to adsorb magnetic metal powder in the finishing waste liquid;

[0010] The cyclone flotation device is used to remove suspended solids and oily substances from the finishing liquid after magnetic separation. The cyclone flotation device includes a cyclone cylinder, a dissolved air pump, and a microbubble generator. The upper part of the cyclone cylinder is provided with a tangential liquid inlet, the top is provided with a slag scraping mechanism, and the bottom is provided with a liquid outlet. The outlet of the high-field magnetic separation device is connected to the tangential liquid inlet of the cyclone cylinder. The inlet of the dissolved air pump is connected to the circulating liquid storage tank, and the outlet of the dissolved air pump is connected to the microbubble generator. The microbubble generator is located at the bottom of the cyclone cylinder and is used to generate microbubbles. The liquid outlet of the cyclone cylinder is connected to the liquid inlet of the circulating liquid storage tank.

[0011] As a preferred embodiment of the cold rolling mill finishing liquid recovery device of the present invention, the magnetic field strength of the high field strength magnetic separation device is 2000-4000 Gauss.

[0012] As a preferred embodiment of the cold rolling mill finishing liquid recovery device of the present invention, the slag scraping mechanism is a spiral slag discharge machine, which is fixed to the top of the vortex cylinder and its spiral blades extend into the liquid surface slag layer inside the vortex cylinder.

[0013] As a preferred embodiment of the cold rolling mill finishing liquid recovery device of the present invention, the bottom of the cyclone cylinder is conical and is provided with a slag discharge pipe, and the slag discharge pipe is provided with a slag discharge valve.

[0014] As a preferred embodiment of the cold rolling mill finishing liquid recovery device of the present invention, the microbubble generator is used to generate microbubbles with a diameter of less than 50 micrometers.

[0015] As a preferred embodiment of the cold rolling mill finishing liquid recycling device of the present invention, the outlet of the circulating liquid storage tank is connected to the finishing mill supply pipeline, which is used to transport the purified finishing liquid to the cold rolling finishing mill for recycling.

[0016] The beneficial effects of this invention are:

[0017] 1. By connecting a high-field-strength magnetic separation device and a cyclone air flotation device in series to form a two-stage synergistic graded treatment system of 'magnetic separation-cyclone air flotation', the magnetic separation device first removes abrasive magnetic hard particles to protect the subsequent air flotation equipment and prevent it from clogging. Then, the cyclone air flotation device efficiently removes non-magnetic suspended matter and emulsified oil. The two complement each other and work synergistically to fundamentally solve the problems of easy clogging and frequent backwashing of single magnetic filters.

[0018] 2. Because it can efficiently remove magnetic and non-magnetic contaminants, the water quality after treatment with the brightening solution can meet the reuse standards for a long time without the need for frequent overall replacement. This not only reduces the consumption of the brightening solution itself, but also reduces the amount of demineralized water replenishment and waste liquid treatment, thereby saving production and operating costs. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0021] Figure 2 for Figure 1 A schematic diagram of the AA-direction cross-section structure.

[0022] The markings in the diagram are: 1. High field strength magnetic separation device; 2. Cyclone air flotation device; 3. Circulating liquid storage tank; 4. Cyclone cylinder; 5. Dissolved air pump; 6. Microbubble generator; 7. Tangential liquid inlet; 8. Slag scraping mechanism; 9. Liquid outlet; 10. Slag discharge pipe; 11. Slag discharge valve; 12. Liquid supply pipeline for the finishing machine. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments to aid in understanding its content. Unless otherwise specified, the methods used in this invention are conventional methods; the raw materials and apparatus used, unless otherwise specified, are conventional commercially available products.

[0024] Please see Figure 1 and 2 A cold rolling mill finishing liquid recovery device includes: a high field strength magnetic separation device 1, a cyclone air flotation device 2, and a circulating storage tank 3 connected in sequence along the flow direction of the finishing waste liquid.

[0025] High field strength magnetic separation device 1 is used to adsorb magnetic metal powder in finishing waste liquid;

[0026] The cyclone flotation device 2 is used to remove suspended solids and oily substances from the finishing liquid after magnetic separation. The cyclone flotation device 2 includes a cyclone cylinder 4, a dissolved air pump 5, and a microbubble generator 6. The upper part of the cyclone cylinder 4 is provided with a tangential liquid inlet 7, the top is provided with a sludge scraping mechanism 8, and the bottom is provided with a liquid outlet 9. The outlet of the high field strength magnetic separation device 1 is connected to the tangential liquid inlet 7 of the cyclone cylinder 4. The inlet of the dissolved air pump 5 is connected to the circulating liquid storage tank 3, and the outlet of the dissolved air pump 5 is connected to the microbubble generator 6. The microbubble generator 6 is located at the bottom of the inside of the cyclone cylinder 4 and is used to generate microbubbles. The liquid outlet 9 of the cyclone cylinder 4 is connected to the liquid inlet of the circulating liquid storage tank 3.

[0027] In this embodiment: the finishing waste liquid first enters the high-field magnetic separation device 1. This device uses a strong magnetic field to adsorb and trap magnetic metal powders (such as iron powder and zinc powder) in the waste liquid to prevent them from abrading subsequent equipment. After magnetic separation, the waste liquid enters the cyclone cylinder 4 from the tangential inlet 7. The tangential inlet causes the liquid to generate a high-speed rotating cyclone field in the cylinder. Under the action of centrifugal force, heavier particles settle to the cylinder wall and bottom. At the same time, the dissolved air pump 5 draws the purified finishing liquid from the circulating storage tank 3, pressurizes it and sends it to the microbubble generator 6. The microbubble generator 6 generates a large number of microbubbles with a diameter of less than 50 micrometers at the bottom of the cyclone cylinder 4. During the rising process, these bubbles collide and adhere with suspended matter and oil in the waste liquid to form scum with a density less than water. The scum floats to the surface of the liquid and is scraped off by the top scraper mechanism 8. The finishing liquid purified by magnetic separation, cyclone settling and air flotation flows into the circulating storage tank 3 from the bottom outlet 9, completing the first stage of purification.

[0028] As a technical optimization of the present invention, the magnetic field strength of the high field strength magnetic separation device is 2000-4000 Gauss.

[0029] In this embodiment, a magnetic field strength of 2000-4000 Gauss ensures sufficient adsorption capacity for magnetic iron powder and zinc powder, while avoiding excessively high magnetic fields that could lead to higher equipment costs and unnecessary energy consumption.

[0030] As a technical optimization of the present invention, the slag scraping mechanism 8 is a spiral slag discharge machine, which is fixed to the top of the vortex cylinder 4, and its spiral blades extend into the liquid surface slag layer inside the vortex cylinder 4.

[0031] In this embodiment, the spiral blades extend into the scum layer to achieve continuous and automatic scraping of the scum, avoiding manual cleaning and improving the automation and stability of the device operation.

[0032] As a technical optimization of the present invention, the bottom of the cyclone cylinder 4 is conical and is provided with a slag discharge pipe 10, and a slag discharge valve 11 is provided on the slag discharge pipe 10.

[0033] In this embodiment, the sludge discharge pipe 10 and the sludge discharge valve 11 facilitate the collection of heavier sludge (such as a small amount of unadsorbed heavy particles) at the bottom of the cone and their periodic discharge, preventing sludge accumulation from affecting the quality of the effluent.

[0034] As a technical optimization of the present invention, the microbubble generator 6 is used to generate microbubbles with a diameter of less than 50 micrometers.

[0035] In this embodiment, 50-micron microbubbles ensure that the bubble size is small enough to achieve high adhesion efficiency with suspended solids and oil droplets, thereby improving the air flotation separation effect.

[0036] As a technical optimization of the present invention, the outlet of the circulating liquid storage tank 3 is connected to the liquid supply pipeline 12 of the finishing machine, which is used to transport the purified finishing liquid to the cold rolling finishing machine for recycling.

[0037] In this embodiment, the finishing machine supply pipeline 12 directly transports the purified finishing liquid back to the cold rolling finishing machine for recycling, forming a closed-loop system to achieve resource conservation and zero emissions.

[0038] Working principle and usage process of this invention:

[0039] The finishing waste liquid first enters the high-field magnetic separation device 1 (magnetic field strength 2000-4000 Gauss), where the device adsorbs magnetic iron powder, zinc powder and other metal particles in the waste liquid, resulting in preliminarily purified waste liquid. The preliminarily purified waste liquid enters the cyclone cylinder 4 tangentially, generating a cyclone centrifugal effect that causes a small amount of heavy sludge to settle to the bottom of the cone. At the same time, the dissolved air pump 5 draws the purified finishing liquid from the circulating storage tank 3, and after pressurization, a large number of microbubbles (diameter <50μm) are released at the bottom of the cylinder by the microbubble generator 6. During the rising process, the bubbles adhere to non-magnetic suspended matter and oily substances in the waste liquid, forming scum that floats to the surface. The spiral scum remover at the top continuously scrapes out the scum. The sediment at the bottom of the cone is periodically discharged through the scum discharge valve 11. The purified finishing liquid flows into the circulating storage tank 3 from the liquid outlet 9 at the bottom of the cyclone cylinder 4. Part of the purified finishing liquid in the circulating storage tank 3 is returned to the microbubble generator 6 through the dissolved air pump 5 (to maintain the air flotation circulation), and the other part is transported to the cold rolling finishing machine through the liquid supply pipeline to realize the recycling of the finishing liquid.

Claims

1. A cold rolling mill finishing liquid recovery device, characterized in that, include: A high-field magnetic separation device (1), a cyclone flotation device (2), and a circulating storage tank (3) are connected sequentially along the flow direction of the polishing waste liquid. The high field strength magnetic separation device (1) is used to adsorb magnetic metal powder in the finishing waste liquid. The cyclone flotation device (2) is used to remove suspended solids and oily substances from the finishing liquid after magnetic separation. The cyclone flotation device (2) includes a cyclone cylinder (4), a dissolved air pump (5), and a microbubble generator (6). The upper part of the cyclone cylinder (4) is provided with a tangential liquid inlet (7), the top is provided with a slag scraping mechanism (8), and the bottom is provided with a liquid outlet (9). The outlet of the high field strength magnetic separation device (1) is connected to the tangential liquid inlet (7) of the cyclone cylinder (4). The inlet of the dissolved air pump (5) is connected to the circulating liquid storage tank (3), and the outlet of the dissolved air pump (5) is connected to the microbubble generator (6). The microbubble generator (6) is located at the bottom of the cyclone cylinder (4) and is used to generate microbubbles. The liquid outlet (9) of the cyclone cylinder (4) is connected to the inlet of the circulating liquid storage tank (3).

2. The cold rolling mill finishing liquid recovery device according to claim 1, characterized in that: The magnetic field strength of the high field strength magnetic separation device (1) is 2000-4000 Gauss.

3. The cold rolling mill finishing liquid recovery device according to claim 1, characterized in that: The slag scraping mechanism (8) is a spiral slag discharge machine, which is fixed to the top of the vortex cylinder (4), and its spiral blades extend into the liquid surface slag layer inside the vortex cylinder (4).

4. The cold rolling mill finishing liquid recovery device according to claim 1, characterized in that: The bottom of the swirl cylinder (4) is conical and is provided with a slag discharge pipe (10), and a slag discharge valve (11) is provided on the slag discharge pipe (10).

5. A cold rolling mill finishing liquid recovery device according to claim 1, characterized in that: The microbubble generator (6) is used to generate microbubbles with a diameter of less than 50 micrometers.

6. The cold rolling mill finishing liquid recovery device according to claim 1, characterized in that: The outlet of the circulating liquid storage tank (3) is connected to the liquid supply pipeline (12) of the finishing machine, which is used to transport the purified finishing liquid to the cold rolling finishing machine for recycling.

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