阅读说明：本技术 磁分离装置、在线反冲洗方法和磁分离的方法 (Magnetic separation device, online backwashing method and magnetic separation method ) 是由 杨如意 孟祥堃 陈强 胡云剑 门卓武 卜亿峰 杜冰 于 2019-10-15 设计创作，主要内容包括：本发明涉及磁分离冲洗领域,公开了磁分离装置、在线反冲洗方法和磁分离的方法。磁分离装置包括：高梯度磁分离器、分开设置在所述高梯度磁分离器的上游和下游的进料单元和冲洗单元,以及控制单元；进料单元包括原料罐、浓液罐和进气源,且原料罐、浓液罐、进气源分别通过带有阀门的管线与所述高梯度磁分离器的入口连通；冲洗单元包括产品罐、冲洗液源、放空管,且产品罐、冲洗液源、放空管通过带有阀门的管线与所述高梯度磁分离器的出口连通；控制单元电连接所述阀门和高梯度磁分离器,控制实现磁分离装置进行吸附和冲洗过程；其中高梯度磁分离器包括分离腔、隔热层、超声发生器、励磁线圈和磁极。解决高温浆料的磁分离问题。(The invention relates to the field of magnetic separation and washing, and discloses a magnetic separation device, an online backwashing method and a magnetic separation method. The magnetic separation device includes: the device comprises a high-gradient magnetic separator, a feeding unit and a flushing unit which are separately arranged at the upstream and the downstream of the high-gradient magnetic separator, and a control unit; the feeding unit comprises a raw material tank, a concentrated solution tank and an air inlet source, and the raw material tank, the concentrated solution tank and the air inlet source are respectively communicated with the inlet of the high-gradient magnetic separator through pipelines with valves; the flushing unit comprises a product tank, a flushing liquid source and an emptying pipe, and the product tank, the flushing liquid source and the emptying pipe are communicated with an outlet of the high-gradient magnetic separator through a pipeline with a valve; the control unit is electrically connected with the valve and the high gradient magnetic separator and controls the magnetic separation device to perform adsorption and washing processes; wherein the high gradient magnetic separator comprises a separation cavity, a heat insulation layer, an ultrasonic generator, an excitation coil and a magnetic pole. The problem of magnetic separation of high-temperature slurry is solved.)

1. A magnetic separation device, comprising:

the device comprises a high-gradient magnetic separator, a feeding unit and a flushing unit which are separately arranged at the upstream and the downstream of the high-gradient magnetic separator, and a control unit; wherein the content of the first and second substances,

the feeding unit comprises a raw material tank, a concentrated solution tank and an air inlet source, and the raw material tank, the concentrated solution tank and the air inlet source are respectively communicated with the inlet of the high-gradient magnetic separator through pipelines with valves;

the flushing unit comprises a product tank, a flushing liquid source and an emptying pipe, and the product tank, the flushing liquid source and the emptying pipe are communicated with an outlet of the high-gradient magnetic separator through a pipeline with a valve;

the control unit is electrically connected with the valve and the high gradient magnetic separator and controls the magnetic separation device to perform adsorption and flushing processes;

the high-gradient magnetic separator comprises a separation cavity, a heat insulation layer, an ultrasonic generator, an excitation coil and a magnetic pole.

2. The device of claim 1, wherein the separation chamber is filled with a magnetic medium, a heat insulation layer is arranged outside the separation chamber, the ultrasonic generator is arranged outside the heat insulation layer, and the excitation coil is arranged outside the ultrasonic generator;

the magnetic poles are arranged at the inlet end and the outlet end of the separation cavity and comprise an inner magnetic pole and an outer magnetic pole.

3. The device according to claim 1 or 2, wherein in the feeding unit, the inlet of the high gradient magnetic separator is communicated with a raw material tank, a concentrated solution tank and an air inlet source through pipelines with a feeding valve, a flushing discharge valve and an air inlet valve respectively.

4. The apparatus according to any one of claims 1 to 3, wherein in the flushing unit, the outlet of the high gradient magnetic separator is communicated with the product tank, the flushing liquid source and the blow-down pipe through pipelines with a discharge valve, a flushing feed valve and a blow-down valve respectively.

5. A method of on-line backwash of the apparatus of any one of claims 1 to 4 comprising:

(1) stopping introducing the slurry containing the magnetic particles into the high-gradient magnetic separator and closing the magnetic field of the high-gradient magnetic separator;

(2) and starting an ultrasonic generator of the high-gradient magnetic separator to generate ultrasonic waves, introducing flushing liquid and/or gas into the high-gradient magnetic separator, and performing backwashing in the presence of the ultrasonic waves to remove magnetic particles adsorbed on a magnetism gathering medium contained in the high-gradient magnetic separator.

6. A process according to claim 5, wherein the slurry has a solids content of from 0.005 to 15% by weight, a temperature of from 80 to 600 ℃ and a pressure of from 0 to 50 MPa.

7. The method of claim 5, wherein in step (2), the backwashing process comprises one of the following:

the first method is as follows: under the action of ultrasound, opening a flushing feed valve and a flushing discharge valve, flushing the high-gradient magnetic separator by using flushing liquid, and feeding the generated concentrated liquid into a concentrated liquid tank;

the second method comprises the following steps: under the action of ultrasonic wave, opening the air inlet valve and the air release valve, and flushing the high gradient magnetic separator with gas;

the third method comprises the following steps: under the action of ultrasound, opening a flushing feed valve, a flushing discharge valve, an air inlet valve and an air release valve, carrying out gas-liquid mixed flushing on the high-gradient magnetic separator by using flushing liquid and gas, enabling generated concentrated liquid to enter a concentrated liquid tank, and simultaneously emptying the flushed gas;

the method is as follows: under the action of ultrasound, firstly opening an air inlet valve and an air release valve, and carrying out gas flushing on the high-gradient magnetic separator by using gas; then closing the air inlet valve and the air release valve, opening the flushing feed valve and the flushing discharge valve, flushing the high gradient magnetic separator with flushing liquid, and introducing the generated concentrated liquid into a concentrated liquid tank.

8. The method according to any one of claims 5-7, wherein the ultrasound frequency is 1.5 x 10⁴Hz to 1X 10⁷Hz, preferably 1.5X 10⁴Hz to 2X 10⁵Hz; the ultrasonic power is 500W-5000W, preferably 2000W-3000W.

9. A method of magnetic separation, comprising:

(i) introducing the slurry containing the magnetic particles into the device of any one of claims 1 to 4 for liquid-solid separation, adsorbing and accumulating the separated magnetic particles in a high-gradient magnetic separator included in the device, and collecting the separated clear liquid;

(ii) (ii) subjecting the high gradient magnetic separator having magnetic particles adsorbed and accumulated by step (i) to the method of on-line backwashing according to any one of claims 5 to 9;

(iii) repeating steps (i) and (ii) for successive magnetic separations.

10. The method of claim 9, wherein the conditions for starting step (ii) are: the pressure difference between the inlet and the outlet of the separation cavity of the high-gradient magnetic separator is more than 0.1 MPa.

Technical Field

The invention relates to the field of magnetic separation and washing, in particular to a magnetic separation device, an online backwashing method and a magnetic separation method.

Background

The high-gradient magnetic separation technology is a physical method for separating substances by using the magnetic difference of the substances. The high-gradient magnetic separation technology is firstly used for ore dressing, but with the theoretical and technical progress, the method is widely applied to the fields of chemical engineering, water treatment and the like. However, how to efficiently realize the separation of the magnetic medium and the magnetic particles, namely the back washing efficiency, is still a problem.

CN202538920U discloses a continuous ultrasonic-assisted high-gradient superconducting magnetic separation device, which comprises an ultrasonic-assisted system, a superconducting magnet, a high-gradient medium net, a feed inlet, a flushing water outlet and a suspension system, wherein the inside of the superconducting magnet is provided with the flushing water outlet, and the outside of the superconducting magnet is provided with the feed inlet; the feed inlet is connected with an ultrasonic auxiliary system. The ultrasonic action in the equipment is to eliminate the agglomeration phenomenon of most fine particle materials in the dispersion liquid. Because the back washing process has no ultrasonic auxiliary effect, the back washing is not thorough.

CN108525847A discloses a periodic alternating superconducting magnetic separator, which comprises a superconducting magnetic source and a separation mechanism, wherein the superconducting magnetic source comprises a hollow solenoid main coil, compensation coils are respectively arranged at the parts of the outside of the hollow solenoid main coil, which are close to the two ends, and the hollow solenoid main coil and the compensation coils are wound by superconducting wires; the sorting mechanism comprises a sorting cavity, the sorting cavity is connected with a linear motion driving mechanism, and the sorting cavity enters and exits from the core part of the main coil of the hollow solenoid. The device makes full use of the strong magnetic field generated by the superconducting magnetic source through the periodic in-and-out magnetic field region of the sorting mechanism, and has good separation effect on minerals with low specific susceptibility. However, in the back washing process, the device only uses the discharged water to wash the magnetic particles, the magnetic particles are difficult to wash, the regeneration effect is poor, and the magnetic separation efficiency is influenced.

In the chemical field, the problem of liquid-solid material system separation is often encountered, and the separation is generally carried out by adopting settling, filtering and centrifuging methods at present. When the solid particles are large in size, the method can obtain a good separation effect, and is simple in equipment and low in energy consumption; as the particle size decreases, the complexity and energy consumption of the separation equipment also increases, and the equipment cost increases significantly when exposed to harsh process conditions such as high temperature, high pressure, etc. It is therefore desirable to provide a process that is capable of separating liquid-solid feed systems containing small particle sizes.

Disclosure of Invention

The invention aims to overcome the problem of how to realize stable magnetic separation of high-temperature slurry containing magnetic particles, and provides a magnetic separation device, an online backwashing method and a magnetic separation method. The device and the method can realize gas and/or liquid flushing in the presence of ultrasound, so that the slurry containing magnetic particles with high temperature can obtain stable and continuous magnetic separation effect.

In order to achieve the above object, a first aspect of the present invention provides a magnetic separation device comprising:

the device comprises a high-gradient magnetic separator, a feeding unit and a flushing unit which are separately arranged at the upstream and the downstream of the high-gradient magnetic separator, and a control unit; wherein the content of the first and second substances,

the feeding unit comprises a raw material tank, a concentrated solution tank and an air inlet source, and the raw material tank, the concentrated solution tank and the air inlet source are respectively communicated with the inlet of the high-gradient magnetic separator through pipelines with valves;

the flushing unit comprises a product tank, a flushing liquid source and an emptying pipe, and the product tank, the flushing liquid source and the emptying pipe are communicated with an outlet of the high-gradient magnetic separator through a pipeline with a valve;

the control unit is electrically connected with the valve and the high gradient magnetic separator and controls the magnetic separation device to perform adsorption and flushing processes;

the high-gradient magnetic separator comprises a separation cavity, a heat insulation layer, an ultrasonic generator, an excitation coil and a magnetic pole.

Preferably, the inside of the separation cavity is filled with a magnetic medium, and a heat insulation layer is arranged outside the separation cavity; the ultrasonic generator is arranged outside the heat insulation layer, and the excitation coil is arranged outside the ultrasonic generator; the magnetic poles are arranged at the inlet end and the outlet end of the separation cavity and comprise an inner magnetic pole and an outer magnetic pole.

Preferably, in the feeding unit, the inlet of the high gradient magnetic separator is communicated with the raw material tank, the concentrate tank and the air inlet source through pipelines with a feeding valve, a flushing discharge valve and an air inlet valve respectively.

Preferably, in the flushing unit, the outlet of the high gradient magnetic separator is communicated with the product tank, the flushing liquid source and the vent pipe through pipelines with a discharge valve, a flushing feed valve and a vent valve respectively.

In a second aspect, the present invention provides a method for on-line backwashing of the apparatus of the present invention, comprising:

(1) stopping introducing the slurry containing the magnetic particles into the high-gradient magnetic separator and closing the magnetic field of the high-gradient magnetic separator;

(2) and starting an ultrasonic generator of the high-gradient magnetic separator, introducing flushing liquid and/or gas into the high-gradient magnetic separator, performing backwashing in the presence of ultrasonic waves, and removing magnetic particles adsorbed on a magnetism gathering medium of the high-gradient magnetic separator.

Preferably, the slurry has a solid content of 0.005 to 15 wt%, a temperature of 80 to 600 ℃, and a pressure of 0 to 50 MPa.

Preferably, in step (2), the backwashing process includes one of the following steps:

the first method is as follows: under the action of ultrasound, opening a flushing feed valve and a flushing discharge valve, flushing the high-gradient magnetic separator by using flushing liquid, and feeding the generated concentrated liquid into a concentrated liquid tank;

the second method comprises the following steps: under the action of ultrasonic wave, opening the air inlet valve and the air release valve, and flushing the high gradient magnetic separator with gas;

the third method comprises the following steps: under the action of ultrasound, opening a flushing feed valve, a flushing discharge valve, an air inlet valve and an air release valve, carrying out gas-liquid mixed flushing on the high-gradient magnetic separator by using flushing liquid and gas, enabling generated concentrated liquid to enter a concentrated liquid tank, and simultaneously emptying the flushed gas;

the method is as follows: under the action of ultrasound, firstly opening an air inlet valve and an air release valve, and carrying out gas flushing on the high-gradient magnetic separator by using gas; then closing the air inlet valve and the air release valve, opening the flushing feed valve and the flushing discharge valve, flushing the high gradient magnetic separator with flushing liquid, and introducing the generated concentrated liquid into a concentrated liquid tank.

Preferably, the ultrasonic frequency is 1.5 × 10⁴Hz to 1X 10⁷Hz; the ultrasonic power is 500W-5000W.

A third aspect of the invention provides a method of magnetic separation comprising:

(i) introducing the slurry containing the magnetic particles into the device of the invention for liquid-solid separation, adsorbing and accumulating the separated magnetic particles in a high-gradient magnetic separator included in the device, and collecting the separated clear liquid;

(ii) (ii) performing the on-line backwashing method of the present invention on the high gradient magnetic separator which has been adsorbed and accumulated with the magnetic particles in step (i);

(iii) repeating steps (i) and (ii) for successive magnetic separations.

Preferably, the conditions for starting step (ii) are: the pressure difference between the inlet and the outlet of the separation cavity of the high-gradient magnetic separator is more than 0.1 MPa.

Through the technical scheme, the magnetic separation device provided by the invention is provided with the ultrasonic generator and the corresponding backwashing method, so that the problem of effectively, stably and continuously carrying out magnetic separation on high-temperature slurry containing magnetic particles can be solved. And an ultrasonic generator is adopted, so that the magnetic particles can be quickly separated in the backwashing process, the separation is more thorough, and the backwashing efficiency is improved. The technical scheme provided by the invention can be applied to products obtained by Fischer-Tropsch synthesis by adopting the magnetic catalyst, so that the magnetic catalyst particles are separated, and the Fischer-Tropsch synthesis products with better purity are obtained, so that the Fischer-Tropsch synthesis products can be better processed in a subsequent process.

Drawings

FIG. 1 is a schematic flow diagram of a magnetic separation apparatus provided by the present invention;

FIG. 2 is a schematic diagram of a high gradient magnetic separator.

Description of the reference numerals

1. Lower connecting pipe 2, lower external magnetic pole 3 and ultrasonic generator

4. Excitation coil 5, heat-insulating layer 6, upper outer magnetic pole

7. Upper connecting pipe 8, upper inner magnetic pole 9 and magnetic collecting medium

10. Lower inner magnetic pole

V1, raw material tank H1, high gradient magnetic separator V2 and product tank

V3, concentrated solution tank J1, feed valve J2 and discharge valve

J3, flushing inlet valve J4, flushing outlet valve J5 and inlet valve

J6 atmospheric valve

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

A first aspect of the present invention provides a magnetic separation apparatus, as shown in fig. 1 and 2, comprising:

a high gradient magnetic separator H1, a feeding unit and a flushing unit arranged separately upstream and downstream of the high gradient magnetic separator, and a control unit; wherein the content of the first and second substances,

the feeding unit comprises a raw material tank V1, a concentrated liquid tank V3 and an air inlet source, and the raw material tank V1, the concentrated liquid tank V3 and the air inlet source are respectively communicated with the inlet of the high-gradient magnetic separator through pipelines with valves;

the flushing unit comprises a product tank V2, a flushing liquid source and a vent pipe, and the product tank V2, the flushing liquid source and the vent pipe are communicated with an outlet of the high-gradient magnetic separator through a pipeline with a valve;

the control unit is electrically connected with the valve and the high-gradient magnetic separator H1 and controls the magnetic separation device to perform adsorption and flushing processes;

wherein the high gradient magnetic separator H1 comprises a separation cavity, a heat insulation layer 5, an ultrasonic generator 3, an excitation coil 4 and a magnetic pole.

According to the invention, preferably, the separation cavity is internally filled with a magnetic medium gathering medium 9, and a heat insulation layer 5 is arranged outside the separation cavity; the ultrasonic generator 3 is arranged outside the heat insulation layer 5, and the excitation coil 4 is arranged outside the ultrasonic generator 3; the magnetic poles are arranged at the inlet end and the outlet end of the separation cavity and comprise an inner magnetic pole and an outer magnetic pole. In the magnetic separation device provided by the invention, the heat insulation layer 5 and the ultrasonic generator 3 are arranged, so that the heat influence on the excitation coil 4 can be effectively provided, and the magnetic separation device can be better and more quickly used for completing the desorption of magnetic particles under the ultrasonic condition when the magnetic particles adsorbed on the magnetic gathering medium 9 are washed and removed. As shown in fig. 2, at the inlet end of the separation chamber, the inner magnet is a lower inner magnet pole 10, and the outer magnet is a lower outer magnet pole 2; at the outlet end of the separation chamber, the inner magnetic pole is an upper inner magnetic pole 8 and the outer magnetic pole is an upper outer magnetic pole 6. Preferably, at the inlet end and the outlet end of the separation cavity, the inner magnetic pole and the outer magnetic pole are respectively and correspondingly arranged and are at the same horizontal height, and magnetic leakage is prevented. The inlet end of the separation cavity is communicated with a lower connecting pipe, and the outlet end of the separation cavity is communicated with an upper connecting pipe 7.

According to the invention, preferably, in the feeding unit, the inlet of the high-gradient magnetic separator H1 is communicated with the raw material tank V1, the concentrated solution tank V3 and the air inlet source through pipelines with a feeding valve J1, a flushing discharge valve J4 and an air inlet valve J5 respectively.

According to the invention, preferably, in the flushing unit, the outlet of the high gradient magnetic separator H1 is communicated with the product tank V2, the flushing liquid source and the blow-down pipe through pipelines with a discharge valve J2, a flushing feed valve J3 and a blow-down valve J6 respectively.

In the magnetic separation device provided by the invention, the high-gradient magnetic separator comprises the ultrasonic generator, when the magnetic separation device is used for separating high-temperature slurry containing magnetic particles, the magnetic particle gathering medium contained in the high-gradient magnetic separator can be used for quickly separating the adsorbed magnetic particles under the action of ultrasonic waves emitted by the ultrasonic generator in the desorption step process, so that the regeneration of the magnetic particle gathering medium is effectively realized, and the preparation is prepared for the next adsorption.

In a second aspect, the present invention provides a method for performing on-line backwashing by using the apparatus of the present invention, as shown in fig. 1, including:

(1) stopping the introduction of the slurry containing magnetic particles into the high gradient magnetic separator H1 and turning off the magnetic field of the high gradient magnetic separator;

(2) and starting the ultrasonic generator 3 of the high-gradient magnetic separator H1 to generate super-sonic waves, introducing flushing liquid and/or gas into the high-gradient magnetic separator H1, and performing backwashing in the presence of ultrasonic waves to remove magnetic particles adsorbed on the magnetic gathering medium 9 contained in the high-gradient magnetic separator H1.

In the step (1) provided by the invention, a feed valve J1 between a raw material tank V1 and a high gradient magnetic separator H1 is closed, a discharge valve J2 between a product tank V2 and the high gradient magnetic separator H1 is closed, and the slurry is stopped from being introduced into the high gradient magnetic separator. The magnetic field in the high-gradient magnetic separator is generated by energizing the field coil 4, and by deenergizing, the magnetic field is turned off.

According to the invention, the method can be suitable for magnetic separation of high-temperature slurry. Preferably, the slurry has a solid content of 0.005 to 15 wt%, a temperature of 80 to 600 ℃, and a pressure of 0 to 50 MPa. The prior art can not realize effective slurry magnetic separation under the condition of higher than 80 ℃.

According to the present invention, preferably, in step (2), the backwashing process includes one of the following modes:

the first method is as follows: under the action of ultrasound, a flushing feed valve J1 and a flushing discharge valve J4 are opened, a flushing liquid is used for flushing the high-gradient magnetic separator H1, and the generated concentrated solution enters a concentrated solution tank V3;

the second method comprises the following steps: under the action of ultrasonic wave, opening an air inlet valve J5 and an air release valve J6, and flushing a high-gradient magnetic separator H1 by using gas;

the third method comprises the following steps: under the action of ultrasound, a flushing feed valve J3, a flushing discharge valve J4, an air inlet valve J5 and an emptying valve J6 are opened, flushing liquid and gas are used for carrying out gas-liquid mixed flushing on a high-gradient magnetic separator H1, generated concentrated solution enters a concentrated solution tank V3, and meanwhile, the flushed gas is emptied;

the method is as follows: under the ultrasonic action, firstly opening an air inlet valve J5 and an air release valve J6, and carrying out gas flushing on the high-gradient magnetic separator H1 by using gas; then closing an air inlet valve J5 and an air release valve J6, opening a flushing feed valve J3 and a flushing discharge valve J4, carrying out liquid flushing on the high-gradient magnetic separator H1 by using flushing liquid, and leading generated concentrated liquid to a concentrated liquid tank V3.

According to the invention, preferably, in the fourth mode, the gas flushing and the liquid flushing are alternately performed for 1 to 10 times, and the flushing time is 1 to 5 min.

According to the invention, preferably, the conditions of the ultrasonication comprise: ultrasonic frequency of 1.5 x 10⁴Hz to 1X 10⁷Hz, preferably 1.5X 10⁴Hz to 2X 10⁵Hz; the ultrasonic power is 500W-5000W, preferably 2000W-3000W. The above conditions are provided to facilitate the separation of the magnetic particles adsorbed on the magnetic flux collecting medium 9, thereby providing the efficiency of magnetic separation.

A third aspect of the present invention provides a method of magnetic separation, as shown in fig. 1, comprising:

(i) introducing the slurry containing the magnetic particles into the device of the invention for liquid-solid separation, adsorbing and accumulating the separated magnetic particles in a high-gradient magnetic separator H1 included in the device, and collecting the separated clear liquid;

(ii) (ii) subjecting the high gradient magnetic separator H1 having magnetic particles adsorbed and accumulated in step (i) to the on-line backwashing method of the present invention;

(iii) repeating steps (i) and (ii) for successive magnetic separations.

According to the invention, it is preferred that the conditions for starting step (ii) are: the pressure difference between the inlet and the outlet of the separation cavity of the high-gradient magnetic separator is more than 0.1 MPa. The pressure difference is a pressure difference.

The magnetic separation device, the online backwashing method and the magnetic separation method provided by the invention can be applied to processing products from Fischer-Tropsch synthesis reaction, the products are high-temperature slurry containing magnetic catalyst particles, the effective separation of the magnetic catalyst particles of the products is realized, and the Fischer-Tropsch synthesis products with better purity are provided, so that the subsequent process can better process the Fischer-Tropsch synthesis products. And the application can realize continuous and stable magnetic separation of products from Fischer-Tropsch synthesis reaction.

In the present invention, the pressure is a gauge pressure.

In the present invention, the slurry has a solid content of 100-1000. mu.g/g. Preferably, the slurry temperature is 180 ℃ and 300 ℃, and the slurry pressure is 0.3-1.5 MPa. The slurry viscosity was 2-4cP (180 ℃ C.).

In the present invention, the average particle diameter of the magnetic particles in the slurry is 10 to 75 μm. The saturation magnetization of the particles is 15-20 emu/g.

In the present invention, the cross-sectional flow rate of the slurry into the separation chamber is 0.001 to 0.5m/s, preferably 0.5 m/s.

In the invention, the separation temperature is 180-300 ℃ and the separation pressure is 0.3-1.5MPa in the magnetic separation process. The magnetic induction intensity is 900-5000 Gs.

In the flushing process provided by the invention, the ultrasonic frequency is 15000-30000Hz, and the ultrasonic power is 3000-4000W.

In the invention, the magnetism gathering medium is steel wool with the diameter of 0.05-0.5 mm. And in the separation cavity, the filling rate of the magnetic medium is 1-5 vol%.

The present invention will be described in detail below by way of examples. Wherein the washing efficiency is determined by the following method: weighing the mass of the unadsorbed magnetism gathering medium, and calculating the weight M₀(ii) a Weighing the magnetic medium (magnetic particles) obtained after the adsorption process is finished, and calculating the weight M₁(ii) a Washing the magnetic medium, weighing the dinner medium obtained after the washing process is finished, and counting the weight M₂Efficiency of washing%₁-M₂)/(M₁-M₀)×100％。

Example 1

Magnetic separation was performed according to the conditions listed in table 1.

(1) Energizing the magnet exciting coil 4 to generate a magnetic field, introducing the slurry containing magnetic particles into a separation cavity of a high-gradient magnetic separator H1, contacting with a magnetism gathering medium 9, carrying out magnetic separation, separating clear liquid and storing the clear liquid in a product tank;

(2) stopping slurry introduction, and closing the feed valve J1 and the discharge valve J2; the exciting coil 4 is powered off to eliminate the magnetic field; starting the ultrasonic generator 3 to generate ultrasonic waves, introducing flushing liquid and/or gas into a high-gradient magnetic separator H1 for backwashing, and separating magnetic particles accumulated and adsorbed in the magnetic medium 9;

wherein, step (2) adopts gas flushing and liquid flushing alternation mode to carry out specifically: under the ultrasonic action, firstly opening an air inlet valve J5 and an air release valve J6, and carrying out gas flushing on the high-gradient magnetic separator H1 by using gas; then closing an air inlet valve J5 and an air release valve J6, opening a flushing feed valve J3 and a flushing discharge valve J4, carrying out liquid flushing on the high-gradient magnetic separator H1 by using flushing liquid, and leading generated concentrated liquid to a concentrated liquid tank V3.

Comparative example 1

The method of example 1 was followed except that the magnetic separation device did not have an ultrasonic generator and the magnetic separation did not have ultrasonic conditions. The results are shown in Table 2.

Example 2

The magnetic separation unit was back-flushed on-line according to the conditions listed in table 1.

(1) Energizing the magnet exciting coil 4 to generate a magnetic field, introducing the slurry containing magnetic particles into a separation cavity of a high-gradient magnetic separator H1, contacting with a magnetism gathering medium 9, carrying out magnetic separation, separating clear liquid and storing the clear liquid in a product tank;

(2) stopping slurry introduction, and closing the feed valve J1 and the discharge valve J2; the exciting coil 4 is powered off to eliminate the magnetic field; starting the ultrasonic generator 3 to generate ultrasonic waves, introducing flushing liquid into a high-gradient magnetic separator H1 for backwashing, and separating magnetic particles accumulated and adsorbed in the magnetism gathering medium 9;

wherein, the step (2) is carried out in a liquid flushing mode: under the action of ultrasonic wave, a flushing feed valve J1 and a flushing discharge valve J4 are opened, a high-gradient magnetic separator H1 is flushed by flushing liquid, and the generated concentrated solution enters a concentrated solution tank V3.

Comparative example 2

The method of example 2 was followed except that the magnetic separation device did not have an ultrasonic generator and the magnetic separation did not have ultrasonic conditions. The results are shown in Table 2.

Example 3

The magnetic separation unit was back-flushed on-line according to the conditions listed in table 1.

(1) Energizing the magnet exciting coil 4 to generate a magnetic field, introducing the slurry containing magnetic particles into a separation cavity of a high-gradient magnetic separator H1, contacting with a magnetism gathering medium 9, carrying out magnetic separation, separating clear liquid and storing the clear liquid in a product tank;

(2) stopping slurry introduction, and closing the feed valve J1 and the discharge valve J2; the exciting coil 4 is powered off to eliminate the magnetic field; starting the ultrasonic generator 3 to generate ultrasonic waves, introducing gas into a high-gradient magnetic separator H1 for backwashing, and separating magnetic particles accumulated and adsorbed in the magnetic medium 9;

wherein, the step (2) is carried out in a gas flushing mode: under the action of ultrasound, the inlet valve J5 and the vent valve J6 were opened, and the high gradient magnetic separator H1 was flushed with gas.

Comparative example 3

The method of example 3 was followed except that the magnetic separation device did not have an ultrasonic generator and the magnetic separation did not have ultrasonic conditions. The results are shown in Table 2.

Example 4

The magnetic separation unit was back-flushed on-line according to the conditions listed in table 1.

(1) Energizing the magnet exciting coil 4 to generate a magnetic field, introducing the slurry containing magnetic particles into a separation cavity of a high-gradient magnetic separator H1, contacting with a magnetism gathering medium 9, carrying out magnetic separation, separating clear liquid and storing the clear liquid in a product tank;

(2) stopping slurry introduction, and closing the feed valve J1 and the discharge valve J2; the exciting coil 4 is powered off to eliminate the magnetic field; starting the ultrasonic generator 3 to generate ultrasonic waves, introducing flushing liquid and gas into the high-gradient magnetic separator H1 for gas-liquid mixed backwashing, and separating magnetic particles accumulated and adsorbed in the magnetism gathering medium 9;

wherein, step (2) adopts the mode that the gas-liquid mixture washed specifically to carry out: under the action of ultrasound, a flushing feed valve J3, a flushing discharge valve J4, an air inlet valve J5 and an emptying valve J6 are opened, flushing liquid and gas are used for carrying out gas-liquid mixed flushing on a high-gradient magnetic separator H1, generated concentrated solution enters a concentrated solution tank V3, and meanwhile, the flushed gas is emptied.

Comparative example 4

The method of example 4 was followed except that the magnetic separation device did not have an ultrasonic generator and the magnetic separation did not have ultrasonic conditions. The results are shown in Table 2.

TABLE 1

*: pressure difference between inlet and outlet of separation chamber

TABLE 2

*: pressure difference between inlet and outlet of separation chamber

As can be seen from the results in tables 1 and 2, in the examples using the apparatus and method of the present invention, compared with the comparative examples, when the same raw material is treated and the same separation result is obtained (the solid content of the separated clear liquid is the same), the washing time used in the examples is reduced, the washing efficiency is improved, the solid content of the concentrated solution is high (which indicates that the washing process removes more magnetic particles on the magnetic medium), and the back washing effect of separating the liquid-solid material containing fine magnetic particles is significantly improved.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.