CN117654124A - Method and device for separating and classifying particles - Google Patents

Abstract

The invention provides a method and a device for separating and classifying particles, which are characterized in that centrifugal force is applied to suspension containing particles, and second force perpendicular to the centrifugal sedimentation direction of the particles is superposed on the particles in centrifugal separation to generate secondary external acceleration, so that the particles generate Coriolis acceleration. By adopting the technical scheme of the invention, the Coriolis effect is utilized to generate secondary acceleration on particles in a centrifugal field which is vertical to the sedimentation direction of the particles in the fluid, the superposed acceleration enables the particles to generate motion and move vertical to the radial sedimentation motion direction of the particles in the fluid, so that friction among the particles can be reduced, smaller and lighter particles can be released, the separation and classification performances of the particles are improved, and more accurate particle size classification can be realized; especially under the condition of high concentration, the adverse effect of blocking the sedimentation of the particles is eliminated, and the separation and classification effects are better.

Description

Method and device for separating and classifying particles

Technical Field

The invention relates to the technical field of particle separation and classification, in particular to a hydrocyclone, and particularly relates to a particle separation and classification method and a device thereof.

Background

Hydrocyclones are common separation and classification equipment in mining and environmental processes. The working principle of the hydrocyclone is that the suspension is subjected to the action of centrifugal force by applying higher radial flow velocity to the suspension, so that the separation of particles is realized, and the particles are settled under the action of centrifugal acceleration perpendicular to the wall surface of the hydrocyclone. However, if the solid concentration is high, sedimentation is hindered, which means that the separation between the particles is hindered, and linear sedimentation movement is impossible; this effect is particularly pronounced if there are two or more particle mixtures of different densities, resulting in poor separation and classification using hydrocyclones.

It is well known that the movement of particles at high concentrations can be improved by superimposing the secondary movements. This secondary movement overcomes the stiction between particles so that the particles can move at different sedimentation rates depending on size, density and shape. The prior art separation processes typically employ additional forces to continuously or discontinuously subject the settled particles to improved classification of the particles. As in the up-flow classifier, the suspension is introduced into a water tank, the particles settle towards the bottom, the water flow is counter to the settling direction of the particles, which increases the relative velocity between the fluid and the particles and creates turbulence. The turbulent flow overcomes the static friction force between particles, thereby improving the integral sedimentation speed and the classification efficiency. Centrifugal jigs are one application of secondary forces to primary separate suspensions under centrifugal force, with particles settling radially toward the rotating drum wall and flushing water pulsed through openings in the drum wall. This counter flow results in the release of the particle mass, causing the particles to settle in their entirety at different rates. Yet another method is a centrifugal concentrator, where the suspension is introduced into a rotating bowl with openings in the bowl wall through which a continuous stream of water is introduced. The direction of the water flow is opposite to the main sedimentation direction, and turbulence is generated, so that static friction force between particles is overcome.

The prior solutions described above all transmit secondary forces by introducing additional fluid flow, which dilutes the material and increases the process water consumption. Moreover, the use of auxiliary fluid flows requires that the injected fluid has a total flow rate of approximately the suspension and that it is opposite to the particle sedimentation direction, which limits the application of gravity sedimentation in tanks and centrifugal equipment where the velocity gradient between the suspension and the separation cartridge wall is small. In the case of hydrocyclones, however, it is not possible to inject water counter to the sedimentation direction into the rotating flow of the suspension from the stationary outer wall.

Disclosure of Invention

Aiming at the technical problems, the invention discloses a particle separation and classification method and a device thereof, and the method utilizes the Coriolis effect, has better particle separation and classification effect, can be used for classifying treatment of suspension with high solid concentration, does not need extra flushing water, is more environment-friendly, and reduces cost.

In this regard, the invention adopts the following technical scheme:

a method for separating and classifying particles includes such steps as applying centrifugal force to the suspension containing particles, and applying a second force perpendicular to the centrifugal settling direction of particles to the particles in centrifugal separation to generate secondary external acceleration. Further, the secondary acceleration is a linear reciprocating acceleration, a constant centrifugal acceleration or a reciprocating tangential acceleration.

By adopting the technical scheme, the Coriolis effect is utilized to apply secondary external acceleration perpendicular to the centrifugal sedimentation direction to centrifugally separated fluid, so that the Coriolis acceleration of particles is realized, and the method for separating and classifying the particles is improved. Furthermore, the method reduces the concentration of light small particles in the underflow and heavy particles in the overflow, thereby improving the particle size distribution of the suspension and allowing the separation device to operate at higher solids concentrations.

As a further development of the invention, a hydrocyclone is used to apply a centrifugal force to the suspension, and a force parallel to the hydrocyclone cross section is applied to the hydrocyclone to produce a reciprocating linear acceleration, resulting in a radial velocity difference between the particles and the fluid.

As a further improvement of the present invention, the reciprocating linear acceleration includes a first acceleration generated in the forward movement of the hydrocyclone and a second acceleration generated in the return movement, the first acceleration being greater than the second acceleration. Further preferably, the first acceleration is 0.02 to 0.1 times the centrifugal acceleration caused by the fluid flow in the hydrocyclone, and the second acceleration is less than 0.02 times the centrifugal acceleration caused by the fluid flow in the hydrocyclone. The forward movement and the return movement are linear reciprocating movements, and further, the ratio of the first acceleration to the second acceleration is not less than 5.

As a further improvement of the invention, a hydrocyclone is used for applying centrifugal force to the suspension, and a second force is applied to the whole hydrocyclone, so that the hydrocyclone rotates around an external rotation shaft to generate centrifugal acceleration, and the included angle between the external rotation shaft and the axis of the hydrocyclone is not more than 30 degrees. When the included angle is 0 degrees, the external rotating shaft is parallel to the axis of the hydrocyclone.

As a further improvement of the invention, the centrifugal acceleration of the hydrocyclone is 0.02-0.1 times the centrifugal acceleration of the suspension in the hydrocyclone.

As a further improvement of the invention, a hydrocyclone is used to apply a centrifugal force to the suspension, and a second force is superimposed on the particles of the suspension to cause the particles to generate a reciprocating tangential acceleration, so as to cause a radial velocity difference between the particles and the fluid; the secondary angular velocity of the reciprocating tangential acceleration is 0.1-0.4 times the angular velocity of the fluid flow in the hydrocyclone, i.e. the second force generates the reciprocating tangential acceleration by applying 0.1-0.4 times the angular velocity of the fluid flow to the suspension in the hydrocyclone.

Further preferably, wherein the tangential direction results in a radial velocity gradient caused by an angular velocity difference between the particles and the fluid and a centrifugal acceleration difference.

As a further development of the invention, the particles of the suspension or parts thereof are magnetic particles, and the second force is a magnetic force generated by the application of a magnetic field parallel to the cross section of the hydrocyclone. Further, the magnetic field may be constant or may be changed regularly or irregularly.

The invention also discloses a particle separating and classifying device, which comprises a hydrocyclone and a Coriolis acceleration applying device, wherein the Coriolis acceleration applying device is used for superposing a second force perpendicular to the centrifugal sedimentation direction of particles in the hydrocyclone or the hydrocyclone to generate a secondary external acceleration so as to enable the particles to generate the Coriolis acceleration, and the particles are separated and classified by adopting the particle separating and classifying method of the suspension liquid.

As a further improvement of the invention, the coriolis acceleration applying device comprises a reciprocating driving platform and a reciprocating driving mechanism, wherein the hydrocyclone is fixed on the reciprocating driving platform, and the reciprocating driving mechanism is connected with the reciprocating driving platform to drive the reciprocating driving platform to reciprocate.

As a further improvement of the invention, the reciprocating driving mechanism comprises a driver and a driving rod, the hydrocyclone is fixed on a fixed frame, the fixed frame is fixed on a reciprocating driving platform, the driving rod is connected with the reciprocating driving platform, and the output end of the driver is connected with the driving rod to drive the driving rod to perform linear reciprocating motion and drive the reciprocating driving platform and the hydrocyclone to perform reciprocating motion.

As a further improvement of the invention, the coriolis acceleration applying device comprises a rotary platform and a rotary driving mechanism, wherein the hydrocyclone is fixed on the rotary platform, and the rotary driving mechanism is connected with the rotary platform and drives the rotary platform and the hydrocyclone thereon to perform rotary motion.

As a further improvement of the invention, the rotary platform comprises a support base, a rotary part and a support rod, wherein the support base is connected with the support rod through the rotary part, the support rod is connected with the hydrocyclone, and the rotary driving mechanism drives the hydrocyclone to rotate through driving the rotary part to rotate.

Further, the supporting rod is connected with the turntable; the hydrocyclone is assembled on the turntable.

Further, the turntable is of a circular ring structure.

As a further improvement of the invention, the coriolis acceleration applying device comprises a rotating platform and a rotation driving mechanism, wherein the hydrocyclone is positioned on the rotating platform, the rotating shaft of the rotating platform and the axis line are positioned on the same straight line, and the rotation driving mechanism drives the rotating platform to rotate so as to drive the hydrocyclone to rotate.

As a further improvement of the invention, the particles of the suspension or part of the particles are magnetic particles, the coriolis acceleration applying device comprises an external magnetic field generating device, the magnetic field direction of the external magnetic field generating device is perpendicular to the central axis direction of the water flow cyclone, and the external magnetic field generating device comprises a permanent magnet block or an electromagnet positioned outside the hydrocyclone.

Compared with the prior art, the invention has the beneficial effects that:

firstly, by adopting the technical scheme of the invention, the Coriolis effect is utilized to generate secondary acceleration on the particles in a centrifugal field which is vertical to the sedimentation direction of the particles in the fluid, and the superimposed acceleration enables the particles to generate motion which is vertical to the radial sedimentation motion direction of the particles in the fluid. Generally, as the particles settle towards the outer wall, the solids concentration of the suspension will increase, which increases the effect of hindered settling, i.e. particles with higher terminal settling velocity will squeeze lighter and smaller particles with lower terminal settling velocity, causing friction between the particles. The vertical Coriolis force is adopted to reduce friction among particles, so that smaller and lighter particles can be released, and the particle separation and classification performance is improved. Especially under the condition of high concentration, the adverse effect of blocking the sedimentation of the particles is eliminated, and the separation and classification effects are better.

Second, since coriolis forces are a function of particle mass, for particles of greater density or diameter, movement perpendicular to the centrifugal settling direction will be greater, increasing the classification effect, reducing the concentration of light small particles in the underflow and heavy particles in the overflow, further improving the release of smaller size or lower density particles in suspension under hindered settling conditions, improving the particle size distribution of the suspension in the cyclone, and allowing the hydrocyclone to operate at higher solids concentrations. And depending on the size and density of the particles, the angular velocity and the radius of rotation in the hydrocyclone, the coriolis acceleration may be greater than the external superimposed acceleration, the overall effect of which is to improve separation performance and particle classification. Since there are fewer small particles and light particles in the underflow and fewer large particles and heavy particles in the overflow, a more accurate size classification can be achieved.

Thirdly, by adopting the technical scheme of the invention, additional fluid is not required to be injected in the coriolis force transmission process, additional flushing water is not required, the solid concentration in the feeding of the hydrocyclone can be higher, dilution is avoided, and the process water consumption and the secondary treatment cost are reduced. The method is applicable to any existing hydrocyclone type, whether single or multiple unit hydrocyclone bank.

Drawings

FIG. 1 is a graph of the movement analysis of particles within a hydrocyclone in accordance with a first embodiment of the present invention.

FIG. 2 is a graph of a force analysis of particles within a hydrocyclone in accordance with a first embodiment of the present invention.

Fig. 3 is an analysis graph of coriolis acceleration vector aC of particles in a hydrocyclone at positions 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 °, and 315 ° of the hydrocyclone rotational path and a plot of coriolis acceleration as a function of radial position, where a) is the analysis graph of each position and b) is the plot of function.

Fig. 4 is a graph of the force analysis experienced by particles rotating with a suspension in a hydrocyclone under application of a secondary centrifugal acceleration (a2=rω2) according to a second embodiment of the invention.

Fig. 5 is an analysis of the direction of coriolis acceleration vector aC at positions 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 ° and 315 ° of the rotational path of a hydrocyclone, where a) is the analysis of each position and b) is a functional relationship, according to a second embodiment of the present invention.

Fig. 6 is a force analysis graph of particles in a hydrocyclone in accordance with a third embodiment of the present invention, wherein a) and b) are clockwise and counterclockwise, respectively.

Fig. 7 is a graph of coriolis acceleration direction as a function of superimposed reciprocating tangential acceleration frequency for particles in a hydrocyclone in accordance with a third embodiment of the present invention.

FIG. 8 is a schematic structural view of an apparatus for separating and classifying particles according to example 1 of the present invention.

Fig. 9 is a schematic view showing the structure of the apparatus for separating and classifying particles according to embodiment 1 of the present invention, which is connected to an underflow chute and an overflow chute.

FIG. 10 is a schematic structural view of an apparatus for separating and classifying particles according to example 2 of the present invention.

FIG. 11 is a schematic structural view of an apparatus for separating and classifying particles according to example 3 of the present invention.

FIG. 12 is a schematic view showing a modified structure of the apparatus for separating and classifying particles of example 3 of the present invention.

FIG. 13 is a schematic view showing the structure of a second modification of the apparatus for separating and classifying particles of example 3 of the present invention.

FIG. 14 is a schematic view showing the structure of a third modification of the apparatus for separating and classifying particles of example 3 of the present invention.

FIG. 15 is a schematic structural view of an apparatus for separating and classifying particles of example 4 of the present invention.

Fig. 16 is a schematic view showing the structure of a rotary driving device of the apparatus for separating and classifying particles of embodiment 4 of the present invention.

FIG. 17 is a schematic structural view showing the modified structure of the apparatus for separating and classifying particles of example 4 of the present invention.

Fig. 18 is a schematic diagram of the magnetic field generated by the external magnetic field generating device of embodiment 5 of the present invention.

Fig. 19 is a top view of the hydrocyclone of example 5 of the present invention.

FIG. 20 is a schematic structural view of an apparatus for separating and classifying particles according to example 5 of the present invention.

The reference numerals include:

101-hydrocyclone, 102-feeding interface, 103-underflow outlet, 104-overflow pipe, 105-reciprocating motion driving platform, 106-fixed frame, 107-fixed bracket; 111-driver, 112-driving rod; 121-underflow chute, 122-overflow chute; 123-underflow pipe joint, 124-overflow pipe joint;

200-hydrocyclone, 201-feed inlet, 202-cyclone underflow port, 203-underflow pipeline, 204-overflow pipe; 210-a rotating platform, 211-a supporting base, 212-a rotating part, 213-a supporting rod and 214-a turntable; 221-underflow collection channel;

301-hydrocyclone, 302-feed interface, 303-underflow outlet, 304-overflow pipe, 305-rotary platform, 306-fixed frame, 307-bracket, 308-pivot bearing; 309-fastening joint, 310-driving rod, 311-driver, 312-hollow shaft, 313-underflow outlet, 314-feeding pipe; 315-connecting pipe, 316-funnel, 317-underflow collecting funnel, 318-overflow pipe, 319-fixed collecting channel, 320-drain pipe;

401-an external magnetic field generating device, 402-a magnetic field intensity direction, 403-a permanent magnet; 410-hydrocyclone, 411-feed interface, 412-overflow, 413-underflow discharge.

Detailed Description

Preferred embodiments of the present invention are described in further detail below.

A method for separating and classifying particles includes such steps as applying centrifugal force to the suspension containing particles, and applying a second force perpendicular to the centrifugal settling direction of particles to the particles in centrifugal separation to generate secondary external acceleration. Wherein the secondary acceleration is linear reciprocating acceleration, constant centrifugal acceleration or reciprocating tangential acceleration.

Specifically, the suspension is treated by passing it through a hydrocyclone while applying a second force to the hydrocyclone as a whole, which force is superimposed in a direction perpendicular to the centrifugal sedimentation direction of the particles, causing the particles to develop a coriolis acceleration.

The coriolis force is an inertial force generated when a rotating object moves perpendicular to a rotational axis. The direction of coriolis force depends on the relationship of motion in the rotating system to the direction of rotation. If rotated clockwise, the coriolis force acts on the left side of the motion; if rotated counterclockwise, acts on the right side.

The coriolis force is superimposed on the rotating particles within the hydrocyclone by applying an acceleration to the hydrocyclone. Since the force to which the particles are subjected is the product of acceleration and mass, the velocity of the movement of the particles due to acceleration depends on the size or density of the particles, resulting in a velocity difference between the particles and the surrounding fluid.

The coriolis acceleration aC produced by the superposition of radial movements of the particles is a function of the product of the angular velocity ω and the superimposed radial velocity vr (ac=2×ω×vr). Therefore, the ratio of coriolis acceleration aC to external superimposed acceleration is amplified as a function of angular velocity ω.

In a first embodiment, a reciprocating linear acceleration parallel to the cross section of the hydrocyclone is applied to the hydrocyclone to create a radial velocity differential between the particles and the fluid. I.e. the hydrocyclone is forced in a linear direction to reciprocate in a direction parallel to the cross section of the hydrocyclone. The reciprocating motion may be divided into four parts, an acceleration motion in a linear direction, a reverse motion after rapid deceleration, a uniform motion, and a reverse motion after deceleration, wherein a ratio of a first acceleration generated in the forward motion of the hydrocyclone to a second acceleration generated in the return motion is not less than 5. By adopting the technical scheme, the positive radial acceleration or the negative radial acceleration is applied to the hydrocyclone, the speed difference between the particulate matters and the fluid is generated, and the speed difference is in direct proportion to the mass of the particulate matters, so that friction among the particulate matters in the sedimentation process is weakened or eliminated, better separation effect is achieved, and meanwhile, the water consumption for separation is reduced.

Further, the first acceleration is 0.02 to 0.1 times the centrifugal acceleration caused by the fluid flow in the hydrocyclone, and the second acceleration is less than 0.02 times the centrifugal acceleration caused by the fluid flow in the hydrocyclone.

As shown in fig. 1, the particles of the suspension in the hydrocyclone rotate about the axis z with a radius r and an angular velocity ω, and the whole hydrocyclone is subjected to an external acceleration a2 in the y-axis direction, resulting in a secondary velocity v2 of the particles in the hydrocyclone in the-y-axis direction. Under the action of the angular velocity in the clockwise direction, coriolis acceleration aC in the x-axis direction is generated. The value of coriolis acceleration aC is equal to twice the product of angular velocity and secondary velocity, i.e., ac=2×ω×v2.

The forces to which the particles rotating with the suspension in the hydrocyclone are subjected are shown in figure 2, it being seen that the secondary acceleration a2 is applied in a linear motion parallel to the y-axis, resulting in a secondary velocity v2 of the particles. Wherein the radial portion vr of the secondary velocity is related to the coriolis force. For example, radial velocity vr portions and the resulting coriolis accelerations aC are shown at the 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 °, and 315 ° positions of the rotational path.

The coriolis velocity component vC is to the left of the radial velocity component vr as the particles rotate clockwise within the hydrocyclone. At 0 ° and 180 °, coriolis acceleration is greatest when the radial velocity vector vr is parallel to the Y-axis. At 90 ° and 270 °, the secondary velocity does not cause radial displacement of the particles and therefore no coriolis acceleration is observed.

Fig. 3 shows the coriolis acceleration vector aC superimposed with the secondary linear acceleration in the direction of the hydrocyclone rotational paths 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 ° and 315 °. The direction of coriolis acceleration depends on the position of the particles in the path of rotation. The maximum coriolis acceleration is located at the 0 deg. and 180 deg. positions. The zero points are located at 90 deg. and 270 deg. positions. The direction of coriolis acceleration is reversed twice for one revolution at the 90 deg. and 270 deg. positions. When plotted, the coriolis acceleration is plotted as a function of radial position as a sinusoid with maxima at 0 ° and 180 ° and turning points at 90 ° and 270 °.

In addition, since the superimposed external acceleration is intermittently applied with the reciprocating motion, the coriolis acceleration also varies with time. The advantage of linear acceleration is that the frequency of change of the coriolis force is high at moderate intensities. This method is applicable to larger particles and to less regular non-spherical particles.

Example 1

A schematic diagram of an apparatus for performing particle separation and classification in accordance with the first embodiment described above is shown in fig. 8, which includes a hydrocyclone 101 and a coriolis acceleration applying device, which is a device for driving the hydrocyclone 101 to perform a reciprocating motion.

The hydrocyclone 101 comprises a feed inlet 102, an underflow outlet 103 and an overflow pipe 104, and the hydrocyclone 101 is fixed to a fixed frame 106, in particular by means of a fixed support 107 to the fixed frame 106. The fixed frame 106 is fixed to the reciprocating drive platform 105. The reciprocating drive platform 105 is fixed in vertical direction and can only move horizontally.

The reciprocating driving means reciprocates the reciprocating driving platform 105, and includes a driver 111 and a driving rod 112. The drive rod 112 is coupled to the reciprocating drive platform 106. Further, the driver 201 includes a motor equipped with a gear box, and an output end of the driver 111 is connected to the driving rod 112, so as to drive the driving rod 112 to perform linear reciprocating motion, and transmit the reciprocating motion to the hydrocyclone 101 through the reciprocating driving platform 105.

Further, as shown in fig. 9, an underflow chute 121 is disposed below the underflow outlet 103 of the hydrocyclone 101, the underflow of the hydrocyclone 101 is collected by the underflow chute 121, and the overflow pipe 104 of the hydrocyclone 101 is discharged toward the overflow chute 122, and the overflow is collected in the overflow chute 302. Further, the underflow chute 301 and the overflow chute 122 may be fixed to an external frame and connected to an external pipe via an underflow pipe connection 123 and an overflow pipe connection 124, respectively.

Example 2

On the basis of embodiment 1, this embodiment may be further extended, as shown in fig. 10, a plurality of hydrocyclones 101 may be fixed on the reciprocating driving platform 105, each hydrocyclone 101 is fixed on the reciprocating driving platform 105 through a fixed frame 106, and the plurality of hydrocyclones 101 may be driven by one driver 111 to perform reciprocating motion. The superimposed coriolis motions in this embodiment will enhance the separation and classification performance of each hydrocyclone 101 on particles.

In a second embodiment, a second force is applied to the hydrocyclone as a whole, causing the hydrocyclone to rotate about an external rotation axis which is at an angle of no more than 30 degrees to the axis of the hydrocyclone to generate centrifugal acceleration. When the included angle is 0 degrees, the external rotating shaft is parallel to the axis of the hydrocyclone. Further preferably, the centrifugal acceleration of the hydrocyclone is 0.02-0.1 times the centrifugal acceleration of the suspension in the hydrocyclone. In this scenario, the coriolis force acts as a superposition with the centrifugal acceleration.

In such embodiments, the high acceleration of the centrifugal motion may create a radial velocity gradient between the particles and the fluid. The difference in radial velocity changes the centrifugal acceleration, which in turn causes a radial velocity gradient to be created between particles of different sizes or densities, which produces coriolis acceleration as a function of the product of radial velocity and angular velocity. For a hydrocyclone circulating clockwise, the corresponding coriolis acceleration is perpendicular to the left side of the radial velocity, and for a counter-clockwise circulation, perpendicular to the right side of the radial velocity.

Coriolis motion causes a pulsating lateral motion of the particles as they settle out toward the outer wall. Since the coriolis force is a function of the mass and shape of the particles, force gradients can be created between particles of different diameters and densities, thereby overcoming the static friction between contacting particles. The result is that lighter and smaller particles are released from the higher concentration suspension into the overflow of the hydrocyclone, thus overcoming the so-called hindered settling effect.

Fig. 4 shows the forces to which particles rotating with the suspension in the hydrocyclone are subjected under the application of a secondary centrifugal acceleration (a2=rω2). The secondary centrifugal acceleration is generated by rotation of the hydrocyclone about an axis z2, the hydrocyclone rotation axis z1 being substantially parallel to the secondary rotation axis z 2. The superimposed secondary centrifugal acceleration produces a secondary velocity v2 that is radial to the axis z 2.

The secondary velocity vector v2 may be divided into a vector vr radial to the hydrocyclone axis z1 and a vector vr perpendicular thereto. Only the velocity vector vr is related to the coriolis effect. For example, the radial velocity vector vr and the resulting coriolis acceleration aC are located at 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 °, and 315 °, respectively, of the rotational path. The coriolis acceleration aC is directed to the left of the radial velocity vector vr as it rotates clockwise in the hydrocyclone.

Fig. 5 shows the direction of coriolis acceleration vector aC at the 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 °, and 315 ° positions of the hydrocyclone rotational path, with superimposed secondary centrifugal acceleration. The direction of coriolis acceleration depends on the position of the particles in the path of rotation.

The coriolis acceleration maxima occur at 90 deg. and 270 deg. positions, with the secondary velocity v2 being parallel to the hydrocyclone axis x. These positions are the intersection of the particle orbit and the outer rotation orbit. At the track intersection, the direction of coriolis acceleration is reversed twice during one revolution.

The advantage of the secondary centrifugal acceleration is that the coriolis force is greater and the portion of the coriolis acceleration that reverses direction is shorter. This method is applicable to smaller particles or more regularly shaped, more spherical particles.

In the specific embodiment, the hydrocyclone or the cyclone group can be vertically arranged on the rotating platform, and the rotating platform is driven to rotate clockwise or anticlockwise through the driving mechanism. Depending on the position of the particles within the hydrocyclone and their direction of circulation, positive or negative radial acceleration is applied to cause the velocity differential between the particles and the fluid to be proportional to the mass of the particles. The radial superposition generates Coriolis force perpendicular to the sedimentation direction, and can reduce or eliminate static friction force between particles on the sedimentation path, thereby achieving better separation effect and lower process water consumption. See example 3 for details.

Example 3

A schematic of an apparatus for effecting the above-described second embodiment, particle separation and classification, is shown in fig. 11, which includes a hydrocyclone 200 and a coriolis acceleration applying device for generating a centrifugal acceleration for driving the hydrocyclone 201 to rotate about an external rotation axis.

The hydrocyclone 200 is positioned on a rotary platform 210, the rotary platform 210 comprises a support base 211, a rotary part 212, a support rod 213 and a turntable 214, the support base 211 is connected with the support rod 213 through the rotary part 212, and the support rod 213 is connected with the turntable 214; the hydrocyclone 201 is mounted on the turntable 214, and when the rotating platform 210 rotates, the turntable 214 is driven to rotate by driving the rotating part 212 to rotate, so as to drive the hydrocyclone 200 to rotate clockwise or anticlockwise, and the particles moving at high speed inside the hydrocyclone 200 are subjected to the action of coriolis force.

As shown in fig. 11, the hydrocyclone 200 is provided with a feed inlet 201, a cyclone underflow port 202 and an overflow pipe 204 connected with the overflow port, and the cyclone underflow port 202 leads high-concentration large particles into an underflow collecting channel 221 through an underflow pipe 203; the outlet of the overflow tube 204 is directed toward the overflow collection channel 222, and the overflow tube 204 drains the low concentration fine particles into the overflow collection channel 222. The hydrocyclone 200 may be a single hydrocyclone or a bank of hydrocyclones in different combinations. In this example two hydrocyclone sets are shown.

The structure of the rotary stage 210 may take a variety of forms. As shown in fig. 12, a compact coriolis force enhanced outer centrifugal acceleration hydrocyclone device is shown, the turntable 214 is a hollow ring, the overflow pipe 204 of the hydrocyclone 2 is near the center of the plane of the turntable 214, the central axes of the overflow collecting channel 222 and the underflow collecting channel 221 are on the same straight line with the axial line of the turntable 214, and in this embodiment, each component is compact in design and occupies small space. In order to more clearly show the structural relationship, the overflow collecting channel 222 is arranged above the turntable 214, the underflow collecting channel 221 is arranged below the turntable 214, and in practical implementation, it is feasible to uniformly arrange the overflow collecting channel 222 and the underflow collecting channel 221 above and below the turntable 214, or simultaneously arrange them outside the turntable 214 to form a circular ring structure.

Further, as shown in fig. 13, the turntable 214 may be a complete disk structure, or may be a structure that can be stably fixed and rotated, such as a regular polygon or a polygonal ring, according to the number of installed hydrocyclone units.

Further, as shown in fig. 14, when the hydrocyclone 200 is small and light, the structure of the rotary platform 210 can be simplified, i.e., the turntable 214 is removed, and the hydrocyclone is directly mounted on the support bar 213.

In a third embodiment, the second force is superimposed on the hydrocyclone to superimpose the particles on the reciprocating tangential acceleration. The high acceleration of the forward motion creates a tangential velocity gradient between the particles and the fluid. The difference in tangential velocity changes the centrifugal acceleration, which in turn results in a radial velocity gradient between particles of different sizes or densities. This results in coriolis acceleration as a function of the product of radial velocity and angular velocity. The superimposed tangential velocity difference between the particles and the fluid results in a difference in radial centrifugal acceleration and radial velocity gradient. The corresponding coriolis acceleration depends on the tangential velocity gradient and the particle orbit radius.

Further, the secondary angular velocity of the reciprocating tangential acceleration is 0.1-0.4 times the normal angular velocity of the fluid in the hydrocyclone.

The forces acting on the particles rotating with the suspension with superimposed reciprocating tangential accelerations are shown in fig. 6. The direction of coriolis acceleration is independent of the position of the particles in the path of rotation.

For the case of clockwise rotation in the hydrocyclone and overlapping tangential velocity directions being the same, the direction of the coriolis velocity component vC is negative, parallel to the x-axis; for the case of clockwise rotation in the hydrocyclone and superimposed tangential velocity direction opposite, the direction of the coriolis velocity component vC is positive, parallel to the x-axis.

As shown in fig. 7, the direction of coriolis acceleration is dependent only on the direction of the external tangential acceleration and is the same at all points along the path of particle rotation. The direction of the coriolis velocity component varies sinusoidally with the direction of the tangential acceleration, with zero at the change in direction of the external acceleration. Since coriolis velocity is a function of radius, tangential reciprocating acceleration is most suitable for larger diameter hydrocyclones.

The specific implementation mode is that the traditional hydrocyclone is vertically arranged on a rotary platform, and the center line of the hydrocyclone is positioned on the rotary shaft of the platform. The rotating platform performs reciprocating rotation, and the acceleration is high during forward movement and low during backward movement. The forward direction of the platform is the same as the circulating flow direction inside the hydrocyclone. If the hydrocyclone is operated in a clockwise direction, the forward direction of the platform is clockwise. If the hydrocyclone flows in a counter-clockwise direction, the forward direction of the platform is counter-clockwise.

When the rotating platform accelerates forward, the tangential movement direction of the particles is opposite to the circulating flow direction, and the radial speed direction is towards the rotating shaft. For a hydrocyclone circulating clockwise, the corresponding coriolis acceleration is perpendicular to the left side of the radial velocity, and for a counter-clockwise circulation, perpendicular to the right side of the radial velocity. Coriolis motion causes a pulsating lateral motion of the particles as they settle out toward the outer wall. Since the coriolis force is a function of the mass and shape of the particles, force gradients can be created between particles of different diameters and densities, thereby overcoming the static friction between contacting particles. The result is that lighter and smaller particles are released from the higher concentration suspension into the overflow of the hydrocyclone, thus overcoming the so-called hindered settling effect.

Example 4

The apparatus for effecting the third embodiment described above for effecting particle separation and classification comprises a hydrocyclone 301 and a coriolis acceleration applying means for rotating the hydrocyclone 301 to produce tangential acceleration.

As shown in fig. 15, the hydrocyclone 301 is provided with a feed port 302, an underflow outlet 303 and an overflow pipe 304, the hydrocyclone 301 is fixed to a fixed frame 306 by a bracket 307, the fixed frame 306 is fixed to a rotary platform 305, and the rotary platform 305 is mounted on a pivot bearing 308.

As shown in fig. 16, a rotary drive device coupled to the rotary platform 305 includes a fastening tab 309, a drive rod 310, and a driver 311. The rotary platform 305 is fixed on a hollow shaft 312, and the driver 311 drives the rotary platform 305 to rotate through a driving rod 310, and the hollow shaft 312 rotates in a pivot bearing 308. The bottom of the pivot bearing 308 is provided with an underflow outlet 313 as an angular space, and the feed pipe 314 is located in the center of the underflow outlet 313.

Example 5

On the basis of embodiment 4, the main improvement of this embodiment is the pipe connection. As shown in fig. 17, which is a schematic diagram of the piping connection of the hydrocyclone 301, the hydrocyclone 301 is mounted on a rotating platform 305 above a pivot bearing 308. The fixed frame 306 is hollow, the feed pipe 314 enters from the lower part of the pivot bearing 308 through the hollow shaft 312 and is connected with the fixed frame 306 on the rotating platform 305 through the connecting pipe 315, and is communicated with the hollow part of the fixed frame 306, one end of the feed pipe 314 is connected with the top of the fixed frame 306, and the other end is connected with the inlet of the hydrocyclone 301.

The underflow from the underflow outlet 303 exits into a funnel 316, flows through the annular space between the hollow shaft 312 and the feedpipe 314, and exits into the underflow collection funnel 317. The overflow tube 318 extends to a fixed collection channel 319 and the overflow is discharged through a drain tube 320.

In a fourth embodiment, the coriolis force is applied using magnetic force in a manner that is directed to the separation of magnetic particles (e.g., magnetite) or to a portion of the particles being magnetic particles. Specifically, by applying a magnetic field parallel to the section of the hydrocyclone, that is, the direction of the magnetic field is perpendicular to the central axis direction of the hydrocyclone, the external magnetic field can superimpose linear acceleration on the magnetic particles, so that the magnetic particles (such as magnetite) are accelerated under the influence of the coriolis effect, thereby generating magnetic force and secondary tangential acceleration on the magnetic particles, and optimizing the performance of separating and classifying the particles in the hydrocyclone by utilizing the coriolis effect. The magnetic field may be constant or may vary regularly or irregularly.

In this embodiment, the magnetic particles in the hydrocyclone are influenced by the magnetic force by the addition of an external magnetic field, the magnetic particles being magnetically influenced in the magnetic field, a change in radial movement taking place. In the rotational state, a change in radial motion occurs again, creating a coriolis effect, and therefore particles with superimposed linear accelerations experience motion perpendicular to radial sedimentation. The coriolis forces acting on the particles due to the magnetic forces also reduce the static friction between the particles during settling, allowing smaller and lighter particles to better enter the overflow of the hydrocyclone and larger particles to enter the underflow.

In the sedimentation process of the traditional hydrocyclone, the phenomenon of collision and agglomeration of small particles and large particles can occur. According to the technical scheme, the traditional hydrocyclone is modified in such a way, static friction force between large particles and small particles is overcome by means of Coriolis force, particle agglomeration phenomenon is avoided, the large particles and the small particles can be separated, more small particles can be discharged through the top overflow port, meanwhile, the large particles can be smoothly discharged through the bottom flow discharge port, and the integral separation effect is optimized.

For a hydrocyclone circulating clockwise, the corresponding coriolis acceleration is perpendicular to the left side of the radial velocity, and for a counter-clockwise circulation, perpendicular to the right side of the radial velocity.

As the coriolis force is a function of mass. Particles with a higher density or a larger diameter are more affected, so that static friction force between particles is improved, and better separation and classification effects can be obtained.

Example 6

The apparatus for performing the particle separation and classification according to the third embodiment includes a hydrocyclone and a coriolis acceleration applying device, which is an external magnetic field generating device 101.

As shown in fig. 18, the external magnetic field generating device 401 may be two permanent magnetic blocks or a non-permanent electromagnetic block, and the magnetic field strength direction 402 is parallel to the x-axis and parallel to the feeding direction of the feed port 411 of the hydrocyclone 410 and perpendicular to the rotation axis z-axis of the hydrocyclone.

A top view of the hydrocyclone is shown in figure 19 in which the particles are moving around the z-axis with a radius r and an angular velocity ω. Because of the external magnetic field, the magnetic particles are subjected to magnetic force, and secondary acceleration a2 is generated along the-y axis direction, and vr is the fluid velocity direction +y. In the case where the angular velocity ω is clockwise, coriolis acceleration ac in the-x direction is generated.

As shown in fig. 20, a structure diagram of an external magnetic field of a hydrocyclone is shown, a hydrocyclone 410 is provided with a feed inlet 411, an overflow inlet 412 and an underflow discharge outlet 412, and an external magnetic field generating device 401 includes two permanent magnetic blocks 403, or may be a non-permanent electromagnetic block.

The two permanent magnet blocks 403 are vertically arranged on the outer wall of the separation area of the hydrocyclone, and do not have any influence on the work of the concentration area of the hydrocyclone. Further, when the permanent magnet blocks 403 are parallel to the axial direction of the hydrocyclone 410, the longitudinal length of the permanent magnet blocks 403 is not greater than the length of the straight section of the hydrocyclone 410, so that a magnetic field with the direction perpendicular to the rotation axis is generated inside the hydrocyclone 410. When the hydrocyclone 410 is operated, the magnetic particles are attracted by the magnetic force in the magnetic field, thereby generating a downward acceleration. As a result of the magnetic particles being subjected to a magnetic force, the radial movement is changed, whereby a coriolis force is generated. If the magnetic particles rotate anticlockwise in the hydrocyclone, the resulting coriolis acceleration acts on the right side of the particles, which is related to the mass of the particles, and by means of mass differentiation, particles of different sizes are separated.

The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.

Claims (10)

1. A method of particle separation and classification, characterized by: and applying a centrifugal force to the suspension containing the particles, and superposing a second force perpendicular to the centrifugal sedimentation direction of the particles on the particles in centrifugal separation to generate a secondary external acceleration, so that the particles generate a Coriolis acceleration.

2. The method of particle separation and classification as claimed in claim 1, wherein: the centrifugal force is applied to the suspension by a hydrocyclone, and a force parallel to the cross section of the hydrocyclone is applied to the hydrocyclone to generate reciprocating linear acceleration, so that a radial velocity difference is generated between the particles and the fluid.

3. The method of particle separation and classification as claimed in claim 2, wherein: the reciprocating linear acceleration includes a first acceleration generated in a forward motion of the hydrocyclone and a second acceleration generated in a return motion; the ratio of the first acceleration to the second acceleration is not less than 5; the first acceleration is 0.02 to 0.1 times the centrifugal acceleration caused by the fluid flow in the hydrocyclone, and the second acceleration is less than 0.02 times the centrifugal acceleration caused by the fluid flow in the hydrocyclone.

4. The method of particle separation and classification as claimed in claim 1, wherein: and applying a centrifugal force to the suspension by using the hydrocyclone, and applying a second force to the whole hydrocyclone, so that the hydrocyclone rotates around an external rotating shaft to generate centrifugal acceleration, wherein an included angle between the external rotating shaft and the axis of the hydrocyclone is not more than 30 degrees.

5. The method of particle separation and classification as claimed in claim 4 wherein: the centrifugal acceleration of the hydrocyclone is 0.02-0.1 times of the centrifugal acceleration of the suspension in the hydrocyclone.

6. The method of particle separation and classification as claimed in claim 1, wherein: applying a centrifugal force to the suspension by using a hydrocyclone, and superposing a second force on the particles of the suspension to generate reciprocating tangential acceleration of the particles, so that a radial speed difference is generated between the particles and the fluid; the secondary angular velocity of the reciprocating tangential acceleration is 0.1 to 0.4 times the angular velocity of the fluid flow in the hydrocyclone.

7. The method of particle separation and classification as claimed in claim 1, wherein: the particles of the suspension or some of them are magnetic particles and the second force is a magnetic force generated by the application of a magnetic field parallel to the cross section of the hydrocyclone.

8. A particle separation and classification apparatus, characterized by: comprising a hydrocyclone or a coriolis acceleration applying device for superposing particles in the hydrocyclone or the hydrocyclone with a second force perpendicular to the direction of centrifugal sedimentation of the particles, the particles being separated and classified by a method for separating and classifying particles of a suspension according to any of claims 1-7.

9. The particle separation and classification apparatus of claim 8, wherein: the Coriolis acceleration applying device comprises a reciprocating driving platform and a reciprocating driving mechanism, the hydrocyclone is fixed on the reciprocating driving platform, and the reciprocating driving mechanism is connected with the reciprocating driving platform and drives the reciprocating driving platform to reciprocate;

or the Coriolis acceleration applying device comprises a rotary platform and a rotary driving mechanism, wherein the hydrocyclone is fixed on the rotary platform, and the rotary driving mechanism is connected with the rotary platform and drives the rotary platform and the hydrocyclone thereon to perform rotary motion;

or the coriolis acceleration applying device comprises a rotating platform and a rotation driving mechanism, the hydrocyclone is positioned on the rotating platform, the rotating shaft of the rotating platform and the axis line are positioned on the same straight line, and the rotation driving mechanism drives the rotating platform to rotate so as to drive the hydrocyclone to rotate.

10. The particle separation and classification apparatus of claim 8, wherein: the particles of the suspension or part of the particles are magnetic particles, the Coriolis acceleration applying device comprises an external magnetic field generating device, the magnetic field direction of the external magnetic field generating device is perpendicular to the central axis direction of the hydrocyclone, and the external magnetic field generating device comprises a permanent magnet block or an electromagnet positioned on the outer side of the hydrocyclone.