CN116510842A - A high-efficiency grinding system and method for ultrasonically enhanced grinding - Google Patents

Abstract

The invention belongs to the technical field of ore grinding in mineral processing, and discloses a high-efficiency ore grinding system and method for ultrasonically enhanced ore grinding. A high-efficiency grinding system for ultrasonically enhanced grinding, including a grinding device, an ultrasonic generating device, and a classifying device; materials enter the grinding device through a material inlet, and the grinding device works synchronously with the ultrasonic generating device. The ultrasonic generator is attached to the barrel wall of the mill. The system of the present invention can use ultrasonic waves to disperse the agglomerated particles, strengthen the degree of dissociation of ore particles during grinding, remove the fine mud on the particle surface and clean the oxide film on the mineral surface, and improve the production efficiency of ore grinding Degree of dissociation from grinding products.

Description

A high-efficiency grinding system and method for ultrasonically enhanced grinding

technical field

The invention belongs to the technical field of mineral processing, and relates to a high-efficiency grinding system and method for ultrasonically enhanced grinding.

Background technique

Mineral resources are important strategic materials for national economic construction and social development. With the development and utilization of mineral resources, high-quality mineral resources are becoming less and less, and some minerals with fine particle size and complex mineral composition are gradually being developed. For this part of mineral resources Resources generally need to be finely ground and ultrafine to allow the minerals to dissociate. In the beneficiation process, the particle size of ore particles needs to be reduced through crushing and grinding operations in the preparation stage, so that the gangue and valuable minerals can be dissociated. During the grinding process, the power consumption of the grinding equipment is very high, and reducing the energy consumption of the grinding operation is of great significance to improve the economic benefits of the concentrator. With the rapid development of grinding equipment in recent years, the agitator mill, as a high-efficiency fine grinding equipment, has been gradually applied to mineral processing plants such as lead-zinc ore, copper ore, gold ore and iron ore. However, during the fine grinding process, the selective dissociation between valuable minerals and gangue is poor, and some of the finely ground gangue minerals are easy to cover the surface of valuable minerals through adsorption and agglomeration, resulting in subsequent separation. A drop in efficiency. Studies have found that ultrasonic waves help to clean the slime covering the surface of valuable minerals, and expand the cracks between valuable minerals and gangue minerals during the grinding process, improve the monomer dissociation degree of minerals, and reduce grinding energy consumption .

Contents of the invention

The purpose of the present invention is to provide a system and method based on the ultrasonic-strengthened grinding process, which utilizes the ore particles to produce micro-cracks in the grinding process, and the phase interface bonding force between crystal minerals is low. The device constitutes an enhanced grinding system. By adding stable ultrasonic waves in the grinding chamber to expand the ore particles to produce micro-cracks, the degree of dissociation of ore particles during grinding is further strengthened, and the degree of monomer dissociation of the grinding product is improved. The agglomerated gangue minerals and valuable minerals are broken up, the gangue particles covered on the surface of valuable mineral particles are removed, the oxide film on the mineral surface is cleaned, the grinding production efficiency is improved, and qualified grinding is provided for subsequent separation. Minerals.

A high-efficiency grinding system for ultrasonically enhanced grinding, including a grinding device, an ultrasonic generating device and a classifying device;

The ore grinding device includes a motor, a reducer, an agitator, a cylinder, a feeding port, a sieve plate and a discharge port; the cylinder is fixed and vertical to the ground, and there are agitators and grinding media in the cylinder, and the bottom of the cylinder is provided with The feeding pipe is fed through the feeding pump of the stirring mill; the top of the cylinder is provided with a discharge port, and the connection between the discharge port and the cylinder is provided with a sieve plate;

The ultrasonic generating device includes an ultrasonic generator, an ultrasonic transducer and a horn, the ultrasonic generator is connected with several ultrasonic transducers, the ultrasonic transducer is connected with the horn, and the horn is embedded in the stirring On the cylinder wall of the mill, the direction of the sound wave generated is perpendicular to the direction of the movement of the ore particles in the grinding chamber;

The classification device includes a slurry buffer tank, a cyclone feed pump and a hydrocyclone connected in sequence, the slurry buffer tank is connected to the discharge port of the grinding equipment, and the upper end of the hydrocyclone is connected to the next-level equipment. The lower end of the hydrocyclone is connected with the feeding pipe.

Further, the feeding rate of the grinding device is 20-40 g/(min·cm ² ), that is, the mass of material passing through the cross section of the cylinder per square centimeter per minute.

Furthermore, the motor in the grinding device is connected with the reducer, the reducer is connected with the agitator, and the agitator and the cylinder are on a central axis. The agitator is of spiral type, pin-pin type or disc type; when the agitator rotates, the edge speed is 2.5-3.5m/s.

Further, in the barrel, the piled volume of grinding media accounts for 60%-80% of the effective volume of the barrel, and the distance between the upper part of the barrel and the discharge port of the grinding media is 0.5-0.8mm.

further,

The ratio of the diameter of the grinding media in the cylinder is determined according to the content of -0.074mm particles in the feed:

When the content of -0.074mm particles accounts for 40% to 50%, the diameter ratio of grinding media is 10mm: 15mm: 20mm = 1:1:3;

When the content of -0.074mm particles accounts for 50% to 60%, the diameter ratio of grinding media is 10mm: 15mm: 20mm = 1:2:2;

When the content of -0.074mm particles accounts for 60% to 70%, the diameter ratio of grinding media is 10mm: 15mm: 20mm = 2:2:1;

When the content of -0.074mm particles accounts for 70% to 80%, the diameter ratio of grinding media is 10mm: 15mm: 20mm = 3:1:1;

Further, in the barrel, during the grinding process of the ore particles, the concentration of the slurry is 30%-60%;

Further, the sieve hole size of the sieve plate is smaller than the diameter of the grinding medium, so as to prevent the grinding medium from flowing out with the slurry.

The vibration frequency of the ultrasonic generator is 40-60Hz, and the sound pressure level is 80-120dB.

The included angle between the horns at the same horizontal height on the barrel is 90°, 120° or 180°.

The position where the horn is embedded in the cylinder wall of the stirring mill is 1/2 between the two rod pins of the agitator, and the surrounding area is sealed with wear-resistant rubber so that it can be replaced after wear and tear. The installation direction of the horn is the same as The direction of slurry flow is vertical.

The hydrocyclone includes a cone, a feed port, an overflow pipe and a grit port.

In the above system, the grading size of the hydrocyclone is determined according to the particle size of the valuable mineral particles in the ore, the degree of dissociation and the requirement of the sorting operation for the particle size of the grinding product.

A working method of a high-efficiency grinding system with ultrasonic enhanced grinding. The material enters the grinding chamber along the tangent line through the feeding pipe at the bottom of the grinding device. The agitator rotates to drive the grinding medium to move to produce grinding. The ultrasonic generator and the changer The transducer is connected with the transducer, the transducer converts the electric energy into vibration, and transmits it to the ore particles in the barrel through the horn. The direction of the ultrasonic wave generated by the ultrasonic wave is perpendicular to the direction of the flow of the particles in the grinding chamber; so that the material is ground at the same time The dissociation and crushing are strengthened by ultrasonic waves, and then the materials discharged from the discharge port of the grinding device pass through the slurry buffer tank, and then are sent into the hydrocyclone by the cyclone feeding pump for classification. The overflow pipe of the cyclone enters the next operation, and the over-coarse grinding product enters the mill through the sand outlet of the hydrocyclone for regrinding.

Principle of the present invention is:

Mineral resources with fine particle size and difficult dissociation are finely ground in the stirring mill. The function of ultrasonic waves is to expand the ore particles to produce micro-cracks during the grinding process, further strengthening the degree of dissociation of ore particles during grinding, and at the same time Disperse the agglomerated gangue minerals and valuable minerals, remove the gangue particles covering the surface of valuable mineral particles, clean the oxide film on the mineral surface, and transport the grinding products to the hydrocyclone for classification , the qualified grinding product particle size enters the sorting operation through the overflow port, while the coarse-grained grinding product returns to the mill for regrinding, which not only ensures the dissociation effect of the grinding product, but also improves the quality of the grinding product. monomer dissociation.

The beneficial effects of the present invention are:

Compared with conventional grinding and grading systems and methods, the system and method involved in the present invention can effectively dissociate valuable minerals from mineral resources with fine particle size and difficult dissociation, and improve subsequent separation efficiency and Effect: using a stirring mill to grind it can improve the microcracks of ore particles, and the material is in a fluidized state when it is ground in the grinding chamber, which improves the uniformity of the sound wave effect and can agglomerate the particles Break up and clean the slime and oxide film covered on the dissociation surface, expand the micro-cracks between the valuable minerals and gangue minerals in the ore particles, improve the dissociation degree of the grinding product monomer, and prepare for the subsequent separation operation Qualified feeding materials are provided; the system and method have simple flow and simple control process, and have good prospects in future industrial applications.

Description of drawings

Fig. 1 is a kind of system diagram based on ultrasonic enhanced grinding process in the embodiment of the present invention;

Figure 2 is the distribution diagram of the horns in the embodiment of the present invention on the horizontal plane of the cylinder and the structural diagram of the horns embedded in the cylinder, a-the angle between the horns at the same level is 180°, b-the same level The angle between the height of the horns is 120°.

The reference signs are as follows:

101 ultrasonic generator; 102 ultrasonic transducer; 103 horn; 201 stirring mill feeding pump; 202 cyclone feeding pump; 3 pulp buffer pool; 401 motor; 402 reducer; 404 grinding medium; 405 agitator; 406 cylinder; 407 discharge port; 408 sieve plate; 501 cone; 502 feed port; 503 overflow pipe;

Detailed ways

One of the specific implementation methods:

A system and method based on an ultrasonic enhanced grinding process, comprising the following process steps:

1. Feed the material and water crushed to -0.074mm, with a content of 40% to 80%, into the mill through the tangential feeding pipe 2 at the bottom of the cylinder. At this time, the mass ratio of the material in the pulp is 30% to 60%. ;

2. The barrel of the mill is equipped with a grinding medium, and the pile volume of the grinding medium accounts for 60% to 80% of the effective volume of the barrel. The diameter of the grinding medium is determined according to the particle size distribution of the feed material. The test is given here and reference ranges in industrial applications:

-0.074mm content accounts for 40% to 50%, 10mm: 15mm: 20mm = 1:1:3;

-0.074mm content accounted for 50% to 60%, 10mm: 15mm: 20mm = 1:2:2;

When the content of -0.074mm accounts for 60% to 70%, 10mm: 15mm: 20mm = 2:2:1;

-0.074mm content accounts for 70% to 80%, 10mm: 15mm: 20mm = 3:1:1;

3. The motor on the mill drives the agitator to rotate. When the agitator rotates, the edge line speed is 2.5-3.5m/s, pushing the grinding medium to grind the ore particles; adjust the ultrasonic frequency and sound pressure of the ultrasonic generating device on the cylinder wall Intensity, through the ultrasonic wave to break up the agglomerated particles, clean the slime and oxide film covering the dissociation surface, expand the microcracks between the valuable minerals and the gangue minerals in the ore particles, and make the single Body dissociation is more complete. The distance between the upper part of the cylinder and the discharge port of the grinding medium is 0.5-0.8mm, so as to prevent the grinding medium from being discharged together with the slurry, and entering the feed pump of the hydrocyclone to damage the equipment.

4. After grinding, the grinding products enter the buffer pool, and then the pump sends the slurry into the hydrocyclone. The pressure of the pump is determined according to the particle size of the overflow product, and the qualified grinding product enters the next overflow through the overflow. In the sorting operation, the unqualified grinding products return to the feed pipe of the mill through the underflow of the hydrocyclone, and enter the mill again for regrinding.

In the above step 1, the feeding speed needs to be determined according to the residence time of the ore particles in the grinding chamber, and the residence time of the ore in the grinding chamber is 3-5 minutes.

In the above step 1, the frequency of the ultrasonic wave is 40-60 Hz, and the sound pressure level is 100-130 dB.

Example 1

The raw material comes from the discharge of the first stage of the ball mill in Anshan Iron Ore Concentrator. The chemical composition analysis results of the ore are shown in Table 1. The grade of TFe in the iron ore is 47.20%, and the content of FeO is relatively high, indicating that it is magnetite. The main gangue mineral is quartz. , the main recovery element of this ore is iron.

Table 1 Analysis of chemical composition of raw ore

The pulp concentration is 55(±1)%, and the content of -0.074mm is 63(±1)%. The feeding pump is fed along the tangent from the bottom of the mill cylinder, and the feeding speed is 25g/(min·cm ² ) , the edge line speed of the stirrer rotation speed is 3.0m/s, the filling rate of the grinding medium is 75%, the proportion of the grinding medium is 10mm: 15mm: 20mm = 2:2:1, the height of the discharge port on the top of the grinding medium 0.6m, there are 5 horns from the bottom to the top, the angle between the horns in the same level is 180°, the frequency of the ultrasonic generators on both sides of the adjustment cylinder is 60Hz, and the sound pressure level is 100dB. Disperse the agglomerated particles by ultrasonic waves, clean the slime and oxide film covering the dissociation surface, expand the microcracks between the valuable minerals and gangue minerals in the ore particles, and decompose the monomers between the minerals more fully.

After grinding, the ore slurry enters the buffer pool through the discharge port, and is pumped into the hydrocyclone for classification, and the bottom flow returns to the mill for regrinding through gravity flow.

Compared with the grinding system without ultrasonic enhancement, the monomer dissociation ratio of each particle size of the grinding product in the overflow is shown in Table 2. The finer the grinding product is, the higher the monomer dissociation degree is, and the overall increase is 5 percentage points. above.

Use a magnetic separator to separate the overflow product under a field strength of 1000Oe. The grade of the magnetic iron concentrate is 66.78%, and the operating recovery rate is 94.22%.

Table 2 Comparison of monomer dissociation of overflow grinding products

Example 2

Method and embodiment 1, difference is: the ore sample used in this embodiment comes from a certain copper ore dressing plant in Jiangxi Province, belongs to complex refractory copper ore, the chemical composition analysis results of this ore are shown in Table 3, and the Cu content in the ore is 0.481%, the quartz content is 71.91%, the main recovered element in this ore is copper, and the main gangue mineral is quartz.

The material is taken from the discharge of a ball mill, the pulp concentration is 60(±1)%, and the content of -0.074mm is 65(±1)%. is 30g/(min·cm ² ), the edge linear velocity of the stirrer rotation speed is 3.2m/s, the filling rate of the grinding medium is 70%, and the proportion of the grinding medium is 10mm:15mm:20mm=1:2:2, The height of the discharge opening on the top of the grinding medium is 0.75m. There are 6 horns from bottom to top. The angle between the horns at the same level is 90°. Adjust the frequency of the ultrasonic generators on both sides of the cylinder. The frequency is 50Hz, the sound pressure level is 90dB, the agglomerated particles are broken up by ultrasonic waves, the slime and oxide film covering the dissociated surface are cleaned, and the microcracks between the valuable minerals and gangue minerals in the ore particles are enlarged , so that the monomer dissociation between minerals is more fully.

After grinding, the ore slurry enters the buffer pool through the discharge port, and is pumped into the hydrocyclone for classification. The content of -0.038mm in the overflow accounts for 90%, and the bottom flow returns to the mill for regrinding by gravity.

Compared with the grinding system without ultrasonic enhancement, the monomer dissociation ratio of each particle size of the grinding product in the overflow is shown in Table 4. The finer the grinding product is, the higher the monomer dissociation degree is, and the overall increase is about 8 percentage point.

The overflow product was subjected to primary flotation with an air-filled flotation machine, and the Cu grade of the copper rough concentrate obtained was 13.44, and the recovery rate was 81.12%.

Table 3 Analysis of chemical composition of raw ore

Table 4 Comparison of dissociation of overflow grinding products

Claims (10)

1. A high-efficiency grinding system for ultrasonically enhanced grinding, characterized in that it comprises a grinding device, an ultrasonic generating device and a classifying device; The ore grinding device includes a motor, a speed reducer, an agitator, a cylinder (406), a feeding port, a sieve plate and a discharge port; the cylinder (406) is fixed and vertical to the ground, and there is a stirring in the cylinder (406). device (405) and grinding medium (404), the bottom of the cylinder (406) is provided with a feeding pipe (403), and is fed through the stirring mill feed pump (201); the top of the cylinder (406) is provided with a discharge mouth (407), discharge port (407) and cylinder (406) joint is provided with sieve plate (408); Described ultrasonic generating device comprises ultrasonic generator (101), ultrasonic transducer (102) and horn (103), and described ultrasonic generator (101) is connected with several ultrasonic transducers (102), and ultrasonic transducer The energy device (102) is connected with the horn (103), and the horn (103) is embedded on the cylinder wall of the stirring mill, and the direction of the sound wave generated is perpendicular to the direction of the movement of the ore particles in the grinding chamber; The grading device includes an ore slurry buffer pool (3), a cyclone feed pump (202) and a hydrocyclone connected in sequence, the ore slurry buffer pool (3) is connected with the discharge port (407) of the grinding equipment, and the hydraulic The upper end of the hydrocyclone is connected with the next-level equipment, and the lower end of the hydrocyclone is connected with the feeding pipe (403). 2. The high-efficiency ore grinding system for ultrasonically enhanced ore grinding as claimed in claim 1, wherein the feeding speed of the ore grinding device is 20-40g/(min·cm ² ), that is, the material passing through the cylinder transverse The mass of material per square centimeter of cross-section. 3. The high-efficiency grinding system of ultrasonic enhanced grinding as claimed in claim 1, wherein the motor in the grinding device is connected with the reducer, the reducer is connected with the agitator, and the agitator is connected with the drum The body is on a central axis; the agitator (405) is a spiral type, a pin type or a disc type; the edge linear speed of the agitator (405) is 2.5-3.5m/s when rotating. 4. The high-efficiency grinding system of ultrasonic enhanced grinding as claimed in claim 1, characterized in that, in the cylinder (406), the stacked volume of the grinding media (404) accounts for 60% of the effective volume of the cylinder (406) ~80%, and the distance between the upper part of the cylinder (406) and the discharge port (407) of the grinding medium (404) is 0.5-0.8mm. 5. The high-efficiency grinding system of ultrasonic enhanced grinding as claimed in claim 1, characterized in that the ratio of the diameter of the grinding medium (404) in the cylinder (406) is determined according to the content of -0.074mm particles in the feed : When the content of -0.074mm particles accounts for 40% to 50%, the diameter ratio of grinding media is 10mm: 15mm: 20mm = 1:1:3; When the content of -0.074mm particles accounts for 50% to 60%, the diameter ratio of grinding media is 10mm: 15mm: 20mm = 1:2:2; When the content of -0.074mm particles accounts for 60% to 70%, the diameter ratio of grinding media is 10mm: 15mm: 20mm = 2:2:1; When the content of -0.074mm particles accounts for 70% to 80%, the diameter ratio of grinding media is 10mm: 15mm: 20mm = 3:1:1. 6. The high-efficiency ore grinding system of ultrasonic enhanced ore grinding as claimed in claim 1, characterized in that, in the cylinder (406), the ore particles are in the process of grinding, and the concentration of the ore slurry is 30%-60%; The sieve size of the plate (408) is smaller than the diameter of the grinding medium to prevent the grinding medium from flowing out with the slurry. 7. The high-efficiency grinding system for ultrasonically enhanced grinding as claimed in claim 1, characterized in that the vibration frequency of the ultrasonic generator (101) is 40-60 Hz, and the sound pressure level is 80-120 dB. 8. The high-efficiency grinding system for ultrasonically enhanced grinding as claimed in claim 1, characterized in that the included angles between the horns (103) at the same horizontal height on the cylinder (406) are 90°, 120° ° or 180°. 9. The high-efficiency grinding system of ultrasonic enhanced grinding as claimed in claim 1, characterized in that, the position where the horn (103) is embedded in the cylinder wall of the stirring mill is two stirrers (405) The 1/2 place between the rod pins is sealed with wear-resistant rubber around them so that they can be replaced after wear and tear. The direction in which the horn is installed is perpendicular to the direction in which the slurry flows. 10. The working method of the high-efficiency grinding system for ultrasonically enhanced grinding as claimed in any one of claims 1-9, wherein the material enters the grinding chamber along a tangent through the feed pipe (403) at the bottom of the grinding device , the agitator (405) rotates to drive the movement of the grinding medium (404) to produce a grinding effect, the ultrasonic generator (101) is connected with the ultrasonic transducer (102), and the ultrasonic transducer (102) converts electrical energy into vibration. The horn (103) transmits to the ore particles in the cylinder (406), and the direction of the ultrasonic wave generated by the ultrasonic wave is perpendicular to the flow direction of the particles in the grinding chamber; the material is dissociated and broken by ultrasonic waves while being ground, Then the material discharged from the discharge port (407) of the ore grinding device passes through the slurry buffer tank (3), and then is sent into the hydrocyclone by the cyclone feeding pump (202) for classification, and the qualified grinding products are produced by The overflow pipe (503) of the hydrocyclone enters the next operation, and the over-coarse grinding product enters the mill through the sand outlet (504) of the hydrocyclone for regrinding.