CN220803838U - Ore dressing system for improving grade of iron concentrate - Google Patents

Abstract

An beneficiation system for improving grade of fine iron powder, comprising: a pre-processing system and a post-processing system; the pretreatment system comprises: a dry magnetic separator, a No. 1 ore mill, a classifier, a No. 1 magnetic separator, a high-frequency screen, a No. 2 magnetic separator, a No. 2 ore mill, a No. 3 magnetic separator and a No. 1 grade elevator; the dry magnetic separator, the No. 1 ore mill, the classifier, the No. 1 magnetic separator and the high-frequency screen are sequentially communicated; the output end of the No. 3 magnetic separator is communicated with the input end of the No. 1 grade hoister; one input end of the cyclone is communicated with the output end of the No. 1 grade elevator; one of the output ends of the cyclone, the 3# ore mill, the 4# magnetic separator, the demagnetizer and one of the input ends of the cyclone are sequentially communicated; one of the output ends of the cyclone, the No. 1 refined magnetic separator, the No. 2 grade hoister and the filter are sequentially communicated. The utility model solves the problems that the grade of the iron concentrate processed by the existing mineral processing technology is low and the processing requirement is not met.

Description

Ore dressing system for improving grade of iron concentrate

Technical Field

The utility model relates to the technical field of ore dressing, in particular to an ore dressing system for improving the grade of iron concentrate.

Background

The iron concentrate is a main raw material for manufacturing pellets, the pellets are a main raw material for smelting steel in steel mills, and the iron concentrate is mineral powder processed by iron ores through crushing, grinding, mineral separation and other technicians, wherein the iron content directly influences the quality of finished pellets. The optimal iron content of the iron concentrate required for manufacturing the pellets is not less than 64%, the iron content of the iron concentrate obtained by processing most of iron separation plants in China is 58-62%, and the iron content of the iron concentrate has a great influence on the quality of the pellets. The existing iron ore raw stone is low in quality, the iron content in the ore is less than 60%, meanwhile, smelting steel needs to consume a lot of raw ore, and the environment ecology is damaged if the iron content is too low; therefore, the grade of the iron concentrate is very important, and the existing method for improving the grade of the iron concentrate is single:

1. For example, when the grinding fineness of iron ore cannot reach the standard, the selection of the iron concentrate is started, so that the grade of the iron concentrate is influenced, and the mineral monomer separation degree can influence the quality of the iron concentrate.

2. Many extracted iron concentrate contains a large amount of impurities, and the impurities have weak magnetism and cannot be removed, so that the grade of the iron concentrate is affected.

Disclosure of utility model

The utility model aims to provide a mineral separation system for improving the grade of iron concentrate, which is characterized in that a 3# magnetic separator and a 1# grade lifting machine are added in a pretreatment system, fine particles are sequentially subjected to magnetic separation in the 1# magnetic separator, the 2# magnetic separator and the 3# magnetic separator, the first magnetic separation is matched with high-frequency screen screening, the 2# concentrate after the second magnetic separation is transferred to a 2# ore mill, the 2# ore mill is returned to the high-frequency screen for continuous screening, and finally the 3# magnetic separator and the 1# grade lifting machine are used for pre-separating impurities and bad substances in minerals in advance, so that the impurities and the bad substances are separated from the concentrate.

To achieve the purpose, the utility model adopts the following technical scheme:

An beneficiation system for improving grade of fine iron powder, comprising: a pre-processing system and a post-processing system;

The pretreatment system includes: a dry magnetic separator, a No. 1 ore mill, a classifier, a No. 1 magnetic separator, a high-frequency screen, a No. 2 magnetic separator, a No. 2 ore mill, a No. 3 magnetic separator and a No. 1 grade elevator;

the dry magnetic separator, the No. 1 ore mill, the classifier, the No. 1 magnetic separator and the high-frequency screen are sequentially communicated; one output end of the high-frequency screen is communicated with the No. 2 magnetic separator, and the other output end of the high-frequency screen is communicated with the No. 3 magnetic separator; the No. 2 magnetic separator, the No. 2 ore mill and the high-frequency screen are sequentially communicated; the output end of the No. 3 magnetic separator is communicated with the input end of the No. 1 grade hoister;

The aftertreatment system includes: the device comprises a cyclone, a No. 3 ore mill, a No. 4 magnetic separator, a demagnetizing machine, a No. 1 fine magnetic separator, a No. 2 grade hoister and a filter;

One input end of the cyclone is communicated with the output end of the grade 1 lifting machine; one of the output ends of the cyclone, the 3# ore mill, the 4# magnetic separator, the demagnetizer and one of the input ends of the cyclone are sequentially communicated;

one of the output ends of the cyclone, the No. 1 refined magnetic separator, the No. 2 grade hoister and the filter are sequentially communicated.

Preferably, one of the output ends of the classifier is communicated with the input end of the No. 1 ore mill.

Preferably, the method further comprises: a tail material feeding pipe;

the input end of the tailing charging pipe is communicated with at least one of the No. 2 magnetic separator, the No. 3 magnetic separator, the No. 4 magnetic separator, the No. 1 magnetic separator, the No. 2 grade hoister and the filter, and the output end of the tailing charging pipe is communicated with the input end of the classifier.

More preferably, the method further comprises: a tailings pond;

And the input end of the tailing pond is communicated with one of the output ends of the No. 1 magnetic separator and/or one of the output ends of the No. 1 grade hoister.

Preferably, the high-frequency screen sequentially comprises, from top to bottom: a first screen, a second screen, and a third screen;

The mesh number of the first screen mesh and the second screen mesh is 90-110 mesh, and the mesh number of the third screen mesh is 120 mesh.

Preferably, the filter is a disc filter.

Preferably, the method further comprises: a sand pump pool;

The input end of the sand pump pool is communicated with the output end of the grade 1 lifting machine; the output end of the sand pump pool is communicated with one of the input ends of the cyclone.

More preferably, the sand pump pool is provided with a slurry pump.

Compared with the prior art, one of the technical schemes has the following beneficial effects:

According to the ore dressing system for improving the grade of the iron concentrate, a 3# magnetic separator and a 1# grade lifting machine are added in a pretreatment system, fine particles are sequentially subjected to magnetic separation in the 1# magnetic separator, the 2# magnetic separator and the 3# magnetic separator, the first magnetic separation is matched with high-frequency screen screening, the 2# concentrate after the second magnetic separation is transferred to a 2# ore grinding machine, the 2# ore grinding machine returns to the high-frequency screen for continuous screening, and finally the 3# magnetic separator and the 1# grade lifting machine are used for pre-selecting impurities and bad substances in minerals in advance, so that the impurities and the bad substances are separated from the concentrate, the fine magnetic separation of a subsequent post-treatment system is facilitated, the screening, magnetic separation, ore grinding, demagnetizing and fine magnetic separation efficiency of the post-treatment system are further improved, and the grade of the iron concentrate is further improved, and the problem that the grade of the iron concentrate after the existing ore dressing process is low and processing requirements are not met is solved.

Drawings

FIG. 1 is a schematic diagram of one embodiment of a beneficiation system to upgrade fine iron ore;

FIG. 2 is a schematic flow diagram of one embodiment of a beneficiation process to upgrade fine iron ore;

fig. 3 is a schematic view of the structure of one embodiment of the high frequency screen.

Wherein:

Dry separator 11, no. 1 mill 12, classifier 13, no. 1 magnetic separator 14, high frequency screen 15, no. 2 magnetic separator 16, no. 2 mill 17, no. 3 magnetic separator 18, no. 1 grade elevator 19;

A sand pump pool 20; cyclone 21, no. 3 mill 22, no. 4 magnetic separator 23, demagnetizer 24, no. 1 magnetic separator 25, no. 2 magnetic separator 26, no. 2 grade lifter 27, and filter 28. A tail material feeding pipe 3; a tailings pond 4;

a first screen 151, a second screen 152, a third screen 153; slurry pump 201.

Detailed Description

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the utility model.

In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the drawings, are merely for convenience in describing the present utility model and simplify the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model. Furthermore, features defining "first", "second" may include one or more such features, either explicitly or implicitly, for distinguishing between the descriptive features, and not sequentially, and not lightly. In the description of the present utility model, unless otherwise indicated, the meaning of "plurality" is two or more.

1-3, A beneficiation system to upgrade fine iron powder, comprising: a pre-processing system and a post-processing system;

The pretreatment system includes: dry magnetic separator 11, no. 1 mill 12, classifier 13, no. 1 magnetic separator 14, high frequency screen 15, no. 2 magnetic separator 16, no. 2 mill 17, no. 3 magnetic separator 18, and No. 1 grade elevator 19;

The dry magnetic separator 11, the No. 1 ore mill 12, the classifier 13, the No. 1 magnetic separator 14 and the high-frequency screen 15 are sequentially communicated; one output end of the high-frequency screen 15 is communicated with the No. 2 magnetic separator 16, and the other output end of the high-frequency screen is communicated with the No. 3 magnetic separator 18; the No. 2 magnetic separator 16, the No. 2 ore mill 17 and the high-frequency screen 15 are sequentially communicated; the output end of the No. 3 magnetic separator 18 is communicated with the input end of the No. 1 grade lifting machine 19;

The aftertreatment system includes: cyclone 21, no. 3 mill 22, no. 4 magnetic separator 23, demagnetizer 24, no. 1 magnetic separator 25, no. 2 magnetic separator 26, no. 2 grade lifter 27 and filter 28;

One of the input ends of the cyclone 21 is communicated with the output end of the grade 1 lifting machine 19; one of the output ends of the cyclone 21, the No. 3 ore mill 22, the No. 4 magnetic separator 23, the demagnetizer 24 and one of the input ends of the cyclone 21 are sequentially communicated;

one output end of the cyclone 21, the No. 1 refined magnetic separator 25, the No. 2 refined magnetic separator 26, the No. 2 grade lifting machine 27 and the filter 28 are sequentially communicated.

According to the ore dressing system for improving the grade of the iron concentrate, a 3# magnetic separator 18 and a 1# grade lifting machine 19 are added in a pretreatment system, fine particles are sequentially subjected to magnetic separation in the 1# magnetic separator 14, the 2# magnetic separator 16 and the 3# magnetic separator 18, the first magnetic separation is matched with the high-frequency screen 15 for screening, the 2# concentrate after the second magnetic separation is transferred to the 2# ore grinding machine 17, the 2# ore grinding machine 17 is returned to the high-frequency screen 15 for continuous screening, and finally impurities and bad substances in the minerals are pre-selected in advance through the 3# magnetic separator 18 and the 1# grade lifting machine 19, so that the impurities and the bad substances are separated from the concentrate, the fine magnetic separation of a follow-up treatment system is facilitated, the screening, magnetic separation, ore grinding, demagnetizing and fine magnetic separation efficiency of the follow-up treatment system are further improved, and the grade of the iron concentrate is further improved, and the problem that the grade of the iron concentrate after the existing ore dressing process is low is not met.

In the scheme, the magnetic separator is used for separating magnetic minerals from non-magnetic minerals through a strong magnetic field. The grade lifting machine is used for separating lean intergrowth from high-grade concentrate by the action of magnetic force, centrifugal force, gravity and buoyancy.

Preferably, one of the outputs of the classifier 13 is in communication with the input of the # 1 mill 12.

The classifier 13 separates fine particles and coarse particles, and the coarse particles can be returned to the No. 1 ore mill 12 again to perform coarse-fine separation again, so that the utilization rate of minerals is improved.

Preferably, the method further comprises: a tail material feeding pipe 3;

The input end of the tailing feeding pipe 3 is communicated with at least one of the No. 2 magnetic separator 16, the No. 3 magnetic separator 18, the No. 4 magnetic separator 23, the No. 1 magnetic separator 25, the No. 2 magnetic separator 26, the No. 2 grade lifting machine 27 and the filter 28, and the output end of the tailing feeding pipe 3 is communicated with the input end of the classifier 13.

Tailings separated by the No. 2 magnetic separator 16, the No. 3 magnetic separator 18, the No. 4 magnetic separator 23, the No. 1 fine magnetic separator 25, the No. 2 fine magnetic separator 26, the No. 2 grade lifting machine 27 and the filter 28 can be recycled and directly added into a pretreatment system, so that residual iron in the tailings is fully recovered; when the tailings are reused in the scheme, the process parameters according to the scheme and the screening association degree based on the adjacent devices are high, the tailings of the part cannot cause the grade reduction of the iron concentrate, impurities in the system can be finally concentrated to the tailings dry discharge site or the tailings pond 4, and iron in the tailings can be fully recovered.

More preferably, the method further comprises: a tailings pond 4;

The input end of the tailing pond 4 is communicated with one output end of the No. 1 magnetic separator 14 and/or one output end of the No. 1 grade lifting machine 19.

The tailing pond 4 can be used for collecting the 1# tailings after the magnetic separation of the 1# magnetic separator 14 and also can be used for collecting the 8# tailings of the 1# grade lifting machine 19, so that the part which cannot be reused in the mineral separation system is recycled, and the part is discharged out of the system, so that the tailings are prevented from remaining in the system to influence the grade of the iron concentrate.

Preferably, the high frequency screen 15 comprises, in order from top to bottom: a first screen 151, a second screen 152, and a third screen 153;

The first screen 151 and the second screen 152 have a mesh number of 90 to 110, and the third screen 153 has a mesh number of 120.

The high-frequency screen 15 is provided with a first screen 151, a second screen 152 and a third screen 153, after the 1# concentrate passes through the first screen 151, the second screen 152 and the third screen 153 in sequence, the 1# concentrate can be fully screened by arranging two sections of screens with 90-110 meshes, so that the 1# concentrate passes through 120 meshes, and 120 meshes of particles can be reserved on the third screen 153; according to the distribution of the screens, the proportion of minerals with more than 120 meshes in the upper coarse particles of the third screen 153 is 40-50%, so that the process requirements of a subsequent post-treatment system are met.

Preferably, the filter 28 is a disc filter 28.

The disc filter 28 mainly comprises a tank body, a main shaft, a filter disc, a distributing valve, a stripping device, a flushing device, a net washing device, a transmission device, a discharging device and the like, and is a beneficiation process for recycling and preparing 6# concentrate by taking vacuum as filtering power, is convenient to use and maintain, and is very suitable for improving the grade of the iron concentrate.

Preferably, the method further comprises: a sand pump pool 20;

The input end of the sand pump pool 20 is communicated with the output end of the grade 1 lifting machine 19; the output end of the sand pump tank 20 is communicated with one of the input ends of the cyclone 21.

The sand pump pool 20 can be used for storing the 8# concentrate processed by the pretreatment system, and can be used as a transfer mechanism between the pretreatment system and the post-treatment system, and the system can convey 8# concentrate with different quantities to a cyclone 21 of the post-treatment system according to the requirements, so that the storage capacity of the mineral separation system is improved; meanwhile, the sand pump pool 20 can provide a buffer space between the pretreatment system and the post-treatment system, so that the fault tolerance of pretreatment of the pretreatment system can be improved, and ores produced by the failure of the pretreatment system can be collected from the sand pump pool 20 and discharged outside the system.

Preferably, the sand pump tank 20 is provided with a slurry pump 201.

The sand pump pool 20 is provided with a slurry pump 201, and 8# concentrate in the sand pump pool 20 is conveyed to the cyclone 21 through the slurry pump 201; the 8# concentrate can be subjected to centrifugal sedimentation by the cyclone 21, and ore pulp particles of the 8# concentrate can be separated by particle size.

An ore dressing process for improving the grade of iron concentrate comprises the following steps:

S1, crushing raw iron ore to a granularity less than or equal to 1.0cm through a crusher, and conveying the iron ore to a dry magnetic separator 11; after magnetic separation by a dry magnetic separator 11 at a magnetic field strength of 0.55-0.60T, feeding the dry separated 0# concentrate into a 1# ore grinding machine 12;

In the step, the 0# concentrate after dry separation is sent to a 1# ore grinding machine 12; and discharging the dry separation No. 0 tailings, and conveying the tailings to a dry discharge field through a conveying belt.

S2, grinding the 0# concentrate by a 1# ore grinding machine 12 until the concentration of the ore pulp is 73-80% and the fineness of the ore pulp is 200 meshes and is 40-45%, and enabling the ore pulp after grinding to flow into a classifier 13 for coarse and fine particle differentiation; fine particles below 200 meshes flow into the No. 1 magnetic separator 14 through a conveying pipeline;

Step S3, carrying out magnetic separation on fine particles by a No. 1 magnetic separator 14 at a magnetic field intensity of 0.3-0.4T, discharging the 1# tailings after magnetic separation, and enabling the 1# concentrate after magnetic separation to flow into a high-frequency screen 15; screening by a high-frequency screen 15, feeding coarse particles on the screen into a No. 2 magnetic separator 16, magnetically separating under the magnetic field intensity of 0.3-0.4T, and feeding the magnetically separated No. 2 concentrate into a No. 2 ore mill 17 for fine grinding; grinding the No. 2 concentrate to 70-80% by the No. 2 ore grinding machine 17, wherein the fineness is 30-40% by 200 meshes, and returning the ore pulp to the high-frequency screen 15 for continuous screening; the undersize particles of the high-frequency screen 15 enter a No. 3 magnetic separator 18, the No. 7 tailings magnetically separated by the No. 3 magnetic separator 18 are returned to the classifier 13 to be continuously screened and magnetically separated, and the magnetically separated No. 7 concentrate enters a No. 1 grade lifting machine 19;

S4, purifying the No. 7 concentrate by using a No. 1 grade lifter 19 at a magnetic field intensity of 0.55-0.6T, discharging 8# tailings in the ore pulp, and conveying the purified No. 8 concentrate to a cyclone 21, wherein the cyclone 21 separates the ore pulp particles into coarse and fine;

A sand pump pool 20 for storing 8# concentrate is arranged between the 1# grade lifting machine 19 and the cyclone 21; the sand pump pool can also be provided with a slurry pump 201, and 8# concentrate in the sand pump pool is conveyed to the cyclone 21 through the slurry pump 201; the 8# concentrate can be subjected to centrifugal sedimentation by the cyclone 21, and ore pulp particles of the 8# concentrate can be separated by particle size.

S5, separating coarse particles, continuously grinding the coarse particles in a No. 3 ore grinding machine 22 until the concentration is 66-73% and the fineness is 325 meshes 65-70%, conveying ore pulp to a No. 4 magnetic separator 23, and returning the 9# ore concentrate subjected to magnetic separation with the magnetic field strength of 0.3-0.4T to a cyclone 21 for continuous coarse-fine separation after passing through a demagnetizer 24;

The step is to purify the ore concentrate to 9# by using a No. 4 magnetic separator 23, and then break up particles in ore pulp to separate inclusion substances from magnetic substances, so that the ore pulp is easy to filter by a subsequent fine magnetic separator.

S6, fine particles screened by the cyclone 21 enter a No. 1 fine magnetic separator 25 for magnetic separation, the magnetic field strength is 0.15-0.25T, and the 3# concentrate after magnetic separation enters a No. 2 fine magnetic separator 26;

step S7, carrying out magnetic separation on the 3# concentrate by a 2# concentrate magnetic separator 26, wherein the magnetic field intensity is 0.15-0.25T, and the 4# concentrate after magnetic separation enters a 2# grade lifting machine 27 and is purified again at the magnetic field intensity of 0.55-0.6T;

S8, separating and purifying the 5# concentrate in a 2# grade lifting machine 27, and feeding the 5# concentrate into a filter 28; the filter 28 filters the water contained in the No. 5 concentrate, and the filtered No. 6 concentrate is the high-grade iron concentrate.

The moisture of the No. 6 concentrate can be adjusted according to the needs, and the moisture content is preferably controlled to be 8-9%.

According to the scheme, the 3# magnetic separator 18 and the 1# grade lifting machine 19 are added in the pretreatment system, particularly fine particles in the step S3 are sequentially subjected to magnetic separation in the 1# magnetic separator 14, the 2# magnetic separator 16 and the 3# magnetic separator 18, the first magnetic separation is matched with the high-frequency screen 15 for screening, the 2# concentrate after the second magnetic separation is transferred to the 2# ore grinding machine 17, the 2# ore grinding machine 17 returns to the high-frequency screen 15 for continuous screening, and finally impurities and bad substances in minerals are pre-selected in advance through the 3# magnetic separator 18 and the 1# grade lifting machine 19, so that the impurities and the bad substances are separated from the concentrate, the fine magnetic separation of a subsequent treatment system is facilitated, the screening, magnetic separation, ore grinding, demagnetizing and fine magnetic separation efficiency of the aftertreatment system are further improved, and the grade of the iron concentrate is further improved, and the problems that the grade of the iron concentrate treated by the existing ore concentrate concentrating process is low and the processing requirements are not met are solved.

In the step S3, the frequency of the high-frequency screen 15 is 70-90Hz, the vibration intensity is 8-10g, and the amplitude is 2-3mm. In the scheme, the parameters of the high-frequency screen 15 are preferably controlled to be 70-90Hz, the vibration intensity is 8-10g, and the amplitude is 2-3mm, in the embodiment, the frequency and the vibration intensity of the high-frequency screen 15 are higher than those of a common mechanical vibration screen, the high-frequency screen 15 is used for destroying the surface tension of ore pulp and the adhesion force among particles through high-frequency vibration, the agglomeration force among fine-grained materials can be reduced, the loosening and layering of the materials are rapidly realized, and the probability of fine-grained screening is increased. And through the outstanding with the sieve surface of high frequency screen 15 vibration energy increase, reduce the jam condition of sieve mesh, increase the probability of passing through the sieve for high frequency screen 15 not only has more apparent hierarchical dehydration effect, but also can play the effect of desliming and ash reduction to a certain extent for ordinary mechanical vibrating screen.

The unit of vibration intensity in this step is g, i.e., acceleration.

In the step S3, the high frequency screen 15 sequentially includes: a first screen 151, a second screen 152, and a third screen 153; the first screen 151 and the second screen 152 have a mesh number of 90 to 110, and the third screen 153 has a mesh number of 120. The high-frequency screen 15 is provided with a first screen 151, a second screen 152 and a third screen 153, after the 1# concentrate passes through the first screen 151, the second screen 152 and the third screen 153 in sequence, the 1# concentrate can be fully screened by arranging two sections of screens with 90-110 meshes, so that the 1# concentrate passes through 120 meshes, and 120 meshes of particles can be reserved on the third screen 153; according to the distribution of the screens, the proportion of minerals with more than 120 meshes in the upper coarse particles of the third screen 153 is 40-50%, so that the process requirements are met.

In the step S5, the cyclone 21 continuously performs coarse-fine separation on the 9# concentrate until the-200 mesh ratio is 80-90%, and the +200 mesh ratio is 10-20%. -200 mesh means below 200 mesh, +200 mesh means above 200 mesh; in the step S5, minerals with more than 200 meshes and minerals with less than 200 meshes can be distinguished, the scheme is characterized in that coarse and fine separation is carried out continuously according to the cyclone 21, the mesh number of particles is controlled to be 200 meshes, the proportion of the particles with the mesh number of minus 200 meshes is controlled to be 80-90 percent, the particles enter the No. 1 fine magnetic separator 25, on one hand, the subsequent magnetic separation can be conveniently carried out on the No. 1 fine magnetic separator 25, on the other hand, the No. 9 concentrate can be fully magnetically separated on the No. 1 fine magnetic separator 25 due to the fact that the No. 9 concentrate passes through the demagnetizer 24, impurities are separated, and then high-grade iron fine powder can be obtained after the subsequent No. 2 grade lifting machine 27 is purified.

In the step S2, coarse particles of 200 mesh or more are returned to the # 1 grinding machine 12 to continue grinding. In the step S2, over 200 meshes are coarse particles, and the magnetic separation efficiency is low when the coarse particles enter the No. 1 magnetic separator 14, so that the coarse particles can be returned to the No. 1 magnetic separator 12 again, on one hand, the magnetic separation effect of the No. 1 magnetic separator 14 can be improved, and on the other hand, the mesh number of the coarse particles is finally below 200 meshes, so that the magnetic separation is facilitated, and the ore pulp in the step S2 can be finally ground into the specification conforming to the high-frequency screen 15.

In the step S3, after being screened by a high-frequency screen 15, coarse particles on the screen enter a No. 2 magnetic separator 16, magnetic separation is carried out under the magnetic field intensity of 0.3-0.4T, and the tailings No. 2 after magnetic separation return to the classifier 13. Part of minerals in the No. 2 tailings can be returned to the classifier 13 again for coarse and fine particle distinction, so that the No. 2 tailings are fully utilized, and the grade of the iron concentrate is improved.

In the step S5, the ore pulp is conveyed to a No. 4 magnetic separator 23, and the 9# tailings after magnetic separation with the magnetic field intensity of 0.3-0.4T are returned to the classifier 13 for continuous screening;

And/or in the step S6, fine particles screened by the cyclone 21 enter a No. 1 fine magnetic separator 25 for magnetic separation, and the tailings No. 3 after magnetic separation return to the classifier 13;

And/or in the step S7, the No. 2 concentrate is subjected to magnetic separation by a No. 2 fine magnetic separator 26, and the 4 tailings after the magnetic separation are returned to the classifier 13;

And/or in the step S8, the No. 5 tailings separated by the No. 2 grade lifting machine 27 are returned to the classifier 13, the water contained in the No. 5 concentrate is filtered by the filter 28, and the filtered No. 6 tailings water is returned to the classifier 13 for circular screening.

For the steps S5-S8, the separated tailings can be recycled and directly added into a front-end device, so that the residual iron in the tailings is fully recovered; when the tailings are reused in the scheme, the process parameters according to the scheme and the screening association degree based on the adjacent devices are high, the tailings of the part cannot cause the grade reduction of the iron concentrate, impurities in the system can be finally concentrated to the tailings dry discharge site or the tailings pond 4, and iron in the tailings can be fully recovered.

Example A1:

an ore dressing process for improving the grade of iron concentrate comprises the following steps:

S1, crushing a raw iron ore road paved with stone by a crusher until the granularity is 1.0cm, and conveying the iron ore to a dry magnetic separator; after magnetic separation by a dry magnetic separator at the magnetic field intensity of 0.60T, feeding the dry-separated 0# concentrate into a 1# ore grinding machine, and feeding the dry-separated 0# tailings into a tailings dry discharge site;

S2, grinding the 0# concentrate by a 1# ore grinding machine, grinding the ore pulp to 80% and the fineness of 200 meshes to 40%, and enabling the ore pulp to flow into a classifier for coarse and fine particle differentiation after grinding; fine particles below 200 meshes flow into a No. 1 magnetic separator through a conveying pipeline, and coarse particles above 200 meshes return to a No. 1 ore mill to be continuously ground;

S3, carrying out magnetic separation on fine particles at a magnetic field intensity of 0.4T by a No. 1 magnetic separator, discharging the No. 1 tailings after magnetic separation, and enabling the No. 1 concentrate after magnetic separation to flow into a high-frequency sieve, wherein the frequency of the high-frequency sieve is 80Hz, the vibration intensity is 9g, the amplitude is 2mm, the high-frequency sieve is divided into 3 sections, the first section of screen mesh and the second section of screen mesh are 100 meshes, and the third section of screen mesh is 120 meshes; screening by a high-frequency screen, enabling coarse particles on the screen to enter a No. 2 magnetic separator, magnetically separating the coarse particles under the magnetic field strength of 0.4T, and enabling the 2 concentrate subjected to magnetic separation to enter a No. 2 ore mill for fine grinding; grinding the No. 2 concentrate to 70% concentration and 40% fineness by 200 mesh by a No. 2 ore grinding machine, and returning the ore pulp to a high-frequency screen for continuous screening; fine particles under the high-frequency sieve enter a No. 3 magnetic separator, the 7# tailings after magnetic separation return to a classifier to continue sieving and magnetic separation, and the 7# concentrate after magnetic separation enters a No. 1 grade lifter; feeding the coarse particles on the screen into a No. 2 magnetic separator, magnetically separating the coarse particles under the magnetic field strength of 0.4T, and returning the magnetically separated No. 2 tailings to the classifier;

S4, purifying the No. 7 concentrate by using a No. 1 grade lifter at the magnetic field intensity of 0.55T, discharging 8# tailings in the ore pulp, and conveying the purified No. 8 concentrate to a cyclone, wherein the cyclone separates the ore pulp particles;

S5, separating coarse particles, continuously grinding the coarse particles in a No. 3 ore grinding machine until the concentration is 70%, the fineness is 325 meshes of 70%, conveying ore pulp to a No. 4 magnetic separator, and returning the 9 concentrate subjected to magnetic separation with the magnetic field strength of 0.3T to a cyclone for continuous coarse and fine separation until the concentration is 90% in terms of 200 meshes and 10% in terms of 200 meshes in terms of +200 meshes; returning the 9# tailings subjected to magnetic separation to a classifier for continuous screening;

S6, fine particles screened by the cyclone enter a No. 1 fine magnetic separator for magnetic separation, the magnetic field strength is 0.18T, the 3# concentrate after magnetic separation enters a No. 2 fine magnetic separator, and the 3# tailings after magnetic separation return to the classifier;

Step S7, carrying out magnetic separation on the 3# concentrate by a 2# fine magnetic separator, wherein the magnetic field intensity is 0.18T, enabling the 4# concentrate after magnetic separation to enter a 2# grade lifting machine, purifying again at the magnetic field intensity of 0.55T, and returning the 4# tailings after magnetic separation to a classifier;

S8, separating and purifying the 5# concentrate by a 2# grade lifting machine, feeding the separated 5# concentrate into a filter, and returning the separated 5# tailings to a classifier; filtering water contained in the No. 5 concentrate by a filter, wherein the filtered No. 6 concentrate is the high-grade iron fine powder.

Example A2:

an ore dressing process for improving the grade of iron concentrate comprises the following steps:

S1, crushing a raw iron ore road paved with stone by a crusher to a granularity of 0.8cm, and conveying the iron ore to a dry magnetic separator; after magnetic separation by a dry magnetic separator at the magnetic field strength of 0.55T, feeding the dry-separated 0# concentrate into a 1# ore grinding machine, and feeding the dry-separated 0# tailings into a tailings dry discharge site;

S2, grinding the 0# concentrate by a 1# ore grinding machine, grinding the ore pulp to 73% and the fineness of 200 meshes to 45%, and enabling the ore pulp to flow into a classifier for coarse and fine particle differentiation after grinding; fine particles below 200 meshes flow into a No. 1 magnetic separator through a conveying pipeline, and coarse particles above 200 meshes return to a No. 1 ore mill to be continuously ground;

S3, carrying out magnetic separation on fine particles at a magnetic field intensity of 0.3T by a No. 1 magnetic separator, discharging the No. 1 tailings after magnetic separation, and enabling the No. 1 concentrate after magnetic separation to flow into a high-frequency sieve, wherein the frequency of the high-frequency sieve is 70Hz, the vibration intensity is 8g, the amplitude is 2mm, the high-frequency sieve is divided into 3 sections, the first section of screen mesh and the second section of screen mesh are 100 meshes, and the third section of screen mesh is 120 meshes; screening by a high-frequency screen, enabling coarse particles on the screen to enter a No. 2 magnetic separator, magnetically separating the coarse particles under the magnetic field strength of 0.3T, and enabling the 2 concentrate subjected to magnetic separation to enter a No. 2 ore mill for fine grinding; grinding the No. 2 concentrate to 70% concentration and 30% fineness by 200 mesh by a No. 2 ore grinding machine, and returning the ore pulp to a high-frequency screen for continuous screening; fine particles under the high-frequency sieve enter a No. 3 magnetic separator, the 7# tailings after magnetic separation return to a classifier to continue sieving and magnetic separation, and the 7# concentrate after magnetic separation enters a No. 1 grade lifter; feeding the coarse particles on the screen into a No. 2 magnetic separator, magnetically separating the coarse particles under the magnetic field strength of 0.3T, and returning the magnetically separated No. 2 tailings to the classifier;

S4, purifying the No. 7 concentrate by using a No. 1 grade lifter at the magnetic field intensity of 0.6T, discharging 8# tailings in the ore pulp, and conveying the purified No. 8 concentrate to a cyclone, wherein the cyclone separates the ore pulp particles;

S5, separating coarse particles, continuously grinding the coarse particles in a No. 3 ore grinding machine until the concentration is 66%, the fineness is 325 meshes of 70%, conveying ore pulp to a No. 4 magnetic separator, and returning the 9# ore concentrate subjected to magnetic separation with the magnetic field strength of 0.4T to a cyclone for continuous coarse and fine separation until the concentration is 80% of-200 meshes and the concentration is 20% of +200 meshes; returning the 9# tailings subjected to magnetic separation to a classifier for continuous screening;

s6, fine particles screened by the cyclone enter a No. 1 fine magnetic separator for magnetic separation, the magnetic field strength is 0.15T, the 3# concentrate after magnetic separation enters a No. 2 fine magnetic separator, and the 3# tailings after magnetic separation return to the classifier;

Step S7, carrying out magnetic separation on the 3# concentrate by a 2# fine magnetic separator, wherein the magnetic field intensity is 0.15T, enabling the 4# concentrate after magnetic separation to enter a 2# grade lifting machine, purifying again at the magnetic field intensity of 0.6T, and returning the 4# tailings after magnetic separation to a classifier;

S8, separating and purifying the 5# concentrate by a 2# grade lifting machine, feeding the separated 5# concentrate into a filter, and returning the separated 5# tailings to a classifier; filtering water contained in the No. 5 concentrate by a filter, wherein the filtered No. 6 concentrate is the high-grade iron fine powder.

Example A3:

an ore dressing process for improving the grade of iron concentrate comprises the following steps:

S1, crushing a raw iron ore road paved with stone by a crusher to a granularity of 0.9cm, and conveying the iron ore to a dry magnetic separator; after magnetic separation by a dry magnetic separator at the magnetic field intensity of 0.60T, feeding the dry-separated 0# concentrate into a 1# ore grinding machine, and feeding the dry-separated 0# tailings into a tailings dry discharge site;

S2, grinding the 0# concentrate by a 1# ore grinding machine, grinding the ore pulp to 75% and the fineness of 200 meshes to 40%, and enabling the ore pulp to flow into a classifier for coarse and fine particle differentiation after grinding; fine particles below 200 meshes flow into a No. 1 magnetic separator through a conveying pipeline, and coarse particles above 200 meshes return to a No. 1 ore mill to be continuously ground;

S3, carrying out magnetic separation on fine particles at a magnetic field intensity of 0.3T by a No. 1 magnetic separator, discharging the No. 1 tailings after magnetic separation, and enabling the No. 1 concentrate after magnetic separation to flow into a high-frequency sieve, wherein the frequency of the high-frequency sieve is 75Hz, the vibration intensity is 9g, the amplitude is 2mm, the high-frequency sieve is divided into 3 sections, the first section of screen is 100 meshes, the second section of screen is 110 meshes, and the third section of screen is 120 meshes; screening by a high-frequency screen, enabling coarse particles on the screen to enter a No. 2 magnetic separator, magnetically separating the coarse particles under the magnetic field strength of 0.3T, and enabling the 2 concentrate subjected to magnetic separation to enter a No. 2 ore mill for fine grinding; grinding the No. 2 concentrate to 70% concentration and 30% fineness by 200 mesh by a No. 2 ore grinding machine, and returning the ore pulp to a high-frequency screen for continuous screening; fine particles under the high-frequency sieve enter a No. 3 magnetic separator, the 7# tailings after magnetic separation return to a classifier to continue sieving and magnetic separation, and the 7# concentrate after magnetic separation enters a No. 1 grade lifter; feeding the coarse particles on the screen into a No. 2 magnetic separator, magnetically separating the coarse particles under the magnetic field strength of 0.3T, and returning the magnetically separated No. 2 tailings to the classifier;

S4, purifying the No. 7 concentrate by using a No. 1 grade lifter at the magnetic field intensity of 0.6T, discharging 8# tailings in the ore pulp, and conveying the purified No. 8 concentrate to a cyclone, wherein the cyclone separates the ore pulp particles;

S5, separating coarse particles, continuously grinding the coarse particles in a No. 3 ore grinding machine until the concentration is 70%, the fineness is 325 meshes of 70%, conveying ore pulp to a No. 4 magnetic separator, and returning the 9 concentrate subjected to magnetic separation with the magnetic field strength of 0.3T to a cyclone for continuous coarse and fine separation until the concentration is 80% of-200 meshes and the concentration is 20% of +200 meshes; returning the 9# tailings subjected to magnetic separation to a classifier for continuous screening;

S6, fine particles screened by the cyclone enter a No. 1 fine magnetic separator for magnetic separation, the magnetic field strength is 0.25T, the 3# concentrate after magnetic separation enters a No. 2 fine magnetic separator, and the 3# tailings after magnetic separation return to the classifier;

Step S7, carrying out magnetic separation on the 3# concentrate by a 2# fine magnetic separator, wherein the magnetic field intensity is 0.25T, enabling the 4# concentrate after magnetic separation to enter a 2# grade lifting machine, purifying again at the magnetic field intensity of 0.6T, and returning the 4# tailings after magnetic separation to a classifier;

S8, separating and purifying the 5# concentrate by a 2# grade lifting machine, feeding the separated 5# concentrate into a filter, and returning the separated 5# tailings to a classifier; filtering water contained in the No. 5 concentrate by a filter, wherein the filtered No. 6 concentrate is the high-grade iron fine powder.

The performance test was conducted on examples A1 to A3 to test the iron content of the fine iron powder, and the results are shown in table 1.

TABLE 1 iron content of example A

Project	Example A1	Example A2	Example A3
				Iron content of iron concentrate (%)	68	70	66

While embodiments of the present utility model have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the utility model, the scope of which is defined by the claims and their equivalents.

Claims (8)

1. An ore dressing system for improving the grade of fine iron powder, which is characterized by comprising: a pre-processing system and a post-processing system;

The pretreatment system includes: a dry magnetic separator, a No. 1 ore mill, a classifier, a No. 1 magnetic separator, a high-frequency screen, a No. 2 magnetic separator, a No. 2 ore mill, a No. 3 magnetic separator and a No. 1 grade elevator;

the dry magnetic separator, the No. 1 ore mill, the classifier, the No. 1 magnetic separator and the high-frequency screen are sequentially communicated; one output end of the high-frequency screen is communicated with the No. 2 magnetic separator, and the other output end of the high-frequency screen is communicated with the No. 3 magnetic separator; the No. 2 magnetic separator, the No. 2 ore mill and the high-frequency screen are sequentially communicated; the output end of the No. 3 magnetic separator is communicated with the input end of the No. 1 grade hoister;

The aftertreatment system includes: the device comprises a cyclone, a No. 3 ore mill, a No. 4 magnetic separator, a demagnetizing machine, a No. 1 fine magnetic separator, a No. 2 grade hoister and a filter;

One input end of the cyclone is communicated with the output end of the grade 1 lifting machine; one of the output ends of the cyclone, the 3# ore mill, the 4# magnetic separator, the demagnetizer and one of the input ends of the cyclone are sequentially communicated;

one of the output ends of the cyclone, the No. 1 refined magnetic separator, the No. 2 grade hoister and the filter are sequentially communicated.

2. A beneficiation system to upgrade fine iron ore according to claim 1, wherein one of the output ends of the classifier is connected to the input end of the # 1 mill.

3. A beneficiation system to upgrade fine iron powder according to claim 1, further comprising: a tail material feeding pipe;

the input end of the tailing charging pipe is communicated with at least one of the No. 2 magnetic separator, the No. 3 magnetic separator, the No. 4 magnetic separator, the No. 1 magnetic separator, the No. 2 grade hoister and the filter, and the output end of the tailing charging pipe is communicated with the input end of the classifier.

4. A beneficiation system to upgrade fine iron powder according to claim 3, further comprising: a tailings pond;

And the input end of the tailing pond is communicated with one of the output ends of the No. 1 magnetic separator and/or one of the output ends of the No. 1 grade hoister.

5. The beneficiation system for improving the grade of the fine iron powder according to claim 1, wherein the high-frequency screen comprises, in order from top to bottom: a first screen, a second screen, and a third screen;

The mesh number of the first screen mesh and the second screen mesh is 90-110 mesh, and the mesh number of the third screen mesh is 120 mesh.

6. The beneficiation system for improving the grade of iron fines according to claim 1, wherein the filter is a disc filter.

7. A beneficiation system to upgrade fine iron powder according to claim 1, further comprising: a sand pump pool;

The input end of the sand pump pool is communicated with the output end of the grade 1 lifting machine; the output end of the sand pump pool is communicated with one of the input ends of the cyclone.

8. The beneficiation system for improving the grade of iron fines according to claim 7, wherein the sand pump tank is provided with a slurry pump.