EA041422B1 - SYSTEM AND METHOD FOR DRY GRINDING TO REDUCE WASTE DEHYDRATION, INCREASE FLOTATION EFFICIENCY, OBTAIN DRYER WASTE AND PREVENT FILTER MEDIUM Clogging - Google Patents

Description

Links to related applications

The patent claims priority in Provisional Application US 62/834014, filed April 15, 2019.

Field of invention

The invention relates to flotation circuits and related process flow diagrams, in particular technologies using thickeners and/or filters to accumulate waste (tails) after flotation circuits.

Embodiments of the disclosed system and method use a dry grinding process (e.g., a grinding process using a vertical roller mill or high-pressure grinding rollers - HPGR), followed by a dry sorting step so that fines (e.g., those passed by a P ₈₀ sieve are less 20 µm) could bypass the subsequent steps of flotation, settling and dewatering by filtration. This can improve the performance of the flotation circuit, avoid clogging the downstream filter cloth, and provide drier and more stable settling ponds (tailing ponds) than conventional wet milling methods used in mineral processing.

It is clear from the present disclosure that the dry grinding system and process embodiments described herein offer other advantages and benefits not achieved in other prior art mineral processing processes.

State of the art

According to FIG. 1 representing the state of the art, cement production typically includes a dry grinding process 1 in which a truck 2 loads an ore 3 such as limestone into a coarse crusher 4 such as a cone crusher. The unloaded product 5 from the coarse crusher 4 or the coarse crushing circuit is accumulated in the dump 6. Part 7 from the dump 6 is fed into the slat conveyor 8. The slat conveyor 8 unloads the material 9 onto the first conveyor 10, which feeds the material 11 into the buffer hopper 12. Material 13, unloaded from the buffer hopper 12 enters the hopper feeder 14. The unloaded material 15 from the hopper feeder 14 is fed into the screen 16, such as a vibrating screen, a double-layer screen, or a sorting device according to size or particle size of another type. In FIG. 1 shows a vibrating sieve with a double mesh. The coarser particles 17 leaving the screen 16 by overflow (top product) are sent to the second conveyor 18, while the under screen product 19 (bottom product) screening leaving the screen 16 is sent to the third conveyor 23. Discharged from the second conveyor 18, the material 20 serves as raw material for a secondary crusher 21 or a secondary crushing circuit, such as a coarse separation circuit with simultaneous grinding, including a secondary crusher 21, such as a cone crusher.

The size of the material 22 after the secondary crusher 21 is smaller than the size of the raw material 20 at the input of the crusher 21. The material 22 withdrawn from the secondary crusher 21 may eventually be transferred to the third conveyor with the underscreen product 19 screening coming from the screen 16, and recycled material 41 from a vertical roller mill (VRM) 32 such as a FLSmidth®OK™ mill. The material combination 24 after the third conveyor 23 passes under the magnetic tape separator 25 to remove foreign metal etc. from the material 24 after the third conveyor 23. The material 26 substantially free of foreign metal passes to the fourth conveyor 28 through the metal detection system 27 for ensuring that the material 26 is free of metal before it enters the separating device 30. The material 29 diverted from the fourth conveyor enters the separating device 30, and part of this material 29 is destined for use as raw material 31 of the vertical roller mill 32.

Air or gas 43 enters the vertical roller mill 32 from the fan 42, creating a fluidized bed to form a suspension of fine particles, separating them from large particles. Fine particles 33 suspended inside the vertical roller mill 32 are finally removed from it and fed as raw materials to a bag filter (dust collector) 34. The filtered air 35 is removed from the bag dust collector 34 by a fan 36, while the air 37 can be returned to atmosphere or reintroduced by the fan 42 into the vertical roller mill 32 as air/fluidized bed gas 43. The product leaving the baghouse 34 containing dry fine particles 38 can be used in cement production technology.

The coarse product 39 discharged from the vertical roller mill 32 can be fed to the fifth conveyor 40, which transfers the secondary raw material 41 to the third conveyor 23 for mixing with the undersize screening product 19 and the material 22 discharged from the secondary crusher 21.

In FIG. 2 shows a wet milling process 100 commonly used in mineral processing processes, generally comprising the addition of water or liquid 101 to crushed or pre-sized ore feedstock 102. Feedstock 102 may be the product of an upstream coarse crusher and/or crusher circuit. secondary crushing (not shown). The upstream primary and/or secondary crusher may be similar to that previously described with reference to FIG. 1.

The combined wetted raw material 103 enters the wet mill 104, for example,

- 1 041422 autogenous grinding mill (AGM) or semi-grinding mill (SGM), ball mill, rod mill or other type of fine grinding mill (e.g. attrition mill, stirred media mill, FLSmidth VXPmill™, Glencore Xtrata IsaMill™, etc. ). The material 105 exiting the wet mill is fed to one or more hydrocyclones 106, in which the overflow 107 of the hydrocyclone overflow from the one or more hydrocyclones 106 contains fine fractions (for example, having a particle size distribution (PSD). distribution), characterized by a size of less than 10 microns) leaving the tailings in the form of wet fines, requiring dehydration in at least one filter 115. The hydrocyclone bottoms drain 108 contains a coarse fraction of the raw material 105 supplied to the flotation circuit 109, which may include a battery flotation cells, one or more flotation cells, one or more flotation liquid pre-treatment tanks, rougher flotation cells, control flotation cells, etc. Product 110 from flotation circuit 109 may be further processed, and tailings 111 from flotation counter 109 may be dewatered in a settling tank, concentrator, or clarifier settling tank 112 when purified fluid 113 is captured (e.g., to reuse process water) , and the thickened bottoms product (e.g., sludge) 114 is combined with the wet fines 107 exiting the hydrocyclone 106. The combination of thickened product 114 and wet fines 107 is dewatered in at least one filter 115. Dehydrated tailings 116 after a filtration process (typically in the form of caked sludge) are carried by the conveyor, accumulated 117 and eventually enter the tailings storage 118, which can be enclosed by a dam 119.

The main disadvantage of such processes 100, such as the process shown in FIG. 2 is that wet fines 107 clog the filter media during filtration in the filter(s) 115. Wet fines also require more force, which complicates the dewatering of the sludge, requiring larger concentrators and greater applied force in the filter(- ax) 115. Accordingly, it is usually necessary to use filter presses instead of vacuum filters.

Another important disadvantage of such processes 100, such as the process shown in FIG. 2 is that some fines (eg, having a PSD of less than 20 µm) may pass into the flotation circuit 109 and degrade efficiency, recovery, reagent consumption, and/or adversely affect the operation of the flotation circuit 109.

Another disadvantage of such processes 100, such as the process shown in FIG. 2 is that wet fines in dehydrated tailings 116 from downstream filter(s) 115 or concentrators 112 can create instability in tailings ponds 118. Accordingly, the destruction of the tailings dam 119 can have catastrophic consequences.

Objectives of the invention

Thus, the object of the invention is to provide a system and method using dry grinding instead of wet grinding in order to save water.

Another object of the embodiments of the invention is to provide a system and method that overcomes the above problems associated with known processes.

Another object of the embodiments of the invention is to provide a system and method to avoid problems in the flotation circuit caused by fines.

It is yet another object of the embodiments of the invention to provide a system and method to avoid tailings dewatering problems in downstream processes, such as filter media clogging due to insufficient dewatering of solids, such as fines, that are filtered before being disposed of in the form of tails.

Yet another object of the embodiments of the invention is to provide a system and method for avoiding too much wet fines being sent to a waste disposal site (eg, a tailings facility), which could compromise geological stability.

It is yet another object of the embodiments of the invention to provide a system and method for improving the geological stability of tailings disposal sites by combining dewatered tailings with dry fines (e.g., particles smaller than 20 µm) that would adversely affect flotation processes and /or further dehydration processes.

These and other objectives will become apparent upon consideration of the accompanying drawings, which are described in this disclosure.

Although it is believed that every object can be solved in at least one embodiment of the invention, it is not necessary that in one embodiment of the invention all objects of the invention be solved.

It should be noted that embodiments of the invention may be particularly suitable for use in industries related to, inter alia, the processing of gold, phosphates, iron ore, rare earths, mineral sands or platinum group metals (PGMs).

- 2 041422

The essence of the invention

The present invention discloses a mineral processing system 200, 300 for recovering commercially valuable metal ore particles from ore 3. The mineral processing system 200, 300 may include a flotation circuit 109 and a dry grinding circuit preceding it. The dry grinding circuit may include a vertical roller mill 32 or a roller crusher 302. It is contemplated that both a vertical roller mill 32 and a roller crusher 302 may be used in some embodiments. The dry grinding circuit also includes at least one dry air particle separator 201, 304, 307 located between the vertical roller mill 32 or roller crusher 302 and the flotation circuit 109. At least one dry air particle separation device 201, 304, 307 may be configured to produce a dry fines stream 38 and a dry coarse fraction stream 202.

Coarse stream 202 from at least one dry air particle separator 201, 304, 307 may be introduced into a flotation circuit 109 to recover said commercial metal ore particles. The dry fines stream 38 from at least one dry air particle separation device 201, 304, 307 may be combined, in particular, with dehydrated tails 116, such as dehydrated tails 116 obtained from material 110, 111 withdrawn from circuit 109 flotation.

In embodiments, dry fines stream 38 may be combined with dehydrated tailings 116, in particular, in a mixing device 204. In embodiments, a mixing device 204 may be installed, in particular, before storage equipment 117 and/or tailings 118.

In embodiments, between the mixing device 204 and the flotation circuit 109, in particular, a concentrator 112 can be installed. Between the mixing device 204 and the concentrator 112, if necessary, a filter 115 can be installed, configured to further dehydrate the material 114 leaving the concentrator 112 In such embodiments, concentrator 112 and filter 115 may be configured to dewater material 110, 111 exiting flotation circuit 109 and/or feed dewatered tailings 116 to mixer 204, among other things.

In some embodiments, the implementation of the particle size distribution of the stream 38 dry fines may be characterized, in particular, the size of less than 20 microns. In some embodiments, the implementation of the particle size distribution of the stream 38 dry fines may be characterized, in particular, the size of less than 15 microns. In some embodiments, the implementation of the particle size distribution of the stream 38 dry fines may be characterized, in particular, the size of less than 10 microns.

The particle size distribution of the dry coarse fraction stream 202 has a particle size distribution characterized by a particle size greater than that of the dry fine fraction stream 38. In some embodiments, the implementation of the particle size distribution of the stream 202 dry coarse fraction can be characterized, in particular, the size of more than 10 microns. In some embodiments, the implementation of the particle size distribution of the stream 202 dry coarse fraction can be characterized, in particular, the size of more than 15 microns. In some embodiments, the implementation of the particle size distribution of the stream 202 dry coarse fraction can be characterized, in particular, the size of more than 20 microns.

In some embodiments, one dry air particle separation device 201, 304, 307 may be selected from the group consisting, in particular, of a hard rock sorting device, an air separator, a static separator, a static sand separator, a dust settling chamber, a V-separator, dynamic separator, rotary air separator, centrifugal separator, first generation turbo separator with one or more internal drum cyclones, second generation centrifugal separator with one or more external cyclones, third generation squirrel-cage separator, ROKSH dynamic separator, O-Sepa dynamic separator ®, cyclone gas separator, static suspended bed separator and cyclone dust collector. In some embodiments, the mineral processing system 200, 300 may specifically comprise a large number of dry air particle separation devices 201, 304, 307.

In some embodiments, between the at least one dry air particle separation device 201, 304, 307 and the mixing device 204, a dust bag 34 may be installed, in particular. In some embodiments, a magnetic separator 310 may be used. The magnetic separator 310 may be installed after the bag dust collector 34. The magnetic separator 310 is configured to carry out magnetic separation of the dry fines stream 38 and extract magnetic particles or ferromagnetic minerals 311 from it.

Also described is a method for extracting commercially valuable metal ore particles from ore 3 using mineral processing systems 200, 300. The method may include the step of crushing the ore 3 to obtain raw material 31 for the dry grinding circuit. The way can

- 3 041422 include a step of dry grinding of raw materials 31 in the dry grinding circuit (for example, using a vertical roller mill 32 or a roller crusher 302). The method may include the step of supplying product from the vertical roller mill 32 or roller crusher 302 to the dry air particle separator 201, 304, 307. The method may include the step of forming a dry fines stream 38 and a dry coarses stream 202 using a dry air particle separator 201, 304, 307.

The method may include the step of performing flotation in relation to the flow 202 dry coarse fraction in the circuit 109 flotation. The method may include the step of dewatering the material 110, 111 exiting the flotation circuit 109 to produce dry tails 116. The method may include the step 204 of mixing the dry fines stream 38 with the dry tails 116.

The step of dewatering the material 110, 111 leaving the flotation circuit 109 to produce dehydrated tailings 116 may include a thickening step 112 of the material 110, 111 leaving the flotation circuit 109. The step of dewatering the material 110, 111 leaving the flotation circuit 109 to produce tailings 116 may include a filtration step 115 of the material 110, 111 leaving the filtration circuit 109. The method may also include the steps of magnetically separating 310 the dry fines stream 38 and extracting magnetic particles or ferromagnetic materials 311 from it.

Disclosed is a dry grinding system and method for use in mineral processing. The dry grinding system and method may be used/introduced as part of the mineral processing system 200, 300 to extract commercially valuable metal ore particles from ore 3. The dry grinding system may include at least one particle separation device 201, 304, 307 dry air, adapted to form, in particular, the dry fines stream 38, the particle size distribution of which is characterized by a particle size distribution of less than 20 microns (for example, less than about 10 microns), and the dry coarse fraction stream 202 with a particle size distribution, characterized by a particle size distribution of more than about 10 microns ( for example, about 20-300 µm).

The coarse stream 202, mixed with water prior to entering the flotation machine, may be fed to a flotation circuit 109 to recover commercially valuable metal ore particles from the ore 3 contained in the dry coarse fraction stream 202. However, dry fines stream 38 (or a portion thereof) may remain unprocessed in flotation circuit 109 and may instead be combined with dehydrated tailings 116 obtained from material 110, 111 withdrawn from flotation circuit 109. Any of streams 110 or 111 may be a dewatering tails stream 112, 115, depending on the particular process (eg, conventional flotation or reverse flotation). Accordingly, although not shown here, stream 110 (more likely than stream 111) may in particular be dewatered and/or sent to tailings.

Brief description of the drawings

As a supplement and to facilitate understanding of the features of the present invention, a set of drawings is attached to the description, depicting new and original dry grinding systems and methods, representing an integral part of the disclosure and illustrating the following description of the invention without limiting its scope.

in fig. 1 shows a typical dry grinding system used in the cement industry;

in fig. 2 shows a typical wet grinding system used in the mining industry, in particular for the flotation process;

in fig. 3 shows a dry grinding system in accordance with a non-limiting embodiment of the invention, which will be described in more detail below.

Hereinafter the invention will be described in more detail with reference to the drawings illustrating particular embodiments.

Detailed description of the invention

While the present invention has been described herein in terms of particular embodiments of a dry milling system and process for flotation followed by dewatering to remove tailings, it should be appreciated that one of ordinary skill in the art, having read the foregoing disclosure, will be able to appreciate its many variations and adaptations.

Detailed illustrations and descriptions of embodiments given in the text and drawings should not be taken as limiting the scope of claims; on the contrary, all design features should be considered as an illustration or suggestion. Accordingly, the present invention is only limited by the appended formula.

Moreover, while this subject matter has been disclosed with reference to specific embodiments, it is obvious that other embodiments and modifications may be proposed by those skilled in the art without departing from the spirit and scope of the subject matter described herein. The appended claims may include some, but not all, of such embodiments and equivalent modifications.

With respect to the ranges given in this disclosure, they may include each of the above and below values. All patent publications cited herein are hereby incorporated by reference in their entirety and in all respects as if they were included in this specification.

The inventor proposed a new and hitherto unknown system and method for supplying raw materials to the flotation circuit and tailings. Embodiments are based on the idea of the invention to reduce the amount of fines (in particular, particles smaller than 20 microns) processed in the flotation circuit 109, followed by dehydration (for example, using settling equipment 112 and/or filtration equipment 115). Embodiments also use the inventive concept of dry grinding the ore (as is done in cement production) prior to flotation, instead of wet milling prior to flotation as is traditionally used in mineral processing, thereby reducing water consumption in the mineral processing process.

Embodiments also utilize the inventive concept of reducing the amount of wet fines 107 requiring filtration 115 before being diverted to tailings 118. Embodiments also utilize the inventive concept of adding dry fines from dry particle stream 38 to dehydrated tailings 116 (e.g., wet tailings or containing filtered material) after one or more tailings filters 115 and/or concentrators 112, to reduce the moisture content in the tailings and to dry out the tailings 118. In this case, the tailings 118 can be made more geostable in the event of an unforeseen catastrophic failure of the dam 119. The options described here implementation also provide separate disposal of dry fines 38 and dehydrated 114, 116 or containing little moisture 110, 111 tails.

In FIG. 3, in some embodiments, the illustrated dry grinding system and method 200 may include a vertical roller mill (VRM) 32, instead of a traditional wet mill 104. The system and method 200 may use a dry coarse separation with simultaneous grinding method according to the technology of cement production, similar to that shown in FIG. 1 and described in the Technical Field section of this specification.

The system and method 200 may include a dry grinding process 1 using a truck 2 delivering an ore 3 containing commercially valuable metal ore particles (e.g., iron, phosphates, rare earths, platinum group metal (PGM), gold, silver, etc.) , into a coarse crusher 4, such as a cone crusher.

The discharged product 5 from the coarse crusher 4 may be accumulated in the dump 6. The portion 7 of the dump 6 may be fed to the slat conveyor 8. The slat conveyor 8 may discharge the material 9 to the first conveyor 10 feeding the material 11 to the buffer hopper 12. The material 13 unloaded from buffer hopper 12 may enter the feed hopper 14. The discharged material 15 from the feed hopper 14 may be fed to a screen 16, such as a vibrating screen, a double-layer screen, or another type of size or particle size sorter.

Larger particles 17 leaving the screen 16 (for example, due to overflow) may be directed to the second conveyor 18, while the underscreen product 19 leaving the screen 16 may be directed to the third conveyor 23. Discharged from the second conveyor 18, the material 20 can serve as feedstock for a secondary crusher 21 or a secondary crusher circuit, such as a coarse separation circuit with simultaneous grinding, including a secondary crusher 21, such as a cone crusher. It should be noted that the secondary crusher 21 may include one or more crushers, and one or more crushers may include any type of secondary crusher, including but not limited to jaw crushers, hammer crushers, screen crushers, rotary cone crushers, etc. .

The size of the material 22 after the secondary crusher 21 is smaller than the size of the raw material 20 at the crusher 21 inlet. , and secondary raw material 41 from a vertical roller mill (VRM) 32 for example, mills FLSmidth®OK™, consisting of material 39 coarse fraction.

The combination of material 24 after the third conveyor 23 passes through a magnetic separator 25 (for example, under a magnet mounted above the belt) to remove foreign metal and the like. from material 24 on a third conveyor 23. Material 26, substantially free of foreign metal, may pass through a metal detection system 27 (e.g., on a fourth conveyor 28) to ensure that material 26 is free of metal before it enters the separating device 30. The material 29 diverted from the fourth conveyor can be sent to the separating device 30, and part of this material 29 entering the separating device 30 can be used as dry raw material 31 of the vertical roller mill 32 for dry grinding inside the vertical roller mill 32.

The vertical roller mill 32 may be supplied with air or a fluidized bed gas 43 from a fan 42 to form a suspension of fine particles so as to prevent them from further pulverization. The characteristics of the fluidized bed air or gas 43 can be

- 5 041422 be selected so that larger particles are not affected and remain on the grinding table inside the vertical roller mill 32, or exit the mill 32 as shown by arrows 39. Fine particles 33, which are in suspension inside the vertical roller mill 32, can be diverted (eg by a cyclonic swirl or fan) from the vertical roller mill 32 and used as feedstock for the downstream dry air particle separation device 201 for particle size separation and size sorting.

In some particular embodiments, the dry air particle separator 201 may comprise a hard rock screen or air separator, such as: Taiheiyo Engineering O-SEPA V separator, FLSmidth® O-SEPA® separator, FLSmidth® SEPAX® separator, FLSmidth separator ® ROKSH or V-separator, Sepmaster model separator, VSK® model separator supplied by KHD Humboldt Wedag GMBH or similar.

It should be appreciated that the dry air particle separation apparatus 201 may include, among other things, a static separator (eg, a static sand separator, a centrifugal separator, a V-separator, or a dust settling chamber). In some embodiments, it is desirable that the dry air particle separator 201 include a dynamic separator, for example: a turbo separator (eg, an intra-drum cyclone separator, often referred to as a first generation separator); cyclone separator (for example, a sorter with one or more remote cyclones, often referred to as a second generation separator); or a squirrel-cage separator (for example, a squirrel-wheel rotor sorter, often referred to as a third generation separator or a high efficiency separator). In some embodiments, the dry air particle separation device 201 may include, among others, a rotary air separator, a centrifugal separator, a cyclone gas separator, a static suspended bed separator, and a cyclone dust collector.

The bottom product 202 may be mixed with water prior to the flotation process 109 . The bottom product 202 from the dry air particle separator 201 preferably has a particle size distribution (PSD) with a particle size, in particular at least about 10 microns or more, preferably more than about 20 microns.

The top product 203 of the dry air particle separator 201 preferably has a particle size distribution (PSD) with a particle size, in particular, at least less than about 20 microns, and more preferably less than about 10 microns. The overhead product 203 may be directed to the baghouse 34. The filtered air 35 exiting the baghouse 34 may be evacuated (for example by a fan 36) to the atmosphere, or may in particular be reused by feeding it by the fan 42 into the vertical roller mill 32 as creating a fluidized bed of air/gas 43. Coarse particles of the bottom product 202 device 201 particle separation dry air can be fed into the circuit 109 flotation. In some cases, underflow 202 may be introduced into the flotation liquid pretreatment tank along with water and reagents. In some cases, the bottom product 202 may, in particular, be fed into the coarse, or control, flotation cell.

The dry fines product 38 exiting the bag filter 34 may be sent to a mixing device 204 (e.g., an auger mixer), or alternatively added to and/or combined with dewatered tailings 116 exiting one or more filters. 115 or concentrators 112. Accordingly, the moisture content of the dehydrated tailings 116 after passing through the filter(s) 115 and/or concentrator device(s) 112 can be reduced by the dry fines 38 sucking residual moisture from the dehydrated tailings 116. Combining the dry fines 38 with the dehydrated tailings 116 may occur, in particular, during, before or after the transfer or disposal in the dump 117. Preferably, the combination of the dry fines 38 and the dehydrated tailings 116 is performed before being deposited in the tailings 118, as shown in the drawings. .

The flotation circuit 109 may include, but is not limited to, a battery of flotation cells, one or more flotation cells, one or more flotation liquid pre-treatment tanks, one or more coarse flotation cells, one or more control flotation cells, and so on. Product 110 from flotation circuit 109 may be further processed, and tailings 111 from flotation circuit 109 may be subjected to dewatering in a settling tank, concentrator, or clarifier 112. Purified fluid 113 may be collected during a settling process (e.g., for settling). reuse), and the concentrated drain (eg, cake) 114 after the concentrator device 112 can subsequently be dehydrated in at least one filter 115 or, in particular, no longer be dehydrated. The tailings 114 and/or dehydrated tailings 116 remaining after the filtration process (typically caked sludge) can be combined with the dry fines 38 exiting the baghouse 34 to improve the geo-stability of the tailings storage site 118, particularly in the event of a catastrophic failure. 041422 dam 119 of the tailings.

In FIG. 4, in accordance with some embodiments, the illustrated dry grinding system and method 300 may comprise a roller crusher 302, such as a roller press, roller mill, or high pressure grinding rollers (HPR), instead of a traditional wet grinding mill 104.

The ore 3 is transported by trucks 2 to a coarse crusher 4, such as a cone crusher or crusher. The material 5 after the coarse crusher 4 can pass through the magnetic separator 25 and/or the metal detection device 27, after which it enters the screen 16 (in particular, a double vibrating sieve). Larger particles 17 of the ore 3 may be fed as raw material 11 into the buffer hopper 12. The contents 13 of the buffer hopper 12 may be discharged to a secondary crusher (for example, one or more secondary crusher 21, (for example, a cone crusher shown in the drawing). in particular, any type of secondary crusher 21 (for example, a screen crusher, hammer crusher, jaw crusher, or the like) can be used in particular. The double crusher material 22 after the secondary crusher 21 can be combined with the screen feed 15 passing through the magnetic separator 25 and/or the metal detection device 27. The undersize screening product 19 passing through the screen 16 can be fed into the buffer hopper 12 and its contents 13 are placed on the weight belt feeder 301 and fed as raw material 31 into the roller crusher 302 (in particular, a roller press or high-pressure chopping rollers (HPV)).

The discharged product 303 of the roller crusher 302 may be directed to a dry air particle separator 304, such as an FLSmidth® ROKSH cement separator or other dry air particle separator 201 mentioned earlier in this specification. Fluidized bed air or gas 43 may be introduced into the dry air particle separator 304 as shown in the drawing to create a suspension of fine particles within the dry air particle separator 304 .

Large particle size distribution (PSD) stream 305 (eg, underflow of dry air particle separator 304) can be sent back to roll crusher 302 as a coarse recycle.

A fine particle size distribution (PSD) stream 306 (eg, an overhead particle stream from a dry air particle separator 304) can be directed to a dust settling chamber 307 as shown. The overhead product 308 that is discharged from the dust settling chamber (eg, fines) may be directed to a dust bag. A damper 309 may be used to control the flow of filtered air 35 from the dust bag 34.

Similar to the system and method 200 shown in FIG. 3, an embodiment of the system and method 300 shown in FIG. 4 may include dry fines 38 exiting baghouse 34 and combined with dewatered tailings 116 (eg, at the exit of one or more filters 115 and/or concentrators 112 as shown). The filter(s), when used, may in particular include a vacuum filter or a pressure filter, such as a filter press. Dehydrated tailings 116 may, in particular, contain some moisture and appear as a filter cake. Dehydrated tailings 116 may consist of solid particles after processing in the circuit 109 filtration. It should be understood that in any of the embodiments disclosed herein, the dehydrated tailings 116 combined with the dry fines 38 may specifically contain some or all of the unfiltered solids from the concentrator underflow 114. In cases where a filter 115 is used, the dehydrated tails 116 may specifically include only filtered tails or a combination of filtered tails and concentrator bottoms 114.

By intentionally directing the dry fines 38 around the flotation circuit 109, its performance can be improved. By purposefully combining the dry fines 38 with the wet dehydrated tailings 116 from the material 111 exiting the flotation circuit 109 (e.g., in the mixer 204), the geostability of the tailings in the downstream tailings facility 118 can be improved, reducing risks in the event of destruction of the dam 119 tailings. In addition, by purposefully directing the dry fines 38 around the flotation circuit 109, the need for the amount of material subjected to dewatering by settling 112 and/or filtration 115 can be reduced. media in/on filters 115 used to dehydrate material 110, 111 from flotation circuit 109. Although not shown in the drawings, dry fines 38 may also be disposed of separately from tails 110, 111, 114, 116. In yet other embodiments, a portion of dry fines 38 may be added to tails 110, 111, 114, 116 ( for example, by means of a mixer 204); the rest of the dry fines 38 can be disposed of separately.

In some embodiments, a magnetic separator and/or a magnetic separation step 310 may be used to process the dry fines 38 to remove magnetic particles or ferromagnetic minerals 311 from there. The removed materials may contain, in particular, iron, nickel and/or or cobalt. The magnetic separator 310 may include any means for removing ferromagnetic materials, including but not limited to: a plate magnet, a magnetic grid, a magnetic drum, a hump magnet, an overhead magnet, a magnetic drive pulley, a vertical bar magnet, a belt separator with a magnet on top, or others.

A contractor or other organization may supply or install any item numbered or identified herein to create the system and method 200 in accordance with embodiments of the invention. For example, one or more structures, components, or elements of an existing process flow sheet or loop may be removed from a customer's manufacturing facility, and one or more structures, components, or elements may be introduced into the same existing process flow sheet or loop to create an equivalent of those described herein. dry grinding system or process. The contractor or other organization may, in particular, accept a tender for the development of a project for the design, manufacture, supply, installation, commissioning or maintenance of such a system or method. A contractor or other entity may offer to design, supply, maintain, install, or operate a similar dry grinding system or method, or offer technology substantially similar to the dry grinding system or method disclosed herein, or provide the customer with a process or related services. A contractor or other entity may propose a retrofit or may retrofit or improve the performance of an existing system or method using any or more of the components described herein to create a system or method in accordance with the embodiments described and/or claimed here. It is also contemplated that a contractor or other entity may, in particular in accordance with the inventive ideas and principles described herein, offer to an end user, client or customer to sell, sell, supply and/or install, among other things, one or more of the described vertical roller mills, hard rock sorters or mixers.

In the present description, the terms system, process, plant, process flow diagram, circuit, operation, and method may be used interchangeably.

It should be clear that when mentioning one feature, apparatus, component or device, several of the same features, apparatus, components or devices may be implied. Accordingly, in the present description, the indefinite article before a noun in most practical cases can be, in particular, replaced by the expression at least one of or more.

Although the invention has been described using particular embodiments and applications, it should be appreciated that a person skilled in the art, in view of the present disclosure, can develop additional embodiments and modifications without going beyond the spirit or scope of the claimed invention.

List of reference symbols in the drawings

- process/system/installation of dry grinding for the production of cement;

- truck;

- ore (for example, limestone);

- coarse crusher;

- unloaded product of rough crushing;

- dump;

- supplied raw materials to the plate conveyor;

- lamellar conveyor;

- unloaded material of the lamellar conveyor;

- the first conveyor;

- supplied raw material to the buffer hopper;

- buffer bunker;

- unloaded material of the buffer bunker;

- bunker feeder;

- material fed to the screen;

- screen (e.g. vibrating sieve, double-layer sieve);

- oversize (upper) screening product;

- the second conveyor;

- undersize (lower) screening product;

- feed material to the secondary crusher/second conveyor;

- secondary crusher (eg cone crusher);

- crushed product of secondary crushing;

- the third conveyor;

- discharged material of the third conveyor;

- 8 041422

- a magnet mounted above the tape;

- material substantially free of foreign metal;

- metal detection system;

- the fourth conveyor;

- discharged material of the fourth conveyor;

- separating device;

- raw materials for the dry grinding circuit (for example, raw materials for a vertical roller mill or raw materials for a roller crusher);

- vertical roller mill (VVM) (eg FLSmidth®OK™ mill);

- discharged fine fractions of the vertical roller mill (VVM) / raw material for the bag dust collector;

- bag dust collector;

- filtered air;

- fan;

- exhaust air;

- dry fines/dry fines stream;

- withdrawn coarse grinding of a vertical roller mill (VVM);

- the fifth conveyor;

- secondary raw materials;

- fan;

- air/gas creating a fluidized bed;

100 - wet grinding process/system/installation for mineral processing;

101 - water/liquid;

102 - raw material for the crushing part of the coarse fractions separation circuit with simultaneous grinding / discharged product of the crushing circuit;

103 - wet raw materials for crushing;

104 - wet grinding mill (for example, AG/SAG type mill, ball mill, rod mill, etc.);

105 - raw material for the hydrocyclone/unloaded product of the wet grinding mill);

106 - hydrocyclone;

107 - discharge of the upper product of the hydrocyclone (ie fine fraction);

108 - draining the bottom product of the hydrocyclone (i.e. large fraction);

109 - a flotation circuit (eg, a battery of flotation cells, one or more flotation cells, one or more flotation liquid pre-treatment tanks, etc.);

110 - product or material from the flotation circuit (the froth drain is shown, but there may also be a bottom product drain from the reverse flotation);

111 - tailings or material from the flotation circuit (bottom drain shown, but may also be froth drain from reverse flotation);

112 - tank/concentrator (e.g. settling, tailings dewatering)

113 - purified fluid;

114 - diverted product of the concentrator (for example, draining the bottom product, sediment, material at the exit of the concentrator);

116 - dehydrated tailings;

117 - accumulation / storage equipment (for example, conveyors, stackers, unloaders)

118 - tailings;

119 - tailings dam;

200 - process / system / installation of dry grinding for the processing of minerals;

201 - separator / device for separating particles with dry air;

202 - Hard Rock Screener/Air Separator Bottom Product (e.g. Coars with PSD over 20 µm, Feed to Flotation Circuit);

203 - hard rock sorting device/air separator top product (for example, fines with less than 20 µm PSD, raw material for bag dust collector);

204 - mixing device (for example, a screw mixer);

300 - process / system / installation of dry grinding for the processing of mineral raw materials;

301 - weight belt feeder;

302 - roller crusher (for example, high pressure roller press (HPR), roller press, roller mill, etc.);

303 - unloaded product of the roller crusher;

304 - separator/particle separation process with dry air;

305 - flow of particles whose particle size distribution (PSD) is characterized by a large size (for example, the flow of underflow particles from a dry separator, large secondary raw materials in HPGR);

306 - flow of particles, particle size distribution of which (PSD) is characterized by a small size

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Claims (9)

(for example, the flow of particles of the upper product from the dry separator); 307 - dust settling chamber; 308 - top product of the dust settling chamber (for example, fines); 309 - damper; 310 - magnetic separator; 311 - magnetic particles (for example, ferromagnetic minerals, for example, iron, nickel, cobalt). CLAIM 1. Installation (200, 300) for processing minerals to extract metal particles of industrial value from ore (3), including a flotation circuit (109); dry grinding circuit located in front of the flotation circuit (109) and containing a vertical roller mill (32) or roller crusher (302) and several devices (201, 304, 307) for separating particles with dry air, located between the vertical roller mill (32) or roller a crusher (302) and a flotation circuit (109); storage equipment (117) and/or tailings (118); a mixer (204) placed downstream of storage equipment (117) and/or tailings (118); a concentrator (112) installed between the mixer (204) and the flotation circuit (109); a filter (115) installed between the mixer (204) and the concentrator (112), wherein the devices (201, 304, 307) for separating particles with dry air are configured to create a stream (38) of a dry fine fraction and a stream (202) of a dry coarse fraction, so that the coarse fraction stream (202) is fed into the flotation circuit (109) to recover said metal ore particles of industrial value, and the dry fine fraction stream (38) is combined with dehydrated tailings (116) obtained from the material (110, 111), leaving the flotation circuit (109), while the dry fines stream (38) is combined with dehydrated tailings (116) in the mixer (204), and the concentrator (112) is configured to dehydrate the material (110, 111) leaving the circuit ( 109) flotation, and supply of dehydrated tailings (116) to the mixer (204), and the filter (115) is configured to further dehydrate the material (114) discharged from the concentrator (112). 2. A mineral processing plant (200, 300) according to any one of the preceding claims, wherein the particle size distribution of the dry fines stream (38) is less than 20 µm. 3. A mineral processing plant (200, 300) according to claim 2, wherein the particle size distribution of the dry fines stream (38) is less than 15 µm. 4. A mineral processing plant (200, 300) according to claim 3, wherein the particle size distribution of the dry fines stream (38) is less than 10 µm. 5. A mineral processing plant (200, 300) according to any one of the preceding claims, wherein the particle size distribution of the dry coarse fraction stream (202) is larger than the dry fine fraction stream (38). 6. The mineral processing plant (200, 300) according to any one of the preceding claims, wherein the dry air particle separation devices (201, 304, 307) are selected from the group consisting of a hard rock sorting device, an air separator, a static separator, a static separator sand, dust settling chamber, V-separator, dynamic separator, rotary air separator, centrifugal separator, first generation turbo separator with one or more internal drum cyclones, second generation centrifugal separator with one or more external cyclones, third generation squirrel cage rotor separator, ROKSH dynamic separator, O-Sepa® dynamic separator, cyclone gas separator, static suspended bed separator and cyclone dust collector. 7. The mineral processing plant (200, 300) according to any one of the preceding claims, further comprising a bag dust collector (34) installed between the dry air particle separation devices (304, 307) and the mixer (204). 8. Mineral processing plant (200, 300) according to any one of the preceding claims, further comprising a magnetic separator (310) configured to magnetically separate the dry fines stream (38) and extract magnetic particles or ferromagnetic minerals (311) from it. 9. A method for extracting industrially valuable metal particles from ore (3) using a mineral processing plant (200, 300) according to any of the previous claims 1 to 8, in which ore (3) is crushed to obtain raw materials (31) for a dry circuit grinding; perform dry grinding of raw materials (31) in a dry grinding circuit using a vertical roller mill (32) or a roller crusher (302); send the product from the vertical roller mill (32) or roller crusher (302) to the