EP2812117A1

EP2812117A1 - Plant for crushing mineral materials

Info

Publication number: EP2812117A1
Application number: EP13706650.2A
Authority: EP
Inventors: Marcel Bourgeois
Original assignee: Vicat SA
Current assignee: Vicat SA
Priority date: 2012-02-08
Filing date: 2013-02-07
Publication date: 2014-12-17
Also published as: US20150053800A1; WO2013117864A1; IN2014DN06702A; CA2863849A1; FR2986445B1; FR2986445A1

Abstract

The invention concerns a plant (50) for crushing mineral materials comprising: - a hermetic enclosure (2); - at least one press (30) housed inside the enclosure (2), arranged to crush the mineral materials; - at least a first separator (42) housed inside the enclosure (2), arranged to separate: residual coarse particles from the roller press (30); and fine particles and intermediate particles from the roller press (30); - a second separator (27) housed inside the enclosure (2), arranged to separate the fine particles from the intermediate particles; and - suction means configured to extract only the fine particles via a first extraction duct (8).

Description

MINERAL MILLING FACILITY

The present invention relates to a grinding plant for mineral materials, in particular for the equipment of a cement plant.

Cement manufacturing involves a plurality of steps.

Classically, during an extraction stage, blocks of mineral matter are extracted from a quarry and then crushed. During a first grinding step, the crushed mineral materials are crushed to give a raw. During a cooking step, the raw is cooked at a temperature of about 1450 ° C to give a clinker. Finally, during a second grinding step the clinker is mixed with an additional crushed mineral material, for example gypsum, and then ground to give a cement of desired composition.

The electrical consumption generated by the operation of the first and second grinding stages represents between 50% and 80% of the total electricity consumption of a cement factory.

In a constant effort to reduce operating costs and the environmental impact of such factories, mineral grinding facilities have evolved over the last twenty years.

Until the 1980s, such plants used ball mills according to a grinding process which consists of passing the material to be grinded through a rotating horizontal tube containing metal balls. This grinding principle of the material has a very low energy efficiency.

Subsequently, the installations gradually evolved towards the principle of crushing into a bed of material that offers a more favorable energy efficiency. This has resulted in the adoption of vertical shredders. The strong gain in energy efficiency that has accompanied these technologies is counterbalanced by increased complexity of the installation and the need to wet the material to be grinded, which adds an additional step of drying expensive thermal energy.

Simultaneously, both metallurgical improvements and granulometric separation processes of the material have led to the development of milling with a roller press. This type of mill, which also uses the principle of crushing in a bed of material, offers both, by the use of gravity for the admission of the material, a reduced energy consumption and a simplification of the grinding plant. Today, the mineral material crushing plants with a roller press conventionally comprise a cascade-type static separator, a third-generation dynamic separator and a roller press.

Such an installation, if it is perfectly adapted to ensure adequate granulometry of the final product, consumes a still significant amount of energy.

In addition, the roller press, the cascade type static separator and the dynamic separator are arranged separately and must then be arranged inside a large workshop.

Such an installation requires the use of a high capacity elevator providing a circulating load of at least five times the flow of the installation. When the capacity of the elevator exceeds the limits of the technique, it is necessary to have two elevators in parallel, which increases the cost of installation.

Finally, such an installation can not accept a moisture content of mineral matter greater than 4%. Otherwise, the condensation phenomena are likely to cause the clogging of the rollers.

The invention aims to overcome all or part of these disadvantages.

The invention relates to a compact grinding plant for mineral materials, in particular for the equipping of a cement plant, characterized in that it comprises:

a hermetic enclosure extending in a vertical direction, said enclosure comprising at least a first mouth connected to a supply duct for mineral substances, a second mouth connected to a first fine particle extraction duct, a third connected mouth; a second coarse particle extraction pipe, and a fourth gas inlet mouth;

at least one roller press housed inside the enclosure in an intermediate portion thereof, the roller press being arranged to grind the mineral matter, so as to form fine particles, intermediate particles, and residual coarse particles;

at least one first separator, preferably of cascade type, housed inside the enclosure in a lower part thereof, arranged to separate: • on the one hand the residual coarse particles from the roller press for extraction by the second extraction duct; and

• other fine particles and intermediate particles from the roller press;

- A second separator, preferably dynamic, housed inside the enclosure in an upper part thereof, arranged to separate the fine particles from the intermediate particles, for the purpose of grinding the intermediate particles by the roller press; and

- Suction means configured to extract only the fine particles by the first extraction duct.

It should be observed that the installation according to the invention is not in any way connected in series, by conduits, a roller press, a first separateu r and a second separator housed in respective enclosures, but to be housed inside in the same enclosure at least one roller press, a first separator and a second separator.

By "vertical direction" is meant a substantially rectilinear direction from bottom to top.

For example, a third-generation dynamic separator uses centrifugal force to separate fine particles from intermediate particles, whereas first- and second-generation separators use only gravity.

The installation according to the invention finds for example application for the implementation of the first or the second grinding step.

Under operating conditions, the inorganic materials brought into the enclosure by the feed conduit are crushed by the roller press, forming residual coarse particles, intermediate particles and fine particles.

Residual coarse particles, intermediate particles and fine particles are separated by the first separator. On the one hand, the residual coarse particles are extracted by the second extraction duct, preferably to be crushed again.

On the other hand, the fine and intermediate particles are carried by an ascending gas stream in the vicinity of the second separator, in part by the suction means, participating in the circulation of said gas stream. The second separator separates the intermediate particles from the fine particles. On the one hand, the suction means extract the fine particles, light, by the first extraction duct. On the other hand, the heavier intermediate particles fall by gravity into the roller press, in order to be crushed again.

Mineral materials are fed from the supply line to the roller press, and from the roller press to the first gravity separator.

In addition, the main components of the installation are grouped in the same enclosure which limits the means of transfer of material from one component to another, and by su ite the energy consumption of the installation.

Only the residual coarse particles are extracted from the chamber by the second extraction duct, which makes it possible to minimize the quantity of particles that can be reintroduced into the chamber by the supply duct. Also, the energy and the capacity required for an elevator to collect the residual coarse particles from the second extraction duct and return these residual coarse particles to the supply duct are reduced.

Such an installation allows a circulation of mineral matter in the enclosure from top to bottom by gravity through the roller press and a flow of hot gas from bottom to top against the flow of mineral materials, through the press to rolls.

By "hot gas" is meant gases having a temperature between room temperature and 250 ° C.

Thus, the hot gases dry the mineral materials as soon as they are introduced into the chamber and then through the roller press. The hot gases also allow the heating of the installation and its maintenance temperature.

It is thus possible to introduce wet mineral materials directly into the enclosure. The moisture of the mixture to be grinded is no longer limited to 3 or 4% but can be compared to the humidity accepted by the vertical shredders with pebbles is 15%. The grinding operations are thus carried out at the optimum grinding temperature which is around 80/90 °. Thus, any drying operations prior to the introduction of mineral substances into the chamber can be eliminated. In addition, when the plant is used to make cement, it is possible to adjust the temperature of the hot gases at the exit of the roller press, so as to control dehydration of the gypsum.

In addition, the heavier intermediate particles entrained upward by the hot gases fall back by their own weight into the roller press without going to the second separator. The lighter intermediate particles are carried to the second separator where they are sorted with fine particles and returned to the roller press to be crushed again.

The intermediate particles are thus recirculated inside the chamber until they become fine particles that can be carried away by the hot gases to the second separator and then through the second mouth. More specifically, a portion of the intermediate particles is recirculated in the roller press under the effect of the second separator. Another part of the intermediate particles is recirculated in the roller press under the effect of gravity.

It is thus possible to reduce:

the quantity of particles recirculated outside the enclosure and thus reducing the capacity and the puissance of the conveying means outside the enclosure;

the quantity of intermediate particles entrained to the second separator;

- the size of the second separator resulting from the increase of the internal recirculation without passing through the second separator and the decrease of the external recirculation.

Finally, it is possible to reduce the pressure applied between the rollers, and consequently to improve the efficiency of the roller press (the efficiency being expressed in kWh / ton).

The installation according to the invention may comprise one or more of the following characteristics.

According to one characteristic, the enclosure is fixed.

According to another characteristic, the second mouth opens into the chamber in an upper part thereof, and the fourth gas inlet mouth opens into the chamber in a lower part thereof. Preferably, the second mouth opens into the chamber above the second separator, and the fourth gas inlet mouth opens below the first separator.

According to one characteristic, the roller press and the second separator are arranged inside the enclosure so as to provide a space to allow at least a portion of the intermediate particles carried by hot gases, in particular the heavier ones, from fall back into the gravity roll press without going through the second separator.

Preferably, the press comprises a device for adjusting the speed of the gas situated for example at the level of the median horizontal plane of the roller press. This device may comprise partially or completely closable openings.

In its preferred embodiment, the or each first separator comprises:

a grid arranged for disaggregating agglomerates of fine, intermediate and coarse residual particles from the roll press, and gu ider by gust the residual coarse particles towards the second extraction pipe, and

- Blowing means arranged to blow hot gases through meshes of said grid, so as to carry the fine particles and the intermediate particles from the roller press in the vicinity of the second separator.

Under operating conditions, the intermediate and fine particles from the roller press, which are light, are carried near the second separator by the hot gases blown through the mesh of the grid and by the suction means.

The fine particles are then aspirated through the extraction duct while the intermediate particles fall by gravity to be crushed by the roller press.

The coarser residual particles, heavier, are guided by the gate to the second extraction duct to be extracted from the enclosure, and reassembled to the supply duct.

Advantageously, the insufflation means comprise at least one gas insufflation duct opening into the chamber through the or each fourth mouth, said insufflation duct being fluidly connected to the first extraction duct, so that that the hot gases extracted the enclosure by the first extraction duct is reinserted into the chamber by the insufflation duct.

According to one characteristic, the plant comprises a second-stage separatory funnel for separating the intermediate particles discharged by this second separator, and the mineral substances brought by the supply conduit, and feeding the press. with these intermediate particles and these mineral substances.

The funnel then acts as a refusal cone.

Preferably, the conduct of the led and the second extraction pipe are each equipped with a sealing chamber.

Under these conditions, the pressure inside the chamber is not affected by the ambient air at atmospheric pressure during the supply of the mineral substances through the feed conduit or the extraction of residual coarse particles by the second extraction duct.

According to one characteristic, the installation comprises conveying means arranged to collect the residual coarse particles from the second extraction duct and to return these residual coarse particles to the supply duct.

According to one characteristic, the installation comprises:

a hopper fed with mineral matter, housed inside the enclosure above the roller press;

means for measuring a quantity representative of the quantity of mineral matter contained in the hopper, such as the mass or the filling level of the hopper.

The intermediate particles carried by the hot gases and returned by g ravité ns pass by the second d separator are advantageously collected by the hopper.

The measuring means allow a regulation of the quantity of material in the hopper, by increasing or reducing the flow of mineral material brought by the supply line according to the measurement.

According to another feature, the installation comprises closing means and adjustment adapted to adjust the thickness and the position of the material stream above the gap between the rollers.

For example, the shutter and adjustment means comprise: - Means of obturating obturation in a pos nition and closing position in a position, respectively, prohibiting and authorizing the feeding of the roller press of mineral materials;

first motorization means configured to move the closure means in their release position or in their closed position;

- Adjustable adjustment means relative to the sealing means; and

second motorization means configured to move the adjustment means relative to the closure means, to adjust the thickness and the position of the material stream above the gap between the rollers.

The closure and adjustment means may take the form of lower flaps and upper flaps arranged under the hopper.

The combination of the first and second shutter and adjustment means makes it possible to optimize the flow, expressed in tonnes per hour, and the efficiency, expressed in kilo Watt hour per ton (kWh / t), of the installation.

In addition, such an association improves the grinding stability of the roller press. In fact, the closure means make it possible to balance the power absorbed by each roller and the adjustment means make it possible to saturate the air gap between the rollers.

Advantageously, the or each roller press comprises at least a first and a second rollers rotatably mounted about substantially parallel axes, and adjusting means adapted to adjust the width of the air gap separating the first and second rollers.

Preferably the axes of the rollers are horizontal. Preferably, the or each roller press is associated with a respective first separator, each first separator comprising two portions of grids inclined with respect to each other, the grid portions having lower edges facing a respective second mouth and upper edges joined to each other and arranged in line with the air gap separating the first and second rollers.

Thus, the installation is equipped with a double separator. In one embodiment, the suction means comprise a fan disposed outside the enclosure. According to one feature, the second separator comprises a turbine rotatably mounted inside the enclosure and a plurality of fixed vanes inside the enclosure concentric with the turbine.

The invention will be better understood with the aid of the description which follows with reference to the appended schematic drawing showing, by way of a non-limiting example, a crushing plant for mineral materials according to the invention.

Figure 1 is a schematic front view of an assembly of a grinding plant according to the invention;

Figure 2 is a partial schematic side view of the assembly of Figure 1; and

Figure 3 is a partial schematic view of the installation equipped with all of Figures 1 and 2.

Figure 1 shows an assembly 1 for a grinding installation 50 (shown in Figure 3). The assembly 1 comprises a hermetic fixed enclosure 2 extending in a main vertical direction 4. The chamber 2 comprises an upper wall 2a, a lower wall 2b and at least one side wall 2c connecting the upper walls 2a and lower 2b.

The chamber 2 comprises a mouth 6 formed through the upper wall 2a. This mouth 6 is connected to an extraction duct 8 of fine particles.

The chamber 2 comprises two mouths 10 formed through the bottom wall 2b. The mouths 10 are connected to an extraction duct 12 of residual coarse particles. The extraction duct 12 is equipped with a sealing chamber 14, here of pendular type, and conveying means (not shown).

The chamber 2 comprises a mouth 16 formed through the side wall 2c. This mouth 16 is connected to a supply line 18 of mineral matter. The supply duct 18 is equipped with a sealing chamber 20, here with three valves. In a variant, the sealing chamber 20 may be of rotary cellular type.

The enclosure 2 finally comprises mouths 22 formed through the side wall 2c. These mouths 22 are connected to blowing ducts 24 of a hot gas (shown in Figures 2 and 3). The assembly 1 comprises a separator 27 housed inside the enclosure 2, in the upper part thereof. The function of the separator 27 is specified below.

The separator 27 is a third generation dynamic separator. The separator 27 comprises blades 28a fixed inside the chamber 2 and a turbine 28b rotatably mounted inside the chamber 2 in line with the mouth 6. The turbine 28 is adapted to adjust the fineness of the finished product, its speed being increased to refine the finished product and diminished to enlarge the finished product.

The assembly 1 comprises a funnel 26 or refusal cone housed inside the enclosure 2. The funnel 26 is disposed under the turbine 28, directly above the turbine 28 and arranged so that the duct 18 feeds the inorganic materials into it.

The assembly 1 comprises a press 30 housed inside the chamber 2 in an intermediate portion thereof. The press 30 is arranged to grind the mineral matter poured into the funnel so as to form fine particles, intermediate particles and residual coarse particles.

The press 30 comprises two rollers 32 rotatably mounted about substantially parallel axes. By way of example, the axes here are horizontal, and the rollers 32 have a substantially equal diameter.

The press 30 comprises adjusting means (not shown) adapted to adjust the width of the gap 34 separating the rollers 32.

The assembly 1 comprises a hopper 38 fed by the funnel 26. The hopper 38 is arranged between the funnel 26 and the press 30, directly above the funnel 38 and the press 30.

The assembly 1 comprises measuring means (not shown) of the mass of mineral matter contained in the hopper 38 or the height of the mineral matter contained in the hopper 38.

The assembly 1 further comprises closure and adjustment means 36 adapted to adjust the thickness and the position of the material stream above the gap 34 between the rollers 32.

The shutter and adjusting means 36 comprise:

- Closing means 40 movable in a closed position and in a release position, respectively, prohibiting and allowing the feeding of the roller 30 of mineral materials; first drive means 41, such as cylinders, configured to move the closing means 40 in their release position or in their closed position;

- Adjustment means 37 movable relative to the closure means 40; and

second drive means 39, such as cylinders, configured to move the adjustment means 37 relative to the closure means 40 so as to adjust the thickness and the position of the material stream above the air gap 34 between the rollers 32.

The assembly 1 comprises a separator 42 housed inside the enclosure 2, in the lower part thereof. The separator 42 is arranged to separate on the one hand the fine particles and the intermediate particles, and on the other hand the residual coarse particles from the press 30.

The separator 42 is a static separator of cascade type. The separator 42 comprises a grid 44 arranged to guide by gravity the residual coarse particles from the press 30 to the mouths 10.

In the embodiment shown, the gate 44 comprises two grid portions 44a, 44b inclined with respect to each other. The grid portions 44a, 44b each have a lower edge facing a respective mouth and an upper edge opposite the lower edge. The upper edges of the grid portions 44a, 44b are joined and arranged vertically above the gap 34 separating the rollers 32.

The separator 42 further comprises insufflation means arranged for blowing hot gas through meshes of the grid 44, so as to suspend fine particles and intermediate particles from the press 30 inside. the chamber 2 and allow their suction through the conduit 8 under the action of a fan 82 (shown in Figure 3) generating an upward gas flow inside the chamber 2.

The assembly comprises conveying means arranged to collect the residual coarse particles from the extraction duct 12 and to supply the feed duct 18 with these residual coarse particles. For example, the conveying means comprise a bucket elevator 46.

During operation of the assembly 1 the fan 82 and the blowing ducts 24 circulate an upward gas stream. Mineral materials are discharged through the feed conduit 18 into the funnel 26 and into the hopper 38 for crushing by the roller press 30.

The press mills coarse particles from hopper 38 to form residual coarse particles, intermediate particles and fine particles.

The intermediate particles and the fine particles from the press 30, light, are carried near the separator 27 by the ascending gas stream.

The separator 27 separates the intermediate particles from the fine particles. On the one hand, the fine particles, light, are sucked under the action of the fan 82 by the condu it 8. On the other hand, the heavier intermediate particles fall by gravity into the funnel 26, in order to be crushed by the roller press 30.

The size of the fine particles sucked by the cond u it 8 is determined by the flow of hot gas flowing in the chamber 2, and by the speed of rotation of the turbine 28b.

The residual coarse particles from the roller press 30, too heavy to be carried away by the air blown through the insufflation ducts 24, fall by gravity onto the grid portions 44a and 44b and are guided by the grid portions. 44a and 44b to the mouths 10, then are transported, for example by a bulk conveyor disposed in the extraction duct 12, to the conveyor 46 in order to replenish the supply duct 18.

The press 30 and the separator 27 are arranged inside the chamber 2 so as to provide a space 31 to allow the heavier intermediate particles carried by the hot gases to fall back into the press 30 by gravity, without passing through the separator 27.

When aggregates of intermediate particles and fine particles are formed in the press 30, the latter, too heavy to be carried away by the air blown through the insufflation ducts 24, fall by gravity onto the grid portions 44a, and 44b and disintegrate. The intermediate particles and the disaggregated fine particles are carried away in the vicinity of the turbine 28 by the hot gases injected by the insufflation ducts 24. The fine particles are then sucked by the extraction duct 8 while the intermediate particles fall back by gravity in the funnel 26. FIG. 3 shows the grinding installation 50 equipped with the assembly 1.

The installation 50 comprises a conveyor 52, here band.

The plant 50 comprises, for example, two hoppers 54 and 56 containing mineral substances, such as clinker and gypsum. The hoppers 54 and 56 are arranged to pour the clinker and the gypsum onto the belt of the conveyor 52 in a predetermined proportion and form a mixture of mineral materials. To this end, the hoppers 54 and 56 are each equipped with a 57 belt weigher.

The conveyor 52 feeds the supply duct 1 8 with said mineral granular composition.

The installation 50 comprises a sorting system 58 comprising:

a first metal detector 60 for detecting the presence of metal particles in the mineral mineral substances spilled on the belt of the conveyor 52;

a conduit 62 for redirecting the mineral matter disposed on the belt of the conveyor 52 to a buffer hopper 64, when the presence of metal particles is detected by the metal detector 60;

- A weigh feeder 66 strip, on which are discharged the mineral materials contained in the hopper 64;

a second metal detector 68 for detecting the presence of metal particles in the mineral substances discharged into the weight dispenser 64;

a conduit 70 for redirecting the mineral matter discharged onto the weight dispenser 66 to a reject hopper 72, when the presence of metal particles is detected by the metal detector 68; and

a conduit 72 for redirecting the mineral matter poured onto the weight dispenser 66 towards the conveyor 46, in the absence of detection of metallic particles by the metal detector 68.

The installation 50 finally comprises a filtration device 80 arranged to filter a mixture of gas and fine particles extracted from the chamber 2 by the extraction duct 8. In the example, the filtration device 80 comprises a filter 84 and the fan 82.

The fine particles extracted by the filtration device 80 are received in a hovercraft 86, and the hot gases through a ventilation duct 88. Hovercraft 86 conducts fine particles into a storage silo (not shown). The airlifter 86 is connected to the filter 84 by a sealing chamber 90, for example rotary alveolar.

The ventilation duct 88 is connected to the blowing ducts 24 by a recirculation duct 92. Thus, the blowing ducts 24 are fluidly connected to the extraction duct 8, and the hot gases extracted from the enclosure 2 by the extraction duct 8 can be re-bled in the chamber 2 by the insufflation ducts 24.

The ventilation duct 88 is connected to a chimney 94 by a discharge duct 96, so that an excess of hot and / or humid gas can be released.

The recirculation ducts 92 and evacuation 96, and the insufflation ducts 24 are equipped with valves, respectively, 98, 99, and 100, and a valve 1 01 fresh air intake for regulating the flow rate, the pressure, and the temperature of the gas blown into the chamber 2 by the insufflation ducts 24 or expelled by the chimney 94.

The invention is not limited to the single embodiment of the installation described above by way of example, it encompasses all the variants.

In a variant, the installation may comprise a plurality of roller presses arranged substantially at the same height inside the enclosure. Under these conditions, each roller press is preferably associated with a respective separator 42. Still alternatively, the rollers of each roller press may have the same or different diameters. The axes of the rollers may be arranged in a horizontal or oblique plane, that is to say forming a non-zero angle with the horizontal plane.

Alternatively, at least one roller may be movably mounted relative to the other roller by at least one hydraulic cylinder, to adjust the air gap and can be erased fa ce to a large particle conglomerate and hard brought to the roller press.

Still alternatively, the installation may comprise one or more cascade type separators each comprising a single portion of a grid extending in an oblique plane.

Claims

1. Plant (50) for grinding mineral materials, particularly for the equipment of a cement plant, characterized in that it comprises:

- a hermetic enclosure (2) extending in a direction (4) vertical, said enclosure (2) comprising at least a first mouth (16) connected to a supply duct (18) of mineral materials, a second mouth ( 6) connected to a first fine particulate extraction duct (8), a third mouth (10) connected to a second residual coarse particle extraction duct (12), and a fourth intake mouth (22). gas;

at least one roller press (30) housed inside the enclosure (2) in an intermediate portion thereof, the roller press (30) being arranged to grind the mineral matter, so as to form fine particles, intermediate particles, and residual coarse particles;

at least one first separator (42), preferably of cascade type, housed inside the enclosure (2) in a lower part thereof, arranged to separate:

• on the one hand the residual coarse particles from the roller press (30) for extraction by the second extraction pipe (12); and

· On the other hand the fine particles and the intermediate particles from the roller press (30);

- a second separator (27), preferably dynamic, housed inside the enclosure (2) in an upper part thereof, arranged to separate the fine particles from the intermediate particles, for the purpose of crushing the intermediate particles by the roller press; and

- Suction means configured to extract only the fine particles by the first extraction duct (8).

2. Installation according to claim 1, characterized in that the roller press (30) and the second separator (27) are arranged inside the enclosure (2) so as to provide a space (31) for allowing at least a portion of the intermediate particles carried by hot gases, especially the heavier, to fall back into the press (30) by gravity roll, without passing through the second separator (27).

3. Installation (50) according to any one of claims 1 or 2, characterized in that the or each first separator (42) comprises:

at least one gate (44) arranged to disaggregate agglomerates of fine, intermediate and coarse residual particles from the roller press (30), and to guide by gravity the residual coarse particles towards the second extraction pipe (12), and

- Blowing means arranged to blow hot gases through meshes of said grid (44), so as to carry the fine particles and the intermediate particles from the roller press (30) in the vicinity of the second separator (27). ).

4. Installation (50) according to claim 3, characterized in that the insufflation means comprise at least one insufflation duct (24, 92) of gas opening inside the chamber (2) by the or each fourth mouth (22), said insufflation duct (24, 92) being fluidly connected to the first extraction duct (8), so that the hot gases extracted from the enclosure (2) by the first duct of extraction (8) is re-insufflated in the chamber (2) by the insufflation duct (24, 92).

5. Installation (50) according to any one of claims 3 or 4, characterized in that the installation comprises a funnel (26) disposed under the second separator (27) for collecting the intermediate particles rejected by the second separator (27). ), and the mineral materials supplied by the feed duct (18), and feed the roller press (30) with these intermediate particles and these mineral substances.

6. Installation (50) according to any one of claims 1 to 5, characterized in that the supply duct (18) and the second extraction duct (12) are each equipped with a sealing chamber (2014).

7. Installation (50) according to any one of claims 1 to 6, characterized in that it comprises conveying means (46) arranged to collect the residual coarse particles from the second extraction duct (12) and for remount these residual coarse particles to the supply duct (18).

8. Installation (50) according to any one of claims 1 to 7, characterized in that it comprises:

- a hopper (38) supplied with mineral materials, l ogee inside the chamber (2) above the press (30) with rollers;

measuring means of a magnitude representative of the quantity of mineral matter contained in the hopper (38), such as the mass or filling level of the hopper (38).

9. Installation according to any one of claims 1 to 8, characterized in that it comprises closing means and adjusting (36) adapted to adjust the thickness and the position of the vein material above the gap between the rollers.

10. Installation according to claim 9, characterized in that the closing and adjusting means (36) comprise:

- Closing means (40) movable in a closed position and in a release position, respectively, prohibiting and allowing the feeding of the press (30) to rollers of mineral materials;

first drive means (41) configured to move the closing means (40) in their release position or in their closed position (40);

- Adjustment means (37) movable relative to the sealing means; and

second drive means (39) configured to move the adjustment means (37) relative to the shut-off means (40) for adjusting the thickness and position of the material stream above the gap (34) between the rollers (32).

1 1. Installation (50) according to any one of claims 1 to 10, characterized in that the or each roller press (30) comprises at least a first and a second roller (32) rotatably mounted about substantially parallel axes, and adjusting means adapted to adjust the width of the gap (34) separating the first and second rollers (32).

12. Installation (50) according to claim 1 1, characterized in that each roller press (30) is associated with a respective first separator (42), each first separator comprising two portions of grids (44a, 44b) inclined the relative to one another, the grid portions (44a, 44b) having lower edges facing a respective second mouth (10) and upper edges joined to each other and disposed vertically to the gap (34) separating the first and second rollers (32).

13. Installation (50) according to any one of claims 1 to

12, characterized in that the suction means comprise a fan disposed outside the enclosure.

14. Installation (50) according to any one of claims 1 to

13, characterized in that the second separator comprises a turbine (28b) rotatably mounted inside the enclosure (2) and a plurality of vanes (28a) fixed inside the enclosure (2) concentric with the turbine (28b).