FR2972947A1 - METHOD AND DEVICE FOR AGGLOMERATING A MIXTURE COMPRISING METAL DUST - Google Patents

Abstract

Method and device for implementing the agglomeration process of a mixture comprising metallic dust and a binder, comprising a step of pressing the mixture, the pressing comprising pressing by a press head in a mold 17 provided with a frame 61 and intermediate walls 66 oriented substantially parallel to the direction of the thickness of the frame 61 and provided with ribs 68 projecting in a direction in the plane of the frame 61 and elongate in a direction substantially parallel to the direction of the the thickness of the frame 61, the mold 17 being configured to form at least one cake, said ribs 68 forming grooves in said cake so as to make said cake breakable into chipboard portions.

Description

HLG MANAGEMENT 1 FRD 1 Process and device for agglomeration of a mixture comprising metallic dusts.

The present invention relates to the field of treatment of industrial waste containing metals. Many sectors, particularly the metallurgical industries, produce waste that contains metallic dusts. The waste is usually treated to extract metal dust that can be reused. The processes used to recycle this waste are expensive and / or polluting.

The increase in the cost of many metals, pushes the actors of the sector to optimize the valuation of waste.

The process relates more particularly to the field of agglomeration of mixtures comprising metallic dusts.

There are processes for agglomeration of dust or sludge containing metal particles. These methods include so-called "continuous" or "tangential" pressing using roller presses, most suitable for providing agglomeration in an industrially acceptable process time. The structure of aggregates is poorly defined and is difficult to control or reproduce. The aggregates produced do not allow easy handling for subsequent treatment. The heterogeneity of composition, shape and size of aggregates limits the effectiveness of subsequent treatments. The object of the invention is in particular to overcome the aforementioned drawbacks. In a first aspect, the invention relates to a method for agglomerating a mixture comprising metal dust and a binder, comprising a step of pressing the mixture, the pressing comprising pressing by a press head in a mold provided with a frame and intermediate walls oriented substantially parallel to the direction of the thickness of the frame and provided with ribs projecting in a direction in the plane of the frame and elongate in a direction substantially parallel to the direction of the thickness of the frame, the mold being configured to form at least one cake, said ribs forming grooves in said cake so as to render said cake breakable into chipboard portions. The method of the invention thus makes it possible to transform a substance in the form of dust or mud into a product that is easily handled and recyclable.

In a second aspect, the invention relates to a device for implementing the method comprising a mold provided with a frame and intermediate walls oriented substantially parallel to the thickness of the frame and provided with ribs projecting in a direction included in the plane of the frame and elongated in a direction substantially parallel to the direction of the thickness of the frame and a press head arranged complementarily to said mold to allow interpenetration of said mold and said press head.

Finally, the invention relates in a third aspect, the product obtained by the process, that is to say the breakable cake and the agglomerated portions.

On the other hand, the method and the device of the invention are particularly suitable for the use of hydraulic and inorganic binders, for example Portland cement. The use of inorganic binder is described for example in WO 91/01280 for immobilizing and inerting liquids or emulsions to be treated. However, this use usually requires so-called "continuous" or "tangential" pressing using roller presses capable of providing a pressing force for agglomeration in an industrially acceptable processing time. The products obtained by the process of the invention, combined with the use of inorganic binder, produce, during a subsequent melting, a small amount of unwanted gases. By unwanted gases is meant in particular gases that may be toxic and / or incompatible with environmental standards.

Other features and advantages of the invention will appear on examining the detailed description below, and the accompanying drawings, given solely by way of example, in which: FIG. 1 is a schematic diagram of a device for carrying out the process of the invention; FIG. 2A is a perspective view of a mold,

FIG. 2B is a schematic view of the top of the mold of FIG. 2A,

FIG. 3A is a perspective view of a press head, FIG. 3B is a schematic view of the underside of the press head of FIG. 3A, FIG. 3C is a schematic side view of the press head of FIGS. FIGS. 3A and 3B, FIG. 3D is a schematic side view of a press head along an axis perpendicular to that of FIG. 3C,

FIG. 4 is a perspective view of an assembly comprising a mold and a press head, FIG. 5 is a perspective view of a cake at the exit of the mold,

FIG. 6 is a perspective view of chipboard portions taken from cakes according to FIG. 5. The appended drawings are partly at least of a certain character and may serve not only to complete the invention, but also to contribute to its definition, if necessary.

As represented in FIG. 1, the process may comprise a homogenization step 100. The homogenization 100 comprises mixing a first mixture 1 with a binder 3. The first mixture 1 comprises recoverable metal particles. The first mixture 1 may comprise sludge. The first mixture 1 may include dust. The first mixture 1 can take the form of powder. The first mixture 1 is little or not recoverable as is. The homogenization 100 may comprise mixing the first mixture 1 with water 5. The homogenization 100 may comprise mixing. The mixing can be carried out by the use of a mixer 7. The first mixture 1 is, here, an industrial discharge of a metallurgical industry. The first mixture 1 may have undergone various treatments before homogenization 100. The first mixture 1 may have undergone, for example, crushing, washing, filtering, etc.

The metal elements may comprise, for example, without limitation, at least one of the elements of the group consisting of alumina, iron, platinum, molybdenum, chromium and nickel. The proportion of each metal element may be unknown in the first mixture 1.

Binder 3 is, here, an inorganic binder. The binder 3 is, here, a hydraulic binder.

The binder 3 may further comprise lime, particularly if the first mixture 1 is of too liquid consistency. The binder 3 may comprise, for example, Portland cement. The binder 3 may, in addition, be chosen for its properties during the future melting of the product obtained by the process.

After the homogenization step 100, a second mixture 11 is obtained. The second mixture 11 can comprise, for example, between 3 and 10% by weight of binder 3. The second mixture 11 may comprise, for example, between 6 and 15% by weight of water 5. The second mixture 11 generally has a pasty consistency. The second mixture 11 has the property of taking the form of its container.

The second mixture 11 can undergo a storage step 101. The storage 101 takes place in a suitable container 9, for example a bottom-opening tank. The storage step 101 may include agitation. Said agitation is advantageous in case of hardening property of the second mixture 11.

The second mixture 11 is poured into a conveying container 14, or drawer.

The conveying container 14 comprises, here, four substantially vertical walls arranged in a closed rectangle. The conveying container 14 is open at the top to receive the second mixture 11 from the container 9 of the storage 101 or directly from a chamber where the homogenization 100 takes place, for example the mixer 7. The conveying container 14 is open in its lower part. At the time of filling of the conveying container 14 with the second mixture 11, said lower part is obstructed by a bottom plate 15. The bottom plate 15 is arranged below and facing the conveying container 14 so as to form a bottom of the conveying container 14. The bottom plate 15 is fixed here. The conveying container 14 may have, for example, a capacity of about 30 liters.

The method comprises a pressing step 102. The pressing step 102 of the second mixture 11 is carried out by means of a mold 17 or frame, a press head 19 of a press 21 and a plate of support 22. The pressing 102 is made along a substantially vertical axis. In the embodiment of FIG. 1, the press 21 moves F3 from top to bottom at pressing 102.

The second mixture 11 is poured into the mold 17. The top of the mold 17 is open during its filling by the second mixture 11. The filling of the mold 17 is made by the top of the mold 17. According to the embodiment shown in FIG. the second mixture 11 is poured into the mold 17 from the conveying container 14. The conveying container 14 is adapted to undergo a substantially horizontal movement F 1 to come from a position substantially opposite and below the container 9 to a position substantially opposite and above the mold 17, from left to right in Figure 1. The displacement is achieved by means of a suitable actuator (not shown), such as a cylinder. The conveying container 14 moves the second mixture 11 horizontally towards the mold 17. The bottom plate 15 remains substantially immobile during the horizontal displacement of the conveying container 14.

The bottom plate 15 is arranged so that one of its edges is located near an edge of the mold 17. The conveying container 14, the bottom plate 15 and the mold 17 are arranged mutually so that during the horizontal displacement F 1 of the conveying container 14, the bottom plate 15 and the mold 17 remain stationary. During said displacement F1, the lower part of the conveying container 14 vertically and progressively misaligns the bottom plate 15 so that the lower part of the conveying container 14 opens above the mold 17. The second mixture 11 falls into the mold 17 by the opening of the lower part of the conveying container 14 and by gravity.

Alternatively, the second mixture 11 can be poured in controlled volume into the mold 17 from the container 9 adapted constituting a storage space 101, for example by a system of slide, slide, tube etc. The second mixture 11 can be poured into the mold 17 from the homogenization space 100, for example the kneader 7, for example by a slide system, slide, tube, etc.

As shown in FIGS. 2A and 2B, the mold 17 comprises a frame 61. The mold 17 comprises intermediate walls 66. The frame 61 comprises an assembly of four elongate elements 62 to 65. Each of said four elongated elements 62 to 65 forms one side of the frame 61. Among said elongate members, arbitrarily a first pair of left 62 and right side members 63 and a second pair of front 64 and rear 65 members will be arbitrarily designated. Each member of each pair being disposed opposite each other. -vis the other element of the same pair. Said elements 62 to 65 are respectively fixed with the two elements of the other pair by their respective ends.

The front 64 and rear 65 elements comprise blind holes 67. The blind holes 67 are formed from the outward facing surfaces of the frame 61. The blind holes 67 can be used for fastening the mold 17 with at least one member of a machine implementing the method, for example the press 21. The frame 61 has here a thickness of about 80 millimeters. The frame 61 is here substantially square side measuring about 400 millimeters.

The intermediate walls 66, or spacers, have a height substantially equal to the thickness of the frame 61. The intermediate walls 66 have a length between, the distance separating the facing surfaces facing each other and the frame 61 of the elements left side 62 and right 63, and the distance between the outwardly facing surfaces of the frame 61 of the left side members 62 and right 63. The intermediate walls 66, are fixed at their ends to each of the left side members 62 and right 63 The intermediate walls 66 may be attached by welding to the frame 61. The inward facing surfaces of the frame 61 of the left and right side members 62 and 63 comprise fixing grooves 69. The fixing grooves 69 are aligned in directions substantially perpendicular to the frame 61. The fixing grooves 69 are arranged to house the ends of the intermediate walls. 66. The intermediate walls 66 are fixed substantially parallel to the front 64 and rear 65 elements. The intermediate walls 66 are fixed substantially perpendicular to the inward facing surfaces of the frame 61 of the left 62 and right 63 side members. The intermediate walls 66 are fixed substantially parallel to each other within the frame 61. The intermediate walls 66 may be equidistant from each other. The intermediate walls 66 are, here, mutually spaced about 40 millimeters. The arrangement of the intermediate walls 66 forms a multiplicity of distinct, preferably similar, spaces in the frame 61.

The intermediate walls 61 may comprise a draft angle, for example of about 2%. In other words, the mutually facing surfaces of two adjacent intermediate walls 66 may have a distance that deviates in the direction of demolding. The clearance angles can be obtained by machining the intermediate walls 66. This facilitates the subsequent demolding. Despite the clearance angle, the intermediate walls 66 may be considered substantially parallel to each other.

The intermediate walls 66 comprise ribs 68. The ribs 68 project from the surfaces of the intermediate walls 66. The ribs 68 project in a direction parallel to the frame 61. The ribs 68 are elongate in a substantially perpendicular direction to the frame 61, that is to say a direction of pressing. The ribs 68 have, here, a profile, in a section substantially parallel to the frame 61, in the form of a half-disk. According to one variant, the ribs 68 may have a triangular profile. The ribs 68 may be mutually equidistant along each intermediate wall 66. The ribs 68 are, here, mutually distant by about 40 millimeters. The ribs 68 extend in the direction of the thickness of the frame 61. The ribs 68 are arranged to create recesses in surfaces of the molding material upon contact with the intermediate walls 66. Similar ribs may be provided to from the facing surfaces facing each other and at least one of the elongated members 62 to 65 of the frame 61.

The press head 19 is shown in FIGS. 3A to 3D. The press head 19 comprises a support plate 71. The press head 19 comprises panels 73.

The press head 19 comprises reinforcements 75. The press head 19 comprises bearing faces 77.

The support plate 71 is of substantially rectangular shape. The support plate 71 comprises fixing means adapted to the press 21. Here, the fixing means comprise through-fixing holes 79 formed in the thickness of the support plate 71 and in the vicinity of two of its opposite edges. The support plate 71 has a thickness selected to withstand the compressive forces of the press 21, here about 3 centimeters.

Each panel 73 has a generally rectangular shape comprising two large opposite sides corresponding to the length of the panel 73 and two small opposite sides corresponding to the width of the panel 73. Each panel 73 may comprise at least one recess 74. The recess 74 is chosen to reduce the amount of material and the mass of the device, facilitate maintenance and especially cleaning, without impairing the mechanical properties of said panel 73. The panels 73 are fixed to the support plate 71. A surface of a large The side of each panel 73 is disposed facing the support plate 71. Each panel 73 is disposed in a plane substantially perpendicular to the plane of the support plate 71. The panels 73 are arranged substantially parallel to each other. The panels 73 are arranged on one face of the support plate 71. In the mounted state, said surface of the support plate 71 is opposite the mold 17.

The panels 73 have a substantially constant mutual gap. Said gap between the panels 73 is chosen to correspond to the differences between mutually intermediate walls 66 of the mold 17, here, about 40 millimeters. The thickness and the length of the panels 73 are chosen to allow penetration of the panels 73 between the intermediate walls 66 of the mold 17, in the distinct spaces of the frame 61.

A reinforcement piece 75, or cleat, is here arranged on the short sides of each panel 73. The press head 19 comprises, here, two reinforcing pieces 75. The reinforcing pieces 75 take the form of thin elongated parallelepipeds . In the assembled state, the elongate direction of each of the reinforcing pieces 75 is oriented substantially perpendicular to the planes of the panels 73. The direction of the thickness of each reinforcing piece 75 is oriented substantially parallel to the long sides of the panels 73. Each reinforcement pieces 75 are disposed against a set of short sides of the panels 73 substantially aligned with each other. The reinforcing pieces 75 may participate in maintaining the alignment of the short sides of the panels 73 and in maintaining the mutual spacing of the panels 73. Each reinforcing piece 75 is arranged at a small distance from the support plate 71 and so that their elongated dimension is substantially parallel to the support plate 71. The reinforcing pieces 75 are arranged to allow penetration of the panels 73 between the intermediate walls 66 of the mold 17, in operation. Each of the long sides of each of the panels 73, located on the opposite side to the support plate 71, are capped with a support member 77, also called "sole".

The support members 77 take the general shape of elongated parallelepipeds of small thickness. In the mounted state, the elongate direction of each of the support members 77 is oriented substantially parallel to the long sides of the panels 73. The direction of the thickness of each support member 77 is oriented substantially perpendicular to the plane of the plate support 71, that is to say substantially along the axis of the pressing. The support members 77 are substantially parallel to the support plate 71. The elongated directions of each of the support members 77 are substantially parallel to each other. Each panel 73 is capped with at least one support member 77. The support members 77 each comprise at least one bearing surface 78 oriented on the opposite side to the support plate 71. support 78 are contained, here and to the tolerances, in a single plane substantially parallel to the support plate 71. The spacing between each support member 77 is adjusted to correspond substantially to the thickness of each intermediate wall 66 of the mold 17. The support members 77 can be likened to enlargements of the thickness of the portions of the panels 73 located on the side of the long side opposite the support plate 71. Each panel 73 and the corresponding support member 77 can be a one-piece piece.

Each support member 77 comprises notches 82. The notches 82 are formed in the long sides of the support members 77. The notches 82 extend in the thickness of the support members 77. The notches 82 are arranged to be in correspondence of shape with the ribs 68 of the intermediate walls 66 of the mold 17. In operation, the bearing surfaces 78 of the support members 77 are oriented towards the mold 17. According to a variant not shown, the bearing surfaces 78 may be provided with ribs similar to the ribs 68 of the intermediate walls 66 but oriented parallel to the support plate 71. In operation, the support members 77 of the press head 19 penetrate between each intermediate wall 66 of the mold 17. Each space between the support members 77 and the intermediate walls 66 located on either side is minimized. In general, the arrangement, dimensions and arrangement of the press head 19 and the mold 17 are mutually adjusted.

As shown in FIG. 4, in operation, the press 21 provides a substantially vertical movement F3 and / or F5 and relative between the mold 17 and the press head 19. The illustrated embodiment of the press 21 comprises a system of racks 21a and gear wheels 21b. In a variant, the system of racks 21a and gear wheels 21b is replaced by a hydraulic cylinder system (s) or pneumatic system (s) known in itself, sized to apply pressures for example of the order from 100 to 200 bars.

After the conveying container 14 has poured the second mixture 11 into the mold 17, the pressing step 102 can begin. In the embodiment shown, the conveying container 14 is placed back in a remote position (displacement along F2 in FIG. 1) horizontally of the mold 17, from the right to the left in FIG. 1, for example above the plate. 15, after the second mixture 11 has fallen into the mold 17 and before the pressing 102. In a variant, the conveying container 14 can remain substantially aligned vertically with the press head 19 and the mold 17. In this variant , the conveying container 14 is arranged to allow the interaction of the press head 19 and the mold 17. This variant has the advantage of improving the descent of the second mixture 11 into the mold 17 by passing the head 19 or the mold 17 through the conveying container 14, especially when the second mixture 11 tends to adhere to the walls of the conveying container 14. The conveying container 14 can be adjusted to the head of pre In the mold 17 is disposed a conveyor 29, in the example of Figure 1 a treadmill. The conveyor 29 comprises two opposite end rollers 30a and 30b, at least one of which can be driven by a motor (not shown). The conveyor 29 comprises a closed band 34, or web. By closed band 34 is meant a strip 25 having a shape of revolution. The closed band 34 is wrapped around the two rollers 30a and 30b. The closed band 34 comprises a flexible material, for example an elastomer of small thickness and low compressibility. The closed band 34 includes an upper strand 34a and a lower strand 34b. The conveyor 29 comprises the support plate 22. The support plate 22 comprises a bearing surface capable of mechanically supporting the pressing 102. Under the upper strand 34a of the conveyor 29 is disposed the support plate 22. The Support plate 22 is of surface, thickness and composition adapted to match the mold 17 and to withstand the pressing 102 applied by the press 21. The support plate 22 is stationary. In a state other than that of the pressing 102, the support plate 22 is vertically arranged to allow the closed band 34 to rotate around the rollers 30a and 30b and in particular to the upper strand 34a to move horizontally by limiting the friction. The support plate 22 is disposed near and under the upper strand 34a and facing the mold 17. The support plate 22 is located between the two strands 34a and 34b. This arrangement allows a molding 102 directly on the upper strand 34a but mechanically supported by the support plate 22 sandwiching the upper strand 34a of the conveyor belt with the mold 17. The upper strand 34a is arranged to support a vertical elastic movement on the pressing against the support plate 22 during pressing 102. The conveyor 29 closes the bottom of the mold 17 during pressing 102.

In operation, the press head 19 is at least partially inserted in the mold 17. The press 21 applies a force tending to push the press head 19 into the mold 17. The press head 19 slides in the mold 17. Here, the press head 19 undergoes a displacement F3 from top to bottom in the mold 17. The mold 17 is substantially stationary. The mold 17 is located above the conveyor 29, in front of the support plate 22. The mold 17 can be in contact with the upper strand 34a of the closed band 34 of the conveyor 29. The press head 19 is lowered to The displacement ensures a controlled compression of the second mixture 11 disposed in the mold 17, between the press head 19 on the one hand, and more particularly by the bearing surfaces 78 of the support members 77 and by the upper strand 34a of the conveyor 29 located opposite, supported mechanically by the support plate 22, on the other hand. The second mixture 11 is blocked in a first horizontal direction between the intermediate walls 66 or between an intermediate wall 66 and the front element 64 or the rear element 65. The second mixture 11 is blocked in a second horizontal direction, perpendicular to the first, between the left side members 62 and right 63. The second mixture 11 is compressed between the bearing surface 78 and the bearing plate 22. The bearing plate 22 is here covered with the upper strand 34a belonging to the conveyor 29.

According to an alternative embodiment or in addition, the mold 17 and the support plate 22 can undergo a vertical movement F5 towards the press head 19.

The pressing step 102 is adaptable and optimizable according to various parameters.

Among these parameters, it is possible to choose, for example, a pressing time of between 1 and 10 seconds, preferably between 1 and 5 seconds. It is possible to choose a pressing force of between 100 and 200 bar. The values given are examples and may be adapted according to the second mixture 11 and the shape and density of the products to be obtained. The pressing step 102 may comprise a heat treatment.

The pressing step 102 may comprise several substeps during which the preceding parameters vary. Between the beginning and the end of the pressing 102, the gap between the bearing surfaces 78 on the one hand and the support plate 22 on the other hand, has been reduced by a predetermined value. For example, this gap can go from about the thickness of the frame 61, here about 80 millimeters, to about half, or 40 millimeters. Said difference, after pressing, determines one of the final dimensions chosen for the second mixture 11 after pressing 102.

At the end of the pressing 102, the second mixture 11 is at least partially solidified. The solid obtained is called cake 25. The cake 25 may have a different composition of the second mixture 11, for example by the loss of a liquid phase. Said liquid phase may have been evacuated during pressing 102, for example through interstices between the parts making up the mold 17 and the press head 19. The cake 25 may have a selected particle size, for example between 0.6 and 0 , 8 micrometers. The agglomeration is controlled by choosing in particular the parameters of the pressing 102 and the composition of the binder 5. Depending on the arrangement of the mold 17, a pressing 102 can create one or more cakes 25 at a time.

In a variant, the frame 61 may comprise the support plate 22. The support plate 22 then forms a bottom of the mold 17. The pressing 102 of the second mixture 11 is then made directly on the support plate 22. conveyor 29 may comprise a closed band 34 but said closed band 34 is not caught between the support plate 22 and the second mixture 11 during pressing 102. The support plate 22 is not located under the upper strand 34a of the closed band 34 of the conveyor 29. The support plate 22 is removable. The support plate 22 is disengaged or removed from the frame 61 after the pressing 102. The uncoupling opens the lower part of the mold 17 in order to perform the demolding step 103. The support plate 22 may for example slide horizontally in the frame 61 in rails provided in the lower parts of the elongated elements 62 to 65 of the frame 61.

When the pressing phase 102 is completed, a demolding step 103 can begin. The method comprises a step of demolding 103. A further relative movement F3 or F5 of the press head 19 relative to the mold 17, pushes the cake 25 outside the frame 61 by the lower part of the mold 17. Here, during demolding 103, the press head 19 is stationary. The mold 17 is then moved vertically F5 upwards. The displacement F5 of the mold 17 vertically separates the mold 17 from the conveyor 29 and the support plate 22. Said gap F5 places the bottom of the mold 17 in the open state for demolding 103. In other words, the relative vertical displacement between the mold 17 and the press head 19 is made in the same direction at demolding 103 and pressing 102. The direction is constant. In the embodiment shown in FIG. 1, the relative displacement of the press head 19 with respect to the mold 17 is ensured by the descent F3 of the press head 19 through said immobile mold 17, during pressing 102. relative to the press head 19 relative to the mold 17 is provided by the rise F5 of the mold 17 through the press head 19 immobile, during demolding 103. The press 21 is chosen capable of ensuring these relative movements. The relative movement of the press head 19 through the mold 17 pushes the cake 25 out of the mold 17 by its lower part. There is interpenetration of the mold 17 and the press head 19.

In the variant with a removable support plate 22 fixed to the mold 17, during demolding 103, the press 21 can continue its upward translation movement (F3). The mold 17 can remain substantially stationary. At the end of demolding 103, the cake 25 can fall on the conveyor 29 or on the floor 31.

In a variant, an intermediate step between the molding 102 and the demolding 103 comprises the rise F5 of the mold 17 and the rise F4 of the press head 19. The rise F5 of the mold 17 can then be performed to open the bottom of the mold 17 , that is to say, to move it away from the support plate 22. Said rise F5 of the mold 17 does not oppose the press head 19, it can be performed by a limited power system. The extraction of the cake 25 as such is then carried out subsequently by a descent F3 of the press head 19 through the mold 17. This variant makes it possible to associate a press with the press head 19 on the one hand and a press on the other. means of vertical displacement to the mold 17 on the other hand. The mold 17 can be locked vertically during the extraction of the cake 25.

In a variant, the pressing 102 and the demolding 103 may be performed by two separate press heads and vertical axis distinct. The mold 17 moving at least horizontally to align successively with one and the other of the two press heads. This variant has the advantage of separating the function of each of the press heads and to associate therewith appropriate power presses.

The cake 25 is then demolded on the conveyor 29. The demolding step 103 comprises the extraction of the cake 25 from the bottom of the mold 17. As represented in FIG. 5, the cake 25 here takes the form of several bars 25a. each having a complementary shape of the spaces between the mold 17, the press head 19 and the support plate 22, during the pressing 102. In a cycle of steps, one can create as many bars 25a as separate spaces in the mold 17. The cake 25 and / or the bars 25a take complementary shapes of the spaces between the mold 17 and the press head 19 during the pressing 102.

The bars 25a or bars take the form of elongated parallelepipeds of substantially rectangular section. The intermediate walls 66 being substantially parallel to each other, they form cakes 25 of substantially parallelepiped shape. At least one, here two, face (s) along the length of each chip bar 25a comprises grooves 81, or pre-cracking slot. The grooves 81 are of complementary shape to the ribs of the mold 17 and in particular to the ribs 68 of the intermediate walls 66. The ribs 68 are arranged to form grooves 81 capable of initiating the rupture of the webs 25a into several portions of chipboard 33 The sintered portions 33 are shown in FIG. 6. The arrangement of the grooves 81 makes it possible to choose how the cake 25, here the bars 25a, can be divisible. The grooves 81 may form selected weak points. Here, the sinter portions 33 are substantially similar and can be normalized. Here, the sinter portions 33 have a generally cubic overall shape of edges of about 40 millimeters.

At the end of demolding 103, the cake 25 is on the upper strand 34a of the conveyor 29. The conveyor 29 can then be activated to take the cake 25 (or the strips 25a) to an output included in the device. Here, the upper strand 34a of the closed band 34 of the conveyor is driven by the rollers 30a and 30b, said upper strand 34a moves the cake 25 at least horizontally to the vicinity of one of the rollers 30b at the output of the device. The cake 25 is ejected from the conveyor 29 and starts a fall. The cake 25 can fall directly on the ground 31, or on a solid support. The subsequent mechanical impact of the drop of the cake 25 can be achieved with the floor 31. Said mechanical impact can cause a planned initiation of breaking cake 25. In other words, the device comprises an outlet capable of free falling a cake 25 The outlet is arranged so that the end of the fall causes breakage of the cake 25 in agglomerated portions 33. For example, the height of fall may be greater than about 1 meter. Said rupture can be chosen by the arrangement of the mold 17 and the press head 19, in particular as a function of the ribs being at the origin of the grooves 81. The cake 25 or the bars 25a can be cut into chipboard portions 33 The demolding 103 comprises the falling of the cake 25, the end of the fall causing the breaking of the cake 25 in chip portions 33. The sinter portions 33 and / or the bars 25a can be stored in a suitable container 35. The container 35 may be, for example, a bag.

According to a variant, after demolding 103, the shrinkage and / or vibration effect, for example during transport on the conveyor 29, may be sufficient to initiate the breaking of the cakes 25 into agglomerated portion 33.

The press 21 reverses its movement to replace the press head 19 and the mold 17 in their respective initial states. In the mode shown in Figure 1, the press head 19 is raised (according to F4) and the mold 17 is down (according to F5). The device is able to restart a pressing cycle 102 and demolding 103.

The cake 25 and / or agglomerate portions 33 may undergo a ripening period, e.g., about 24 hours. The ripening period comprises storage allowing the binder 3 to act and fix the structure of the cake 25 and / or of the agglomerate portion 33. The ripening allows the cakes 25 to harden.

The method of aggregation of dust and / or sludge comprising metals provides a product having a structure and composition suitable for subsequent treatment. The subsequent treatment may consist of a melting of the agglomerates or portions of agglomerate according to methods known per se. Since the process is inexpensive, the profitability of the reprocessing of waste from metallurgical industries can be improved. The process makes it possible to ensure homogeneity and / or standardization of the final agglomerated product. The possibility of significant modulation of the pressing time makes it possible to adapt the process to various compositions of the first mixture and to various desired structures. The device used for the process is readily adaptable to later metal recovery processes. The Applicant has particularly noted that the particle size of said agglomerates was parameterizable by adapting the composition and the amount of binder, the structure of the mold and the press head as well as the strength and duration of the pressing and optionally the treatment temperature.

The device allows the transformation of dust or sludge into agglomerates whose composition and structure allow a subsequent treatment rejecting gases whose toxicity is reduced. This can include meeting ecology standards in many countries. The Applicant has in particular measured a reduction of at least 80% of the carbon dioxide emissions compared with the usual techniques. The products obtained are therefore adaptable to the techniques used to recover metals while reducing the adverse ecological impact of the entire recycling process.

The invention is not limited to the examples of methods and apparatus described above, only by way of example, but encompasses all the variants that can be envisaged by those skilled in the art within the scope of the present claims. -after.

Claims (18)

REVENDICATIONS1. A process for agglomerating a mixture (11) comprising metallic dusts and a binder (3), comprising a pressing step (102) of the mixture (11), characterized in that the pressing (102) comprises pressing by a press head (19) in a mold (17) provided with a frame (61) and intermediate walls (66) oriented substantially parallel to the direction of the thickness of the frame (61) and provided with ribs (68) in projections in a direction in the plane of the frame (61) and elongated in a direction substantially parallel to the direction of the thickness of the frame (61), the mold (17) being configured to form at least one cake (25), said ribs (68) forming grooves (81) in said cake (25) so as to render said cake (25) breakable into chipboard portions (33). 2. The method of claim 1, wherein the pressing step is preceded by a filling of the mold (17) by the top of the mold (17). 3. Method according to one of claims 1 and 2, wherein the bottom of the mold (17) is closed during pressing (102). 4. The method of claim 3, wherein the closure comprises the formation of a bearing surface adapted to mechanically support the pressing (102). The method of one of claims 1 to 4, further comprising a demolding step (103), said demolding (103) comprising extracting the cake (25) from the bottom of the mold (17). 6. Method according to one of claims 1 to 5, wherein the binder (3) is hydraulic and inorganic. 30 7. Method according to one of claims 1 to 6, wherein the intermediate walls (66) are substantially parallel to each other and form cakes (25) of substantially parallelepiped shape. 8. Method according to one of claims 1 to 7, wherein a relative displacement of the press head (19) relative to the mold (17) is provided by the descent (F3) of the press head (19) to through said mold (17) during the pressing (102) and then by the rise (F5) of said mold (17) through the press head (19) during demolding (103). 9. Apparatus for implementing the method according to claim 1 comprising: a mold (17) provided with a frame (61) and intermediate walls (66) oriented substantially parallel to the thickness of the frame (61) and equipped with ribs (68) projecting in a direction in the plane of the frame (61) and elongated in a direction substantially parallel to the direction of the thickness of the frame (61), and a press head (19) arranged complementarily to said mold (17) to allow interpenetration of said mold (17) and said press head (19). 10. Device according to claim 9 wherein the top of the mold (17) is open during filling by the mixture (11). 11. Device according to one of claims 9 and 10 further comprising a conveyor (29) adapted to close the bottom of the mold (17) during pressing (102). 12. Device according to claim 11, wherein the conveyor (29) comprises a support plate (22) adapted to mechanically support the pressing (102). 13. Device according to one of claims 9 to 12 wherein the bottom of the mold (17) is open during demolding (103) .25 14. Device according to one of claims 9 to 13, further comprising an outlet capable of free falling a cake (25) from the demolding (103), the end of said fall being able to cause breaking of the cake ( 25) in chipboard portions (33). 15. Device according to one of claims 9 to 14 wherein the intermediate walls (66) are substantially parallel to each other and able to form cakes (25) of substantially parallelepiped shape. 16. Device according to one of claims 9 to 15, further comprising a press (21) capable of imposing a relative displacement of the press head (19) relative to the mold (17), capable of ensuring the descent (F3 ) of the press head (19) through said mold (17) immobile during pressing (102) and then to ensure the rise (F5) of said mold (17) through the press head (19) immobile during demolding (103). 17. The separable cake obtained by the method of claim 1 comprising grooves (81) in at least one of its surfaces and arranged to be initiators of rupture of said cake (25) chip portions (33). 18. Cake according to claim 17 in the form of strips (25a) breakable into 20 agglomerated portions (33) substantially similar to each other and substantially cubic.