NL2037198B1

NL2037198B1 - Method and apparatus for separating particles of a particle stream of crushed concrete

Info

Publication number: NL2037198B1
Application number: NL2037198A
Authority: NL
Inventors: Petrus Maria Van De Winckel Thijs; Daniel Patrick Petithuguenin Thomas
Original assignee: C2Ca Tech B V
Priority date: 2024-03-07
Filing date: 2024-03-07
Publication date: 2025-09-22
Also published as: WO2025188186A8; WO2025188186A1

Abstract

Title: Method and apparatus for separating particles of a particle stream of crushed concrete Abstract A method and apparatus for separating particles of a particle stream of crushed concrete, in particular end-of-life concrete, is disclosed. The apparatus comprises a first actor arranged to act on particles of the stream to make the particles follow primary ﬂight trajectories and a primary ﬂight space arranged adjacent the actor for particles that have been acted on to follow primary ﬂight trajectories therethrough so as to effect separation of the particles, as well as at least one further actor arranged to act on particles to make the particles of the second group follow secondary ﬂight trajectories, and a secondary ﬂight space adjacent the second discharge for discharged particles of the second group to follow secondary ﬂight trajectories therethrough to effect further separation of the particles of the second group.

Description

P136275NL00

Title: Method and apparatus for separating particles of a particle stream of crushed concrete

The invention generally relates to separating particles of a particle stream of crushed concrete, in particular crushed end of life concrete.

Concrete is one of the most widely used construction materials.

Main constituents of concrete are coarse aggregates, e.g. gravel, used as means to provide compressive strength, fine aggregates, e.g. sand, used as means to fill the spaces between the coarse aggregates, as well as cement and water, used as means to bind the aggregates. In the binding process, cement particles, e.g. cement paste or cement powder, react with the water to form cement hydrates that act as binder.

For the production of new concrete, typically fresh water, and virgin aggregate and virgin cement particles are used. Making these concrete constituents available puts a significant burden on the environment. The production of virgin cement particles alone is responsible for about 8-9% of the global CO: emissions.

Due to the wide use of concrete, end of life concrete is among the most abundant waste streams. Recycling of end of life concrete can reduce the CO: footprint of new concrete when its constituents are recovered and turned into a product to at least partially replace virgin concrete constituents. Recycling may take place by crushing concrete to break it up into particles, and to separate the particles into fractions that can be used to at least partially replace the virgin cement , the virgin fine aggregates and the virgin coarse aggregates used for concrete, e.g. by crushing the concrete and sieving the stream of crushed particles.

However, recycling end of life concrete is a bulk process that needs to be performed at low costs. This makes it very challenging to generate particles that can serve as (partial) replacement for the virgin constituents.

Firstly, the types of particles used as coarse aggregates and fine aggregates can vary greatly, and the recovery process for end of life concrete is in practice typically not sophisticated enough to yield a stream of crushed concrete of constant constituency. In addition, the recovery process of end of life concrete 1s typically not sophisticated enough to allow for constant humidity of the stream of crushed concrete. Humidity of the stream of crushed concrete may e.g. vary with weather conditions due to a need to collect and store end of life concrete outdoors. As increases in humidity increase stickiness of cement rich particles in the stream, the process of sieving itself can become a challenge, and the fine and course aggregates get contaminated with cement rich particles. In practice, reuse of cement rich particles is very limited, and -due to the contamination with cement rich particles- reuse of aggregate particles in concrete is very limited.

The invention aims to at least partially alleviate the above mentioned drawbacks. In particular, the invention aims to provide a method and apparatus for separating particles of a particle stream of crushed concrete, with which particles can be generated that are more suitable as (partial) replacement for the virgin constituents of concrete, either directly or after further processing, and/or with which particles of a particle stream of crushed concrete particles can be separated into fractions of particles relatively easily and/or cost effectively.

Thereto the invention provides for a separation apparatus for separating particles of a particle stream of crushed concrete, in particular end-of-life concrete, the particle stream including cement rich particles, fine aggregate particles and coarse aggregate particles, the apparatus comprising: - a first actor arranged to act on particles of the stream to make the particles follow primary flight trajectories, - a primary flight space arranged adjacent the actor for particles that have been acted on to follow primary flight trajectories therethrough so as to effect separation of the particles, the primary flight space including:

- a first collection zone arranged relatively near the first actor to receive a first group of particles that are made to follow primary flight trajectories to landing locations at relatively short distances from the actor, and

- a second collection zone arranged relatively further away from the first actor to receive a second group of particles that are made to follow primary flight trajectories to landing locations at relatively long distances from the first actor, wherein

- the first collection zone is provided with a first discharge arranged to discharge particles of the first group of particles, wherein

- the second collection zone is provided with a second discharge arranged to discharge particles of the second group of particles, and wherein

- the first group of particles is relatively rich in cement rich particles, and is relatively poor in fine aggregate particles and in coarse aggregate particles, the separation apparatus further including:

- at least one further actor arranged to act on particles of the second group to make the particles of the second group follow secondary flight trajectories,

- a secondary flight space adjacent the second discharge for discharged particles of the second group to follow secondary flight trajectories therethrough to effect further separation of the particles of the second group, the secondary flight space including

- a first further collection zone arranged relatively near the further actor to receive a first subgroup of particles that are made to follow secondary flight trajectories to landing locations at relatively short distances from the further actor, and

- a second further collection zone arranged relatively further away from the further actor to receive a second subgroup of particles that are made to follow secondary flight trajectories to landing locations at relatively long distances from the further actor, wherein - the first further collection zone is provided with a first subdischarge arranged to discharge the first subgroup of particles, wherein - the second further collection zone is provided with a second subdischarge arranged to discharge particles of the second subgroup of particles, and wherein - the first or the second subgroup of particles is relatively rich in coarse aggregate particles, and relatively poor in cement rich particles and fine aggregate particles.

By acting on the particles to follow first and second flight trajectories to effect separation, a first flight separation step can be focused to yield a first group of particles with cement rich particles that are suitable to be used as (partial) replacement for virgin cement particles, while the second flight separation step can be focused to yield from a second group of particles a subgroup with coarse aggregates that are relatively free of cement rich particles and that are more suitable to be used as (partial) replacement for virgin coarse aggregates. The particle stream with coarse aggregates can thus be cleaned of cement rich particles twice, while the cement rich particles themselves can also be concentrated for reuse. The other subgroup of particles can be focused to yield particles that are suitable to be used as (partial) replacement for fine aggregates. The second flight separation step can be used to increase spatial distribution of the particles of the second group, so as to facilitate separation. In particular, by both throwing and blowing the particles of the second group, the particles may be prevented from hindering each other, and may be more readily available to be acted on.

Based on their size and/or density, particles may thus be classified into a) a fraction of relatively large and heavy particles that is relatively rich in coarse aggregates and that 1s suitable to be used as or suitable to yield particles as (partial) replacement of virgin coarse aggregates, and b) a fraction of relatively small and light particles that is relatively rich in cement particles that is suitable to be used as or suitable to yield particles as (partial) replacement of virgin cement particles, and ¢) an intermediate 5 fraction of particles that is relatively rich in fine aggregates and that is suitable to be used as or suitable to yield particles as (partial) replacement of virgin fine aggregates. The first group of particles that is relatively rich in cement particles may e.g. include a majority of cement rich particles that are typically smaller than 1 mm, and that comprises both cement particles that are free and that are e.g. 10-40 um and cement particles that are bound with very fine aggregates to a diameter of typically 1 mm or smaller, as well as a minority of other particles, e.g. particles smaller than 1 mm that are not cement rich or that are larger than 1 mm. The first or second subgroup of particles that is relatively rich in coarse aggregate particles, and that is relatively poor in cement rich particles and fine aggregate particles may e.g. include a majority of gravel particles that are typically larger than 4 mm, as well as a minority of other particles, e.g. compound particles of sand and cement particles that are larger than 4 mm, and particles smaller than 4 mm, e.g. sand particles and cement particles that stick to the gravel particles. The other subgroup with the intermediate fraction of particles that 1s relatively rich in fine aggregates may e.g. include a majority of sand particles typically sized between 1 and 4 mm, as well as a minority of other particles, e.g. particles sized between 1 and 4 mm that are not sand, and particles that are larger than 4 mm or smaller than 1 mm.

For ancillary determination of the terms aggregates, fine and coarse aggregates, gravel, sand, grading and size determination of particles, reference may be made to NEN-EN 12620+A1 (en).

The first actor may e.g. be embodied as a conveyor with a free end adjacent the primary flight space. The separation device may include further components, e.g. an infeed that is arranged to feed particles of the stream to the first actor so as to be acted on. As relatively large and heavy particles fly further away from the further actor if the actor powers flight by providing impulse only, the second subgroup of particles is the subgroup that 1s relatively rich in coarse aggregate particles, and relatively poor in cement rich particles and fine aggregate particles.

For particularly efficient separation, the first actor may include or be embodied as a rotor, which rotor is arranged to act on particles by impacting on particles of the stream to make the particles follow primary flight trajectories. Such rotor may advantageously impact on the particles to break

H bonds, and to liberate cement rich particles from aggregates, and to break up conglomerates of cement rich particles and coarse and/or fine aggregate particles. Such rotor may be arranged to rotate with an adjustable rotor speed, and may be provided with substantially radially extending hitting plates to act on the particles. The rotor may e.g. be embodied as a drum with hitting plates disposed about its circumference. The infeed may be arranged to feed particles of the stream to the hitting plates of the rotor, e.g. as a curtain of falling particles.

To enhance efficiency of separation in the primary flight space, at least the primary flight space may be provided with secondary impact surfaces for particles to bounce off during the primary flight trajectory.

Secondary impact further liberates cement from aggregates, and breaks up conglomerates further. The secondary impact surface may extend along the first and or second collection zones, e.g. above and/or adjacent the first and/or second collection zones. At least some of the impact surfaces may form part of a housing of the separation device, e.g. a roof and/or side walls of a housing portion that at least partially encloses the primary flight space.

To effect or enhance efficient separation in the secondary flight space, the further actor may be or include a blower arranged to blow particles out from the second group as a blown out particle subgroup through the secondary flight space to a blown out particle subdischarge. The blown out particle subdischarge may be separate from the first or second subdischarge, but may alternatively be included in either the first or the second subdischarge, preferably the first subdischarge. The blown out subgroup of particles in the blown out particles discharge may be relatively rich in cement rich particles compared to the remaining particles of the second subgroup. The blown out particle subgroup may include a majority of particles sized between 1 and 4 mm, as well as a minority of other particles, e.g. particles sized between 1 and 4 mm that are not sand, and particles that are smaller than 1 mm or larger than 4 mm.

Compared to the first group of particles, the blown out particle subgroup may be relatively rich in cement rich particles of 1-2 mm, and may be relatively rich in and fine aggregate particles of e.g. 1-4 mm, 2-4 mm or 3- 4 mm. The blown out particle subgroup may also be relatively rich in contaminants of materials that have relatively low density compared to cement and aggregates, and may typically be relatively rich in wood, plastic and foam particles compared to the first particle group and the remaining particles of the second group. The blower may be arranged to deliver an air flow that is adjustable, e.g. in position, direction, amount of flow, and/or speed of flow.

The first particle subdischarge and/or the blown out particle discharge may include a sieve for sieving out contaminant particles. Such sieve may also be provided externally to the separation apparatus, e.g. as part of a further processing step. The sieve may be arranged to sieve out contaminant particles of relatively large size and relatively low density compared to cement and aggregate particles e.g. foam and wood. Such sieve may e.g. be a conventional sieve with a planar deck, but may also be embodied as a sieve with a 3 dimensional sieve deck. The sieve may e.g. have a maximum pass through dimension of 8-10 mm, e.g. using a screen aperture of 8-10 mm. The screen may be selective on long particles. Wood and wires can e.g. be separated when they are travelling over the sieve deck in flat position. This can e.g. be done by a first section without apertures (i.e. a blind screen deck), a relatively high angle (>10% inclination) and a low amplitude (<1 cm) to prevent long particles to be arranged in vertical position.

The blower may be arranged to blow particles out from the second group as a second subgroup of particles to follow flight paths through the secondary flight space to the second subdischarge, e.g. to pass a splitter, the remaining particles following fight paths as a first subgroup of particles through the secondary flight space to a first subdischarge. the blower may be arranged as a conventional blower that blows downward against a throwing direction. In such configuration, the first subgroup of particles may be relatively rich in cement rich particles and fine aggregate particles, and the second subgroup may be relatively rich in coarse aggregate particles, and relatively poor in cement rich particles and fine aggregate particles. The blower may alternatively be arranged as a wind sifter that blows upward along a throwing direction. In such configuration the first subgroup of particles may be relatively rich in coarse aggregate particles, and relatively poor in cement rich particles and fine aggregate particles. In such wind sifter embodiment, the blower arrangement may power flight of the second group of particles. In such embodiment, flight of relatively small, relatively light and relatively flat particles (i.e. particles which have a relatively high surface area to mass ratio) is more effectively powered, and the first subgroup of particles can be the subgroup that is relatively rich in coarse aggregate particles, and relatively poor in cement rich particles and fine aggregate particles.

The further actor may e.g. be embodied as or include a rotor of the type discussed above in respect of the first actor. To effect or enhance efficient separation in the secondary flight space, the further actor be embodied as or include a conveyor with a free end adjacent the secondary flight space, which conveyor is arranged to act on the particles by conveying the particles of the second group to the free end and by throwing the particles off the free end to make the particles follow secondary flight trajectories through the secondary flight space. The conveyor may be arranged so that its conveying surface forms at least part of the second collection zone. The free end of the conveyor may form the second discharge.

The conveyor to the second discharge may be embodied as a second conveyor, e.g. where the second conveyor is arranged in the primary flight area to convey to the second discharge so that its conveying surface forms at least part of the second collection zone. The conveyor or conveyors may be provided with a moving conveying surface, e.g. a conveyor belt, but may alternatively be provided with a stationary conveying surface, e.g. a chute.

To enhance efficiency of separation in the secondary flight space the further actor may be embodied as or include a splitter arranged in the secondary flight space to act on the particles of the second group by splitting them into a first split off subgroup of particles that follow secondary flight trajectories to a first split off particle discharge located at a first distance from the free end, and a second split off subgroup of particles that follow secondary flight trajectories to a second split off particle discharge at a second, relatively further distance from the free end. The first split off particle discharge may be a separate discharge, but may also form or be included in the first subdischarge. The second split off particle discharge may be a separate discharge, but may also form or be included in the second subdischarge. The splitter may e.g. be embodied as an upright plate, and may be provided with a rotating cylinder. The tip of the plate may e.g. be arranged with a roll to prevent buildup of particles. As an alternative, the splitter may be embodied as a separation roll. At least a tip of the main splitter may be adjustable, e.g. in position, height, distance to the further actor and/or angle relative to the stream of particles of the second group.

The adjustment of the splitter may be automated, e.g. based on a measurement in the field by a inline quality control of parameters including one or more of humidity, particle size distribution and/or contamination of the subgroup of particles that is relatively rich in coarse aggregates (RCA).

The particles of the second split off sub group may have an average size larger than particles of the first split off subgroup.

The second discharge may include an auxiliary splitter that is located at a distance from the free end that is smaller than the distance of the main splitter to the free end. The auxiliary splitter may split particles that are blown out by the blower from the first split off particle subgroup in the first further collection zone off as a blown out particle subgroup, and may divide the first subdischarge into a blown out particle discharge and a first split off particle discharge.

The separation apparatus may comprise a first conveyor arranged so that its conveying surface forms at least part of the first collection zone, and/or a second conveyor arranged so that its conveying surface forms at least part of the second collection zone. The secondary conveyor may provide for a landing impact surface that further liberates cement rich particles from aggregate particles and that collect and discharges cement rich particles and aggregate particles while being interspaced from each other.

This facilitates separation in the secondary flight area. The conveying surface of the first conveyor may form the first collection zone, and/or the conveying surface of the second conveyor may form the second collection zone. The first conveyor may be arranged to convey particles of the first group to the first discharge, and the second conveyor may be arranged to convey particles of the second group to the second discharge. The conveying surface of the first conveyor may be arranged to extend to a distal end of the first landing zone relative to the rotor, the conveying surface of the second conveyor may be arranged to extend from a proximal end of the second landing zone relative to the rotor, and the distal and proximal ends of the respective first and second conveyors may be adjacently arranged at a point of abutment. The first actor and the point of abutment may be movably arranged relative to each other, so as to allow adjustment of the distance between the first actor and the point of abutment. The conveyors, and in particular the second conveyor, may be arranged to have an adjustable conveying speed, e.g. to ensure the presence of sufficient interspace between particles collected on the conveying surface of the conveyor, and/or the impulse of particles thrown on the free end of the conveyor.

The separation apparatus may further comprise a controller arranged to control at least one of a position and/or rate of an infeed, a position and/or rotational speed of rotor, a conveying speed and/or angle of inclination of a first conveyor, a conveying speed and/or angle of inclination of a second conveyor, a distance between the first actor and a point of abutment between a first landing surface and a second landing surface, a position, direction, amount of flow, speed and/or of flow of a blower, a position, height, and/or angle of a splitter in relation to a composition of the particles stream.

This way, the separation apparatus can during operation be controlled to adjust for variations in humidity and constitution of the stream of crushed concrete particles, e.g. to ensure a consistent composition of the particles in the particle groups. The adjustment by the controller may e.g. be based on a measurement in the field of one or more control parameters using one or more of an inline sensor, e.g. a laser scanner and/or a humidity sensor. Such control of parameters may include one or more of humidity, particle size distribution, contamination or any other parameter relating to properties of the particles. Such sensor(s) may be located at one or more locations in the separation apparatus, e.g. in the infeed and/or discharge(s).

The invention further relates to a method for separating particles of a particle stream of crushed concrete, in particular end-of-life concrete, in particular using a separation apparatus including features as discussed above, the particle stream including cement rich particles, fine aggregate particles and coarse aggregate particles, the method comprising:

- acting on particles of the stream with a first actor to make the particles follow primary flight trajectories so as to effect separation of the particles, - collecting a first group of particles that are made to follow primary flight trajectories to landing locations at relatively short distances from the first actor, - collecting a second group of particles that are made to follow primary flight trajectories to landing locations at relatively long distances from the first actor, - the first group of particles being relatively rich in cement rich particles, and being relatively poor in fine aggregate particles and in coarse aggregate particles, - acting on particles of the second group with a further actor to make the particles of the second group follow secondary flight trajectories to effect further separation of the particles of the second group, - collecting and discharging a first subgroup of particles that are made to follow secondary flight trajectories to landing locations at relatively short distances from the further actor, and - collecting and discharging a second subgroup of particles that are made to follow secondary flight trajectories to landing locations at relatively long distances from the further actor, wherein the first or the second subgroup of particles is relatively rich in coarse aggregate particles, and relatively poor in cement rich particles and fine aggregate particles.

In particular, the second subgroup of particles may be relatively rich in coarse aggregate particles, and relatively poor in cement rich particles and fine aggregate particles. The first actor may act on particles by impacting on particles of the stream to make the particles follow primary flight trajectories. The further actor may blow particles out from the second group as a blown out particle subgroup. The further actor may act on the particles of the second group by splitting them into a first split off subgroup of particles that follow secondary flight trajectories to a first split off particle discharge at a first distance from the first actor, and a second split off subgroup of particles that follow secondary flight trajectories to a second split off particle discharge at a second, relatively further distance from the further actor.

In the separation apparatus or method as discussed above, the first group of particles is relatively rich in cement particles, in particular in cement hydrates. At least 35 wt% may be cement hydrates, preferably at least 67%. At least 90% of the cement rich particles may be smaller than 1 mm or 2 mm in maximum dimension, and may e.g. be included in a range of maximum dimension e.g. 0-2 mm.

The second subgroup of the second group of particles may mainly include coarse aggregates. At least 70 wt%, preferably at least 90 wt%, of the particles of the second subgroup may e.g. be coarse aggregate particles and/or at least 90% of the coarse aggregate particles may be larger than 4 mm in maximum dimension, and may e.g. be included in a range of maximum dimension of e.g. 4-16 mm or 4-22 mm. The second subgroup of the second group of particles may be substantially free of cement rich particles, e.g. at most 10% of the particles may be cement rich particles. The second subgroup of particles may e.g. have a maximum a water absorption of 5%, but preferably a water absorption of less than 3%.

The first subgroup of the second group of particles may mainly include cement rich particles and fine aggregates. At least 50% of the particles in the second group may e.g. be fine aggregate particles and/or at least 95% of the fine aggregate particles may be smaller than 5,6 mm, and 100% may be smaller than 8 mm, preferably 0,25-5,6 mm for coarse sand, and 0,063-4 mm for fine sand.

The invention also relates to coarse concrete aggregate separated from a particle stream of crushed concrete, in particular end-of-life concrete,

in particular using a separation apparatus or method of separation according to any of the preceding claims, the separated coarse concrete aggregate comprising particles of which at least 80wt% are coarse aggregate particles, and/or of which at least 85% of the coarse aggregate particles are larger than 4 mm, 95% larger than 2 mm, 99% larger than 1 mm e.g. 4-16 mm, the separated coarse concrete being substantially free of cement rich particles. Preferably, a maximum of 10% of the coarse aggregate particles is larger than 16 mm. The lightweight organic content in the coarse aggregate particles should preferably not exceed 0,1 wt%, more preferably 0,05 wt% or less.

The above aspects of the invention individually alleviate disadvantages, and in combination can alleviate disadvantages further. The above aspects of the invention together form an invention, but may each individually also be seen as inventions on their own.

The invention will further be elucidated on the basis of exemplary embodiments which are represented in the drawings. The exemplary embodiments are given by way of non-limitative illustrations of the invention.

In the drawings:

Fig. 1 shows a schematic overview of a first embodiment of a separation apparatus,

Fig. 2 shows a detail of Fig. 1, and

Fig. 3 shows a schematic overview of a second embodiment of a separation apparatus.

Across the drawings of the exemplary embodiments, identical or corresponding parts have been provided with the same reference numerals.

Fig. 1 shows an overview of an exemplary embodiment of a separation apparatus 1 for separating particles of a particle stream 2 of crushed concrete that has e.g. been sieved through a pass through sieve of 16 mm in a preprocessing step.

The crushed concrete has been obtained from end-of-life concrete waste. Such end-of-life concrete waste has preferably been collected separate from other demolition waste, and preferably has been collected from demolition of bridge parts or building skeletons (e.g. floors and pillars).

The crushing process is preferably arranged to reduce the amount of particles in the particle stream that are conglomerates of aggregates and cement, e.g. by using a vibratory cone crusher and/or by feeding a portion of the stream of particles back to the crusher.

The particle stream 2 includes cement rich particles 2a, typically having maximum dimensions in the range of 0-2, e.g. 0-1 mm, fine aggregates 2b, typically having maximum dimensions ranging between 63 micron and 5,6 mm, e.g. 2-4 mm, and coarse aggregates 2c, typically having maximum dimensions in the range of 4-16mm. The cement rich particles in crushed end-of-life concrete are typically cement hydrates. The cement rich particles include both cement particles that are free and that are e.g. 10-40 um in dimension, and cement particles that are bound with very fine aggregates to a diameter of typically 1 mm or smaller. Cement rich particles typically include hydration products such as calcium silicate/ aluminate hydrates (CSH/ CAH/ CASH), CaCO3, unreacted cement particles and aggregate particles typically include Quartz S102.

The apparatus 1 includes a first actor 3 that acts on particles of the stream 2 to make the particles 2 follow primary flight trajectories 4 through a primary flight space 8. The first actor 3 1s embodied as a rotor 3. The rotor 3 comprises a drum 5 with radially extending hitting plates 6 disposed around its circumference. The rotor 3 is arranged to rotate with an adjustable rotor speed. The particles 2 are fed as a curtain c of falling particles to the rotor 3 by an infeed 7, e.g. a trough 7a with a planar chute 7b that are arranged to vibrate together. The hitting plates 6 impact particles of the stream 2 that are fed to the rotor 3, so that the particles 2a, 2b, 2c are made to follow the primary flight trajectories 4. The hitting plates

6 of the rotor 3 impact on the particles 2 to break water bonds (H bonds) between the cement rich particles 2a and the aggregates 2b, 2¢ so as to break up conglomerates of cement rich particles 2a and coarse and/or fine aggregate particles 2c, 2b, and to liberate cement rich particles 2a from aggregates 2b,2c.

The primary flight space 8 of the separation apparatus 1 comprises a first collection zone 9 and a second collection zone 10. The first collection zone 9 is arranged near the rotor 3 to receive a first group of particles 11 that are made to follow primary flight trajectories 4 to landing locations at relative short distances from the rotor 3. A first conveyor 13 is arranged in the first collection zone 9 so that its conveying surface 13a corresponds to the landing locations at relatively short distances from the rotor 3. The first conveyor 13 is provided with a first discharge 14 that is arranged to discharge particles of the first group 11 to be collected for further processing towards re-use. The first group of particles 11 is relatively rich in cement rich particles 2a, and relatively poor in fine aggregate particles 2b and in coarse aggregate particles 2c.

In the first collection zone 9 the majority of particles smaller than 1 mm 1s collected. However, the size range is not limited to 0-1 mm particles as light weight particles and elongated particles are likely to be collected in the first collection zone 9. Light weight particles tend to travel less far in the primary flight space. For elongated particles it is however likely that they are hit by the rotor 3 below their center of gravity, which will result in a particle to rotate fast around its center of gravity and travel less far in the primary flight space. As smaller particles have more surface area (surface/mass ratio) the first group of particles in the first collection zone is higher in moisture content compared to the material at the infeed or in the second collection zone 10. Due to the nature of separation the first group of particles 11 has a concentration of not only small particles (0-1 mm), but also includes organic particles (fibers, plastic, wood) and elongated particles

(plastics, wood or odd shape crushed end-of-life concrete). With respect of the composition the first group of particles one sees an increased content of hydration products such as calcium silicate/ aluminate hydrates (CSH/

CAH/ CASH), CaCO3, unreacted cement particles and decreased content of quartz S102.

The first group of particles that is relatively rich in cement particles may e.g. include a majority of cement rich particles that are typically smaller than 1 mm, and that comprises both cement particles that are free and that are e.g. 10-40 um and cement particles that are bound with very fine aggregates to a diameter of typically 1 mm or smaller, as well as a minority of other particles, e.g. particles smaller than 1 mm that are not cement rich or that are larger than 1 mm.

The second collection zone 10 is arranged further from the rotor 3 to receive a second group of particles 12 that are made to follow primary flight trajectories to landing locations at relative further distances from the rotor 3. A second conveyor 15 is arranged in the second collection zone 10 so that its conveying surface 15a corresponds to the landing locations at relatively long distances from the rotor 3. The second conveyor 15 is provided with a second discharge 16 arranged to discharge particles of the second group 12 to be collected. The second group of particles 12 is relatively poor in cement rich particles 2a, and relatively rich in fine aggregate particles 2b and in coarse aggregate particles 2c.

In the second collection zone 10 the majority of particles bigger than 1 mm are collected. As a result the typical composition of the material collected in the first collection zone 10 are particles in the size range of 1-16 mm. However the size range is not limited to 1-16 mm, as some of the fine particles (<1 mm) travel with the larger particles, either still adhering to their surface or in their slipstream. As bigger particles have less specific surface area (surface/mass ratio), the product in the first collection zone is lower in moisture content compared to the material at infeed or in collection zone 9. Due to the nature of separation the second group of particles 12 has a concentration of not only bigger particles (1-16 mm), but contains also less organic particles (fibers, plastic, wood). With respect of the composition of the second group of particles 12 one sees an increased content of quartz

S102, and a decreased content of hydration products such as calcium silicate/ aluminate hydrates (CSH/ CAH/ CASH), CaCO3, unreacted cement particles and CaO3.

The conveying surface 13a of the first conveyor 13 is arranged to extend to a distal end 13b relative to the rotor 3, and the conveying surface 15a of the second conveyor 15 is arranged to extend from a proximal end 15b relative to the rotor. The conveyors 13, 15 are arranged to have an adjustable conveying speed, e.g. to ensure the presence of sufficient interspace between particles 2 collected on the conveying surface 13a, 15a of the conveyor 13, 15, and/or the impulse of particles 2 thrown on the free end of the conveyor 13, 15.

The distal and proximal ends 13b, 15b of the respective first and second conveyors 13, 15 are adjacently arranged at a point of abutment q.

Both conveyors 13, 15 are arranged to be able to jointly move relative to the rotor 3, so that the point of abutment q is movable relative to the rotor 3.

The separation apparatus 1 includes at least one further actor 17 arranged to act on particles of the second group 12 to make the particles of the second group 12 follow a secondary flight trajectory 18 in a secondary flight space 19. The secondary flight space 19 is adjacent the second conveyor 15, and includes the second discharge 16 for discharged particles of the second group 12. The secondary flight space 19 comprises a first further collection zone 20, a second further collection zone 21, a first subdischarge 22 arranged to discharge a first subgroup of particles 23, and a second subdischarge 24 arranged to discharge a second subgroup of particles 25.

In Fig. 1 the at least one further actor 17 includes a blower 26, the second conveyor 15, a main splitter 27, and an auxiliary splitter 28. The blower 26 is arranged to deliver an air flow that can make particles 2 follow a secondary flight trajectory 18, or can influence such secondary flight trajectory 18. The delivered air flow is adjustable, e.g. in position, direction, amount of flow, and/or speed of flow. The blower 26 is arranged to blow particles out from the second group 12 as a blown out particle subgroup 26a through the secondary flight space 18 to a blown out particle subdischarge 22a. The blown out particle subdischarge 22a is included in the first subdischarge 22. The blown out subgroup of particles 26a in the blown out particles discharge 22a 1s relatively rich in cement rich particles 2a compared to the remaining particles of the second subgroup 25. The blown out particle subgroup 26a is, compared to the first group of particles 11, relatively rich in cement rich particles 2a having a maximum dimension of 1-2 mm. The blown out particle subgroup 26a is also relatively rich in contaminants of materials that have relatively low density compared to cement 2a and aggregates 2b, 2c, and is typically relatively rich in wood and foam particles compared to the first particle group 11 and the remaining particles of the second group 12. The particles brought into the secondary flight space will travel through an air flow provided by a blower 26. The aim of the separation in the secondary flight space 18 in this embodiment is to separate fine from coarse aggregate, for which the typical cut point is defined at 4 mm. However a different separation point may be used to generate other size fractions when desired.

In the secondary flight space particles with a very high specific surface area and density close to 1 kg/liter will be affected the most by the air flow provided by the blower 26, and be concentrated in the first particle subdischarge 22a. Particles with a high specific surface area can be defined as small particles (<1 mm), flat broken aggregates, wood and plastics (in most cases elongated parts (wooden sticks) or plastic foils which travelled in the slipstream to second collection zone 10. As a result particles which are least affected by the blower 26 end up in the second subgroup of particles

25. The majority of these particles is in the size range of 4-16 mm. The second subgroup of particles is typically free of light weight particles.

Particles in the second subgroup 25 are typically coarse aggregates, and the particles in the second subgroup 25 are comparable in the base composition to virgin coarse aggregate, e.g. river gravel that is rich in S102.

The particles of the blown out particle subgroup 26a may be combined with the particles of the first particle group 11 for further processing. Both of these groups 11, 26a are relatively rich in smaller cement rich particles 2a, and may either alone or combined be used as additives or (partial) replacement to the cement fraction for new concrete. These cement rich particles 2a may be reactivated in a second step.

The second conveyor 15 includes a free end 15¢ adjacent to the secondary flight space 19 and is arranged to act on the particles of the second group 12 by conveying the particles of the second group 12 to the free end 15c and by throwing the particles 2 off the free end 15c to make the particles 2 follow a secondary flight trajectory 18 through the secondary flight space 19.

A main splitter 27 is arranged as a further actor 17 in the secondary flight space 19 to act on the particles of the second group 12 that are thrown of the free end 15c by the second conveyor 15. The splitter 27 splits the particles 2 travelling through the secondary flight space 19 into a first split off subgroup of particles 23 that follow secondary flight trajectories 18 to a first split off particle subdischarge 22b located at a first distance from the free end 15c of the second conveyor 15, and a second split off subgroup of particles 25 that follow secondary flight trajectories 18 to a second split off particle subdischarge 24a at a second, relatively further distance from the free end 15c. In the embodiment of Fig. 1, the first split off particle subdischarge 22b is a separate part of the first subdischarge 22, and the second split off particle discharge 244 forms the second subdischarge 24.

Due to the tendency of particles 2 of comparable density to travel further with increasing size, aggregate particles of the second split off sub group 25 have an average size larger than particles of the first split off subgroup 23. A tip 27a of the main splitter 27 is adjustable in height relative to the free end 15c of the second conveyor 15. By adjusting the height of the main splitter 27 and/or the speed of the second conveyor 15, the relative composition of the particles between the first and second split off subgroup 23, 25 can be controlled. In particular, by increasing the height of the tip 27a of the splitter 27 and/or lowering the speed of the second conveyor 15, the average size of aggregate particles 2 in the second split off subgroup 25 can be increased relative to the average size of particles 2 in the first split off subgroup 23. In particular, the second split off group of particles 25 can then contain relatively large particles 2 that have been cleaned of cement rich particles 2a twice during a flight trajectory, and can thus contain relatively many coarse aggregates 2c that are relatively free of cement rich particles 2a and that are suitable to be used as (partial) replacement for virgin coarse aggregates in new concrete, i.e. recycled coarse aggregates (RCA). RCA typically has a size range of 4-16 mm and the composition is close to the original composition of the primary (virgin) aggregate used, e.g. crushed stone or “river gravel” that is high in SiO2.

The second discharge 16 includes an auxiliary splitter 28 that is located at a distance from the free end 15c that is smaller than the distance of the main splitter 27 to the free end 15c. The auxiliary splitter 28 splits particles 2 that are blown out by the blower 26 from the first split off particle subgroup in the first further collection zone 20 off as a blown out particle subgroup 26a, and divides the first subdischarge 22 into a blown out particle subdischarge 22a and a first split off particle subdischarge 22b.

In Fig. 1 the first subdischarge 22 is relatively poor in coarse aggregate particles 2c and relatively rich in cement rich particles 2a and fine aggregate particles 2b. A deck sieve 29 is provided to filter out particles

2 larger than a passthrough dimension of 8 mm to further separate the large particles 2 from the smaller particles 2.

The second further collection zone 21 is arranged relatively further away from the further actor 17 to receive the second subgroup of particles 25 that follow a secondary flight trajectory 18 with a landing location that is relatively further away from the further actor 17. The second further collection zone 21 is provided with a second subdischarge 24 of particles. In

Fig. 1 this subdischarge of particles 24 is relatively rich in coarse aggregates 2c and relatively poor in cement rich particles 2a and fine aggregate particles 2b.

A controller 34 is arranged to control the rate of infeed 7, the rotational speed of the rotor 3, the conveying speed of the first conveyor 13, the conveying speed of the second conveyor 15, the distance between the rotor 3 and a point of abutment q between the first landing surface and the second landing surface, the amount of air flow of the blower 26, and the height of the splitter 27, during operation.

In use, the separation apparatus 1 separates particles of a particle stream 2 of crushed end-of-life concrete. The particle stream 2 includes cement rich particles 2a, fine aggregate particles 2b and coarse aggregate particles 2c.

The separation apparatus 1 acts upon particles of the stream 2 with a rotor 3 to make the particles 2 follow primary flight trajectories 4 so as to effect separation of the particles 2. Separation is shown by the different primary flight trajectories 4 of the particles 2, resulting in a first group of particles 11 and a second group of particles 12.

A first group of particles 11 that are made to follow primary flight trajectories 4 to landing locations at relatively short distances from the first actor 3 is collected on the first conveyor 13, and is conveyed to the first discharge 14. The first group of particles 11 in Fig. 1 is relatively rich in cement rich particles 2a, and is relatively poor in fine aggregate particles 2b and in coarse aggregate particles 2c.

A second group of particles 12 that are made to follow primary flight trajectories 4 to landing locations at relatively long distances from the rotor 3 are collected on the second conveyor 15 and is conveyed to the second discharge 16. The second group of particles 12 in Fig. 1 is relatively poor in cement rich particles 2a, and is relatively rich in fine aggregate particles 2b and in coarse aggregate particles 2c.

Next, particles of the second group 12 are acted on with at least one further actor 17 to make the particles of the second group 12 follow secondary flight trajectories 18 to effect further separation of the particles of the second group 12. The at least one further actor 17 acts upon the second group of particles 12 to further separate the particles into a first subgroup of particles 23 and second subgroup of particles 25. In Fig. 1 the particles of the second group 12 follow a secondary flight trajectory 18 after being acted upon by the blower 26, the second conveyor 15, the main splitter 27, and the auxiliary splitter 28 as further actors 17. The second conveyor 15 throws particles of the second group 12 off its free end 15c into the secondary flight space 19. The splitter 27 acts on the particles of the second group 12 while they are in flight by splitting them into a first split off subgroup of particles 23 that follow secondary flight trajectories 18 through a first further collection zone 20 to the first subdischarge 22, and a second split off subgroup of particles 25 that follow secondary flight trajectories 18 through the second further collection zone 21 to the second subdischarge 24. The blower 26 blows particles out of the second group 12 while they are in flight in the first further collection zone 20, to form a blown out particle subgroup 26a that is split off by the auxiliary splitter 28 in the first subdischarge 22 to travel to the blown out particle subdischarge 22a. The remaining particles in the first further collection zone 20 are split off by the main splitter 27 and travel to the first split off particle discharge 22b.

Using the controller 34 the separation apparatus 1 can be controlled so as to obtain or maintain a desired composition of the particles 2 in the discharges, in response to fluctuations in one or more of the control parameters: humidity, particle size distribution, composition or water absorption of the particles in the stream 2 and/or the particle (sub)groups.

In particular, particle size and humidity are suitable control parameters, as these can be sensed in-line with robust sensors that are commercially available, e.g. a laser scanner and/or a humidity sensor 35. For example, using the controller 34 the distance between the rotor 3 and the point of abutment q can be adjusted, e.g. to ensure that the first group of particles 11 is rich in particles of relatively small dimensions and relatively low density, and thus relatively rich of cement rich particles 2a having a diameter in the range of e.g. 0-1 mm. Also, the flow of the blower 26 may be increased and the speed of the second conveyor 15 may be decreased, so at to ensure that the second subgroup of particles 25 is rich in particles 2 of relatively large dimensions and relatively high density, and thus relatively rich of recycled coarse aggregates 2c having a diameter in the range of e.g. 4-16 mm.

Fig. 3 shows a schematic side view of a second exemplary embodiment of separation apparatus 1. In this embodiment, the separation apparatus is provided on a trailer 30 so as to be mobile. The trailer includes wheels 31 and a housing 32 that encloses i.a. the primary flight space 8 and the secondary flight space 19. The housing 31 includes a roof 33 with a declining roof section 33a against which the particles 2 acted on by the rotor 3 can have a secondary impact to further release H bonds between cement rich particles and aggregate particles, e.g. H bonds between cement rich particles that travel on the surface of aggregate particles, and H bonds between conglomerated cement particles and aggregate particles.

The infeed 7 is here provided as a conveyor instead of a trough, and the second conveyor 15 1s provided on an upward incline so as to provide a particle funnel together with the declining roof section 33a. The separation apparatus 1 of this second embodiment only includes a single, main splitter 27 in the in the secondary flight space 19. The single splitter 27 acts on the particles of the second group 12 that are thrown of the free end 15c by the second conveyor 15.

In this second embodiment, the second conveyor 15 throws particles of the second group 12 off its free end 15c¢ into the secondary flight space 19.

The splitter 27 acts on the particles of the second group 12 while they are in flight by splitting them into a first split off subgroup of particles 23 that follow secondary flight trajectories 18 through a first further collection zone 20 to the first subdischarge 22, and a second split off subgroup of particles 25 that follow secondary flight trajectories 18 through the second further collection zone 21 to the second subdischarge 24. The blower 26 blows particles out of the second group 12 while they are in flight in the first further collection zone 20 to travel to the particle subdischarge 22, together with particles in the first further collection zone 20 that are split off by the main splitter 27. The remaining particles travel via the second further collection zone 21 to the second particle discharge 22.

Exemplary experimental results with a separation apparatus according to the second exemplary embodiment are depicted in the folowing table:

~ [II [|I]. ” RD ~ HO EEE {Rotor Närke NRUA

In the table, ‘rotor’ refers to the first group of particles that are collected in the first collection zone 9, ‘airknife’ refers to the first subgroup of the second group of particles that is collected in the first further collection zone 20 to travel to the first particle subdischarge 22, and RCA’ refers to the second subgroup of the second group of particles that travel via the second further collection zone 21 to the second particle subdischarge 24.

A coarser size for the ‘rotor’ fraction may e.g. be created by using the controller 34 to adjust the first conveyor 13 relative to the second conveyor to move the point of abutment q away from the rotor 3 so as to create a relatively longer first collection zone 9.

Many variations will be apparent to the skilled person in the art. The separation apparatus may e.g. be a stationary apparatus, a mobile 15 apparatus or a semi-mobile apparatus. Such variations are understood to be comprised within the scope of the invention as defined in the appended claims.

List of reference signs 1 - separation apparatus 2 - particles 2a - cement rich particles 2b - fine aggregates 2c - coarse aggregates 3 - first actor / rotor 4 - primary flight trajectories 5 - drum 6 - hitting plates 7 - infeed 7a - trough 7b - planar chute 8 - primary flight space 9 - first collection zone 10 - second collection zone 11 - first group of particles 12 - second group of particles 13 - first conveyor 13a - first conveying surface 13b - first conveyor distal end 14 - first discharge 15 - second conveyor 15a - second conveying surface 15b - second conveyor proximal end 15¢ - second conveyor free end 16 - second discharge q - point of abutment 17 - further actor

18 - secondary flight trajectory 19 - secondary flight space 20 - first further collection zone 21 - second further collection zone 22 - first subdischarge

22a - blown out particle subdischarge 22b - first split off particle subdischarge 23 - first subgroup of particles 24 - second subdischarge

24a - second split off particle subdischarge 25 - second subgroup of particles 26 - blower 26a - blown out particle subgroup 27 - main splitter

28 - auxiliary splitter 29 - sieve 30 - trailer 31 - wheel 32 - housing

33 - roof 33a - declining roof section 34 - controller - humidity sensor

Claims

Conclusions

1. A separation device for separating particles from a particle stream of crushed concrete, in particular end-of-life concrete, wherein the particle stream comprises cement-rich particles, fine aggregate particles and coarse aggregate particles, the device comprising: - a first actor arranged to act on particles of the stream such that the particles follow primary flight paths, - a primary flight space, adjacent to the actor, for particles acted upon to follow primary flight paths therethrough, to effect separation of the particles, the primary flight space comprising: - a first collection zone, arranged relatively close to the first actor, to receive a first group of particles that have followed a primary flight path to landing locations at relatively short distances from the actor, and - a second collection zone arranged relatively far from the first actor, to receive a second group of particles that have followed a primary flight path to landing locations at relatively far distances from the first actor, - the first collection zone being provided with a first outlet arranged to discharge particles from the first group of particles, - the second collection zone is provided with a second outlet adapted to discharge particles of the second group of particles, and wherein - the first group of particles is relatively rich in cement particles, and relatively poor in fine aggregate particles and coarse aggregate particles, the separation device further comprising:

- at least one further actor adapted to act on particles of the second group such that the particles follow secondary flight trajectories, - a secondary flight space, adjacent to the second outlet, for discharged particles of the second group to follow secondary flight trajectories therethrough, to effect further separation of the particles, the secondary flight space comprising: - a first further collection zone adapted relatively close to the further actor, to receive a first sub-group of particles that have followed secondary flight trajectories to landing locations at relatively short distances from the further actor, and - a second further collection zone adapted relatively far from the further actor, to receive a second sub-group of particles that have followed secondary flight trajectories to landing locations at relatively far distances from the further actor, wherein - the first further collection zone is provided with a first sub-outlet adapted to discharge the first sub-group of particles, wherein - the second further collection zone is provided with a second sub-outlet adapted to discharge particles of the second sub-group of particles, and wherein - the first or the second sub-group of particles is relatively rich in coarse aggregate particles, and relatively poor in cement-rich particles and fine aggregate particles.

The separation device of claim 1, wherein the first actor comprises a rotor, the rotor being adapted to act on the particles by colliding with the particles of the stream so that the particles follow primary flight trajectories.

3. The separation device of claim 1 or 2, wherein the second further collection zone is provided with a second sub-discharge configured to discharge particles of the second sub-group of particles, and wherein the second sub-group of particles is relatively rich in coarse aggregate particles, and relatively poor in cement-rich particles and fine aggregate particles.

The separation device of any one of claims 1 to 3, wherein the further actuator comprises a blower configured to blow particles as a blown-out particle subgroup from the second subgroup through a secondary flight space to a blown-out particle sub-outlet.

The separation device according to any one of claims 1 to 4, wherein the further actor comprises a conveyor belt having a free end adjacent to the secondary flight space, the conveyor belt being adapted to act on particles by conveying the particles of the second group to the free end and throwing the particles off such that the particles follow secondary flight trajectories through the secondary flight space.

6. The separation device of any one of claims 1 to 5, wherein the further actor comprises a splitter arranged in the secondary flight space to act on the particles of the second group by splitting the group into a first split subgroup of particles following secondary flight trajectories towards a first split particle outlet at a first distance from the further actor, and a second split subgroup of particles following secondary flight trajectories towards a second split particle outlet at a second, relatively further distance from the further actor.

7. The separating device according to any one of claims 1 to 6, further comprising a first conveyor belt arranged such that the conveying surface forms at least a portion of the first collection zone,

and/or a second conveyor belt arranged in such a way that the conveying surface forms at least part of the second collection zone.

8. The separation apparatus according to any of claims 1 to 7, further comprising a controller adapted to control at least one of a position and/or speed of a feed, a position and/or rotational speed of a rotor, a conveying speed and/or inclination angle of a first conveyor belt, a conveying speed and/or inclination angle of a second conveyor belt, a distance between a rotor and a point of contact of a first landing surface with a second landing surface, a position, direction, flow rate, and/or speed of a blower, a position, height, and/or angle of a splitter in relation to a composition of the particulate stream.

9. A method for separating particles from a particle stream of crushed concrete, in particular end-of-life concrete, in particular by using a separation device according to any one of claims 1 to 8, wherein the particle stream comprises cement-rich particles, fine aggregate particles and coarse aggregate particles, the method comprising: - acting on particles of the stream with a first actor so that the particles follow primary flight paths so that separation of the particles is achieved, - collecting a first group of particles that have followed primary flight paths to landing locations at relatively short distances from the first actor, - collecting a second group of particles that have followed primary flight paths to landing locations at relatively long distances from the first actor,

- the first group of particles being relatively rich in cement-rich particles, and relatively poor in fine aggregate particles and coarse aggregate particles, - acting on particles of the second group with a further actor so that the particles of the second group follow secondary flight trajectories so that further separation of the particles is achieved, - collecting and discharging a first subgroup of particles that have followed secondary flight trajectories to landing locations relatively short distances from the further actor, and - collecting and discharging a second subgroup of particles that have followed secondary flight trajectories to landing locations relatively long distances from the further actor, - wherein either the first or the second subgroup of particles is relatively rich in coarse aggregate particles, and relatively poor in cement-rich particles and fine aggregate particles.

The method of claim 9, wherein the second subset of particles is relatively rich in coarse aggregate particles, and relatively poor in cement-rich particles and fine aggregate particles.

The method of claim 9 or 10, wherein the first actor interacts with particles by colliding with the particles of the stream such that the particles follow primary flight trajectories.

The method of any one of claims 9 to 11, wherein the further actor blows particles from the second group as a blown-out particle subgroup.

13. The method of any one of claims 9 to 12, wherein the further actor acts on the particles of the second group by splitting the group into a first split subgroup of particles following secondary flight trajectories towards a first split particle outlet at a first distance from the first actor, and a second split subgroup of particles following secondary flight trajectories towards a second split particle outlet at a second, relatively further distance from the further actor.

The separation device or method according to any one of the preceding claims, wherein the first group of particles comprises predominantly cement-rich particles.

The separation device or method of any preceding claim, wherein the second subgroup of the second group of particles comprises predominantly coarse aggregates.

The separation device or method of any preceding claim, wherein the first subgroup of the second group of particles comprises predominantly cement-rich particles and fine aggregates.

17. Coarse concrete aggregates separated from a particle stream of crushed concrete, in particular concrete at the end of its life, in particular by use of a separation device or method of separation according to any one of the preceding claims, the separated coarse concrete aggregates comprising particles of which at least 80% by weight are coarse aggregate particles, and/or of which at least 85% are coarse aggregate particles larger than 4 mm, 95% larger than 2 mm, 99% larger than 1 mm, for example 4-16 mm.