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EP4063030A1 - Procédé et installation d'extraction d'une matière sableuse de construction de sol et son utilisation pour la fabrication du béton ou de l'asphalte - Google Patents

Procédé et installation d'extraction d'une matière sableuse de construction de sol et son utilisation pour la fabrication du béton ou de l'asphalte Download PDF

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Publication number
EP4063030A1
EP4063030A1 EP22163317.5A EP22163317A EP4063030A1 EP 4063030 A1 EP4063030 A1 EP 4063030A1 EP 22163317 A EP22163317 A EP 22163317A EP 4063030 A1 EP4063030 A1 EP 4063030A1
Authority
EP
European Patent Office
Prior art keywords
perforation
input material
screening
fraction
screening machine
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22163317.5A
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German (de)
English (en)
Inventor
Jörg K. Müller
Markus Beukenberg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Soil2sand Ug Haftungsbeschraenkt
Original Assignee
Soil2sand Ug Haftungsbeschraenkt
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Soil2sand Ug Haftungsbeschraenkt filed Critical Soil2sand Ug Haftungsbeschraenkt
Publication of EP4063030A1 publication Critical patent/EP4063030A1/fr
Pending legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07B—SEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
    • B07B13/00—Grading or sorting solid materials by dry methods, not otherwise provided for; Sorting articles otherwise than by indirectly controlled devices
    • B07B13/04—Grading or sorting solid materials by dry methods, not otherwise provided for; Sorting articles otherwise than by indirectly controlled devices according to size
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07B—SEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
    • B07B1/00—Sieving, screening, sifting, or sorting solid materials using networks, gratings, grids, or the like
    • B07B1/46—Constructional details of screens in general; Cleaning or heating of screens
    • B07B1/4609—Constructional details of screens in general; Cleaning or heating of screens constructional details of screening surfaces or meshes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07B—SEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
    • B07B13/00—Grading or sorting solid materials by dry methods, not otherwise provided for; Sorting articles otherwise than by indirectly controlled devices
    • B07B13/14—Details or accessories
    • B07B13/18—Control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07B—SEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
    • B07B1/00—Sieving, screening, sifting, or sorting solid materials using networks, gratings, grids, or the like
    • B07B1/46—Constructional details of screens in general; Cleaning or heating of screens
    • B07B1/4609—Constructional details of screens in general; Cleaning or heating of screens constructional details of screening surfaces or meshes
    • B07B1/4645—Screening surfaces built up of modular elements

Definitions

  • the invention relates to a method and a plant for obtaining a new, sand-like soil building material for the production of concrete or asphalt from an input material in the form of excavated soil. Furthermore, the invention relates to the use of the soil building material obtained by the method according to the invention as a sand substitute for the production of concrete or asphalt, i.e. a method for concrete or asphalt production in which the sand-like soil building material is first obtained from the input material in the form of excavated soil and this is then used as a sand substitute used to make the concrete or asphalt.
  • Concrete is one of the most important building materials in the construction industry. It consists of a mixture of cement, concrete aggregate and water and, if necessary, one or more concrete admixtures or concrete additives, and is created by the hardening of the cement-water mixture.
  • Concrete aggregate consists of natural or artificial, dense or porous rock with grain sizes suitable for concrete or asphalt production.
  • Sand is mainly used as an aggregate for normal concrete, eg gravel sand with a maximum particle size of 32mm, which is obtained from river and glacier debris by dredging or suction.
  • Alternative concrete aggregates for normal concrete are crushed stone, grit and crushed sand obtained by crushing or grinding, or granite, porphyry, basalt or limestone.
  • Pumice, expanded clay, lava, crushed bricks and slag are usually used as aggregate for lightweight concrete.
  • a screening plant for separating a particle stream into two particle sizes uses a screen surface inclined in the shape of a stair with holes arranged at the stair nosings.
  • two such sieve surfaces are arranged one above the other, so that three particle streams are obtained.
  • German patent DE 41 21 584 C1 describes coaxial ring screen sections with different hole sizes, which are arranged axially next to each other on the one hand, but also coaxially inside one another on the other hand, so that the input material is divided into several particle streams and certain particle streams are sieved twice.
  • German utility model specification discloses DE 202 18 820 U1 A process for the recovery of material of a specified particle size from waste material which is fed to a screening device and then transported therein over a downstream vibrating screen surface having a first screening area with a first mesh size and a downstream second screening area with a second mesh size, the meshes of which have smaller dimensions than the meshes of the first mesh size.
  • this process does not produce any sand-like soil building material that can be used as a sand substitute for concrete or asphalt production, nor is excavated soil used.
  • the object of the present invention is to provide a simpler and cleaner method and a corresponding plant for carrying out the method, which relates to the extraction of a new soil building material from excavated soil, which has properties of natural sand and is an alternative to sand for the production of concrete or asphalt and is also used for it.
  • the core idea of the invention is to obtain the soil building material by screening the input material or excavated soil, with the soil building material having a particle size distribution of 0 to 2 mm.
  • a screening machine which separates the input material or the fraction into a first grain fraction and a second grain fraction, which forms the soil building material, with a grain size of essentially less than or equal to 2 mm separated by the input material or the fraction being transported in the screening machine over an oscillating screening surface which is directed at least in sections downwards in a working direction and which has at least a first screening area with a first perforation or mesh size, and a second screening area with a second perforation located behind it in the working direction or comprises mesh width, the holes or meshes of which have a smaller dimension in at least one direction than the holes or meshes of the first perforation.
  • the soil building material obtained is then used to produce concrete or asphalt.
  • the second grain size is screened from the material with which the screening machine is fed.
  • the first grain fraction therefore has a lower proportion of grains smaller than 2mm than the input material and is at best cleaned of these grains.
  • the sieving success is all the greater, the smaller the proportion of grains of the second grain fraction remains in the first grain fraction.
  • the first grain fraction thus contains a grain size of essentially larger than 2mm, but also shares of the grain fraction smaller than 2mm.
  • the working direction is the direction in which the material mainly moves in the screening machine during its operation. It also corresponds to the direction of the inclination of the screen surface.
  • the method according to the invention and the corresponding system make soils or excavated soil available for use as building material and building aggregate that have so far remained unused.
  • the soil building material obtained in this way from the soil as an input material has properties comparable to natural sand and can therefore be used as a substitute for sand in concrete or asphalt production.
  • landfill operators, gravel pit operators and civil engineering companies have the opportunity to use their excavated soil as a new source of valuable materials and to make it technically usable for new purposes, in particular for the production of concrete or asphalt. This increases the capacity of landfills and gravel pits can be operated for longer. Due to its sand-like properties, the soil building material obtained from the excavated soil can contribute to covering the growing global demand for sand in the production of concrete or asphalt and thus conserve natural sand resources.
  • the system according to the invention can be set up at the site of an excavation and from the excavated soil there obtained directly the new soil building material as input material for the method according to the invention, which can be further processed on the spot to form concrete or asphalt.
  • the effort, the logistics and the costs for the procurement, the transport of building materials from and to a construction site can be reduced and the intermediate storage of the excavated soil can be avoided.
  • Materials that can be used as input material are basically all mineral, stony, sandy and/or loamy soils, in particular soils with the aggregate according to DIN EN 12620.
  • the input material should be free of components that could damage the concrete - or asphalt production process and the later strength of the concrete or asphalt have a lasting effect.
  • these are in particular organic components such as humus, peat, topsoil, digested sludge and/or plant remains (roots), but also flint and/or flint stones.
  • Non-organic soils are therefore preferred, since the organic components impair the hydration of the hydraulic binder in the concrete or asphalt.
  • the input material can be obtained both from pits, especially excavation pits, and from landfills.
  • the input material should be free of contamination from substances harmful to humans, especially toxins and heavy metals.
  • the percentage yield of the second grain fraction can vary from 0-2mm.
  • the limit value can thus be between 33% and 66%, for example, preferably 50%.
  • the conveying speed of the transport device loading the screening machine can be changed or adjusted at least in one section. In this way, the conveying quantity of the input material per unit of time can be adjusted.
  • the system can include a corresponding system control for setting the conveying speed of the transport device.
  • the assessment or determination of the amount of soil building material, input material or first grain fraction can be based on weight or volume. Furthermore, the evaluation or determination can be carried out by a person operating the system or in an automated manner. If the first and second grain fractions are each thrown onto a cone of heap, for example by means of a conveyor belt, the ratio of the first and second grain fractions can be recognized immediately and qualitatively by comparing the height or size of the cones of heap. The person can recognize when the heap of repose of the second grain fraction, ie the soil building material, is significantly smaller than the heap of repose of the first grain fraction and in this case reduce the conveying speed, ie reduce the amount of input material that is fed to the screening machine.
  • a size comparison of the two material cones can also be done automatically. For example, their diameter and/or height can be recorded with a camera and evaluated, in particular compared, using image processing software. If necessary, a vertical bar around which the respective cone of repose is formed, or a scale on the bottom of the respective cone of repose, e.g. with concentric measuring rings as floor markings, can provide quantitative information about the current height or the current diameter of the cone of repose.
  • a camera in connection with image evaluation software can record these heights and/or diameters and make them available to an evaluation unit.
  • a sensor system for example one or more light barriers, can also be used, which signal to an evaluation unit that a certain height or a certain diameter of the corresponding heap of repose has been reached at a certain point in time, in which case the difference in time between the points in time indicates the size or Indicates the ratio of the two material cones.
  • the evaluation unit can form the size or quantity ratio of the heaped cones and send a control signal to the system controller, as a result of which the latter then reduces the conveying speed of the transport device if the above-mentioned limit value is undershot, in other words, the heaped cone of the second grain fraction is considerably smaller than that Cone of repose of the first grain fraction.
  • This evaluation can be carried out at a specific point in time after the system has been switched on, several times at specific points in time or even continuously as part of a regulation.
  • the mass or weight of the total soil building material obtained can be used and compared with the weight of the input material or the total first grain fraction produced. This can done using scales. For example, the weight of the bunker can be continuously measured. Likewise, the first and/or second grain fraction can be collected in appropriate containers, the weight of which is continuously determined. While the weight of these containers can then be compared directly with one another, the difference in weight for the bunker must first be determined in order to quantify the amount of input material that has already been removed from the bunker. This weight difference can then be related to the weight of the quantity of the second grain fraction.
  • the transport device conveying the input material or its fraction from the bunker to the screening machine preferably has a scale which weighs the material on the transport device at all times. By integrating the measured values over a period of time, the weight of the total input material extracted can be determined.
  • a scale can be part of another transport device that transports the second grain fraction or the soil building material away from the screening machine. By integrating the measured values over the period of time, the weight of the total soil building material extracted or extracted can then also be determined here.
  • the evaluation unit can form the weight ratios and send a control signal to the system control, as a result of which it reduces the conveying speed of the transport device if the above-mentioned limit value is undershot, in other words, the mass of the second grain fraction is considerably smaller than the mass of the first grain fraction or .of the input material.
  • This evaluation can be carried out at a specific point in time after the system has been switched on, several times at specific points in time or even continuously as part of a regulation.
  • the amount of input material to be fed to the screening can also be increased per unit of time if the amount of soil building material obtained in relation to the amount of input material is above the limit value or another limit value that is smaller than the first-mentioned limit value. This makes sense above all in the context of the aforementioned regulation in order to increase the throughput (amount of input material per time) of the plant and thus its profitability.
  • a high yield of soil building material is achieved when the throughput of the plant is set to a value between 50 kg and 200 kg per minute and square meter of screen area, preferably to about 100 kg per minute and square meter of screen area. For example, if the screening area of the screening machine is 20m 2 , the throughput is 2 tons per minute or 120 t per hour.
  • the input material is screened in several stages.
  • an oversized grain is separated in a first screening stage upstream of it.
  • Oversize is that fraction of the input material whose grain size exceeds an upper limit, for example greater than 45 mm. This prevents oversized grain from getting into the screening machine and damaging its screening elements. Because of the vibration of the screen surface, the oversized grain can absorb such great kinetic energy and be accelerated that it breaks through the screen elements when it hits it or the screen holes tear open.
  • the oversize can be separated by a coarse separator, which forms the first screening stage.
  • the screening machine then forms the downstream second screening stage.
  • the input material is then separated by the first screening stage into an oversize fraction and a fraction freed from oversize.
  • the latter is then separated into the first and second grain fractions on the screening machine.
  • the input material has already been freed from oversize, it can be delivered directly to the screening machine.
  • the screen surface is formed by screen elements in the form of rectangular, elongated individual screens that lie against one another on their longitudinal sides, the working direction of the screening machine being transverse to the longitudinal extent of the individual screens, ie in the direction of their width.
  • Elongated individual screens have the advantage that the screen surface can easily be convex or concave.
  • the length of the individual wires can be at least five times, preferably ten times, their width. With a width of approx. 30cm, the individual screens can preferably have one have a length of 3m.
  • the screening machine can have the same or double the width of the individual screens.
  • the individual screens are formed by elastic screen mats, for example made of elastomeric polyurethane. These have the advantage that they absorb the kinetic energy of the larger grains of the input material sent to the screening machine or their fraction freed from oversized grains on impact and thus dampen the grain movement overall. The kinetic energy is transferred to the material on the screen surface by the vibration of the screen surface. Due to the impact, smaller grains of the second grain fraction adhering to the larger grains of the input material are thrown off and can thus fall through the sieve holes. As a result of the damping, the kinetic energy of the grains is prevented from becoming too great and penetrating the individual sieves.
  • the elasticity of the screen mats has the advantage that the screen holes are not rigid in shape and size. Rather, their deformability allows a granule of slightly larger dimension than a screen hole to be pushed through it, particularly when another granule of corresponding size impacts that one granule. Thus, the risk of clogging of the sieve holes by grains that could get stuck in them is minimal. Furthermore, a blockage of the screen openings by fine particles (less than 0.5 mm), which are increasingly deposited on the edge of the screen holes and growing from there and in the worst case close the entire screen hole, is prevented as a result of the possible deformation of the edge of the screen hole by the movement of the coarser grains. In this respect, the elastic screen mats have a self-cleaning effect.
  • a particularly high yield of soil building material is achieved if the individual screens have a screen perforation with elongated screen holes that are oriented parallel to the working direction.
  • the screen holes are preferably in the form of oblong holes, ie they have no inside corners. This has the advantage that they are less clogged with very fine particles and can be cleaned more easily, particularly as part of the aforementioned self-cleaning effect.
  • the vertical up and down movement takes place along an elliptical path.
  • the input material on the screen surface simultaneously receives a movement component in the direction of the working direction and is thus transported forward on the screen surface.
  • the screening machine can have more or fewer individual screens, in particular between 15 and 25 individual screens.
  • the number of individual screens depends on the size of the screening machine. If, purely by way of example, 21 individual screens are used, this results in an area of 18.9 m 2 with a length of 3 m and a width of approx. 30 cm for the individual screens.
  • the use of a comparatively small width of eg 30 cm is advantageous in order to be able to equip the screen surface with as many variants as possible with individual screens with different perforations.
  • the screen surface comprises at least a first screen area with a first perforation or mesh size and a second screen area located behind it in the working direction with a second perforation or mesh size.
  • three or more such screen areas can also be located one behind the other.
  • the individual screens can each have a uniform perforation and each belong to a group, of which at least a first group has a first perforation and a second group has a second perforation, the second perforation being smaller in at least one direction in which the screen holes extend than the first hole is.
  • the individual wires of the first group can then form the first wire area and the individual wires of the second group can form the second wire area.
  • the sieves of a group are always the same.
  • the individual screens belong to one of three groups, each of which has a first, second and third perforation, the second perforation being smaller than the first perforation in at least one direction in which the screen holes extend and the third perforation being smaller in at least one direction in which the screen holes extend than the second hole is.
  • the individual wires of the first group can then form the first wire area, the individual wires of the second group the second wire area and the individual wires of the third group a third wire area which follows behind the second wire area in the working direction.
  • the selection of the perforation or perforation sequence for the individual screen areas is dependent on the moisture content of the input material should in order to get a high yield of soil building material.
  • the sequence of perforations or individual sieves mentioned above is suitable for sieving off the second grain fraction, preferably in the case of comparatively dry input material.
  • a different sequence of perforations can be used with moister input material.
  • larger perforations should be used with increasing moisture in the input material and smaller perforations with dry input material.
  • Soils with a relative humidity (adhesive moisture) or a water content below 8% can be regarded as comparatively dry input material, whereby comparatively moist input material has a higher moisture content than 8% water content.
  • the relative humidity in comparatively dry soils, which form the input material in summer is between 6% and 7%, in particular around 6.6%.
  • the relative humidity of soils, which form the input material in winter is mainly between 10% and 15%, for example 13.8% water content.
  • the input material must not be wet, which is why it should be stored under cover.
  • the moisture content of the input material or a variable dependent on it, such as the electrical conductivity is determined and the perforations or the individual screens are selected and used depending on the moisture content or the variable dependent thereon substantially larger perforation or individual screens with a substantially larger perforation, and at a lower moisture level a substantially smaller perforation or individual screens with a substantially smaller perforation can be used.
  • the terms “smaller perforation” and “larger perforation” refer to the cross-sectional area of the screen holes.
  • wetter input material e.g. ten individual screens with the first perforation, five individual screens with the second perforation and six individual screens with the third perforation can form the screening surface.
  • the number of individual screens can also be different here.
  • the system according to the invention has a first screening machine and a second screening machine to which the input material can be selectively fed, the first screening machine being responsible for drier and the second screening machine for wetter input material.
  • the first screening machine being responsible for drier and the second screening machine for wetter input material.
  • the first and second screening machine can each have a screening surface with at least one first and second perforation, the screening holes of the first and second perforation of the screening surface of the first screening machine having a substantially larger cross-sectional area than the screening holes of the first and second perforation of the screening surface of the second screening machine.
  • the first screening machine can have the first-mentioned perforation sequence (5x25, 3x20, 3x10)
  • the second screening machine can have the last-mentioned perforation sequence (7x25, 5x25, 2x20).
  • the input material can be fed to the respective screening machine via a common transport device, which can be pivoted between the first and second screening machine, for example, and is aligned depending on the input material or its moisture content.
  • the input material can be fed to the respective screening machine through one of the corresponding Transport device assigned to the screening machine takes place, which supplies either only the first or only the second screening machine and is optionally fed from the bunker depending on the input material or depending on its moisture content.
  • lime in particular unhydrated lime (calcium oxide CaO)
  • CaO calcium oxide CaO
  • the moisture content of the input material is determined and lime, in particular fine white lime, is added to it depending on the moisture content. In one embodiment, this can be done in such a way that above a certain moisture limit value, which can be between 8% and 12%, for example, a defined proportion by weight of lime is added, e.g. 1%.
  • adding 1% lime can reduce the relative humidity to 11.24%.
  • 2% (by weight) lime would further reduce moisture.
  • the amount of lime added may vary in a stepwise or linear manner depending on the moisture, for example between 1% lime from 8% moisture and 5% from 20% moisture.
  • lime can be added by emptying a so-called “big bag” filled with lime over a heap of input material and then mixing in the lime using a sieve shovel, a shovel separator or a sieve bucket of an excavator. It is also possible to equip the bunker with an agitator, for example a rotating blade, which mixes the input material with the lime.
  • the addition of lime is a maximum of 5% of the mass of input material. Because with a lime content of more than 5%, the strength of the concrete decreases, which is undesirable. It is therefore preferable to initially work with a small addition of lime, for example 1%. If the yield of soil building material is too low, the screening process can be repeated by adding 1% lime, for example, to the first grain fraction, mixing it up and feeding it to the screening machine.
  • the input material mixed with lime When the input material mixed with lime is mixed, it is aerated at the same time.
  • the input material should then rest, preferably for at least 4 hours. Aeration and resting are of particular importance for the lime (CaO) to bind the moisture (H 2 O) in the input material and form calcium hydroxide (Ca(OH) 2 ) and with the carbon dioxide (CO 2 ) in the air to form calcium carbonate (CaCO 3 ) can react. This inhibits the pozzolanic reaction that would cause the floor material to harden over time, limiting its use.
  • Hardening is disadvantageous, for example, when the base material is used to embed electrical cables, because in this case it is less able to absorb the waste heat of the cable, in other words it thermally insulates the cable, which could lead to local overheating of the cable.
  • lime can be added in the form of a binder, but the proportion of fine white lime should be at least 70%.
  • Dorosol ⁇ can be used as a binder.
  • the moisture content of the second grain fraction or of the soil building material is determined and the amount of input material fed to the screening machine per unit of time is adjusted as a function of the moisture content.
  • the amount of input material to be supplied per unit of time can be reduced for the processing of wetter input material and increased for the processing of drier input material.
  • the electrical conductivity or the electrical resistance of the input material can be measured and the moisture can be determined therefrom.
  • electrodes can be installed in the bunker, which measure the electrical conductivity or the electrical resistance of the input material at the beginning of the process and/or continuously and report this to the system control. Depending on the electrical conductivity or the electrical resistance, this can then increase or reduce the amount of input material that is fed to the screening machine, for example by adjusting the conveying speed of the transport device accordingly.
  • the soil building material obtained or the screened second grain fraction is thrown onto a cone of heap and it is observed whether a ring of coarser grains is increasingly forming around the cone of heap at its foot, i.e. grains with a grain size larger than 2mm.
  • This can be prevented by reducing the amount of input material fed to the screening machine over time, when a ring of coarser grains increasingly forms at the foot of the heap.
  • FIG 1 shows a screening plant 1 according to the invention for obtaining a sand-like soil building material 3, hereinafter called sand substitute 3, for the production of concrete or asphalt from an input material 2 in the form of excavated soil.
  • the system 1 essentially comprises a bunker 4 for receiving input material 2, a first screening stage 8 in the form of a coarse separator 8 and a second screening stage 9 in the form of a screening machine 9, which is located behind the coarse separator 8 in the transport direction of the input material 2.
  • the coarse separator 8 is used to separate oversize 13, in particular with a grain size larger than 45 mm, before the input material 2 is fed to the screening machine 9. At the coarse separator 8, an oversized grain fraction is thus removed from the input material 2, which can damage the screen elements within the Screening machine 9 can lead.
  • the oversize 13 is piled up on a heap, e.g. via a transport device not shown here, and the remainder of the input material 2, hereinafter referred to as fraction 14, which has been cleaned of the oversize 13, is fed to the screening machine.
  • the oversize 13 can be supplied to another utilization.
  • the screening machine 9 serves to separate said fraction 14 into a first grain fraction 12 and a second grain fraction 3.
  • the latter is the sand substitute 3 to be obtained, which has a grain size of essentially 0 to 2 mm and can therefore also be referred to as fine grain.
  • the first grain fraction 12 ideally has a grain size between 2 and 45 mm. In practice, however, it is not possible to screen 100% of the first grain fraction 12 from the fraction 14 of the input material 2, so that the first grain fraction 12 always also contains a more or less large proportion of the second grain fraction 3. The lower this proportion, the higher the yield of the screening plant or the screening success.
  • the first grain fraction 12 and the second grain fraction 3 are each piled up on a cone of heap.
  • the input material 2 is conveyed from the bunker 4 to the coarse separator 8 continuously via a first transport device 5.1, 5.2, which in the variant according to FIG figure 1 consists of a first section 5.1 and a second section 5.2.
  • the transport facilities of Annex 1 can basically be configured in any way. In the variant according to figure 1 they are implemented as a running conveyor belt. Alternatively, they can also be formed by a rotating transport screw. Furthermore, there can also be a combination of conveyor belt and conveyor screw.
  • the conveying speed of the first section 5.1 of the first transport device is adjustable, in particular regulated, in order to set the amount of input material 2 that is processed or transported to the screening machine 9 per unit of time.
  • a motor M is assigned to the first section 5.1, which is controlled by a system controller 15 in order to set its speed, and consequently the conveying speed of the first transport device 5.1, 5.2.
  • the second section 5.2 of the first transport device is operated at a fixed speed. It is possible that the speed of all or only some of the transport devices of the screening plant 1 can be adjusted.
  • a second transport device 6, or second conveyor belt continuously conveys the residual fraction 14 of the input material 2, freed from oversize 13, which the coarse separator 8 outputs, to the screening machine 9.
  • a third transport device 7, or a third conveyor belt conveys the residual fraction 14 screened second grain fraction 3, which outputs the screening machine 9, continuously to a heap.
  • the first section 5.1 of the first transport device and the third transport device 7 are each assigned a scale 10, 11 in order to determine the weight of the bulk material being conveyed in each case. This can be done during ongoing operation, with the weight values being available at any point in time and having to be integrated or added up in order to determine the total amount of material conveyed after a specific time.
  • the measured values of the carriages 10, 11 are fed to the system control 15, which can evaluate them, in particular put them into relation.
  • the screening machine 9 has a screening surface 19 which is directed downwards at least in sections in a working direction 18 and vibrates during operation.
  • the screen surface 19 consists of a first screen area 19a with a first perforation, one in the working direction 18 behind it, the second sieve area 19b with a second perforation and a third sieve area 19c, in turn behind it in the working direction 18, with a third perforation.
  • Each of the perforations is formed by an arrangement of a plurality of screen holes with specific dimensions.
  • the perforation of the second screen area 19b consists of screen holes 17b, which have smaller dimensions in at least one direction than the screen holes 17a of the first perforation.
  • the perforation of the third screen area 19c consists of screen holes 17c, which have smaller dimensions in at least one direction than the screen holes 17b of the second perforation. In other words, the perforation becomes gradually smaller from screen area to screen area.
  • the screen holes 17a, 17b, 17c are in the form of elongated holes whose longitudinal axis is oriented parallel to the working direction 18. The dimensions of these slots relate to the length of their longitudinal axis and their width.
  • the screen holes are only exemplary in terms of their shape, size and arrangement and only shown in the left part of the screen surface 19.
  • Corresponding sieve holes 17a, 17b, 17c are of course also located in the right-hand part of the sieve surface 19, and consequently over the entire sieve surface 19.
  • the sieve holes 17a, 17b, 17c are arranged symmetrically in rows.
  • the screen surface 19 is slightly concave overall. It is oscillatingly mounted and consists of a number of, for example, 21 individual, elongated, narrow screen elements, hereinafter referred to as individual screens 16a, 16b, 16c.
  • the individual screens 16a, 16b, 16c are approx. 3m long and approx. 25-30cm wide. They lie directly next to one another with their long sides, so that their transverse direction, i.e. the direction of their width, corresponds to the working direction 18 .
  • the individual screens 16a, 16b, 16c are elastic screen mats made from elastomeric polyurethane.
  • the perforation of the individual screens 16a, 16b, 16c forms the perforation of the corresponding screen area 19a, 19b, 19c.
  • the individual screens 16a, 16b, 16c thus belong to one of three groups, each having a first, second and third perforation, the second perforation being smaller in at least one direction of extent of the screen perforations 17b than the first perforation and the third perforation being smaller in at least one direction of extent of the screen holes 17c is smaller than the second hole.
  • the individual screens 16a of the first group form the first screening area 19a
  • the individual screens 16b of the second group form the second screening area 19b
  • the individual screens 19c of the third group form the third screening area 19c, which follows in the working direction 18 behind the second screening area 19b, which in turn behind the first Sieve area 19a is located.
  • the first sieve area 19a consists of a number of individual sieves 16a with the first perforation
  • the second sieve area 19b consists of a number of individual sieves 16b with the second perforation
  • the third sieve area 19c consists of a number of individual sieves 16c with the third perforation.
  • the perforations are therefore always larger than the nominal sand grain size of 0-2mm. Because deposits form at the edge of the hole, so that the effective perforation is smaller. Due to the fact that there is also material with a larger grain size, ie 2-45 mm, on the screen surface 19, these deposits are removed again, so that the screen holes 16a, 16b, 16b do not become overgrown but remain free.
  • the two sieve sequences mentioned are in accordance with the table figure 3 specified. Investigations have shown that the first-mentioned sieve sequence is suitable for wetter input material 2 and the other sieve sequence for comparatively dry input material in order to obtain a comparatively high yield of sand substitute 3 from the input material 2.
  • the conductivity of the input material 2 can be easily measured and allows a statement to be made about the moisture content and the salt concentration of the material, since water dissolves the ions in the soil and enables their transport under the influence of an electric field.
  • the 0-2mm grains of the second grain fraction 3 forming the sand substitute in fraction 14 of the input material 2 fall through the sieve holes 17a, 17b, 17c and are taken away from the sieve machine 9 by a third transport device 7 in the form of a conveyor belt and deposited threw up a heap.
  • the larger grains with grain sizes between 2 and 45 mm that do not fit through the sieve holes 17a, 17b, 17c as well as unscreened 0 to 2mm grains are transported in the working direction 18 and fall off the sieve surface 19 at the end of it. They form the first grain fraction 12 and are also taken away from the screening machine 9 by a fourth transport device 7a in the form of a conveyor belt and thrown onto a heaping cone.
  • the first grain fraction 12 can also be used separately. It makes sense to store the first grain fraction 12 and the second grain fraction 3 in a covered place to protect them from rain and moisture.
  • the screening process can be repeated by first grain fraction 12 is returned to the bunker 4 and fed back to the screening machine 9.
  • the throughput of the screening machine 9, or the amount of input material 2 fed to the screening machine 9 per unit of time, can also be reduced by reducing the speed V belt of the first section of the first transport device 5.1.
  • the said ratio (Grain ratio) are fed to the system control 15, which then makes the appropriate speed adjustment.
  • a flip-flow screening machine for example, can be used as the screening machine 9, as is described in the international application WO 2007/060155 A1 is described.
  • This screening machine 9 consists of a single screen deck and may have a 10°-18° downwardly inclined screening surface 19 curved in a banana (concave) shape.
  • the vibration of the screen surface 19 is preferably vertical along an elliptical path with a frequency of, for example, 800 min -1. This frequency can be excited by a single unbalance shaft drive.
  • the screen surface 19 forms a cantilever with a circular amplitude and a superimposed elliptical amplitude excited by resonance.
  • Input material 2 is excavated soil from pits or landfills with non-organic, mineral, stony, sandy or loamy and uncontaminated soil. Before loading the bunker 4, it can be piled up to form a heaping cone, from which the bunker 4 is then loaded.
  • the input material 2 can be subjected to pre-processing. Such pre-processing is also advisable if the yield of sand substitute 3, i.e. the percentage of the second grain fraction 3 (0-2mm) in relation to the amount of input material 2 or in relation to the first grain fraction 12, is too low.
  • Lime can be added in the form of so-called BigBags, which are emptied onto the dumping cone and mixed in using a shovel wheel loader.
  • a controllable device for metering the addition of the lime and with a mixer, e.g. a rotating blade.
  • a test of its pH value can be carried out after the lime has been added. If the pH is less than 11, there is a guarantee that there is no longer any unbound or reactive calcium hydroxide in input material 2. As a result, a pozzolanic reaction is no longer possible and the input material 2 remains capable of digging and spreading.
  • the input material can be processed in the simplest case with a so-called shovel separator, which is available as special equipment for hydraulic excavators or shovel wheel loaders, or with similar special equipment, which achieves a high level of digestion of the input material 2 during mixing becomes.
  • This effect can also be achieved by stationary, mobile or semi-mobile devices that are designed accordingly, such as so-called disk separators based on the disk-in-disk principle or comparable mechanical devices.
  • the interlocking of the discs and chisels closes the input material 2 as best as possible, which is then mixed with the lime and this can be evened out in the input material.
  • the spaces between the panes can never become clogged, even with very moist, cohesive or soggy soil, because they are constantly being cut free by the panes on the opposite side. It is also possible to let air flow through the bunker 4 from below. If the mixing plant is also in operation, the input material 2 is also well aerated.
  • the pozzolanic reaction With the carbonation (conversion of the hydrated lime into calcium carbonate), the pozzolanic reaction is stopped to a certain extent. This is always the case when the proportion of unbound lime is so low that no more hydrate phases can be formed and the pozzolanic reaction cannot continue.
  • the shovel separator also has a sieving function, so that the specified grain sizes for further use can be produced in connection with the mixing process. These granulations are made possible depending on the individual disc distances of the separator shafts.
  • the yield of sand substitute 3 i.e. the percentage of the second grain fraction 3 (0-2mm) in relation to the amount of input material 2 or in relation to the first grain fraction 12 is too low, after the pre-processing of the input material 2 is too low or continues to increase is low, the addition of lime followed by aeration and allowing the input material 2 to rest can be repeated.
  • Another parameter for controlling the system 1 is the moisture content of the input material 2 .
  • This can be determined, for example, in the bunker 4 using the electrical conductivity of the input material 2 and fed to the system control 15 .
  • the actual input quantity per time or belt speed V belt is therefore a function of its moisture content (in %) and the proportion of fine grain in the medium grain. Schematically shows figure 5 this connection.
  • Curve A describes the case where too little fine grain remains in the middle grain and curve C that too much fine grain remains in the middle grain.
  • Curve B describes the optimal case between these borderline cases.
  • the sand substitute 3 obtained according to the invention can be stored and then used for the production of concrete or asphalt.
  • test cubes can be produced from concrete or asphalt and examined in the laboratory.
  • the salt content of all aggregates in the concrete does not exceed 0.4%.
  • the salt content in the sand content of the concrete (typically 25-30%) must not be more than 0.15%.
  • the salt content can be determined via a conductivity measurement.
  • the pH must also be less than 11. This can easily be measured.
  • the pH value can be adjusted by adding DOROSOL ® .
  • the proportion of dust in the fine grain must be less than 3%.
  • the invention also includes any changes, alterations or modifications of exemplary embodiments which have the exchange, addition, alteration or omission of elements, components, method steps, values or information as their subject matter, as long as the basic idea according to the invention is retained, regardless of whether the change, alteration, or modifications improves or degrades an embodiment.

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  • Combined Means For Separation Of Solids (AREA)
EP22163317.5A 2021-03-26 2022-03-21 Procédé et installation d'extraction d'une matière sableuse de construction de sol et son utilisation pour la fabrication du béton ou de l'asphalte Pending EP4063030A1 (fr)

Applications Claiming Priority (1)

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DE102021107719.2A DE102021107719B3 (de) 2021-03-26 2021-03-26 Verfahren zur Gewinnung eines sandartigen Bodenbaustoffs und dessen Verwendung zur Herstellung von Beton

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Publication number Priority date Publication date Assignee Title
CN116851256A (zh) * 2023-07-11 2023-10-10 丽水学院 一种利用赤铁矿尾砂制备龙泉青瓷茶具的加工设备

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DE4121584A1 (de) 1991-06-29 1993-01-21 Messerschmitt Boelkow Blohm Verfahren und einrichtung zur radartarnung bei triebwerken
WO1997048503A1 (fr) 1996-06-20 1997-12-24 Tinsley, Inc. Vibro-separateur de particules
JP2873158B2 (ja) * 1993-12-28 1999-03-24 株式会社中井産機 振動篩機
DE20205891U1 (de) 2002-04-16 2002-11-14 Arweiler, Armin, 66740 Saarlouis Wellen für Schaufelseparator
DE20218820U1 (de) 2002-11-13 2003-03-20 J. WILLIBALD GmbH, 88639 Wald Absiebvorrichtung
US20040091319A1 (en) * 2001-03-09 2004-05-13 Jurgen Schenk Treatment method and device, in particular for excavation material
KR100459316B1 (ko) * 2002-11-25 2004-12-03 주식회사 스페코 골재 선별기
WO2007060155A1 (fr) 2005-11-24 2007-05-31 Binder + Co Ag Mat flexible de tamisage fin
WO2017019580A1 (fr) * 2015-07-24 2017-02-02 Schlumberger Technology Corporation Ensemble tamis à feuille perforée
US20180236494A1 (en) * 2017-02-23 2018-08-23 Frito-Lay North America, Inc. Separation apparatus with screen having fixed, non-uniform openings
DE102019214864B3 (de) * 2019-09-27 2020-06-18 Thyssenkrupp Ag Verfahren und Vorrichtung zum Ansteuern und Regeln einer Siebvorrichtung sowie Verwendung
US20210016297A1 (en) * 2019-07-16 2021-01-21 Derrick Corporation Smart solids control system

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DE4121585C1 (fr) 1991-06-29 1992-08-06 Lintec Gmbh & Co Kg, 2114 Hollenstedt, De
DE102018006507B4 (de) 2018-08-17 2020-04-30 Lars Fabricius Trommelsiebmaschine

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Publication number Priority date Publication date Assignee Title
DE4121584A1 (de) 1991-06-29 1993-01-21 Messerschmitt Boelkow Blohm Verfahren und einrichtung zur radartarnung bei triebwerken
JP2873158B2 (ja) * 1993-12-28 1999-03-24 株式会社中井産機 振動篩機
WO1997048503A1 (fr) 1996-06-20 1997-12-24 Tinsley, Inc. Vibro-separateur de particules
US20040091319A1 (en) * 2001-03-09 2004-05-13 Jurgen Schenk Treatment method and device, in particular for excavation material
DE20205891U1 (de) 2002-04-16 2002-11-14 Arweiler, Armin, 66740 Saarlouis Wellen für Schaufelseparator
DE20218820U1 (de) 2002-11-13 2003-03-20 J. WILLIBALD GmbH, 88639 Wald Absiebvorrichtung
KR100459316B1 (ko) * 2002-11-25 2004-12-03 주식회사 스페코 골재 선별기
WO2007060155A1 (fr) 2005-11-24 2007-05-31 Binder + Co Ag Mat flexible de tamisage fin
WO2017019580A1 (fr) * 2015-07-24 2017-02-02 Schlumberger Technology Corporation Ensemble tamis à feuille perforée
US20180236494A1 (en) * 2017-02-23 2018-08-23 Frito-Lay North America, Inc. Separation apparatus with screen having fixed, non-uniform openings
US20210016297A1 (en) * 2019-07-16 2021-01-21 Derrick Corporation Smart solids control system
DE102019214864B3 (de) * 2019-09-27 2020-06-18 Thyssenkrupp Ag Verfahren und Vorrichtung zum Ansteuern und Regeln einer Siebvorrichtung sowie Verwendung

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