RENOVATION AND PROCESSING OF ASBESTOS-CONTAINING DEMOLITION MATERIAL

Description

[0001] The invention relates to a method and a system for the remediation and processing of demolition material containing mineral and asbestos-containing components.

[0002] In the 20th century, asbestos was a popular building material due to its unique properties (high strength, high heat and acid resistance, and excellent thermal insulation) and was used in a wide variety of applications. Asbestos-containing building materials such as asbestos cement were widespread. Asbestos fibers were mixed with cement to produce items such as asbestos cement sheets, pipes, shingles, and corrugated sheets. Asbestos was also used in plaster, filler, and tile adhesive. In the concrete industry, asbestos-containing spacers (made of fiber cement) were particularly common. Their function was to maintain the correct distance between the reinforcing bars (steel bars) in the concrete and the formwork.

[0003] Due to the significant health risks, the use of asbestos was severely restricted. On November 1, 1993, a ban on the manufacture and use of asbestos was finally enacted in Germany. Asbestos-containing materials (including materials with asbestos residues) must also be disposed of properly and professionally in a landfill. The exact procedures and regulations for asbestos disposal are subject to strict requirements and can vary depending on the country or region. During building renovations or demolitions, asbestos-containing materials are generally sealed on-site in a so-called "black zone" (in so-called "big bags"), the packaging materials are made fiber-free, and the materials are then stored in a landfill. Recycling or processing of asbestos-containing materials is not currently permitted.

[0004] From the document MUELLER A ET AL: "PROCESSING AND UTILIZATION OF CONSTRUCTION WASTE", DISPOSAL PRACTICE, BERTERSMANN FACHZEITSCHRIFTEN GMBH, DE, Vol. 18, No. 10, October 1, 2000 (2000-10-01), pages 13-16 / 17, XP000969412, ISSN: 0724-6870, a method and a system for the processing and utilization of construction waste are known.

[0005] Furthermore, Korean patent KR 100 874 665 B1 relates to a method for recycling construction waste, in particular for producing recycled aggregate material.

[0006] The invention is therefore based on the technical problem of providing a remediation and processing method for asbestos-containing demolition material that enables efficient separation of asbestos-containing and non-asbestos-containing material.

[0007] This problem is solved by the method according to claim 1 and the system according to claim 14. Advantageous embodiments of the present invention are specified in dependent claims 2 to 13 and 15.

[0008] The invention relates to a method for the remediation and processing of demolition material containing mineral and asbestos-containing components, according to claim 1.

[0009] Demolition material includes materials generated during the demolition or renovation of structures such as houses and bridges, as well as construction waste containing mineral building materials and asbestos. Typical mineral building materials used in construction include concrete, gypsum, sand-lime brick, cement, and brick. In the past, asbestos was added to these materials, or they were clad with asbestos, depending on their application. The demolition material is preferably in fragments with a maximum edge length of 80 cm, preferably 40 cm. For this purpose, the demolition material is preferably crushed or pulverized (as a preliminary step). Typically, excavators with gripper-like attachments (pulverizers) are used to crush the demolition material, breaking it down between two jaws. This is advantageous because the crushed demolition material can be easily transported using a wheel loader and / or a conveyor belt.

[0010] In the first process step, the demolition material is crushed (combusted material) to separate the mineral and asbestos-containing components, ensuring sufficient separation of non-asbestos-containing and asbestos-containing mineral components. It is advantageous to break down the non-asbestos-containing and asbestos-containing mineral components into the smallest possible fragments to achieve a high degree of asbestos extraction from the demolition material. The demolition material can be crushed using a crushing machine, preferably a (mobile) impact crusher or jaw crusher.

[0011] Preferably, after the demolition material has been broken up, magnetic components are magnetically separated from it. A magnetic separator can be used for this purpose, for example to efficiently remove metal parts from the broken-up demolition material.

[0012] Following the crushing of the demolition material and the optional step of magnetic separation, the crushed material is dry- or wet-classified. Classification is a mechanical size separation of the bulk feed material (the crushed demolition material / combustion material). Depending on applicable environmental regulations, classification can be carried out without the use of a liquid (dry classification) or with moisture, usually water (wet classification). Dry classification uses a classifying device, such as a screening machine, which, depending on the desired separation criteria, e.g., the number of screen levels with predetermined mesh sizes, separates the feed material according to particle size distribution into at least a fine fraction with small particle sizes and a medium fraction with medium particle sizes. Wet classification involves moistening the crushed material and separating it according to particle size, e.g., using a screening machine.

[0013] If excessively large particles remain in the crushed demolition material, an additional screening stage can be added to separate a coarse fraction with large particle sizes. Dry or wet classification has the particular advantage that the resulting fractions can each be subjected to specific further processing tailored to the individual particle sizes. This means that the fine fraction can be subjected to a different, adapted processing method than the medium (or coarse) fraction.

[0014] Preferably, during the dry or wet classification step, the crushed demolition material is further separated into a coarse fraction. This allows the coarse fraction to be subjected to further crushing, particularly with additional demolition material. Separating a coarse fraction is advantageous when a certain maximum particle size in the crushed demolition material is exceeded. Depending on the crushing equipment used, the particle size distribution after crushing (a breaking process) can be quite broad. If, for example, impact crushers are used, it can be expected that coarse components will remain after the initial crushing and will only reach the desired particle size after further crushing by the impact crusher. The aforementioned crushing step can therefore be supplemented with a recycling loop, i.e.,In a further step, the coarse fraction is broken down to further separate the mineral and asbestos-containing components it contains. Specifically, the resulting coarse fraction is fed back into the impact mill crusher, for example, and thus broken into smaller fragments. Preferably, the coarse fraction is crushed together with other demolition material.

[0015] Preferably, the medium fraction has a grain size of more than 0 mm and up to 32 mm, more preferably from 2 mm to 8 mm. The fine fraction typically consists of (asbestos-containing) concrete sands and / or dusts with a grain size of, for example, less than 2 mm. The coarse fraction consists, for example, of crushed demolition material with a grain size of more than 32 mm, more preferably more than 8 mm.

[0016] According to the invention, the middle fraction is wet-sorted, meaning that the components of the crushed demolition material with medium grain size are separated in a flowing liquid based on their different settling velocities or trajectories – caused by the different densities of the components. By appropriately selecting the liquid, usually water, it can also be achieved that certain components float to the top of the crushed demolition material while others sink due to their higher density. This makes it particularly easy to spatially separate the components of different densities. As a result, fractionation into an asbestos-free mineral fraction, an asbestos-containing (mineral) fraction, and (asbestos-containing) sludge that settles at the bottom can be obtained.Depending on the composition of the demolition material, the asbestos-free mineral fraction represents the light fraction and the asbestos-containing fraction the heavy fraction, or vice versa.

[0017] Asbestos, or rather the asbestos mineral (e.g., crocidolite, approx. 3.2–3.4 g / cm³), has a higher density than mineral building materials such as concrete. Asbestos cement, on the other hand, has a lower overall density than concrete due to its low-density aggregates. Consequently, in asbestos-containing demolition material (e.g., asbestos cement and concrete), the asbestos-containing fraction settles less (light fraction) than the asbestos-free mineral fraction (heavy fraction). With other concrete mixes, the density ratio of asbestos cement to concrete can be reversed, so that the concrete represents the light fraction and the asbestos cement the heavy fraction.

[0018] Furthermore, it is advantageous to perform wet sorting using an upflow or lift-and-lower process. Both processes generate an upward flow in a liquid, albeit in different ways. This flow separates the density of the middle fraction. For the upflow process, a driven propeller located in the liquid, and for the lift-and-lower process, a rising and falling plate, generates the desired flow. This allows lower-density materials (light fraction) to be captured by the flow and transported to the surface of the liquid, while higher-density materials (heavy fraction) sink. By adjusting the propeller's rotational speed in the upflow process, the flow velocity can be adapted to the specific requirements.

[0019] Optionally, the fine fraction and / or the asbestos-containing sludge are bound hydraulically. Hydraulic binding involves immobilizing the asbestos fibers by adding a hydraulic binder (e.g., a cement suspension) that hardens in the liquid / water, thus binding the asbestos. In this bound state, the possibility of asbestos fiber release is largely eliminated.

[0020] Preferably, a further process step is provided in which the fine fraction and / or the asbestos-containing sludge are sorted according to a float / sink method in order to separate the fine fraction and / or the asbestos-containing sludge into an asbestos-free mineral part and an asbestos-containing mineral part. In the aforementioned float / sink method, the fine fraction and / or the asbestos-containing sludge can be placed in a liquid, the density of which is selected such that the asbestos-free mineral part separates from the asbestos-containing part. The density of the liquid is, for example, between the density of the asbestos-free mineral part and the density of the asbestos-containing part. In this process step, the finest asbestos-free mineral components of the broken-up demolition material can thus be separated from the (fine) asbestos-containing part.The liquid contains, by way of example only, iodine (C₂H₅I) or dichloroethane (C₂H₄Cl₂). Preferably, the asbestos-containing part is subsequently bound hydraulically.

[0021] Another aspect of the invention relates to a system for the remediation and processing of demolition material containing mineral and asbestos-containing components. The system according to claim 14 comprises: a crushing machine designed to break up the demolition material in order to separate the mineral and asbestos-containing components; a classifying machine downstream of the crushing machine designed to classify the broken-up demolition material, either dry or wet, in order to separate it into at least a fine fraction and a medium fraction; a sorting machine downstream of the classifying machine designed to sort the medium fraction using a wet stream in order to separate the medium fraction into a heavy fraction, a light fraction and asbestos-containing sludge; where either the heavy fraction is asbestos-free mineral and the light fraction contains asbestos, or the heavy fraction contains asbestos and the light fraction is asbestos-free mineral.

[0022] A (mobile) impact crusher or jaw crusher is preferably used as the crushing device. However, other crushing devices that can reliably reduce (pre-crushed) demolition material to a desired particle size are also suitable.

[0023] The classifying device is preferably a (mobile) screening machine (or a (mobile) screening tower). The screening machine can have several screen decks, each with a screen mesh (or a perforated plate) and a predetermined mesh size (or hole size) to separate the desired fractions.

[0024] The sorting device is preferably designed to separate light materials from heavy materials using an upward flow (e.g., of water). The sorting device can have a separation chamber filled with a liquid (e.g., water) in which an upward flow is generated, e.g., by means of a propeller. Light materials in the separation chamber are thus transported to the surface of the water, while heavy materials sink. This allows for the separation into a light fraction and a heavy fraction. Depending on the composition of the middle fraction (additives, asbestos content), the asbestos-containing component of the middle fraction is separated as either the light or heavy fraction.

[0025] The system may additionally include a buoyancy basin designed to receive a liquid in order to pass the fine fraction and / or the asbestos-containing sludge through the liquid, thus separating the fine fraction and / or the asbestos-containing sludge into an asbestos-free mineral part and an asbestos-containing mineral part.

[0026] Advantages of the system according to the invention and its embodiments, as well as further advantageous embodiments, can be found in the description of the method according to the invention as above.

[0027] The solution according to the invention makes it possible for the first time to separate asbestos-containing and non-asbestos-containing components from demolition material, particularly at the demolition site. This allows valuable building materials to be recovered and asbestos-containing construction waste to be significantly reduced. Furthermore, CO₂ emissions are saved through shorter transport routes and material recovery. The reduction in waste requiring landfill disposal also saves valuable landfill space.

[0028] Preferred embodiments of the present invention are described below with reference to the following figures. These show: Fig. 1 a flowchart illustrating a method according to an embodiment of the present invention and Fig. 2 a schematic representation of an embodiment of the system according to the invention.

[0029] Fig.1 Figure 1 shows a flowchart illustrating a process 10 according to an embodiment of the present invention. The process steps shown are merely examples divided into three so-called "remediation sections" 100-120. Remediation sections are characterized by the fact that in each section the supplied material is classified / sorted into several fractions. They are also subject to different safety regulations. In remediation sections where asbestos-containing material is transported and processed dry, water cannons can be used or the affected work area can be sealed off (so-called "black zone"), whereby a negative pressure relative to the environment is maintained continuously (using appropriate air filters) to prevent the spread of asbestos fibers. Remediation sections in which asbestos-containing components are bound in liquids, on the other hand, require less stringent safety precautions.Flow lines indicated by a dashed arrow represent optional alternatives. Specific occupational safety and environmental protection measures depend on the applicable environmental regulations.

[0030] In the first phase of remediation (phase 100), the demolition material is broken up to separate the mineral and asbestos-containing components. The broken-up material is then dry- or wet-classified to separate it into fine, medium, and, if necessary, coarse fractions. This process utilizes a crusher (e.g., an impact crusher), a magnetic separator, and a classifier (e.g., dry / wet screening technology).

[0031] Pre-crushed or pulverized demolition material containing asbestos and mineral components can be transported and fed into the impact crusher using a wheel loader and, for example, a conveyor belt. 101 The impact crusher crushes 102 the demolition material to a desired particle size (so-called crushed material) in order to separate the mineral and asbestos-containing components. The mineral asbestos-containing crushed material is then optionally fed to a magnetic separator, which collects magnetic components, 103, and then to a dry or wet screening system. The dry or wet screening system is, for example, a screening machine with which the crushed material is dry-classified 104 (or wet-classified with the addition of, for example, water). In the dry or wet screening system, the asbestos-containing mineral material is separated into at least two different particle sizes and discharged. This is crushed demolition material with a fine particle size (fine fraction) 1041, for example.Smaller than 2 mm, and with a medium grain size (medium fraction) 1042, e.g., between 2 mm and 8 mm. The fine fraction may consist of asbestos-containing dust and concrete sand.

[0032] Should coarse components with a large particle size, e.g., larger than 8 mm, remain after passing through the impact crusher, it is advantageous to screen these components as a coarse fraction (1043) and, for example, feed them back into the impact crusher via a conveyor belt. This recirculation process is repeated until the crushed demolition material reaches a particle size below the predetermined large particle size.

[0033] The middle fraction (remediation aggregate fraction) is conveyed, for example, via a conveyor belt to a second remediation section 110, while the fine fraction (concrete sand, dust) is conveyed, for example, via a conveyor belt to a third remediation section 120. The second and third remediation sections are explained below.

[0034] In the second remediation phase 110, the middle fraction 1042 (remediation aggregate) obtained in the first remediation phase 100 is wet-sorted to separate it into three further fractions. These three fractions from the middle fraction are high-density particles, so-called heavy materials (heavy fraction), low-density particles, so-called light materials (light fraction), and sludge 1111. Depending on the composition of the asbestos-containing products used, the asbestos accumulates in the light or heavy fraction 1112, and asbestos-free mineral material accumulates in the heavy or light fraction 1113. A wet separation technique is preferably used for this purpose. A wet separation technique based on an upflow process or using a lifting and lowering technique is conceivable.The choice of separation method ultimately depends on many factors, such as the processing quantity, spatial requirements, the delivery time of the technical equipment, the fiber content in the asbestos-containing demolition material, and economic efficiency.

[0035] The asbestos-containing fraction (light or heavy fraction) is transported, for example, via conveyor belt to a designated area and hydraulically bound. The asbestos-containing fraction must be packaged and disposed of (e.g., in a suitable landfill) in accordance with official regulations. The asbestos-free fraction is transported, for example, via conveyor belt from the wet separation process and consists of asbestos-free mineral material that can be recycled.

[0036] The sludge fraction can alternatively be fed into the third remediation stage 120. Should the third remediation stage 120 not be suitable for further processing of this fraction (e.g., due to quantity or for economic reasons), it can be hydraulically bound 105, preferably packed in big bags, and disposed of in accordance with official regulations (e.g., at a suitable landfill).

[0037] In the third remediation phase 120, the fine fraction and / or sludge are sorted using a float / sink process to separate the fine fraction and / or asbestos-containing sludge into an asbestos-free mineral component and an asbestos-containing component. A buoyancy tank 121 and a water tank 122 can be used for this remediation phase 120. In the buoyancy tank, the fine fraction (dust, concrete sands) and / or the asbestos-containing sludge are passed through a liquid, thus separating asbestos-containing mineral material from asbestos-free mineral material 121. The density of the liquid depends on the type of asbestos used in the demolition material and can range between that of asbestos-containing and asbestos-free mineral particles. The separated asbestos-containing material can then be settled and filtered 123, discharged 1231, and subsequently hydraulically bound 124.For settling and filtering the asbestos-containing material, a settling tank filled with liquid and equipped with a filter cartridge is used, for example. In the settling tank, the heavier fraction sinks to the bottom, while the lighter fraction floats on the surface of the liquid. The settling tank is designed, for example, in the form of an overflow, with the filter cartridge located at the overflow. The floating fraction is retained by the cartridge. The liquid can pass through. Depending on the composition of the asbestos-containing material, asbestos components settle at the bottom of the tank or in the filter cartridge. Finally, the asbestos-containing materials can be hydraulically bound and preferably disposed of in accordance with official regulations (e.g., at a suitable landfill).

[0038] The asbestos-free mineral portion of the classified fine fraction and / or the sorted sludge can then be fed into a water basin for purification 122 and removed 1221. After purification, the asbestos-free mineral portion is then available again for the material cycle.

[0039] The steps of the third renovation phase 120 are purely optional.

[0040] Fig. 2 shows an embodiment of the system 20 according to the invention and is designed such that it performs the method according to Fig. 1 can execute.

[0041] System 20, for example, includes a material feed 201 for receiving (pre-crushed) demolition material containing mineral and asbestos-containing components. From material feed 201, a conveyor belt 202 can lead to the feed 203 of a crushing unit 204, e.g., an impact crusher, to transport the demolition material. The crushing unit 204 is designed to break up the demolition material so that the mineral and asbestos-containing components are separated. For the separation of magnetic substances, a magnetic separator 205 is preferably connected downstream of the crushing unit 204. System 20 also includes a classifier 206, such as a dry / wet screening unit. The classifier 206 dry- or wet-classifies the crushed demolition material to obtain a fine fraction (asbestos-containing dust, concrete sand), a medium fraction (remediation aggregate), and optionally a coarse fraction.The resulting fractions are then available in corresponding outputs, for example, the output for the fine fraction 2061, the medium fraction 2062, and the coarse fraction 2063. A sorting unit 212, e.g., a wet separation unit, is provided for wet sorting the medium fraction. The sorting unit 212 has, for example, a feeder 211 into which the medium fraction (remediation aggregate) can be placed, as well as an output 2123 for the recovered asbestos-free mineral materials (heavy or light fraction), an output 2122 for the asbestos-containing mineral materials (light or heavy fraction), and an output 2121 for asbestos-containing sludge. A station 213 for the hydraulic binding of asbestos-containing material may also be provided. Should the fine fraction obtained from the classifier 206 and / or the sludge obtained from the sorting device 212 require further processing, the system 20 can have a buoyancy basin 222 with a corresponding feed 221.In the buoyancy basin 222, the fine fraction and / or sludge are passed through liquid, thus separating asbestos-containing material from the asbestos-free mineral material, which is then discharged in outlet 2221. A water basin 223 can also be connected downstream of the buoyancy basin 222 to purify the asbestos-free mineral material. The purified material is then available, for example, in outlet 2231 of the water basin 223. The asbestos-containing material recovered in the buoyancy basin 222 can, for example, be sedimented or filtered in a settling basin (with a filter cartridge) 224 and subsequently extracted. The extracted asbestos-containing material can then be hydraulically bound in a station 225.

[0042] Components or systems that are useful for the remediation and processing of asbestos-containing demolition material may be partially omitted, replaced or added. List of reference symbols:

[0043] 10 Methods for the remediation and processing of demolition material containing mineral and asbestos-containing components; 100 First remediation stage; 101 Feeding demolition material into the material feed; 102 Crushing the demolition material (e.g., by an impact crusher); 103 Magnetic separation of magnetic components from the crushed asbestos-containing demolition material; 104 Dry or wet classification of the crushed asbestos-containing demolition material; 1041 Discharge of asbestos-containing dust, concrete sand (fine fraction); 1042 Discharge of asbestos-containing remediation aggregate (medium fraction); 1043 Discharge of an asbestos-containing coarse fraction; 105 Hydraulic binding of the asbestos-containing fine fraction (dust, concrete sand); 110 Second remediation stage; 111 Wet sorting of the medium fraction (e.g.,(using wet current technology or lift-and-lower technology); 1111 Discharge of asbestos-containing sludge; 1112 Discharge of asbestos-containing mineral material (light or heavy fraction); 1113 Discharge of asbestos-free mineral material (heavy or light fraction); 112 Hydraulic binding of asbestos-containing mineral material (light or heavy fraction); 120 Third remediation stage; 121 Separation of asbestos-containing material from the asbestos-free mineral material from the fine fraction and / or sludge; 122 Cleaning of the separated asbestos-free mineral material; 1221 Discharge of the asbestos-free mineral material; 123 Settling and filtering of asbestos-containing material; 1231 Discharge of the asbestos-containing material; 124 Hydraulic binding of the asbestos-containing material; 20 System for the remediation and processing of demolition material; 201 Material feed; 202 Conveyor belt; 203 Task of the crushing device; 204 Crushing device, e.g.Impact mill crusher; 205 Magnetic separator; 206 Dry / wet screening technology / classifier; 2061 Asbestos-containing dust / concrete sand output (fine fraction); 2062 Remediation aggregate output (medium fraction); 2063 Coarse fraction output; 211 Wet density separation; 212 Wet density separator / sorting device; 2121 Sludge output; 2122 Asbestos-containing mineral material output (light or heavy fraction); 2123 Asbestos-free mineral material output (heavy or light fraction); 213 Hydraulic binding station; 221 Buoyancy basin output; 222 Buoyancy basin; 2221 Buoyancy basin output; 223 Water basin; 2231 Asbestos-free mineral material output; 224 Settling basin with filter cartridge; 225 Station for hydraulic binding.

Claims

1. A method for remediating and reconditioning of demolition material containing mineral and asbestos-containing components, the method comprising the following steps: - crushing (102) the demolition material to break up the mineral and asbestos-containing components; - dry or wet classifying (104) the crushed demolition material to separate said crushed demolition material into at least a fine fraction and a medium fraction, characterized in that the method includes the additional step: - wet sorting (111) the medium fraction to separate said medium fraction into a heavy fraction, a light fraction and asbestos-containing sludge, wherein, in the step of wet sorting, the medium fraction is fed into a flowing liquid to separate mineral and asbestos-containing components of the medium fraction according to density and thereby to obtain the heavy fraction, the light fraction and the asbestos-containing sludge, and wherein either the heavy fraction is asbestos-free mineral and the light fraction contains asbestos if the density of the mineral components of the medium fraction is higher than the density of the asbestos-containing components of the medium fraction, or the heavy fraction contains asbestos and the light fraction is asbestos-free mineral if the density of the asbestos-containing components of the medium fraction is higher than the density of the mineral components of the medium fraction.

2. The method according to claim 1, wherein, in the step of dry or wet classifying, the crushed demolition material is additionally separated into a coarse fraction.

3. The method according to claim 2, comprising the further step of: - crushing the coarse fraction to further break up the mineral and asbestos-containing components contained in the coarse fraction.

4. The method according to claim 3, wherein the coarse fraction is crushed together with further demolition material.

5. The method according to any one of claims 1 to 4, comprising the further step of: - sorting (121) the fine fraction and / or the asbestos-containing sludge according to a sink-float process to separate the fine fraction and / or the asbestos-containing sludge into an asbestos-free mineral portion and an asbestos-containing portion.

6. The method according to claim 5, wherein the sorting of the fine fraction and / or the asbestos-containing sludge is carried out by feeding the fine fraction and / or the asbestos-containing sludge in a liquid, the density of the liquid being selected such that the asbestos-free mineral portion separates from the asbestos-containing portion.

7. The method according to claim 6, wherein the liquid comprises iodoethane C2H5I or dichloroethane C2H4Cl2.

8. The method according to any one of claims 5 to 7, comprising the further step of: - hydraulic bonding of the asbestos-containing portion.

9. The method according to any one of claims 1 to 8, comprising the further step of: - hydraulic bonding of the fine fraction and / or the asbestos-containing sludge.

10. The method according to any one of claims 1 to 9, wherein the medium fraction has a grain size of more than 0 mm and up to 32 mm, preferably from 2 mm to 8 mm.

11. The method according to any one of claims 1 to 10, wherein the demolition material is provided in fragments having a maximum edge length of 80 cm, preferably 40 cm.

12. The method according to any one of claims 1 to 11, comprising the following further step performed after the crushing of the demolition material: - magnetic separating (103) of magnetic components from the crushed demolition material.

13. The method according to any one of claims 1 to 12, wherein the wet sorting is carried out by means of an upflow or lift-lower process.

14. A system for remediating and reconditioning of demolition material containing mineral and asbestos-containing components, comprising: - a crushing device (204) configured to crush the demolition material to break up the mineral and asbestos-containing components; - a classifying device (206) provided downstream of the crushing device (204), configured to dry or wet classify the crushed demolition material to separate said crushed demolition material at least into a fine fraction and a medium fraction, characterized in that the system also includes the following: - a sorting device (212) provided downstream of the classifying device (206), configured to sort the medium fraction by means of a wet stream to separate the medium fraction into a heavy fraction, a light fraction and asbestos-containing sludge, wherein the sorting device has a separation chamber comprising means for providing the wet stream into which the medium fraction is feedable to separate mineral and asbestos-containing components of the medium fraction according to density to obtain the heavy fraction, the light fraction and the asbestos-containing sludge, and wherein either the heavy fraction is asbestos-free mineral and the light fraction contains asbestos if the density of the mineral components of the medium fraction is higher than the density of the asbestos-containing components of the medium fraction, or the heavy fraction contains asbestos and the light fraction is asbestos-free mineral if the density of the asbestos-containing components of the medium fraction is higher than the density of the mineral components of the medium fraction.

15. The system according to claim 14, further comprising: - a buoyancy basin (222) configured to receive a liquid to pass the fine fraction and / or the asbestos-containing sludge through the liquid and thereby to separate the fine fraction and / or the asbestos-containing sludge into an asbestos-free mineral portion and an asbestos-containing mineral portion.