CH717642A1 - Processing of bituminous secondary raw materials. - Google Patents

Abstract

In a method for separating bituminous material from a matrix of a bituminous secondary raw material, the following steps are carried out: mixing the bituminous secondary raw material with a liquid to form a mixture; separating at least part of the bituminous material from the matrix.

Description

technical field

The invention relates to a method for separating bituminous material from a matrix of a bituminous secondary raw material. The invention also relates to a device for carrying out a method.

State of the art

[0002] Roads have been covered with a bituminous pavement for more than a century. The bituminous road surface typically consists of a top layer, which forms the road surface, a binder layer, a base layer and a foundation layer. The lower layers, in particular the foundation layer, do not necessarily have to comprise bituminous material. The bituminous road surface includes, among other things, bituminous material, grit, sand, filler and binder.

[0003] Bitumen is a by-product of petroleum distillation. It can be assumed that with a reduction in the demand for fuel due to the boom in alternative drives (electricity, hydrogen, etc.), bitumen production will also decline. Thus, in addition to the economic and ecological aspects, methods for recovering the bituminous material will become more relevant in the future.

Bitumen, roofing felt and similar building materials based on bitumen are produced from residues of crude oil after atmospheric distillation and/or cracking.

[0005] The road bitumen is standardized and classified according to its properties (e.g. needle penetration or the like). Due to these properties, an ideal building material can be selected in different climatic conditions. In order to produce the road surface, the road bitumen is heated to 120 to 230 °C and mixed with a proportion of 5 to 7 wt. % added to the granules, sand, especially crushed sand, splitter and filler. Granules, sand and filler are preheated to 150 to 400 °C to expel residual water. The mass is then rolled and thus forms a very resistant covering which contains practically no water. These coatings are therefore insoluble in water and very resistant. The production parameters and the composition of the asphalt pavement can vary.

Over time, the top layer wears out, the granules on the surface are rounded or even flattened by wear, which makes the top layer slippery. In addition, ruts form over time. In this case, the road has to be repaired by removing a few centimeters of the top layer by milling and then applying a new top layer. If the streets have to be completely renovated, the entire surface is broken out and then the street is rebuilt.

The direct recycling by adding a portion of the removed bituminous road surface material to the new superstructure is not possible in every application, especially when higher demands are placed on the quality of the asphalt surface. Thus, the removed bituminous road surface materials are often disposed of in a complex manner.

Presentation of the invention

The object of the invention is to create a method belonging to the technical field mentioned at the outset, with which bituminous material can be separated from a matrix of a bituminous secondary raw material.

The solution to the problem is defined by the features of claim 1. According to the invention, the bituminous secondary raw material is mixed with a liquid to form a mixture, whereupon at least part of the bituminous material is separated from the matrix. This allows the bituminous material and minerals to be easily recovered and reused. The bituminous material can, for example, in turn be used to manufacture products from which the secondary raw material was obtained. The advantage of using it in the same application from which the secondary raw material comes is that residues in the bituminous material do not have to be isolated or not completely isolated from the bituminous material.

The term “secondary raw material” is understood to mean material that has already been used technically once and is now to be used technically a second time by processing.

The liquid serves to ensure that after the bituminous material has been detached, the same can be transported away efficiently. The use of the liquid can optionally also have the advantage that it can penetrate between the matrix and the bituminous material and support the separation process. Depending on its polarity, the liquid can also be used to dissolve foreign substances in the matrix and/or the bituminous material.

In a preferred embodiment, however, the liquid comprises at least a main portion which is polar or consists of a polar liquid. This has the advantage that the non-polar bituminous material does not dissolve in the polar liquid, so that the bituminous material can be separated from the liquid in a particularly simple and particularly economical manner. This means that, for example, there is no need for time-consuming distillation or extraction. The separation can in principle be carried out by known methods, e.g. B. filter, skim off, grind etc.

Preferably the bituminous material is collected at a liquid surface of the mixture. This has the advantage that the bituminous material can be removed from the mixture particularly easily, in particular by skimming, decanting, etc. There are different techniques which can favor the accumulation of the bituminous material on the liquid surface, in particular, for example, by the choice of liquid with high density (see below). However, it is not absolutely necessary that the liquid has a higher density than the bituminous material (see below).

In variants, the bituminous material can also be intercepted in the liquid, for example by filters, adsorption materials or the like. Furthermore, the bituminous material can be discharged at a container bottom, in particular if, for example, the bituminous material has a higher density than the liquid. The bituminous material can also be separated from the sediments and rocks using a centrifuge or grinding.

The bituminous secondary raw material preferably comprises bituminous road surface material, a bituminous road surface concentrate produced from bituminous road surface material, in particular by a mechanical concentration process, particularly preferably by an abrasion process, and/or bituminous roofing felt.

[0016] In the present case, the secondary raw material includes, in particular, the bitumen-containing road surface materials that occur during road rehabilitation. This includes the bituminous layers of the road pavement, typically the wearing course, the binder course, the base course and possibly the foundation course of asphalt roads. During road rehabilitation, the road surface is either completely demolished (surface course together with one or more base courses) or the surface course (at least the asphalt surface course, possibly also the binder course) is milled off. In the following, road surface material is understood to mean both the demolition material and the milled material.

[0017] In addition, chippings, sand and filler are recovered from the bituminous road surface material using the so-called abrasion process (dry or wet). With the attrition process, the bituminous material is abraded from grit, sand and filler, whereby on the one hand the grit, sand and filler and on the other hand the abrasion (a bituminous pavement concentrate in which the bituminous material is concentrated by a mechanical process) is recovered - this Method is known to the person skilled in the art. The chippings, sand and filler can be reused for the production of road surfaces, if necessary after a sieve separation. Hitherto, the debris obtained by the attrition process has been disposed of. The abrasion comprises a larger proportion of bituminous material than the demolition material or the milled material and is therefore particularly suitable for the present method, especially since a smaller container volume can be used with the same yield of bituminous material, which in turn means that less liquid has to be used and a Energy expenditure can be reduced accordingly (possible heating, stirring, etc.). Abrasion is also subsumed under the term road surface material. However, the present method is particularly suitable for separating bituminous material from demolition material and milled material from pavement materials. These two materials pose a particular challenge for the separation into bituminous material and matrix, since on the one hand the fragments or the grain size are relatively large and on the other hand the content of bituminous material is correspondingly lower than in the case of abrasion. In this sense, abrasion places lesser demands on the process.

As part of the abrasion process, chippings and sand may not be sufficient or not completely freed from the bituminous material, in particular, for example, concave areas of the grains cannot be freed from the bituminous material. The grit and sand that is present after the abrasion process is also subsumed under the term secondary raw material and can therefore also be subjected to the present process. This means that grit and sand with greater purity can be achieved. In variants, the chippings and sand can also be reused directly after the abrasion process.

It is clear to the person skilled in the art that other bituminous road surface concentrates can also be used as secondary raw materials in the process. The concentration of the bituminous material can also be achieved via the present method itself, which can equate to going through the method several times. However, the parameters (additives, temperature, etc.) can differ.

Concretely, the road surface materials can include asphalt base courses, asphalt binder courses, asphalt concrete, stone mastic asphalt, mastic asphalt, porous asphalts, SAMI layers and asphalt-containing surface treatments of road surfaces, etc.

The secondary raw material can also include roofing felt. Roofing felt or tar paper is bitumen-soaked cardboard, which is used, for example, as a moisture barrier under the roof tiles. The roofing felt can include coarse-grained sand, fine gravel or slivers of slate, which achieve higher abrasion resistance and UV resistance. Furthermore, the secondary raw material can also include other bitumen-containing building materials, in addition to the road surface materials and the roofing felt, namely, for example, sealing sheeting, insulation, adhesive compounds, impregnating compounds, sealing compounds, etc.

The method can also be used to decontaminate soils contaminated with apolar substances. The soils may be, for example, soil horizons below the H, L, and O soil horizons (organic soil horizons), preferably, for example, A horizons, B horizons, C horizons, and others. The method can be used, for example, to remediate the soil of a contaminated industrial site. The method can also be used to decontaminate soil after an environmental disaster. The method can be used, for example, after an oil tanker accident to decontaminate beach floors. The method can also be used to clean soil contaminated with motor oil in the event of traffic accidents. The method can also be used to remove engine oil from minerals in road drains.

With this method, for example PAH (polycyclic aromatic hydrocarbons), fibers, particles and other additives such as mineral additives (e.g. basalt), metallic additives or plastic additives (aramid, etc.), which may be present in asphalt mixtures from old roads , can be removed particularly effectively and safely. This process can also be used to separate metals as part of the cleaning of waste, such as incineration residues such as slag and smoke ash.

[0024] This method can also be used to remove bituminous or oily residues from sand, for example as part of cleaning the sand on a beach to deal with ecological catastrophes, for example caused by vehicle accidents (car, truck, plane, ship accidents, etc.) be removed.

[0025] The person skilled in the art is also aware of other bituminous secondary raw materials in which the bituminous material can be at least partially separated by means of the method.

A density difference between the bituminous material floating on the surface and the remaining mixture is preferably increased by adding at least one first substance that influences the density. By increasing the difference in density, the buoyancy of the bituminous material can be increased after separation from the matrix, which means that the bituminous material reaches the liquid surface more quickly. This in turn makes the separation process more efficient and faster to carry out.

In variants, it is also possible to dispense with adding the first substance.

Preferably the liquid is water. A polar, inexpensive, non-toxic liquid that is easy to process is thus selected for the process, with which the process can be carried out particularly economically. Furthermore, water has a particularly high surface tension, with which a separating layer of the floating bituminous material can be kept particularly stable.

Other liquids can also be used in variants, in particular for example phenol, cresol, liquid sulfur dioxide, nitrobenzene, aniline, toluidine, nitrotoluene, crotonaldehyde, acrolein, dichloroethyl ether, furfural, ethylaniline, dichlorobenzene or mixtures of the aforementioned liquids with or without additives of benzene. Other organic solvents such as alcohols, polyols such as glycerol, oils, acids, bases or mixtures of the aforementioned liquids are known to the person skilled in the art and can be used for this purpose. However, the organic solvents have the disadvantage that an economical and ecological separation process can hardly be achieved with them. However, the process can be carried out particularly efficiently for small amounts.

[0030] Furthermore, there is also the possibility of using a supercritical gas, in particular supercritical CO2 due to its apolar property, for the separation of bituminous material from the matrix.

Preferably, the first substance influencing the density comprises a water-soluble first substance, in particular an alkali or an acid such as sodium hydroxide (NaOH) or a salt, preferably sodium chloride, magnesium chloride, calcium chloride, potassium chloride, sodium carbonate, sodium nitrate, sugars such as polysaccharides, Glucose, fructose, sucrose, suspended matter (eg filler) etc. or a mixture thereof, or a water-soluble liquid, in particular a water-soluble polyol such as glycerine, which is added directly or indirectly to the mixture.

The use of salts or sugar has the advantage that they typically have good solubility in water. The salts, in particular alkali metal and alkaline earth metal halides, are particularly inexpensive and at the same time easily soluble in water and environmentally friendly. Carbonates and nitrates also have good solubility in water. The carbonates, in particular sodium carbonate, have the advantage that they are chloride-free and nitrate-free and are therefore particularly environmentally friendly. The person skilled in the art is aware of other salts which are also sufficiently water-soluble and can therefore be used to increase the density. Other possibilities are the polyols, which are typically miscible with water in any ratio and can therefore also be used. Of the polyols, glycerin is particularly preferable because it is particularly inexpensive and at the same time non-toxic.

In a preferred method, the liquid is processed after the separation process and used again for a separation process. When processing the liquid, it is not necessary to separate the first substance, since the increased density can also be used in a subsequent process for separating bituminous material from a matrix. The liquid can also be reused directly for the separation process without treatment. A lower addition of additives to increase the density can be provided or dispensed with, especially since, for example, suspended matter such as filler, sludge or other additives, which were added to the liquid in previous separation processes and are therefore still present in the liquid, with which the Density is possibly already sufficiently increased.

In variants, the additives to increase the density can also be dispensed with. Experiments have shown that, particularly in a process in which the secondary raw material has previously been subjected to an abrasion process, the first substance can be dispensed with, in particular from an economic and ecological point of view - it is clear to the person skilled in the art that the first substance can nevertheless benefit the process. Other substances can also be added to increase the density. Many other possibilities are known to the person skilled in the art.

Furthermore, the additives to increase the density can optionally be dispensed with if the temperature of the mixture is heated to more than 35° C., since the density of bitumen is lower than that of water from a limit temperature of 35° C. (It should be noted that depending on the type of bitumen, the limit temperature can also be lower or higher). At a temperature below 35 °C either the additives to increase the density can be added or the bitumen can be separated by other techniques (see below). But even at temperatures above 35 °C, the addition of additives to increase the density can be helpful in order to increase the density difference between the bitumen and the liquid, which means that the buoyancy of the bitumen and thus the separation process is accelerated.

Increasing the water density can also be dispensed with. In this case, the bitumen can be precipitated. A lower temperature (below 35 °C) is particularly advantageous for precipitating the bitumen, since in this temperature range the density of bitumen is greater than the density of water. The separation of bitumen and mineral materials can be removed, for example, by means of a selective auger that only picks up stones and sand. Furthermore, the bitumen can be scraped continuously or intermittently from the bottom of the reactor.

If the bitumen is kept in suspension due to a small difference in density to the liquid or despite higher density due to an agitator, the suspension can be passed through a separator in a continuous process in order to separate the bitumen, with the liquid being fed back into the process can. The separator may, for example, comprise an aspirator or a decanter.

Another possibility is to cyclone the liquid during processing and remove the bitumen in suspension by a pumping and water separation process (e.g. cyclone, filter). The separated liquid can optionally be added back to the reactor.

Preferably, the density-influencing first substance comprises a non-polar first substance which has a lower density than the bituminous material, the non-polar first substance being added to the bituminous material. In this way, the density of the floating bituminous material can be reduced, which can counteract sinking into the liquid. A large number of such non-polar substances are known to the person skilled in the art. For example, in particular gases such as air, CO2, low-molecular, aliphatic hydrocarbons such as propane, butane can be used. In principle, any petroleum fractions can be added which have a lower density than that of the bitumen. In the method, a film or a liquid layer can be formed with the non-polar first substance on the liquid surface, with which rising bituminous material dissolves in the non-polar first substance and thus cannot sink again.

In variants, the non-polar first substance can also be dispensed with.

A chemical and/or physical reaction in the mixture is preferably produced by adding at least one second substance. With a suitable reaction, the adhesive force between the bituminous material and the matrix can be reduced, with which the separation process can be optimized. Secondary effects of the reaction (generation of heat, formation of bubbles, etc.) can also lead to better separation of the bituminous material from the matrix. However, the matrix itself could also be attacked or dissolved by the chemical and/or physical reaction.

In variants, the addition of the second substance can also be dispensed with. Tests have shown that, particularly in a process in which the secondary raw material has previously been subjected to an abrasion process, the second substance can be dispensed with, particularly from an economic and ecological point of view. It is clear to the person skilled in the art that the method can be promoted with the use of a second substance.

Preferably the second substance comprises sodium bicarbonate and/or acetic acid. Both sodium bicarbonate and acetic acid are particularly preferably added. Bubbles can thus be generated in the mixture, which carry dissolving bituminous material upwards to the surface of the liquid (see below). Furthermore, the individual second substances can serve to detach the bituminous material from the matrix.

In variants, the addition of sodium bicarbonate or acetic acid can also be dispensed with.

The second substance preferably comprises a release agent, in particular a peroxide, preferably hydrogen peroxide, oxygen, hydroxide radicals, perhydroxyl, peroxide, bicarbonates, percarbonates, benzene hydroxide, alkali metal peroxides (sodium, potassium, lithium) or a combination of the above. With the use of separating agents, in particular for example hydrogen peroxide, organic molecules, in particular organic polymers and oils, can be broken up by means of free radicals, with which the bond between the bituminous material and the matrix can be loosened. Furthermore, the use of hydrogen peroxide, for example, can attack limestone on the surface, which means that the bituminous material can be detached more easily as a result of this dissolution reaction of the limestone surface. It is not necessary to completely dissolve the limestone. An analogous effect with other matrix materials can also be achieved with peroxides or other substances. Corresponding reactions are known to those skilled in the art. The peroxides can be particularly effective in combination with surfactants.

In variants, the substances mentioned above can also be dispensed with.

The second substance preferably comprises surfactants and/or ambiphiles. Especially in combination with peroxides, preferably hydrogen peroxide, a particularly efficient detachment of the bituminous material can be achieved. Hydrogen peroxide acts as a catalyst, creating a foam layer in which the bituminous material is emulsified. Due to the oxidative effect of the peroxide, organic pollutants are also broken down and transferred to the emulsion.

In variants, the surfactants or the ambiphiles can also be dispensed with.

The second substance is preferably generated using an electrochemical and/or chemical system. The second substance can thus be produced and dosed in situ. This is particularly advantageous for substances with a higher hazard potential, such as a strong oxidizing agent, since safe working is possible.

In variants, it is also possible to dispense with the on-site production of the second substance.

The second substance is preferably added to the mixture in a time-distributed manner so that an overreaction can be prevented. In particular, this prevents sand and filler being carried to the surface of the liquid together with the bituminous material due to excessive formation of bubbles.

The second substance is preferably added continuously or in several portions during the separation of at least part of the bituminous material from the matrix. This can prevent an overreaction, which means that the bituminous material can be obtained in greater purity. In the case of continuous addition, conveying means known to those skilled in the art for liquids or solids can be used (dropping funnel, pump, screw conveyor, etc.). These conveyors can also be used for portion-by-portion addition and dosing preferably fully automatically. On the one hand, the dosing quantity can depend on the batch size. Furthermore, the metering can also be controlled, in particular automatically regulated, based on a measured parameter, for example foam formation, heat development, etc.

In variants, the dosing can also be done by hand. Furthermore, the second substance can also be added in a single dose.

Preferably, during the separation of at least part of the bituminous material from the matrix, a concentration of the second substance, based on a total weight of the mixture, is increased to at most 1.0% by weight, preferably to at most 0.5% by weight. The constant or discrete addition of the second substance to the mixture allows the reaction to be controlled in a range that is optimal for separating off the bituminous material. In this way, in particular, the total amount of the second substance in the mixture can also be optimized, which in turn means that the method can be carried out particularly economically. This is particularly preferably an oxidizing agent, such as a peroxide, in particular hydrogen peroxide.

Depending on the composition of the mixture or depending on the type of bituminous secondary raw material and the second substance used, final concentrations higher than 1.0% by weight can also be provided.

Preferably the second substance is added to the mixture as a solution. This enables a particularly simple and precise dosing. In variants, the second substance can also be added as a solid.

Preferably, a change in concentration of the second substance, based on the total weight of the mixture, is between 10 -2 and 10 -5% by weight per minute, preferably between 10 -3 and 10 -4% by weight. per minute. The change in concentration is preferably controlled in such a way that excessive foaming does not occur. The purity of the bituminous material can thus be increased. It is clear to the person skilled in the art that the change in concentration can also be greater than 0.01% by weight per minute or else less than 10-5% by weight. Here it is important to weigh up the requirements for the quality of the bituminous material and the time required (and thus the cost-effectiveness) of the process.

Gas bubbles are preferably released in the mixture, so that the bituminous material at least partially adheres to gas bubbles and floats to the surface of the mixture.

Bituminous particles that could be detached from the matrix can thus be transported more quickly to the surface of the liquid. Furthermore, the bituminous particles can also be held on the liquid surface with the rising gas bubbles, provided that the density of the liquid is not higher than that of the bituminous material.

In variants, the gas bubbles can also be dispensed with.

The gas bubbles are preferably generated by the second substance, in particular by a chemical reaction. The gas bubbles can thus be generated directly at the point where the bituminous material is detached from the matrix. The bituminous material can thus be detached at the same time as it is transported away via the gas bubbles. This can prevent the bituminous material from sticking to the matrix again immediately after it has been detached. The gas bubbles can be generated, for example, with a separating agent such as a peroxide, with which on the one hand organic compounds can be broken down via the oxygen radicals in order to separate the bituminous material from the matrix and at the same time generate oxygen bubbles through the oxygen formed, which push the bituminous material upwards , carry to the liquid surface. In a further embodiment, the gas bubbles are formed by using sodium bicarbonate, whereby the gas bubbles are formed with carbon dioxide.

In general, the generation of the gas bubbles with the second substance has the advantage that particularly fine gas bubbles can be formed in this way, which efficiently capture the bituminous material and can carry it upwards to the liquid surface.

In variants, the gas bubbles can also be generated in other ways, namely the gas bubbles can also be generated with a pump and/or a separate second container, in particular a pressure container. This can be advantageous in particular when a particularly small amount of the second substance is required to detach the bituminous material, so that too few gas bubbles are generated for the transport of the bituminous material. On the other hand, second substances can also be provided which do not generate gas bubbles; in this case too, a pump or a pressure vessel can be useful for generating the gas bubbles.

The gas bubbles are preferably generated by a chemical reaction, with the second substance in particular comprising a peroxide, a bicarbonate, a percarbonate or a combination of the above. This choice of the second substance enables a particularly efficient formation of gas bubbles in the event of decomposition. Hydrogen peroxide is preferably used because of the low cost and good availability, as well as because of the reactivity. However, it is clear to the person skilled in the art that other second substances can also be used.

The chemical reaction to form the gas bubbles is preferably accelerated by heat and/or by adding a catalyst, preferably iron chloride, iron oxide, ozone, javel water, potassium iodide or a mixture thereof. Decomposition of the peroxide, the carbonate and/or the bicarbonate is preferably accelerated in the process in order to accelerate the separation process overall. In addition to being efficient in terms of time, this also creates a particularly cost-effective method.

By using a catalyst, the decomposition and thus the formation of gas bubbles can be achieved at low temperature. Since a heating process can be dispensed with, the method can be carried out more quickly and energy consumption can be reduced. This in turn allows the costs of the method to be minimized.

The heating also accelerates the decomposition reaction of, for example, peroxides such as hydrogen peroxide or of carbonates, bicarbonates, etc. This also allows the method to be carried out in a particularly short time.

In a further variant, in particular in the case of a more inert second substance, a catalyst can also be used at the same time for heating.

In a further variant, the use of catalysts or heating can also be dispensed with. The second substance can also be excited in other ways to form gas bubbles, in particular by mechanical stress, by microwaves, sound waves, UV light, etc.

In further variants, other peroxides or other separating agents known to those skilled in the art can also be used to generate gas bubbles. As already explained, the gas bubbles can also be generated in some other way, without chemical reactions, for example by a gas pump or the like.

The second substance is preferably metered into the mixture via a first outlet opening below level and a local area around the first outlet opening is heated and/or the catalyst is metered into the local area around the first outlet opening. Local heating means heating part of the mixture to a temperature which is higher than an average temperature of the mixture. The local heating takes place within the mixture. Dosing below the level ensures that the gas bubbles are generated within the mixture and can thus achieve the best possible separating effect as they rise in the mixture. Therefore, the first outlet opening is preferably provided near the bottom of the container. In order to efficiently achieve the formation of gas bubbles in the area of the outlet opening, provision is made for the formation of gas bubbles to be accelerated there by local heating and/or the addition of a catalyst. In this way, an optimal effect can be achieved in the formation of the gas bubbles with a small amount of energy or catalyst.

In variants, the gas bubbles can also be generated outside the container (see below).

In a particularly preferred process, FeCl3 is used as the catalyst. A particularly efficient and at the same time ecologically compatible catalyst is used. However, the person skilled in the art is also aware of other catalysts which could be used here.

The catalyst can also be present in particular as a homogeneous catalyst or as a heterogeneous catalyst, such as iron wire or as a suitable ceramic. A heterogeneous catalyst can, for example, be firmly or detachably connected in the region of the first outlet opening or to the first outlet opening. Furthermore, a heterogeneous catalyst can also be permanently or detachably connected to a container wall, in particular a container bottom and/or container walls. In the preferred embodiment, however, the catalyst is present as a homogeneous catalyst. The catalyst is particularly preferably metered into the mixture in the form of a solution, in particular an aqueous solution or a suspension.

The local area of the first outlet opening is preferably heated with steam and/or hot water. The local heating preferably takes place within the mixture. Accelerated decomposition of the peroxide can thus be achieved without the mixture having to be heated as a whole or without a catalyst having to be used. Optionally, however, a catalyst can also be used in addition. Likewise, the mixture as a whole can nevertheless be heated to a temperature below the local heating temperature. The mixture can thus have a temperature of 30° C. globally, for example, while a temperature of 50° C. or 80° C., for example, prevails locally, in the area of the first outlet opening. The steam and/or the hot water can be used for direct heating, in that the steam and/or the hot water are fed directly to the mixture. In variants, the local area around the first outlet opening can also only be heated indirectly with the steam and/or the hot water, for example by arranging a heating coil (electrical resistance) in this area, for example around the outlet opening or inside the outlet opening.

In variants, the local heating can also be achieved in other ways, in particular, for example, by other types of electrical heating, for example with microwaves, ultrasound, infrared and/or electrical resistance for local heating of the water, etc. Other variants are known to those skilled in the art .

The second substance is preferably metered in via a first tube that encompasses the first outlet opening. The steam and/or the hot water or, alternatively or additionally, the catalyst is preferably metered in via a second outlet opening, in particular a second tube. The first outlet opening and the second outlet opening are preferably arranged close to one another. In this way, the hydrogen peroxide vapor and/or the hot water or the catalyst can be metered in particularly small amounts directly where it is needed, namely at the first outlet opening. The outlet openings can also be arranged in the container, in particular as openings in the bottom area of the container. Furthermore, an outlet opening can also be in a rotary shaft of an agitator or otherwise connected to an agitator. Other options are known to those skilled in the art.

In variants, the second outlet opening can also be dispensed with. The catalyst can also be admixed directly to the mixture, in particular even before the second substance is metered in. Furthermore, a heterogeneous catalyst can also be provided, which is provided in a stationary manner in the region of the first outlet opening. Other variants are known to those skilled in the art.

In a preferred method, the first tube and the second tube are routed coaxially. This creates a technically particularly simple device, with which the second substance can be brought together with the catalyst, the hot water and/or the steam below level. In the preferred embodiment, the superheated steam and/or the hot water is conducted in the outer tube (in the outer tube here means between the inner tube and the outer tube), while an aqueous solution of the second substance, in particular a peroxide, is conducted in the inner tube. In variants, however, the superheated steam and/or the hot water can also be routed in the inner tube, while the second substance is routed in the outer tube. In particular when hot water and/or superheated steam is used, the coaxial pipe routing is of particular advantage since the second substance can already be preheated inside the pipe. The formation of bubbles can thus be further optimized. In particular, the formation of bubbles can already be achieved within the first tube.

In variants, the first tube and the second tube can also be routed separately. This can be advantageous in particular when the second substance is highly reactive. Furthermore, the second tube can also open into the first tube at the side. In this way, for example, the catalyst or the hot water/hot steam can be fed into the first tube of the second substance. The first tube can also include static mixers, which optimize thorough mixing of the first substance with the catalyst or the hot water/hot steam. With this, an amount of the catalyst can be further reduced.

An average temperature of the liquid during the process is preferably below 60°C, preferably below 40°C, particularly preferably below 30°C, particularly preferably at room temperature. The choice of such an average temperature has the advantage that relatively little heat energy has to be used, which on the one hand avoids a lengthy heating-up process and on the other hand saves energy. The specific selection of the average temperature can be made depending on the second substance used, in order to control a reaction rate. In particular when using a reactive second substance to generate gas bubbles, the method can be carried out at a relatively low average temperature. If additional catalysts are used or if the second substance is added locally according to the above description, the average temperature can tend to be kept lower. In variants, the temperature can also be selected higher than 60 °C (see below).

In a preferred embodiment of the method, a catalyst in an aqueous solution is placed in the second container. A substance that generates gas bubbles, preferably a peroxide, particularly preferably hydrogen peroxide, a carbonate, a percarbonate or a combination of the above, is metered into the second container via a first feed line. A gas formed in the second container is fed below level into the first container via a connecting line. In this variant, the gas bubbles can be generated with a particularly small amount of a catalyst. Iron(III) chloride is preferably used as the catalyst, but alternatively iron oxide, ozone, Javel water, potassium iodide or a mixture thereof can also be used. In principle, the catalyst can also be dispensed with. In this case, the second container may be heated, for example, so as to accelerate decomposition of the gas bubble generating substance. Other methods are known to those skilled in the art.

The gas bubbles can also be achieved by a mixing process or a stirring process. With such a mixing process, grinding effects can be achieved at the same time, which can promote the separation of the bituminous material.

In a particularly preferred embodiment of the method, after the abrasion process, the bituminous material, which is still contaminated with sand, grit and filler, is mixed with water and mixed. This allows sand, chippings and filler to be separated from the bituminous material. Other methods can also be used in variants. The mixing process is preferably carried out in such a way that air bubbles are introduced into the suspension. This can be achieved analogously to a household mixer by stirring so vigorously that a deep vortex is formed, with which air can be introduced into the suspension. The bituminous material can be carried to the surface with the rising air bubbles and discharged, for example, via a sludge suction device. In variants, the bituminous material can also be separated in other ways. The air bubbles or gas bubbles can also be generated chemically or generated using a pump or the like.

Finally, the generation of gas bubbles can also generally be dispensed with. In this case, the transport of the bituminous material to the liquid surface can also be ensured by convection, a flow course, by density differences between the bituminous material and the liquid, etc.

Furthermore, the bituminous material could also be carried upwards by apolar droplets of a first substance with a lower density than that of the polar liquid. The apolar droplets can be produced with an alkane, a water-insoluble alcohol, etc., for example. For example, the drops can be introduced in the form of an emulsion in the bottom area of the container. Finally, further possibilities are known to the person skilled in the art.

Finally, both gas bubbles and apolar liquid droplets can be dispensed with. The bituminous material, provided its density is greater than that of the liquid, can also be discharged in the bottom area of the container. Further, the bituminous material can be filtered, sieved, decanted, etc. from the liquid. Many other techniques are known to those skilled in the art.

The gas bubbles preferably comprise ambient air, oxygen, nitrogen and/or carbon dioxide. Oxygen and carbon dioxide in particular can be generated particularly easily using chemical means. All gases are also inexpensive to produce. Ambient air is particularly preferably used if a pump is used, since this is freely available.

However, other gases for generating the gas bubbles are also known to those skilled in the art. In particular, noble gases, hydrogen, etc. can also be used. In principle, gaseous or vaporized organic substances can also be used. At the same time, the density of the bituminous material can be reduced, which can promote floating on the liquid.

In a further preferred variant, the mixture is heated, in particular directly and/or indirectly, preferably with warm water, hot water and/or steam. The detachment of the bituminous material from the matrix can be accelerated by heating. Any chemical reactions, caused in particular by the second substance, can also be promoted. This accelerates the overall separation process. The time saved means that production can be carried out more economically. In a first variant, the container can be heated directly. The heating can take place directly, by preheating the liquid, by introducing superheated steam into the mixture, or via an outer wall of the container. Other variants are known to those skilled in the art.

In variants, it is also possible to dispense with heating the mixture. In particular in a process in which the secondary raw material has previously been subjected to an abrasion process, tests have shown that heating can be dispensed with, in particular from an economic and ecological point of view - it is clear to the person skilled in the art that heating can nevertheless typically benefit the process. In particular, it was recognized that the process with the secondary raw material, which was obtained from a abrasion process from road surface material, namely the abrasion, can be carried out particularly ecologically and economically by adding water exclusively to the abrasion and mixing it at room temperature in such a way that air the suspension is introduced, which rise to the liquid surface as air bubbles together with the bituminous material. There, the bituminous material, for example in the form of a foam, can be sucked off with a mud vacuum cleaner. However, it is clear to the person skilled in the art that the process could also be made more efficient by chemical additives, by heating, etc.

In further variants, other means, for example microwave energy, electrical energy, fuels, in particular, for example, parts of the bituminous material, etc., can also be used. In case of incineration of parts of the bituminous material, especially e.g. B. a fraction of the bituminous material, electrical energy can be produced with the excess heat, which can be used for the process or otherwise.

In a further preferred variant, the mixture is heated to a temperature above 50.degree. Increasing the temperature of the entire mixture requires more energy, but the process can be carried out in a shorter time. Experiments have shown that the process works well above 50 °C. Temperatures above 80 °C are ideal, in particular above 90 °C, for example up to 100 °C. Depending on the type of secondary raw material and the addition of additives such as the peroxides, carbonates, bicarbonates etc. described above, the process can also be carried out at temperatures below 50 °C or the mixture can only be heated locally (see above). Depending on the second substance used, particularly when using hydrogen peroxide, a lower temperature can possibly prevent an overreaction. Here, a trade-off can be made between the temperature of the mixture and the addition rate (change in concentration) of the second substance, with the addition rate typically being able to be lowered at higher temperatures.

The mixture is preferably mixed mechanically, in particular to maximize yield. With the mixing, the bituminous material can also be loosened mechanically on the one hand. Furthermore, a chemical reaction caused by the second substance can thus be implemented more quickly. Overall, this also speeds up the process itself. This preferably also increases the yield of the bituminous material.

In variants, the mechanical mixing can also be dispensed with.

The mixture is preferably treated with physical means, in particular with sound, ultrasound and/or microwaves. The detachment process of the bituminous material from the matrix can also be optimized in this way. To this end, it is advantageous if the frequency is set in such a way that bituminous droplets or particles are optimally excited. The frequency is therefore preferably chosen to be less than 200 kHz, particularly preferably less than 100 kHz, in particular less than 50 kHz. It may also be useful to stimulate microscopic particles, for example those to which the bituminous material adheres. In this case, frequencies above 200 kHz can also be provided.

In variants, the physical means can also be dispensed with.

The process is preferably carried out batchwise. For this purpose, a quantity of the secondary raw material, in particular road surface material, is placed in a container and covered with the liquid, in particular water. The bituminous material that accumulates on the water surface is skimmed off, preferably continuously. In variants, the process can also be carried out continuously. For this purpose, the secondary raw material can be conveyed into a container with conveying means, for example via a conveyor belt, and continuously discharged from the container again via a screw conveyor. Techniques for optimizing the residence time of the secondary raw material in the container are known to those skilled in the art.

The method is preferably carried out as ecologically and economically as possible. The environment is thus less polluted and the process can be carried out relatively inexpensively.

After the separation of the bituminous material, the liquid, in particular the water, is preferably processed for reuse in the process, in particular for a next batch. The processing of the liquid can be designed in such a way that the requirements for reuse in the process are met. If, for example, table salt is dissolved in the water to increase its density, this does not have to be removed from the water during treatment. Typically, running the water through a settling tank or centrifuging with a cyclone to remove suspended solids may be sufficient. In variants, the preparation can also be dispensed with entirely, especially if the impurities do not have a negative effect on the process. In this case, the liquid can be directly reused in the process or disposed of.

Process heat is preferably recovered with one or more heat exchangers. This is preferably recovered from the liquid, in particular the water. Appropriate techniques are sufficiently known to those skilled in the art. The recovered heat can be used directly to preheat the liquid for the process or otherwise (for space heating, hot water boilers, etc.).

In variants, the heat recovery can also be dispensed with.

The bituminous material is preferably skimmed off continuously or discontinuously at the liquid surface, in particular in the form of a foam. In particular in a variant in which gas bubbles are generated, a foam is typically generated on the liquid surface, in which the particles of the bituminous material are located. This foam can be caught off the surface of the liquid with a sword. Furthermore, the foam can also be driven in the direction of an overflow by a suitable stirrer. Further variants are also known to the person skilled in the art.

In variants, the bituminous material can also be discharged from the mixture via a sludge suction device or in some other way (see above). The use of a sludge vacuum has the advantage that it is positioned between 1 and 100 mm above the water surface, which means that agitated sand or filler is discharged to a lesser extent. Bituminous material with higher purity is thus obtained.

Preferably, the bituminous material is subjected to a further cleaning step after separation from the matrix. After the separation process, the bituminous material may contain impurities, in particular sand, fillers and additives. The separation can be carried out using techniques known to those skilled in the art.

Depending on the use, the bituminous material can also be used directly after the separation process for the production of, optionally specific, asphalt coverings in which the foreign substances in the bituminous material do not interfere or are even desired.

The bituminous material is preferably suspended in a liquid, in particular in water, and mixed or mixed in order to separate filler, sand and other substances from the bitumen. For this purpose, the bituminous material can be subjected to a grinding process beforehand--whether the grinding process is used can depend on the desired purity or the grain size of the bituminous material, etc. The grinding process can also be omitted. A liquid is particularly preferably used which, on the one hand, has a higher density than the bitumen and, on the other hand, has a lower density than the filler or sand and chippings. In this way, an optimal separation within the liquid can be achieved in such a way that the bitumen rises to the surface of the liquid and the filler, sand, grit and possibly other materials with a higher density collect on the bottom of the container. The liquid preferably comprises water in which a first substance that increases the density is dissolved (see above). Influencing the density can also be dispensed with. The separation can also be achieved by choosing a suitable flow, whereby parts with a lower density (bitumen) can be separated from parts with a higher density (filler, sand, etc.). For this purpose, for example, a current generated by an agitator, in particular a buoyancy, can be provided. This further cleaning step is preferably carried out without chemical additives. Experiments have shown that, particularly in the case of bituminous material obtained from road surface material by the method, the second substance (release agent, see above) can generally be dispensed with in this further cleaning step. This further cleaning step can thus be carried out particularly economically and ecologically. Even if road surface concentrate containing bitumen is used, which has been mechanically concentrated (through the abrasion process), a release agent, i.e. the second substance, can possibly be dispensed with. Intensive mixing allows more air bubbles to be introduced into the suspension, which in turn can improve the separating effect. This will pick up air bubbles, which in turn will create a bituminous slurry or foam that contains less sand and filler.

In variants, after separation from the matrix, the bituminous material can be separated from foreign bodies, in particular from filler and sand, by centrifuging or using a centrifugal separator (cyclone). This means that the bituminous material can again be used universally for the production of asphalt pavements. The separation does not necessarily have to be carried out by centrifugation; other techniques are also known to the person skilled in the art.

In variants, it is also possible to dispense with the separation of the foreign bodies.

The secondary raw material preferably runs through the process several times in order to achieve a greater separation efficiency. In this way, on the one hand, a higher yield of bituminous material can be achieved. On the other hand, the sand and grit can be cleaned better, which means that they can also be used again. Furthermore, the process can also be repeated with the separated bituminous material, with which filler and sand can be further removed from the bituminous material in order to achieve greater purity of the bituminous material.

In variants, the second run can be dispensed with, in particular if the first process run was sufficiently efficient.

The process is preferably carried out under reduced pressure. In this way, in particular, a method in which the bituminous material is carried to the surface of the liquid with gas bubbles is favored or accelerated.

In variants, it is also possible to dispense with carrying out the method under reduced pressure.

The secondary raw material preferably includes chippings, sand and filler. These components are found in particular in road surface material, but can in principle also be found in other secondary raw materials.

In particular in the production of road surface material, the aim is to select the components and to process them in such a way that the bituminous material adheres to the matrix in the best possible way. For this purpose, fillers or adhesion promoters are usually used. In principle, these additives make it more difficult to detach bituminous material from the matrix—however, the present method has surprisingly shown that, despite these aggravating circumstances, road surface material can also be separated into bituminous material and matrix.

In variants, the secondary raw material can also include no grit, no sand and/or no filler.

The secondary raw material preferably has a water content of less than 5% by weight. %, particularly preferably less than 1 wt. %, particularly preferably less than 0.1 wt. %. Here, too, the low water content is fundamentally disadvantageous for the separation of the bituminous material from the matrix. A higher water content typically favors the separation of the bituminous material, especially since the bituminous material is non-polar and the water is polar. However, it has surprisingly turned out that the method is nevertheless suitable for separating the bituminous material even in the case of secondary raw materials with a particularly low water content.

In variants, the water content of the secondary raw material can also be higher than 5% by weight.

In a preferred embodiment of the method, the secondary raw material is preferably present in the form of fragments, with at least a proportion of 10% by weight, preferably at least 20% by weight. % of fragments with a minimum diameter of more than 10 mm.

Here, too, in principle, a larger fragment size is typically disadvantageous for the separation process. However, experiments have surprisingly shown that the secondary raw material does not have to be comminuted as small as desired in order to be able to carry out the process efficiently.

Particularly in the case of demolition material in road construction, the fragments can be very large immediately after the road has been demolished. These must be crushed to carry out the process. However, the size of the fragment does not have to be arbitrarily small, but can have a size of up to 80 mm or more. The method can thus be carried out inexpensively. Furthermore, this can prevent the split and sand from being destroyed, which means that these materials can also be reused after separation.

In variants, however, the fragments can also be smaller or present in the size indicated above with a smaller proportion of the total mass. The fragments can also be broken, ground or otherwise comminuted into smaller particles.

Preferably at least 20% by weight, preferably at least 30% by weight, particularly preferably at least 40% by weight, of the matrix has a particle size of more than 5 mm. The above also applies here, according to which, in principle, large grain sizes are disadvantageous for the process, but the present process has proven to be surprisingly efficient even with large grain sizes.

In variants, less than 20% by weight of the matrix can also have a particle size of more than 5 mm.

The secondary raw material preferably comprises one or more of the following components: polymers, reinforcing fibers, in particular cellulose fibers and/or aramid fibers, hydrated lime, juvenators. Such additives or components are typically used in asphalt pavements. Polymers and hydrated lime in particular are typically found in asphalt pavements. These additives ensure that the bituminous material adheres particularly well to the matrix material, in particular chippings and crushed sand. The present method proved to be efficient even under these circumstances, which aggravated the separation.

[0126] None of the components are necessary for carrying out the method. However, it could be shown that the process also works if some or all of these components are present in the secondary raw material.

The proportion of hydrated lime in the secondary raw material is preferably between 0.5 and 3% by weight, preferably between 1 and 2% by weight. In variants, the proportion of hydrated lime can also be higher than 3% by weight or lower than 0.5% by weight.

The proportion of polymers in the bituminous material is preferably at least 2% by weight, particularly preferably at least 4% by weight. %, in particular between 5 and 7% by weight. In variants, the proportion of polymers can also be below 2% by weight or above 7% by weight.

The secondary raw material preferably has a density between 1.2 g/cm 3 and 2.6 g/cm 3 , preferably between 1.4 g/cm 3 and 2.4 g/cm 3 . In variants, the density can also be less than 1.2 g/cm3 or greater than 2.6 g/cm3.

A proportion of VOC or VVOC in the secondary raw material is preferably less than 0.1% by weight. %, preferably less than 0.01 wt. %. VOC and VVOC are volatile organic compounds. In the present case, VVOC includes organic compounds with a boiling range with an upper limit of 100 °C. VOCs include organic compounds with a boiling range between 100 °C and 260 °C. The VOC or VVOC are helpful for separating bituminous material from the matrix, since they are also non-polar and thus serve as solubilizers for the bituminous material. The surface of the bituminous particles is dissolved by the VOC or VVOC, which can reduce the holding power to the matrix. However, it has now been discovered that the present method can also be used to separate bituminous material from a matrix that contains little or no VOC or VVOC.

In the production of the asphalt, the bituminous material in the paving material is typically applied at a temperature of 120°C to 230°C to sand, chippings, etc., which have been preheated to 400°C (other parameters are also possible). This means that a large part of the VOC or VVOC is already volatilized during the production of the asphalt. Residual amounts of volatile organic compounds diffuse out of the pavement over the course of time, so that this typically contains practically no more volatile organic compounds in the case of an upcoming renovation. It is now particularly important to note that the extensive absence of lighter oils, i. H. of VOC or VVOC, the (old) road surface material lacks a solubilizer that would help to separate the bituminous material from the matrix. Surprisingly, with the present method, the bituminous material can now be detached from the matrix in an efficient manner even in the absence of VOC or VVOC.

In variants, the method can of course also be applied to secondary raw materials which have a higher proportion of VOC or VVOC than 0.1% by weight.

The bituminous material in the road surface material preferably has less than 0.1% by weight, preferably less than 0.01% by weight, of distillable petroleum components or hydrocarbons. Surprisingly, it has been shown that the process also works well when the distillable petroleum components or hydrocarbons are very small - the process can therefore also be carried out efficiently to a large extent without solubilizers.

In variants, the proportion of distillable petroleum components or hydrocarbons can also be higher than 0.1% by weight.

A kinematic viscosity at 60° C. of the bituminous material is preferably higher than 400 mm 2 /s, preferably higher than 1000 mm 2 /s. The kinematic viscosity of the bituminous material in the secondary raw material is particularly preferably higher than 5000 mm 2 /s, particularly preferably higher than 10 000 mm 2 /s. When using the present method, the kinematic viscosity can even be higher than 25,000 mm 2 /s. Such kinematic viscosity values are typically achieved in bituminous material in old paving material. Here too, in principle, a high kinematic viscosity of the bituminous material stands in the way of efficient separation of the matrix—surprisingly, bituminous material with a very high kinematic viscosity can also be separated from the matrix with the present method.

Here, too, it is clear to the person skilled in the art that the method can also be carried out at a kinematic viscosity of less than 400 mm 2 /s.

A density of the bituminous material is preferably greater than 1000 kg/m 3 , preferably greater than 1010 kg/m 3 . Along with the viscosity and the low content of volatile organic compounds, the density typically increases with bituminous material. Experiments have shown that even with a density of the bituminous material that is higher than that of water, separation from the matrix is possible and, in particular, economically feasible. It could even be shown that a separation at the water surface can be achieved, in particular, for example, in a process in which gas bubbles are generated in the mixture. However, the method can also be carried out with a secondary raw material in which the bituminous material has a lower density than water, ie less than 1,000 kg/m 3 .

The bituminous material preferably has a softening point of more than 50.degree. C., in particular more than 70.degree. C., particularly preferably more than 90.degree. The softening point of the bituminous material in a pavement typically increases with age. In variants, the softening point can also be less than 50°C.

The bituminous material preferably has a penetration (needle) at 25° C. of less than 5×10 −1 mm, preferably less than 3×10 −1 mm, in particular less than 1×10 −1 mm . The penetration value of the bituminous material in a pavement typically decreases with age. In variants, a penetration of the bituminous material can also be more than 5 10<-1>mm.

The bituminous material obtained by means of the method, which has been separated from a secondary raw material, is preferably used for the production of asphalt. If the secondary raw material already includes asphalted road surface material, the advantage is that it is not necessary to remove any impurities from the bituminous material, since they would be returned to the asphalt anyway. This creates a particularly economical reuse of bituminous material from road surface material. However, other uses of the recycled bituminous material are known to those skilled in the art (see above). If necessary, the bituminous material can also be processed or cleaned.

A device for carrying out the method essentially comprises a container into which the liquid and the secondary raw material can be added. In a preferred embodiment, the container can taper towards the container opening. This has the advantage that the floating bituminous material lies on a smaller surface and can therefore be skimmed off in higher concentrations. There is also the advantage that the secondary raw material can be covered with a smaller amount of liquid. The method can thus be carried out overall with a smaller volume. Another advantage is that there is less movement of the liquid surface during stirring, which can also prevent the separated bituminous material from coming into contact with the secondary raw material below the liquid surface and adhering to it again. In variants, the container can also do without the taper.

In a further preferred embodiment, the device for carrying out the method comprises a log washer or an Archimedes screw, with which the bituminous secondary raw material can be transported through the liquid and discharged.

Preferably, the separation process is monitored with sensors. Monitoring can be performed online, continuously or discontinuously.

[0144] Continuous monitoring can be done, for example, through the use of sensors which are in contact with the mixture during the process. Discontinuous monitoring can be carried out, for example, by taking regular samples, which are analyzed in each case. Many suitable sensors that can be used to monitor the process are known to those skilled in the art. On the one hand it can be used to monitor primary factors such as the effective separation of the bitumen from the matrix, which can be used to determine, for example, when the separation process is complete (whether the gravel/sand is clean). This allows optimizing the residence time of the materials in the reactor as well as optimizing the amount of substances to be added, such as bicarbonates, peroxides, etc.

Alternatively or additionally, secondary factors such as temperature, density, pH, conductivity, refractive index, etc., as well as rates of change thereof, and the like can also be monitored. In a preferred embodiment of the method, a first and/or second substance is added on the basis of the values measured with the sensor. The process can thus be carried out particularly efficiently and with optimized use of resources (energy, time, additives, etc.).

[0146] In variants, the monitoring with sensors can also be dispensed with. In this case, the process can also be monitored visually.

The sensor preferably comprises an optical sensor, in particular a UV-Vis fluorescence sensor, X-ray fluorescence sensor, Raman spectroscopy sensor, image recognition photography, NIR, etc. Other sensors known to the person skilled in the art can also be used in variants. In particular, a combustion test with detection of combustion gases can also be carried out during sampling (e.g. by optical spectroscopy (NIR or other) etc.

[0148] Further advantageous embodiments and combinations of features of the invention result from the following detailed description and the entirety of the patent claims.

Brief description of the drawings

The drawings used to explain the exemplary embodiment show: FIG. 1 a schematic representation of a vertical section through an asphalt layer; Fig. 2 is a schematic representation of a vertical section through broken asphalt; 3 shows a schematic representation of a vertical section through milled asphalt; 4 shows a schematic representation of a vertical section through a container with a mixture; 5 shows a schematic representation of a vertical section through a container during the separation process; Fig. 6 shows a schematic representation of a vertical section through a container during the separation process in greater detail; 7 shows a schematic representation of a vertical section through a device for continuously carrying out the method; 8 shows a schematic representation of a first embodiment of a device for carrying out the method with a device for generating gas bubbles; 9 shows a schematic representation of a second embodiment of a device for carrying out the method with a separate reactor for generating gas bubbles; 10 shows a schematic representation of a third embodiment of a device for carrying out the method, in which the bitumen is skimmed off at the liquid surface; and FIG. 11 shows a schematic representation of a fourth embodiment of a device for carrying out the method, the bitumen being collected and discharged at the bottom of the container.

In principle, the same parts are provided with the same reference symbols in the figures.

Ways to carry out the invention

1 shows a vertical section through an asphalt layer 100. This includes aggregates 101, which more or less large pebbles, sand 102, filler 103 and bituminous material 104 includes. The roadway is on the surface 105. With increasing wear, the aggregates 101 are rounded off, making the road slippery and requiring rehabilitation. The road surface is either milled off or broken off.

FIG. 2 shows a vertical section through a broken layer of asphalt. The fragments 106 are relatively large and still include a large number of sand particles and several pebbles 102.

FIG. 3 shows a vertical section through a milled asphalt layer. The particles of the milled material 107 are far smaller than those of the broken pieces of asphalt in FIG. 2. A particle 107 now also includes one or a few pebbles. The proportion of dust is increased by the milling process, which typically means that the bituminous material is enriched with dust during the cutting process.

FIG. 4 shows a vertical section through a container with a mixture. The mixture includes an aqueous solution 108 and fragments 106 of the road surface according to Figure 2.

FIG. 5 shows a vertical section through a container during the separation process. The fragments 106 have already dissolved into bituminous material and the matrix. The pebbles 101 and the sand 102 collect on the bottom, while the bituminous material detached from the matrix collects in the foam 109.

FIG. 6 shows a vertical section through a container during the separation process in greater detail. The pebbles 101 and sand 102 collect at the bottom of the container during the process. In the present case, a mixer 110 is provided in the container, with which the mixture can be circulated. The efficiency of the method can thus be increased. With a skimming system 111, for example a sludge sucker, the foam that forms and with it the bituminous material separated from the matrix is continuously skimmed off. Furthermore, a heat source 112 is arranged under the container, with which the mixture can be heated during the process. A reactive substance, in particular a separating agent such as a peroxide, can be supplied with a pipe 114 in such a way that it reaches the asphalt directly. The peroxide can thus be brought close to the asphalt continuously or by successive additions, thus being used effectively to separate the bituminous material from the matrix.

FIG. 7 shows a vertical section through a device for continuously carrying out the process. The device includes an entry for the bitumen-containing secondary raw material 104. This is conveyed diagonally upwards via an Archimedes screw along a container, through the aqueous solution 108 and finally discharged from the container via an overflow. A sword washer can also be used instead of the Archimedes screw.

The experiments conducted on the separation method are described below. Milled material from a road surface was used as a secondary raw material in the following experiments.

In a first test, 5 g of milled material from a road surface were broken up and mixed with 10 ml of 3% hydrogen peroxide in a container. The container was placed in a pressure cooker containing water and boiled for 5 minutes. A foam with 1 g dry mass, including bitumen and filler, was found on top of the hydrogen peroxide solution in the container.

In a second test using a water bath heating system, 300 g of road surface millings were broken up and placed in a beaker. 500 ml of a 3% hydrogen peroxide solution were added to the milled material. The beaker was heated to 60 to 65 °C in a water bath. Bubbles formed, which carried the bitumen to the surface, where foam formed. When increasing the temperature to 80 °C the process was more efficient, at 95 °C the separation proceeded for 10 minutes under very good conditions, achieving a good separation of the bituminous material from the matrix.

In a third test, 6.8 kg of road surface millings were broken up and placed in a container. The milled material was covered with water. The mixture was then heated to 60° C. and 100 ml of 35% hydrogen peroxide solution were added. The mixture was stirred and the foam skimmed off at regular intervals. After four hours of skimming and adding hydrogen peroxide (every 30 minutes), the process was stopped. The matrix could be almost completely freed from bituminous material. The matrix weighed 4.1 kg and the bituminous material weighed 1.6 kg. Fine residues in the water made up the rest of the milled material. Since the road surface only comprises around 6% bituminous material, there are only around 400 g of bituminous material in the 1.6 kg, the rest is likely to be filler, dust, fragments, etc. The large amount of fine aggregates is due to the breaking of the milled material.

In a fourth test, a block of 3.8 kg of milled material from a road surface was used. This was broken into pieces 40 to 80 mm in diameter. The fragments were covered with water in a container and heated to a temperature of 60°C. 160 ml of 35% hydrogen peroxide solution were added continuously over a period of 2.5 hours. The foam was regularly skimmed off. The mixture was boiled. The remaining matrix was bitumen-free and weighed 2.9 kg. The bituminous material weighed 0.7 kg, with the filler accounting for 165 g. The theoretical amount of bituminous material is 230g, with filler and dust accounting for 228g - around 6% of the original amount of milled material.

These experiments have shown that the crushing process can have the disadvantage that dust accumulates in the bituminous material. Bituminous material with greater purity can thus be obtained by using fragments of road pavement directly.

In a fifth experiment, on the one hand, the density of water was increased in order to increase the buoyancy of the bituminous material in the water. Bituminous material in road surfaces typically has a higher density than water, namely between 1.01 and 1.05 kg/L. There is therefore a risk that the bituminous material will collect at the bottom of the container after it has been detached from the matrix. This effect can be counteracted by adding a density-increasing salt or a density-increasing liquid. Sodium chloride, magnesium chloride, potassium chloride, sodium carbonate or sodium nitrate can be provided as salts. For example, glycerin or the like can be used as the liquid. The separation can also take place in pure glycerol.

In a sixth test, 5 kg of milled material from a road surface were used and mixed with 7.5 l of water without common salt. The mixture was heated to 95°C and stirred with a paddle mixer. 100 g of sodium bicarbonate in powder form were then added every 15 minutes. After 6 additions and a reaction time of 2 hours, 1.3 kg of bituminous material were recovered at the water surface. The 3.7 kg matrix was largely separated from the bituminous material. The water contained suspended matter.

These experiments show that the process can be carried out with different substances (bicarbonates, acetic acid, peroxides, percarbonates, etc.).

In a seventh experiment, 5 kg of milled material was mixed with 5 liters of water and rubbed with a powerful mixer for two hours (attrition method, see above). After two hours, the grit (gravel) were examined. The grit contained some bitumen in the concave areas. The abrasion contains the majority of bitumen.

About 10% by weight of CaCl 2 was then dissolved in 600 ml of the above residual water, which contained filler and sand with bituminous material, and 1 ml of 35% by weight of H 2 O 2 was added and the mixture was heated. A bituminous residue was extracted and the sand and filler were decanted. After 24 hours this part represented 180 ml and no longer contained any bitumen. 200 g of chippings containing a little bitumen were treated again in 600 ml of water with 1 ml of H2O2 and heated. After treatment, the chippings were cleaned of bitumen.

In a further experiment, 300 ml of water were added to 400 ml of the above residual water, which contained filler and sand with bituminous material, and mixed in a mixer (which is also used for mixing smoothies). Mixing creates many air bubbles in the suspension, which carry the bituminous material to the surface in the form of a foam. Sand and filler, on the other hand, sediment due to their higher density. The process works without chemical additives and also without additives to increase the density of the water.

[0170] These variants show that it is possible to combine different techniques (attrition, fractionation, etc.) to achieve the best efficiency (efficiency, purity, etc.).

In an eighth experiment, approximately 80 kg of milled material were heated and mixed in 200 L of water at 90°C. During the procedure, 10 mL/min H2O2 was injected by pump. To increase the density of the water, 25 kg of sodium carbonate was added. After two hours of reaction, 10 kg of bituminous residue and 70 kg of mineral matter were collected. This showed that cleaning can also be carried out without a chloride salt.

In a ninth experiment, 10 kg of milled material were heated in 20 L of water and sodium bicarbonate. The bituminous material rose to the surface but fell back down because the difference in density was insufficient to keep the bituminous material on the water surface. To recover the residue on the water surface, a flow of carbon dioxide (CO2) was introduced at the bottom of the tank, causing the bituminous material to convect to the surface where it could be collected. This experiment shows that it is possible to collect the bituminous residues on the liquid surface without increasing the density of the water with salt or sugar.

In a tenth experiment, the dried bituminous material was post-processed to extract the bitumen from the filler and sand. In fact, the bituminous residue may contain 25% to 33% by weight of bitumen, with the remainder comprising small mineral particles. The bituminous material was placed in a container with water and finished by mixing vigorously with a mixer. This separated the bitumen from the filler and the sand. By adding salt to the water, the bitumen floated to the surface while the mineral part settled. This allowed the bitumen to be concentrated.

In the case of road surfaces, the bituminous material deliberately adheres particularly strongly to the fillers, to the sand and grit. A layer thickness can reach several hundred microns. As a result, the bituminous material is removed layer by layer from the matrix during the process. This in turn means that rapid addition of a reactive substance, in particular a separating agent such as a peroxide, can have the following disadvantages: too violent a reaction is triggered, producing a large amount of foam. With the gas bubbles, not only the bituminous material, but also a lot of sand and filler is carried up into the foam; the peroxide can also react with already separated bituminous material, thus oxidizing the bituminous material. Thus, the peroxide is used inefficiently.

[0175] These problems can be tackled with two measures. On the one hand, the peroxide can be added in doses so that a low concentration is present in each case. It is also advantageous if the peroxide in the area of the secondary raw material, i. H. is supplied in the region of the bottom of the container. This can be done, for example, via a dip tube.

In this fifth test, 280 kg of milled material from a road surface were used and 250 l of water and 25 kg of common salt were added. The mixture was heated to 60°C and stirred with a paddle mixer. Then, after 10 minutes, 100 ml of 35% hydrogen peroxide solution were added via an immersion tube. Alternatively, the addition can also take place continuously via a pump. After 14 additions of 100 ml hydrogen peroxide solution at 35% each and 2 hours reaction time as well as 1 hour material collection, 45 kg bituminous material were recovered at the water surface. The matrix was largely separated from the bituminous material. The salt water contained suspended matter.

The mode of operation has not been fully clarified. It is possible that the introduction of the peroxide solution will result in a relatively acidic pH, dissolving limescale and releasing bicarbonate. The bicarbonate in turn acts together with peroxide as a powerful cleaning agent which in turn can effectively separate the bituminous material from the matrix.

In a further preferred method, the use of catalysts accelerates the formation of gas bubbles, with which the temperature of the mixture in the container can be kept lower. This saves on the one hand the heating-up time and on the other hand the heating energy. A particularly efficient and cost-effective separation process is thus achieved.

FIG. 8 shows a schematic representation of a first embodiment of a device 200 for carrying out the method with a device for generating gas bubbles. The device 200 includes a container 210 in which the milled material is mixed with the water. The device 200 also includes a first dosing container 220, in which hydrogen peroxide (alternatively, other substances, in particular other peroxides, carbonates or bicarbonates, etc., can also be provided) is placed in an aqueous solution. The solution is metered into the container 210 via a line 221 . A catalyst, in this case iron(III) chloride, is placed in an aqueous solution in a second metering container 230 . This catalyst solution is metered into the container 210 via a separate line 231 . The solutions are metered in each case via a pump (not shown). The lines 221 and 231 open side by side below the level in the container 210, so that immediately after the exit of the catalyst solution and the hydrogen peroxide solution, a decomposition reaction takes place, with which gas bubbles are generated, which bring the bitumen to the surface. The two lines 221 and 231 can end in a static mixer or the like for better mixing. A paddle mixer (not shown) is also provided within hopper 210 to agitate the milled material during the process.

In a further embodiment, the catalyst is mixed with the water directly in the container, which means that the line 231 can also be dispensed with.

The materials (milled material, catalyst, etc.), which are suspended or dissolved in the water, can be introduced with different technical devices, for example with scrapers, vibrators, inclined planes, mixers, inclined rotating drums, conveyor belts, screw conveyors, etc.

In a further embodiment of the method, instead of the catalyst solution, superheated steam is fed via line 231 into the local area of the outlet opening of line 221 . With this, a substance that generates gas bubbles, for example the peroxide, can be heated locally in order to accelerate the decomposition.

In another embodiment, a catalyst solution is heated, whereby the decomposition reaction is accelerated by heat and the catalyst at the same time. This embodiment can be used with substances that are typically less reactive.

While the two lines 221 and 231 are routed in parallel in the first embodiment, in a further embodiment they can also be designed coaxially, as an inner tube and outer tube. Furthermore, the pipelines—whether parallel or coaxial—can also be connected from an outside of the container 210 to openings in the bottom of the container. This can be of advantage, since a stirring process in the container 210 is not impeded by lines. Furthermore, the lines can also end in a common tailpipe.

FIG. 9 shows a schematic representation of a second embodiment of an apparatus for carrying out the method with a separate reactor for generating gas bubbles. The device in turn comprises a container 310 in which the bituminous material, in this case bituminous milled material, is mixed with water. Hydrogen peroxide in an aqueous solution is placed in a first metering container 320 and a catalyst solution, in this case iron(III) chloride, is placed in a second metering container 330 . The second dosing container 330 is connected to the first dosing container 320 via a line 331 . The catalyst solution can thus be metered from the second metering container 330 into the first metering container 320 via a metering unit (not shown). A catalytically accelerated decomposition of the hydrogen peroxide thus takes place in the first dosing container 320, with the result that oxygen is formed. This is transferred via the line 321 from the first dosing container 320 to the container 310 below level. Instead of a catalytic decomposition in the first metering container 320, the decomposition in the first metering container 320 can also be accelerated by heating.

In a first test, 30 kg of milled material are placed in a container with an agitator containing 40 L of water at 18°C. 4 kg of Na2CO3 are added to obtain sufficient density for the bitumen extract to float on the water after separation. Two tubes are connected in parallel to dose a 35% H2O2 solution and a 40% FeCl3 solution at a flow rate of 100 microliters/minute. Even at low temperatures, the mixture of the two reagents generates gas bubbles that result from the decomposition of the peroxide. After two hours, a bituminous extract weighing several kilograms is collected and dried in powder form. The remaining material consists of sand and pebbles cleaned of their bitumen. A brown residue of oxidized iron is also visible, but this can be easily rinsed out. The water temperature only rises to around 22°C during the reaction due to the endothermic nature of the peroxide decomposition.

In a further experiment, the decomposition of peroxide was accelerated by local heating: around 30 kg of milled material are mixed with 40 L of water at 15° C. in a reactor with an agitator. 4 kg of Na2CO3 are added to obtain sufficient density for the bitumen extract to float on water after separation. Two tubes are plugged into each other. A 35% H2O2 solution is metered into the reactor with the inner tube at a flow rate of 100 microliters/minute. Boiling water is added between the inner tube and the outer tube. Upon exiting the reactor, the mixture of hydrogen peroxide and hot water generates high temperature gas bubbles. After two hours, a bituminous extract weighing several kg is collected and dried in powder form. The rest of the material consists of sand and pebbles that have been cleaned of their bitumen.

[0188] FIG. 10 shows a schematic representation of a third embodiment of a device for carrying out the method, in which the bitumen is skimmed off at the liquid surface.

At high temperatures (typically above 35°C) the bitumen floats on the water after separation and can be separated by skimming. At low temperatures, the bitumen basically falls out and sinks to the bottom of the reactor. Below 35 °C the bitumen has a density of about 1.03 t/m3. In order to achieve a sufficiently efficient separation of the bitumen over the liquid surface, the density of the liquid should be 1,045 t/m 3 , for example. In order to ensure that the bitumen floats on the surface of the water even at low temperatures, the density of the water can be increased to or above this value using additives such as salt, sugar, suspended matter, sludge, etc. This can be achieved, for example, by adding at least 5% Na2CO3. At the same time, since the sand and gravel have a higher density, the bitumen can be effectively separated from the sand and gravel at low temperatures and simply skimmed off the water surface.

FIG. 10 shows a device 500 with which this method can be carried out. The milled material is fed into the reactor 510 by a conveyor belt 520 . In the reactor 510 there is an aqueous solution with 5% Na2CO3. The process temperature here is 20 °C. This means that the bitumen in the milled material has a lower density than the liquid and therefore floats on the liquid after it has been separated from the sand/gravel. As described above, the process can be supported by flotation. Depending on the intensity of the flotation, there is no need to increase the density. The sand and filler which settles on the bottom of the reactor is discharged from the reactor 510 via a line 530 .

FIG. 11 shows a schematic representation of a fourth embodiment of a device for carrying out the method, the bitumen being collected and discharged at the bottom of the container.

If the reaction is carried out in cold water (below 35°C), there is also no need to increase the density of the liquid. In this case, the bitumen can sink to the bottom of the reactor 610 together with the minerals (sand, gravel). The sand and gravel can be removed with a 620 mineral specific auger. The filler can be flushed out via a line 630 with the reagent foam. The bituminous residue can be discharged from the reactor 610 at the end of the separation process or by a special mechanical means (e.g. chain scraper).

In a further variant, the separated bitumen is kept in suspension, for example by adjusting the density or by a suitable stirring process. During the process, the liquid with the suspended bitumen is pumped out and separated from the liquid in a separate container, for example by decanting. The separated liquid can be returned to the reactor. This allows the bitumen to be removed from the liquid in a continuous process. Sand/gravel and the filler can also be continuously removed from the liquid, for example via a mineral-specific screw conveyor. The entire process can thus be carried out continuously.

In an after-treatment, the materials (sand, gravel, bitumen, etc.) can be rinsed in order to free them from residues of the additives (e.g. common salt, iron chloride, peroxide, etc.). The bitumen can be dewatered, in particular, for example, pressed, compacted, heated.

In summary, it can be stated that, according to the invention, a method for separating bituminous material from a secondary raw material is created, which can be carried out particularly effectively and with little effort.

Claims (49)

1. A method for separating bituminous material from a matrix of a bituminous secondary raw material, comprising the following steps: - Mixing the bituminous secondary raw material with a liquid to form a mixture; - separating at least part of the bituminous material from the matrix. 2. The method according to claim 1, characterized in that the bituminous material is collected on a liquid surface of the mixture. 3. The method according to claim 1 or 2, characterized in that the bituminous secondary raw material comprises bituminous road surfacing material, a bituminous road surfacing concentrate produced from bituminous road surfacing material, in particular by a mechanical concentration process, particularly preferably produced by an abrasion process, and/or bituminous roofing felt. 4. The method according to any one of claims 1 to 3, characterized in that a density difference between the floating on the surface bituminous material and the mixture is increased by adding at least one first substance affecting the density. 5. The method according to any one of claims 1 to 4, characterized in that the liquid is water. 6. The method according to claim 5, characterized in that the first substance influencing the density is a water-soluble first substance, in particular an alkali or an acid such as sodium hydroxide (NaOH) or a salt, preferably common salt, magnesium chloride, calcium chloride, potassium chloride, sodium bicarbonate, sodium nitrate, particulate matter, filler or a mixture thereof, or a water soluble liquid, in particular a water soluble polyol such as glycerol, which is added directly or indirectly to the mixture. 7. The method according to any one of claims 4 to 6, characterized in that the first substance affecting the density comprises a non-polar first substance which has a lower density than the bituminous material, the non-polar first substance being added to the bituminous material. 8. The method according to any one of claims 1 to 7, characterized in that a chemical and / or physical reaction is generated in the mixture by adding at least one second substance in the mixture. 9. The method according to claim 8, characterized in that the second substance comprises sodium bicarbonate and/or acetic acid. 10. The method according to claim 8 or 9, characterized in that the second substance is a separating agent, in particular a peroxide, preferably hydrogen peroxide, oxygen, hydroxide radicals, perhydroxyl, peroxide, carbonates, percarbonates, permanganates, iron sulfate, iron(II) salts, iron (III) salts or a combination of the above. 11. The method according to any one of claims 8 to 10, characterized in that the second substance comprises surfactants and / or ambiphiles. 12. The method according to any one of claims 8 to 11, characterized in that the second substance is generated with an electrochemical and / or chemical system. 13. The method according to any one of claims 8 to 12, characterized in that the second substance is added continuously or in several portions during the separation of at least part of the bituminous material from the matrix. 14. The method according to claim 13, characterized in that during the separation of at least part of the bituminous material from the matrix, a concentration of the second substance, based on a total weight of the mixture, of at most 0.05% by weight to at most 1.0% by weight, preferably at most 0.01% by weight is increased to 0.5% by weight. 15. The method according to claim 13 or 14, characterized in that a change in concentration of the second substance, based on the total weight of the mixture, is between 10 -2 and 10 -5% by weight per minute, preferably between 10 -3 and 10<-4>% by weight per minute. 16. The method according to any one of claims 2 to 15, characterized in that gas bubbles are released in the mixture, so that the bituminous material at least partially adheres to gas bubbles and floats to the surface of the mixture. 17. The method according to claim 16 and one of claims 8 to 15, characterized in that the gas bubbles are generated by the second substance, in particular by a chemical reaction. 18. The method according to claim 17, characterized in that the gas bubbles are generated by a chemical reaction, wherein the second substance comprises a peroxide, a bicarbonate, a percarbonate or a combination of the above, wherein the chemical reaction to form the gas bubbles by heat and /or is accelerated by adding a homogeneous catalyst, preferably iron chloride, iron oxide, ozone, Javel water, potassium iodide or a mixture thereof and/or with a heterogeneous catalyst such as silver wire or ceramics. 19. The method according to claim 17, characterized in that the second substance is metered into the mixture via a first outlet opening below level and wherein a local area around the first outlet opening is heated and/or the catalyst is metered into the local area around the first outlet opening. 20. The method according to claim 19, characterized in that the local area of the first outlet opening is heated with steam and/or hot water. 21. The method according to claim 20, characterized in that the second substance is metered in via a first tube having the first outlet opening, and wherein the steam and/or the hot water or, alternatively or additionally, the catalyst is metered in via a second tube . 22. The method according to claim 21, characterized in that the first tube and the second tube are guided coaxially. 23. The method according to claim 16, characterized in that the gas bubbles are generated with a pump and/or in a separate, second container, in particular in a pressure container. 24. The method according to claim 23, characterized in that a catalyst is placed in an aqueous solution in the second container, and a peroxide, a bicarbonate, a percarbonate or a combination of the above are metered into the second container via a first feed line and wherein a connecting line is used to conduct a gas formed in the second container into the first container below the level. 25. The method according to claim 24, characterized in that the gas bubbles comprise ambient air, oxygen, nitrogen and/or carbon dioxide. 26. The method according to any one of claims 1 to 25, characterized in that an average temperature of the liquid during the method is below 60 °C, preferably below 40 °C, particularly preferably below 30 °C, particularly preferably at room temperature. 27. The method according to any one of claims 1 to 26, characterized in that the mixture is mixed mechanically, in particular to maximize the yield. 28. The method according to claim 27, characterized in that the mixture is acted upon by physical means, in particular by sound, ultrasound and/or microwaves. 29. The method according to any one of claims 1 to 28, characterized in that it is carried out discontinuously. 30. The method according to any one of claims 1 to 29, characterized in that after the separation of the bituminous material, the liquid, in particular the water, is processed for reuse in the process, in particular for a next batch. 31. The method according to claim 30, characterized in that a process heat is recovered with one or more heat exchangers. 32. The method according to claim 2, characterized in that the bituminous material on the liquid surface, in particular in the form of a foam, is skimmed off or sucked off continuously or discontinuously. 33. The method according to any one of claims 1 to 32, characterized in that the bituminous material is subjected to a further purification step after separation from the matrix. 34. The method according to claim 33, characterized in that the bituminous material is separated from foreign bodies, in particular from filler and sand, after separation from the matrix by centrifugation. 35. The method according to any one of claims 1 to 34, characterized in that the secondary raw material runs through the process several times to achieve a greater separation efficiency. 36. The method according to any one of claims 1 to 35, characterized in that the method is carried out at reduced pressure. 37. The method according to any one of claims 1 to 36, characterized in that the secondary raw material comprises chippings, sand and filler. 38. The method according to any one of claims 1 to 37, characterized in that the secondary raw material has a water content of less than 5 wt. %, preferably less than 1 wt. %, particularly preferably less than 0.1 wt. % includes. 39. The method according to any one of claims 1 to 38, characterized in that the secondary raw material is present as fragments, with at least a proportion of 10% by weight, preferably at least 20% by weight. % of the fragments have a minimum diameter of more than 10 mm. 40. The method according to any one of claims 1 to 39, characterized in that at least 20% by weight, preferably at least 30% by weight, particularly preferably at least 40% by weight, of the matrix has a particle size of more than 5 mm. 41. The method according to any one of claims 1 to 40, characterized in that the secondary raw material comprises one or more of the following components: polymers, reinforcing fibers, in particular cellulose fibers and/or aramid fibers, hydrated lime, juvenators. 42. The method according to claim 41, characterized in that the proportion of hydrated lime is between 0.5 and 3% by weight, preferably between 1 and 2% by weight. 43. The method according to claim 41 or 42, characterized in that the proportion of polymers in the bituminous material is at least 2% by weight, preferably at least 4% by weight. %, in particular between 5 and 7% by weight. 44. The method according to any one of claims 1 to 43, characterized in that the secondary raw material has a density between 1.2 g/cm 3 and 2.6 g/cm 3 , preferably between 1.4 g/cm 3 and 2.4 g/cm <3>has. 45. The method according to any one of claims 1 to 44, characterized in that a proportion of VOC or VVOC in the secondary raw material is less than 0.1 wt. %, preferably less than 0.01 wt. % and/or a proportion of distillable petroleum components in the secondary raw material is less than 0.1 wt. %, preferably less than 0.01 wt. % is. 46. The method according to any one of claims 1 to 45, characterized in that a kinematic viscosity of the bituminous material is higher than 400 mm 2 /s, preferably higher than 1000 mm 2 /s. 47. The method according to any one of claims 1 to 46, characterized in that a density of the bituminous material is greater than 1000 kg/m 3 , preferably greater than 1010 kg/m 3 . 48. Use of bituminous material, which has been separated from a secondary raw material by a method according to any one of claims 1 to 47, for the production of asphalt. 49. Device for carrying out a method according to any one of claims 1 to 48.