METHOD FOR SEPARATION OF POLYISOPRENE AND OTHER APOLAR RAW MATERIALS FROM PLANT RAW MATERIALS

Description

[0001] The present invention relates to a method for separating polyisoprene and other nonpolar valuable substances from plant raw materials according to the preamble of claim 1.

[0002] Natural rubber consists primarily of a polymer made up of isoprene units, specifically cis-1,4-polyisoprene. Today, natural rubber is mainly extracted from the latex of the rubber tree, a process that is very labor-intensive and involves long transport routes to the processor. Furthermore, prices fluctuate considerably depending on the weather and the availability of the raw material in the producing countries.

[0003] German patent application DE 10 2007 047 764 A1 discloses a process for removing unwanted substances from plant proteins. The extraction is carried out using an extraction solvent, yielding a plant protein extract. After adding an inorganic adsorbent material to the plant protein extract, the unwanted substances bind to the inorganic adsorbent material.

[0004] German patent application DE 10 2013 107 279 A1 discloses a process for extracting natural rubber, and thus polyisoprene, from dandelion root material as a plant-based raw material. Following a biological decomposition process as an initial pretreatment, the root material is subjected to a mechanical comminution process, in which the root material is crushed and the natural rubber is released. During this process, the natural rubber particles are said to agglomerate. The biomass in solution can then be separated and isolated from the natural rubber agglomerates. It is only mentioned in passing that the mechanical comminution process can be carried out using a rotary grinding mill, without any further details being provided on how such a mill should be designed.

[0005] Plants with a lower rubber content or with low-molecular-weight rubber are not currently used for polyisoprene production due to the low efficiency or problematic state of the viscous isoprene product. These plants are sometimes cultivated in different growing regions than rubber trees, so broadening the plant base for raw material extraction would reduce the harvest risk for rubber demand. Furthermore, some rubber-containing plants are already cultivated for other value chains, but the rubber-containing biomass is currently generated as waste because of a lack of technical processes to make natural rubber economically viable. This results in the loss of a significant amount of biomass that could be used for polyisoprene production with a suitable manufacturing process.In the development of natural rubber / polyisoprene from plant-based raw materials, it has so far been overlooked that the separation of other non-polar valuable substances from plants is also possible within the framework of a process for processing plant-based raw materials.

[0006] Accordingly, the object of the present invention is to provide a method by which it is possible to obtain polyisoprene from plants with a lower rubber content or with low molecular weight rubber in a technically simpler way.

[0007] The problem is solved for a generic process by adding an adsorbent material to the grinding mixture before or during mechanical processing in the wet phase.

[0008] The first pretreatment of the plant raw materials can consist of cooking, washing, crushing and / or chemical and / or biological decomposition of the plants, which prepares the cells of the plant raw materials for subsequent breakdown by beating, cutting and / or rubbing mechanical processing in the wet phase.

[0009] During the impact, cutting, and / or abrasive mechanical processing of plant-based raw materials in a wet phase, natural rubber is extracted from the surrounding biomass and floats in the liquid phase. Hereafter, we will only refer to natural rubber, specifically the polyisoprene that is to be separated from the remaining biomass of the plant-based raw materials. In this state, the natural rubber tends to agglomerate. However, the agglomeration process takes time, during which the ground material mixture must be held in the containers used for mechanical processing. This increases the volume and cost of the equipment required for processing the plant-based raw materials. Furthermore, it is difficult to determine the optimal time to end the mechanical processing.It is possible that not all of the natural rubber has yet detached from the adhering biomass and floated to the surface of the mechanically processed regrind mixture, agglomerating with other natural rubber. In this case, stopping the mechanical processing at this point would lead to a lower yield of natural rubber. On the other hand, stopping the mechanical processing could also be delayed too long, because continued mechanical processing could separate and break down already agglomerated natural rubber, making it impossible to separate it from the wet phase in the subsequent separation process without an unreasonable amount of effort.In the known processes, the processes overlap uncontrollably, meaning that on the one hand not all natural rubber has yet separated from the surrounding biomass, and on the other hand, already agglomerated natural rubber is destroyed again by the continued processing.

[0010] This analysis makes it clear that it is advantageous to accelerate and support the detachment of natural rubber from the surrounding biomass and the agglomeration of the natural rubber during mechanical processing in the wet phase. By accelerating and supporting detachment and agglomeration, the residence time of the ground material mixture in the wet-phase mechanical processing plant is reduced. This allows the plant to be designed smaller and therefore more cost-effectively while maintaining the same throughput. At the same time, the yield of natural rubber from the processed plant raw materials also increases because the overlap between the extraction of natural rubber from the biomass and the ongoing destruction of the already formed agglomerates is reduced or even completely avoided.This allows the optimal time to be determined more precisely for ending the mechanical processing of the plant raw materials in the wet phase, which also increases process efficiency.

[0011] The plant raw material from which the natural rubber should be obtained can be from the group of plant families Apocynaceae, Asteraceae, Euphorbiaceae, Moraceae or crosses with latex plants from the group of Agoseris glauca, Apocynum venetum, Chrysothamnus graveolens, Chrysothamnus nauseosus, Chrysothamnus viscidiflorus, Funtumia elastica, Parthenium argentatum, Scorzonera acanthoclada, Scorzonera albicaulis, Scorzonera divaricate, Scorzonera hissaricata, Scorzonera racemosa, Scorzonera tau-saghyz, Scorzonera tragapogonoides, Scorzonera turkestania, Scorzonera virgate, Solidago canadensis scabra, Solidago fistulosa, Solidago leavenworthii, Solidago rigida, Sonchus oleraceus, Taraxacum brevicorniculatum, Taraxacum hybernum, Taraxacum koksaghyz, Taraxacum megalorrhizon, Taraxacum officinale, Cichorium intybus L., Musaceae especially with the genera Musa, Ensete and Musella or corresponding hybrids may be chosen.Rubber obtained from these plant families, or mechanically processed parts of these plants that are prepared in such a way that polyisoprene can bind to the polyisoprene contained in these plants, can also be used as adsorbent material.

[0012] Nonpolar synthetic rubbers such as Acrylic Rubber (ACM), Butadiene Rubber (BR), Butyl Rubber (IIR), Chlorosulfonated Polyethylene (CSM) / Hypalon, Ethylene Propylene Diene Monomer (EPDM), Fluoroelastomers (FKM) / Viton, Isoprene Rubber (IR), Nitrile Rubber (NBR), Perfluoroelastomer (FFKM), Polychloroprene (CR) / Neoprene, Polysulfide Rubber (PSR), Silicone Rubber (SiR), Styrene Butadiene Rubber (SBR) can also be used as adsorbent material. Furthermore, vegetable / animal oils and fats (e.g., safflower oil, peanut oil, hemp oil, herring oil, pumpkin seed oil, almond oil, corn oil, poppy seed oil, lard, beef tallow, castor oil, sesame oil, soybean oil, sunflower oil, grapeseed oil, walnut oil, wheat germ oil, olive oil, rapeseed oil, palm oil, coconut oil, linseed oil, coconut fat) or mineral oils (e.g., white oils) can be used. Examples of technical adsorbers are Ultra-X-Tex, UltraSorb, and QuickSorb.

[0013] The detachment of natural rubber from the surrounding biomass and its agglomeration during wet-phase mechanical processing is accelerated and supported by adding an adsorbent material to the milled material mixture during this process. During adsorption, the natural rubber molecules adhere to the surface of the adsorbent material and accumulate there. However, the natural rubber, as the adsorbate, does not form a chemical bond with the surface of the adsorbent material, but rather adheres through weaker forces similar to adhesion. The forces causing this adhesion are not chemical bonds, but rather van der Waals forces. This form of adsorption is more precisely called physical adsorption or physisorption. Unlike chemisorption, no chemical reaction occurs between the natural rubber and the adsorbent material.The adsorption energy for physisorption ranges from 4 to 40 kJ / mol. Chemical bonds within an adsorbed particle remain intact, but become polarized.

[0014] The adsorbent material with the adsorbed natural rubber can be used as composite isoprene. It is also possible to separate low-molecular-weight isoprene and other lipids using conventional methods. These conventional separation methods can be based on thermal, mechanical, or chemical principles.

[0015] Adsorption is reversible, as the particles can leave the surface again using a similar amount of energy to that released during adhesion. These reactions are generally not inhibited by transition states. The activation energy of the reaction is therefore equal to the adsorption energy. Adsorbed particles do not have a fixed binding site on the surface; they do not remain at the location where they were adsorbed but move freely along the surface. The position of the equilibrium depends on the properties and size of the surface, the properties and pressure or concentration of the adsorbate, and the temperature.

[0016] By adding the adsorbent material to the milled material mixture during mechanical processing in the wet phase, polyisoprene and other valuable lipids can be extracted and separated from the plant-based raw materials with high efficiency. In the wet phase, the natural rubber extracted from the surrounding biomass can more easily migrate to and adhere to the adsorbent material. Thus, the use of the wet phase significantly enhances adsorption. No organic solvents are used in the adsorption process. The resulting product is a plant-based wet sludge, which can be used as an animal feed additive, biogas substrate, fertilizer, or for the purification of polar substances such as carbohydrates like inulin. The natural rubber extracted from the plant-based raw materials and enriched with the adsorbent material can be further processed using established rubber refining methods.For example, the processing of Taraxacum kok-saghyz is extensively described in patent literature. These processing methods can also be used to process the natural rubber adsorbed from the plant raw materials together with the respective adsorbent material used.

[0017] When this description refers to a mixture of materials to be ground, it means the plant-based raw material in its liquid phase, which is subjected to mechanical processing. Although the term "mixture of materials" is used for the sake of simplicity, this does not mean that the mechanical processing is limited to purely grinding processes. Alternative or additional mechanical processing methods include, for example, cutting, crushing, or impact. Accordingly, the term "grinding media mill" used in this description is not technically limited to a mill that exclusively uses grinding media.Devices for the mechanical processing of the grinding mixture in the liquid phase also include roller mills, planetary mills, impact mills, cutting mills, planetary roller extruders, twin screw extruders or choppers, cutters or shredders, alone or in any combination with each other, which are referred to in this description for simplicity as grinding media mills as a collective term.

[0018] According to one embodiment of the invention, in addition to the adsorption of polyisoprene, other valuable nonpolar substances from plant raw materials, in particular lipids such as triterpenoids, polyphenols, flavonoids, and unsaturated fatty acids, can also be adsorbed as an alternative to the previous extraction methods using organic solvents or other, less environmentally friendly processes. These substances are suitable for use in the pharmaceutical industry. The addition of the adsorbent material thus makes it possible to separate further valuable components of plant raw materials from the milled material mixture during the wet-phase mechanical processing stage, in addition to the natural rubber. Due to the simple adhesion, the nonpolar substances can also be separated from the adsorbent material and the natural rubber later, after mechanical processing, with comparatively little effort and made available separately.

[0019] According to one embodiment of the invention, the mechanical processing takes place in a continuous-flow grinding mill. Unlike batch processing, a continuous-flow grinding mill offers higher throughput, reduced personnel costs, and better adaptability of process parameters to changing requirements. A continuous-flow grinding mill operates much more efficiently because the downtime required for loading and unloading the equipment is eliminated. The adsorbent material can be easily fed into the grinding chamber of a continuous-flow grinding mill. The amount of adsorbent material fed can also be easily adjusted to the specific requirements.

[0020] According to one embodiment of the invention, the surface of the adsorbent material on which adsorption takes place is the surface of a solid or the surface of a liquid, and the adsorbent material is a nonpolar adsorbent. A solid or liquid can be easily fed into the grinding mixture. The adsorbent material can be added to the grinding mixture before it is conveyed into the grinding chamber of the grinding media mill, or it can be added to the grinding mixture during mechanical processing in the grinding chamber. The nonpolar adsorbent can be substances such as natural rubber, synthetic rubber, vegetable or animal oils and fats, mineral oils, or technical adsorbents such as activated carbon, graphite, or polymer adsorbents.

[0021] According to one embodiment of the invention, the solid and / or liquid adsorbent material is continuously fed into the grinding chamber of the grinding media mill. This continuous addition to the grinding chamber ensures that, despite the continuous flow of a material mixture, no dilution effect occurs in the concentration of the adsorbent material within the mixture due to the constant inflow and outflow of the material mixture. The proportion of adsorbent material in the material mixture can be kept at least approximately constant within the grinding chamber, thus ensuring a consistently high yield of natural rubber.

[0022] According to one embodiment of the invention, the natural rubber and / or the adsorbent material is separated from the wet phase by mechanical separation processes. Examples of suitable mechanical separation processes include sieving, filtration, flotation, and / or air classification. These mechanical separation processes are cost-effective and reliable.

[0023] According to one embodiment of the invention, the mechanical processing of the material mixture during the wet phase takes place in a grinding media mill. In this specific embodiment of the invention, the term "grinding media mill" is limited to precisely this type of mill. The grinding media mill can preferably be operated continuously by continuously feeding a material mixture into the drum of the mill via the feed device. The material mixture then passes through the grinding chamber along the axis of rotation and is finally conveyed out of the drum by the discharge device. The material mixture contains at least some liquid, which facilitates the conveyance of the plant-based raw materials through the drum and their more even distribution within it. The liquid is also necessary to allow the natural rubber to agglomerate into flakes after it has separated from the rest of the biomass.

[0024] The continuous rotation of the drum causes the grinding media in the respective compartments to move against each other and, following the direction of rotation, to be continuously advanced. As the grinding media shear past and rub against the plant material located between them, the material is broken down. When the process parameters are switched from cascade to cataract mode, the grinding media also fall from above onto the mixture of materials being ground. The impact force acting on the plant material further breaks it down. The number of grinding media and the rotational speed of the drum result in a corresponding number of impacts within a given time interval, impacting the plant material in the compartments and disrupting its cell structure.During this process, the natural rubber contained in the plant-based raw materials is released and can float to the surface in the liquid that forms part of the ground material mixture, agglomerating into flakes. As agglomerated flakes, the natural rubber can then be easily separated from the other components of the ground material mixture.

[0025] If the grinding chamber in the drum of the grinding media mill is divided into several compartments, successive zones are created in the direction of flow of the material mixture through the drum, in which the plant-based raw materials can be processed with varying degrees of intensity. For example, it is possible to provide intensive processing for initial extraction in the first compartment, perhaps by loading it with appropriate grinding media, while processing in the subsequent compartments can be gentler to separate the natural rubber from the other plant components and promote agglomeration. The drum as a whole has a length and a number of compartments necessary to extract the plant-based raw materials sufficiently for the natural rubber to agglomerate.The compartments can be designed with varying lengths to influence the residence time of the plant materials within each compartment. For example, a short compartment, where the plant materials are subjected to more intensive grinding with heavy grinding media, can be followed by a longer compartment with few or no grinding media, where the plant materials are essentially only moved and rinsed in the liquid of the grinding mixture. The partitions can also be mounted so that they are movable along the axis of rotation within the drum, allowing for adjustments to the length of the compartments.

[0026] If the partition walls have openings through which the material mixture can pass from one compartment to an adjacent one, the material mixture flows automatically through the drum. In particular, feeding the material mixture to one side of the drum creates a flow within the grinding chamber, causing the mixture to flow from an upstream compartment to the next downstream compartment until it reaches the discharge device for removing the processed material mixture. The openings are preferably dimensioned to retain the grinding media in a compartment while allowing the material mixture to flow through them. However, one or more openings can also be designed to allow grinding media to pass through.However, if such passage openings are positioned further inwards towards the axis of rotation, at a distance from the outer wall of the compartments, the number of grinding media that actually pass through such a passage opening into the adjacent compartment remains low, especially if there are relatively few grinding media in that compartment. The passage openings can be adjustable in size to adapt them to different plant-based raw materials and their material properties, or restrictors can be attached to the passage openings, resulting in different sized or shaped openings. Passage openings can also be designed as a type of sieve to qualitatively separate larger components of the plant-based raw materials or contaminants from the grinding mixture.The shape, position, and size of the openings also influence the flow rate and speed of the grinding mixture through the drum. They are dimensioned, designed, and positioned to achieve a suitable flow rate for processing the plant-based raw materials, ensuring that the natural rubber, agglomerated into flakes, arrives in the final compartment of the drum or forms there and can then be conveyed out of the drum.

[0027] The motor may also be equipped with a device that allows the drum speed to be adjusted. A faster drum rotation results in more impacts from the grinding media on the plant material within a given time interval; a lower rotation speed reduces the number of impacts per interval. The impacts exerted by the grinding media on the plant material in the grinding mixture also vary in intensity depending on the drum speed. Therefore, by changing the drum speed, the processing intensity of the plant material can be precisely controlled. If it turns out that the natural rubber agglomerates too early during the processing of a grinding mixture, the drum speed can be reduced to extend the agglomeration period. Conversely, the drum speed can be increased if the natural rubber agglomerates too late.The speed-changing device can influence the power available to the motor in order to change the speed of the motor that drives the drum, or the motor speed ratio is changed via a gearbox located between the motor and the drum.

[0028] In summary, the grinding media mill makes it possible to control the pulping of plant-based raw materials in the drum for the extraction of natural rubber. This is achieved by appropriately designing and adjusting the variable components of the mill described above, resulting in agglomerated natural rubber being found in the final section of the drum. The pulping process can be adjusted gently enough to avoid damaging the natural rubber during processing, yet aggressively enough to extract the natural rubber from the other plant components sufficiently for it to agglomerate within the milled material mixture. In the event of variations in the plant-based raw materials, the grinding media mill can also be adapted by changing the adjustable process parameters, ensuring that the natural rubber can be extracted from the drum in agglomerated form even with altered plant-based raw materials.Additionally, the agglomeration of the natural rubber is accelerated and supported by the addition of the adsorbent material to the ground material mixture.

[0029] Further features of the invention will become apparent from the claims, the figures, and the present description. All features and combinations of features mentioned above in the description, as well as those subsequently mentioned in the figure description and / or shown in the figures alone, are usable not only in the combinations specified, but also in other combinations or individually.

[0030] Based on a preferred embodiment and with reference to the accompanying drawings, it is explained in more detail below how natural rubber is extracted from a plant-based raw material during mechanical processing in the wet phase.

[0031] They show: Fig. 1: a side view of a grinding media mill, Fig. 2: a sectional view through the Fig. 1 Figure 3 shows a drum, Figure 4 an enlarged sectional view through a feeding device, Figure 5 a view of a drum with an ascending axis of rotation, Figure 6 a view of an intermediate wall, Figure 7 an infeed side view of the grinding media mill, Figure 8 a cross-sectional view through a drum with a receiving chamber, and Figure 9 a process flow diagram.

[0032] In Fig. 1 Figure 2 shows a side view of a grinding media mill 2. The grinding media mill 2 has a drum 4 through which a mixture of materials is conveyed in order to extract the natural rubber contained in a plant-based raw material and to agglomerate the natural rubber so that it can be easily removed and separated from the mixture of materials as an agglomerate.

[0033] The drum 4 is rotatably mounted about a pivot axis 6. The pivot axis 6 can be a true shaft, or it can be defined solely by the way the drum 4 is mounted. The drum 4 is set into rotation by the two motors 8 shown in the exemplary embodiment. Inside the drum 4 is a grinding chamber 10 in which the material mixture is processed by grinding media located within the grinding chamber 10. The grinding media are not shown in the figures.

[0034] The drum 4 has a first end face 12 from which the material mixture is fed into the grinding chamber 10. After passing through, the material mixture leaves the grinding chamber 10 again via the discharge device 18, which is located in the area of ​​the second end face 14. The material mixture is fed into the grinding chamber 10 via a separate feed device 16 and a rotary feedthrough 20. A rotary feedthrough may also be provided in the area of ​​the discharge device 18.

[0035] To enable the insertion and removal of grinding media into the grinding chamber 10, a number of openings 22 are provided in the wall of the drum 4. The openings 22 can be assigned to a respective compartment within the grinding chamber 10.

[0036] In the exemplary embodiment, the drum 4 is composed of six pipe segments 24. Each pipe segment 24 has end-face flange surfaces 26 that are congruent with the flange surfaces 26 of other pipe segments 24. By simply stacking the flange surfaces 26 on top of each other, any number of pipe segments 24 can be assembled into a drum 4 in any orientation. The pipe segments 24 can have different lengths along the axis of rotation 6 and different diameters. The diameters of the pipe segments 24 can also vary along their length in the direction of the axis of rotation 6.

[0037] In the exemplary embodiment, the drum 4 is supported on rollers 28 at its outer circumference. The two in Fig. 1 The rollers 28 shown are driven by the motors 8. In the exemplary embodiment, the rollers 28 run on the outer edges of the flange surfaces 26, so that these form a circumferential track.

[0038] The grinding material mixture can be fed to the grinding chamber 10 via the feed hopper 30. For this purpose, the grinding material mixture is filled into the feed hopper 30 from above. From there, it is fed to the grinding chamber 10 via the rotary feedthrough 20. In the exemplary embodiment, the feed hopper 30 has an additional feed line 32 through which liquids or gases can be added to the grinding material mixture. By arranging the feed line on the feed side of the drum 4, it is possible to further liquefy or loosen the grinding material mixture, or—if the medium conveyed through the feed lines 32 is introduced into the feeding device 16 under high pressure or at a high temperature—to further break down the biological raw materials. For example, the feed lines 32 can supply a liquid via a steam nozzle or a spray valve that breaks down the cell structures of the plant raw materials through mechanical action and / or thermal action.

[0039] The dispensing device 18 can be provided with an end wall 34 that limits the dispensing device 18.

[0040] The work processes performed with the grinding media mill 2 can be set and controlled via a control unit 36. The control unit 36 ​​is connected to the devices 38, which allow the rotational speed of the drum 4 to be variably adjusted. The device 38 can be a power control for the motor 8. However, other configurations for the device 38 are also possible, such as a planetary or variator gear, with which the rotational speed of the drum 4 can be variably adjusted.

[0041] The controller 36 is connected to the device 38 (an example of a speed control), the actuator 44 (an on / off switch or speed controller for the feed device 16), and a camera 42 (an example of a sensor) via corresponding connecting lines 40. The connecting lines 40 can be wired cables, but other connection types are also possible, such as a wireless connection via radio, fiber optics, or other media for data transmission.

[0042] In the Fig. 1 In the illustrated embodiment, the drum 4 is supported by a total of four rollers 28, of which the two rollers 28 shown in the foreground are each driven by a motor 8. Depending on the length and weight of the drum 4, additional rollers 28 may also be provided. It is also possible to drive more or just a single roller 28.

[0043] In Fig. 2 is a cross-sectional view through the in Fig. 1 The drum 4 is shown. In the sectional view, a total of 6 partitions 46 are visible, which divide the grinding chamber 10 into seven compartments 48. Grinding media can be arranged in each of the compartments 48, whereby the number, weight, shape, and size of the grinding media can vary between the individual compartments 48. The selection of the grinding media to be placed in each compartment 48 influences the breakdown of the biological raw materials, the separation of the natural rubber from the biological raw materials, and the agglomeration of this natural rubber.

[0044] In the Fig. 2 The sectional view shown reveals that the inner surfaces 50 of the outer walls 52 are not parallel to the axis of rotation 6, but rather have a conical shape. The flow rate of the grinding mixture through the compartments 48 and the grinding chamber 10 as a whole can be influenced by the angle of inclination of the outer walls 52 and the inner surfaces 50 to the axis of rotation 6. While the inner surface 50 of the wall of the first tube segment 24 has an angle of inclination of 85 degrees to the axis of rotation 6, the inner surface 50 of the second tube segment 24 is angled at 79.5 degrees. Of course, other angles of inclination can also be selected. Other non-cylindrical shapes for the tube segments 24 are also possible.

[0045] The pipe segments 24 are of a suitable length to allow for the appropriate processing of the plant raw materials in the associated compartment 48. The number, length, diameter, and shape of the pipe segments assembled to form a drum 4 can be appropriately designed and selected by a person skilled in the art.

[0046] The flange surfaces 26 of the pipe segments 24 can be connected to each other via connecting elements, such as a number of screws with locknuts or bolts.

[0047] In the section view in Fig. 2 It is clearly visible that the grinding chamber 10 has a conically tapered constriction towards the discharge device 18 in the area of ​​the second end face 14, and thus at its downstream end. The constriction shown is well suited to skimming off flakes of agglomerated natural rubber floating on the surface of the grinding material mixture. Discharge can be achieved either by increasing the feed rate of the grinding material mixture into the grinding chamber 10, thereby generating a flow impulse within the grinding chamber 10, and / or by raising the rotary axis 6 of the drum 4 at the feed end and / or lowering it at the discharge end, thereby flushing the flakes out of the grinding chamber 10 without washing away increased amounts of the other plant-based raw materials.The fraction of the ground material mixture that no longer contains a significant amount of natural rubber can then be discharged from the last compartment 48, whereby the respective fractions can be separated by the discharge device 18 by conveying them into different discharge containers. It is also possible, of course, to discharge the entire ground material mixture from the grinding chamber 10 without separately skimming off the agglomerated natural rubber with the grinding media mill 2.

[0048] The Fig. 3 Figure 16 shows an enlarged sectional view of the feeding device 16. For feeding the material mixture to be ground, the feeding device 16 has a connection port 54 to which the feed hopper 30 can be connected. The feed line 32 is also located in the area of ​​the connection port 54. The feeding device 16 incorporates a screw conveyor 56, which serves as a driven positive feeder. This screw conveyor extends through the rotary feedthrough 20 and conveys the material mixture fed via the connection port 54 into the grinding chamber 10. The screw conveyor's blades reliably push the plant-based raw materials into the grinding chamber 10. At the same time, they prevent grinding media, which are moved within the grinding chamber 10 during the rotation of the drum 4, from entering the feeding device 16. The positive feeder 56 also prevents backflow of the material mixture into the feeding device 16. The forced feed 56 is arranged coaxially to the axis of rotation 6 of the drum 4.

[0049] In Fig. 4 A grinding media mill 2 is shown in which the axis of rotation 6 of the drum 4 is raised relative to the horizontal W. Since this also causes the inner surfaces 50 of the tube segments 24 to rise to the right along the axis of rotation 6 relative to the horizontal W in the conveying direction, the conveying speed at which the material mixture passes through the grinding chamber 10 is naturally reduced in such an angular position of the drum 4. Conversely, it is conceivable that if the axis of rotation 6 is angularly positioned so that it slopes downwards relative to the horizontal in the conveying direction, the conveying speed of the material mixture through the grinding chamber 10 is increased. In the exemplary embodiment, the drum 4 is held on a frame, which in turn is supported on the ground by rotary bearings.Mechanical positioning devices can be provided to change the spatial position of the axis of rotation 6, but it is also possible to raise or lower the frame by means of motorized actuators such as a lifting cylinder on one or both sides.

[0050] In Fig. 5 Figure 1 shows a front view of a partition wall 46. The partition wall 46 has a number of passage openings 58 through which the grinding mixture can flow from one compartment 48 to the adjacent downstream compartment 48. In the Fig. 5 In the illustrated embodiment, the passage openings 58a, 58b and 58c have different shapes and sizes. While the passage openings 58a are dimensioned in shape and size to retain the grinding media located in one compartment, the passage openings 58b are dimensioned in shape and size to allow grinding media to pass through them into an adjacent compartment.

[0051] In the Fig. 5 In the depicted partition wall 46, the passage opening 58c is designed as a recess 60, the radius R1 of which is larger in at least part of the circular arc covered by the recess 60 than the outer circumference of the axis of rotation 6 determined by the radius R2 in the area of ​​the corresponding partition wall 46. In the Fig. 5 In the illustrated embodiment of an intermediate wall 45, the recess 60 is provided with a grid to prevent the passage of grinding media. If the in Fig. 5 However, if the grid shown is omitted in the exemplary embodiment, it is possible to move sensors 42 along the axis of rotation 6 through one or more compartments 48. Fig. 5 It can be seen that the camera, as sensor 42, is arranged adjacent to the axis of rotation 6 in the grinding chamber 10. When the grinding chamber 10 is filled with a grinding mixture 64, as indicated by the wavy line 62, the sensor 42 is positioned at a distance from the grinding mixture 64 such that damage to or contamination of the sensor 42 is unlikely.

[0052] In Fig. 6 A feed-side view of the grinding media mill 2 is shown. The round circumferential shape of the drum 4 is clearly visible in this view. The feeding device 16 with the funnel-shaped feed hopper 30, the connecting nozzle 54 located below it, and the several feed lines 32 are also visible. The pivot axis 6 is also visible in the end view, where the pivot axis 6 represents the rotary bearing of the forced feed 56, which is driven by a separate motor 8. This view also clearly shows that the drum 4 is held on the frame 66 by the rollers.

[0053] In Fig. 7 The figure shows a discharge-side view of the grinding media mill 2. In this view, the inspection windows 68 are visible, which are embedded in the end wall 34 in order to visually check whether the natural rubber contained in the biological raw materials has agglomerated into flakes in the last compartment 48 of the grinding chamber 10.

[0054] The grinding mixture 64, conveyed from the grinding chamber 10 via the discharge device 18, can be forwarded to downstream separation and cleaning devices via a discharge nozzle 70.

[0055] In Fig. 8 Figure 1 shows a cross-sectional view through a drum 4 with a receiving chamber 72. In the exemplary embodiment, the outer wall 52 of the drum 4 is designed as a perforated sheet, so that the grinding mixture 64 can pass from the grinding chamber 10 inside the drum 4 through the openings 74 in the perforated sheet to the outside into the receiving chamber 72. The openings 74 can be designed to allow grinding media from the grinding chamber 10 to pass through them into the receiving chamber 72, or they can be designed to prevent this. The receiving chamber 72 can be used to wash, cook, and / or separate and remove components of the grinding mixture 64 contained in it. Appropriate process tools can be arranged in the receiving chamber 72 for this purpose. In the exemplary embodiment, a screw conveyor 76 is shown, which can be used to remove sediment that accumulates at the bottom of the receiving chamber 72.Further heating elements 78 are shown, which can be used to heat the grinding mixture 64, for example to bring it to a boil.

[0056] Above drum 4 is in the Fig. 8 A further jacket 80, partially encompassing the circumference of the drum 4, is shown, on which nozzles 82 are arranged. A liquid, gas, or hot steam can be injected from the outside through the openings 74 in the outer wall 52 of the drum 4 into the grinding chamber 10 via the nozzles 82. The jacket 80 can also contain metering agents for adding solids to the grinding chamber, which are added to the grinding mixture to facilitate the detachment and separation of the polyisoprenes and other nonpolar materials released during processing.

[0057] The Fig. 9Figure 1 shows a process flow diagram. In the first pretreatment 100, the plant-based raw materials are prepared for the subsequent process step. Pretreatment 100 is followed by mechanical processing 102 of the plant-based raw materials. During this process, the plant-based raw materials are subjected to impact, cutting, and / or abrasive mechanical processing in a wet phase. Mechanical processing 102 can, for example, be carried out in a grinding mill 2, as described above. To improve the separation of the natural rubber from the remaining material mixture during process step 104, an adsorbent material 106 is added to the material mixture before or during mechanical processing 102.The adsorbent material 106 can be added to the plant-based raw material before or during pretreatment 100, added after pretreatment 100 but before mechanical processing 102, or added to the ground material mixture during mechanical processing. The natural rubber extracted from the plant-based raw material by mechanical processing 102 adheres to the adsorbent material 106 in the liquid phase of the ground material mixture. During separation 104, the adsorbent material 106, together with the adhering natural rubber from the plant-based raw material, can be separated as batch 108 from the remaining ground material mixture 110 for further processing.

[0058] The invention is not limited to the above embodiments.

Claims

1. Method for separating polyisoprene from vegetable raw materials, with a first pretreatment (100) of the vegetable raw materials, a mechanical processing (102) by striking, cutting and / or grinding of the vegetable raw materials following the pretreatment (100), in a wet phase, wherein the polyisoprene contained in the processed vegetable raw materials is extracted from the vegetable raw materials, and a separation (104) of the polyisoprene from the wet phase following the mechanical processing (102), characterized in that before or during the mechanical processing (102) in the wet phase, an adsorber material (106) is added to the grindstock mixture.

2. Method according to Claim 1, characterized in that in addition to the polyisoprene, other apolar value substances are also separated from the vegetable raw materials.

3. Method according to Claim 1 or 2, characterized in that the mechanical processing (102) takes place in a grinding-media mill (2) operated in continuous operation.

4. Method according to any of the preceding claims, characterized in that the surface of the adsorber material (106) on which the adsorption occurs is the surface of a solid or the surface of a liquid, and the adsorber material (106) is an apolar adsorber.

5. Method according to any of preceding Claims 3 and 4, characterized in that the solid and / or liquid adsorber material (106) is discharged continuously into the grinding chamber (10) of the grinding-media mill (2).

6. Method according to any of the preceding claims, characterized in that the separation (104) of the natural rubber and / or of the adsorber material (106) from the wet phase takes place by way of mechanical separation methods.

7. Method according to any of the preceding claims, characterized in that the mechanical processing (102) of the grindstock mixture takes place in the wet phase in a grinding-media mill (2).