WO2023275379A1

WO2023275379A1 - Method and plant for separating a magnetic, phosphorous-containing compound from a dry mass by means of dry magnetic separation

Info

Publication number: WO2023275379A1
Application number: PCT/EP2022/068324
Authority: WO
Inventors: Udo Comes; Karl Markgraf
Original assignee: Mutec Markgraf Gmbh
Priority date: 2021-07-02
Filing date: 2022-07-01
Publication date: 2023-01-05

Abstract

The invention relates to a method and to a plant for separating a magnetic, phosphorus-containing compound (4.3), in particular iron phosphate, from a dry mass (4.1), that is in particular composed of biogenic residues, by means of dry magnetic separation. The method comprises the following steps: a) providing the dry mass (4.1) in the form of a powder (4.2); and b) applying a magnetic field (25) to the powder (4.2) so that the magnetic, phosphorus-containing compound (4.3) is attracted by the magnetic field (25) and separated from the powder (4.2).

Description

Process and plant for separating a magnetic, phosphorus-containing compound from a dry mass by dry magnetic separation

The invention relates to a process for separating a magnetic, phosphorus-containing compound, in particular from phosphorus present as iron phosphate, from a dry mass, in particular from biogenic residues, by dry magnetic separation, and to a plant for carrying out the process.

BACKGROUND OF THE INVENTION

Biogenic residues offer several potentials, in particular nutrients, energy, phosphorus and metals, which are often underused by the current process chains. Biogenic residues are often only disposed of and not recycled.

The nutrients found in biogenic residues are often in a chemically unstable and aqueous form and are not worth transporting over long distances. Examples include liquid manure and fermentation residues.

The energetic potential of biogenic residues is the energy chemically bound in the complex organic molecules, which can be used as a biomass fuel to directly replace fossil fuels.

Another potential is phosphorus, an essential raw material that is neither replaceable nor renewable. Therefore, various processes for the recovery of phosphorus from biogenic residues with a phosphorus content are currently being developed.

Metals can be contained in the solids in different concentrations and combinations. Some metals are rare elements found only in small concentrations in the earth's crust. This includes, for example, cobalt, which is required in battery production for electromobility, so that the raw material is currently in high demand.

After all, the water bound in the form of moisture in the residues represents a valuable asset as drinking or process water.

Proceeding from this, the invention is based on the object of specifying a method with which phosphorus can be easily and effectively separated from dry matter in order to form it to make usable. Furthermore, the invention is based on the object of creating a system with which the method can be carried out.

DESCRIPTION OF THE INVENTION

To solve the problem, according to the invention, the phosphorus is removed from the dry matter by dry magnetic separation.

The method according to the invention is characterized by the following steps: a. providing a dry mass containing the magnetic, phosphorus-containing compound in the form of a powder and b. Subjecting the powder to a magnetic field so that the magnetic, phosphorus-containing compound is attracted by the magnetic field and separated from the remaining powder.

The phosphorus is chemically bound in magnetic compounds, in particular molecules or salts, and can be present in any oxidation state. For example, the phosphorus can be present as a salt of an oxo acid of phosphorus, in particular a salt of phosphoric acid H ₃ PO ₄ , phosphonic acid H ₂ PHO ₃ , phosphinic acid HPH ₂ O ₂ or the corresponding diphosphoric acids. Dihydrogen phosphates (primary phosphates) MΉ ₂ RO ₄ , hydrogen phosphates (secondary phosphates) M ₂ HPO ₄ or neutral phosphates (tertiary phosphates) M ₃ PO ₄ should be mentioned in particular as salts of phosphoric acid. Primary phosphonates MΉ ₂ RO ₃ and secondary phosphonates M ₂ HPO ₃ should be mentioned in particular as salts of phosphonic acid. Primary phosphinates MΉ ₂ RO ₂ and secondary phosphinates M ₂ HPO ₂ phosphinates are to be mentioned in particular as salts of phosphinic acid. In this case, M' denotes a magnetic metal of any valence (the above-mentioned empirical formulas of the compounds refer to a monovalent metal M ⁺¹ , for example). Particularly suitable as magnetic metals are the ferromagnetic metals iron Fe, cobalt Co and nickel Ni in any oxidation state. Iron phosphates, in particular iron(II) phosphates such as Fe 3 (PO 4 ) 2 and iron(III) phosphates such as FePO 4 , should be mentioned as particularly preferred magnetic compounds within the scope of the invention.

In the context of the invention, dry mass is understood to mean a mass whose moisture content is so low that it is no longer sticky. In particular, it is a free-flowing dry mass.

The dry matter is preferably obtained from residues. The term residue is understood broadly within the scope of the invention and does not include in particular exclusively biogenic residues. Biogenic residues are organic waste and waste water, agricultural and forestry by-products and biogenic production residues. In addition, the term residue for the description of the starting materials of this process includes all heterogeneous mixtures of substances with organic components. These include sewage sludge (primary sludge, secondary sludge, tertiary sludge, digested sludge) and also liquid manure, fermentation residues, pond or river sludge, and algae and other residues from marine plants and animals, as well as other organic mixtures of substances and secondary raw materials.

If the phosphorus present in the dry mass or the residue (as starting material for the dry mass) is not present in the form of a magnetic compound, the preparation of the dry mass in step a) can include a chemical conversion of the original phosphorus compound into a magnetic compound. For example, for this purpose, a suitable salt of a magnetic metal M′ or a solution thereof is added to the dry mass or the residue, so that the magnetic compound is formed. For example, an iron salt solution such as iron(II) chloride or iron(III) chloride can be used.

In the separation step, the magnetic, phosphorus-containing compound separated from the powder is preferably deposited on a magnet that generates the magnetic field or on an element magnetized by the magnet. In this way, the magnetic, phosphorus-containing compound is temporarily immobilized on the magnet or the magnetized element, which simplifies further separation. In this case, the magnetized element acts as a (temporary) store or storage container for the severed connection.

In a preferred embodiment, the method also includes step c. Switching off the magnetic field so that the magnetic phosphorus-containing compound deposited on the magnet or the magnetized element is released.

This ends the temporary immobilization of the magnetic connection so that it can be caught and transported away.

The magnetic field can be applied to the powder in various ways. It can take place statically, with the stationary powder being subjected to a magnetic field generated by a stationary magnet. Alternatively, the loading does not take place statically, with a relative movement between the powder and the magnet or magnetized element being generated by the powder or the magnet or the magnetized element is moved relative to each other. It is particularly preferred here that the powder is moved by the magnetic field or moves under the influence of gravity, with the magnetic field being generated by a preferably stationary magnet or stationary magnetized element.

The separation can be done, for example, by scattering a thin layer of the powdered dry mass onto a magnetically active base, by swirling (blowing) in front of a magnetically active magnetic plate, or in any other way that allows the magnetic, phosphorus-containing compound to be extracted from the dry mass extract the effect of the magnetic field. In the context of this description, “magnetically active” means an object that is in particular temporarily magnetized by a magnet or that is itself (permanently) magnetic.

According to a preferred embodiment of the method, the dry mass powder moves under gravity through a drop housing, i.e. it falls or trickles through the drop housing, and settles on an inner wall (= magnetized element) of the drop housing magnetized from the outside by the magnet. It is thus immobilized on the housing so that it is separated from the rest of the powder. The case housing can be designed, for example, as a down pipe, on the outer circumference of which the magnet or magnets is or are arranged.

Electromagnets or permanent magnets can be used as the magnet for generating the magnetic field. A plurality of 2, 3, 4 or more magnets can also be used. The magnetic field is preferably generated by at least one electromagnet, which particularly preferably magnetizes a housing wall, for example of a storage container, or the inner wall of the drop housing.

It is advantageous if, in step a), the powder of the dry mass, in particular the magnetic, phosphorus-containing compound contained therein, is provided with a maximum grain size of 100 μm. In this way, the individual magnetic phosphorus-containing particles are sufficiently small and light that they can be easily attracted and moved by a magnetic field. In this case, unavoidable larger impurities particles, such as larger inorganic or organic lumps or structures, such as metals, stones, pieces of wood or the like, can be tolerated since they do not impair the magnetic removal of the phosphorus compound.

In advantageous embodiments, the provision of the dry matter in the form of a powder in step a) includes grinding the dry matter, in particular to the maximum Grain size of 100 pm. Grinding is particularly advantageous in the case of a coarse-grained dry matter.

Any milling process can be used.

In a particularly preferred embodiment, the dry mass is ground with the aid of balls that are set in motion. The spheres are preferably mixed with the dry matter or a starting material from this (in particular biogenic residue) and set in motion therein, for example by means of a mixer.

The diameter of the balls is preferably between 5 mm and 50 mm, particularly preferably between 15 mm and 30 mm.

The spheres can be made of any material, with a certain water absorption capacity in the form of hygroscopicity and/or capillarity and strength being preferred. The balls are preferably made of wood and in particular beech wood. Alternatively, the spheres can be made of another material that has properties similar to wood, particularly in terms of moisture management and strength. For example, wood-plastic composites come into question.

The balls that are mixed in and set in motion allow the dry matter to be ground so that no mechanical grinder is required. However, as an alternative or in addition, a mechanical grinder (a mill, for example a cone or disk mill) can also be used to grind the dry matter.

According to an advantageous embodiment, the dry mass is ground while the dry mass is dried at the same time. In the case of the ball milling described above, balls made from a moisture-absorbing material, in particular from wood, are therefore advantageous. A drying medium can be passed through the bed of beads for the purpose of drying.

The powder fed to the separation step b) preferably has a dry residue content of at least 90% by weight, in particular at least 95% by weight.

The system according to the invention for separating a magnetic, phosphorus-containing compound, in particular iron phosphate, from a dry mass, in particular from biogenic residues, comprises: a grinding device (crushing device) for grinding the dry mass to a powder, in particular with a maximum grain size of 100 μm, and a separating device (magnetic separator) comprising at least one magnet for generating a magnetic field, the separating device being designed to apply the magnetic field to the powder so that the magnetic, phosphorus-containing compound is attracted by the magnetic field and separated from the (remaining) powder.

The system according to the invention is suitable and set up for carrying out the method according to the invention.

Preferably, the separating device (magnetic separator) has a drop housing that is open at the top and bottom and has at least one closed peripheral wall, with the at least one magnet being arranged outside the peripheral wall so that it is able to generate a magnetic field that acts in the interior of the drop housing.

Furthermore, it is preferred that the separating device comprises a swirling device for swirling the powder. The swirling device is designed or arranged in particular to swirl the powder in the magnetic field. Such a turbulence device promotes the attraction of the magnetic phosphorus compound in the magnetic field and its separation from the remaining dry mass powder.

The turbulence device can comprise a baffle plate arranged in the upper third of the case housing, onto which the falling powder trickles and is whirled up by the recoil.

The magnet can be an electromagnet or a permanent magnet.

As a special form of permanent magnet, a tubular magnet can be used for free-fall applications, as is also used in the pharmaceutical industry for separating weakly magnetized particles. Furthermore, a drum magnet, an overbelt magnet or other magnet systems can be used for separation.

The plant can further comprise a hopper which is used to feed the powder to the separating device. In particular, the funnel can be arranged above the case housing.

In a preferred embodiment, the grinding device comprises a mixer equipped with balls, in particular wooden balls, as already described in connection with the method. Such a ball milling device, which is not only suitable for milling but also for producing the dry matter from residues, and a corresponding method are described in detail further below. As an alternative or in addition to the ball milling device, the milling device can have a comminution device equipped with a mechanical grinder, for example a conical grinder or disk grinder, for comminuting the dry matter. The comminution device can be arranged above the separating device, in particular above the funnel.

The equipment may further include a container (storage) for receiving the residual powder separated from the magnetic phosphorus compound. The container can be arranged below the separating device, in particular below the drop housing.

Ball Milling Apparatus and Method

As already mentioned above, the dry mass can advantageously be obtained using a mixer (reactor, bioreactor) filled with balls. This will be described below.

The method, i.e. the provision of the dry mass in the form of a powder according to step a) of the method according to the invention, comprises the following steps in this embodiment: a1) filling biogenic residues with a liquid portion into a bioreactor, a2) drying the residues to a dry mass, a3) grinding the dry matter, a4) removing the dry matter.

During the grinding in step a3), the dry mass can be further dried.

According to a more specific description, the method has the following steps: a1) Filling the residues containing a liquid portion into a bioreactor filled with (preferably dry) balls and having a mixer and mixing the balls and the residues by operating the mixer at least intermittently during the filling and /or after filling, so that films of the residues form on the surfaces of the spheres, a2) drying the films of residues to form crusts of dry matter with a residual water content on the surfaces of the spheres by supplying a drying medium to the bioreactor, which Flows around balls, with at least part-time operation of the mixer, a3) grinding and further drying of the dry matter by at least part-time operation of the mixer with abrasion of powdery dry matter from the balls, a4) removal of the powdery dry matter from the bioreactor. The result of the process is a very dry and very finely divided powdery dry mass (hereinafter also simply referred to as powder), which can be used in a variety of ways depending on the starting material (the residue).

According to the invention, the method allows the phosphorus contained in the residue to be recovered and used in particular as fertilizer. For this purpose, the dry mass obtained is subjected to the dry magnetic separation according to the invention in order to separate it from the remaining powder.

Furthermore, after the phosphorus has been separated off, the powder can be used in particular as a substitute fuel for fossil fuels, in particular wherever a combustion process using fossil fuels, in particular coal, is currently taking place. An example is the cement industry when burning clinker. In this way, fossil CC> ₂ emissions can be effectively reduced.

Furthermore, after the phosphorus has been separated off, the dry matter can be used as (nutrient-rich) fertilizer in agriculture in the form of dry meal, in particular through the targeted mixing of chemically unstable manure or fermentation residues with particularly dry biogenic residues, whereby the nutrients of the residue are used.

Furthermore, a concentrated discharge of nitrogen via the gas phase is possible, which enables the isolated recovery of nitrogen via an acid scrubber.

In addition, metals can be extracted from the residues in order to be used as raw materials in the production processes of goods.

Finally, the water discharged from the reactor with the drying medium by the process can be used later by being treated as industrial or drinking water. By drying seawater, two recyclable materials are produced simultaneously: salt as dry matter and water by separating the water from the drying medium with subsequent processing to make drinking or process water.

With the method according to the invention, all of the potentials of the residue described in the introduction can thus be used.

The term residue is understood broadly within the scope of the invention and includes in particular, but not exclusively, biogenic residues. Biogenic residues are organic waste and waste water, agricultural and forestry by-products and biogenic production residues. In addition, the term residue for the description of the starting materials of this process includes all heterogeneous mixtures of substances with organic components. These include sewage sludge (primary sludge, secondary sludge, tertiary sludge, digested sludge) and also liquid manure, fermentation residues, pond or river sludge, seawater and algae as well as other residues from marine plants and animals, as well as other organic mixtures of substances, secondary raw materials and industrial sludge.

During the grinding in step a3), the dry mass can be further dried.

According to an alternative embodiment, the process comprises two stages, the first stage also being referred to as the “wet” stage and the second stage being referred to as the “dry” stage. During the “wet” stage, the films of residues are essentially dried, with the formation of crusts on the surfaces of the balls, with at least intermittent operation of the mixer, which also causes the powder to be separated from the balls. During the "dry" stage, the grinding and further drying of the powdery dry matter already separated from the spheres is carried out by operating the mixer through the grinding action of the spheres and discharging the powdery dry matter from the bioreactor. The "dry" stage, which includes further drying and grinding, can be carried out as an independent process and in addition to the first stage.

In a preferred embodiment of the invention, the drying medium is a drying fluid, in particular a gaseous fluid. Within the scope of the invention, warm, unsaturated air and/or unsaturated, superheated steam are preferably used as gaseous drying fluids. The application of the principle of steam drying using superheated water vapor also leads to a significant increase in the efficiency of heat transfer and thus time savings compared to using warm, unsaturated air as a drying medium. The principle of steam drying using superheated steam at atmospheric pressure is known per se.

The drying process is accompanied by the evaporation of liquid, especially water (moisture). The evaporation of liquids is defined as a phase change from the liquid to the gaseous phase and thus the conversion of the liquid into vapor. From a thermodynamic point of view, steam is a real gas that can be discharged from the reactor space, which in the present case takes place through the drying medium. The term evaporation is a generic term that very generally describes the phase transition from the liquid to the gas phase and thus includes evaporation below the boiling point and boiling above the boiling point of a liquid.

Water vapor can be part of a gas mixture. Thus, the water vapor in the atmosphere is part of the gas mixture of humid air. Moist air is a mixture of dry air and water. Compared to other mixtures of ideal gases, humid air has the special feature that water vapor cannot be mixed with dry air in any desired quantity. The amount of water vapor that can be contained in the air is such that the partial pressure of the water vapor (partial pressure) has reached the saturation pressure. If the partial pressure of water vapor is less than the saturation pressure, then the air is unsaturated.

Steam with a temperature higher than the saturation temperature is unsaturated, superheated steam. On the one hand, water vapor in the unsaturated moist air below the boiling point is superheated vapor. On the other hand, a vapor can appear completely isolated and fill a space alone, especially if the vapor is kept above the boiling temperature.

In order for a liquid to turn into vapor, it must be supplied with heat of vaporization (thermal energy), because with vaporization u. a. there is a significant increase in volume. The increase in volume during the evaporation of water at a pressure of 1 bar is more than 1600 times. If one considers an isobaric vaporization, the heat of vaporization is an enthalpy of vaporization. The energy input required for the transition from 1 kg of water to water vapor at atmospheric pressure (1013.25 hPa) and 100 °C is 2257 kJ.

The energy can be introduced by convection (in the present inventive case using the drying medium) and/or conduction (via hot contact surfaces, e.g. heated outer walls of the bioreactor according to the invention) and/or by radiant heat (e.g. through transparent outer walls of one described later). bioreactor according to the invention).

In addition, the supplied biogenic residues can preferably be heated before the supply (maximum up to the boiling point).

The intensity and combination of the various heat transfer processes depend on the material properties of the biogenic residue to be dried and the desired drying result, which also includes disinfection/sanitization. Preferably, heat transfer by convection is used with the aid of the drying medium.

In addition to this, further process parameters, in particular the temperature and the pressure (negative pressure/vacuum, positive pressure) can be additionally varied for optimal process control and product quality, since these parameters directly influence the drying process. So the boiling temperature is a dependent function of the set pressure levels. Temperatures above 0° C. up to 250° C. and positive (overpressure) or negative (negative pressure) pressure differences of 0-4 bar in relation to atmospheric pressure are preferably set.

The spheres can be made of any material as long as it has sufficient water absorbency in terms of hygroscopicity and/or capillarity and strength. The balls are preferably made of wood and in particular beech wood. Alternatively, the spheres can be made of another material that has properties similar to wood, particularly in terms of moisture management and strength. For example, wood-plastic composites come into question.

In order to achieve an additional, rapid removal of moisture from the residual material film that settles on the surfaces (hereinafter also referred to as biofilm) through sorption and additional capillary forces in the balls, these can be dried before filling or feeding in the residual material. This can be done in particular by feeding the drying medium, in particular warm, unsaturated air and/or unsaturated, superheated steam, into the reactor.

A mixing process can be carried out while the residues are being filled in. At least one mixing process is preferably carried out after filling. As a result, the residues are completely mixed with the balls at least once.

The mixing process or processes continue until uniform thin films of the residues have formed on the surfaces of the balls.

In order to fix comparatively dry residues on the surfaces of the balls and to form the films on the surfaces of the balls, liquid can also be applied to the surfaces of the balls when filling the residues. In this way, the dry residues are slurried or slurried and adhere stably to the ball surfaces. The liquid can be introduced in particular by spraying in the liquid in the form of a spray mist. The liquid can be water or another (biogenic) residue with a higher moisture content. This means that drier and wetter residues that are fed in at the same time can be fixed to the surfaces of the balls as thin biofilms.

According to one embodiment, liquid manure or fermentation residues are used as further (biogenic) residues with higher moisture contents. Through a targeted mix of chemically unstable liquid manure or fermentation residues with very dry, preferably biogenic residues, a nutrient-rich fertilizer mixture can be produced as dry meal and thus as a dry stabilizer using the process presented here.

Additional liquid is preferably introduced when the moisture content of the residue used falls below a lower threshold.

The liquid supplied can be enriched with an iron salt in order to precipitate free phosphates in the residue as iron phosphate.

Furthermore, the liquid can contain lime (calcium carbonate CaCOs) and can be added, for example, in the form of milk of lime and evenly distributed on the spherical surfaces.

Alternatively, lime can also be fed into the bioreactor as a solid, in particular in the form of a free-flowing powder. The addition of lime increases the pH value of the biofilms that form on the spherical surfaces, which enables a targeted reduction in the temperature level, which is necessary for the phase transition of nitrogen, which is mostly available in the form of ammonium in the biogenic residues, from the liquid to the gaseous phase is required.

This means that the gaseous discharge of ammonia (NH3) can be specifically influenced with the help of the drying medium. The gaseous nitrogen that is discharged as a result can then be processed further and thus separated as a nutrient. This can preferably be done with an acid scrubber using sulfuric acid (H2SO4) so that ammonium sulphate solution can be produced.

In the case of drying using warm, unsaturated air as the drying medium, the warm, unsaturated air is preferably introduced into the bioreactor at a temperature of up to 85°C. The introduced air then flows around the spheres, with the films adhering to the sphere surfaces releasing moisture into the air. The saturated air is discharged from the bioreactor again. Optionally, the water contained in the saturated air can be used for other purposes.

For drying using unsaturated, superheated steam as the drying medium, the unsaturated, superheated steam is introduced into the bioreactor in particular at a temperature of 110° C. to 300° C., preferably 110° C. to 250° C. The set process parameters can be varied with regard to pressure and temperature, taking into account the limit values for the gas phase, which are derived from the vapor pressure curve. Preferably, the water vapor at Atmospheric pressure introduced into the bioreactor. The superheated steam then flows around the balls. The residues absorb the heat convectively. The films adhering to the surfaces of the spheres, which have a liquid content, evaporate moisture, which the superheated steam absorbs as a real gas. The moisture removed from the biogenic residues thus becomes excess steam, which is discharged from the bioreactor again. Optionally, the water contained in the discharged excess steam can be used for other purposes.

As a result of the drying, crusts form on the surfaces of the balls, which consist of dry matter with a residual water content. Due to the mixing processes, the crusts are finely ground (rubbed off) from the surfaces of the spheres and will settle as a powder (powdery dry matter) with a residual water content at the bottom of the bioreactor.

During drying, the drying medium is preferably supplied via a plurality of drying medium inlets arranged at different heights of the bioreactor, in particular a drying medium inlet arranged in the lower third of the bioreactor, a drying medium inlet arranged in the middle filling level area, a drying medium inlet arranged above a maximum filling level and a drying medium inlet arranged in the bottom area . When a crust starts to form on the surfaces of the balls, the drying medium supply in the lower area of the bioreactor, in particular from the drying medium inlet arranged in the lower third of the bioreactor and the drying medium inlet arranged in the bottom area, can be reduced or switched off. The result of this is that the drying medium no longer flows through the powdery dry mass accumulating in the floor area. This prevents the highly flammable powder from being whirled up and discharged with the exhaust air or excess steam. This measure therefore serves not only to retain the powder in the reactor, but also to protect against explosion.

The powder at the bottom of the bioreactor is preferably dried indirectly, with the drying medium not flowing through it directly (“aeration”). The indirect drying can take place via the surfaces of the balls, in particular by sorption and additional capillary suction forces, which are located in the powder mixture in the bottom area of the bioreactor and are preferably drier than the powder surrounding them.

Without whirling up the powder in the bottom area of the bioreactor, the drying medium can flow around the balls located above the powder during grinding and to be dried in the process. For this purpose, the drying medium is in particular supplied via the drying medium inlet arranged in the central filling level area and the drying medium inlet arranged above the maximum filling level, while the drying medium is not supplied via the other drying medium inlets.

Through the sorptive removal of water molecules in combination with the grinding of the powder, agglomerates are broken up and particles of the ground material are successively reduced in size.

The reduction in size of the individual particles in the form of agglomerates is determined and limited, among other things, by the water molecules, which act as adhesive liquid bridges between the particles. By removing the water molecules, the particles can be increasingly isolated down to the single-digit pm range.

Indirect drying via the surfaces/boundaries of the spheres also preferably allows powder to be dried cold, in that fully dried spheres are mixed into a powder bed, with the temperatures of the spheres and the powder not exhibiting any large temperature differences. As a drying result, with indirect drying, a complete drying of powder with a dry residue content of up to 98% can be achieved.

The spheres and powder are preferably mixed intermittently. The mixing processes grind the powder through the friction on the surfaces of the balls.

For thermal hygienization of the (biogenic) residues, the residence time of the biogenic residues in the bioreactor can be set for a predetermined period of time, which is based on the respective legally valid specifications for hygienization.

A bioreactor that is set up to carry out the preferred method according to the invention for providing the powdered dry mass has the following features: a housing with at least one base and a preferably closed peripheral wall, a mixer preferably mounted on the base so that it can rotate about a vertical axis, the is arranged inside the housing, at least one drying medium inlet arranged in the central area or in the middle in the peripheral wall of the housing, based on a height of the housing or on a maximum fill level (Hiu _ax ) of the housing, at least one drying medium outlet, a filling of the bioreactor made up of a large number of balls, with an initial filling level

(Hstart), at least one supply line for residues, and at least one discharge device for removing the dried residues.

Another desiccant inlet can be located in the bottom or in the peripheral wall. A cumulative arrangement in the base and in the peripheral wall can also be provided.

A plurality of drying medium inlets can be provided in the peripheral wall and also in the base in order to ensure an adequate supply of drying medium. In particular, the bioreactor can comprise a plurality of drying medium inlets, in particular a drying medium inlet arranged in the lower third of the bioreactor in the peripheral wall, the drying medium inlet arranged in the middle filling level area in the peripheral wall, a drying medium inlet arranged above the maximum filling level in the peripheral wall or a cover and/or one drying medium inlet arranged in the floor.

The drying medium can be fed in and distributed in a punctiform manner and/or via distributor plates which each have a large number of holes and extend over at least part of the reactor cross section. This means that drying medium can be supplied and distributed over defined areas.

The housing can preferably be covered by a cover. In this case, the residues are preferably supplied and the drying medium is removed through the cover, in which corresponding openings are provided. Alternatively, the drying medium can be discharged and the residues can be fed in through the lateral peripheral wall above the maximum fill level by providing appropriate openings.

Irrespective of the design of the bioreactor, with or without a cover, the residues can also alternatively be fed into the lateral peripheral wall below the surface of the maximum filling level, preferably with a screw. In itself, it is irrelevant from where or at which point the biogenic residues are fed into the bioreactor. The mixer is preferably a vertical screw. The vertical screw can preferably be conical or cylindrical. At least one knife and a scraper bar at the beginning of the worm can preferably also be attached to the worm windings or worm wings (segmented worm). The mixer is preferably mounted on the bottom of the housing.

The housing is preferably of cylindrical or conical design.

The housing is preferably thermally insulated in order to avoid energy losses and, if necessary, to be able to keep the temperature in the bioreactor constant during the drying process.

The exhaust air or excess steam can be removed from a closed bioreactor by internal pressure or by applying a negative pressure. The applied temperatures can be varied by varying the applied pressures. In the case of a negative pressure, the temperature can be lowered and in the case of an overpressure, the temperature can be increased. The construction of the bioreactor is to be designed with a lid according to the selected pressure conditions.

The individual process steps are explained in more detail below.

(a1) Filling in residues with a liquid content

The aim of the first process step is the even distribution of the supplied (biogenic) residues on the surfaces of the spheres in the form of thin films with a layer thickness of preferably a few millimeters.

For this purpose, the residues are preferably fed into the bioreactor above the bead bed.

The balls are preferably made of wood, in particular beech wood. Alternatively, other moisture-regulating substances that have sufficient strength on the surfaces can also be used. The diameter of the spheres can preferably be between 5 and 50 mm. For example, around 73,000 balls with an average diameter of 25 mm are used per cubic meter of volume used in the bioreactor. The sum of the spherical surfaces per cubic meter is 144 m ² (square meters).

From a geometric point of view, spherical bodies are preferably used for carrying out the method. Alternatively, preferably round or oval shaped bodies can also be used.

The residues are preferably fed in while the mixer is operated at least intermittently in order to bring about a mixing process of the balls and residues. Of the The mixing process should preferably last several minutes so that an even film can form on all balls. The mixing process takes place in the bioreactor, preferably by means of a vertical screw.

The supplied residues can have different material properties and particle sizes. A supplied mixture can consist of liquid, wet, moist, sticky, solid, crumbly and powdery fractions at the same time. The size of the solid particles supplied can also vary in a range from 1 μm in a suspension to several centimeters as solid lumps.

If residues with dry fractions that have a water content of <70% are fed in, water is preferably filled into the bioreactor in order to pre-slurry or slurry the dry fractions. This can preferably be done by a spray mist above the balls and during the mixing process.

Another special feature of the supplied residues, in particular biogenic residues, is the phosphorus they contain. Since the phosphorus is to be separated, obtaining a fuel which has been depleted in phosphorus, the availability of the phosphorus in the form of the magnetic, phosphorus-containing compound (see above) in the residues is necessary, which enables the magnetic substance separation according to the invention.

If the phosphorus contained in the (biogenic) residue is present in the form of a non-magnetic compound or in dissolved form, a suitable magnetic reagent, in particular in an aqueous solution, for example an iron salt solution, can be supplied to the bioreactor. The supply is preferably in the form of a spray above the balls during the mixing process during the supply of residues. The supplied aqueous solution is mixed evenly into the films by the mixing process and then, in the presence of phosphorus dissolved in the aqueous films, leads to the formation and precipitation of a corresponding magnetic, phosphorus-containing compound, for example iron phosphate, within a few minutes. This can be magnetically separated from the powdered dry mass produced and fed to subsequent processing.

A further differentiation with regard to the supplied biogenic residues is the degree of chemical instability of the organic part. This easily degradable fraction of organic matter, consisting of energy-rich complex organic fat and protein molecules, should preferably be quickly converted into a stable form in order to preserve the chemically bound energy and minimize odors. One form of stabilization is the conversion to the state of a dry stabilizer. Due to the lack of water, the transport of nutrients is prevented for the mostly heterotrophic bacteria, which very quickly begin to break down the organic components, and thus the biological breakdown of the easily degradable organic substances is effectively stopped.

Therefore, the balls are preferably dried before filling. As the wet film spreads on the surfaces of the spheres, water is drawn from the wet film via capillary attraction forces across the sphere interfaces from the outside in into the drier cell cavities of the spheres as free water. The film is dried by removing moisture from the inside and is stabilized by the dry rigidity that accompanies it.

In principle, the hygroscopic property of the balls allows the humidity to be adapted to the prevailing external conditions. The associated ability to store moisture enables very aqueous suspensions to be fed into the bioreactor, the water content of which can be absorbed up to the saturation limit of the balls.

As a result of this process step, all balls located in the bioreactor are covered with a thin film.

(a2) Drying of the residues to a dry mass

The biogenic residues, which are present in the form of wet films on the balls, are dried by supplying a drying medium, preferably at a temperature above room temperature to 85 °C using warm, unsaturated air as the drying medium and preferably at a temperature above 110 °C C when using unsaturated, superheated steam as a drying medium. The drying medium is preferably supplied at a number of points which are arranged at different heights of the bioreactor. The drying medium is preferably supplied from the bottom of the reactor, from its peripheral wall, namely in the area of the balls at the height of the powder accumulation and in the area of the balls above the powder accumulation, and above the bed of beads.

When warm, unsaturated air is used as the drying medium, the aqueous surfaces of the films dry in this phase primarily by releasing water as water vapor into the unsaturated warm air flowing around them, and water is thus discharged from the bioreactor as water vapor via the more saturated exhaust air. When using unsaturated, superheated water vapor as a drying medium, the aqueous surfaces of the films dry in this phase mainly by releasing water as water vapor in the form of a real gas into the unsaturated, superheated water vapor flowing around them, and water is thus discharged from the bioreactor as excess vapor.

The preferred mechanical intermixing of the spheres leads to an increase in the wet surfaces, in that the wet films transfer moisture to drier films and, after mixing, are again formed into homogeneous wet biofilms.

If no fresh residues are fed in, the wet films dry out and dry matter develops in the form of dry crusts (dry matter with residual moisture) on the surfaces of the wooden balls.

The dry crusts should preferably increase the diameter of the balls by 5% up to 10%. This increases the volume used in the reactor by up to 33%. The filling density of the spherical matrix is around 60%, so that a free volume (air volume when using warm, unsaturated air as drying medium and steam volume when using unsaturated, superheated steam as drying medium) of around 40% remains.

When crust formation begins or when the moist films change to superficially dry crusts, but at the latest after crust formation is complete, the supply of drying medium to the lower area of the reactor is reduced or interrupted, so that the supply of drying medium is essentially only in the area of the balls above the one now in the lower one Reactor area accumulating powdery dry matter takes place.

(a3) Grinding and drying of the dry matter

The dry mass adhering to the surface of the wooden balls is rubbed off or ground down as a trickle by friction through mixing processes. Most of the trickling substances settle on the bottom of the bioreactor.

As free trickling substances become increasingly available, the mixing processes lead to the trickling substances being ground into a micro-fine powder. As a result, the particle size is less than 100 μm and preferably less than 60 μm. Individual particles are ground down to the single-digit pm range.

With the transition from the wet phase to the dry powder phase, the dry mass is further dried. However, the type of drying changes. The powder is no longer direct via the drying medium, but indirectly via the capillary suction forces and sorption at the dry interfaces of the spheres. The water in the powder is therefore transported via the boundary surfaces of the spheres by sorption and capillary forces of attraction from the outside inwards into the cell cavities of the spheres and is bound there.

For this purpose, the part of the balls not covered by powder, which is above the layer of powder deposited on the ground, continues to be dried by the drying medium, when using warm, unsaturated air as the drying medium by the warm and unsaturated air flow, and when using unsaturated, superheated steam as the drying medium dried by the superheated and unsaturated steam stream. A subsequent mixing process mixes very dry balls from the upper area into the powder in the lower area of the bioreactor. In addition, the balls that are in the powder and that have previously been enriched with water from the powder are mixed from the powder into the upper part of the bioreactor and thus above the powder layer into the balls located there.

As the drying continues, water is removed from the powder, which then enables further grinding of the powder because the water, which acts as a binder, is increasingly removed. The final dry residue content of the powder should preferably be between 90% and 98% by weight, i.e. have a moisture content of at most 10% by weight and up to 2% by weight.

The grinding process is preferably carried out until the balls are essentially free of dry matter, i.e. the crusts are largely removed.

Then the supply of drying medium is completely interrupted and the operation of the mixer is stopped. The drying medium is discharged at a reduced level in order to maintain a continuous negative pressure.

(a4) Removal of the dry matter

The powder can preferably be carried out of the reactor pneumatically with the drying medium, in particular by suction air or negative pressure with the aid of cyclones. Heavier contaminants can be easily separated in the flow of the drying medium, especially in the air flow, using the air separation process.

Alternatively, the powder can be discharged via a discharge device comprising lateral openings or openings in the bottom area of the reactor. Preferably, a sieve device, in particular a perforated plate or a grid or bars, can be arranged in front of the openings in order to at least remove the balls and optionally coarser components retain dry matter. A device for selectively opening and closing the discharge device can also be arranged in front of the screening device on the inside of the housing.

The discharged dry matter is then subjected to the process according to the invention for separating the magnetic, phosphorus-containing compound and, if necessary, to further processes for quality assurance. However, dry matter produced in other ways can also be fed into the phosphorus separation process.

Iron phosphate is paramagnetic and is present in particular in particle sizes from 5 μm to 50 μm. In order to enable the magnetic, phosphorus-containing compound, for example iron phosphate, to be separated from the hygroscopic bulk material in powder form, the dry mass is preferably comminuted to a maximum size of 100 μm with a simultaneously high dry residue content of more than 90% up to 98%. The magnetic, phosphorus-containing compound is present in particular in particle sizes from 5 μm to 50 μm. These two parameters, particle size and dry residue content, are advantageous in order to achieve free-flowing flowability and avoid clumping in the powder. When setting the parameters, there are smooth transitions and consequently gradual differences in terms of the degree of separation depending on the magnetic field strength. In addition, clumping has a direct impact on the degree of purity of the separated magnetic iron phosphate particles, since foreign matter adheres with increasing clumping.

The grinding of the dry mass for the purpose of separating off the phosphate can be carried out in a mill or generally in a comminution unit. The device should enable the particles to be reduced to a grain size of <100 μm.

A purely mechanical comminution of the particles is limited by the residual moisture in the dry matter. If the residual moisture in the externally supplied or discharged dry matter is too high, comminution can be inhibited down to the single-digit pm range. A further preferred alternative process control is then the supply or return of the externally supplied or discharged and preferably comminuted dry matter in the process phase (a3) grinding and drying the dry matter until the necessary dry residue content is reached, which means comminution down to the preferably single-digit pm range allows.

Alternatively, the drying and grinding of externally supplied or discharged and preferably pulverulent dry mass can preferably take place or be continued in a second, separate mixer as an independent process. An exemplary embodiment of the invention for the expanded method using biogenic residues with a liquid content as starting materials is to be explained in more detail below with reference to drawings. Show it:

FIG. 0 shows a schematic representation of an unfilled bioreactor as a grinding device according to an embodiment of the invention;

FIG. 1 shows a schematic representation of the bioreactor from FIG

Spheres that are clean (unwetted) on the surface with a fill level Hstan;

FIG. 2 shows a schematic representation of the _bioreactor from _FIG .

FIG. 3 shows a schematic representation of the _bioreactor from FIG.

FIG. 4 shows a schematic representation of the bioreactor from FIG. 0 with filled balls, which are clean again on the surface, and with powder deposited on the bottom of the container, with a minimum fill level Hp _UiVer ;

FIG. 5 shows a schematic representation of a plant for separating a magnetic, phosphorus-containing compound, in particular iron phosphate, in a state with excited magnets; and

FIG. 6 shows a schematic representation of the system from FIG. 5 with deactivated magnets.

The bioreactor shown in FIGS. 0 to 4 represents an example of a grinding device that can be used advantageously within the scope of the invention for providing a powdered dry mass. The figures show different process stages for the preparation of the dry mass.

The bioreactor 0 is a thermal dryer which, in the exemplary embodiment shown in FIG. 0, consists of a housing 1 which is open at the top and which is conical in shape and essentially consists of a closed peripheral wall 1.2 and a base 1.1.

The schematic representation does not show that the housing 1 of the bioreactor 0 can be thermally insulated in order to avoid energy losses and to be able to keep the temperature inside the bioreactor 0 as constant as possible. In the bottom 1.1, a preferably conical screw 2 is rotatably driven about the vertical axis A. The screw 2 has at least one turn 2.1. The snail 2 is shown shortened here. Their axial length preferably extends up to the maximum fill level H _max in order to enable the quickest and most rapid mixing possible.

In the bottom 1.1 and in the peripheral wall 1.2 there are supply lines 6, 6.1, 6.2 and 6.3 for the drying medium, which is preferably ambient air and/or unsaturated, superheated steam, which is fed into the interior of the bioreactor 0, which allows the drying of the biogenic Residues 4 is used. In relation to the maximum fill level H _max of the housing 1, the feed line 6 is in the lower third, the feed line 6.1 is in the middle and another feed line 6.2 is above the bead bed (see FIG. 1). The supply line 6.3 is located in the floor 1.1. When using warm, unsaturated air as a drying medium, the ambient air can preferably be heated to a temperature in the range from 20 °C to 85 °C. If unsaturated, superheated steam is used as the drying medium, the unsaturated, superheated steam can preferably be heated to a temperature in the range from 110 °C to 250 °C.

Before the operation for drying biogenic residues can begin, a large number of balls, here wooden balls 3, which are preferably made of beech wood with a diameter of preferably 5-50 mm as bulk material, are inserted via the upper opening shown in Figure 0 into the bioreactor 0 to filled to a level of Hstan.

As soon as the wooden balls 3 have been filled into the bioreactor 0, the bioreactor 0 can be closed with a cover 1.3, which is shown in FIG.

The structure of the bioreactor 0 shown in FIG. 1 corresponds to that of the bioreactor 0 according to FIG. The supply lines for biogenic residues 4 and water 5 and the discharge line for the exiting drying medium 7 lead through the cover 1.3.

Before biogenic residues 4 are filled into the bioreactor 0, the wooden balls 3 are preferably dried in order to create a high potential in the wooden balls 3 for absorbing moisture.

The drying medium is preferably supplied via all supply lines 6, 6.1, 6.2 and 6.3 in order to introduce heat into the bioreactor 0 for drying. Preferably, the drying medium is warm, unsaturated air and/or unsaturated, superheated steam. The supply of warm air and/or steam via the supply line 6.3 serves as leakage medium (leakage air and/or leakage steam) for discharging the saturated air and/or the Excess steam from the lower part of the bioreactor 0, which and / or has previously flowed through the spherical matrix. The exhaust air and/or the steam is discharged via the discharge line 7 in the cover 1.3. A slight negative pressure is preferably set in the bioreactor 0 by the air streams and/or steam streams. The aeration and deaeration and/or the steam supply and steam removal preferably take place continuously. The specific design of the air supply and/or the steam supply with regard to the duration, the volume flow and the temperature with regard to the individual air supply lines and/or steam supply lines 6, 6.1, 6.2 and 6.3 is variable with the aim of obtaining optimal conditions for the drying process.

Thereafter, the vertically arranged screw 2 is put into operation in rotation and, preferably at the same time, the biogenic residues 4 are fed in via the feed line in the cover 1.3. The mixing process leads to the biogenic residues 4 being mixed with the wooden balls 3 and preferably lasts several minutes. The mixing process ends with largely homogeneously formed biofilms on the surfaces of the wooden balls 3.

In the event that the supplied biogenic residues 4 are too dry and the formation of biofilms is thus inhibited and therefore not sufficient, water 5 is preferably fed into the bioreactor 0 via a feed line in the cover 1.3 during the mixing process. The dry fractions of the biogenic residues 4 are thus slurried and slurried. The biogenic residues 4 enriched with water 5 then successively form biofilms on the surfaces of the wooden balls 3 during the mixing process.

If phosphorus is still available in the supplied biogenic residues in the form of dissolved phosphates or the like or in the form of non-magnetic compounds and is to be separated after the drying process, a suitable magnetic reagent is added, which converts the phosphorus into a magnetic compound. For example, an iron salt is added to the water 5 during the mixing process, so that phosphates dissolved therewith are spontaneously precipitated as iron phosphate in the wet biofilms.

The bioreactor 0 shown in FIG. 2 shows the state after the successful formation of biofilms on the surfaces of the wooden balls 3. The fill level in the bioreactor 0 rises to H _wet due to the biofilms.

In the further process, the wet biofilm is dried. As described above, the drying takes place by supplying warm air and/or unsaturated, superheated water vapor into the spherical matrix via the surfaces of the biofilms, preferably continuously via all air supply lines and/or steam supply lines 6, 6.1, 6.2 and 6.3. With Air saturated with water vapor and/or the excess steam is discharged via the exhaust air line and/or the steam discharge line 7 in the cover 1.3.

The operation of the auger 2 is preferably intermittent. For this purpose, the screw 2 is preferably stopped for around 3 to 60 minutes, particularly preferably 30 to 60 minutes, and then started to rotate for preferably 10 to 30 seconds. The intervals chosen are directly dependent on the heat energy fed into the bioreactor for drying. If unsaturated, superheated steam is supplied as the drying medium, the mixer can preferably be operated quasi-continuously. The biofilms on the surfaces of the wooden balls 3 are homogenized by the mechanical friction process, so that the moisture in the biofilms is distributed largely evenly on all ball surfaces and the effective surface area for evaporation is thus optimized.

The aim of the drying process is the formation of solid, dry crusts 4.1 of solids on the surfaces of the wooden balls 3. The crusts should increase the diameter of the wooden balls 3 preferably in the range from 5% to 10%. This reference value enables the calculation of the mass of solids to be fed preferably and thus also the fresh mass of biogenic residues.

The biogenic residues are preferably fed in in several partial portions. In this case, each additional partial portion of biogenic residues 4 is preferably supplied after the biofilms on the wooden balls 3 have partially dried, which have formed as a result of the biogenic residues 4 being supplied.

When the biogenic residues 4 have been fed in, the biofilms are dried so that solid, dry crusts form on the surfaces of the wooden balls 3 .

FIG. 3 shows the bioreactor 0 filled with wooden balls 3 on which solid, dry crusts 4.1 have formed. The filling level has fallen slightly and results in _hedging.

For the further drying process, the bottom ventilation and/or the steam supply line 6.3 and the lower lateral ventilation and/or steam supply line 6 are now switched off in order to prevent increasingly settled powder 4.2 from being stirred up in the bottom area of the bioreactor 0. The aeration and/or supply of steam takes place through the ball matrix, preferably continuously with supplied warm air and/or supplied unsaturated, superheated steam via the air line and/or steam supply line 6.1. In addition, preferably leakage air and / or leakage steam via the air supply line and / or Supplied steam supply line 6.2 and continuously discharged the exhaust air and/or the excess steam via the exhaust air line and/or steam discharge line 7.

The operation of the auger 2 is also preferably intermittent. For this purpose, the screw 2 is preferably stopped for around 3 to 60 minutes, particularly preferably 30 to 60 minutes, and then started to rotate for preferably 10 to 30 seconds. The dry crusts 4.1 on the surfaces of the wooden balls 3 are successively removed by friction as a result of the mechanical friction process. For the most part, the abrasion takes place directly in the form of coarse and fine powder particles 4.2, which largely settle in the bottom area of the bioreactor. The coarse and partially fine powder particles 4.2 already in the bioreactor are ground into a fine powder by friction between the surfaces of the wooden balls 3, which has a grain size of less than 100 μm.

The process of separating the powder particles is supported by drying the powder in addition to the grinding process. Since the initially dry particles lose their low residual moisture content and thus become powder-dry, a gradual separation of particles that were previously adhesively bonded with water is made possible.

The powder drying process takes place indirectly via the surfaces of the wooden balls 3 by capillary suction forces, which compensate for small moisture differences between the powder particles and the surfaces of the wooden balls 3 .

When wooden balls 3, which were previously dried in the upper area of the bioreactor 0, get into the powder 4.2 located in the bottom area 1.1 of the bioreactor 0 due to the mixing process carried out at intervals, the powder particles 4.2 are dried indirectly by sorption and capillary suction forces to compensate for the differences in moisture the interfaces of the drier surfaces of the wooden balls 3 and the wetter surfaces of the powder particles 4.2.

When wooden balls 3, which have previously absorbed moisture in the powder 4.2, reach the upper area of the bioreactor 0, the wooden balls 3 are dried directly by the warm air and/or the unsaturated, overheated steam.

Due to the mixing process at intervals, drier and wetter balls 3, in particular wooden balls, are exchanged at intervals between the upper region of the bioreactor 0 and the powder 4.2. This allows the powder 4.2 to be dried with a dry residue content of up to 98% by weight and thus a water content of around 2% by weight. FIG. 4 shows the bioreactor 0 filled with wooden balls 3, the surfaces of which have been freed from solids, and powder 4.2 on the bottom 1.1 of the bioreactor. The level has dropped slightly to a level Hp _UiVer .

The powder 4.2 can now be drawn off via the discharge device 8. In principle, the powder 4.2 can be discharged in any desired manner.

In addition to the fine powder with a diameter < 100 μm, there is often a proportion of up to around 15% of the total weight of larger particles. This is dry matter in the form of spherical particles or other forms, which are also discharged via the discharge unit 8 as free-flowing substances. The size of the discharged solid particles depends on the selected discharge device and can range from 1 mm to several centimetres. Thus, the powder 4.2 of the dry matter 4.1 is often present as a heterogeneous mixture of particles with small diameters and coarser components with a diameter >100 μm.

The powdery dry mass 4.2 including the coarser components is therefore advantageously discharged pneumatically by suction air and/or vacuum and the coarser components are then separated from the air flow and/or extracted gas flow (steam flow) with the aid of cyclones. To separate the two fractions, an air classifying baffle may be used in the air flow and/or gas flow.

A perforated plate is preferably provided as a sieve in front of the discharge opening in the peripheral wall 1.2 of the bioreactor 0. In this way, the maximum size of the particles discharged from the container can be determined and the wooden balls 3 can thus be held back. The perforated perforated plate is preferably protected from the rotating balls by a cover on the inside of the peripheral wall 1.2 of the bioreactor 0. If the holes are not covered, the holes will be clogged with liquid from the supplied biogenic residues and then harden. An opening is then only possible mechanically with a drill or a chisel. This procedure also applies analogously to other discharge devices, which therefore preferably have to be protected by a cover to the interior of the bioreactor.

The reactor 0 described above can be part of the plant according to the invention for separating the magnetic, phosphorus-containing compound 4.3 from the dry matter 4.1. be and embodies the grinding device for grinding the dry matter 4.1 to a powder 4.2. The dry matter 4.1 in the form of a powder 4.2 thus obtained in the reactor 0 is then subjected to a separation device for magnetic separation of the magnetic, phosphorus-containing compound supplied. This separation device is described in the following FIGS. 5 and 6 by way of example.

FIG. 5 shows such a separator for separating magnetic particles, in particular iron phosphate. The separator includes an optional crushing unit 20, a funnel 21, a fall housing (down pipe) 22 with an angled baffle plate 23 and a magnetic device 24 and a storage container 26, which can be arranged in a housing, not shown.

The dry mass 4.1 obtained from the reactor 0 is fed to the separator in the form of powder 4.2, which also contains the magnetic, phosphorus-containing compound 4.3. In particular, the powder is 4.2 in the optional crushing unit 20 for homogeneous mechanical grinding to powder 4.2. This makes sense if the coarser dry matter particles with a diameter > 100 μm have not been separated from the powder 4.2 beforehand or if the dry matter 4.1 is obtained from a process other than bioreactor 0, in which a sufficiently small particle size was not obtained. The comminution unit 20 can have a mechanical grinder, for example a cone grinder or a disc grinder or the like.

After grinding in the crushing unit 20, the entire mass, which is now largely homogeneous as a fine powder 4.2, falls through the funnel 21 below and then in free fall into the downpipe 22, where it hits the angled impact plate 23. Through the impact The powder 4.2 is swirled onto the baffle plate 23 to form a cloud of powder and then continues to fall in free fall along the inner drop pipe wall. In the middle of the downpipe 22, the magnetic device 24 is arranged from the outside, preferably in the form of electromagnets. When energized appropriately, the electromagnets generate a magnetic field 25 which acts in the interior of the downpipe. Due to the effective magnetic field 25, magnetic metal compounds of the phosphorus 4.3, for example iron phosphate, are magnetically attracted to the downpipe wall from the inside and are thus removed from the remaining non-magnetic powder 4.2. The powder 4.2 freed from magnetic metal compounds 4.3 continues to fall in free fall into the storage container 26 located below the downpipe 22 and settles there in the floor area.

An alternative process can be that the substances discharged from the bioreactor 0 are treated separately. The coarse dry matter particles with a diameter >100 μm can be ground up with the crushing unit 20 and then separated magnetically from the iron phosphate in the magnetic separator. The fine part from powder 4.2 with a diameter of <100 μm can be fed directly to the magnetic separator and separated magnetically from the iron phosphate.

It goes without saying that if the particle size of the dry mass is sufficiently small, an (additional) comminution process or the comminution unit 20 can be dispensed with.

Figure 6 shows the separator as previously described in Figure 5, but the storage container 26 has been set aside and the storage container 27 is now located under the downpipe 22 to accommodate the separated magnetic, phosphorus-containing compound (e.g. iron phosphate particles) 4.3 the electromagnet 24 generating the magnetic field 25 has been switched off, so that the magnetic metal compounds 4.3 fall in free fall into the storage container 27 and settle there in the floor area. Thus, the magnetic, phosphorus-containing compound (for example iron phosphate particles) 4.3 and the remaining dry mass 4.1 are received and collected separately from one another in the storage containers 27 and 26, respectively.

Reference List

0 grinding device / bioreactor

1 housing

1.1 soil

1.2 peripheral wall

1.3 Lid

2 mixers / auger

2.1 wings

3 wooden ball

4 Biogenic waste

4.1 Dry Matter

4.2 powdered dry matter / powder

4.3 magnetic phosphorus compound / iron phosphate particles

5 water inlet/supply line/supply line

6 drying medium inlet / air inlet and/or steam inlet / supply line /

supply line

6.1 Desiccant Inlet / Air Inlet and/or Steam Inlet / Feed Line / Feed Line

6.2 Desiccant Inlet / Air Inlet and/or Steam Inlet / Feed Line / Feed Line

6.3 Desiccant Inlet / Air Inlet and/or Steam Inlet / Feed Line / Feed Line

7 Desiccant outlet / discharge line / exhaust air and/or vapor discharge

8 discharge device

10 surface

20 grinding device / housing with crushing unit

21 Conical funnel

22 drop case / downspout with tapered end pieces

23 Angled baffle for nebulizing

24 magnetic device / electromagnet 25 magnetic field

26 Storage tank 27 Storage tank 30.1 Housing wall A axis

HiWax fill level

H Start level HNass level

H Dry level H Powder level

Claims

patent claims

1. Process for separating a magnetic, phosphorus-containing compound (4.3), in particular iron phosphate, from a dry mass (4.1), in particular from biogenic residues, by dry magnetic separation with the following steps: a) providing the dry mass (4.1) in the form of a powder (4.2) and b) applying a magnetic field (25) to the powder (4.2), so that the magnetic, phosphorus-containing compound (4.3) is attracted by the magnetic field (25) and separated from the powder (4.2).

2. The method according to claim 1, wherein in step b) the magnetic, phosphorus-containing compound (4.3) separated from the powder (4.2) is on a magnet (24) generating the magnetic field (25) or an element magnetized by the magnet (24). settles.

The method of claim 2, further comprising: c) switching off the magnetic field (25) so that the magnetic phosphorus-containing compound (4.3) deposited on the magnet (24) or magnetized element is released.

4. The method according to any one of the preceding claims, wherein the powder (4.2) is subjected to the magnetic field (25) by the powder (4.2) being moved through the magnetic field (25) or being guided by gravity through the magnetic field (25).

5. The method according to claim 4, wherein the powder (4.2) moves under the force of gravity through a drop casing and is deposited on an inner wall of the drop casing which is magnetized from the outside by the magnet (24).

6. The method according to any one of the preceding claims, wherein the powder (4.2) has a maximum particle size of 100 μm.

7. The method according to any one of the preceding claims, wherein the provision of the dry matter (4.1) in the form of a powder (4.2) comprises grinding the dry matter (4.1).

8. The method according to claim 7, wherein the grinding of the dry mass (4.1) takes place with the aid of balls (3), in particular wooden balls, set in motion.

9. The method according to claim 8, wherein the grinding of the dry matter (4.1.) is carried out with simultaneous drying of the dry matter (4.1).

10. The method according to any one of the preceding claims, wherein the powder (4.2) has a dry residue content of at least 90% by weight.

11. Plant for separating a magnetic, phosphorus-containing compound (4.3), in particular iron phosphate, from a dry mass (4.1), in particular from biogenic residues, comprising a grinding device (0, 20) for grinding the dry mass (4.1) into a powder (4.2) , a separating device (40), comprising at least one magnet (24) for generating a magnetic field (25), wherein the separating device (40) is designed to apply the magnetic field to the powder (4.2), so that the magnetic, phosphorus-containing compound ( 4.3) is attracted by the magnetic field and separated from the powder (4.2).

12. Plant according to claim 11, wherein the grinding device (0, 20) comprises a mixer equipped with balls (3), in particular wooden balls.

13. Plant according to one of claims 11 to 12, wherein the separating device (40) has a case housing (22) which is open at the top and bottom and has at least one closed peripheral wall, the magnet (24) being arranged outside the peripheral wall so that it has a of the case (22) acting magnetic field (25) is able to generate.

14. Plant according to one of claims 11 to 13, wherein the separating device (40) comprises a swirling device (23) for swirling the powder (4.2), which is in particular designed to swirl the powder (4.2) in the magnetic field (25).

15. Installation according to one of claims 11 to 14, wherein the magnet (24) is an electromagnet or a permanent magnet.