AT528133A4 - Process for separating elemental phosphorus from phosphate-containing starting materials - Google Patents

Abstract

A method for separating elemental phosphorus from phosphate-containing starting materials, in particular from phosphate-containing waste materials such as sewage sludge, comprises at least the following steps: providing at least one phosphate-containing starting material together with free carbon, incomplete combustion of the free carbon together with the phosphate-containing starting material in a carbon excess compared to combustion oxygen, collecting a melt (11) of the dephosphorized starting material, withdrawing elemental phosphorus and carbon monoxide formed during incomplete combustion with the gas phase, and separating elemental phosphorus from the gas phase.

Description

procedure.

The prices for rock phosphate have recently experienced a steady increase due to the scarcity of suitable raw material sources. Furthermore, the mined phosphate ores increasingly contain significant amounts of uranium, cadmium, selenium, and other harmful substances. Such impurities can only be removed with great effort, so the use of phosphates from such sources

contaminated ores is becoming increasingly uneconomical.

On the other hand, waste materials sometimes contain relatively high levels of phosphorus compounds. This applies, for example, to sewage sludge, animal meal, bone meal, and also

steel mill slag and the like.

High-purity phosphorus starting materials, which can be produced from elemental phosphorus (P, white phosphorus), are required, particularly for food production and the pharmaceutical industry, but also for other areas of technology such as electromobility, crop protection products, flame retardants, the production of lubricants, catalysis, and electronic applications. However, their production is becoming increasingly difficult and

at least in Europe it is no longer carried out.

A major problem in the extraction of elemental phosphorus from the starting materials of the type mentioned above, in particular from waste materials such as sewage sludge, animal meal,

Bone meal and/or steel mill slag and/or materials such as

volatile and highly toxic, pose a major problem.

The present invention is therefore based on the object of creating a process and a corresponding device that enable the extraction of elemental phosphorus from phosphate-containing waste materials such as sewage sludge and the like without the formation of phosphorus sludge or phosphines. At the same time, the formation of undesirable iron-phosphorus alloys such as iron phosphides, ferrophosphate, and Fe»P, as well as CO2 emissions, are to be avoided compared to prior art processes.

become.

To achieve this object, the method mentioned at the outset comprises at least the following steps:

Providing at least one phosphate-containing starting material together with free carbon,

incomplete combustion of free carbon together with the phosphate-containing starting material in the case of a carbon surplus compared to combustion oxygen,

Collecting a melt of the dephosphorized starting material,

Removal of residues formed during incomplete combustion

elemental phosphorus and carbon monoxide with the gas phase, and

The process according to the invention is therefore based on the idea of subjecting the phosphate-containing starting materials, in particular sewage sludge and/or bone meal, together with free carbon, i.e., elemental carbon, to an incomplete combustion process. Within the context of the present invention, an incomplete combustion process or incomplete combustion is understood to mean an exothermic gasification or carbonization process. Combustion oxygen is supplied to such a process to an extent that does not lead to the complete oxidation of the carbon provided by the phosphate-containing starting material. In other words, the incomplete combustion of the free carbon together with the starting material is carried out in a carbon surplus compared to combustion oxygen. In this way, the carbon only burns or carbonizes down to carbon monoxide, so that virtually no carbon dioxide is emitted in the process according to the invention. The incomplete combustion step results in a melt of the dephosphorus-removed starting material, which is collected and appropriately further processed, utilized, and/or disposed of. The phosphates contained in the starting material are reduced during combustion, so that they pass into the gas phase of the process formed during combustion as elemental phosphorus and can be removed with the gas phase. Carbon monoxide is also removed with the gas phase and appropriately treated. Finally, the elemental phosphorus is separated from the gas phase and utilized. The process according to the invention thus allows phosphate-containing starting materials to be used for the recovery of elemental phosphorus even with relatively low phosphate contents.

to use phosphorus.

Carbon dioxide is oxidized.

Depending on whether the phosphate-containing starting material contains carbon or not, the step of providing the phosphate-containing starting material according to a preferred embodiment of the present invention is carried out together with the free carbon by pyrolysis of dried organic and phosphate-containing starting material, wherein a carbon carrier can optionally be added, and/or by pyrolysis of incinerated phosphate-containing starting material, which necessarily takes place together with at least one added carbon carrier. In other words, a phosphate-containing starting material of the organics, i.e., contains organic substances and thus carbon, can be provided by pyrolysis for the process according to the invention, whereas a phosphate-containing starting material that has been incinerated, as is the case with sewage sludge ash, and thus no longer contains any carbon, must have a carbon carrier added to it in order to

Carbon For subsequent incomplete burning in the form

or to increase.

Wood, preferably waste wood or damaged wood and/or plastic, preferably waste plastic, can be used as an added carbon carrier, as is the case with a preferred

embodiment of the present invention.

According to a preferred embodiment of the present invention, the process can be conducted in such a way that heat generated during incomplete combustion of the gas phase and/or the melt is fed to the step of providing the phosphate-containing starting material together with the free carbon, in particular to a pyrolysis of a phosphate-containing starting material together with a carbon carrier. During the incomplete combustion process step, large amounts of heat naturally arise, which can be used in an energetically favorable manner for drying, preheating, and preferably also for pyrolyzing the starting materials.

can be used.

Likewise, in a preferred and particularly advantageous manner, the pyrolysis gas formed during pyrolysis can be fed into a combustion chamber to generate heat for the pyrolysis. This creates a largely closed process in terms of energy, in which the relatively high heat requirement for drying and, in particular, pyrolysis during preparation of the starting materials can be largely recovered from the subsequent partial combustion. In addition to methane, the gas fractions also contain unsaturated and saturated

Hydrocarbon compounds, including aliphatics and aromatics,

even strict environmental requirements can be met.

As mentioned at the beginning, the phosphate-containing starting materials may contain, in addition to the organic components, toxic substances, particularly heavy metal fractions and alkali compounds. In order to degrade these harmful accompanying substances as far as possible during the partial combustion process step, the process according to the invention can advantageously be further developed in such a way that steelworks dust is added to the pyrolysis starting materials. Electric furnace dusts from special steel and stainless steel production, which contain, among other things, catalytically active amounts of zinc, chromium, and nickel, can be used as steelworks dust. The catalytic effect of these dusts leads to a degradation of organic substances in the gas phase, so that the gas stream generated during the process can be easily dedusted and thus detoxified by conventional filter systems. The catalytic effect of the steelworks dusts also extends to the gasification process during the incomplete combustion of the phosphate-containing starting materials, so that the reaction kinetics are directed towards carbon monoxide and elemental phosphorus in the sense of

invention is favored.

According to a preferred embodiment of the present invention

Pyrolysis oil formed during pyrolysis can be hydrogenated to

synthetic fuel. This requires

valuable fuels and combustibles can be obtained.

Preferably, the melt of the dephosphorus-removed starting material is collected as a melt of an iron alloy covered with a pozzolan melt. The two phases of this melt can be recycled or disposed of differently. For example, the pozzolan melt can be further processed into insulating wool. A corresponding device for this purpose is available, for example, in

the publication WO 98/45215 A2.

The pozzolan formed in the process according to the invention can alternatively also be processed to obtain a cement component if the pozzolan is rapidly cooled and thus vitrified. In this context, it can be advantageous if animal meal and/or bone meal are mixed into the starting material, for example the sewage sludge, before pyrolysis, as is the case in a preferred embodiment of the present invention. This increases the calcium content of the mixture and thus the hydraulicity of the resulting cement component. In addition, animal meal or bone meal has a particularly high phosphate content as well as a significant organic fraction. In this way, phosphates from animal meal and bone meal are also used as elemental phosphorus using the process according to the invention.

These organic substances in turn lead to a

of fuels and combustibles.

According to a preferred embodiment of the present invention, the process according to the invention is carried out such that the step of incomplete combustion of the free carbon together with the phosphate-containing starting material takes place, firstly, in the entrained stream in a riser pipe and secondly, in a refractory bed connected to the riser pipe with the interposition of a cyclone separator, wherein elemental phosphorus and carbon monoxide are removed from the cyclone separator and downstream of the refractory bed. In the riser pipe, the pyrolysis coke is exothermically gasified to carbon monoxide using oxygen, i.e., partially or incompletely combusted. The temperature is preferably set such that the temperature at the cyclone separator is a maximum of 850°C, thereby avoiding packing of the gasification material at the riser pipe and/or cyclone separator. To regulate the temperature, a hydrogen-free carbon carrier can additionally be added with stoichiometric oxygen addition. In this way, an optimal temperature window with a suitable carbon monoxide partial pressure can be set for the reduction processes. An indirect reduction of the phosphorus and iron oxide components already takes place in the riser tube. This produces metallic iron and gaseous, elemental phosphorus (P»>), with the iron being solid and dusty. This hot dust/gas mixture is injected directly into the refractory bed.

The elemental phosphorus already produced in the riser pipe is

However, before entering the refractory bed,

to prevent the formation of iron phosphides in the refractory bed

Phosphorus would occur.

The further addition of oxygen causes the temperature in the refractory bed to rise to a maximum of 1500 °C, whereby the residual carbon in the mixture is gasified to carbon monoxide. The dust is thereby melted, and a two-phase melt can be collected. The collected melt consists, as described above, of an iron alloy covered with a pozzolan melt. The iron alloy contains particularly phosphorus and copper and also collects all siderophilic heavy metals. The atmospheric heavy metal species pass into the gas phase, whereby the relatively high zinc content of the feedstock used, in particular sewage sludge, leads to residual desulphurisation through the formation of zinc sulphide in the refractory bed or a combustion device such as a cyclone separator downstream of the

Brenner leads.

In the process according to the invention, the refractory bed is arranged in a tubular reactor that functions as a cocurrent shaft furnace, with an upper layer of the refractory bed consisting of high-clay refractory particles and a lower layer of the refractory bed arranged underneath, preferably consisting of coarse-grained coke and/or graphite. At the lower end of the refractory bed, a collection area for the melt is formed in the form of a sump, in which the separation of the two melt phases into the iron alloy layer and the pozzolana layer takes place. At this point, the melt can

In addition, the drainage area or the sump is also used

the hot gas from incomplete combustion is removed, which

Hot gas according to the invention carbon monoxide and elemental phosphorus (P>»)

as well as the atmospheric heavy metal compounds of the transition group elements. The approximately 1500 °C hot gas is cooled to approximately 600 °C by means of a heat exchanger and separated from the volatile heavy metal species by means of a hot gas filter. The product gas is then further cooled to approximately 150 °C, during which P is converted to P, which can be condensed by water injection. Carbon monoxide and water vapor are removed from the system and can be further converted to synthesis gas. As already mentioned, the hot air obtained here, with a temperature of approximately 1400 °C, can be used to heat the pyrolysis. In addition, this excess heat can also be used for pre-drying, for example, mechanically dewatered

Sewage sludge can be used as a phosphate-containing feedstock.

In the process according to the invention, the supply of combustion oxygen is preferably carried out in such a way that combustion oxygen is introduced into the riser pipe and/or after the

cyclone separator.

In order to prevent a backflow of reaction and product gases from occurring due to the oxygen supply into the riser pipe and/or the cyclone separator, the process according to the invention can advantageously be further developed such that the pressure loss from the gas outlet of the cyclone separator and/or the pressure loss between the cyclone separator and the refractory bed is adjusted in a controlled manner. In this way, it can be ensured that, despite the injection of gas containing combustion oxygen into the riser pipe or into a vortex chamber formed downstream of the cyclone separator, the pressure conditions can be controlled such that a backflow of gas containing combustion oxygen and/or a backflow of product gas into the riser pipe is not possible.

occurs.

According to an alternative process, the invention can advantageously be further developed in such a way that the phosphate-containing starting material is pre-reduced in the entrained stream in a riser pipe and is blown into a burner for incomplete combustion, which is connected to the riser pipe with the interposition of a cyclone separator, whereby elemental phosphorus and carbon monoxide are extracted from the burner as burner hot gas. The burner here represents an alternative to the previously described reduction

of the phosphates in the refractory fill.

Naturally, hot gas containing elemental phosphorus and carbon monoxide is also produced in the burner, whereby the process according to the invention can preferably be further developed in such a way that the burner hot gas is fed into the riser pipe for pre-reduction of the phosphate-containing starting material. Unlike the previously described process with a riser pipe and a refractory bed, in which oxygen is fed into the riser pipe, in this process no oxygen is added to the riser pipe, so that only a pre-reduction of the phosphates takes place. The direct contact of the burner hot gas with the starting material, however, leads to a strong heating of the starting material, so that the reduction of the phosphates in the burner subsequently takes place after the addition of oxygen in a kinetically favorable manner.

very quickly and completely.

According to a preferred embodiment of the present invention, the phosphate-containing feedstock is metered into the riser via a secondary cyclone separator, to which the phosphate-containing feedstock is fed via the gas outlet of the cyclone separator between the riser and the burner. This also results in the phosphate-containing feedstock being preheated and fluidized, so that it is already in the riser with

a large specific surface area, so that

if necessary, complete drying and pre-reduction

be favored.

According to a preferred embodiment of the present invention, the process according to the invention is carried out such that elemental phosphorus and carbon monoxide are removed from the secondary cyclone separator. In the secondary cyclone separator, elemental phosphorus and carbon monoxide are reacted in the gas phase after incomplete combustion in the burner and, if applicable, passing through the riser pipe and the primary cyclone separator, which is arranged between the riser pipe and the burner. By using a primary cyclone separator and a secondary cyclone separator, even larger quantities of hot gas from the burner can be reliably separated from any not yet reduced and therefore still solid phosphates. Any unreacted phosphates form an aerosol as solid dust and are separated from the gas phase in the cyclone separator and conveyed into the riser pipe. This ensures that the phosphates are fully converted, even if this requires repeated passage through the riser pipe and the burner.

should require.

The device according to the invention for carrying out the method according to the invention comprises at least one combustion device, in particular a refractory bed or a burner, connected to a riser pipe with the interposition of a cyclone separator, wherein the riser pipe can be fed with a phosphate-containing starting material in the entrained flow and the combustion device has a collecting container for collecting a melt of the dephosphorized starting material as well as an extraction device for elemental phosphorus and carbon monoxide. The significance and advantages of the above-mentioned

Device elements have already been described in the description of the

The method according to the invention is discussed below. Thus, two device variants are conceivable according to the invention, which, however, have in common a riser pipe and a combustion device, with a primary cyclone separator arranged between them. As described above, a refractory bed or a burner is used as the combustion device in which the most complete reduction of the phosphates takes place within the scope of the present invention.

conceivable.

In both device variants, it can preferably be provided that the combustion device is connected to the cyclone separator with the interposition of a vortex chamber for blowing in combustion oxygen. Such a vortex chamber, into which combustion oxygen is blown, ensures optimal fluidization of the phosphate-containing starting material, thereby optimally increasing the specific surface area of the starting materials, so that the reaction kinetics and the completeness of the reduction of the

Phosphates to elemental phosphorus is favored.

In order to prevent a backflow of the reaction and product gases from occurring due to the oxygen supply into the vortex chamber, the device according to the invention can be further developed in such a way that a physical or gas-dynamic and preferably controllable blocking device is arranged between the vortex chamber and the cyclone separator and/or at the gas outlet of the cyclone separator

is arranged.

Preferably, a secondary cyclone separator, separate from the cyclone separator arranged between the riser pipe and the combustion device, is designed as an extraction device for elemental phosphorus and carbon monoxide. In the case of the device variant with a burner, this can be advantageous.

to reliably separate large quantities of hot gas from the solids

In this variant of the invention, the hot gas is first led through the riser pipe into the primary cyclone separator between the riser pipe and the burner, where the phosphate-containing starting materials are separated from the hot gas, so that the phosphate-containing starting materials are conveyed via the vortex chamber into the

burner.

According to a preferred embodiment of the present invention, the gas outlet of the cyclone separator is fed to the secondary cyclone separator between the riser pipe and the combustion device. In this way, the phosphate-containing starting materials can be fed to the gas outlet of the primary cyclone separator between the riser pipe and the burner, so that they are already fluidized there by the hot gas. The phosphate-containing starting materials then pass through the secondary cyclone separator and from there into the riser pipe, where they are again fluidized by the hot gas stream from the burner and conveyed to the primary cyclone separator. The hot gas passes through the primary cyclone separator between the riser pipe and the burner and then enters the secondary cyclone separator and subsequently into the riser pipe.

a.

The invention will be explained in more detail below with reference to an embodiment shown in the drawing. Figure 1 shows a schematic representation of a variant of the method according to the invention, Figure 2 shows a detail of a first device variant for carrying out the method, and Figure 3 shows a schematic representation of a device for carrying out

a second process variant of the process according to the invention.

In Figure 1, a combustion device of an apparatus according to the invention for carrying out the method according to the invention is designated by the reference numeral 1. In the combustion device 1

partial combustion or exothermic gasification

of the phosphate-containing starting materials, whereby according to the variant of Figure 1 this already takes place in part in the riser pipe 2. The riser pipe 2 can be

Combustion oxygen must be supplied.

Reference numeral 3 designates a pyrolysis reactor, to which sewage sludge or sewage sludge ash as phosphate-containing starting material and, if appropriate, wood or plastic as carbon carrier are fed at position 4. The pyrolysis reactor 3 is fired by a combustion chamber 5, from which pyrolysis gas can be extracted at position 6 and pyrolysis oil at position 7. The exhaust gas of the pyrolysis reactor 3 is extracted at position 8. In the example shown in Figure 1, the pyrolysis gas is fed to the combustion chamber 5. After pyrolysis in the pyrolysis reactor 3, hot grinding of pyrolysis coke formed in the reactor 3 takes place in a grinding device 9. The ground pyrolysis

Coke is fed into the riser pipe 2.

After, as already mentioned, the reduction of the phosphates to elemental phosphorus (P»>) and the oxidation of the free carbon to carbon monoxide (CO) has taken place in the riser 2 and in the combustion device 1, these gaseous process products can be withdrawn from the extraction device 10. The melt 11 collects in the sump 12 at the lower end of the refractory bed 13 and forms a layer 11a of a phosphate-containing iron alloy, which is covered by a pozzolana layer 11b. The pozzolana and the iron alloy

can be tapped from the swamp 12.

The approximately 1500 °C hot gaseous process products P> and carbon monoxide are subsequently cooled to about 600 °C in a heat exchanger 14, filtered in a hot gas filter 15 and cooled to about 150 °C in a further heat exchanger 16 and in the

Follow in a splash condenser 17 to a Pı - melt 18 with

a temperature of approximately 50 °C. The melt 18 can be tapped at position 19, and carbon monoxide and water are removed at position 20. Reference numeral 21 denotes a cooling water supply. Cooling air is supplied to the heat exchangers 14 and 16 in the direction of arrows 22 in countercurrent, which subsequently heats up to 1400 °C and is discharged as hot blast of the

Combustion chamber 5 can be fed to pyrolysis.

In Figure 2, identical parts are provided with identical reference numerals where possible, and it can be seen that the riser pipe 2 is connected via a cyclone separator 23 to a combustion device 1 in the form of a refractory bed 13. Reference numeral 24 denotes adjustable, regulated blocking devices, via which the pressure loss through the gas outlet 25 of the cyclone separator 23 and through the vortex chamber 25 can be adjusted. A heat exchanger is provided with the reference numeral 27, and the gas outlet through the gas outlet 25 is effected by a controlled induced draft 28. As already described in connection with Figure 1, the product gas is again fed to a splash condenser 17 for condensation of P» to Pı. Reference numeral 29 denotes an axially displaceable suction pipe of the cyclone separator 23, with which the separation performance of the

cyclone separator can be adjusted.

Figure 3 schematically shows a riser pipe 2, which is fed to a primary cyclone separator 23 between the riser pipe 2 and the combustion device 1. The combustion device 1l is designed in the form of a burner 30, to which the phosphorus-containing starting material is fed via a lance 31. For this purpose, a rotary valve 32 is also provided, which

The starting material in turn comes from the primary cyclone separator 23.

The pyrolysis coke is fed to the device according to Figure 3 at the

Position 33 is fed to the gas outlet of the cyclone separator 23, where

This is fluidized by the hot gas from the burner 30 and fed to a secondary cyclone separator 34. The dust fraction containing the phosphates is led via line 35 to the riser 2, where it is conveyed upwards by the hot product gas from the burner 30, where it is pre-reduced. The phosphate-containing starting material, thus pre-treated, then passes into the cyclone separator 23 and from there into the rotary valve 32 and the burner 30 for complete reduction to elemental phosphorus and carbon monoxide. The melt is then collected in an extraction device 11 and extracted in phase separation. Gaseous elemental phosphorus and carbon monoxide are extracted through the gas outlet 36 of the secondary cyclone separator 34, for which an induced draft fan 28 is provided. The gas processing and separation of elemental phosphorus (Pı) at position 37 and carbon monoxide at position 38 is shown schematically in Figure 3 with

Visiting hours 39.

Patent claims:

1. A process for separating elemental phosphorus from phosphate-containing starting materials, in particular from phosphate-containing waste materials such as sewage sludge, comprising at least the following steps:

Providing at least one phosphate-containing starting material together with free carbon,

incomplete combustion of free carbon together with the phosphate-containing starting material in the case of a carbon surplus compared to combustion oxygen,

Collecting a melt (11) of the dephosphorized starting material,

Removal of elemental phosphorus and carbon monoxide formed during incomplete combustion with the gas phase, and

Separation of elemental phosphorus from the gas phase.

2. Process according to claim 1, characterized in that the carbon excess compared to the combustion oxygen in the step of incomplete combustion is determined by a molar ratio of carbon (C) to combustion oxygen (OO) of 2:1 to 8:1, preferably of 3:1 to 7:1, further preferably of 4:1

to 6:1 and particularly preferably 5:1.

3. A method according to claim 1 or 2, characterized in that the step of providing the phosphate-containing starting material together with the free carbon is carried out by pyrolysis of dried organic and phosphate-containing starting material, preferably together with at least one added carbon carrier and/or by pyrolysis of incinerated phosphate-containing starting material together with at least one added

Carbon carrier.

4. A method according to claim 3, characterized in that wood, preferably waste wood or damaged wood and/or plastic, preferably

Waste plastic is used.

5. Method according to one of claims 1 to 4, characterized in that heat of the gas phase and/or the melt formed during incomplete combustion is supplied to the step of providing the phosphate-containing starting material together with the free carbon, in particular a pyrolysis of a phosphate-containing starting material together with a

Carbon carrier.

6. Method according to one of claims 3 to 5, characterized in that pyrolysis gas formed during the pyrolysis is fed to a combustion chamber (5) to generate heat for the pyrolysis

becomes.

7. A process according to any one of claims 3 to 6, characterized in that the starting materials of the pyrolysis

Steel mill dust is added.

7. A process according to any one of claims 3 to 6, characterized in that pyrolysis oil formed during the pyrolysis is

Hydrogenation is refined into synthetic fuel.

8. A process according to any one of claims 1 to 7, characterized in that the carbon monoxide withdrawn with the gas phase is converted to carbon dioxide and hydrogen, preferably by

a water gas shift reaction.

9, Method according to one of claims 1 to 8, characterized

characterized in that the melt (11) of the dephosphorized

starting material as a layered with a pozzolan melt (11b)

melt (1la) of an iron alloy is collected.

10. A method according to any one of claims 1 to 9, characterized in that the step of incomplete combustion of the free carbon together with the phosphate-containing starting material is carried out to a first extent in the entrained stream in a riser pipe (2) and to a second extent in a refractory bed (13) which is connected to the riser pipe (2) with the interposition of a cyclone separator (23), wherein elemental phosphorus and carbon monoxide are removed from the cyclone separator (23) and after the

Refractory fill (13) must be removed.

11. Method according to claim 10, characterized in that combustion oxygen is introduced into the riser pipe (2) and/or after the

Cyclone separator (23).

12. Method according to claim 10 or 11, characterized in that the pressure loss from the gas outlet (25) of the cyclone separator (23) and/or the pressure loss between the cyclone separator (23)

and the refractory fill (13) is adjusted in a controlled manner.

13. A method according to any one of claims 1 to 9, characterized in that the phosphate-containing starting material is pre-reduced in the entrained stream in a riser pipe (2) and is blown into a burner (30) for incomplete combustion, which is connected to the riser pipe (2) with the interposition of a cyclone separator (23), wherein elemental phosphorus and carbon monoxide are withdrawn from the burner (30) as burner hot gas.

14. Method according to claim 13, characterized in that the

Burner hot gas for pre-reduction of the phosphate-containing

starting material is fed into the riser pipe (2).

211

15. The method according to claim 12 or 13, characterized in that the phosphate-containing starting material is metered into the riser pipe (2) via a secondary cyclone separator (34), to which the phosphate-containing starting material is fed via the gas outlet (25) of the cyclone separator (23) between the riser pipe (2) and the burner

(30).

16. A process according to claim 15, characterized in that elemental phosphorus and carbon monoxide are recovered from the secondary

Cyclone separator (34) can be removed.

17. Device for carrying out the method according to one of claims 1 to 16, comprising at least one combustion device (1), in particular a refractory bed (13) or a burner (30), connected to a riser pipe (2) with the interposition of a cyclone separator (23), wherein the riser pipe (2) can be fed with a phosphate-containing starting material in the entrained flow and the combustion device (1) has a collecting container for collecting a melt (11) of the dephosphorized starting material and a discharge device (10) for elemental

phosphorus and carbon monoxide.

18. Device according to claim 17, characterized in that the combustion device (1) with the interposition of a swirl chamber for blowing combustion oxygen to the

Cyclone separator (23) is connected.

19. Device according to claim 18, characterized in that a physical or gas-dynamic and preferably controllable blocking device (24) is arranged between the vortex chamber and the cyclone separator (23) and/or at the gas outlet (25) of the cyclone separator (23).

20. Device according to one of claims 17 to 19, characterized in that a secondary cyclone separator (34) different from the cyclone separator (23) arranged between the riser pipe (2) and the combustion device (1) serves as an extraction device for elemental phosphorus and carbon monoxide

is trained.

21. Device according to claim 20, characterized in that the gas outlet (25) of the cyclone separator (23) between the riser pipe (2) and the combustion device (1) is connected to the secondary

Cyclone separator (34).

Claims (21)

Patent claims: 1. A process for separating elemental phosphorus from phosphate-containing starting materials, in particular from phosphate-containing waste materials such as sewage sludge, comprising at least the following steps: Providing at least one phosphate-containing starting material together with free carbon, incomplete combustion of free carbon together with the phosphate-containing starting material in the case of a carbon surplus compared to combustion oxygen, Collecting a melt (11) of the dephosphorized starting material, Removal of elemental phosphorus and carbon monoxide formed during incomplete combustion with the gas phase, and Separating elemental phosphorus from the gas phase, characterized in that the carbon excess compared to the combustion oxygen in the step of incomplete combustion is determined by a molar ratio of carbon (C) to combustion oxygen (O,) of 2:1 to 8:1, preferably of 3:1 to 7:1, further preferably of 4:1 to 6:1 and particularly preferably of 5:1. 2. Process according to claim 1, characterized in that the step of providing the phosphate-containing starting material together with the free carbon is carried out by pyrolysis of dried organic and phosphate-containing starting material, preferably together with at least one added carbon carrier and/or by pyrolysis of incinerated phosphate-containing starting material together with at least one added Carbon carrier. 3. Method according to claim 2, characterized in that added carbon carrier wood, preferably waste wood 27/31 [ MOST RECENT CLAIMS | or damaged wood and/or plastic, preferably Waste plastic is used. 4. Method according to one of claims 1 to 3, characterized in that heat of the gas phase and/or the melt formed during incomplete combustion is supplied to the step of providing the phosphate-containing starting material together with the free carbon, in particular a pyrolysis of a phosphate-containing starting material together with a Carbon carrier. 5. Method according to one of claims 2 to 4, characterized in that pyrolysis gas formed during the pyrolysis is fed to a combustion chamber (5) to generate heat for the pyrolysis becomes. 6. A process according to any one of claims 2 to 6, characterized in that the starting materials of the pyrolysis Steel mill dust is added. 7. A process according to any one of claims 2 to 6, characterized in that pyrolysis oil formed during the pyrolysis is Hydrogenation is refined into synthetic fuel. 8. A process according to any one of claims 1 to 7, characterized in that the carbon monoxide withdrawn with the gas phase is converted to carbon dioxide and hydrogen, preferably by a water gas shift reaction. 9, Method according to one of claims 1 to 8, characterized in that the melt (11) of the dephosphorized starting material is coated with a pozzolan melt (11b) melt (1la) of an iron alloy is collected. 28/31 | MOST RECENT CLAIMS | 10. A method according to any one of claims 1 to 9, characterized in that the step of incomplete combustion of the free carbon together with the phosphate-containing starting material is carried out to a first extent in the entrained stream in a riser pipe (2) and to a second extent in a refractory bed (13) which is connected to the riser pipe (2) with the interposition of a cyclone separator (23), wherein elemental phosphorus and carbon monoxide are removed from the cyclone separator (23) and after the Refractory fill (13) must be removed. 11. Method according to claim 10, characterized in that combustion oxygen is introduced into the riser pipe (2) and/or after the Cyclone separator (23). 12. Method according to claim 10 or 11, characterized in that the pressure loss from the gas outlet (25) of the cyclone separator (23) and/or the pressure loss between the cyclone separator (23) and the refractory fill (13) is adjusted in a controlled manner. 13. A method according to any one of claims 1 to 9, characterized in that the phosphate-containing starting material is pre-reduced in the entrained stream in a riser pipe (2) and is blown into a burner (30) for incomplete combustion, which is connected to the riser pipe (2) with the interposition of a cyclone separator (23), wherein elemental phosphorus and carbon monoxide are withdrawn from the burner (30) as burner hot gas. become. 14. A method according to claim 13, characterized in that the burner hot gas is used for pre-reducing the phosphate-containing starting material is fed into the riser pipe (2). 15. Method according to claim 12 or 13, characterized in that that the phosphate-containing starting material is transported via a secondary 29/31 [ MOST RECENT CLAIMS | Cyclone separator (34) is dosed into the riser pipe (2), to which the phosphate-containing starting material is fed via the gas outlet (25) of the cyclone separator (23) between the riser pipe (2) and the burner (30). 16. A process according to claim 15, characterized in that elemental phosphorus and carbon monoxide are recovered from the secondary Cyclone separator (34) can be removed. 17. Device for carrying out the method according to one of claims 1 to 16, comprising at least one combustion device (1), in particular a refractory bed (13) or a burner (30), connected to a riser pipe (2) with the interposition of a cyclone separator (23), wherein the riser pipe (2) can be fed with a phosphate-containing starting material in the entrained flow and the combustion device (1) has a collecting container for collecting a melt (11) of the dephosphorized starting material and a discharge device (10) for elemental phosphorus and carbon monoxide. 18. Device according to claim 17, characterized in that the combustion device (1) with the interposition of a swirl chamber for blowing combustion oxygen to the Cyclone separator (23) is connected. 19. Device according to claim 18, characterized in that a physical or gas-dynamic and preferably controllable blocking device (24) is arranged between the vortex chamber and the cyclone separator (23) and/or at the gas outlet (25) of the cyclone separator (23). 20. Device according to one of claims 17 to 19, characterized in that a pressure drop formed between the riser pipe (2) and the Cyclone separator (23) arranged in the combustion device (1) 301 [ MOST RECENT CLAIMS | various secondary cyclone separators (34) as extraction devices for elemental phosphorus and carbon monoxide is trained. 21. Device according to claim 20, characterized in that the gas outlet (25) of the cyclone separator (23) between the riser pipe (2) and the combustion device (1) is connected to the secondary Cyclone separator (34). 31/31 | Most Recent Claims |