Process for producing phosphorus-chlorine compounds from phosphorus-oxygen compound-containing materials

Abstract

The present invention relates to a process for producing phosphorus-chloride compounds, characterized by the following steps: i. reacting a phosphorus-oxygen compound-containing material in the presence of tetrachloroethene at a temperature of 500 to 1000°C, and ii. removing and isolating the resulting phosphorus-chloride compound, particularly phosphorus oxychloride, from the exhaust gas stream.

Description

Technical Field

[0001] The present invention relates to a process for converting a phosphorus-oxygen compound-containing material into at least one phosphorus-chlorine compound. These can then be used for industrial applications.

Background Art

[0002] The decomposition of mainly water-insoluble phosphates plays an important role in analytical chemistry and technology, aiming to make the contained phosphorus compounds industrially and economically available in their form or to measure them quantitatively. In analytical chemistry, it is used for measuring phosphorus in rocks or ores. To obtain water-soluble phosphoric acid, which is mainly used as a fertilizer or detergent additive and secondarily as an acidifying agent in, for example, the food industry, a large amount of calcium phosphate source is reacted with sulfuric acid industrially.

[0003] Phosphate / phosphoric acid is industrially obtained by lowering the pH in a water slurry of ground phosphate ore, preferably using a mineral acid such as sulfuric acid or phosphoric acid, and then filtering. This process has the disadvantages of requiring a very large amount of acid, accompanying corresponding by-products that are difficult to control industrially, and absolutely requiring a filtration step. Therefore, a large amount of waste is also generated.

[0004] However, in these reactions, the desired phosphorus-chlorine compound cannot be obtained.

[0005] Phosphorus-chlorine compounds are prepared on an industrial scale only via an energy-intensive and complicated indirect route through the synthesis of elemental phosphorus and subsequent reaction with elemental chlorine.

[0006] The production of phosphorus-chloride compounds on an industrial scale generally follows this route: elemental phosphorus is produced from phosphate rock, coal, and mixtures in an electric arc furnace, and then the phosphorus is burned with chlorine to produce phosphorus-chloride compounds. The problems here are the extremely high energy consumption, high temperatures, handling of toxic white phosphorus, handling of contained arsenic compounds and toxic chlorine, the enormous amount of slag that needs to be disposed of, and very high CO2 emissions.

[0007] However, this method only yields phosphorus chloride such as PCl3. Phosphorus oxychloride (POCl3) cannot be obtained using this method and must be produced only through a further process involving oxidation from PCl3.

[0008] The process for directly obtaining phosphorus-chlorine compounds as volatile compounds from phosphates involves the use of carbon tetrachloride combined with an inert gas such as chlorine and / or carbon dioxide, as needed. This involves heating the sample to 700°C–900°C and passing a gas stream over it. The gas stream is then led to a scrubber where the phosphate is investigated. Quantitative conversions have been reported, and this process has been tested with numerous metal phosphates (Non-Patent Literature 1 and Non-Patent Literature 2). [Prior art documents] [Non-patent literature]

[0009] [Non-Patent Document 1] Jannasch, P., Jilke, W.; Journal fuer praktische Chemie (Journal for Practical Chemistry), 21, 1908 [Non-Patent Document 2] Jannasch P.,Jilke,W.;Journal fuer praktische Chemie,113,1909 [Overview of the project] [Problems that the invention aims to solve]

[0010] The long reaction time described is a drawback of this process. However, above all, the use of carbon tetrachloride in industrial processes was subsequently banned because it depletes the ozone layer. Therefore, this reaction cannot be carried out industrially. [Means for solving the problem]

[0011] the purpose Therefore, the object of the present invention is to discover a process for producing phosphorus-chlorine compounds that does not have the drawbacks of the prior art described above. Surprisingly, i. In the presence of tetrachloroethene, the phosphorus-oxygen compound-containing material is reacted at a temperature of 500°C to 1000°C, preferably 600°C to 900°C, and particularly 700°C to 850°C. ii. Deriv the generated phosphorus-chlorine compounds, particularly phosphorus oxychloride, into the exhaust gas stream and isolate them. A process for producing phosphorus-chlorine compounds, particularly phosphorus oxychloride, characterized by the above, has been discovered.

[0012] Preferably, phosphorus oxychloride, which is a phosphorus-chlorine compound, is produced by the process of the present invention. [Modes for carrying out the invention]

[0013] Phosphorus-oxygen compounds Various phosphorus-oxygen compound-containing materials may be used. For example, a phosphorus-oxygen compound-containing material may contain at least one phosphorus-oxygen compound selected from the group consisting of inorganic alkali metal and / or alkaline earth metal salts of phosphorus-oxygen compounds, their phosphates, especially calcium phosphate, apatite, especially chloroapatite or hydroxylapatite, sodium phosphate, iron phosphate, aluminum phosphate, lithium iron phosphate, especially lithium iron phosphate or lithium iron manganese phosphate, or phosphinic acid, phosphoric acid, their respective polyacids or anhydrides, or mixtures thereof.

[0014] Preferably, the phosphorus-oxygen compound-containing material contains calcium phosphate, particularly its corresponding orthophosphate, metaphosphate, polyphosphate, or mixtures thereof. Particularly preferred calcium phosphate is calcium phosphate, particularly orthophosphate, calcium metaphosphate, calcium hydroxyl apatite, or mixtures thereof.

[0015] Preferably, the phosphorus-oxygen compound-containing material contains at least one inorganic phosphate, particularly the corresponding orthophosphate, metaphosphate, polyphosphate, or a mixture thereof. Particularly preferably, it contains calcium phosphate, particularly preferably calcium orthophosphate or calcium hydroxyl apatite.

[0016] The phosphorus-oxygen compound-containing material preferably contains at least one phosphorus-oxygen compound in an amount calculated as elemental phosphorus of 1% to 44% by weight, preferably 1% to 30% by weight, and particularly preferably 5% to 28% by weight, based on the phosphorus-oxygen compound-containing material.

[0017] Similarly preferred is a process characterized in that the phosphorus-oxygen compound-containing material is sewage sludge ash or iron phosphate-containing black mass.

[0018] Sewage sludge ash is preferably understood to mean the solid residue produced in both sewage sludge combustion and sewage sludge gasification for fuel gas production. Sewage sludge ash consists of various components, for example, preferably aluminum phosphate, iron phosphate, e.g., calcium iron phosphate, e.g., Ca9Fe(PO4)7, or whitlockite (Ca3(PO4)2), gypsum, calcium hydroxide, calcium oxide and calcium carbonate, iron oxide, e.g., hematite (Fe2O3), and quartz (SiO2), indialites (Mg2Al4Si5O 18 ) may contain such as.

[0019] The sewage sludge ash preferably contains a phosphorus-oxygen compound having a content calculated as 1.5% to 13.1% by weight of phosphorus based on the phosphorus-oxygen compound-containing material, particularly phosphate, preferably an iron compound of 1% to 21% (calculated as elemental iron) and an aluminum compound of 0.7% to 20.2% (calculated as elemental aluminum) in each case based on the phosphorus-oxygen compound-containing material. Preferably, the total of the iron compound and the aluminum compound is 1.7% to 41.2% calculated as each elemental metal.

[0020] The sewage sludge ash usually contains further typical elements calculated for each element: 4% to 38% by weight of calcium, 0% to 2% by weight of potassium, 0.1% to 4% by weight of magnesium, 0.1% to 4% by weight of sodium, 0% to 7% by weight of sulfur, 0% to 24% by weight of silicon, 0% to 2% by weight of titanium and may contain.

[0021] The total amount of these elements calculated together as oxides preferably amounts to more than 70% of the weight of the sewage sludge ash.

[0022] Each component is preferably in the form of an oxide, phosphate or sulfate. The iron compound is preferably in the form of an iron (III) compound in the range of 50 to 100% by weight. More than 80% by weight of the phosphate is preferably in the form of a metal phosphate of aluminum, calcium or iron. Further, the sewage sludge ash may contain trace amounts of a number of further elements, particularly copper, zinc, lead, barium and manganese. The aforementioned silicon is substantially present in the form of sand mainly derived from the filtration process practiced at sewage treatment plants.

[0023] The phosphorus-oxygen compound-containing material may, in a preferred form, consist of 100% iron phosphate compounds or contain only a portion thereof. Preferably, the material used contains iron phosphate compounds in total amount calculated as elemental phosphorus at a content of 1% to 22% by weight, preferably 10% to 21% by weight, based on the phosphorus-oxygen compound-containing material. Preferably used materials include iron phosphate, particularly iron(II) phosphate, iron(III) phosphate and iron(III) pyrophosphate, lithium iron phosphate (LFP), lithium iron manganese phosphate (LFMP), particularly LiFe (1-x) Mn x It contains at least one iron phosphate compound selected from the group consisting of LFP and / or LFMP having PO4 (wherein 0 ≤ x < 0.9, especially 0 ≤ x < 0.6), or mixtures thereof.

[0024] Preferably, an LFP and / or LFMP-containing material containing LiFe(1-x)MnxPO4 of the above formula is preferred. Therefore, the process according to the present invention particularly uses a material containing LFP and / or LFMP in proportions of 2% to 100% by weight, preferably 40% to 99% by weight, especially 50% to 99% by weight, and especially preferably 70% to 99% by weight. Preferably, the composition of the material used can also be described in each case by determining the weight fraction of a particular element in the preferably LFP and / or LFMP-containing material used, based on the amount of material, and the material used is preferably as follows: 1% to 36% by weight of Fe, Preferably, 0.4% to 20% by weight as elemental phosphorus, calculated based on the LFP and / or LFMP-containing material. Mn in a weight of 0% to 35% 1% to 8% by weight of Li, 1% to 55% by weight, preferably 1% to 40% by weight, and especially 1% to 30% by weight of carbon It contains these elements. These elemental amounts may originate from LFP or LFMP, but may also originate from other components of the material used, such as residues of metallic components.

[0025] The elemental content is preferably determined by conventional elemental analysis methods. The type and amount of iron phosphate compounds present are preferably determined by powder reflection X-ray diffraction (XRD) using Cu-Kα emission. The obtained diffraction patterns are compared with, for example, the database of the ICDD (International Centre for Diffraction Data) and assigned to the obtained iron phosphate-containing phase.

[0026] For lithium iron phosphate, the reflection from JCPDS (International Centre for Powder Diffraction Data Sample) card #83-2092 is used for comparison as specified herein. Preferably, the material used further contains 1% to 55% by weight, preferably 1% to 40% by weight, and especially 1% to 30% by weight of carbon, particularly graphite and / or carbon black. Preferably, the total amount of LFP and / or LFMP and carbon in the preferably LFP and / or LFMP-containing material used is greater than 70% by weight, preferably greater than 80% by weight, and especially preferably greater than 90% by weight. LFP and / or LFMP-containing battery cells are usually mechanically crushed as much as possible, and the residue containing the cathode and anode materials, binder and other components is pulverized into a mass. This mass is black due to the dark color of the LFP / LFMP and graphite-containing anode material and is therefore called "black mass". As a result of technically incomplete separation, the black mass may also contain other battery components, such as metallic residues.

[0027] Therefore, phosphorus-oxygen compound-containing materials may also be so-called black mass, containing a proportion of phosphate compounds ranging from 0.4% to 21% by weight, calculated as elemental phosphorus based on the phosphorus-oxygen compound-containing material.

[0028] The materials used may also contain metals, preferably in amounts of 0% to 15% by weight, and particularly preferably 0% to 5% by weight, and specifically may include Al, Cu, Co, and Ni.

[0029] The proportion of aluminum determined as elemental aluminum in the material used is preferably less than 10% by weight, and particularly preferably less than 5% by weight.

[0030] The material used preferably contains less than 10% by weight of polymer particles, more preferably less than 1% by weight, and more preferably less than 0.1% by weight of plastics, particularly polyethylene and / or polypropylene.

[0031] The LFP and / or LFMP-containing material used is preferably black mass from battery pulverized material.

[0032] The materials used or the phosphorus-oxygen compounds used preferably have an average particle size of 0.1 μm to 50 mm, preferably 0.5 to 10 mm. The particle size can be easily determined by sieving, depending on the dimensions, or by laser diffraction or laser scattering for finer particles. The optimal method to be used in each case is well known to those skilled in the art. Preferably, the LFP and / or LFMP-containing material used may be a coating material. Preferred coating materials include carbon, particularly graphite and metal oxides.

[0033] The moisture content of the phosphorus-oxygen compound used or the material used is preferably less than 5% by weight, and particularly less than 1% by weight.

[0034] process The phosphorus-oxygen compound-containing material is reacted in the presence of tetrachloroethene. This can be used as is, or in the form of its precursor chloroform (which detaches HCl at temperatures above 500°C and is converted to tetrachloroethene), or in the form of a mixture containing tetrachloroethene and chloroform.

[0035] The thermal decomposition of chloroform to tetrachloroethene produces HCl, which is unnecessary for further reactions with phosphorus-oxygen compounds; therefore, it is preferable to use tetrachloroethene as a reactant when available.

[0036] The reaction is optionally carried out in the presence of an inert gas. Useful inert gases include, for example, nitrogen, carbon dioxide, and / or argon. Tetrachloroethene is optionally used together with chloroform and optionally a carrier gas, and preferably contains less than 0.1% by volume, and particularly less than 0.05% by volume, of oxygen based on the total volume of the gas stream containing these components. Preferably used inert gases are nitrogen, carbon dioxide, or argon.

[0037] A weight ratio of 1:0 to 1:6, preferably 1:0 to 1:4, between the total amount of tetrachloroethene and / or chloroform and the inert gas is preferred.

[0038] The reaction of the phosphorus-oxygen compound-containing material is preferably carried out in a furnace such as a fluidized bed, packed bed, or moving bed reactor, a shaft furnace, or, in its simplest form, an indirectly heated tubular furnace or a rotary tubular furnace. Each reactor is preferably airtight. The material may be optionally formed before being introduced into the furnace, for example, by briquetting, extrusion, pelletization, etc. For this purpose, phyllosilicates, especially bentonite, and auxiliary agents such as lignosulfonates, methylcellulose, water glass, and starch may be used.

[0039] The phosphorus-oxygen compound-containing material used in accordance with the process of the present invention is preferably introduced into a reactor equipped with a layer resistant to the set reaction conditions. Preferred reactor materials are nickel or graphite-coated reactors. Reactors that allow for the movement of the material during the reaction and enable contact and heat distribution of the reactants as effectively as possible are particularly preferred. Reactions in fluidized bed apparatus and rotary tube reactors, or in extruder apparatus with screw propulsion, are preferred.

[0040] In the case of a tubular reactor, the reactor length is preferably 0.2 to 40 m. The reactor residence time during the reaction is generally determined by the temperature and the possibility of contact between the reactants. The process according to the present invention can be carried out in batch or continuous manner.

[0041] A gas stream of tetrachloroethene and / or chloroform, optionally diluted with an inert carrier gas stream, is passed through the reactor and over phosphorus-oxygen compounds or materials containing them, while simultaneously maintaining the reaction temperature at 500°C to 1000°C, preferably 600°C to 900°C, and particularly 700°C to 850°C. The reaction time may be several minutes to 10 hours, preferably 20 minutes to 5 hours.

[0042] Preferably, 0.75 to 4 moles of tetrachloroethene or 1 to 4.5 moles of chloroform are used per mole of phosphorus in the phosphorus-oxygen compound-containing material.

[0043] It is preferable to resublimate the products formed during the reaction, which may become volatile at the reaction temperature, in this example particularly phosphoryl chloride, iron chloride, aluminum chloride, and optionally other heavy metal chlorides such as zinc chloride or rare earth element chlorides, from the exhaust gas flow at different cooling points and recover them separately.

[0044] The preferred precipitation temperature for FeCl2 is below 701°C, particularly below 700°C to 307°C. For FeCl3, it is 307°C or lower, particularly between 150°C and 300°C, and for AlCl3, it is 150°C or lower, particularly between 110°C and 149°C.

[0045] The phosphoryl chloride is preferably recovered in a cooler at a temperature of less than 110°C.

[0046] Both the sublimes and residues are essentially water-soluble and, preferably, can be further separated and isolated from their aqueous solutions. For example, after confirming their potential presence using conventional H2S separation procedures, they can be separated and isolated from each other as sulfides, chlorides, phosphates, fluorides, or other precipitated compounds. [Examples]

[0047] analysis The calcium phosphate samples used were dissolved in a suitable acid, and each element was calibrated using calibration standard solutions for each element before analysis was performed using ICP-OES.

[0048] Example 1 Ten g of industrial-grade calcium phosphate (obtained from sewage sludge ash treatment), containing Ca: 35 wt%, PO4: 52 wt%, Fe: 0.14 wt%, and Al: 0.48 wt% (each determined by ICP-OES), is placed in a quartz reactor (120 mm in diameter) located inside a tubular furnace. The reactor is heated to 150°C.

[0049] Tetrachloroethene is evaporated at a rate of 0.2 ml / min in a total evaporator and mixed with a nitrogen gas stream (1 l / min) at 150°C. The tetrachloroethene-nitrogen mixture enters a quartz reactor heated to 150°C to avoid condensation of the reactants and passes over calcium phosphate. The gaseous reaction products are discharged from the reactor as an exhaust gas stream, cooled to 100°C, and passed through a gas cell equipped with an optical window. The infrared spectrum of the gas phase is recorded through this window. Heating at this stage of the reaction is used solely to avoid condensation of the reactants and products.

[0050] The solid is heated to 780°C in a reactor, and a gas flows through it for 2 hours. The exhaust gas flow is continuously monitored using IR spectral recording.

[0051] It is also possible to heat the sample to 780°C before adding tetrachloroethene.

[0052] At temperatures above 750°C, the POCl3 formation reaction begins to accelerate, which is evidenced by the IR band (observed value: 592 cm⁻¹). -1 (P-Cl), 1322cm -1 (P=O), Literature value: 590 cm -1 and 1322cm -1 (±6cm -1), Shimanouchi, T., Tables of Molecular Vibrational Frequencies Consolidated Volume II, J. Phys. Chem. Ref. Data, 1972, 6, 3, 993-1102).

[0053] Collect POCl3 in a condenser.

[0054] After the reaction is complete, 13.2 g of a black solid is also obtained due to the residue of carbon black. This solid consists essentially of CaCl2 and is partially molten. This solid reaction product is soluble in water and can be used for further applications, such as phosphate precipitation in sewage treatment plants.

[0055] Example 2 50 g of industrial-grade calcium phosphate (obtained from sewage sludge ash treatment), containing Ca: 35 wt%, PO4: 52 wt%, Fe: 0.14 wt%, and Al: 0.48 wt% (each determined by ICP-OES), is placed in a quartz reactor (120 mm in diameter) located inside a tubular furnace. The reactor is heated to 150°C.

[0056] Chloroform is evaporated at a rate of 0.2 ml / min in a total evaporator and mixed with a nitrogen stream (1 l / min) at 100°C. The chloroform-nitrogen mixture enters a quartz reactor heated to 150°C to avoid condensation of the reactants and passes over calcium phosphate. The gaseous reaction products are discharged from the reactor, cooled to 100°C, and passed through a gas cell equipped with an optical window. The infrared spectrum of the gas phase is recorded through this window. Heating at this stage of the reaction is used solely to avoid condensation of the reactants and products.

[0057] The solid is heated to 780°C in a reactor, and a gas flows through it for 2 hours. The off-gas flow, which is simultaneously discharged, is continuously monitored using IR spectral recording.

[0058] It is also possible to heat the sample to 780°C before adding chloroform.

[0059] At temperatures above 500°C, chloroform decomposes into HCl and tetrachloroethene.

[0060] At temperatures above 600°C, the generated tetrachloroethene rapidly reacts with the initially charged calcium phosphate to produce calcium chloride and phosphoryl chloride. POCl3 is collected in a condenser. The latter can be identified by characteristic bands in its infrared spectrum. Above 750°C, the reaction reaches a rate at which a significant conversion rate can be achieved. The reaction is terminated 20 minutes after reaching the target temperature of 780°C.

Claims

1. i. React a phosphorus-oxygen compound-containing material in the presence of tetrachloroethene at a temperature of 500°C to 1000°C. ii. Deriv the generated phosphorus-chlorine compounds, particularly phosphorus oxychloride, into the exhaust gas stream and isolate them. A process for producing phosphorus-chlorine compounds, characterized by the following features.

2. A process for producing a phosphorus-chlorine compound according to claim 1, characterized in that the reaction is carried out at a temperature of 600°C to 900°C, particularly 700°C to 850°C.

3. A process for producing a phosphorus-chlorine compound according to claim 1 or 2, characterized in that the phosphorus-chlorine compound is phosphorus oxychloride.

4. A process for producing a phosphorus-chlorine compound according to any one of claims 1 to 3, characterized in that the phosphorus-oxygen compound-containing material contains phosphate, particularly calcium phosphate, apatite, particularly chloroapatite or hydroxylapatite, sodium phosphate, iron phosphate, aluminum phosphate, lithium iron phosphate, particularly lithium iron phosphate or lithium iron manganese phosphate, or phosphinic acid, phosphoric acid, each of the polyacids or anhydrides thereof, or mixtures thereof.

5. A process for producing a phosphorus-chlorine compound according to any one of claims 1 to 4, characterized in that the phosphorus-oxygen compound-containing material contains at least one inorganic phosphate, particularly the corresponding orthophosphate, metaphosphate, or polyphosphate, or a mixture thereof.

6. A process for producing a phosphorus-chlorine compound according to any one of claims 1 to 5, characterized in that the phosphorus-oxygen compound-containing material contains calcium phosphate, particularly preferably calcium orthophosphate, calcium metaphosphate and / or calcium hydroxyl apatite.

7. A process for producing a phosphorus-chlorine compound according to any one of claims 1 to 6, characterized in that the phosphorus-oxygen compound-containing material contains at least one phosphorus-oxygen compound in an amount calculated as 1% to 44% by weight, preferably 1% to 30% by weight, and particularly 5% to 28% by weight, of elemental phosphorus based on the phosphorus-oxygen compound-containing material.

8. A process for producing a phosphorus-chlorine compound according to any one of claims 1 to 7, characterized in that the phosphorus-oxygen compound-containing material is sewage sludge ash or iron phosphate-containing black mass.

9. A process for producing a phosphorus-chlorine compound according to any one of claims 1 to 8, characterized in that the phosphorus-oxygen compound-containing material has an average particle size of 0.1 μm to 50 mm, preferably 0.5 to 10 mm.

10. A process for producing a phosphorus-chlorine compound according to any one of claims 1 to 9, characterized in that tetrachloroethene and / or chloroform are optionally used together with an inert gas in the reaction of the phosphorus-oxygen compound-containing material.

11. A process for producing a phosphorus-chlorine compound according to any one of claims 1 to 10, characterized in that phosphoryl chloride is discharged from the exhaust gas flow and separated by condensation, preferably at a temperature below 110°C.

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