Processing and refining of carbonaceous materials

Abstract

To provide a process for processing and purification of carbonaceous materials, especially carbon black, that does not require high acid concentrations or the use of organic solvents.SOLUTION: The present invention relates to a process for the processing and / or purification of carbonaceous solids, comprising the steps of: a) providing a mixture comprising a carbonaceous solid and at least one inorganic compound, b) providing an aqueous fluid comprising a nitrogen hydride, c) providing an alkali hydroxide and / or an alkali metal, d) contacting the mixture of step a), the fluid of step b) and the alkali metal hydroxide and / or alkali metal of step c), e) subjecting the composition obtained in step d) to a reduced or increased temperature and / or to a reduced or increased pressure, and f) separating a carbonaceous solid from the composition obtained in step e).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for treating and / or purifying carbonaceous solids and to the use of nitrogen hydrides as dispersants for the preparation and / or stabilization of aqueous suspensions. [Background technology]

[0002] Carbon-rich materials such as soot, activated carbon, certain pyrolysis products, graphite electrodes and a vast array of other graphite-based materials are of great industrial importance.

[0003] An important carbon-rich material is industrial soot, also known as carbon black. In contrast to conventional soot, carbon black is produced by the targeted pyrolysis of carbonaceous materials to produce specific products. These specific production processes allow for the synthesis of nanometer-level carbon black particles whose primary particle size and surface structure are tailored to each application range. Annual carbon black production was approximately 8 million tons in 1996 and is expected to increase to over 15 million tons by 2022. Carbon black is primarily used as an additive in a wide range of rubber products (rubber black) and as a colorant in plastics, paints, coatings, and inks (pigment black). The majority of carbon black is used in the tire industry, accounting for approximately 85% of the world's annual production. The production of newly manufactured carbon black (virgin carbon black) requires significant amounts of raw materials and energy and generates significant amounts of carbon dioxide. At the same time, for example, the European Union generates approximately 3.2 million tons of scrap tires annually, while the United States generates 4.4 million tons. Efforts have already been made to recycle carbon black from old materials such as scrap tires. Known recycling processes typically involve pyrolysis of the waste and subsequent processing of the resulting pyrolysis residue. However, the carbon black obtained in this way (recovered carbon black) has only about 80% of the carbon content of newly produced carbon black and is therefore not yet a suitable substitute. In particular, recovered carbon black often contains a high proportion of ash, typically consisting of zinc sulfide, zinc oxide, silicon dioxide, and / or aluminum oxide. This high ash content limits the range of possible applications and therefore reduces the value of the recycled product. When reused in tire manufacturing, the ash content in recovered carbon black can, for example, reduce the strength and durability of the rubber.When used as a colorant in plastics, paints, lacquers, or inks, the poor color or black quality of recovered carbon black is a limiting factor.

[0004] For example, a method for removing ash from scrap tires is known from US patent application US20150307714A1. Chinese patent application CN109266376 relates to a method for recycling and decomposing scrap tires using peroxides and organic solvents at high temperature and pressure. Chinese patent application CN108384287 also relates to a method for recycling and decomposing scrap tires. US patent application US2018320082A1 relates to a method for recycling scrap tires using microwave irradiation. International patent application WO2013175488A2 is known to provide a method for providing carbon black with a low sulfur content.

[0005] One of the drawbacks of known methods is, for example, the use of high acid concentrations or organic solvents, which are problematic from a health, environmental or handling standpoint. In addition, prior art methods often require long extraction times and / or only allow the recovery of structurally and morphologically altered, low-quality carbon black.

[0006] It is desirable to develop new methods for processing and purifying carbonaceous materials that do not suffer from the above-mentioned drawbacks. There is a need for efficient methods for processing and purifying carbonaceous materials, particularly carbon black. There is also a need for methods for processing and purifying carbonaceous materials, particularly carbon black, that do not require high acid concentrations or organic solvents. There is also a need for methods for processing and purifying carbonaceous materials, particularly carbon black, that do not require long extraction times and / or that allow for the recovery of carbon-rich materials, particularly carbon black, with little structural or morphological alteration. There is also a need for methods for processing and purifying carbonaceous materials, particularly carbon black, that provide products with high purity and / or low ash content. In particular, there is a need for methods for recovering and purifying carbon black from scrap tires that provide recovered carbon black with similar or ideally identical qualities to newly produced carbon black, particularly low ash and / or sulfur content, and with physical properties that are little changed from the carbon black originally used. Summary of the Invention [Problem to be solved by the invention]

[0007] It is therefore an object of the present invention to provide a method for treating and purifying carbonaceous materials that does not suffer from the above-mentioned drawbacks. A further object is to provide an efficient method for treating and purifying carbonaceous materials, particularly carbon black. A further object is to provide a method for treating and purifying carbonaceous materials, particularly carbon black, that does not require high acid concentrations or the use of organic solvents. Another object is to provide a method for treating and purifying carbonaceous materials, particularly carbon black, that does not require long extraction times and / or allows for the recovery of carbon black that is largely structurally and morphologically unchanged. A further object is to provide a method for treating and purifying carbonaceous materials, particularly carbon black, that provides a product with high purity and / or low ash content. In particular, one object of the present invention is to provide a method for recovering and purifying carbon black from used tires, which provides recovered carbon black that has similar or ideally identical qualities to newly produced carbon black, particularly low ash and / or sulfur content, and whose physical properties are largely unchanged from the carbon black originally used. [Means for solving the problem]

[0008] One or more of the above objectives are achieved by the method of treating and / or purifying carbonaceous solids of the present invention, which method of treating and / or purifying carbonaceous solids comprises the steps of: a) providing a mixture having a carbonaceous solid and at least one inorganic compound; b) providing an aqueous fluid having nitrogen hydride; c) providing an alkali and / or alkali metal hydroxide; d) contacting the mixture of step a), the fluid of step b) and the alkali and / or alkali metal hydroxide of step c); e) subjecting the composition obtained in step d) to reduced or elevated temperature and / or reduced or elevated pressure, f) separating the carbonaceous solids from the composition obtained in step e).

[0009] The inventors have surprisingly found that the method of the present invention can be used to selectively remove inorganic compounds, such as minerals and / or salts, from a carbon-rich solid mixture or suspension thereof. Furthermore, the inventors have found that carrying out the method of the present invention does not change, or does not significantly change, the physical properties of the carbon present in the original mixture. Thus, the method of the present invention makes it possible to provide solids with very high carbon content and high functionality, suitable for further processing or use at a later stage.

[0010] Process a) In step a) of the method of the present invention, a mixture comprising a carbonaceous solid and at least one inorganic compound is provided.

[0011] For purposes of the present invention, an "inorganic compound" is a compound that does not contain carbon-hydrogen bonds, preferably does not contain carbon.

[0012] For purposes of the present invention, a carbonaceous "solid" is understood to be a carbonaceous material that is sparingly soluble in water, preferably very sparingly soluble in water, and more preferably insoluble in water. As used herein, "sparingly water-soluble" refers to a material having a solubility of 1 to 10 g / L (H2O) at 25°C. As used herein, "very sparingly water-soluble" refers to a material having a solubility of 0.1 to 1 g / L (H2O) at 25°C, and "water-insoluble" refers to a material having a solubility of less than 0.1 g / L (H2O) at 25°C (e.g., in the range of 0.0001 to 0.1 g / L (H2O)).

[0013] The carbonaceous solid can consist of at least 80% (e.g., in the range of 80.0 to 99.8%), preferably at least 90%, and more preferably at least 95% (e.g., in the range of 95.0 to 99.8%) carbon. In one embodiment of the invention, the carbon-containing solid is present in the crystalline modification of graphite.

[0014] It is particularly preferred that the carbonaceous solid comprises or consists of carbon black. For example, the carbonaceous solid may consist of at least 90%, preferably at least 95%, of carbon black. The primary particles of carbon black may have a particle size ranging from 1 to 600 nm, preferably from 10 to 300 nm. The particle size of the primary particles can be measured, for example, by laser diffraction. The primary particles of carbon black can combine to form carbon black aggregates having a diameter ranging from 80 to 800 nm. These carbon black aggregates can further form superstructures in the form of carbon black agglomerates. Furthermore, the carbon black may have a particle size ranging from 5 to 1500 nm, as measured according to the BET method. 2 / g, preferably 15 to 600m 2 In one embodiment of the present invention, the carbonaceous solid in step a) comprises carbon black having an elemental composition of 90.0-99.7% C, 0.1-0.6% H, 0.01-0.8% S, and 0.2-3.5% O.

[0015] The at least one inorganic compound is preferably two or more inorganic compounds. The at least one inorganic compound may be an inorganic substance and / or a salt, preferably a mixture of inorganic substances and / or salts. In one aspect of the present invention, the at least one inorganic compound is selected from the group consisting of one or more metal sulfides, one or more metal oxides, one or more silicates, and mixtures thereof. For example, the at least one inorganic compound may comprise or consist of zinc sulfide, zinc oxide, silicon dioxide, silicates, aluminum oxide, or mixtures thereof.

[0016] The at least one inorganic compound may be sparingly soluble in water, preferably very sparingly soluble in water, and most preferably insoluble in water, with the above definitions of "sparingly soluble in water," "very sparingly soluble in water," and "insoluble in water" applying.

[0017] The at least one inorganic compound is preferably an inorganic compound selected from the group consisting of one or more metal sulfides, one or more metal oxides, one or more silicates, and mixtures thereof, and the at least one inorganic compound is at least poorly water-soluble, more preferably at least very poorly water-soluble, and most preferably insoluble in water.

[0018] The mixture can be in the form of a solid mixture or a suspension. In one embodiment, the mixture is present as a suspension, preferably an aqueous suspension. In another embodiment, the mixture is present as a solid mixture.

[0019] According to one embodiment of the present invention, the mixture of step a) comprises the carbonaceous solid in a molar fraction of more than 50% (e.g. in the range of 50-99%), preferably more than 70%, more preferably more than 80% (e.g. in the range of 80-95%), relative to the total molar amount of the mixture, and / or the mixture of step a) comprises the at least one inorganic compound in a molar fraction of 1-30%, preferably 5-20%, relative to the total molar amount of the mixture.

[0020] In one embodiment of the invention, the mixture of step a) has a molar fraction of the carbonaceous solid greater than 50% (e.g., in the range of 50-99%), preferably greater than 70%, more preferably greater than 80% (e.g., in the range of 80-95%), based on the total molar amount of the mixture, and the at least one inorganic compound in a molar fraction of 1-30%, preferably 5-20%, based on the total molar amount of the mixture.

[0021] In a further embodiment of the invention, the mixture of step a) comprises more than 50 wt. % (e.g. in the range of 50-99%), preferably more than 70 wt. %, more preferably more than 80 wt. % (e.g. in the range of 80-95%) of said carbonaceous solids relative to the total weight of said mixture, and / or the mixture of step a) comprises 1-30 wt. %, preferably 5-20 wt. % of said at least one inorganic compound relative to the total weight of said mixture.

[0022] In one embodiment of the invention, the mixture of step a) has the carbonaceous solid in an amount greater than 50 wt. % (e.g., in the range of 50-99%), preferably greater than 70 wt. %, more preferably greater than 80 wt. % (e.g., in the range of 80-95%), based on the total weight of the mixture, and the at least one inorganic compound in an amount of 1-30 wt. %, preferably 5-20 wt. %, based on the total weight of the mixture.

[0023] In one aspect of the invention, the mixture of step a) comprises the carbonaceous solid in an amount of 70 to 99 wt.%, more preferably 80 to 98 wt.%, based on the total weight of the carbonaceous solid and the at least one inorganic compound, and / or the mixture of step a) comprises the at least one inorganic compound in an amount of 1 to 30 wt.%, preferably 2 to 20 wt.%, based on the total weight of the carbonaceous solid and the at least one inorganic compound.

[0024] In one aspect of the invention, the mixture of step a) has the carbonaceous solid in an amount of 70 to 99 wt.%, more preferably 80 to 98 wt.%, based on the total weight of the carbonaceous solid and the at least one inorganic compound, and has the at least one inorganic compound in an amount of 1 to 30 wt.%, preferably 2 to 20 wt.%, based on the total weight of the carbonaceous solid and the at least one inorganic compound.

[0025] The weight percentage of the carbonaceous solids in the mixture of step (a) and / or the at least one inorganic compound in the mixture of step (a) may be measured according to the standard method "ASTM D150615-; Standard Test Methods for Carbon Black Ash-Content".

[0026] In one embodiment of the present invention, the mixture of step a) is obtained by pyrolysis of a carbonaceous material. Preferably, the mixture of step a) is obtained by pyrolysis of scrap tires or biomass, preferably scrap tires. Thus, according to a preferred embodiment, the mixture of step a) is obtained by pyrolysis of scrap tires. According to another embodiment, the mixture of step a) is obtained by pyrolysis of biomass.

[0027] According to another preferred embodiment, the mixture of step a) is obtained from the pyrolysis of scrap tires and comprises carbonaceous solids and at least one inorganic compound, said carbonaceous solids comprising carbon black, and said at least one inorganic compound being an inorganic compound selected from the group consisting of one or more metal sulfides, one or more metal oxides, one or more silicates and mixtures thereof.

[0028] According to another preferred aspect, the mixture of step a) is obtained from the pyrolysis of scrap tires and comprises carbonaceous solids and at least one inorganic compound, said carbonaceous solids comprising carbon black, said at least one inorganic compound comprising an inorganic compound selected from the group consisting of one or more metal sulfides, one or more metal oxides, one or more silicates and mixtures thereof, said at least one inorganic compound being at least sparingly water-soluble, more preferably at least very sparingly water-soluble, and most preferably insoluble in water.

[0029] According to another preferred aspect, the mixture of step a) is obtained from the pyrolysis of scrap tires and comprises carbonaceous solids and at least one inorganic compound, wherein the carbonaceous solids consist of more than 90% (e.g., in the range of 90-99.8%) carbon and the at least one inorganic compound is an inorganic compound selected from the group consisting of one or more metal sulfides, one or more metal oxides, one or more silicates and mixtures thereof, and wherein the mixture has a molar fraction of the carbonaceous solids of more than 70% and a molar fraction of the at least one inorganic compound of 5-20% based on the total molar amount of the mixture.

[0030] According to another preferred embodiment, the mixture of step a) is obtained from the pyrolysis of scrap tires and comprises carbonaceous solids and at least one inorganic compound, the carbonaceous solids consisting of more than 90% (e.g., in the range of 90 to 99.8%) carbon black, the at least one inorganic compound being an inorganic compound selected from the group consisting of one or more metal sulfides, one or more metal oxides, one or more silicates and mixtures thereof, the mixture having a molar fraction of the carbonaceous solids of more than 70% (e.g., in the range of 70 to 95%) and a molar fraction of the at least one inorganic compound of 5 to 20% based on the total molar amount of the mixture.

[0031] According to another preferred embodiment, the mixture of step a) is obtained from the pyrolysis of scrap tires and comprises carbonaceous solids and at least one inorganic compound, the carbonaceous solids consisting of more than 90% (e.g. in the range of 90-99.8%) carbon, the at least one inorganic compound being an inorganic compound selected from the group consisting of one or more metal sulfides, one or more metal oxides, one or more silicates and mixtures thereof, the mixture comprising the carbonaceous solids in an amount of more than 70 wt.% (e.g. in the range of 70-95%) and the at least one inorganic compound in an amount of 5-20 wt.%, based on the total weight of the mixture.

[0032] According to another preferred embodiment, the mixture of step a) is obtained from the pyrolysis of scrap tires and comprises carbonaceous solids and at least one inorganic compound, the carbonaceous solids consisting of more than 90% (e.g. in the range of 90-99.8%) carbon black, the at least one inorganic compound being an inorganic compound selected from the group consisting of one or more metal sulfides, one or more metal oxides, one or more silicates and mixtures thereof, the mixture comprising the carbonaceous solids in an amount of more than 70 wt.% (e.g. in the range of 70-95%) and the at least one inorganic compound in an amount of 5-20 wt.%, based on the total weight of the mixture.

[0033] Step b) In step b) of the method of the present invention, an aqueous fluid having a nitrogen hydride is provided. In the present invention, a "nitrogen hydride" is a chemical substance having at least one nitrogen-hydrogen bond. In the present invention, an aqueous "fluid" is an aqueous suspension, emulsion, solution, or dispersion, preferably an aqueous solution. In the present invention, an aqueous "fluid" is preferably a water-based fluid comprising at least 50 wt. % (e.g., in the range of 50 to 95 wt. %), more preferably 75 wt. % water, based on the total weight of the fluid.

[0034] The inventors have surprisingly found that the use of an aqueous fluid having a nitrogen hydride is beneficial to the stability of the suspension of the carbonaceous starting material and process reagents. Furthermore, the inventors have surprisingly found that the use of the fluids described herein improves the extraction of inorganic compounds from the carbonaceous starting material.

[0035] According to one embodiment of the present invention, the fluid of step b) comprises a nitrogen hydride selected from the group consisting of ammonia, inorganic ammonium salts, primary or secondary organic amines and their ammonium salts, and mixtures thereof.

[0036] Preferably, the fluid comprises a nitrogen hydride selected from the group consisting of ammonia, ammonium hydroxide, ammonium halides, guanidine, guanidine derivatives and their ammonium salts, and mixtures thereof. More preferably, the fluid comprises the nitrogen hydride ammonia and / or ammonium hydroxide, most preferably ammonium hydroxide.

[0037] In one aspect, the aqueous fluid has the nitrogen hydride at a concentration of 0.001 to 16.5 mol / L, preferably 0.05 to 5 mol / L, and more preferably 0.09 to 0.9 mol / L. For example, the aqueous fluid may have the nitrogen hydride at a concentration of 0.05 to 0.25 mol / L.

[0038] According to one aspect of the present invention, in step b), the aqueous fluid is provided in an amount ranging from 2 L (fluid) / 1 kg (mixture of step a)) to 200 L (fluid) / 1 kg (mixture of step a)), preferably from 5 L (fluid) / 1 kg (mixture of step a)) to 150 L (fluid) / 1 kg (mixture of step a)), more preferably from 10 L (fluid) / 1 kg (mixture of step a)) to 100 L (fluid) / 1 kg (mixture of step a)).

[0039] According to one aspect of the present invention, in step b), the fluid is supplied in an amount ranging from 2 L (fluid) / 1 kg (of the mixture of step a)) to 200 L (fluid) / 1 kg (of the mixture of step a)), preferably from 5 L (fluid) / 1 kg (of the mixture of step a)) to 150 L (fluid) / 1 kg (of the mixture of step a)), and more preferably from 10 L (fluid) / 1 kg (of the mixture of step a)) to 100 L (fluid) / 1 kg (of the mixture of step a)), and the aqueous fluid contains the nitrogen hydride at a concentration of 0.001 to 16.5 mol / L, preferably from 0.05 to 5 mol / L, and more preferably from 0.09 to 0.9 mol / L.

[0040] The fluid of step b) may contain, in addition to said nitrogen hydride, one or more substances which may be adapted to the nature and / or amount of inorganic compounds in the mixture of step a).

[0041] According to an aspect of the present invention, the fluid comprises one or more substances selected from the group consisting of alcohols, oxidizers, acids, nitrates, and carbonates.

[0042] For example, the fluid may contain one or more alcohols. Water-miscible alcohols such as ethanol are suitable alcohols.

[0043] The fluid may contain one or more oxidizing agents. Suitable oxidizing agents are, for example, ozone, iodate, permanganate, peroxide or dichromate.

[0044] The fluid may contain one or more acids. Suitable acids are, for example, organic acids such as acetic acid and / or oxalic acid, or inorganic acids such as hydrochloric acid, sulfuric acid and / or phosphoric acid. However, in a preferred embodiment, no salt is added to the fluid.

[0045] Process c) In step c) of the process of the present invention, an alkali and / or alkali metal hydroxide is provided.

[0046] Preferably, an alkali hydroxide is provided in step (c). The alkali hydroxide can be provided in the form of a solid or a solution or suspension. Preferably, the alkali hydroxide is provided as a solid. In principle, the alkali hydroxide can be any known alkali hydroxide. However, it is preferred that the alkali hydroxide is selected from the group consisting of LiOH, NaOH, KOH or mixtures thereof, more preferably from the group consisting of NaOH, KOH or mixtures thereof. Most preferably, NaOH is used as the alkali hydroxide.

[0047] In another embodiment, an alkali metal, preferably sodium, is provided in step c).

[0048] According to one embodiment of the present invention, in step c) the alkali and / or alkali metal hydroxide is provided in a molar ratio relative to the inorganic compounds of the mixture of step a) ranging from 0.25:1 to 2:1, preferably from 0.5:1 to 1.5:1, more preferably from 0.75:1 to 1.25:1, and most preferably from 0.95:1 to 1.05:1.

[0049] According to one embodiment of the present invention, the alkali hydroxide, preferably NaOH, is provided in step c) in a molar ratio relative to the inorganic compounds of the mixture of step a) in the range of 0.25:1 to 2:1, preferably 0.5:1 to 1.5:1, more preferably 0.75:1 to 1.25:1, and most preferably 0.95:1 to 1.05:1.

[0050] According to one embodiment of the present invention, the alkali hydroxide, preferably NaOH, is provided in step c) in a molar ratio relative to the silicate present in the mixture of step a) in the range of 0.25:1 to 2:1, preferably 0.5:1 to 1.5:1, more preferably 0.75:1 to 1.25:1, most preferably 0.95:1 to 1.05:1.

[0051] According to another embodiment, the alkali hydroxide, preferably NaOH, is provided in step c) in stoichiometric amounts relative to the inorganic compounds of the mixture of step a). According to another embodiment, the alkali hydroxide, preferably NaOH, is provided in step c) in stoichiometric amounts relative to the silicates present in the mixture of step a).

[0052] Step d) In step d) of the process of the present invention, the mixture of step a), the aqueous fluid of step b) and the alkali and / or alkali metal hydroxide of step c) are contacted.

[0053] With regard to possible and preferred embodiments of the mixture of step a), the aqueous fluid of step b) and the alkali and / or alkali metal hydroxide of step c), reference is made to the explanations in the above sections.

[0054] The supplied materials can be contacted in step (d) without active mixing, for example without using a stirring unit. However, the supplied materials may also be stirred in step (d). In a preferred embodiment, the mixture of step a), the fluid of step b) and the alkali and / or alkali metal hydroxide of step c) are mixed in step d) of the present invention.

[0055] The contacting of the supplied materials may occur in any order or simultaneously. In one embodiment, the mixture of step a) is first contacted with the aqueous fluid of step b) and then contacted with the alkali and / or alkali metal hydroxide of step c). In a further embodiment, the aqueous fluid of step b) is first contacted with the alkali and / or alkali metal hydroxide of step c), and then contacted with the mixture of step a). In one embodiment, the mixture of step a) is simultaneously contacted with the aqueous fluid of step b) and the alkali and / or alkali metal hydroxide of step c).

[0056] It may be advantageous to first contact the mixture of step a) with the aqueous fluid of step b) and then add the alkali and / or alkali metal hydroxide of step c).Accordingly, according to a preferred embodiment of step d), the mixture of step a) is first contacted with the aqueous fluid of step b) and then contacted with the alkali and / or alkali metal hydroxide of step c).According to a more preferred embodiment of step d), the mixture of step a) is first mixed with the aqueous fluid of step b) and then mixed with the alkali and / or alkali metal hydroxide of step c).

[0057] The supplied materials can be contacted in one or more reactors. For example, the supplied materials can be mixed in a mixing unit. It is also possible to mix the materials sequentially in two different mixing units. Those skilled in the art are familiar with the corresponding reactors and equipment. According to one embodiment of the present invention, the mixture of step a) is first mixed with the aqueous fluid of step b) in a first mixing unit, and then the resulting composition is mixed with the alkali and / or alkali metal hydroxide of step c) in a second mixing unit.

[0058] Preferably, the reactor is equipped with a stirring device. Furthermore, the reactor may be equipped with one or more pumping devices and / or devices for adding solids. Those skilled in the art are familiar with such reactors and devices.

[0059] It is also possible to bring the supplied materials into direct contact in a reactor, which can then be used under the conditions of step e), which can be, for example, a pressure reactor or a hydrothermal reactor.

[0060] It may also be advantageous to heat the composition obtained in step d) to increase the homogeneity of the composition obtained in step d) and / or the solubility of the added solid. Consequently, according to one embodiment, step d) comprises heating the obtained composition. For example, the obtained composition can be heated to a temperature in the range of 25°C to 100°C.

[0061] Process e) In step e) of the process of the invention, the composition obtained in step d) is subjected to reduced or elevated temperature and / or reduced or elevated pressure, the terms "reduced" or "elevated" being taken as reference points of a temperature of 20° C. and / or a pressure of 1.013 bar.

[0062] Step (e) can be described as a leaching process, i.e., a type of liquid-solid extraction in which the more soluble fraction, i.e., inorganic compounds, are completely or partially removed from the insoluble, permeable solid phase in which the carbonaceous solid resides. Depending on the starting materials and reagents used in the process, different conditions may be used for such a process.

[0063] According to one embodiment of the present invention, the composition is subjected in step e) to a temperature of from -35°C to 400°C, preferably from 25°C to 300°C, more preferably from 80°C to 240°C, and / or the composition is subjected in step e) to a pressure of from 0.001 to 200 bar, preferably from 1 to 100 bar, more preferably from 5 to 50 bar, and / or the pH of the composition is adjusted in step e) to a value of from 0 to 14, preferably from 7 to 14, more preferably from 9 to 13.

[0064] According to another embodiment of the present invention, in step e), the composition is subjected to a temperature of from -35°C to 400°C, preferably from 25°C to 300°C, more preferably from 80°C to 240°C, and a pressure of from 0.001 to 200 bar, preferably from 1 to 100 bar, more preferably from 5 to 50 bar, and the pH of the composition is adjusted to a value of from 0 to 14, preferably from 7 to 14, more preferably from 9 to 13.

[0065] According to a preferred embodiment of the present invention, the composition obtained in step d) is subjected to high temperature and / or high pressure. According to a preferred embodiment of the present invention, the composition is subjected to a temperature of 50°C to 400°C and a pressure of 2 to 200 bar in step e). According to a preferred embodiment of the present invention, the composition is subjected to a temperature of 80°C to 400°C and a pressure of 5 to 200 bar in step e).

[0066] According to a preferred embodiment of the present invention, in step e), the composition is subjected to a temperature of 80° C. to 240° C. and a pressure of 5 to 50 bar, and the pH of the composition is adjusted to a value of 9 to 13.

[0067] The time for complete treatment of the composition according to step e) can be determined by those skilled in the art. Conventional quantitative and qualitative analytical methods such as conductivity measurement, pH measurement, mass spectrometry, powder diffraction, etc. can be used for this purpose.

[0068] In one embodiment, step e) is carried out for a time period in the range of 1 min to 24 h, preferably in the range of 5 min and 10 h, more preferably in the range of 15 min and 2 h.

[0069] Step e) of the process of the present invention may be carried out in stages. This means that the composition obtained in step d) can be subjected to a first condition of temperature and / or pressure and then to a second condition of a different temperature and / or pressure. Such a staged process is not limited to two stages, but may have three or more stages. The inventors have surprisingly found that a two-stage or more-stage process can improve the extraction of certain inorganic compounds from the composition being treated. For example, amorphous silica can be extracted from the composition in one stage, and crystalline silica can be extracted in another stage of the process.

[0070] In one embodiment of the invention, step e) is carried out stepwise under at least two different conditions of temperature, pressure and / or pH, preferably under at least two different conditions of temperature and pressure.

[0071] In one embodiment of the present invention, step e) is carried out in two or more stages, each stage having a different temperature and / or pressure. For example, step e) may be a two-stage process, in which in the first stage the composition obtained in step d) is subjected to a temperature in the range of 100-200°C, preferably in the range of 160-180°C, and a pressure in the range of 0.01-50 bar (e.g., in the range of 2-50 bar), preferably 0.1-15 bar (e.g., in the range of 2-15 bar), followed by a second stage at a temperature in the range of 150-300°C, preferably in the range of 180-200°C, and a pressure in the range of 0.01-50 bar (e.g., in the range of 2-50 bar), preferably 10-20 bar.

[0072] An additional aqueous fluid of step b) and / or an additional alkali and / or alkali metal hydroxide of step c) can also be added to the composition in step e). According to one embodiment, step e) comprises adding an additional aqueous fluid of step b) and / or an additional alkali and / or alkali metal hydroxide of step c).

[0073] After removing the aqueous phase, an additional aqueous fluid of step b) and / or an additional alkali and / or alkali metal hydroxide of step c) can also be added. According to one embodiment, step e) comprises removing the aqueous phase and then adding an additional aqueous fluid of step b) and / or an additional alkali and / or alkali metal hydroxide of step c).

[0074] Step e) can be carried out in a reactor designed for temperatures between -35°C and 400°C and pressures between 0.001 and 200 bar. Such reactors are known to those skilled in the art. For example, step e) can be carried out in a pressure reactor or a hydrothermal reactor. Furthermore, step e) can be carried out in a batch reactor, a semi-batch reactor or a flow-through reactor, preferably a batch reactor or a semi-batch reactor.

[0075] Process f) In step f) of the process of the present invention, the carbonaceous solids are separated from the composition obtained in step e).

[0076] The carbonaceous solids can be separated by filtration. According to a preferred embodiment, step f) comprises filtering the carbonaceous solids, in which case the carbonaceous solids are obtained as a residue and an aqueous filtrate is obtained.

[0077] A suitable means of filtration can be selected by one skilled in the art. For example, carbonaceous solids can be separated by mechanical filtration using a filtration membrane. Suitable filtration membranes include microfiltration membranes. In one embodiment, a filtration membrane is used having an average pore size of more than 1 μm, preferably 1 to 100 μm, more preferably 1 to 50 μm, and most preferably 1 to 20 μm.

[0078] The inventors of the present invention have surprisingly found that the carbonaceous solids of step f) have the same or only slightly different physical properties than the carbonaceous solids present in the mixture of step a), and as a result the carbonaceous solids present in the mixture of step (a) can be obtained in step (f) in an unchanged or only slightly altered form.

[0079] According to one embodiment, the carbonaceous solids of step (f) have the same or only slightly different physical properties as the carbonaceous solids present in the mixture of step (a). According to one embodiment, the carbonaceous solids of step (f) have the same or only slightly different morphology as the carbonaceous solids present in the mixture of step (a). In the present invention, the "morphology" of the carbonaceous solids refers to the structure and / or shape of the material. The structure and / or shape of the material can be determined, for example, by scanning electron microscopy (morphology), laser diffraction (particle size), or Raman spectroscopy (structure).

[0080] According to one embodiment of the present invention, the carbonaceous solids of step f) consist of at least 80% (e.g., in the range of 80 to 99.8%), preferably at least 90%, more preferably at least 95% (e.g., in the range of 95 to 99.8%) carbon, preferably carbon black, and / or the separated carbonaceous solids of step f) are present with inorganic compounds in an amount of less than 5.0 wt.% (e.g., in the range of 0.01 to less than 5.0 wt.%), preferably less than 2.0 wt.%, more preferably less than 1.0 wt.%, based on the total weight of said separated carbonaceous solids and inorganic compounds.

[0081] According to one embodiment of the present invention, the carbonaceous solid of step f) consists of at least 80% (e.g., in the range of 80 to 99.8%), preferably at least 90%, more preferably at least 95% (e.g., in the range of 95 to 99.8%) carbon.

[0082] According to one aspect of the invention, the carbonaceous solids of step f) consist of at least 80% (e.g., in the range of 80 to 99.8%), preferably at least 90%, more preferably at least 95% (e.g., in the range of 95 to 99.8%) carbon, preferably carbon black, with less than 5.0 wt.% (e.g., in the range of 0.01 to less than 5.0 wt.%), preferably less than 2.0 wt.%, more preferably less than 1.0 wt.% inorganic compounds, based on the total weight of the separated carbonaceous solids and inorganic compounds.

[0083] According to one embodiment of the present invention, the carbonaceous solids of step f) consist of at least 80% (e.g., in the range of 80 to 99.8%), preferably at least 90%, more preferably at least 95% (e.g., in the range of 95 to 99.8%) carbon black.

[0084] According to one aspect of the invention, the carbonaceous solids of step f) consist of at least 80%, preferably at least 90% (e.g., in the range of 80 to 99.8%), more preferably at least 95% (e.g., in the range of 95 to 99.8%) carbon, preferably carbon black, with less than 5.0 wt.% (e.g., in the range of 0.01 to less than 5.0 wt.%), preferably less than 2.0 wt.%, more preferably less than 1.0 wt.% inorganic compounds, based on the total weight of the separated carbonaceous solids and inorganic compounds.

[0085] According to one aspect of the invention, the carbonaceous solids of step f) consist of at least 80% (e.g., in the range of 80 to 99.8%), preferably at least 90%, more preferably at least 95% (e.g., in the range of 95 to 99.8%) carbon, preferably carbon black, together with less than 5.0 wt. % (e.g., in the range of 0.01 to 5.0 wt. %), preferably less than 2.0 wt. %, more preferably less than 1.0 wt. %, of inorganic compounds, based on the total weight of the separated carbonaceous solids and inorganic compounds, wherein the inorganic compounds are selected from the group consisting of one or more metal sulfides, one or more metal oxides, one or more silicates, and mixtures thereof.

[0086] It is particularly preferred that the carbonaceous solid separated in step f) comprises or consists of carbon black. For example, the carbonaceous solid may consist of at least 90%, preferably at least 95% (e.g., in the range of 95 to 99.8%) of carbon black. The physical and chemical properties of carbon black are known to those skilled in the art. For example, primary particles of carbon black may have a particle size ranging from 1 to 600 nm, preferably from 10 to 300 nm. The particle size of the primary particles can be measured by laser diffraction. Primary particles of carbon black can combine to form carbon black aggregates, which may have a diameter ranging from 80 to 800 nm. These carbon black aggregates can further form higher-order structures in the form of carbon black agglomerates. Furthermore, the carbon black may have a particle size ranging from 5 to 1500 nm, as measured according to the BET method. 2 / g, preferably 15 to 600m 2 In one embodiment of the present invention, the carbonaceous solid of step f) comprises carbon black having an elemental composition of 90.0-99.7% C, 0.1-0.6% H, 0.01-0.8% S, and 0.2-3.5% O.

[0087] Any process step In addition to steps a) to f), the method of the present invention may comprise further process steps.

[0088] In step f) of the present invention, an aqueous phase is formed after separation of the carbonaceous solids. The method may comprise an additional step of post-processing the aqueous phase, thereby enabling further valuable raw materials to be obtained and / or recovered. Typically, this aqueous phase obtained in step f) contains at least the nitrogen hydrides and / or their reaction products, hydroxides, and inorganic compounds and / or their reaction products. Depending on the composition of the aqueous fluid selected, the aqueous phase obtained in step f) may also contain other substances. For environmental and / or economic reasons, it may be appropriate to separate the nitrogen hydrides and / or their reaction products, hydroxides, and inorganic compounds and / or their reaction products from the aqueous phase obtained.

[0089] According to one embodiment, the method further comprises a step g) of treating and / or recycling the aqueous phase obtained in step f).

[0090] According to one embodiment, step g) comprises the steps of: g1) separating the nitrogen hydride of step b) and / or its reaction products, and / or g2) isolating the inorganic compound(s) of step a) and / or their reaction products, and / or g3) Recovering process water.

[0091] According to one embodiment, step g) comprises the steps of: g1) separating the nitrogen hydride and / or its reaction products of step b), and g2) isolating the inorganic compound(s) and / or reaction products thereof of step a), and g3) Recovering process water.

[0092] According to one embodiment, step g) comprises the steps of: g1) separating the nitrogen hydride and / or its reaction products of step b), and g2) separating the one or more inorganic compounds of step a) and / or their reaction products from the composition obtained in step g1), and g3) recovering process water from the composition obtained in step g2).

[0093] According to another embodiment, step g) comprises the following steps: g1) separating the nitrogen hydride and / or reaction products, i.e., one or more ammonium salts; and g2) separating the one or more inorganic compounds of step a) and / or their reaction products, i.e. one or more sodium silicates, from the composition obtained in step g1), and g3) recovering process water from the composition obtained in step g2).

[0094] Steps g1), g2) and / or g3) can be carried out using techniques and equipment known to those skilled in the art.

[0095] use Another aspect of the present invention relates to the use of a nitrogen hydride as a dispersant to prepare and / or stabilize an aqueous suspension having a carbonaceous solid and at least one inorganic compound.

[0096] The term "creating and / or stabilizing an aqueous suspension" means in the present invention that a mixture of solid and liquid phases can be produced in which the solid phase can be mixed in the dispersion medium without precipitation, formation of higher order aggregates and / or sedimentation.

[0097] The present inventors have surprisingly found that nitrogen hydrides can be used to stabilize aqueous dispersions or suspensions containing mixtures having carbonaceous solids and at least one inorganic compound.

[0098] Preferred embodiments of the mixture having an aqueous fluid and a carbonaceous solid and at least one inorganic compound are described above in the description of steps a) and b) of the method of the present invention.

[0099] In one embodiment, the nitrogen hydride is used as a dispersant to form and / or stabilize an aqueous suspension having a carbonaceous solid and at least one inorganic compound, wherein the carbonaceous solid is at least 90% (e.g., in the range of 90-99.5%) carbon black, and the at least one inorganic compound refers to a plurality of inorganic compounds selected from the group consisting of one or more metal sulfides, one or more metal oxides, one or more silicates, and mixtures thereof.

[0100] In one aspect, the nitrogen hydride is used as a dispersant for preparing and / or stabilizing an aqueous suspension having a carbonaceous solid and at least one inorganic compound, wherein the carbonaceous solid is at least 90% (e.g., in the range of 90 to 99.5%) carbon black, the at least one inorganic compound refers to a plurality of inorganic compounds selected from the group consisting of one or more metal sulfides, one or more metal oxides, one or more silicates, and mixtures thereof, and the nitrogen hydride is selected from the group consisting of ammonia, inorganic ammonium salts, primary or secondary organic amines and ammonium salts thereof, and mixtures thereof, preferably from the group consisting of ammonia, ammonium hydroxide, ammonium halides, guanidine, guanidine derivatives and ammonium salts thereof, and mixtures thereof, more preferably one nitrogen hydride, ammonia, and / or ammonium hydroxide, and most preferably ammonium hydroxide.

[0101] Further Aspects In a preferred embodiment, the method for treating and / or purifying a carbonaceous solid of the present invention comprises the steps of: a) providing a mixture comprising a carbonaceous solid, preferably carbon black, and at least one inorganic compound, said mixture having the carbonaceous solid in an amount of 70 to 99 wt.%, more preferably 80 to 98 wt.%, based on the total weight of the carbonaceous solid and the at least one inorganic compound, and having the at least one inorganic compound in an amount of 1 to 30 wt.%, preferably 2 to 20 wt.%, based on the total weight of the carbonaceous solid and the at least one inorganic compound; b) providing an aqueous fluid having nitrogen hydride; c) providing an alkali hydroxide, preferably NaOH; d) contacting the mixture of step a), the fluid of step b) and the alkali metal hydroxide and / or alkali metal of step c); e) subjecting the composition obtained in step d) to an elevated temperature in the range of 80 to 240°C and a high pressure in the range of 5 to 50 bar; f) separating carbonaceous solids from the composition obtained in step e), wherein the carbonaceous solids of step f) consist of at least 80%, preferably at least 90%, more preferably at least 95% (e.g. in the range of 95-99.5%) carbon, preferably carbon black, with less than 5.0 wt.% (e.g. in the range of 0.01-5 wt.%), preferably less than 2.0 wt.%, more preferably less than 1.0 wt.% inorganic compounds, based on the total weight of the separated carbonaceous solids and inorganic compounds.

[0102] Further aspects and embodiments of the present invention are as follows:

[0103] [1] A method for treating and / or purifying carbonaceous solids, comprising the steps of: a) providing a mixture having a carbonaceous solid and at least one inorganic compound; b) providing an aqueous fluid having nitrogen hydride; c) providing an alkali and / or alkali metal hydroxide; d) contacting the mixture of step a), the fluid of step b) and the alkali metal hydroxide and / or alkali metal of step c); e) subjecting the composition obtained in step d) to reduced or elevated temperature and / or reduced or elevated pressure, f) separating the carbonaceous solids from the composition obtained in step e).

[0104] [2] the mixture of step a) has an amount of the carbonaceous solids greater than 50 wt.%, preferably greater than 70 wt.%, more preferably greater than 80 wt.%, based on the total weight of the mixture; and / or the mixture of step a) has said at least one inorganic compound in an amount of 1 to 30 wt.%, preferably 5 to 20 wt.%, relative to the total weight of said mixture; Method according to paragraph [1].

[0105] [3] The mixture of step a) is a solid mixture; and / or The method according to paragraph [1] or [2], wherein the mixture of step a) is obtained by pyrolysis of a carbonaceous material, preferably scrap tires or biomass.

[0106] [4] the carbonaceous solids consist of at least 80%, preferably at least 90%, more preferably at least 95% carbon, preferably carbon black; and / or The method according to any one of paragraphs [1] to [3], wherein the at least one inorganic compound is at least one inorganic substance and / or salt, preferably at least one inorganic substance and / or salt selected from the group consisting of one or more metal sulfides, one or more metal oxides, one or more silicates, and mixtures thereof.

[0107] [5] The fluid of step b) comprises a nitrogen hydride selected from the group consisting of ammonia, inorganic ammonium salts, primary or secondary organic amines and their ammonium salts, and mixtures thereof, preferably from the group consisting of ammonia, ammonium hydroxide, ammonium halides, guanidine, guanidine derivatives and their ammonium salts, and mixtures thereof, more preferably the nitrogen hydride is ammonia and / or ammonium hydroxide, most preferably ammonium hydroxide; and / or the fluid of step b) further comprises one or more substances selected from the group consisting of alcohols, oxidizing agents, acids, nitrates and carbonates; A method according to any of the preceding paragraphs [1] to [4].

[0108] [6] In step c), the alkali and / or alkali metal hydroxide is provided in a molar ratio relative to the inorganic compounds of the mixture of step a) ranging from 0.25:1 to 2:1, preferably from 0.5:1 to 1.5:1, more preferably from 0.75:1 to 1.25:1, and most preferably from 0.95:1 to 1.05:1; and / or In step b), the fluid is provided in an amount ranging from 2 L (fluid) / 1 kg (mixture of step a) to 200 L (fluid) / 1 kg (mixture of step a), preferably from 5 L (fluid) / 1 kg (mixture of step a) to 150 L (fluid) / 1 kg (mixture of step a), more preferably from 10 L (fluid) / 1 kg (mixture of step a) to 100 L (fluid) / 1 kg (mixture of step a); A method according to one of the preceding paragraphs [1] to [5].

[0109] [7] In step e), the composition is subjected to a temperature of −35° C. to 400° C., preferably 25° C. to 300° C., more preferably 80° C. to 240° C.; and / or In step e), the composition is subjected to a pressure of 0.001 to 200 bar, preferably 1 to 100 bar, more preferably 5 to 50 bar; and / or In step e), the pH of the composition is adjusted to a value between 0 and 14, preferably between 7 and 14, more preferably between 9 and 13; A method according to one of the preceding paragraphs [1] to [6].

[0110] [8] step e) is carried out stepwise under at least two different conditions with respect to temperature, pressure and / or pH, preferably under at least two different conditions with respect to temperature and pressure; and / or step f) comprises filtering the carbonaceous solids; A method according to one of the preceding paragraphs [1] to [7].

[0111] [9] the carbonaceous solid of step f) consists of at least 80%, preferably at least 90%, more preferably at least 95% carbon, preferably carbon black; and / or the separated carbonaceous solids of step f) are present with less than 5.0 wt.%, preferably less than 2.0 wt.%, more preferably less than 1.0 wt.%, of inorganic compounds, based on the total weight of the separated carbonaceous solids and the inorganic compounds; A method according to one of the preceding paragraphs [1] to [8].

[0112]

[10] Use of a nitrogen hydride as a dispersant for preparing and / or stabilizing an aqueous suspension having a carbonaceous solid and at least one inorganic compound. [Example]

[0113] The present invention is further described by the following examples: [Table 1]

[0114] The mixture of step a) was a mixture obtained by pyrolysis of scrap tires.

Claims

1. 1. A method for treating and / or purifying carbonaceous solids, comprising the steps of: a) providing a mixture having a carbonaceous solid and an inorganic compound; the carbonaceous solids consist of at least 90% carbon black; the inorganic compound comprises zinc sulfide, zinc oxide, silicon dioxide, silicates, aluminum oxide, or a mixture thereof; the mixture having greater than 50 wt. % carbonaceous solids based on the total weight of the mixture; b) providing an aqueous fluid having nitrogen hydride; c) providing an alkali metal hydroxide and / or an alkali metal; d) contacting the mixture of step a), the fluid of step b), and the alkali metal hydroxide and / or alkali metal of step c); e) subjecting the composition obtained in step d) to a temperature greater than 20°C and / or a pressure greater than 1.013 bar; f) separating carbonaceous solids from the composition obtained in step e), said separated carbonaceous solids comprising carbon black.

2. 10. The method of claim 1, wherein the mixture of step a) has greater than 70 wt.% of the carbonaceous solids, based on the total weight of the mixture of step a).

3. 3. The method according to claim 1 or 2, wherein the mixture of step a) is obtained by pyrolysis of scrap tires.

4. 4. The method of claim 1, wherein the fluid in step b) comprises a nitrogen hydride selected from the group consisting of ammonia, inorganic ammonium salts, primary or secondary organic amines and their ammonium salts, and mixtures thereof.

5. A method according to any one of claims 1 to 3, wherein the nitrogen hydride is ammonia and / or ammonium hydroxide.

6. 6. The method according to any one of claims 1 to 5, wherein the alkali metal hydroxide and / or alkali metal provided in step c) is NaOH, KOH or a mixture thereof.

7. The aqueous fluid provided in step b) comprises ammonium hydroxide; The alkali metal hydroxide and / or alkali metal provided in step c) is NaOH, KOH or a mixture thereof; The method according to any one of claims 1 to 3.

8. 8. The method according to any one of claims 1 to 7, wherein in step e) the composition is subjected to a temperature of from 50°C to 400°C and a pressure of from 2 to 200 bar.

9. 9. The method of claim 8, wherein in step e) the composition is subjected to a temperature of from 80° C. to 240° C. and a pressure of from 5 to 50 bar.

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