Method for producing recovered carbon black

Abstract

The invention relates to a method for producing recovered carbon black, comprising the following steps: • selecting used tires, • comminuting the used tires to form a used tire granulate • pyrolyzing the used tire granulate with a residence time between 2 and 4 hours at a material temperature between 550°C and 750°C • grinding the recovered carbon black • wet-pelletizing the ground recovered carbon black. The recovered carbon black produced by the method is particularly suitable for use in rubber applications, for example for producing tires.

Description

[0001] Pyrum Innovations AG 24038-P-WO / 11 / 25 / 2025

[0002] 1

[0003] DESCRIPTION

[0004] Process for the production of recovered industrial carbon black

[0005] The present invention relates to a method for producing recovered industrial carbon black.

[0006] The recycling of waste and residual materials is gaining increasing importance due to the growing scarcity and associated price increases of raw materials, especially fossil fuels. The development of new energy sources and processes, particularly renewable energies, is receiving increasing attention and support. Pyrolysis technology, specifically the pyrolytic recycling of petroleum products such as tires, is attracting growing interest.

[0007] The production of tires, pigments, and paints requires modified carbon with a high surface-to-volume ratio. This industrial carbon black is an organic raw material produced by the controlled combustion of gaseous or liquid raw materials from the petroleum, natural gas, or coal industries. Aromatic compounds with a high carbon-to-hydrogen ratio are used in this process.

[0008] There are two main methods for producing conventional industrial carbon black (virgin carbon black (vCB)), which differ in the type of heat input: partial oxidation and external heat input. In partial oxidation, a portion of the raw material is burned with controlled airflow to generate the heat required for temperatures between 1,200 °C and 1,900 °C. The resulting product is then cooled and dried. In external heat input, the necessary heat is supplied from an external source.

[0009] The most frequently used process is the furnace carbon black process. This process utilizes highly aromatic, viscous residues from oil refineries, coking plants, or catalytic cracking plants as feedstock. It follows the principles of partial oxidation. The required high temperatures are generated in the combustion chamber by burning natural gas or oil. Subsequently, the highly aromatic residues are... [Pyrum Innovations AG 24038-P-WO / 25.11.2025]

[0010] 2

[0011] Carbon black is sprayed into the hot gas. The incomplete combustion and the parallel pyrolysis process produce industrial carbon black along with hydrogen and other gases. After a defined reaction time in the combustion chamber, the gas mixture is cooled and separated from the remaining process gas by a filter system.

[0012] A disadvantage of these manufacturing methods is that they are very energy-intensive and produce high CO2 emissions. Therefore, there is great interest in the reuse of industrial carbon black.

[0013] In particular, recovered carbon black (rCB) (ASTM D8178) from used tires is a promising technology for returning tire components to the recycling loop and thus increasing the circularity of the tire.

[0014] Current recycling methods are mostly limited to energy recovery, releasing significant amounts of CO2 through the complete combustion of the tire's carbon-containing components. Used tire pyrolysis allows for the reuse of individual components, including in new tires, and emits significantly less CO2 due to its low-oxygen combustion. In particular, the pyrolysis gases and oils produced during pyrolysis can be used for energy generation or as feedstock in the chemical industry. This offers significant advantages in terms of overall sustainability compared to previously used technologies such as the production of carbon black from energy-intensive furnace processes.

[0015] The use of rCB depends on selected raw materials and specific pyrolysis conditions. Carbon black is a widely used filler in rubber compounds because it significantly improves the strength of vulcanized rubber compared to rubber without filler. Several grades of carbon black are used in the rubber industry, including N-220, N-330, N-550, and N-660 according to ASTM D1765-14. rCB is intended as a sustainable alternative to reinforcing filler for rubber compounds in tire applications, including the N300-N900 series (ASTM D1765). Potential applications therefore include, for example, the inner layer, sidewall, tread surface, and substructure of various specialized tire components.

[0016] Pyrolysis processes and pyrolysis devices for the production of recovered industrial carbon black are known from the prior art.

[0017] From WO 2010 / 127664 A1, a multi-stage, energy-autonomous and continuously Pyrum Innovations AG 24038-P-WO / 25.11.2025

[0018] A pyrolysis process for the fractional recovery of valuable materials and energy from free-flowing, highly cross-linked organic compounds, in particular from waste tires, sealing profiles, and other plastic granules, as well as an apparatus for carrying out the process, are known. To develop an energy-autonomous, continuously operating pyrolysis process for free-flowing organic granules, it is proposed that the granules pass gravimetrically from top to bottom through a vertical, multi-stage pyrolysis reactor, where they are heated to process temperatures adjustable in stages, ranging from 300 to 1,200 °C, and pyrolyzed. Subsequent fractional condensation of the pyrolysis vapors results in the recovery of oil and gas compounds, and downstream use of the pyrolysis gas in a motor generates the energy required for the pyrolysis process.

[0019] WO 2012 / 092924 A1 describes a thermal reactor for the continuous thermolytic recycling of waste tires, vulcanization residues, and waste plastic granules, and similar products. The thermal reactor has an inlet section, a heating zone middle section, and an outlet section, arranged vertically one above the other. A suction pipe is centrally located in the heating zone middle section of the thermal reactor. The surface of this pipe has numerous bores and / or slots for venting the resulting short-chain hydrocarbon vapors. Conical bells are mounted one above the other on the suction pipe. The outer shell of the heating zone middle section has a multitude of radially arranged heating plates, offset from each other in the stacked heating levels.

[0020] WO 2011 / 035812 A1 relates to a multi-stage thermal treatment of rubber waste, in particular used tires. The process comprises several steps in which a product granulate made from rubber waste is transferred to three different, successive heating zones of a reactor. In the heating zones, the product granulate is first heated to a temperature between 100° and 200°C, preferably 150° to 180°C, then to a second temperature between 200° and 350°C, and finally to a third temperature between 300° and 600°C. The temperature is maintained until no further oil is released in the respective heating zone. As a final step, the product granulate is removed from the reactor and the desired solid materials are separated. Pyrum Innovations AG 24038-P-WO / 25.11.2025

[0021] 4

[0022] EP 3 627 050 B1 describes a pyrolysis plant with a pyrolysis reactor having an upper reactor screw and a lower reactor screw.

[0023] A pyrolysis process for recycling used tires is known from US patent 2016 / 0307169 A1.

[0024] WO 2013 / 095145 A1 concerns a process for recycling waste rubber, which includes the steps of pyrolyzing waste rubber in a two-stage process to obtain a carbon material, and the subsequent grinding of the carbon material thus obtained.

[0025] WO 2020 / 020810 A1 discloses a filler comprising recovered carbon black with an iodine adsorption number, measured according to ASTM D-1510-17, between 95 g / kg and 160 g / kg, preferably between 115 g / kg and 140 g / kg.

[0026] WO 2020 / 082050 A1 describes a process for converting tires into pelletized, recovered carbon black, comprising the following process steps: cutting a set of tires into a volume of tire rubber segments, wherein the set of tires is selected from a group comprising an agricultural tire, a commercial vehicle tire, and a passenger car tire; thermally depolymerizing the volume of tire rubber segments in a pyrolytic reactor to a volume of carbon-containing material; comminuting the volume of carbon-containing material; removing agglomerates larger than the maximum agglomerate diameter from the volume of carbon-containing material; mixing the volume of carbon-containing material with a binder in a mixer over a first period, wherein the mixer induces the formation of a set of pellets with different pellet diameters;Drying the batch of pellets in a dryer to a specific moisture content; and removing an initial portion of pellets larger than a maximum pellet size from the batch of pellets.

[0027] CN 213012686 U discloses a device for splitting carbon black from scrap tires, comprising a cracking furnace and a heat treatment furnace. The cracking furnace consists of an inner and an outer furnace drum, the outer drum surrounding the inner drum. A material inlet is located at one end of the inner drum, and a [Pyrum Innovations AG 24038-P-WO / 25.11.2025] is located at the other end of the outer drum.

[0028] 5

[0029] Material outlet. At the other end of the housing, a gas-phase lysate outlet and a solid-phase lysate outlet are provided.

[0030] CN 107236329 A concerns a process for producing carbon black from waste tires and refers to a process for using waste tires.The process for producing carbon black from scrap tires comprises the following steps: classification of the scrap tires and bead cutting; feeding the treated tires into a crusher, multi-stage shredding to obtain granules, and recovery of the dust generated during the shredding process using dust removal equipment; feeding the granulated scrap tire raw materials and the recovered dust into a magnetic separator and removing iron impurities to obtain pure rubber blocks after iron removal; grinding the pure rubber blocks in a grinding machine, carrying out a reaction in a pyrolysis furnace, and recovering the carbon residues produced during pyrolysis; and carrying out magnetic separation of the carbon residues produced during pyrolysis, removing iron-containing steel wire remnants, and grinding the recovered raw carbon residues.

[0031] A process for recycling used tires is known from US Patent 2022 / 0251392 A1. The process includes, among other things, the following pyrolysis steps: feeding the shredded material into a rotating horizontal cylindrical thermolysis reactor surrounded by an outer chamber; closing the reactor and introducing an inert gas to create an oxygen-free atmosphere; indirect heating of the reactor with gases from a combustion chamber by directing the gases into the outer chamber; gradual increase of the temperature from room temperature and maintenance in a range between 250°C and 350°C for a period of 1 to 4 hours, during which the water, all lighter hydrocarbons, and some of the heavier hydrocarbons are gasified; and a further increase of the temperature to over 450°C for a period of 2 to 4 hours to achieve the gasification of the heavier hydrocarbons that are still in the liquid state.

[0032] German patent DE 102021 205 776 A1 relates to a process for producing carbon black from waste. The process comprises the following steps: providing the waste, optionally preheating the waste to a temperature of 50 to 200°C, pyrolysis of the waste using microwaves and in the absence of oxygen, resulting in carbon black as a product, and cooling the carbon black by passing a reaction gas over the waste or the carbon black. Pyrum Innovations AG 24038-P-WO / 25.11.2025

[0033] 6

[0034] EP 4 043 536 A1 describes a device and a method for wet carbon black processing. The device comprises a water tank for the direct collection of carbon black material from a pyrolysis reactor into a water bath, resulting in a wet, carbon black-containing material. The device further comprises at least one wet grinding stage configured to reduce the average particle size of the carbon black particles in the wet, carbon black-containing material. The wet, carbon black-containing material is then dewatered in a dewatering module.

[0035] A disadvantage of these known processes is that the produced recycled carbon black (rCB) exhibits poor reinforcing properties, particularly when used in rubber compounds. This is due to the often unsorted tire raw material from various sources, which differ in aging and composition. Furthermore, the current state of the art regarding pyrolysis involves the production of carbon black in two-stage rotary kilns or expensive and technically demanding screw reactors, which often require high temperatures and long reaction times. These processing problems also result in a high ash content (inorganic and especially organic) and thus a low carbon content, further limiting the performance of the recovered industrial carbon black for use in tires. The following problems therefore exist in the product:

[0036] • Particle sizes above 11 pm due to inadequate grinding technology,

[0037] • Heterogeneous primary particle distribution due to unsorted tire raw material,

[0038] • Excessively high and fluctuating proportion of inorganic components (ash) due to unsorted tire raw material with a high silicate content,

[0039] • Low and fluctuating toluene transmission due to insufficient and uneven pyrolysis reaction,

[0040] • High levels of volatile components due to insufficient and uneven reaction,

[0041] • High proportion of polycyclic aromatic hydrocarbons (PAHs) due to insufficient and uneven reaction.

[0042] The invention is based on the objective of providing an optimized recovered carbon black and a process for its production. It is also an objective of the invention to provide recovered carbon black as a raw material for tire manufacturing. In particular, it is an objective of the invention to provide recovered carbon black with similar reinforcing properties to those of Pyrum Innovations AG 24038-P-WO / 25.11.2025

[0043] 7

[0044] To provide industrial carbon blacks of types N772 - N660 and N660 - N550 for tire manufacturing.

[0045] The task is solved using a procedure with the following steps:

[0046] • Selection of used tires,

[0047] • Shredding of used tires into used tire granules,

[0048] • Pyrolysis of the waste tire granulate with a residence time of 2 to 4 hours at a material temperature between 550°C and 750°C,

[0049] • Grinding of the recovered industrial carbon black using a counter-jet mill or an impact classifier mill,

[0050] • Wet pelletizing of the ground, recovered industrial carbon black.

[0051] Various reactor types can be used for pyrolysis. These different reactor types have advantages and disadvantages in terms of energy efficiency, temperature stability, miscibility, and particle, pyrolysis oil, and gas properties. Possible reactor types include, for example, fixed-bed, (mechanically) mixed-bed (auger-type, moving screw), and fluidized-bed reactors. A pyrolysis reactor can also be a vertical moving-bed reactor with several pyrolysis zones arranged one above the other. This type of reactor may incorporate means for indirect electrical heating of the inner tube and a slot system on the outer surface of the internal components to extract pyrolysis vapors by negative pressure. The pyrolysis of waste tires produces gaseous products (pyrolysis gas), liquid products or products that condense after pyrolysis (pyrolysis oil), and solid products (pyrolysis coke).Pyrolysis coke is the recovered industrial soot with its organic and inorganic residues.

[0052] In addition to conventional parameters such as reaction time, heating rate, and reaction temperature, the particle size of rCB can be influenced by "fast" and "flash" pyrolysis processes. After pyrolysis, the recovered industrial carbon black can be further processed for use in rubber applications by mechanical and / or chemical post-treatment and pelletizing. The type of post-treatment depends on the specific rubber application. Properties similar to those of conventional industrial carbon blacks (virgin carbon black (vCB)) of types N300 to N772 are preferred in rubber compounds for tire applications. Preferably, the properties of rCB are similar to those of type N660. Particularly preferably, the properties of rCB are similar to those of type N550. Pyrum Innovations AG 24038-P-WO / 25.11.2025

[0053] 8

[0054] The used tires can be, for example, truck tires, car tires, or a mixture thereof. The tires can be sorted by type. Used tire granulate is produced from the tires. This granulate is produced using a granulating and separating plant in which whole or pre-cut tires are processed into rubber granulate separated from textiles and steel. The production of the used tire granulate can be carried out, for example, using an Eldan tire line type E5000T and a steel cleaning system type IL4000S. The rubber granulate preferably has a purity of >99.5% (ASTM D8268) and a particle size of 0.5–6.0 mm (ASTM D5644). Recovered carbon black can be obtained from pyrolysis with a residence time of 2 to 4 hours at a material temperature between 550°C and 750°C. After grinding, it can be wet pelletized (Lödige, CoriMix type CM 80 or Mars Minerals, type 26D100U-SS).

[0055] The recovered industrial carbon black produced according to the inventive process has, among other things, the following advantages:

[0056] • Improvement of the properties in the rubber compound (Ref. N550 / N660 (ASTM D1765)),

[0057] • Defined particle sizes through controlled grinding,

[0058] • More homogeneous primary particle distribution due to the defined tire raw material,

[0059] • Defined and constant proportion of inorganic and organic components (ash) based on a defined tire raw material,

[0060] • High and constant toluene transmission due to optimal and homogeneous reaction,

[0061] • Low and constant levels of volatile components due to optimal and homogeneous reaction,

[0062] • Low PAHs due to optimal and homogeneous reaction.

[0063] Advantageously, the recovered industrial carbon black from the process according to the invention can be used for pigment applications in color pastes, printing inks, plastics, varnishes, coatings, rubber and tire applications, in road construction or for steel production.

[0064] The recovered carbon black can be ground using a counterjet mill, in particular a jet mill (Hosokawa type 100 AFG or type 800 TDG). Alternatively, the recovered carbon black can be ground in an impact classifier mill. Pyrum Innovations AG 24038-P-WO / 25.11.2025

[0065] 9

[0066] A preferred embodiment of the invention consists in the pyrolysis taking place in a single-stage vertical moving bed reactor.

[0067] The single-stage vertical moving-bed reactor can, for example, be a thermal reactor with an inlet section, a heating zone middle section, and an outlet section, all arranged vertically one above the other. A suction pipe is centrally located within the heating zone middle section of the thermal reactor. The surface of this pipe has numerous bores and / or slots for venting the resulting short-chain hydrocarbon vapors. Conical bells are mounted one above the other onto the suction pipe. The outer shell of the heating zone middle section features a multitude of radially arranged heating plates, offset from each other in relation to the stacked heating levels.

[0068] Advantageously, the use of rCB after a single-stage diffusion sedimentation-driven pyrolysis process under temperature and reaction time control allows for the minimization of the organic residue in particular, which, together with the coke residues, significantly influences the reinforcing properties, for example in rubber applications.

[0069] A preferred embodiment of the invention consists in the waste tires being a mixture of sorted truck waste tires and sorted passenger car waste tires in a ratio of 60:40 (w / w%), wherein the pyrolysis of the waste tire granulate takes place with a residence time of 2 to 3 hours at a material temperature of 650°C and 750°C.

[0070] A particularly preferred embodiment of the invention consists in the waste tires being sorted truck waste tires, wherein the pyrolysis of the waste tire granulate takes place with a residence time of 3 to 4 hours at a material temperature of 550°C and 650°C.

[0071] Furthermore, the recovered industrial carbon black produced by the inventive process belongs to the invention.

[0072] The recovered industrial carbon black preferably has a particle size between 8 and 10 pm according to ASTM WK87480.

[0073] The invention is described in more detail below using two exemplary embodiments. Pyrum Innovations AG 24038-P-WO / 25.11.2025

[0074] 10 rCB Type 1

[0075] Industrial carbon black type 1 is produced using a vertical moving bed reactor according to the Pyrum design (WO 2010 / 127664 A1 , WO 2012 / 092924 A1) by using a granulate mixture with a purity >99.5% (ASTM D8268) and a grain size of 0.5 - 6.0 mm (ASTM D5644) from sorted truck tires (solid tires) and sorted passenger car tires (solid tires) in a ratio of 60:40 (w / w%) for a residence time of 2 to 3 hours at a material temperature of 650°C to 750°C. The raw rCB is then milled using a counterjet mill (Hosokawa Type 100 AFG and / or Hosokawa Type 800 TDG) and the powder is wet pelletized (Lödige, CoriMix Type CM 80 and / or Mars Minerals, Type 26D100U-SS). Advantageously, the in-rubber performance of rCB Type 1 is comparable to that of vCB Type N660. In particular, rCB Type 1 exhibits in-rubber performance with properties intermediate between those of vCB Types N772 and N660. rCB Type 2

[0076] Using a vertical moving bed reactor of the Pyrum design (WO 2010 / 127664 A1, WO 2012 / 092924 A1), raw rCB type 2 is produced by employing pure, recycled truck tire granulate (solid tires) with a purity >99.5% (ASTM D8268) and a particle size of 0.5–6.0 mm (ASTM D5644) for a residence time of 3 to 4 hours at a material temperature of 550°C to 650°C. The raw rCB is then milled using a jet mill (Hosokawa type 100 AFG or type 800 TDG) and the powder is wet pelletized (Lödige, CoriMix type CM 80 or Mars Minerals, type 26D100U-SS). Advantageously, the in-rubber performance of the rCB Type 2 is comparable to that of the vCB Type N550. In particular, the rCB Type 2 exhibits in-rubber performance with characteristics intermediate between those of the vCB Types N660 and N550.

[0077] Pyrum Innovations AG 24038-P-WO / 11 / 25 / 2025

[0078] 11

[0079] Table 1: Physicochemical properties of rCB Basic, rCB Type 1 & rCB Type 2:

[0080] Reclaimed carbon black of types rCB Type 1 and rCB Type 2 can be described based on the properties of the rubber compound mixed with the rCB, particularly for tire manufacturing. The properties of the types rCB are described in Pyrum Innovations AG 24038-P-WO / 25.11.2025.

[0081] 12

[0082] Basic, rCB Type 1 and rCB Type 2 were compared with the state-of-the-art industrial carbon black types vCB N660 and vCB N550. rCB Basic is the recovered industrial carbon black as previously obtained using the Pyrum process (WO 2010 / 127664 A1, WO 2012 / 092924 A1).

[0083] The comparison is made with the properties of the rubber compound according to ASTM D36, DIN3191 (SSBR)

[0084] Pyrum Innovations AG 24038-P-WO / 11 / 25 / 2025

[0085] 13

[0086] Table 2: Properties of the rubber compound of types rCB Basic, rCB Type 1, rCB Type 2

[0087] *1 measured at

[0088] Room temperature (RT)

[0089] *2 Maximum (smaller = better)

[0090] *3 Classification of industrial carbon blacks according to ASTM D1765

Claims

Pyrum Innovations AG 24038-P-WO / 11 / 25 / 2025 14 REQUIREMENTS 1. A process for producing recovered industrial carbon black comprising the following steps: • Selecting used tires, • Shredding of used tires into used tire granules, • Pyrolysis of the waste tire granulate with a residence time between 2 and 4 hours at a material temperature between 550°C and 750°C, • Grinding of the recovered industrial carbon black using a counter-jet mill or an impact classifier mill, • Wet pelletizing of the ground, recovered industrial carbon black.

2. Method according to claim 1, characterized in that the pyrolysis takes place in a single-stage vertical moving bed reactor.

3. Method according to claim 1 or 2, characterized in that the waste tires are a mixture of sorted truck waste tires and sorted passenger car waste tires in a ratio of 60:40 (w / w%), wherein the pyrolysis of the waste tire granulate takes place with a residence time of 2 to 3 hours at a material temperature of 650°C and 750°C.

4. Method according to claim 1 or 2, characterized in that the waste tires are sorted truck waste tires, wherein the pyrolysis of the waste tire granulate takes place with a residence time of 3 to 4 hours at a material temperature of 550°C and 650°C.

5. Recovered industrial carbon black from a process according to any of the preceding claims.

6. Recovered industrial carbon black according to claim 5, characterized in that the particle size according to ASTM WK87480 is between 8 and 10 pm.

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