PROCESS FOR THE PRODUCTION OF A PRECIPITATED SILICA CONTAINING MANGANESE FROM VEGETABLE ASH, PRECIPITATED SILICA AND ITS USE IN TIRE APPLICATIONS

Abstract

The invention relates to a process for producing a precipitated silica from a plant ash, wherein said precipitated silica contains SiO2 in particulate form and manganese. The plant ash is directly employed in the process, preferably without being subjected to any pre- treatment such as washing and / or incinerating. The invention further concerns a precipitated silica (obtainable by the above process) containing SiO2 in particulate form and manganese and its use for the manufacture of a filled elastomeric composition, a tire part and / or a tire.

Description

1 / 63 “PROCESS FOR THE PRODUCTION OF A PRECIPITATED SILICA CONTAINING MANGANESE FROM VEGETABLE ASH, PRECIPITATED SILICA AND ITS USE IN TIRE APPLICATIONS” CROSS-REFERENCE TO RELATED REQUESTS

[0001] This application claims priority over European applications No. 23305439.4 and No. 23305440.2, both filed on 29 March 2023, and over European applications No. 23185252.6 and No. 23185224.5, both filed on 13 July 2023, the full content of which is incorporated herein by reference for all purposes. FIELD OF TECHNIQUE

[0002] The invention relates to a process for producing precipitated silica from vegetable ash. The process comprises the alkaline digestion of said vegetable ash to obtain a silicate solution, which in turn is reacted with an acidifying agent to achieve the precipitation of SiO2. The process is characterized by the vegetable ash being directly subjected to alkaline digestion, preferably without being subjected to any pretreatment, such as washing and / or incineration. The invention also relates to precipitated silica, preferably obtainable or obtained by said process. The invention further relates to the use of precipitated silica, preferably obtainable or obtained by said process, for the manufacture of a filled elastomeric composition, a tire part and / or a tire. BACKGROUND OF THE TECHNIQUE

[0003] Silicon dioxide (SiO2), also known as silica, is a silicon compound that is commonly found in nature. Naturally occurring silica exists in both amorphous and crystalline forms, such as cristobalite, tridymite, and quartz, the latter being the main constituent of sand.

[0004] Quartz sand is frequently used for the production of silicates, in particular sodium silicates, which can be obtained, Petition 870250080266, dated 08 / 09 / 2025, page 11 / 358 2 / 63 for example, by hydrothermal treatment of quartz sand with strong bases, such as sodium hydroxide, or by fusing quartz sand with sodium carbonate at high temperatures of around 1400-1500 °C.

[0005] Sodium silicates can be used in their original form or can be employed as raw materials for the preparation of various inorganic materials, notably silica gel and precipitated silica. Precipitated silica is a form of synthetic silica in amorphous form.

[0006] Silicates and precipitated silica are highly versatile materials with a variety of applications in diverse technological fields, from construction to detergents, tires, adhesives, food and pharmaceutical industries, and their global demand is constantly increasing.

[0007] However, the processes mentioned above for producing precipitated silica have the main disadvantages of the fact that sand, used as raw material, is not a renewable resource in human timescales, since its replenishment occurs through erosion or weathering processes of rocks over geological time.

[0008] Furthermore, the conventional process mentioned above for manufacturing silica by melting sand requires high energy consumption because this process requires the reagents to be heated to high temperatures.

[0009] Thus, it seems evident that there remains a need to find a process for producing precipitated silica that is not only more environmentally sustainable, but also cost-effective.

[0010] A possible renewable source can be envisioned in ashes derived from the combustion of plants or plant parts and, in particular, plant ashes derived from the combustion of plants rich in silica. In this respect, a particularly rich biogenic source of silica is composed of ashes derived from rice husks. Petition 870250080266, dated 08 / 09 / 2025, page 12 / 358 3 / 63

[0011] Rice husk is an agricultural residue from the rice milling industry and is abundant in rice-producing countries. After burning, about 20% of the weight of the rice husk is converted into ash, which comprises up to 97% silica by weight.

[0012] Given the high amount of silica contained in these ashes and their intrinsically renewable nature, many efforts have been made to try to extract silica from them, as this could represent an economically viable option for obtaining precipitated silica, which could also address the issue of proper disposal of rice husk (which, as mentioned earlier, is a waste material from the milling industry).

[0013] However, one of the critical aspects of employing vegetable ash, and in particular rice husk ash (RHA), as a starting material relates to the complex nature and variable composition of said ash, which, in addition to SiO2, generally includes other elements such as carbon, K, Mn, P, S, etc. Since, for a multitude of applications, a high-purity precipitated silica is often desired, many efforts have been made to try to purify said ash in order to reduce the content of the aforementioned elements before alkaline digestion of the ash.

[0014] Document WO2019 / 168690 describes a process for the preparation of silicate from RHA. In this process, clean water is used to remove impurities contained in rice husk ash to a level of < 250 ppm (of S and Cl) before alkaline digestion of said ash in order to obtain a high-purity silicate.

[0015] The main disadvantage of this type of process is that the washing stages use very large quantities of water, which could be used for other needs. This fact has a negative impact not only on the overall costs and complexity of the process, but also on the environment, as it contributes to the scarcity of resources on the planet. Petition 870250080266, dated 08 / 09 / 2025, page 13 / 358 4 / 63

[0016] Document IN2020 / 21056035 discloses a process for preparing precipitated silica from RHA, whereby RHA is incinerated (burned again) at a temperature of 900 °C to 1025 °C before alkaline digestion of the ashes to remove moisture, carbon and any other volatile material to achieve precipitated silica with high purity.

[0017] Furthermore, in this case, such pre-treatment of the ashes requires energy and is disadvantageous for the economy and the ecological and process impacts.

[0018] Therefore, there was still a need to develop an innovative process to produce precipitated silica that is easy, environmentally friendly and cost-effective. SUMMARY OF THE INVENTION

[0019] The present invention relates to a process for producing precipitated silica from vegetable ash, wherein said process comprises the steps of: (I) reacting a vegetable ash containing SiO2 and manganese in a weight amount, expressed as elemental manganese, of at least 10 ppm, based on the weight of SiO2 contained in the vegetable ash, with an alkali metal base, preferably an alkali metal hydroxide, at a temperature of at least 100 °C in an aqueous reaction medium, so as to obtain an aqueous silicate solution comprising (i) SiO2 in the form of silicate anions and (ii) manganese in a weight amount, expressed as elemental manganese, of at least 10 ppm, based on the weight of SiO2 contained in the silicate solution, and (II) react the aqueous silicate solution with an acidifying agent at a temperature of at least 40 °C in an aqueous reaction medium having a pH exceeding 7.0 during at least part of the reaction duration, so as to achieve precipitation of SiO2 and produce a Petition 870250080266, dated 09 / 08 / 2025, p. 14 / 358 5 / 63 aqueous fluid paste comprising particulate SiO2 and manganese in a weight amount, expressed as elemental manganese, of at least 10 ppm, based on the weight of SO2 contained in the aqueous fluid paste.

[0020] The process according to the invention optionally and additionally comprises a step (A), prior to step (I), of burning a plant and / or a part of a plant containing SiO2 and manganese in a weight quantity, expressed as elemental manganese, of at least 10 ppm, based on the weight of SiO2 contained in the plant and / or part of a plant, in order to obtain vegetable ash. According to one embodiment, the process according to the invention comprises said step (A).

[0021] According to one embodiment, the plant part and / or plant, vegetable ash, aqueous silicate solution and aqueous fluid paste additionally contain phosphorus in a weight amount, expressed as elemental phosphorus, of at least 10 ppm, based on the weight of SiO2 contained, respectively, in the plant part and / or plant, vegetable ash, aqueous silicate solution and aqueous fluid paste.

[0022] The process of the present invention may comprise step (A) and be free of any step (B) comprising reburning of vegetable ash, wherein said step (B) is after step (A) and before step (I).

[0023] The process of the present invention may comprise step (A) and be free of any step (B) comprising washing vegetable ash with a liquid containing water or acidified water, said step (B) occurring after step (A) and before step (I). It may also comprise step (A) and be free of any step (B) comprising acid leaching and / or acid wetting of vegetable ash, said step (B) occurring after step (A) and before step (I). It may also comprise step (A) and be free of any step (B) comprising at least one of (i) washing vegetable ash with a liquid containing water or acidified water and (ii) acid leaching and / or acid wetting of vegetable ash, said step (B) occurring after step (A) and before step (I). Petition 870250080266, dated 08 / 09 / 2025, page 15 / 358 6 / 63 that said step (B) occurs after step (A) and before step (I). Washing vegetable ash with a liquid containing water or acidified water, acid leaching of vegetable ash and acid wetting of vegetable ash are operations that would otherwise generally result in a partial or complete removal of manganese and / or phosphorus (when present) from the vegetable ash.

[0024] According to a particularly preferred embodiment, the process of the present invention comprises step (A) and is free from any step (B) of removing part or all of the manganese and / or phosphorus (where present) from vegetable ash, wherein said step (B) is after step (A) and before step (I).

[0025] The process of the present invention may comprise step (A) and be free of any step (B') comprising washing the plant and / or part of the plant with a liquid containing water or acidified water, wherein said step (B') is before step (A). It may comprise step (A) and be free of any step (B') comprising acid leaching and / or acid wetting of the plant and / or part of the plant, wherein said step (B') is before step (A). The same may comprise step (A) and be free of any step (B') comprising at least one of (i) washing the plant and / or part of the plant with a liquid containing water or acidified water and (ii) acid leaching and / or acid wetting of the plant and / or part of the plant, wherein said step (B') occurs before step (A) and before step (I).Washing the plant and / or plant part with a liquid containing water or acidified water, acid leaching of the plant and / or plant part, and acid wetting of the plant and / or plant part would otherwise and generally result in a partial or total removal of manganese and / or potassium (when present) from the plant and / or plant part.

[0026] According to another embodiment, the process of the present invention may also be free of any step (B') of removing part or all of the manganese and / or phosphorus (where present) from the plant and / or part of the plant, wherein said step (B') is before step (A). Petition 870250080266, dated 09 / 08 / 2025, p. 16 / 358 7 / 63

[0027] According to a further preferred embodiment, the process of the present invention (i) comprises step (A), (ii) is free of any step (B) of removing some or all of the manganese and / or phosphorus (where present) from the vegetable ash, and (iii) is free of any step (B') of removing some or all of the manganese and / or phosphorus (where present) from the plant and / or part of the plant, wherein said step (B) is after step (A) and before step (i) and wherein said step (B') is before step (A).

[0028] According to another embodiment, the invention process further comprises the steps of: (III) filter the aqueous fluid paste obtained after step (II), preferably using a filter press, in order to obtain a filter cake comprising particulate SiO2; (IV) optionally, wash the filter cake with a liquid containing water; (V) liquefy the filter cake into a fluidizable aqueous suspension comprising particulate SiO2 by adding a liquid containing water to the filter cake and, optionally and additionally, subjecting the filter cake to mechanical and / or chemical treatment; (VI) dry the fluidizable aqueous suspension, preferably by means of a spray dryer, in order to obtain precipitated silica.

[0029] The invention process is advantageously free of any step (B”), after step (VI), which comprises washing the precipitated silica with a liquid containing water or acidified water. The invention process is also advantageously free of any step (B”), after step (VI), which comprises performing acid leaching of the precipitated silica and / or performing acid wetting of the precipitated silica. Washing the precipitated silica with a liquid containing water or acidified water, acid leaching of the precipitated silica and acid wetting, the precipitated silica would otherwise generally result in a partial or complete removal of manganese and / or phosphorus (where present) from the precipitated silica. Petition 870250080266, dated 08 / 09 / 2025, page 17 / 358 8 / 63

[0030] Preferably, the process of the invention is free of any step (B''), after step (VI), of removing part or all of the manganese and / or phosphorus (where present) from the precipitated silica.

[0031] Furthermore, the invention also relates to a precipitated silica containing particulate SiO2 and manganese in an amount by weight, expressed as elemental manganese, ranging from 10 ppm to 75 ppm, based on the weight of SiO2 contained in the precipitated silica. Preferably, said precipitated silica additionally contains phosphorus in an amount by weight, expressed as elemental phosphorus, of at least 10 ppm, based on the weight of SiO2 contained in the precipitated silica. According to a preferred embodiment, said precipitated silica is obtainable or obtained according to the process of the present invention.

[0032] In addition, the invention relates to the use of precipitated silica for the manufacture of at least one of (i) an elastomeric composition filled with precipitated silica, (ii) a tire part comprising (possibly composed of) an elastomeric composition filled with precipitated silica, and (iii) a tire comprising at least one part comprising (possibly composed of) an elastomeric composition loaded with precipitated silica containing particulate SiO2 and manganese in an amount by weight, expressed as elemental manganese, ranging from 10 ppm to 75 ppm, based on the weight of SiO2 contained in the precipitated silica.Similarly, the invention relates to a method for manufacturing at least one of (i) an elastomeric composition filled with precipitated silica, (ii) a tire part comprising (possibly composed of) an elastomeric composition filled with precipitated silica, and (iii) a tire comprising at least one part comprising (possibly composed of) an elastomeric composition loaded with precipitated silica, wherein said method comprises mixing at least one elastomer with precipitated silica, wherein said precipitated silica contains particulate SiO2 and manganese in an amount. Petition 870250080266, dated 08 / 09 / 2025, page 18 / 358 9 / 63 by weight, expressed as elemental manganese, ranging from 10 ppm to 75 ppm, based on the weight of SiO2 contained in the precipitated silica. Preferably, said precipitated silica additionally contains phosphorus in an amount by weight, expressed as elemental phosphorus, of at least 10 ppm, based on the weight of SiO2 contained in the precipitated silica. According to a preferred embodiment, said precipitated silica is obtainable or obtained according to the process of the present invention.

[0033] The invention further relates to an elastomeric composition filled with precipitated silica comprising at least one elastomer and said precipitated silica, to a tire part (possibly composed of) comprising said elastomeric composition filled with precipitated silica and to a tire comprising at least one part comprising (possibly composed of) said elastomeric composition filled with precipitated silica.

[0034] The invention also relates to a vehicle comprising said tire. The vehicle may be a motor vehicle, for example, a car, a van, a mobile home, a bus, a coach, a truck or a construction machine (such as a backhoe or a dump truck); alternatively, the vehicle may be a non-motor vehicle (such as a trailer or a cart).

[0035] The present invention solves the aforementioned problems of the prior art by providing a process for preparing precipitated silica from vegetable ash that is not only environmentally friendly but also economically advantageous. In fact, the process of the invention does not require any pretreatment of the plant, plant part and / or vegetable ash or any post-treatment of the precipitated silica, and, in particular, any washing step, to efficiently prepare a precipitated silica that has the desired properties. In fact, the precipitated silica obtainable or obtained from the invention can be advantageously employed for the manufacture of elastomeric compositions containing precipitated silica and tires with the Petition 870250080266, dated 08 / 09 / 2025, page 19 / 358 10 / 63 desired characteristics in terms of performance and mechanical and dynamic properties. DETAILED DESCRIPTION OF THE INVENTION Before the issues of the invention are described in detail, the following should be considered:

[0036] It should be understood that this invention is not limited to the particular embodiments described, since such embodiments may certainly vary. It is also to be understood that the terminology used herein is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

[0037] As used in this document, the singular forms “um”, “uma”, “o” and “a” include both singular and plural referents, unless the context clearly dictates otherwise. For example, “um composta” means one compound or more than one compound.

[0038] As used in this document, the terms “comprising”, “comprises” and “comprised of” are synonymous with “including”, “includes” or “containing”, “contains” and are inclusive or open-ended, and do not exclude additional members, elements or method steps not mentioned. As used in this document, it will be recognized that the terms “comprising”, “comprises” and “comprised of” encompass the terms “consisting of”, “consists of” and “consists of”.

[0039] Throughout this application, the term “about” is used to indicate that a value includes the standard deviation of error for the device or method that is employed to determine the value.

[0040] As used in this document, the term “average” refers to the numerical mean, unless otherwise indicated.

[0041] As used in this document, the terms “% by weight”, “% by p”, “percentage by weight” or “percentage of weight” are used interchangeably. The same applies to the terms “% by volume”, “% by Petition 870250080266, dated 08 / 09 / 2025, page 20 / 358 11 / 63 vol”, “percentage by volume” or “percentage of volume”, or “% by mol”, “% by m”, “percentage by mol” or “percent of mol”.

[0042] As used in this document, the terms “% by weight” or “% by weight” are used interchangeably to indicate “per thousand” (i.e., “per thousand”). The same applies to the terms “% by volume”, “% by vol”, or “% by mol” or “% by m”.

[0043] The recitation of numerical ranges by means of limits includes all whole numbers and, where appropriate, fractions encompassed within that range (for example, 1 to 5 may include 1, 2, 3 and 4 when referring, for example, to a number of elements, and may also include 1.5, 2, 2.75 and 3.80 when referring, for example, to measurements). The recitation of limits also includes the limit values ​​themselves (for example, 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited in this document is intended to include all subranges encompassed within it.

[0044] “X is substantially free of Y”, a patent term of the art, is used herein under its usual, commonly accepted meaning, allowing for a possible presence of Y in X provided that the amount, if any, of Y in X does not materially affect the basic characteristics of X. In the context of the present invention, the basic characteristics of a precipitated silica are the physical parameters determined in Table 4 and the end-use properties determined in Tables 6-8.

[0045] “X is essentially free of Y”, another technical term in patent law, is also used in this document under its usual meaning, allowing for a possible and unavoidable presence of traces, such as impurities, of Y in X, traces of which should be avoided as far as possible.

[0046] For the avoidance of doubt, “X is free from Y” is merely intended to mean that X is completely free from Y.

[0047] As used in this document, the term “manganese” encompasses manganese in any form contained in precipitated silica, notably manganese in at least one form Petition 870250080266, dated 09 / 08 / 2025, p. 21 / 358 12 / 63 selected from the group consisting of: manganese element, manganese on the surface of SiO2 particles, manganese embedded in SO2 particles, manganese silicate and manganese oxide in any oxidation state.

[0048] The amount by weight of manganese, for the purposes of this invention, is expressed as elemental manganese throughout the descriptive report.

[0049] As used in this document, the term phosphorus is intended to denote phosphorus in any form contained in precipitated silica, notably phosphorus in at least one form selected from the group consisting of: element phosphorus, phosphorus on the surface of SiO2 particles, phosphorus embedded in SiO2 particles, orthophosphate ion, polyphosphate ion and phosphides.

[0050] The amount by weight of phosphorus, for the purposes of the present invention, is expressed as elemental phosphorus throughout the descriptive report.

[0051] All references cited in this descriptive report are incorporated herein by reference in their entirety. In particular, the teachings of all references specifically mentioned herein are incorporated by reference.

[0052] Unless otherwise defined, all terms used in the disclosure of the invention, including technical and scientific terms, have the meaning normally understood by a person of ordinary skill in the art to which this invention pertains. For further guidance, definitions of terms are included for a better understanding of the teaching of the present invention.

[0053] In the following passages, different alternatives, embodiments and variants of the invention are defined in more detail. Each alternative and embodiment thus defined can be combined with any other alternative and embodiment, and this for each variant, unless otherwise indicated or if clearly incompatible when the range of values ​​of the same parameter. Petition 870250080266, dated 09 / 08 / 2025, p. 22 / 358 13 / 63 for dissociated. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

[0054] Furthermore, the features, structures, or particular characteristics described in this description may be combined in any suitable manner, as would be evident to a person skilled in the art of this disclosure, in one or more embodiments. Furthermore, although some embodiments described herein include some, but not other, features included in other embodiments, combinations of features from different embodiments are intended to be encompassed within the scope of the invention, and form different embodiments, as would be understood by a person skilled in the art.

[0055] The present invention relates to a process for producing precipitated silica from vegetable ash, the process comprising the following steps: (I) Reacting a vegetable ash containing SiO2 and manganese in a weight amount, expressed as elemental manganese, of at least 10 ppm, based on the weight of SiO2 contained in the vegetable ash, with an alkali metal base, preferably an alkali metal hydroxide, at a temperature of at least 100 °C in an aqueous reaction medium, so as to obtain an aqueous silicate solution comprising (i) SiO2 in the form of silicate anions and (ii) manganese in a weight amount, expressed as elemental manganese, of at least 10 ppm, based on the weight of SiO2 contained in the silicate solution, and (II) reacting the aqueous silicate solution with an acidifying agent at a temperature of at least 40 °C in an aqueous reaction medium having a pH exceeding 7.0 for at least part of the duration of the reaction, so as to achieve precipitation of SiO2 and produce a paste. Petition 870250080266, dated 09 / 08 / 2025, p. 23 / 358 14 / 63 aqueous fluid comprising particulate SiO2 and manganese in a weight amount, expressed as elemental manganese, of at least 10 ppm, based on the weight of SiO2 contained in the aqueous fluid paste.

[0056] According to a preferred embodiment, said vegetable ash contains manganese in an amount by weight, expressed as elemental manganese, of at least 15 ppm, at least 18 ppm, at least 20 ppm, at least 50 ppm, at least 100 ppm or at least 200 ppm, based on the weight of SiO2 contained in the vegetable ash. More preferably, said vegetable ash contains manganese in an amount by weight, expressed as elemental manganese, of at least 500 ppm, based on the weight of SiO2 contained in the vegetable ash. Even more preferably, said vegetable ash contains manganese in an amount by weight, expressed as elemental manganese, of at least 1000 ppm, based on the weight of SiO2 contained in the vegetable ash. Most preferably, said vegetable ash contains manganese in an amount by weight, expressed as elemental manganese, of at least 2000 ppm, based on the weight of SiO2 contained in the vegetable ash.

[0057] Advantageously, said vegetable ash contains manganese in an amount by weight, expressed as elemental manganese, of no more than 15,000 ppm, preferably no more than 12,000 ppm, more preferably no more than 9,000 ppm, even more preferably no more than 7,000 ppm, even more preferably no more than 5,000 ppm and most preferably no more than 3,500 ppm, based on the weight of SO2 contained in the vegetable ash. In some particular cases, said vegetable ash may contain manganese in a smaller amount by weight, for example, in an amount by weight, expressed as elemental manganese, of no more than 2,500 ppm, no more than 1,250 ppm or no more than 675 ppm, based on the weight of SiO2 contained in the vegetable ash.

[0058] In some embodiments, said vegetable ash contains manganese in an amount by weight, expressed as elemental manganese, Petition 870250080266, dated 09 / 08 / 2025, p. 24 / 358 15 / 63 in the range of 10 ppm to 5,000 ppm, based on the weight of SiO2 contained in the vegetable ash.

[0059] According to a preferred embodiment of the invention, said aqueous silicate solution contains manganese in an amount by weight, expressed as elemental manganese, of at most 500 ppm, preferably at most 375 ppm, more preferably at most 250 ppm, even more preferably at most 200 ppm, even more preferably at most 150 ppm and most preferably at most 100 ppm, based on the weight of SiO2 contained in the aqueous silicate solution.

[0060] In some particular cases, said aqueous silicate solution may contain manganese in a lower weight amount, for example, in a weight amount, expressed as elemental manganese, of at most 75 ppm, at most 50 ppm, at most 30 ppm, at most 25 ppm.

[0061] Furthermore, said aqueous silicate solution contains manganese in an amount by weight, expressed as elemental manganese, which is preferably at least 10 ppm, more preferably at least 30 ppm and even more preferably at least 50 ppm, based on the total weight of SiO2 contained in the aqueous silicate solution.

[0062] In some particular cases, said aqueous silicate solution may contain manganese in an amount by weight, expressed as elemental manganese, ranging from 10 ppm to 100 ppm, from 10 ppm to 80 ppm, from 10 ppm to 75 ppm, from 15 ppm to 50 ppm or from 18 ppm to 25 ppm, based on the weight of SiO2 contained in the aqueous silicate solution.

[0063] According to one embodiment of the invention, the aqueous fluid paste obtained in step (II) contains manganese in the same amounts as those disclosed for the aqueous silicate solution.

[0064] According to one embodiment of the invention, during step (I), vegetable ash is reacted with an alkali metal base at a temperature of at least 120 °C, preferably at least 140 °C and Petition 870250080266, dated 09 / 08 / 2025, p. 25 / 358 16 / 63 more preferably at least 160 °C. In addition, step (I) is carried out at a temperature advantageously of no more than 250 °C, preferably no more than 220 °C and more preferably no more than 200 °C. Good results were obtained when vegetable ash was reacted with the alkali metal base at a temperature ranging from 140 °C to 220 °C, preferably from 160 °C to 200 °C.

[0065] Preferably, said alkali metal base is selected from the group consisting of: tetra-alkylammonium hydroxide (NR4+, OH) where R is an alkyl chain, preferably a C1-C4 alkyl chain, a sodium or potassium-containing base, or a combination thereof. More preferably, said alkali metal base is an alkali metal hydroxide selected from sodium or potassium hydroxide.

[0066] According to a particularly preferred embodiment, the process according to the present invention comprises a step (A), prior to step (I) of burning a plant and / or a part of a plant in order to obtain vegetable ash, wherein said plant and / or part of a plant contains SiO2 and manganese in an amount by weight, expressed as elemental manganese, which is the same as disclosed above for vegetable ash, based on the weight of SiO2 contained in the plant and / or part of a plant. In other words, said vegetable ash is obtained from the combustion of a plant and / or a part of a plant.

[0067] Preferably, said plant and / or plant part contains manganese in a weight quantity, expressed as elemental manganese, of at least 15 ppm, at least 18 ppm, at least 20 ppm, at least 50 ppm, at least 100 ppm or at least 200 ppm, based on the weight of SiO2 contained in the plant and / or plant part. More preferably, said plant and / or plant part contains manganese in a weight quantity, expressed as elemental manganese, of at least 500 ppm, based on the weight of SiO2 contained in the plant and / or plant part. Even more preferably, said plant and / or plant part contains manganese in a weight quantity, Petition 870250080266, dated 08 / 09 / 2025, page 26 / 358 17 / 63 expressed as elemental manganese, of at least 1000 ppm, based on the weight of SiO2 contained in the plant and / or plant part. More preferably, said plant and / or plant part contains manganese in an amount by weight, expressed as elemental manganese, of at least 2000 ppm, based on the weight of SiO2 contained in the plant and / or plant part.

[0068] Advantageously, said plant and / or plant part contains manganese in a weight quantity, expressed as elemental manganese, of no more than 15,000 ppm, preferably no more than 12,000 ppm, more preferably no more than 9,000 ppm, even more preferably no more than 7,000 ppm, even more preferably no more than 5,000 ppm and most preferably no more than 3,500 ppm, based on the weight of SO2 contained in the plant and / or plant part. In some particular cases, said plant and / or plant part may contain manganese in a smaller weight quantity, for example, in a weight quantity, expressed as elemental manganese, of no more than 2,500 ppm, no more than 1,250 ppm or no more than 675 ppm, based on the weight of SiO2 contained in the plant and / or plant part.

[0069] According to a particularly preferred embodiment of the invention, said plant and / or plant part contains manganese in an amount by weight, expressed as elemental manganese, ranging from 10 ppm to 5000 ppm, preferably from 15 ppm to 2500 ppm, more preferably from 18 ppm to 1250 ppm, even more preferably from 18 ppm to 675 ppm, based on the weight of SiO2 contained in the plant and / or plant part.

[0070] According to one embodiment of the present invention, the plant and / or plant part, plant ash, aqueous silicate solution and / or aqueous fluid paste additionally contain phosphorus. The plant and / or plant part may contain phosphorus in an amount by weight, expressed as elemental phosphorus, of at least 10 ppm, at least 15 ppm or at least 20 ppm, based on the weight of SiO2 contained in the plant and / or plant part. Petition 870250080266, dated 09 / 08 / 2025, p. 27 / 358 18 / 63

[0071] Advantageously, the plant and / or plant part additionally contains phosphorus in a higher amount by weight, for example, in an amount by weight expressed as elemental phosphorus, of at least 500 ppm, preferably at least 1000 ppm, more preferably at least 1500 ppm, even more preferably at least 1650 ppm, at least 1700 ppm or at least 1750 ppm, based on the weight of SiO2 contained in the plant and / or plant part.

[0072] Preferably, the plant and / or plant part contains phosphorus in an amount by weight, expressed as elemental phosphorus, of no more than 5000 ppm, more preferably no more than 3500 ppm, even more preferably no more than 2500 ppm, and most preferably no more than 2000 ppm, based on the weight of SiO2 contained in the plant and / or plant part.

[0073] In some particular cases, the plant and / or plant part contains phosphorus in a weight quantity, expressed as elemental phosphorus, which is at most 1250 ppm or at most 675 ppm, based on the weight of SiO2 contained in the plant and / or plant part.

[0074] According to one embodiment of the invention, the plant and / or plant part contains phosphorus in an amount by weight, expressed as elemental phosphorus, ranging from 10 ppm to 5000 ppm, or from 15 ppm to 2500 ppm, or from 20 ppm to 1250 ppm, based on the weight of SiO2 contained in the plant and / or plant part.

[0075] Similarly, vegetable ash, aqueous silicate solution and / or aqueous fluid paste may additionally contain phosphorus in an amount by weight, expressed as elemental phosphorus, of at least 10 ppm, at least 15 ppm or at least 20 ppm, based on the weight of SiO2 contained, respectively, in the vegetable ash, aqueous silicate solution and / or aqueous fluid paste.

[0076] Advantageously, vegetable ash, aqueous silicate solution and / or aqueous fluid paste additionally contain phosphorus in a Petition 870250080266, dated 09 / 08 / 2025, p. 28 / 358 19 / 63 higher quantity by weight, for example, in a weight quantity expressed as elemental phosphorus, of at least 500 ppm, preferably at least 1000 ppm, more preferably at least 1500 ppm, even more preferably at least 1650 ppm, at least 1700 ppm or at least 1750 ppm, based on the weight of SiO2 contained, respectively, in the vegetable ash, the aqueous silicate solution and / or the aqueous fluid paste. In addition, the aqueous silicate solution and / or the aqueous fluid paste further contain phosphorus in a weight quantity, expressed as elemental phosphorus, which is even more preferably at least 2000 ppm and most preferably at least 2500 ppm, based on the weight of SiO2 contained, respectively, in the aqueous silicate solution and / or the aqueous fluid paste.

[0077] Preferably, the vegetable ash, aqueous silicate solution and / or aqueous fluid paste contain phosphorus in an amount by weight, expressed as elemental phosphorus, of no more than 5000 ppm, more preferably no more than 3500 ppm or even more preferably no more than 3000 ppm, based on the weight of SiO2 contained, respectively, in the vegetable ash, aqueous silicate solution and / or aqueous fluid paste. In addition, the vegetable ash contains phosphorus in an amount by weight, expressed as elemental phosphorus, which is even more preferably no more than 2500 ppm and most preferably no more than 2000 ppm, based on the weight of SiO2 contained in the vegetable ash.

[0078] In some particular cases, vegetable ash, aqueous silicate solution and / or aqueous fluid paste additionally contain phosphorus in an amount by weight, expressed as elemental phosphorus, of no more than 1250 ppm, or at least 675 ppm, based on the weight of SiO2 contained, respectively, in the vegetable ash, aqueous silicate solution and / or aqueous fluid paste.

[0079] According to one embodiment of the invention, vegetable ash, aqueous silicate solution and / or aqueous fluid paste contain phosphorus. Petition 870250080266, dated 09 / 08 / 2025, p. 29 / 358 20 / 63 in a weight quantity, expressed as elemental phosphorus, ranging from 10 ppm to 5000 ppm, or from 15 ppm to 2500 ppm, or from 20 ppm to 1250 ppm, based on the weight of SiO2 contained, respectively, in vegetable ash, aqueous silicate solution and / or aqueous fluid paste.

[0080] According to one embodiment of the invention, the aqueous fluid paste obtained in step (II) preferably contains phosphorus in the same amounts as those disclosed for the aqueous silicate solution.

[0081] Without adhering to a specific theory of mechanism, it was found that the amount by weight of manganese and, when present, of phosphorus contained in the plant and / or plant part, and, in turn, contained in the plant ash, as described above, has no negative impact on the preparation of the aqueous silicate solution and on the preparation of precipitated silica, and on their properties.

[0082] Similarly, it was also found that the presence of manganese and, when present, phosphorus, contained in the aqueous silicate solution also does not have an impact on the preparation of precipitated silica and its properties.

[0083] Additionally, it was found that, for the purposes of the present invention, it is not necessary to treat the plant and / or part of the plant or the plant ash to remove the manganese and, when present, the phosphorus contained therein, as the presence of manganese and, when present, phosphorus, in the weight amounts described above does not have a negative impact on the properties of the precipitated silica.

[0084] Consequently, according to one embodiment, the invention process may comprise step (A) and be free of any step (B) after step (A) and before step (I) which comprises reburning the vegetable ash.

[0085] According to one embodiment, the invention process may comprise step (A) and may be free of any step (B) thereafter. Petition 870250080266, dated 08 / 09 / 2025, page 30 / 358 21 / 63 stage (A) and before stage (I) which involves washing the vegetable ash with a liquid containing water or acidified water.

[0086] According to one embodiment, the invention process may comprise step (A) and be free of any step (B) after step (A) and before step (I) comprising performing acid leaching and / or acid wetting of vegetable ash.

[0087] Preferably, said acid leaching and / or acid wetting is carried out with an acidifying agent; more preferably, with HCl; even more preferably, with a 1 N or 6 N HCl solution.

[0088] According to one embodiment, said acid leaching can be carried out by treating vegetable ash under reflux with said acidifying agent; preferably with HCl; even more preferably with 1 N or 6 N HCl, for at least 1 hour; preferably for at least 1.5 hours.

[0089] Said acid wetting is preferably carried out by immersing the vegetable ash in said acidifying agent; preferably HCl; more preferably, 1 N or 6 N HCl solution, for at least 1 hour; preferably for at least 3 hours; more preferably, from 3 to 7 hours.

[0090] According to one embodiment, the process of the invention may comprise step (A) and be free of any step (B) after step (A) and before step (I) comprising at least one of (i) washing the vegetable ash with a liquid containing water or acidified water and (ii) acid leaching and / or acid wetting of the vegetable ash.

[0091] Washing the plant with a liquid containing water or acidified water, acid leaching of plant ash and acid wetting of plant ash are operations that would otherwise generally result in a partial or complete removal of manganese and / or, when present, phosphorus from the plant ash. Petition 870250080266, dated 08 / 09 / 2025, page 31 / 358 22 / 63

[0092] According to a particularly preferred embodiment, the process of the invention comprises step (A) and is free of any step (B) after step (A) and before step (I) of removing part or all of the manganese and / or, when present, phosphorus from the vegetable ash.

[0093] According to the invention, said step (B) according to any of the embodiments above can be considered as a pre-treatment step of vegetable ash.

[0094] According to another particularly preferred embodiment, the process of the invention may comprise step (A) and be free of any step (B') prior to step (A) which comprises washing the plant and / or plant part with a liquid containing water or acidified water.

[0095] According to one embodiment, the process of the invention may comprise step (A) and be free of any step (B') prior to step (A) which comprises acid leaching and / or acid wetting of the plant and / or part of the plant.

[0096] Preferably, said acid leaching and / or acid wetting is as defined above for step (B).

[0097] According to one embodiment, the process of the invention may comprise step (A) and be free of any step (B') prior to step (A) comprising at least one of (i) washing the plant and / or plant part with a liquid containing water or acidified water and (ii) acid leaching and / or acid wetting of the plant and / or plant part.

[0098] Washing the plant and / or part of a plant with a liquid containing water or acidified water, acid leaching of the plant and / or part of a plant, and acid wetting of the plant and / or part of a plant would otherwise and generally result in a partial or total removal of manganese and / or, when present, phosphorus from the plant and / or part of a plant.

[0099] According to a particularly preferred embodiment, the process of the invention comprises step (A) and is free from any step (B') of removing part or all of the manganese and / or, when Petition 870250080266, dated 09 / 08 / 2025, p. 32 / 358 23 / 63 present, phosphorus, of the plant and / or part of the plant. According to the invention, said step (B') can be considered as a pre-treatment step of the plant and / or part of the plant.

[0100] According to the invention, vegetable ash that has not been subjected to any step (B), according to any of the embodiments as described above, is considered to be untreated vegetable ash, preferably, vegetable ash that has not been washed and / or reburned.

[0101] Similarly, according to the invention, the plant and / or part of a plant that has not been subjected to any step (B'), according to any of the embodiments described above, is considered an untreated plant and / or part of a plant, preferably an unwashed plant and / or part of a plant.

[0102] Without adhering to a specific theory, it has been found that the process according to the present invention does not require any pretreatment of the plant, plant part and / or vegetable ash to remove the manganese and, when present, phosphorus contained therein. On the contrary, it has been surprisingly found that the presence of said manganese and / or, when present, phosphorus in the plant, plant part and / or vegetable ash does not affect the synthesis of precipitated silica and that, in turn, the precipitated silica thus obtained still possesses the desirable mechanical and rheological properties, which are particularly advantageous for tire applications.

[0103] According to the invention, the plant is preferably an angiosperm, more preferably a monocotyledon or eudicotyledon, with maximum preference a plant belonging to the selected family of the group consisting of Poaceae, Equisetaceae, Cyperaceae, Cucurbitaceae, Cannabaceae, Arecaceae, Brassicaceae and combinations thereof. Petition 870250080266, dated 09 / 08 / 2025, p. 33 / 358 24 / 63

[0104] According to one embodiment of the invention, the plant is a tree. Preferably, the tree is selected from the group consisting of: pine, oak, birch, elm and combinations thereof.

[0105] Preferably, the plant belonging to the Poaceae family is selected from the group consisting of: rice, wheat, sugar cane, bamboo, oats, barley, rye, sorghum, triticale, canary grass, cane, maize, miscanthus and combinations thereof.

[0106] Preferably, the plant belonging to the Equisetaceae family is field horsetail.

[0107] Preferably, the plant belonging to the family of Cyperaceae is a type of nutgrass.

[0108] Preferably, the plant belonging to the family of Cucurbitaceae is selected from the group that consists of: melon, watermelon, pumpkin, cucumber, and combinations thereof.

[0109] Preferably, the plant belonging to the Cannabaceae family is hemp.

[0110] Preferably, the plant belonging to the family of Arecaceae is palm tree.

[0111] Preferably, the plant belonging to the family of Brassicaceae is rapeseed.

[0112] It is preferable that the plant containing silica (plant containing SiO2) be a plant selected from the group consisting of rice, wheat, rapeseed, barley, bamboo, field horsetail, sedge, watermelon and combinations thereof.

[0113] Preferably, the said plant part is selected from the group consisting of: a root, a trunk, a leaf, a flower, a fruit, a bark, a stem, a stalk, a wood and combinations thereof.

[0114] According to the invention, the plant part can also be derived from a plant processing, such as straw (for example, straw from Petition 870250080266, dated 09 / 08 / 2025, p. 34 / 358 25 / 63 cereals), bagasse (e.g., sugarcane bagasse), oil (e.g., palm oil), sawdust (e.g., tree sawdust) and / or pellets.

[0115] It is preferable that said plant part be selected from the group consisting of: rice husk, rice straw, wheat husk, wheat straw, barley straw, barley husk, sugarcane bagasse, sugarcane leaves, bamboo trunk, bamboo leaves, corncob, palm oil, miscanthus stalk, miscanthus leaves, sedge leaf, watermelon fruit, tree wood and combinations thereof.

[0116] In a particularly preferred embodiment of the invention, the plant is rice and, preferably, the plant part is a husk.

[0117] According to the invention, the combustion of the plant and / or part of a plant (step A) described above is carried out by conventional techniques by burning a part of a plant and / or a plant that contains silica.

[0118] In one embodiment, the combustion of the plant and / or part of the plant is carried out at a temperature of 300 °C to 1500 °C; preferably, 500 °C to 1000 °C. According to another embodiment, the combustion of the plant and / or part of the plant is carried out at a temperature above 700 °C; Preferably, at a temperature of more than 700 °C to 1000 °C. According to another embodiment, the combustion of the plant and / or part of the plant is carried out at a temperature of no more than 700 °C; preferably, at a temperature of 500 °C to 700 °C.

[0119] According to the invention, the acidifying agent of step (II) described above is selected from the group consisting of: a mineral acid, preferably selected from the group consisting of: sulfuric acid (H2SO4), hydrochloric acid (HCl), nitric acid (HNO3), phosphoric acid (H3PO4) and combinations thereof, and an organic acid, preferably selected from the group consisting of: acetic acid, formic acid, carbonic acid and combinations thereof.

[0120] According to the invention, step (II) of the process described above is carried out in an aqueous reaction medium that has a pH that exceeds Petition 870250080266, dated 08 / 09 / 2025, page 35 / 358 26 / 63 7.0 for at least part of the reaction duration; preferably for at least 25% of the reaction duration; more preferably for at least 28% of the reaction duration; and even more preferably for at least 33% of the reaction duration. In some embodiments, step (II) of the process described above is carried out in an aqueous reaction medium that has a pH that exceeds 7.0 for at most 66% of the reaction duration; preferably for at most 50% of the reaction duration; in some other embodiments, step (II) of the process described above is carried out in an aqueous reaction medium that has a pH that exceeds 7.0 for more than 50% of the reaction duration; preferably for at least 90% of the reaction duration; more preferably for at least 95% of the reaction duration; and even more preferably for the entire reaction duration.

[0121] Preferably, step (II) of the reaction of the aqueous silicate solution with the acidifying agent is carried out at a temperature of at least 50 °C; more preferably, at least 60 °C; even more preferably, at least 75 °C; and, most preferably, at least 80 °C. Furthermore, step (II) is advantageously carried out at a temperature of at most 150 °C; preferably, less than 100 °C; and, most preferably, at most 95 °C. Satisfactory results were obtained when step (II) was carried out at a temperature in the range of 60 °C to less than 100 °C. Excellent results were obtained when step (II) was carried out at a temperature in the range of 75 °C to 95 °C.

[0122] Preferably, the aqueous reaction medium of step (I) and / or (II) of the process of the invention is water.

[0123] According to the invention, the process may further comprise the steps of: (III) filter the aqueous fluid paste obtained after step (II), preferably using a filter press, in order to obtain a filter cake comprising particulate SiO2; (IV) optionally, wash the filter cake with a liquid containing water; Petition 870250080266, dated 08 / 09 / 2025, page 36 / 358 27 / 63 (V) liquefy the filter cake into a fluidizable aqueous suspension comprising particulate SiO2 by adding a liquid containing water to the filter cake; (VI) dry the fluidizable aqueous suspension, preferably by means of a spray dryer, in order to obtain precipitated silica.

[0124] According to one embodiment of the invention, step (V) further comprises subjecting the filter cake to a mechanical and / or chemical treatment (in addition to adding a liquid containing water to the filter cake).

[0125] According to one embodiment, the process of the present invention is free of any step (B”) after step (VI) which comprises washing the precipitated silica with a liquid containing water or acidified water.

[0126] According to one embodiment, the process of the invention is free of any step (B”) after step (VI) which comprises performing acid leaching and / or acid wetting of the precipitated silica.

[0127] Preferably, said acid leaching and / or acid wetting is as defined above for steps (B) and (B').

[0128] According to one embodiment, the process of the invention is free of any step (B”) after step (VI) comprising at least one action among (i) washing the precipitated silica with a liquid containing water or acidified water and (ii) acid leaching and / or acid wetting of the precipitated silica.

[0129] Washing precipitated silica with a liquid containing water or acidified water, leaching acid from precipitated silica and wetting acid precipitated silica would otherwise generally result in a partial or complete removal of manganese and / or, when present, some or all of the phosphorus from the precipitated silica.

[0130] According to a particularly preferred modality, to the process according to Petition 870250080266, dated 08 / 09 / 2025, page 37 / 358 28 / 63 the present invention is free from any step (B''), after step (VI), of removing part or all of the manganese and / or, when present, part or all of the phosphorus from the precipitated silica.

[0131] According to the invention, said step (B'') can be considered as a post-treatment step of the precipitated silica.

[0132] According to one embodiment, the process according to the present invention does not involve (i.e., is free from) a xerogel formation step.

[0133] According to the invention, the precipitated silica obtained at the end of the above process may also contain other elements (derived from synthesis and, in particular, from the use of untreated vegetable ash and untreated plant and / or plant parts) selected from the group consisting of: Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Ni, Pb, S, Sb, Ti, Zn, K, Na and combinations thereof.

[0134] The present invention also relates to a precipitated silica containing particulate SiO2 and manganese in an amount by weight, expressed as elemental manganese, ranging from 10 ppm to 75 ppm, based on the weight of SiO2 contained in the precipitated silica. The present invention also relates to the use of said precipitated silica for the manufacture of an elastomeric composition filled with precipitated silica.

[0135] Preferably, said precipitated silica contains manganese in an amount by weight, expressed as elemental manganese, of at least 10 ppm, preferably at least 15 ppm and more preferably at least 18 ppm, based on the total weight of SiO2 contained in the precipitated silica.

[0136] Preferably, said precipitated silica contains manganese in an amount by weight, expressed as elemental manganese, of no more than 75 ppm, preferably no more than 50 ppm, more preferably no more than 30 ppm and even more preferably at least 25 ppm, based on the total weight of SiO2 contained in the precipitated silica. Petition 870250080266, dated 09 / 08 / 2025, p. 38 / 358 29 / 63

[0137] According to a particularly preferred embodiment of the invention, said precipitated silica contains manganese in an amount by weight, expressed as elemental manganese, ranging from 15 ppm to 50 ppm, preferably from 18 ppm to 30 ppm, more preferably from 18 ppm to 25 ppm, based on the weight of SiO2 contained in the precipitated silica.

[0138] Preferably, said precipitated silica additionally contains phosphorus in an amount by weight, expressed as elemental phosphorus, of at least 10 ppm, preferably at least 15 ppm, more preferably at least 20 ppm and even more preferably at least 23 ppm based on the weight of SiO2 contained in the precipitated silica.

[0139] Preferably, said precipitated silica contains phosphorus in an amount by weight, expressed as elemental phosphorus, of no more than 300 ppm, more preferably no more than 100 ppm, even more preferably no more than 50 ppm, even more preferably no more than 30 ppm, based on the weight of SiO2 contained in the precipitated silica.

[0140] According to one embodiment of the invention, said precipitated silica contains phosphorus in an amount by weight, expressed as elemental phosphorus, ranging from 10 ppm to 300 ppm, preferably from 15 ppm to 100 ppm, more preferably from 20 ppm to 50 ppm, even more preferably from 23 ppm to 30 ppm, based on the weight of SiO2 contained in the precipitated silica.

[0141] Preferably, said precipitated silica contains SiO2 in particulate form in an amount by weight of at least 90.0 % by weight, more preferably at least 93.0 % by weight and even more preferably at least 95.0 % by weight, based on the total weight of the precipitated silica.

[0142] Preferably, said precipitated silica contains SiO2 in particulate form in an amount by weight of at most 99.0% by weight, preferably at most 98.0%, more preferably at least 97.0% by weight, based on the weight of the precipitated silica. Petition 870250080266, dated 08 / 09 / 2025, page 39 / 358 30 / 63

[0143] According to one embodiment of the invention, said precipitated silica contains SiO2 in particulate form in an amount by weight ranging from 90.0% to 99.0% by weight, preferably from 93.0% to 98.0%, more preferably from 95.0% to 97.0% by weight, based on the weight of the precipitated silica.

[0144] Preferably, the precipitated silica is substantially free of SiO2 particles to which an organic chemical moiety is covalently linked via a Si-C bond; it may be essentially free or even free of SiO2 particles to which an organic chemical moiety is covalently linked via a Si-C bond.

[0145] Preferably, said precipitated silica is substantially free, essentially free, or even free of SiO2 particles to which an organic chemical moiety is covalently bonded (it does not matter what the covalent bond is between the SiO2 particles and the organic chemical moiety).

[0146] More preferably, said precipitated silica differs from any organically modified precipitated silica.

[0147] As used in this document, the term “organically modified precipitated silica” denotes precipitated silica comprising SiO2 particles and a substantial amount of (i) an organic compound and / or (ii) an organic chemical moiety that is covalently bonded to the SiO2 particles. Organically modified precipitated silica may be precipitated silica comprising a substantial amount of an organic compound (e.g., polyethylene glycol) that is not covalently bonded to the SiO2 particles. Organically modified precipitated silica may be precipitated silica comprising a substantial amount of an organic chemical moiety that is covalently bonded to the SiO2 particles; such organically modified precipitated silica typically results from a chemical reaction between an organic compound (e.g., methylsiliconate). Petition 870250080266, dated 08 / 09 / 2025, page 40 / 358 31 / 63 of potassium) and SiO2 particles. An organically modified precipitated silica thus contains a substantial amount of carbon, notably in the form of the organic compound and / or the organic chemical moiety. An organically modified precipitated silica may contain at least 0.5%, at least 0.75%, or even at least 1% carbon, based on the weight of SiO2 contained in the modified precipitated silica.

[0148] Said carbon is a carbon contained in the organic chemical portions mentioned above covalently bonded to SiO2 particles through a Si-C bond.

[0149] In contrast, said precipitated silica is advantageously and substantially free, essentially free, or even free of carbon. Its carbon content, as determined by the C / S method, is advantageously in the range of 0 to less than 0.5%; preferably, from 0 to 4000 ppm; more preferably, from 0 to 3000 ppm; even more preferably, from 0 to 2000 ppm; and even more preferably, from 0 to 1000 ppm, based on the weight of SiO2 contained in the precipitated silica.

[0150] According to one embodiment, said precipitated silica has a specific BET surface area of ​​at least 165 m2 / g, preferably at least 180 m2 / g, more preferably at least 200 m2 / g. According to a preferred embodiment, said precipitated silica has a specific BET surface area of ​​at most 290 m2 / g; preferably at most 280 m2 / g; even more preferably in the range of 165 m2 / g to 280 m2 / g.

[0151] According to another embodiment, said precipitated silica has a specific surface area of ​​CTAB of at least 155 m2 / g; preferably, of at least 165 m2 / g; more preferably, of at least 180 m2 / g. According to a preferred embodiment, the precipitated silica has a specific surface area of ​​CTAB of at most 225 m2 / g; preferably, of at most 220 m2 / g; even more preferably, in the range of 155 m2 / g to 220 m2 / g. Petition 870250080266, dated 09 / 08 / 2025, p. 41 / 358 32 / 63

[0152] According to one embodiment, said precipitated silica has a d50 in the range of 20 nm to 200 nm, preferably from 50 nm to 180 nm. According to the invention, said d50 is measured by centrifugal sedimentation, preferably by centrifugal sedimentation in a disc centrifuge using a centrifugal photosedimentometer (CPS).

[0153] According to a particularly preferred embodiment, said precipitated silica is obtainable or obtained by the process according to the present invention, as described above.

[0154] Without adhering to a specific theory, it has been found that, in vegetable ash, manganese is considered to be notably present in one or more forms that are insoluble in a basic medium, i.e., that cannot be dissolved by an alkali metal base containing sodium, such as NaOH. These may include one or more manganese oxides or mixed oxides of manganese with other metals, such as aluminum and / or iron. Thus, it can be concluded that this may result in lower values ​​for the manganese content in the aqueous silicate solution than in vegetable ash.

[0155] Furthermore, in the aqueous fluid paste obtained after step (II), a greater amount of manganese is considered to be present in the aqueous liquid phase of the fluid paste in the form of manganese ions (Mn2+ and / or Mn3+). According to one embodiment of the present invention, when the aqueous fluid paste is filtered according to step (III) to obtain a filter cake, a significant amount of such manganese ions thus accompanies the liquid phase of the fluid paste and is thus separated from the filter cake from which the precipitated silica is obtained. A fortiori, if the filter cake is washed according to one embodiment of the present invention, a certain residual amount of manganese possibly present in the filter cake, for example, as manganese salts, can be eliminated by washing.Therefore, without adhering to a specific theory, it can be concluded that this may result in lower manganese content in precipitated silica than in aqueous silicate solution and vegetable ash. Petition 870250080266, dated 09 / 08 / 2025, p. 42 / 358 33 / 63

[0156] Unlike manganese, phosphorus is considered to be present in plant ash in one or more forms that are highly soluble in a basic aqueous medium (such as hydrogen phosphate) and that can be and are easily extracted by an alkali metal base containing sodium, such as NaOH.

[0157] Without adhering to a specific theory, it can be concluded that the possibly higher phosphorus content in the aqueous silicate solution than in the vegetable ash according to one embodiment of the present invention does not involve any creation of phosphorus, but merely reflects the fact that phosphorus is extracted from the vegetable ash with a better yield than Si. A particularly high phosphorus content in the silicate can be achieved when an excessive amount of vegetable ash (expressed as SO2 content) is used compared to the amount of sodium-containing alkali metal base, such as NaOH.

[0158] The present invention also relates to a method for preparing an elastomeric composition filled with precipitated silica, said method comprising mixing at least one elastomer with the precipitated silica, as described above.

[0159] The present invention also relates to an elastomeric composition filled with precipitated silica comprising at least one elastomer and the precipitated silica, as described above.

[0160] According to the present invention, precipitated silica is employed within said elastomeric composition filled with precipitated silica as a reinforcing filler.

[0161] Preferably, said at least one elastomer has at least a glass transition temperature of -150 to +300 °C, for example, -150 to +20 °C.

[0162] Notable non-limiting examples of suitable elastomers are composed of Petition 870250080266, dated 08 / 09 / 2025, page 43 / 358 34 / 63 diene elastomers. For example, elastomers derived from aliphatic or aromatic monomers comprising at least one unsaturation may be used, such as, in particular, ethylene, propylene, butadiene, isoprene, styrene, acrylonitrile, isobutylene or vinyl acetate, polybutyl acrylate or mixtures thereof. In addition, mention may be made of functionalized elastomers, i.e., elastomers functionalized by chemical groups positioned along the macromolecular chain and / or at one or more of its ends (for example, by functional groups capable of reacting with the surface of SiO2 particles) and halogenated polymers. Reference may also be made to polyamides, ethylene homo- and copolymer, propylene homo- and copolymer.

[0163] Among diene elastomers, mention may be made, for example, of polybutadienes (BRs), polyisoprenes (IRs), butadiene copolymers, isoprene copolymers, or mixtures thereof, and, in particular, styrene / butadiene copolymers (SBRs, in particular ESBRs (emulsion) or SSBRs (solution)), isoprene / butadiene copolymers (BIRs), isoprene / styrene copolymers (SIRS), isoprene / butadiene / styrene copolymers (SBIRs), ethylene / propylene / diene terpolymers (EPDMs), and also associated functionalized polymers (exhibiting, for example, pendant polar groups or polar groups at the chain end, which can interact with SiO2 particles).

[0164] In addition, mention may be made of natural rubber (NR) and epoxidized natural rubber (ENR).

[0165] Elastomeric compositions filled with precipitated silica can be vulcanized with sulfur (vulcanized elements are, Petition 870250080266, dated 08 / 09 / 2025, page 44 / 358 35 / 63 then, obtained) or crosslinked, in particular, with peroxides or other crosslinking systems (e.g., diamines or phenolic resins).

[0166] The elastomeric composition filled with precipitated silica according to one embodiment of the present invention may also comprise at least one coupling agent and / or at least one coating agent, and / or, finally, an antioxidant.

[0167] In particular, use may be made, as coupling agents, of “symmetric” or “asymmetric” silane polysulfides; more particularly, mention may be made of bis((C1-C4)alkoxyl(C1-C4)alkylsilyl(C1C4)alkyl)polysulfides (in particular, disulfides, trisulfides or tetrasulfides), such as, for example, bis(3-(trimethoxysilyl)propyl)polysulfides or bis(3(triethoxysilyl)propyl)polysulfides, such as triethoxysilylpropyl tetrasulfide.

[0168] In addition, mention may be made of monoethoxydimethylsilylpropyl tetrasulfide.

[0169] In addition, mention may be made of silanes comprising thiol-free or masked functional groups.

[0170] The coupling agent can be previously grafted onto the elastomer. It can also be used in the free state or grafted onto the surface of the SiO2 particles.

[0171] The coupling agent may optionally be combined with an appropriate coupling activator, i.e., a compound which, when mixed with that coupling agent, increases the effectiveness of the latter.

[0172] The amount of precipitated silica that can be employed in said precipitated silica-filled elastomeric composition can vary over a relatively wide range. Typically, it represents from 10% to 200% by weight; in particular, from 20% to 150% by weight; especially, from 20% to 80% by weight, for example, from 30% to 70% by weight, of the amount of at least one elastomer. Alternatively, the weight proportion of silica Petition 870250080266, dated 08 / 09 / 2025, page 45 / 358 36 / 63 precipitated from the invention in the elastomeric composition filled with precipitated silica can be from 80% to 120% by weight, for example, from 90% to 110% by weight, of the amount of at least one elastomer.

[0173] As described above, precipitated silica can advantageously constitute the entire inorganic reinforcing filler and even the entire reinforcing filler of the elastomeric composition.

[0174] As described above, precipitated silica can optionally be combined with at least one other reinforcing filler, such as, in particular, a highly dispersible commercial silica, such as, for example, Zeosil® 1165, Zeosil® 1115 MP or Zeosil® 1085 MP precipitated silica (commercially available from Solvay); another inorganic reinforcing filler, such as, for example, alumina, in fact, even an organic reinforcing filler, in particular, carbon black (optionally, covered with an inorganic layer, for example, of SiO2).

[0175] Precipitated silica then preferably constitutes at least 50% by weight; in fact, even 80% by weight, of the total amount of reinforcing filler.

[0176] This elastomeric composition filled with precipitated silica can be used for the manufacture of a tire part. So another objective of the present invention is the use of the elastomeric composition filled with precipitated silica, as described above, for the manufacture of a tire part comprising (possibly composed of) said elastomeric composition filled with precipitated silica.

[0177] The present invention also relates to a method for manufacturing a tire part comprising (possibly composed of) said elastomeric composition filled with precipitated silica, wherein said method comprises (i) mixing at least one elastomer with precipitated silica, as described above, in order to obtain the precipitated silica-filled elastomeric composition described above and (ii) molding the Petition 870250080266, dated 08 / 09 / 2025, page 46 / 358 37 / 63 elastomeric composition filled with precipitated silica thus obtained in the tire part.

[0178] Another objective of the present invention is said tire part comprising (possibly composed of) the elastomeric composition filled with precipitated silica as described above. Preferably, said tire part is a tire tread.

[0179] The present invention also relates to the use of the precipitated silica-filled elastomeric composition described above for the manufacture of a tire comprising at least one part comprising (possibly composed of) a precipitated silica-filled elastomeric composition as described above (i.e., the tire part according to the present invention).

[0180] The invention also relates to a method for manufacturing a tire comprising at least one part comprising (possibly composed of) the precipitated silica-filled elastomeric composition as described above (i.e., the tire part according to the present invention), wherein said method comprises (i) mixing at least one elastomer with the precipitated silica as described above so as to obtain the precipitated silica-filled elastomeric composition as described above, (ii) molding the precipitated silica-filled elastomeric composition thus obtained into a tire part comprising (possibly composed of) the precipitated silica-filled elastomeric composition, and (iii) assembling the tire part thus molded comprising (possibly composed of) the precipitated silica-filled elastomeric composition with at least one tire part other than the tire part comprising (possibly,composed of) an elastomeric composition filled with precipitated silica in order to obtain the tire.

[0181] The present invention also relates to a tire comprising the tire part comprising (possibly composed of) the Petition 870250080266, dated 09 / 08 / 2025, p. 47 / 358 38 / 63 elastomeric composition filled with precipitated silica as described above and a vehicle comprising said tire.

[0182] The present invention further relates to precipitated silica obtainable or obtained by the process described above and its use / method for manufacturing (i) an elastomeric composition filled with precipitated silica, (ii) a tire part comprising (possibly composed of) an elastomeric composition filled with precipitated silica and / or (iii) a tire comprising at least one part comprising (possibly composed of) an elastomeric composition loaded with precipitated silica, and said elastomeric composition filled with precipitated silica, tire part, tire and / or vehicle as described in any of the embodiments described above.

[0183] If the disclosure of any patents, patent applications and publications that are incorporated herein by reference conflicts with the description of this application to the point of making a term unclear, this description shall take precedence.

[0184] The present invention will, for now, be illustrated by the following examples, which are not intended to be limiting. EXAMPLES Materials and methods

[0185] All starting materials used in the examples are commercially available. Example 1 Potentiometry method to determine Rp

[0186] A Titrand 808 was used to determine the weight ratio (Rp) [% by weight (SiO2) / % by weight (Na₂O)]. The device was equipped with an Ag / AgCl reference electrode in 3 M KCl and a tungsten working electrode. Each Rp was measured in duplicate and the Rp values ​​presented are the average of the two measurements. Petition 870250080266, dated 08 / 09 / 2025, page 48 / 358 39 / 63

[0187] 0.5 g of sample was weighed and made up to 30 ml of demineralized water. The titration solution was a 0.1 N HCl solution. The volume V1 (ml) was determined as the equivalence point of the titration. After the equivalence point, 0.5 ml of titration solution was added.

[0188] Subsequently, 50 ml of KF solution (50 g / l of KF in a water / ethanol solution (50 / 50)) were added and allowed to react for 3 minutes. Then, 15 ml of 0.1 N HCl solution were added. The excess HCl was titrated with a 1 N NaOH solution and the volume V2 (ml) was the equivalent point of the titration. Rp was then calculated using the formula below: Rp = (0.31*V1 ) / (1.5(15*1 -V2*1) +(0.5*0.1)) Purity assay analysis to determine SiO2 content.

[0189] 1 g of sample was ignited on a tared platinum plate at 1000 °C for 1 hour, cooled in a desiccator, and weighed. The resulting solid was moistened with water, and 10 ml of hydrofluoric acid were added in small increments. The mixture was then evaporated in a steam bath until dry and then cooled. 10 ml of hydrofluoric acid and 0.5 ml of sulfuric acid were slowly added until all the acids became volatile. The sample was then ignited at 1000 °C, cooled in a desiccator, and then weighed. The ratio of the difference between the final weight and the weight of the initially ignited portion, on the one hand, and the weight of the original sample, on the other hand, represented the weight percent of SiO2. Carbon-sulfur analysis (C / S method) to determine carbon content.

[0190] A 200 mg sample was analyzed on a Horiba EMIA 320V2. Iron and tin spheres, Lecocel®, were used as combustion accelerators. CS26 - 3.19% was used to calibrate the sensor. Possible pretreatment of precipitated silica

[0191] When precipitated silica is in a highly agglomerated form, such as granules, a pretreatment is performed before applying the CTAB surface area determination method to deagglomerate it. Petition 870250080266, dated 08 / 09 / 2025, page 49 / 358 40 / 63 the granules in order to obtain a sample of precipitated silica in the form of a powder.

[0192] Samples of precipitated silica in the form of highly agglomerated particles, especially in the form of granules, were gently ground using a manual agate mortar and pestle, applying gentle pressure and friction to the precipitated silica samples in order to break up the agglomerates and other fragments contained therein. Grinding was carried out for a sufficient duration to give the samples a visually homogeneous consistency that was that of a powder; this duration was generally a few tens of seconds and generally did not exceed 1 minute.

[0193] No pretreatment is required when the precipitated silica is in powder form or in the form of microbeads. N-hexadecyl-N,N,N-trimethylammonium bromide (CTAB) method for determining specific surface area.

[0194] The specific surface area values ​​of CTAB (Sctab) were determined according to the subsequent method derived from the NF ISO 5794-1 standard, appendix G. The method was based on the adsorption of CTAB on the “outer” surface of SiO2 particles.

[0195] In the method, CTAB was allowed to be adsorbed onto precipitated silica under magnetic stirring. The precipitated silica and the residual CTAB solution were then separated. The excess unadsorbed CTAB was determined by back titration with sodium bis(2-ethylhexyl)sulfosuccinate salt (hereinafter, “AOT”) using a titroprocessor, with the endpoint being generated by the maximum turbidity of the solution and determined using an optrode. Equipment:

[0196] Metrohm Optrode (wavelength: 520 nm) connected to Metrohm 662 photometer; Metrohm Titrator: Titrino DMS 716; Metrohm Titration Software: Tiamo. Glass beaker (2000 ml); vials Petition 870250080266, dated 09 / 08 / 2025, p. 50 / 358 41 / 63 volumetric flasks (2000 ml); sealed glass bottles (1000 and 2000 ml); disposable beakers (100 ml); micropipette (500 - 5000 μl); magnetic stirring bars with 25 mm disc ends (Ref. VWR 442-9431) for adsorption; magnetic stirring bars (straight) for titration; polycarbonate centrifuge tubes (at least 20 ml), centrifuge (allowing a speed of 10000 rpm); glass containers (30 ml); thermoequilibrium. Preparation of solutions: - Preparation of a 5.5 g / L CTAB solution (buffered at approximately pH 9.6). In a 2000 mL beaker containing approximately 1000 mL of distilled water at 25 °C, the following were added: 54.25 g of boric acid solution ([c] = 4%), 2.60 g of KCl, and 25.8 mL (±0.1 mL) of sodium hydroxide. The resulting solution was stirred for 15 min before adding 11.0 g ± 0.01 g of CTAB powder (99.9% purity, purchased from Merck). After stirring, the solution was transferred to a 2000 mL volumetric flask maintained at 25 °C, and the volume was adjusted to 2000 mL with distilled water. The solution was then transferred to a 2000 ml glass bottle and kept at a temperature not lower than 22 °C to prevent crystallization of CTAB (which occurs at 20 °C). - Preparation of AOT solution. Approximately 1200 ml of distilled water in a 2000 ml beaker were heated to 35 °C under magnetic stirring. 3.7038 g of AOT (98% purity, purchased from Aldrich) were added. The solution was then transferred to a 2000 ml volumetric flask and allowed to cool to 25 °C. The volume was adjusted to 2000 ml with distilled water and the solution was transferred to two 1000 ml glass bottles, which were stored at 25 °C in a dark place.

[0197] All equipment and solutions were kept at 25 °C during the analysis. Procedure at the beginning and end of each experiment.

[0198] Start of experiment: the solutions were shaken before use. The dosing device was purged before use. At least Petition 870250080266, dated 09 / 08 / 2025, p. 51 / 358 42 / 63 ml of AOT were passed through the device to ensure that the device was clean and that all air bubbles were removed.

[0199] End of experiment: the dosing device was purged to remove the AOT solution. The optrode was cleaned and soaked in distilled water. Determining the gross piece factor

[0200] The variation in the concentrations of AOT and CTAB solutions over time is corrected by determining a daily “gross piece factor”, called the ratio R1=V1 / m1.

[0201] In a 100 ml disposable beaker: 4.9000 g ± 0.0100 g of the 5.5 g / l CTAB solution (m1) were accurately weighed. The tare was set and 23.0000 g ± 1.0000 g of distilled water (Mwater) were accurately added. The solution was stirred using a magnetic stirrer at 500 rpm in the dosing device and the titration was started. The stirring speed must be strictly constant throughout the titration, without generating too many air bubbles.

[0202] V1 is the endpoint volume of AOT solution that is required to titrate the CTAB m1 solution.

[0203] The determination of R1 is performed at least in duplicate. If the standard deviation of R1=V1 / m1 exceeds 0.010, the titration is repeated until the standard deviation is less than or equal to 0.010. The daily ratio R1 is calculated as the average of the 2 or 3 measurements.

[0204] The optrode should be washed with distilled water after each measurement and dried with absorbent paper. Adsorption of CTAB on precipitated silica

[0205] The moisture content (% H2O) for each precipitated silica sample was determined using a thermoequilibrium (temperature: 160 °C) before the adsorption step occurred as follows: tare the balance with an aluminum cup; weigh approximately 2 g of precipitated silica and distribute the powder evenly in the cup, close the balance; observe the moisture percentage. Petition 870250080266, dated 08 / 09 / 2025, page 52 / 358 43 / 63

[0206] In a 100 ml disposable beaker, 0.0100 g of precipitated silica (m0) was accurately weighed. Then, 50.0000 ml + 1.0000 ml of CTAB stock solution (V0) were added. The total mass was recorded. The suspension was stirred for 40 minutes ± 1 minute on a stirring plate at 450 rpm using magnetic stirring bars with disc ends. After 40 minutes, the sample was removed from the stirring plate.

[0207] 25 to 50 ml of the suspension were transferred to a centrifuge tube (the volume depends on the size of the centrifuge tube) and centrifuged for 35 minutes at a speed of 10000 rpm at 25 °C. After centrifugation, the tube was carefully removed from the centrifuge so as not to destabilize the precipitated silica. 10 to 20 ml of CTAB solution were transferred to a glass container which was then stoppered and kept at 25 °C. CTAB solution titration

[0208] In a 100 ml disposable beaker: 4.0000 g ± 0.0100 g of CTAB solution at unknown concentration (m2) were accurately weighed. The tare was set and 19.4000 g ± 1.0000 g of distilled water (Mwater) were added. The solution was placed under agitation at 500 rpm in the dosing device and the titration with the AOT solution was started.

[0209] V2 is the AOT endpoint volume required to titrate a quantity m2 of CTAB solution. The surface area of ​​CTAB, Sctab, is calculated as follows: Ri — R2 Vo Sctab = -----------x [CTAB]ix 578.435 x ---Ri Month where: Sctab = surface area of ​​precipitated silica (including moisture content correction) [m2 / g] R1 = V1 / m1; m1 = mass of CTAB stock solution titrated as the gross piece (kg); Petition 870250080266, dated 08 / 09 / 2025, page 53 / 358 44 / 63 V1 = AOT endpoint volume required to titrate ml of CTAB stock solution as the gross piece (l) R2 = V2 / m2; m2 = mass of the CTAB solution titrated after adsorption and centrifugation (kg); V2 = AOT endpoint volume required to titrate m2 of CTAB stock solution after adsorption and centrifugation (l) [CTAB]i = concentration of CTAB stock solution (g / l) V0 = volume of CTAB stock solution used for adsorption on precipitated silica (l) Mes = solid content of precipitated silica used for adsorption (g) corrected for moisture content, which occurs as follows: Mes = m0 x (100 - % H2O) / 100 Where m0 = initial mass of precipitated silica (g). Determination of specific surface area

[0210] The specific surface area of ​​BET, Sbet, was determined according to the Brunauer-Emmett-Teller (BET) method, as detailed in standard NF ISO 5794-1, appendix E (June 2010) with the following adjustments: the sample was pre-dried at 160 °C±10 °C; the partial pressure used for the P / P0 measurement was between 0.05 and 0.2. Determination of particle size distribution and particle size by centrifugal sedimentation in a disc centrifuge using a centrifugal photosedimentometer (CPS).

[0211] The d50, d16, d84, FWHM and Ld values ​​were determined by centrifugal sedimentation in a disc centrifuge using a “CPS DC 24000UHR” type centrifugal photosedimentometer, marketed by CPS Instruments. This instrument is equipped with operating software supplied with the device (operating software version 11g).

[0212] Instruments used: For the measurement requirement, the following materials and products were used: Ultrasound system: 1500 W Sonics Vibracell VC1500 / VCX1500 generator equipped with a 19 mm probe. Petition 870250080266, dated 08 / 09 / 2025, page 54 / 358 45 / 63 (Converters: CV154+ Boosters (Part No: BHNVC21) + 19 mm probe (Part No: 630-0208)).

[0213] Analytical balance with 0.1 mg precision (e.g., Mettler AE260); Syringes: 1.0 ml and 2.0 ml with 0.9 mm needles (20 ga); 50 ml tall glass beaker (SCHOTT DURAN: 38 mm diameter, 78 mm height); magnetic stirrer with 2 cm stirring bar; vessel for ice bath during sonication.

[0214] Chemicals: deionized water; 96% ethanol; 99% sucrose; dodecane, all from Merck; PVC reference standard from CPS Instrument Inc.; the maximum peak of the reference standard used must be between 200 and 600 nm (e.g., 237 nm). Preparation of the disc centrifuge

[0215] For the measurements, the following parameters were established (see Table 1). For the standard calibration parameters, the PVC reference information provided by the supplier was used. Table 1 Sample Parameters: max. diameter pm 0.79, min. diameter pm 0.02, particle density g / ml 2.11, particle refractive index 1.46, particle absorption K 0.001, non-sphericity factor 1. Calibration Standard Parameters: peak diameter nm 237 Petition 870250080266, dated 08 / 09 / 2025, page 55 / 358 46 / 63 Half-height peak width pm 0.023 Particle density 1.385 Fluid Parameters Fluid density g / ml 1.051 Fluid refractive index 1.3612 Fluid viscosity mPa-s (cpsx) 1.28 xcps=centipoise System configuration

[0216] The measurement wavelength was set to 405 nm. The following runtime option parameters were established (Table 2): Table 2 Baseline Force: Yes Correct for No Stokes: No Extra Software Noise Filtering: No Baseline Deviation Display: Show Calibration Method: External Samples per Calibration: 1

[0217] All other software options are left as defined by the instrument manufacturer. Preparation of the disc centrifuge Petition 870250080266, dated 08 / 09 / 2025, page 56 / 358 47 / 63

[0218] The centrifuge disc is rotated at 24000 rpm for 30 min. The sucrose density gradient (CAS No. 57-50-1) is prepared as follows: In a 50 ml beaker, a 24% by weight aqueous sucrose solution is prepared. In a separate 50 ml beaker, an 8% by weight aqueous sucrose solution is prepared. Once these two solutions are separately homogenized, samples are taken from each solution using a 2 ml syringe which is injected into the rotating disc in the following order: Sample 1: 1.8 ml of the 24% by weight solution. Sample 2: 1.6 ml of the 24% by weight solution + 0.2 ml of the 8% by weight solution Sample 3: 1.4 ml of the 24% by weight solution + 0.4 ml of the 8% by weight solution Sample 4: 1.2 ml of the 24% by weight solution + 0.6 ml of the 8% by weight solution Sample 5: 1.0 ml of the 24% by weight solution + 0.8 ml of the 8% by weight solution Sample 6: 0.8 ml of the 24% by weight solution + 1.0 ml of the 8% by weight solution Sample 7: 0.6 ml of the 24% by weight solution + 1.2 ml of the 8% by weight solution Sample 8: 0.4 ml of the 24% by weight solution + 1.4 ml of the 8% by weight solution Sample 9: 0.2 ml of the 24% by weight solution + 1.6 ml of the 8% by weight solution Sample 10: 1.8 ml of the 8% by weight solution.

[0219] Before each injection into the disc, the two solutions are homogenized in the syringe by aspirating about 0.2 ml of air followed by brief manual agitation for a few seconds, taking care not to lose any liquid. Petition 870250080266, dated 08 / 09 / 2025, page 57 / 358 48 / 63

[0220] These injections, with a total volume of 18 ml, are intended to create a density gradient useful for eliminating certain instabilities that may arise during the injection of the sample to be measured. To protect the density gradient from evaporation, 1 ml of dodecane was added to the rotating disc using a 2 ml syringe. The disc is then left to rotate at 24000 rpm for 60 minutes before any first measurement. Sample preparation

[0221] The sample was prepared and analyzed according to the current protocol, that is: PE = 3.2 g / 40 ml of H2O - suspension subjected to ultrasound at 1500 W for 8 minutes in a refrigerated environment (ice bath) 100 pl of sample taken - disc rotation at 24000 rpm - analysis time of 20-25 minutes.

[0222] 3.2 g of silica in a 50 ml tall glass beaker (SCHOTT DURAN: 38 mm diameter, 78 mm height) were weighed and 40 ml of deionized water were added to obtain an 8 wt% precipitated silica suspension. The suspension was stirred with a magnetic stirrer (minimum 20 s) before placing the beaker in a crystallization dish filled with ice and cold water. The magnetic stirrer was removed and the crystallization plate was placed under the ultrasonic probe positioned 1 cm from the bottom of the beaker. The ultrasonic probe was set to 56% of its maximum amplitude and activated for 8 min. At the end of sonication, the beaker was again placed on the magnetic stirrer with a 2 cm magnetic stirring bar stirring at least 500 rpm until after sampling.

[0223] The ultrasonic probe must be in proper working condition. At least one of the following checks, preferably both, must be performed: (i) visual verification of the physical integrity of the probe tip (roughness depth less than 2 mm measured with a fine caliper); (ii) verification that the measured d50 of commercial Zeosil® 1165MP precipitated silica is 93 nm ±3 nm. If results are negative, a new probe must be used. Petition 870250080266, dated 09 / 08 / 2025, p. 58 / 358 49 / 63 Analysis

[0224] Before each sample was analyzed, a calibration standard was registered. In each case, 0.1 ml of the PVC standard provided by CPS Instruments, whose characteristics were previously entered into the software, was injected. It is important to start the measurement in the software simultaneously with this first injection of the PVC standard. Confirmation from the device must be received before injecting 100 μL of the previously sonicated sample, ensuring that the measurement starts simultaneously with the injection.

[0225] These injections were made with 2 clean 1 ml syringes. At the end of the measurement, which is reached at the end of the time required for all smaller diameter particles to settle (set in the software to 0.02 pm), the ratio for each diameter class was obtained. The resulting curve is called the aggregate size distribution. Results

[0226] The values ​​of d50, di6, d84 and Ld are based on distributions developed on a linear scale. Integrating the particle size distribution function of the diameter allows obtaining a “cumulative” distribution, that is, the total mass of particles between the minimum diameter and the diameter of interest. d50: is the diameter below and above which 50% by mass of the SiO2 particle population is found. The d50 is called the average size, which is the average diameter of the precipitated silica. d84: is the diameter below which 84% of the total mass of the particles is measured. di6: is the diameter below which 16% of the total mass of the particles is measured. Ld: is calculated according to the equation: Ld=(d84-di6) / d50 Determination of pore volume and pore size by mercury (Hg) porosimetry Petition 870250080266, dated 08 / 09 / 2025, page 59 / 358 50 / 63

[0227] Pore volume and pore size distribution were determined using a Micromeritics AutoPore® IV 9520 porosimeter; they were calculated using the Washburn relationship with a theta contact angle of 140° and a surface gamma tension of 485 g-cm / s2 (dynes / cm). Each sample was dried before measurement in an oven at 200 °C for 2 hours under atmospheric pressure. The initial weight of precipitated silica placed in the type 10 penetrometer, which has a precision of 0.001 g, was selected for good measurement reproducibility, so that the rod volume used, i.e., the percentage volume of mercury (Hg) consumed for the penetrometer load, was 40% to 80%. The penetrometer was then slowly evacuated to 50 pm Hg and maintained at this pressure for 5 min.

[0228] The AutoPore® instrument was operated using software version IV 1.09. No corrections were made to the raw data. The measurement range was 3.59 kPa (0.52 psi) to 413685 kPa (60000 psi), and at least 100 measurement points were used (19 measurement points from 3.59 kPa (0.52 psi) to 193 kPa (28 psi) with a 10-second equilibration time, and then 81 points from 1.93 kPa (0.28 psi) to 413685 kPa (60000 psi) with a 20-second equilibration time). If appropriate, the software introduced additional measurement points if the incremental intrusion volume was >0.5 ml / g. The intrusion curve was smoothed using the smooth differentials function of the instrument software.

[0229] Differential intrusion data in log (ml / g) versus pore size were analyzed in the pore diameter range of 3.5 nm to 5 pm. Example 1 - Precipitated silica from ex-sand (comparative)

[0230] A reference precipitated silica was produced from a sodium silicate obtained from sand (ex-sand sodium silicate).

[0231] The characteristics of ex-sand sodium silicate (S0) used for this reaction (impurity profile and element composition) are shown. Petition 870250080266, dated 08 / 09 / 2025, page 60 / 358 51 / 63 in Table 3 below. The Rp value of sodium silicate was obtained using the potentiometry method described above.

[0232] 17 l of purified water and 0.260 kg of exodium sodium sulfate S0 were introduced into a 25 l stainless steel reactor. The resulting solution was heated to 92 °C. The entire reaction was carried out at this temperature. 80 g / l of sulfuric acid were introduced under stirring (350 rpm, stirring with a TT mixel) until the pH reached a value of 4.1.

[0233] Simultaneously, a sodium silicate solution with a SiO2 / Na2O weight ratio of 3.5 and a concentration of 230 g / l and sulfuric acid with a concentration of 80 g / l were introduced into the reactor for a period of 10 minutes, with the sodium silicate solution being introduced at a flow rate of 107 g / min and the sulfuric acid being introduced at a flow rate regulated in such a way as to maintain the pH of the reaction medium at a value of 4.1.

[0234] At the end of 10 minutes, the sodium silicate flow rate was kept constant. The 80 g / l sulfuric acid was replaced by the introduction of sulfuric acid at a concentration of 1710 g / l for a period of 16 min and at a flow rate that allows maintaining the pH of the reaction medium at a value of 4.1.

[0235] The addition of sulfuric acid was then stopped. Sodium silicate was introduced at a flow rate of 107 g / min as long as the pH of the reaction medium was below 8.0.

[0236] The pH of the reaction medium was then maintained at 8.0 for 18 minutes by simultaneous addition of sodium silicate at a flow rate of 167 g / min and sulfuric acid with a concentration of 1710 g / l at a regulated flow rate that allows the pH to be maintained.

[0237] Finally, at the end of this simultaneous addition, the reaction medium was brought to a pH of 4.0 by adding sulfuric acid at a concentration of 1710 g / l. The medium was matured for 10 minutes at this pH. Petition 870250080266, dated 08 / 09 / 2025, page 61 / 358 52 / 63

[0238] The fluid paste thus obtained was filtered and washed through a filter press (20% dry cake extract). The resulting cake was then mechanically broken and the resulting fluid paste was dried using a spray dryer. The characteristics of the precipitated silica thus obtained (precipitated silica P0) are shown in Tables 3 and 4 below. Example 2 - Washed ex-RHA precipitated silica (comparative)

[0239] A reference precipitated silica was produced from a sodium silicate obtained from washed rice husk ash (RHA) (ex-RHA washed sodium silicate). Initial characteristics of RHA:

[0240] Rice husk ash (RHA) was used, which has the following characteristics: - The SiO2 concentration was measured using the ASSAY purity method, as described above: 88.3% by weight vs. total sample; - The carbon content was analyzed by C / S, as described above: 4.9% by weight vs. total sample. RHA washing:

[0241] 1000 g of a sulfuric acid solution at a concentration of 0.05% by weight, and 50 g of RHA were introduced into a reactor under agitation.

[0242] The mixture was kept under stirring and heated to 70 °C for 30 minutes. At the end of the 30 minutes, the RHA and the acidified water mixture were separated by Büchner filtration to concentrate the solid before dissolution. Dissolution of RHA:

[0243] In a 316 l stainless steel autoclave reactor at 5 l, the following reagents were introduced: - 290 g of a soda solution with a concentration of 397 g / l; - 1164 g of RHA and - 2560 g of demineralized water. Petition 870250080266, dated 09 / 08 / 2025, p. 62 / 358 53 / 63

[0244] The reaction mixture was kept under agitation at 500 rpm with a TT mixel stirrer.

[0245] The temperature of the mixture was then raised to 160 °C using a double jacket and maintained for 3 hours.

[0246] Once the reaction was complete, a solid / liquid separation was performed by centrifugation. The centrifuge is diluted to achieve the target SiO2 concentration and density. The diluted product corresponds to the sodium silicate S1 used for the subsequent silica precipitation step, as described below.

[0247] The characteristics of ex-RHA washed sodium silicate (S1) (elemental composition) are shown in Table 3 below. The Rp of this sodium silicate was analyzed by the potentiometry method described above. Silica preparation:

[0248] 17 L of purified water and 0.260 kg of sodium sulfate S1 were introduced into a 25 L stainless steel reactor. The solution was heated to 92 °C. The entire reaction was carried out at this temperature.

[0249] Sulfuric acid 80 g / l was introduced under stirring (350 rpm, stirring with TT mixel) until the pH reached a value of 4.1.

[0250] Simultaneously, a sodium silicate solution with a SiO2 / Na2O weight ratio of 3.5 and a concentration of 230 g / l and sulfuric acid with a concentration of 80 g / l were introduced into the reactor for a period of 10 minutes, with the sodium silicate solution being introduced at a flow rate of 107 g / min and the sulfuric acid being introduced at a flow rate regulated in such a way as to maintain the pH of the reaction medium at a value of 4.1.

[0251] At the end of 10 minutes, the sodium silicate flow rate was kept constant. The 80 g / l sulfuric acid was replaced by the introduction of sulfuric acid at a concentration of 1710 g / l for a period of 16 min and at a flow rate that allows maintaining the pH of the reaction medium at a value of 4.1. Petition 870250080266, dated 09 / 08 / 2025, p. 63 / 358 54 / 63

[0252] The addition of sulfuric acid was then stopped. Sodium silicate was introduced at a flow rate of 107 g / min until the pH of the reaction medium reached 8.0.

[0253] The pH of the reaction medium was then maintained at 8.0 for 18 minutes by simultaneous addition of sodium silicate at a flow rate of 167 g / min and sulfuric acid with a concentration of 1710 g / l at a regulated flow rate that allows the pH to be maintained.

[0254] Finally, at the end of this simultaneous addition, the reaction medium was brought to a pH of 4.0 by adding sulfuric acid at a concentration of 1710 g / l. The medium was matured for 10 minutes at this pH.

[0255] The fluid paste thus obtained was filtered and washed through a filter press (20% dry cake extract). The resulting cake was then mechanically broken and the resulting fluid paste was dried using a spray dryer. The characteristics of the precipitated silica thus obtained (precipitated silica P1) are shown in Tables 3 and 4 below. Example 3 - Precipitated silica ex-RHA unwashed

[0256] According to the present invention, a precipitated silica was produced from a sodium silicate obtained from unwashed rice husk ash (RHA) (ex-RHA sodium silicate). Initial characteristics of RHA:

[0257] Rice husk ash (RHA) was used, which has the following characteristics: - The SiO2 concentration was measured using the ASSAY purity method, as described above: 88.1% by weight vs. total sample; - The carbon content was analyzed by C / S, as described above: 11% by weight vs. total sample. Dissolution of RHA:

[0258] In a 316 l stainless steel autoclave reactor at 20 l, the following reagents were introduced: - 1682 g of a soda solution with a concentration of 397 g / l; Petition 870250080266, dated 09 / 08 / 2025, p. 64 / 358 55 / 63 - 3700 g of RHA and - 4628 g of demineralized water.

[0259] The reaction mixture was kept under agitation at 800 rpm with a TT mixel stirrer.

[0260] The temperature of the mixture was then raised to 160 °C using a double jacket and maintained for 3 hours.

[0261] Once the reaction was complete, a solid / liquid separation was performed by centrifugation. The centrifuge is diluted to achieve the target SiO2 concentration and density. The diluted product corresponds to the sodium silicate S2 used for the subsequent silica precipitation step, as described below.

[0262] The characteristics of unwashed ex-RHA sodium silicate (S2) (elemental composition) are shown in Table 3 below. The Rp of this sodium silicate was analyzed by the potentiometry method described above. Silica preparation:

[0263] 17 L of purified water and 0.260 kg of sodium sulfate S2 were introduced into a 25 L stainless steel reactor. The solution was heated to 92 °C. The entire reaction was carried out at this temperature.

[0264] Sulfuric acid 80 g / l was introduced under stirring (350 rpm, stirring with TT mixel) until the pH reached a value of 4.1.

[0265] Simultaneously, a sodium silicate solution with a SiO2 / Na2O weight ratio of 3.5 and a concentration of 230 g / l and sulfuric acid with a concentration of 80 g / l were introduced into the reactor for a period of 10 minutes, with the sodium silicate solution being introduced at a flow rate of 107 g / min and the sulfuric acid being introduced at a flow rate regulated in such a way as to maintain the pH of the reaction medium at a value of 4.1.

[0266] At the end of the 10 minutes, the sodium silicate flow rate was kept constant. The 80 g / l sulfuric acid was replaced by the introduction of sulfuric acid at a concentration of 1710 g / l for a period of 16 min and Petition 870250080266, dated 09 / 08 / 2025, p. 65 / 358 56 / 63 at a flow rate that allows maintaining the pH of the reaction medium at a value of 4.1.

[0267] The addition of sulfuric acid was then stopped. Sodium silicate was introduced at a flow rate of 107 g / min as long as the pH of the reaction medium was below 8.0.

[0268] The pH of the reaction medium was then maintained at 8.0 for 18 minutes by simultaneous addition of sodium silicate at a flow rate of 167 g / min and sulfuric acid with a concentration of 1710 g / l at a regulated flow rate that allows the pH to be maintained.

[0269] Finally, at the end of this simultaneous addition, the reaction medium was brought to a pH of 4.0 by adding sulfuric acid at a concentration of 1710 g / l. The medium was matured for 10 minutes at this pH.

[0270] The fluid paste thus obtained was filtered and washed through a filter press (dry cake extract 20%). The resulting cake was then mechanically broken and the resulting fluid paste was dried using a spray dryer. The characteristics of the precipitated silica thus obtained (precipitated silica P2) are shown in Tables 3 and 4 below. Example 4

[0271] The following Table (Table 3) reports the characteristics in terms of impurity profile and elemental composition of ex-sand sodium silicate (S0), ex-RHA washed sodium silicate (S1) and unwashed ex-RHA sodium silicate (S2) used in Examples 1-3. In addition, the characteristics in terms of impurity profile and elemental composition of the corresponding precipitated silica produced according to Examples 1-3 (P0, P1 and P2) are reported.

[0272] Unless otherwise indicated, the quantities in Table 3 are in ppm.

[0273] The amounts in precipitated silica are based on the total weight of precipitated silica. Petition 870250080266, dated 08 / 09 / 2025, page 66 / 358 57 / 63

[0274] In Table 3, the symbol * indicates that the quantities in the silicate solution are based on the total weight of the silicate solution.

[0275] The symbol ** indicates that the quantities in the silicate solution are based on the weight of SiO2.

[0276] From this table, it can be seen that the absence of the washing step mainly impacts the amount of Mn and P. Table 3 Product Rp (-) SiO2 (%) Mn P RHA Washed RHA (100) 1947 409 Unwashed RHA (100) 2948 1805 Silicate* Ex-sand (S0) 3.45 20.0 5 5 Washed Ex-RHA (S1) 3.45 18.8 5 340 Unwashed Ex-RHA (S2) 3.48 20.0 16 560 Silicate** Ex-sand (S0) (100) 25 25 Washed Ex-RHA (S1) (100) 27 1809 Unwashed Ex-RHA (S2) (100) 80 2800 Precipitated silica Ex-sand (P0) (100) 6 6 Washed Ex-RHA (P1) (100) 8 12 Unwashed Ex-RHA (P2) (100) 21 28

[0277] The following table (Table 4) reports the characteristics of the precipitated silica produced according to Examples 1-3 described above. Petition 870250080266, dated 08 / 09 / 2025, page 67 / 358 58 / 63 Table 4 - Surface properties of CTAB, BET, CPS and Hg porosimetry of ex-sand, ex-washed RHA and ex-unwashed RHA precipitated silica samples. Product Precipitated Silica P0 Precipitated Silica P1 Precipitated Silica P2 Characteristics Example 1 - ex-sand Example 2 - ex-washed RHA Example 3 - ex-unwashed RHA CTAB (m2 / g) 197 204 196 BET (m2 / g) 222 220 217 CPS d50 (nm) 110 111 104 Ld (-) 1.8 1.8 1.7 Mode (nm) 72 70 70 Example 5 - Rubber application performance

[0278] Preparation of rubber compounds suitable for tire or tire parts preparation: the process for preparing rubber compounds (i.e., elastomeric compound filled with precipitated silica) was carried out in three successive stages.

[0279] The first and second mixing stages (non-productive stages, NP1 and NP2) consisted of high-temperature thermomechanical work, followed by a third mechanical stage (productive stage, P3) at a temperature below 110 °C. The latter allowed the introduction of the vulcanization system.

[0280] The first and second stages were carried out using a Brabender internal mixer (liquid chamber volume of 380 ml), respectively, with a filling factor of 0.62 and 0.6. The initial temperature and speed of the collectors were fixed, one at a time, in order to achieve mixing drop temperatures of approximately 140-170 °C. Petition 870250080266, dated 08 / 09 / 2025, page 68 / 358 59 / 63

[0281] The duration of the first mixing stage was between 2 and 10 minutes. After cooling the mixture (temperature below 100 °C), the second mixing phase allowed the introduction of the vulcanization system (sulfur and accelerator). This was carried out in an open two-cylinder mill, preheated to 50 °C.

[0282] The duration of this phase was between 2 and 6 minutes.

[0283] The final rubber compound was then calendered into sheets 2-3 mm thick.

[0284] In Table 5, the quantity of each ingredient in the compositions is expressed as phr (parts per hundred of rubber), that is, based on the total quantity of rubber (in this document, sSBR + BR) that is contained in the rubber formulations. Table 5: Rubber formulation Rubber Composition Ingredients F1 F2 S-SBR 80 80 BR 20 20 Precipitated silica P1 - Example 2 80 Precipitated silica P2 - Example 3 80 N330 3.0 3.0 TESPT 10.0 10.0 TDAE 27.5 27.5 Stearic acid 2.0 2.0 Zinc oxide 2.5 2.5 6-PPD 1.9 1.9 Sulfur 1.1 1.1 Petition 870250080266, dated 08 / 09 / 2025, page 69 / 358 60 / 63 CBS 2.0 2.0 DPG 1.5 1.5 SSBR with 21% styrene, 49% functionalized vinyl (Sprintan SLR 4602 from Synthos) BR: Buna CB 25 from Arlanxeo TESPT: (bis-triethoxysilylpropyl)-tetrasulfide, Si69 from Evonik N330: Carbon black TDAE (treated distillate aromatic extract) Vivatec 500 from Hansen & Rosenthal KG 6-PPD: N-1,3-dimethylbutyl-N-phenyl-para-phenylenediamine (Santoflex 6-PPD from Flexsys CBS: N-cyclohexyl-2-benzothiazyl-sulfenamide (Rhenogran CBS-80 from RheinChemie) DPG: Diphenylguanidine (Rhenogran DPG-80 from RheinChemie)

[0285] An evaluation of the rheological properties of the uncured compounds was performed to monitor processability indicators. Once the vulcanization characteristics were determined, the uncured compounds were vulcanized at the ideal vulcanization ratio (T98), and the mechanical and dynamic properties were measured. Viscosity of uncured compositions

[0286] Mooney viscosity was measured at 100 °C using an MV200 rheometer according to standard NF ISO289. After one minute of preheating, the torque value was read at 4 minutes (ML1+4 - 100 °C). The following elements are determined from the torque variation curve as a function of time: - the minimum torque (Tmin), which reflects the viscosity of the composition at the temperature under consideration; - the maximum torque (Tmax); Petition 870250080266, dated 09 / 08 / 2025, p. 70 / 358 61 / 63 - the torque delta (ΔT = Tmax - Tmin), which reflects the degree of crosslinking caused by the action of the crosslinking system and, if necessary, the coupling agents; - T.90%, corresponding to the time required to reach 90% of the maximum torque; - the pre-vulcanization time TS2, corresponding to the time required to achieve a 2-point increase above the minimum torque at the temperature under consideration, and which reflects the time during which it is possible to process the raw mixtures at that temperature without the onset of vulcanization (the mixture cures from TS2). The results obtained are shown in Table 6. Mechanical properties of cured compositions

[0287] The Shore A hardness measurement of the cured compositions (vulcanization time T98 at 160 °C) was performed according to the ASTM D 2240 standard. The values ​​were measured after 3 seconds.

[0288] Uniaxial tensile tests were performed according to the NF ISO 37 standard with H2 specimens at a speed of 500 m / min in an INSTRON 5564 device. The M100 and M300 moduli (obtained at 100% and 300% strains, respectively) and tensile strength (TS) are expressed in MPa; elongation at break (EB) is expressed as a percentage. A reinforcement index (RI) is calculated, defined as the ratio between the modulus obtained at 300% strain and that obtained at 100% strain.

[0289] The measured properties are reported in Table 7. Dynamic properties of curated compositions

[0290] The dynamic properties were measured on a viscoanalyzer (METRAVIB DMA+1000) according to the ASTM D5992 standard.

[0291] Dynamic response of cured composites under strain sweep conditions: parallelepiped specimens (8 mm2 cross-section and 4 mm height) were subjected to alternating double shear sinusoidal deformation at a temperature of 40 °C and a frequency Petition 870250080266, dated 08 / 09 / 2025, page 71 / 358 62 / 63 of 10 Hz according to a round-trip cycle time in the range of 0.1% to 50% for the forward cycle and 50% to 0.1% for the return cycle. The values ​​of the maximum loss factor (Tan δ max), the shear storage modulus (G'0.1% and G*12%) and the Payne effect (G'0.1% - G50%) were recorded during the return cycle. The measured properties are reported in Table 8. Dynamic response of cured compositions under temperature sweep conditions

[0292] The dynamic response of vulcanized rubber compositions is measured by subjecting parallelepiped specimens (8 mm² cross-section and 7 mm height) to a temperature sweep from -70 °C to 100 °C (temperature rise rate +5 °C / min), under alternating double shear sinusoidal deformation of 1% and at a frequency of 10 Hz. The maximum loss factor (Tan δ max) is then measured. Table 6 - Not cured F1 (average) F2 (average) Torque delta (ΔΤ) dN-m 56.1 55.8 TS2 min 3.8 4.0 T.90 % min 18.8 18.7 Mooney viscosity - ML (1+4) MU 92 90 Table 7 - Mechanical / cured properties F1 (average) F2 (average) Hardness ShA - 3 s pts 67 68 Modulus 300 MPa 17.2 15.9 R1=M300 / M100 - 4.2 4.3 Petition 870250080266, dated 08 / 09 / 2025, page 72 / 358 63 / 63 Tensile strength (TS) MPa 19.7 18.6 Elongation at break (EB) % 332 337 EB x TS MPa 6552 6260 Table 8 - Dynamic / cured properties F1 (average) F2 (average) Traction mode (0.089 %) Tan δ max - 0.637 0.672 Temperature in Tan δ max °C -21 -20 Tan δ at 0 °C - 0.337 0.355 E' at 0 °C Pa 3.3E+07 3.0E+07 E' at 40 °C Pa 1.4E+07 1.2E+07 Tan δ at 60 °C - 0.108 0.107 E* at 60 °C Pa 1.1E+07 1.0E+07 Shear mode ΔG' - 40 °C MPa 2.7 2.7 Tan δ max - 40 °C - 0.226 0.223 G* at 12 % - 40 °C MPa 1.9 1.8

[0293] The above results demonstrate that rubber compositions comprising precipitated silica obtained by the process according to the present invention (i.e., unwashed ex-RHA) advantageously exhibit mechanical and dynamic properties similar to rubber compositions comprising precipitated silica obtained by pre-washing rice husk ash (i.e., washed ex-RHA). Petition 870250080266, dated 09 / 08 / 2025, p. 73 / 358

Claims

1 / 6 CLAIMS 1. Process for producing precipitated silica from vegetable ash, said process being characterized by comprising the steps of: (I) reacting vegetable ash containing SO2 and manganese in a weight amount, expressed as elemental manganese, of at least 10 ppm, based on the weight of SO2 contained in the vegetable ash, with an alkali metal base, preferably an alkali metal hydroxide, at a temperature of at least 100 °C in an aqueous reaction medium, so as to obtain an aqueous silicate solution comprising (i) SiO2 in the form of silicate anions and (ii) manganese in a weight amount, expressed as elemental manganese, of at least 10 ppm, based on the weight of SiO2 contained in the silicate solution, and (II) reacting the aqueous silicate solution with an acidifying agent at a temperature of at least 40 °C in an aqueous reaction medium having a pH exceeding 7.0 during at least part of the reaction duration,in order to achieve SiO2 precipitation and produce an aqueous fluid paste comprising particulate SiO2 and manganese in a weight amount, expressed as elemental manganese, of at least 10 ppm, based on the weight of SiO2 contained in the aqueous fluid paste, and said process further optionally comprising a step (A), prior to step (I), of burning a plant and / or a part of a plant containing SiO2 and manganese in a weight amount, expressed as elemental manganese, of at least 10 ppm, based on the weight of SiO2 contained in the plant and / or part of a plant, in order to obtain vegetable ash. Petition 870250080266, dated 09 / 08 / 2025, p. 74 / 358 2 / 6, 2. Process according to claim 1, said process being characterized by further comprising step (A), said process being free of any step (B), after step (A) and before step (I), of removing part or all of the manganese and, when present, part or all of the phosphorus from the vegetable ash, and said process being free of any step (B'), before step (A), of removing part or all of the manganese and, when present, part or all of the phosphorus from the plant and / or part of the plant.

3. Process, according to claim 1 or 2, characterized in that the vegetable ash contains manganese in an amount by weight, expressed as elemental manganese, of at least 500 ppm, more preferably at least 1000 ppm, and most preferably at least 2000 ppm, based on the weight of SiO2 contained in the vegetable ash.

4. A process according to any one of claims 1 to 3, characterized in that the vegetable ash contains manganese in an amount by weight, expressed as elemental manganese, of at most 15000 ppm, preferably at most 12000 ppm, more preferably at most 9000 ppm, even more preferably at most 7000 ppm, even more preferably at most 5000 ppm and most preferably at most 3500 ppm, based on the weight of SiO2 contained in the vegetable ash.

5. Process, according to any one of claims 1 to 4, characterized in that the aqueous silicate solution contains manganese in an amount by weight, expressed as elemental manganese, of at least 10 ppm, preferably at least 30 ppm and more preferably at least 50 ppm, based on the total weight of SiO2 contained in the aqueous silicate solution. Petition 870250080266, dated 09 / 08 / 2025, p. 75 / 358 3 / 6 6. A process according to any one of claims 1 to 5, characterized in that the aqueous silicate solution contains manganese in an amount by weight, expressed as elemental manganese, of at most 500 ppm, preferably at most 375 ppm, more preferably at most 250 ppm, even more preferably at most 200 ppm, even more preferably at most 150 ppm and most preferably at most 100 ppm, based on the weight of SiO2 contained in the aqueous silicate solution.

7. A process according to any one of claims 1 to 6, characterized in that the vegetable ash contains phosphorus in an amount by weight, expressed as elemental phosphorus, of at least 500 ppm, preferably at least 1000 ppm, more preferably at least 1500 ppm, and even more preferably at least 1650 ppm, at least 1700 ppm or at least 1750 ppm based on the weight of SiO2 contained in the vegetable ash.

8. A process, according to any one of claims 1 to 7, characterized in that the vegetable ash contains phosphorus in an amount by weight, expressed as elemental phosphorus, of at most 5000 ppm, preferably at most 3500 ppm, more preferably at most 3000 ppm, even more preferably at most 2500 ppm and most preferably at most 2000 ppm based on the weight of SiO2 contained in the vegetable ash.

9. Process, according to any one of claims 1 to 8, characterized in that the aqueous silicate solution contains phosphorus in an amount by weight, expressed as elemental phosphorus, of at least 500 ppm, preferably at least 1000 ppm, more preferably at least 1500 ppm, even more preferably at least 1650 ppm, at least 1700 ppm, or at least 1750 ppm, even more preferably at least 2000 ppm and most preferably at least 2500 ppm based on the weight of SiO2 contained in the aqueous silicate solution.

10. A process according to any one of claims 1 to 9, characterized in that the aqueous silicate solution contains phosphorus in an amount by weight, expressed as elemental phosphorus, of at most 5000 ppm, preferably at most 3500 ppm, more preferably at most 3000 ppm, based on the weight of SiO2 contained in the aqueous silicate solution.

11. Process according to any one of claims 1 to 10, characterized by further comprising the steps of: (III) filtering the aqueous fluid paste obtained after step (II), preferably using a filter press, so as to obtain a filter cake comprising particulate SiO2, (IV) optionally washing the filter cake with a liquid containing water, (V) liquefying the filter cake into a fluidizable aqueous suspension comprising particulate SiO2 by adding a liquid containing water to the filter cake, and optionally further subjecting the filter cake to mechanical and / or chemical treatment, and (VI) drying the fluidizable aqueous suspension, preferably by means of a spray dryer, so as to obtain precipitated silica.

12. Process, according to claim 11, characterized by being free of any step (B''), after step (VI), of removing part or all of the manganese and, when present, phosphorus from the precipitated silica. Petition 870250080266, dated 08 / 09 / 2025, page 77 / 358 5 / 6 13. A process, according to any of the preceding claims, characterized in that the precipitated silica produced contains particulate SiO2 and manganese in an amount by weight, expressed as elemental manganese, ranging from 10 ppm to 75 ppm, based on the weight of SiO2 contained in the precipitated silica.

14. Precipitated silica characterized by containing SO2 in particulate form and manganese in a weight quantity, expressed as elemental manganese, ranging from 10 ppm to 75 ppm, based on the weight of SiO2 contained in the precipitated silica.

15. Precipitated silica, according to claim 14, characterized by containing manganese in an amount by weight, expressed as elemental manganese, of at least 15 ppm and preferably at least 18 ppm, based on the weight of SO2 contained in the precipitated silica.

16. Precipitated silica, according to claim 14 or 15, characterized by containing manganese in an amount by weight, expressed as elemental manganese, of no more than 50 ppm, preferably no more than 30 ppm and more preferably no more than 25 ppm, based on the total weight of SiO2 contained in the precipitated silica.

17. Precipitated silica, according to any one of claims 14 to 16, characterized by containing phosphorus in an amount by weight, expressed as elemental phosphorus, of at least 10 ppm, preferably at least 15 ppm, more preferably at least 20 ppm, and even more preferably at least 23 ppm, based on the weight of SiO2 contained in the precipitated silica.

18. Precipitated silica, according to any one of claims 14 to 17, characterized by containing phosphorus in a weight quantity, expressed as elemental phosphorus, of no more than 300 ppm, preferably no more than 100 ppm, more preferably no more than 50 ppm and even more preferably no more than 30 ppm, based on the weight of SiO2 contained in the precipitated silica.

19. Use of precipitated silica as defined in any one of claims 14 to 18 characterized by being intended for the manufacture of at least one of (i) an elastomeric composition filled with precipitated silica; (ii) a tire part comprising an elastomeric composition filled with precipitated silica; and (iii) a tire comprising at least one part comprising an elastomeric composition filled with precipitated silica. Petition 870250080266, dated 08 / 09 / 2025, p. 79 / 358