Process for preparing a catalyst by selective extraction from a contaminated catalyst

Abstract

A process for producing a catalyst comprising a metal from group VIB and / or a metal from group VIII, and a support based on oxide(s), said process comprising recycling the metal from group VIB and / or group VIII from a source catalyst comprising a metal from group VIB and / or VIII common with the catalyst to be produced, said source catalyst being contaminated, in particular with arsenic, the process comprising: - an extraction of the metal from group VIB and / or the metal from group VIII of said source catalyst by an extraction solution comprising an organic compound having complexing properties to obtain a solution of extracted metal(s), then - an impregnation of the support with an impregnation solution from said solution of extracted metal(s), to obtain an impregnated substrate, said extracted metal(s) remaining in liquid phase from extraction until impregnation.

Description

Title of the invention: Process for preparing a catalyst by selective extraction from a contaminated catalyst. Technical field

[0001] The present invention relates to the recycling of catalyst metals, particularly those from hydrocarbon hydrotreating or hydroconversion units, for the purpose of manufacturing catalysts. More specifically, the present invention relates to a catalyst preparation process involving a step of extracting the desired metals from a contaminated catalyst. It relates in particular to a catalyst preparation process involving a step of extracting the desired metals from an arsenic-contaminated catalyst while limiting arsenic extraction. The extraction solution is then used as an impregnation solution to prepare a catalyst. The catalyst thus obtained is intended, in particular, for use in hydrocarbon hydrotreating or hydroconversion units. Previous technique

[0002] Most of the technological innovations needed for the energy transition (electric vehicles, wind power, fuel cells, batteries, etc.) require the massive use of metals. In order to meet this demand while ensuring sustainable development, metal recycling is becoming a major challenge for the coming century.

[0003] In particular, spent catalysts from hydrocarbon hydrotreating or hydroconversion units contain metals of interest, namely at least one metal from group VIB and / or at least one metal from group VIII. Once spent, the metals contained in these catalysts are not currently recycled for the manufacture of new catalysts: they are essentially reused for the manufacture of special alloys, requiring complex purification operations, in particular to remove from the recovered metals compounds considered contaminating, such as arsenic, or problematic with regard to the intended applications, such as phosphorus, the presence of which disrupts, for example, the properties of chromium steel alloys.

[0004] However, processes have been developed to recover the metals from the catalysts, in order to recycle them for the manufacture of new catalysts.

[0005] For example, US patent application 2007 / 0167321 proposes to recover molybdenum from spent catalysts to make new catalysts. To do this, according to this process, the spent catalyst is dispersed in a basic solution, a contaminant / compound contained in the spent catalyst that one wishes to eliminate (arsenic, phosphorus) is removed from the solution by precipitating it, and then the solution is filtered. Next, the molybdenum is precipitated by modifying the pH of the solution towards an acidic pH. The molybdenum precipitate is filtered so that it can be reused by dispersion in an impregnation solution also containing precursors of other metals, such as precursors of cesium, antimony or vanadium, and other components necessary to constitute the new catalyst by impregnating a support.

[0006] French patent application FR3117381 proposes the production of a recycled catalyst for the hydrotreating or hydroconversion of hydrocarbons. Group VIII and Group VIB metals are extracted using an aqueous solution containing at least one organic compound with complexing properties, and optionally also acidic. The resulting solution is then used directly for impregnation onto an oxide support to produce a recycled catalyst; that is, the extracted metals remain in the liquid phase throughout the entire process. Unlike prior techniques, this process does not attempt to recover the metal in solid, monometallic form, thus avoiding numerous precipitation / filtration operations. The process is therefore easy to implement on an industrial scale.

[0007] During operation in a hydrotreating or hydroconversion process, a catalyst becomes deactivated by the accumulation of coke and / or sulfur compounds and / or other contaminants on its surface. These contaminants originate, among other sources, from the feedstock. The most common contaminants are metals such as nickel, vanadium, iron, and titanium, but also silicon, calcium, sodium, potassium, chlorine, and arsenic. While poisoning by coke, for example, is reversible, poisoning by metals, on the other hand, can lead to structural changes and irreversible deactivation of the catalyst. The most prevalent metals in crude oils and heavy feedstocks are vanadium and nickel. These metals are generally less abundant in lighter feedstocks.However, several studies have shown the detrimental influence of even small amounts of arsenic on the lifespan of hydrotreating and / or hydroconversion catalysts. Arsenic-containing organic compounds react rapidly under hydrotreating conditions, decomposing and adsorbing onto the catalyst surface. Arsenic is therefore often the most problematic contaminant in a hydrotreating and / or hydroconversion catalyst.

[0008] When extracting metals from a contaminated catalyst to use the resulting solution directly for impregnation onto a support to produce a catalyst as described in document FR3117381, it would be advantageous to extract the metals of interest, particularly a Group VIII metal and / or a Group VIB metal, while avoiding the extraction of contaminants, especially arsenic, to prevent "polluting" the future impregnation solution. The present invention thus aims at a selective extraction of Group VIII and / or Group VIB metals by related to contaminants, particularly arsenic. When extracting the target metals, the extraction of at least some of one or more contaminants is often unavoidable. Treating contaminated catalysts is not straightforward because contaminant extraction depends on their nature and concentration. Contaminants will not all distribute themselves equally between the solution and the leached catalyst, depending on their nature and the leaching agent used.

[0009] Document FR3117381 proposes removing arsenic by heat treatment under a gas stream containing hydrogen sulfide before extraction. The present invention notably presents an improvement to the process described in document FR3117381, making it possible to eliminate the heat treatment under a gas stream containing hydrogen sulfide for removing arsenic.

[0010] Furthermore, the choice of certain organic compounds, combined with a high concentration of these organic compounds in the extraction solution, allows us to observe a high extraction selectivity of the group VIB metal and the group VIII metal compared to arsenic, which remains largely in the leached catalyst. Summary of the invention

[0011] The invention relates to a process for producing a catalyst comprising at least one metal from group VIB, and / or at least one metal from group VIII, optionally phosphorus and / or sulfur, and an oxide-based support, characterized in that said process comprises recycling at least a portion of the metal(s) from group VIB and / or group VIII from a source catalyst comprising at least one metal from group VIB and / or at least one metal from group VIII common to the catalyst to be produced, said source catalyst being contaminated, the process comprising:

[0012] - an extraction of the metal from group VIB and / or the metal from group VIII said catalyst source by an extraction solution comprising at least one organic compound having complexing properties, to obtain a solution of extracted metal(s), then

[0013] - impregnation of the support with an impregnation solution from said solution of extracted metal(s), to obtain an impregnated substrate, said extracted metal(s) remaining in liquid phase from extraction until impregnation.

[0014] The process according to the invention makes it possible to ensure a high rate of extraction of group VIII and / or VIB metals while limiting the extraction of contaminants, and in particular arsenic.

[0015] Furthermore, the invention proposes a process in which the metal from the source catalyst is dissolved and remains in solution until its reuse as a top-up of the impregnation solution to produce the fresh / new catalyst. Unlike the Unlike prior techniques, the invention does not seek to recover the source catalyst metal in solid, monometallic form, thus avoiding numerous precipitation / filtration operations. The process of the invention is therefore easier to implement on an industrial scale. It is further simplified when the extraction solution and the impregnation solution share a solvent (or mixture of solvents), particularly when the solvents of both solutions are identical (or similar, differing only in the proportion of solvents, for example, in the case of a mixture of solvents).

[0016] According to one variant, the source catalyst is contaminated with nickel and / or vanadium and / or iron and / or titanium and / or silicon and / or calcium and / or sodium and / or potassium and / or chlorine and / or arsenic.

[0017] According to one embodiment, the organic compound is selected from at least one of the following compounds: dimethylglyoxime, methyl acetoacetate, ethyl acetoacetate, ethyl lactate, methyl glycolate, ethyl glycolate, dimethyl malate, diethyl malate, dimethyl tartrate, diethyl tartrate, ethyl 3-hydroxybutanoate, ethyl 3-ethoxypropanoate, methyl 3-methoxypropanoate, methyl 3-(methylthio)propanoate, ethyl 3-(methylthio)propanoate, ethylene glycol, diethylene glycol, triethylene glycol, a polyethylene glycol (with a molecular weight between 200 and 1500 g / mol), propylene glycol, glycerol, the 2-Butoxyethanol, 2-(2-butoxyethoxy)ethanoyl, 2-(2-methoxyethoxy)ethanol, triethylene glycol dimethyl ether, a crown ether, acetophenone, 2,4-pentanedione, pentanone, glucose, fructose, sucrose, sorbitol, xylitol, mannitol, γ-valerolactone,Propylene carbonate, octylamine, N,N-diethylformamide, N,N-dimethylformamide, N-methylformamide, N,N-dimethylacetamide, propanamide, l-methyl-2-pyrrolidinone, tetramethylurea, N,N'-dimethylurea, acetonitrile, lactamide, furfurol, 2-furaldehyde, 5-hydroxymethylfurfural, ethyl 3-hydroxybutanoate, 2-hydroxyethyl acrylate, l-vinyl-2-pyrrolidinone, N,N,N',N'-tetramethyltartramide, 3-hydroxypropionitrile, and N,N'-bis(2-hydroxyethyl)ethylenediamine.

[0018] According to one variant, the extraction solution comprises at least one organic compound having complexing and also acidic properties.

[0019] According to one embodiment, the organic compound is chosen from at least one of the following compounds: formic acid, acetic acid, oxalic acid, malonic acid, glutaric acid, glycolic acid, lactic acid, tartronic acid, citric acid, tartaric acid, pyruvic acid, γ-ketovaleric acid, succinic acid, acetoacetic acid, gluconic acid, ascorbic acid, phthalic acid, salicylic acid, maleic acid, malic acid, fumaric acid, acrylic acid, thioglycolic acid, 2-hydroxy-4-methylthiobutanoic acid, glutamic acid, N-acetylglutamic acid, alanine, glycine, cysteine, histidine, aspartic acid, N-acetylaspartic acid, 4-aminobutanoic acid, 1,2-cyclohexanediaminetetraacetic acid, ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), iminodiacetic acid (IDA), N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), bicine, tricine, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP or etidronic acid), nitrilotris(methylenephosphonic) acid, diethylenetriaminepentakis(methylenephosphonic) acid, 4-Sulfophthalic acid, 3-(N-morpholino)-2-hydroxy-l-propanesulfonic acid (MOPSO), 2-(4-Pyridinyl)ethanesulfonic acid, phenol-4-sulfonic acid, thiodiacetic acid and diglycolic acid.

[0020] According to one variant, the organic compound is chosen from formic acid, acetic acid, oxalic acid, citric acid, γ-ketovaleric acid, fructose, ethylene glycol, diethylene glycol and triethylene glycol.

[0021] According to one variant, the source catalyst is a used catalyst that has been previously regenerated and / or rejuvenated.

[0022] According to one variant, the extraction solution comprises a mineral acid selected from phosphoric acid, nitric acid or boric acid.

[0023] According to one variant, the concentration of each organic compound in the extraction solution is between 0.03 and 2 mol / L.

[0024] According to one variant, the source catalyst is subjected to at least one pretreatment step before the extraction step chosen from among oil removal, regeneration, grinding or water washing.

[0025] According to one variant, the extracted metal / metal(s) solution is subjected to at least one treatment step before impregnation of the support, said treatment step being chosen from a concentration, a dilution and / or a modification of the composition of the solution by addition or removal, total or partial, of at least one compound of said solution.

[0026] According to one variant, the impregnation of the support with an impregnation solution is carried out from the solution of extracted metal(s) and a supplement of at least one of the metals of group VIII / VIB, and possibly of phosphorus and / or of organic additive(s).

[0027] According to one variant, at least part of the impregnation solution is reused after the support has been impregnated as a supplement to the extraction solution.

[0028] According to one embodiment, the substrate on which the impregnation is carried out with the impregnation solution derived from the extracted metal(s) solution is pre-impregnated or post-impregnated with an impregnation solution or is a metal-depleted catalyst.

[0029] According to one variant, said impregnated substrate obtained after impregnation is subjected to a drying step, optionally to a calcination step and optionally to a sulfidation step.

[0030] According to one variant, the source catalyst is contaminated with arsenic and the extraction rate of the metal from group VIII or group VIB is respectively greater than 50% by weight and the extraction rate of arsenic is less than 30% by weight, the extraction rate corresponding to the mass of the metal(s) extracted and the arsenic extracted in the extraction solution relative to the mass of the metal(s) present and the arsenic initially present on the source catalyst. Definitions

[0031] In the sense of the present invention, the different embodiments presented can be used alone or in combination with each other, without limitation of combination.

[0032] In the sense of the present invention, the different parameter ranges for a given step, such as pressure ranges and temperature ranges, can be used alone or in combination. For example, in the sense of the present invention, a preferred range of pressure values ​​can be combined with a preferred range of temperature values.

[0033] In the following text, the expressions "between ... and ..." and "between ... and ..." are equivalent and mean that the limit values ​​of the interval are included in the range of values ​​described. If this were not the case and the limit values ​​were not included in the range described, such clarification will be provided by the present invention.

[0034] In this description, the term "include" is synonymous with (means the same as) "include" and "contain," and is inclusive or open and does not exclude other elements not mentioned. It is understood that the term "include" includes the exclusive and closed term "consist."

[0035] According to the present invention, it is understood that the impregnation solution is "derived" from the extraction solution as meaning that there is no intermediate treatment where the extracted metal(s) would be in solid phase, nor any liquid / liquid extraction treatment of the latter.

[0036] In this description, the term "extraction" is synonymous with the term "leaching," unless otherwise indicated. The terms "leaching" or "extraction" in this description refer to the process of extracting one or more metals from a solid (source catalyst) by dissolving it in a liquid (leaching solution or extraction solution).

[0037] In this description, the term "metal / metals extracted" refers to the target metals, i.e., metals of group VIII and / or VIB. Other metals are considered contaminants.

[0038] In this description, the term “contaminants” refers to undesirable elements in the source catalyst and in the extraction solution that are not to be extracted. Contaminants include, in particular, nickel and / or vanadium and / or iron and / or titanium and / or silicon and / or calcium and / or sodium and / or potassium and / or chlorine and / or arsenic.

[0039] For the purposes of the present invention, a distinction must be made between the nickel potentially contained in the active phase of the source catalyst (and which is to be extracted) and the contaminating nickel introduced by the feedstock. Unlike the nickel in the active phase, which is homogeneously distributed throughout the catalyst, the contaminating nickel is generally more concentrated at the periphery of the catalyst grain (beads, extrudates, etc.), and forms more or less evenly distributed clusters. Its presence as decoration on the MoS2 is also very limited.

[0040] According to the present invention, the pressures are absolute pressures, also noted abs., and are given in absolute MPa (or abs. MPa), unless otherwise indicated.

[0041] In the following text, the groups of chemical elements are given according to the CAS classification (CRC Handbook of Chemistry and Physics, publisher CRC Press, editor-in-chief DR Lide, 81st edition, 2000-2001). For example, group VIII (or VIIIB) according to the CAS classification corresponds to the metals in columns 8, 9 and 10 according to the new IUP AC classification, and group VIB to the metals in column 6.

[0042] Elemental analyses, typically by inductively coupled plasma (ICP) spectrometry, or by X-ray fluorescence spectrometry, more commonly called X-ray fluorescence (FX), make it possible to quantify the content of the different elements of the catalyst pretreated at 550°C under air and of the extraction solution. Detailed description

[0043] The present invention relates to the recycling of metals from catalysts originating in particular from hydrotreating or hydroconversion units of hydrocarbons.

[0044] Hydrotreating refers to all purification processes that remove various impurities contained in hydrocarbon feedstocks through the action of hydrogen. Hydrotreating processes remove impurities present in feedstocks such as nitrogen (hydrodeazotation), sulfur (hydrodesulfurization), oxygen (hydrodeoxygenation), and compounds containing metals that can poison the catalyst and cause downstream operational problems (hydrodemetallation). Hydrotreating This process allows hydrocarbons to be brought to the required specifications (sulfur content, aromatics, etc.) for a given application (automotive fuel, gasoline or diesel, heating oil, etc.). Automotive standards, in particular, have mandated a significant reduction in sulfur in diesel and gasoline fuels, and hydrotreating makes it possible to bring these products to the required specifications.

[0045] Hydrotreating will therefore improve the quality of hydrocarbons by reducing The content of certain compounds, elements considered impurities, can be reduced, but it can also be used to decrease the content of aromatic hydrocarbons through hydrogenation, thus improving the cetane number of hydrocarbons. During hydrotreating processes, small quantities of fuel gas and light fractions such as LPG (Liquefied Petroleum Gas) and naphtha can also be produced.

[0046] It should be noted that hydrocracking (also known as hydroconversion) of heavy hydrocarbon fractions is a key refining process that allows the production, from excess and low-value heavy feedstocks, of lighter fractions such as gasoline, jet fuel, and light diesel fuels that refiners seek to adapt their production to demand. Some hydrocracking processes also make it possible to obtain a highly purified residue that can constitute excellent base oils.

[0047] The hydrocarbon feedstock targeted by hydrotreatment and / or hydroconversion can be of different types. In particular, the feedstock may be of fossil origin or derived from the conversion of biomass or waste, either alone or in mixtures. The feedstocks that are treated, and in particular those mentioned below, generally contain heteroatoms such as sulfur, oxygen, and nitrogen, and may contain other contaminants such as iron, titanium, silicon, calcium, sodium, potassium, chlorine, and arsenic, but also, especially for heavier feedstocks, nickel and vanadium.

[0048] The fossil fuel feedstock may include, in particular, a fraction derived from coal or hydrocarbons produced from natural gas, possibly in mixtures. It may also consist of heavy petroleum or synthetic fractions, for example, kerosene, gas oil, or distillates obtained by atmospheric and vacuum distillation to produce usable kerosene, gas oil, or vacuum distillate, either in the storage unit receiving products of the same type (a "pool") or to a downstream unit such as a catalytic cracking unit, where the feedstocks are "cracked" to produce shorter-chain hydrocarbons. It is common for the hydrotreating process to be, in fact, a preliminary step in the treatment of a feedstock by a hydroconversion / hydrocracking process.

[0049] The feedstocks of fossil origin used in a hydrotreating process, in more detail, have for example gasolines, gas oils, vacuum gas oils, atmospheric residues, vacuum residues, atmospheric distillates, vacuum distillates, heavy fuels, oils, waxes and paraffins, used oils, residues or deasphalted crudes, feedstocks from thermal or catalytic conversion processes, taken alone or in mixture.

[0050] The feedstock resulting from biomass conversion may advantageously be selected from vegetable oils, algae or algal oils, fish oils, used cooking oils, and fats of vegetable or animal origin; or mixtures of such feedstocks. Said vegetable oils may advantageously be crude or refined, wholly or partially, and derived from plants selected from rapeseed, sunflower, soybean, palm, olive, coconut, copra, castor, cottonseed, peanut, linseed, and crambe oils, and all oils derived, for example, from sunflower or rapeseed by genetic modification or hybridization, this list not being exhaustive. Said animal fats are advantageously selected from lard and fats composed of residues from the food industry or from the catering industry.Frying oils, various animal oils such as fish oil, tallow, and lard can also be used. The feedstock from biomass conversion can also advantageously be chosen from among methyl esters of fatty acids of vegetable and / or animal origin, or from methyl esters of fatty acids from used edible vegetable oils.

[0051] The feedstock resulting from biomass conversion can also be selected from feedstocks obtained from thermal or catalytic biomass conversion processes, such as oils produced from biomass, particularly lignocellulosic biomass, using various liquefaction methods, such as hydrothermal liquefaction or pyrolysis. The term "biomass" refers to material derived from recently living organisms, including plants, animals, and their by-products. The term "lignocellulosic biomass" refers to biomass derived from plants or their by-products. Lignocellulosic biomass is composed of carbohydrate polymers (cellulose, hemicellulose) and an aromatic polymer (lignin).

[0052] The feed from biomass conversion can also advantageously be chosen from feeds from the paper industry.

[0053] The feedstock from waste conversion can be a pyrolysis oil derived from plastics, tires, or solid recovered fuels (SRF). These oils are obtained by thermal pyrolysis, catalytic pyrolysis, or hydropyrolysis (pyrolysis in the presence of a catalyst and hydrogen).

[0054] Conventional hydrotreating catalysts generally comprise an oxide support and an active phase based on metals from groups VIB and VIII in their oxide forms, as well as phosphorus. The preparation of these catalysts generally includes a step of impregnating the support with the metals and phosphorus, followed by drying and calcination to obtain the active phase in its oxide forms. Before their use in a hydrotreating and / or hydroconversion reaction, these catalysts are also generally subjected to sulfidation.

[0055] The addition of an organic additive to hydrotreating catalysts to improve their activity is also known, particularly for catalysts that have been prepared by impregnation followed by drying without subsequent calcination. These catalysts are often called "additized dried catalysts".

[0056] The catalysts used in hydrocracking are bifunctional, that is, they combine an acidic function with a hydrogenating function. The acidic function is provided by supports with large surface areas (generally 150 to 800 m².g⁻¹) exhibiting significant acidity, such as halogenated aluminas (particularly chlorinated or fluorinated), combinations of boron and aluminum oxides, amorphous silica-aluminas, and zeolites. The hydrogenating function is provided either by one or more metals from Group VIII, or by a combination of at least one metal from Group VIB and at least one metal from Group VIII, implemented in the presence of sulfur. The equilibrium between the two acidic and hydrogenating functions governs the activity and selectivity of the catalyst.

[0057] During its operation in a hydrotreating or hydroconversion process, the catalyst becomes deactivated by the accumulation on its surface of coke and / or sulfur compounds and / or other contaminants such as nickel, vanadium, iron, titanium, but also silicon, calcium, sodium, potassium, chlorine and arsenic. After a certain period, its replacement is therefore necessary.

[0058] To combat these drawbacks, the regeneration (also called soft calcination) of hydrotreating / hydroconversion catalysts is an economically and environmentally advantageous process, as it allows these catalysts to be reused in industrial units rather than being sent to landfills or recycled (metal recovery). Regeneration consists of a thermal treatment, generally between 350°C and 550°C, in the presence of pure or diluted oxygen, aimed at removing at least some of the coke present on the spent catalyst through combustion. This regeneration allows the so-called "regenerated" catalyst to regain hydrotreating / hydroconversion activity. However, regenerated catalysts are generally less active than the initial, or "fresh," catalysts. Consequently, their cycle time in the hydrotreating / hydroconversion unit is This reduces the energy consumption compared to that of a fresh catalyst. It can potentially be reused in less demanding applications.

[0059] To compensate for the reduced hydrotreating / hydroconversion activity of the regenerated catalyst, an additional treatment known as "rejuvenation" can be applied. The rejuvenation process consists of re-impregnating the already regenerated catalyst with a solution containing organic or inorganic additives and / or metallic precursors. These rejuvenation processes are well known, particularly in the field of middle distillates. Although more efficient than simple regeneration, catalyst rejuvenation generally results in a catalyst with lower activity than the fresh catalyst.Finally, some spent catalysts cannot be reused via regeneration or rejuvenation, either because their integrity is compromised (size or mechanical resistance too low), or because they contain too many contaminants, rendering the performance of the regenerated or rejuvenated product insufficient.

[0060] Although the present invention relates to the recycling of catalyst metals, particularly those from hydrocarbon hydrotreating or hydroconversion units, it is understood that the process according to the invention applies to any catalyst comprising at least one metal from Group VIII and / or at least one metal from Group VIB, and an oxide support, such as, for example, selective hydrogenation catalysts, hydrotreating catalysts for residues (for example, carried out in a boiling bed), or Fischer-Tropsch catalysts. The source catalyst

[0061] According to the present invention, the term "source catalyst" refers to the catalyst from which metals are to be extracted. The "source catalyst" is generally a catalyst that is at least partially used, that is, one that has already been used in production, particularly in hydrotreating or hydroconversion plants, for example, hydrocracking plants. This catalyst may have already been regenerated and / or rejuvenated prior to its recycling. The term also includes a catalyst that has not already been used in production but is out of specification, for example, because it contains an insufficient metal content or has too low a mechanical strength, or is smaller than the required size resulting from the various unit operations in the manufacture of new catalysts (for example, "fines" of catalyst particles). The term also includes a collection mass that is at least partially used.

[0062] The source catalyst comprises at least one metal from Group VIII and / or at least one metal from Group VIB, an oxide support, and optionally phosphorus. The source catalyst is contaminated. It may be contaminated with nickel and / or vanadium and / or iron and / or titanium and / or silicon and / or calcium and / or sodium and / or to potassium and / or chlorine and / or arsenic. Preferably, it includes at least arsenic as a contaminant. It may also, but is not limited to, include coke and / or sulfur.

[0063] The oxide support of said catalyst source is usually a porous solid selected from the group consisting of: aluminas, silica, silica-aluminas, or titanium or magnesium oxides used alone or in a mixture with alumina or silica-alumina. Preferably, the oxide support is essentially composed of at least one transition alumina, that is to say, it comprises at least 51 wt%, preferably at least 60 wt%, most preferably at least 80 wt%, or even at least 90 wt% of transition alumina. It is preferably composed solely of one transition alumina. Preferably, the oxide support of said catalyst is a gamma-phase alumina.

[0064] In another preferred case, the oxide present in the support of said source catalyst is a silica-alumina containing at least 50% by weight of alumina relative to the total weight of the composite support. The silica content in the support is at most 50% by weight relative to the total weight of the support, most often less than or equal to 45% by weight, preferably less than or equal to 40% by weight.

[0065] According to a particularly preferred embodiment, the support of the source catalyst is made of alumina, silica or silica-alumina.

[0066] The oxide support may also advantageously contain from 0.1 to 80 wt%, preferably from 0.1 to 50 wt%, of zeolite relative to the total weight of the support. In this case, all known sources of zeolite and all associated preparation methods may be incorporated. Preferably, the zeolite is selected from the FAU, BEA, ISV, IWR, IWW, MEI, and UWY groups, and more preferably, the zeolite is selected from the FAU and BEA groups, such as Y and / or beta zeolite, and particularly preferably, such as USY and / or beta zeolite.

[0067] The support is advantageously in the form of irregular and non-spherical beads, extrudates, pellets or agglomerates whose specific shape may result from a crushing step.

[0068] The oxide support advantageously has a total pore volume of between 0.1 and 1.5 mL / g, preferably between 0.4 and 1.1 mL / g. The total pore volume is measured by mercury porosimetry according to ASTM D4284-92 with a wetting angle of 140°, for example using a Microméritics™ Autopore III™ instrument.

[0069] The specific surface area of ​​the oxide support is advantageously between 5 and 400 m².g*, preferably between 10 and 350 m².g*, more preferably between 40 and 350 m2.g'. The specific surface area is determined in the present invention by the BET method according to ASTM D3663.

[0070] The active phase of the source catalyst comprises at least one metal from Group VIB and / or at least one metal from Group VIII. The Group VIB metal present in the active phase of the catalyst is preferably chosen from molybdenum and tungsten, or a mixture of these two elements. The Group VIII metal present in the active phase of the catalyst is preferably chosen from cobalt, nickel, and a mixture of these two elements. The active phase of the catalyst is preferably chosen from the group formed by the combination of nickel-molybdenum, cobalt-molybdenum, nickel-cobalt-molybdenum, nickel-tungsten, nickel-molybdenum-tungsten, and nickel-cobalt-tungsten.

[0071] The Group VIII metal content is between 1 and 50% by weight of Group VIII metal oxide relative to the total weight of the source catalyst, preferably between 1 and 10% by weight, preferably between 1.5 and 9% by weight, and preferably between 2 and 8% by weight. When the metal is cobalt or nickel, the metal content is expressed as CoO and NiO, respectively.

[0072] The metal content of group VIB is between 5 and 40 wt% of the oxide of the group VIB metal relative to the total weight of the source catalyst, preferably between 8 and 35 wt%, most preferably between 10 and 30 wt%. When the metal is molybdenum or tungsten, the metal content is expressed as MoO3 and WO3 respectively.

[0073] The molar ratio of group VIII metal to group VIB metal in the catalyst, when the latter contains both types of metals, is preferably between 0.1 and 0.8, preferably between 0.15 and 0.6 and even more preferably between 0.2 and 0.6 or between 0.3 and 0.5.

[0074] The source catalyst may also include phosphorus as a dopant. The dopant is an added element which, in itself, has no catalytic character but which increases the catalytic activity of the active phase.

[0075] The phosphorus content in said source catalyst is then preferably between 0.1 and 20% by weight expressed as P2O5 relative to the total weight of the source catalyst, preferably between 0.2 and 15% by weight expressed as P2O5, and most preferably between 0.3 and 8% by weight expressed as P2O5.

[0076] The phosphorus molar ratio to the element of group VIB in the catalyst is greater than or equal to 0.05, preferably greater than or equal to 0.07, preferably between 0.08 and 1, preferably between 0.01 and 0.9 and most preferably between 0.15 and 0.6.

[0077] The source catalyst may contain sulfur. The sulfur content in said source catalyst is then preferably between 1 and 15% by weight expressed as an element relative to the total weight of the source catalyst, preferably between 2 and 12%, and most preferably between 4 and 10% by weight. The sulfur content is measured by elemental analysis according to ASTM D5373.

[0078] The source catalyst may include coke, particularly when it has not been regenerated. It should be noted that the term "coke" in this application refers to a hydrocarbon-based substance deposited on the surface of the catalyst during its use, which is highly cyclized and condensed and has an appearance similar to graphite.

[0079] The coke content, expressed as a percentage by weight of the carbon element, may be between 2 and 20% by weight, preferably between 3 and 16% by weight, and in particular between 4 and 14% by weight relative to the total weight of the source catalyst. The coke content is determined according to ASTM D5373.

[0080] The source catalyst is contaminated with at least one contaminant selected from nickel, vanadium, iron, titanium, silicon, calcium, sodium, potassium, chlorine and arsenic. Preferably, it includes at least arsenic as a contaminant.

[0081] The arsenic content of the source catalyst is generally less than or equal to 25,000 ppm by weight relative to the total weight of the source catalyst. Preferably, it is between 0 and 25,000 ppm by weight, preferably between 1,500 and 25,000 ppm by weight, and preferably between 2,500 and 20,000 ppm by weight relative to the total weight of the source catalyst.

[0082] The nickel (contaminant) content of the source catalyst (other than that possibly present as an active phase on the fresh catalyst) is generally less than or equal to 30,000 ppm by weight relative to the total weight of the source catalyst. Preferably, it is between 0 and 30,000 ppm by weight, preferably between 1,000 and 30,000 ppm by weight, and preferably between 4,000 and 10,000 ppm by weight relative to the total weight of the source catalyst.

[0083] The vanadium content of the source catalyst is generally less than or equal to 50,000 ppm by weight relative to the total weight of the source catalyst. Preferably, it is between 0 and 50,000 ppm by weight, preferably between 1,000 and 50,000 ppm by weight, and preferably between 4,000 and 30,000 ppm by weight relative to the total weight of the source catalyst.

[0084] The iron content of the source catalyst is generally less than or equal to 50,000 ppm by weight relative to the total weight of the source catalyst. Preferably, it is between 0 and 50,000 ppm by weight, preferably between 1,500 and 50,000 ppm by weight, and most preferably between 2,000 and 10,000 ppm by weight relative to the total weight of the source catalyst.

[0085] The titanium content of the source catalyst is generally less than or equal to 5000 ppm by weight relative to the total weight of the source catalyst. Preferably, it is between 0 and 5000 ppm by weight, preferably between 100 and 5000 ppm by weight, and most preferably between 200 and 2000 ppm by weight relative to the total weight of the source catalyst.

[0086] The silicon content of the source catalyst (in addition to any silicon present on the fresh catalyst) is generally less than or equal to 100,000 ppm by weight relative to the total weight of the source catalyst. Preferably, it is between 0 and 100,000 ppm by weight, more preferably between 1,000 and 100,000 ppm by weight, and most preferably between 2,000 and 50,000 ppm by weight relative to the total weight of the source catalyst.

[0087] The calcium content of the source catalyst is generally less than or equal to 10,000 ppm by weight relative to the total weight of the source catalyst. Preferably, it is between 0 and 10,000 ppm by weight, preferably between 100 and 10,000 ppm by weight, and preferably between 500 and 5,000 ppm by weight relative to the total weight of the source catalyst.

[0088] The sodium content of the source catalyst (in addition to any sodium present on the fresh catalyst) is generally less than or equal to 10,000 ppm by weight relative to the total weight of the source catalyst. Preferably, it is between 0 and 10,000 ppm by weight, preferably between 100 and 10,000 ppm by weight, and preferably between 500 and 5,000 ppm by weight relative to the total weight of the source catalyst.

[0089] The potassium content of the source catalyst is generally less than or equal to 20,000 ppm by weight relative to the total weight of the source catalyst. Preferably, it is between 0 and 20,000 ppm by weight, preferably between 100 and 20,000 ppm by weight, and preferably between 500 and 10,000 ppm by weight relative to the total weight of the source catalyst.

[0090] The chlorine content of the source catalyst is generally less than or equal to 5000 ppm by weight relative to the total weight of the source catalyst. Preferably, it is between 0 and 5000 ppm by weight, preferably between 100 and 5000 ppm by weight, and most preferably between 200 and 2000 ppm by weight relative to the total weight of the source catalyst.

[0091] The source catalyst obtained from a hydrotreating process of a medium distillate feed (diesel, kerosene) or a naphtha feed is distinguished by lower vanadium and nickel contents (other than the active phase) than that of a catalyst obtained from a hydroconversion process of a heavier feed. The vanadium and nickel contents of a source catalyst obtained from a hydrotreating process of a medium distillate feed (diesel, kerosene) or a naphtha feed are generally less than or equal to 10,000 ppm wt for nickel (other than the active phase). and less than or equal to 50000 ppm by weight for vanadium relative to the weight of the source catalyst. Pretreatments (optional)

[0092] The source catalyst may be subjected to at least one pretreatment step prior to extraction according to the process of the invention. The optional pretreatment step consists of removing all or part of one or more of the impurities that may be contained in said source catalyst before the metal extraction step, by any method known to those skilled in the art. The pretreatment step may be chosen from oil removal, regeneration, grinding, or even washing with water. These preliminary treatments aim to make the extraction more efficient through mechanical, physical, or chemical processes: grinding reduces the particle size of the source catalyst particles and increases the contact surface area between the particles and the extraction solution.Removing or reducing the amount of coke and other contaminants has the same effect, improving / increasing the contact between the extraction solution and the metals to be extracted contained in the source catalyst. Preferably, the pretreatment step includes a regeneration step to remove all or part of the coke, sulfur and / or chlorine, as detailed below. • Degreasing

[0093] The discharge of the source catalyst from a hydrotreating and / or hydroconversion process is preferably preceded by a de-oiling step. The de-oiling step generally comprises contacting the source catalyst with a stream of inert gas (i.e., essentially oxygen-free), for example in a nitrogen or similar atmosphere, at a temperature between 300°C and 400°C, preferably between 300°C and 350°C. The inert gas flow rate, expressed as a flow rate per unit volume of the catalyst, is 5 to 150 NL.h⁻¹ for 3 to 7 hours. Alternatively, the de-oiling step can be carried out using light hydrocarbons, by steam treatment, or any other similar process.

[0094] The oil removal step is generally followed by a drying step and / or a heating step, preferably at a temperature between 50°C and 200°C. The drying gas is preferably an inert gas such as nitrogen. • Regeneration

[0095] The source catalyst, possibly de-oiled, can be subjected to a coke and sulfur removal step: a regeneration step, which makes it possible to remove all or part of the coke, sulfur and / or chlorine possibly deposited on the catalyst.

[0096] Although possible, regeneration is preferably not carried out by keeping the loaded catalyst in the hydrotreating reactor (in-situ regeneration). Preferably, the source catalyst is therefore extracted from the reactor and sent to a regeneration facility to perform regeneration in said facility (ex-situ regeneration).

[0097] The regeneration step is generally carried out in a gas stream containing oxygen, usually air. The water content in the gas is generally between 0 and 50 wt%. The gas flow rate, in terms of flow rate per unit volume of the source catalyst, is preferably 20 to 2000 NL.h⁻¹, more preferably 30 to 1000 NL.h⁻¹, and particularly preferably 40 to 500 NL.h⁻¹. The regeneration time is preferably 2 hours or more, more preferably 2.5 hours or more, and particularly preferably 3 hours or more. The regeneration of the source catalyst is generally carried out at a temperature between 320°C and 550°C, preferably between 360 and 500°C.

[0098] The regenerated catalyst consists of the oxide support and the active phase formed of at least one metal from Group VIB and / or at least one metal from Group VIII and optionally phosphorus from the source catalyst. The regenerated catalyst contains substantially the same content of Group VIB and / or VIII metal as the source catalyst. The regenerated catalyst contains substantially the same content of contaminants, with the exception of coke, sulfur, and chlorine.

[0099] The regenerated catalyst is characterized by a specific surface area of ​​between 20 and 300 m2 / g, preferably between 30 and 280 m2 / g, preferably between 40 and 260 m2 / g, most preferably between 80 and 250 m2 / g.

[0100] The porous volume of the regenerated catalyst is generally between 0.1 cm3 / g and 1.3 cm3 / g, preferably between 0.2 cm3 / g and 1.1 cm3 / g.

[0101] The regenerated catalyst obtained in the regeneration step contains residual carbon at a level of less than 3% by weight relative to the total weight of the regenerated catalyst, preferably between 0% and 2.9% by weight relative to the total weight of the regenerated catalyst, preferably between 0% and 2.0% by weight, and particularly preferably between 0% and 1.0% by weight. It should be noted that the term "residual carbon" in this application means carbon (coke) remaining in the regenerated catalyst after regeneration of the source catalyst. This residual carbon content in the regenerated catalyst is measured according to ASTM D5373. The sulfur content after regeneration is preferably between 0 and 4% by weight expressed as an element relative to the weight of the catalyst, preferably between 0 and 2% by weight. The chlorine content after regeneration is preferably between 0 and 0.2% by weight. % weight expressed as an element relative to the weight of the catalyst, preferably between 0 and 0.1% weight. • Crushing

[0102] The source catalyst, optionally de-oiled and / or regenerated, may advantageously undergo an optional grinding step before extraction to enhance the metal extraction kinetics in the process according to the invention. In this case, the step includes an optional first conditioning phase of the source catalyst with at least one grinding step to obtain catalyst particles with a size of no more than 1 mm. It is, of course, possible to carry out several successive grinding steps to achieve the desired particle size. Any method known to those skilled in the art can be used to perform this crushing or grinding step, such as, for example, the use of a ball mill or a blade mill.Preferably, 90% of the volume distribution of the source catalyst particles has an equivalent diameter between 1 and 1000 micrometers, preferably between 5 and 500 micrometers, preferably between 10 and 300 micrometers, and particularly preferably between 15 and 150 micrometers. The equivalent diameter, denoted "de", is defined according to the following relationship: de = 6V / S, where V is the volume of the particle and S is the surface area of ​​the sphere with the same volume as the particle.

[0103] Most often, the crushed source catalyst is brought into the extraction zone by any means known to those skilled in the art, in particular by a transfer screw or by pneumatic transfer. • Wash with water

[0104] The source catalyst, possibly de-oiled and / or regenerated and / or ground, may undergo a water washing step.

[0105] The volume of water used in this washing step is advantageously greater than the total pore volume of the source catalyst. This volume may, in particular, be within a range of 2 to 20 times the total pore volume of the source catalyst, preferably between 5 and 10 times said pore volume.

[0106] The washing step can be carried out at any suitable temperature, for example between 5°C and 150°C, preferably between ambient temperature (20°C) and 70°C.

[0107] During the washing step, it is advantageous to stir the source catalyst to ensure effective washing. The washing step can be carried out continuously or batchwise, with batch mode being preferred as it limits the amount of water used. The washing step can be carried out in any type of solid / liquid extractor or industrial mixer. Extraction stage

[0108] According to the process according to the invention, an extraction of the metal from group VIB and / or the metal from group VIII of said source catalyst, possibly pre-treated, is carried out by an extraction solution comprising at least one organic compound having complexing properties to obtain a solution of extracted metal(s).

[0109] The extraction solution according to the present invention may comprise any polar protic solvent known to those skilled in the art. Preferably, a polar protic solvent is used, for example, one chosen from the group consisting of methanol, ethanol, and water, or a water-ethanol or water-methanol mixture. Most preferably, the solvent used in the impregnation solution is water. In the case of an aqueous solution, the pH of said solution may be modified by the optional addition of an acid or a base. The extraction solution generally has a pH between 0.1 and 8.5, preferably between 0.5 and 6, and preferably between 1 and 4.

[0110] Preferably, the extraction solution and the impregnation solution of the next step have at least one solvent in common. They may have the same solvent or mixture of solvents, or, in the case of a mixture, a mixture of solvents that vary in proportion. For example, it may be water, or a mixture of solvents comprising predominantly, or essentially, an aqueous solvent.

[0111] Preferably, the extraction of metals is carried out with a solution comprising a solvent, in particular aqueous, and at least one organic compound having complexing properties, and possibly also acidic (either at least one compound having both properties, or the combination of at least one acidic compound and at least one complexing compound, or only at least one complexing compound for example).

[0112] It has indeed been shown that adding an organic compound to the solution (generally aqueous) was very effective in extracting the metals of interest that one wants to recycle, by making them pass into the liquid phase, while the support of the source catalyst and any other components, including arsenic, of the source catalyst remain largely in the solid phase and are thus easily eliminated.

[0113] It should be noted that the organic compounds that give the most interesting results are often compounds with acidic and complexing properties. Indeed, an organic acid allows the metal oxide to be protonated, thus limiting its interaction with the support and promoting its dissolution in the extraction solution. A complexing agent, on the other hand, allows the formation of a metal complex soluble in the extraction solution. The combination of acidic and complexing properties is therefore particularly advantageous: the use of an organic compound having these two properties, or the combination of an acidic organic compound and a complexing organic compound, is thus particularly recommended.

[0114] This organic compound, or at least one of them when there are several, may comprise one or more chemical functions selected from a carboxylic acid, phosphoric acid, sulfonic acid, alcohol, thiol, thioether, sulfone, sulfoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile, imide, oxime, urea and amide function, or compounds including a furanic ring or sugars.

[0115] The organic compound (or at least one of them when there are several) exhibiting both acidic and complexing properties may be selected from at least one of the following compounds: formic acid, acetic acid, oxalic acid, malonic acid, glutaric acid, glycolic acid, lactic acid, tartronic acid, citric acid, tartaric acid, pyruvic acid, γ-ketovaleric acid, succinic acid, acetoacetic acid, gluconic acid, ascorbic acid, phthalic acid, salicylic acid, maleic acid, malic acid, fumaric acid, acrylic acid, thioglycolic acid, 2-hydroxy-4-methylthiobutanoic acid, glutamic acid, N-acetylglutamic acid, alanine, glycine, cysteine, histidine, aspartic acid, N-acetylaspartic acid, 4-aminobutanoic acid, 1,2-cyclohexanediaminetetraacetic acid, ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA),iminodiacetic acid (IDA), N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), bicine, tricine, l-hydroxyethylidene-l,l-diphosphonic acid (HEDP or etidronic acid), nitrilotris(methylenephosphonic) acid, diethylenetriaminepentakis(methylenephosphonic) acid, 4-Sulfophthalic acid, 3-(N-morpholino)-2-hydroxy-l-propanesulfonic acid (MOPSO), 2-(4-Pyridinyl)ethanesulfonic acid, phenol-4-sulfonic acid, thiodiacetic acid and diglycolic acid.

[0116] The organic compound (or at least one of them when there are several) exhibiting complexing properties may be selected from at least one of the following compounds: dimethylglyoxime, methyl acetoacetate, ethyl acetoacetate, ethyl lactate, methyl glycolate, ethyl glycolate, dimethyl malate, diethyl malate, dimethyl tartrate, diethyl tartrate, ethyl 3-hydroxybutanoate, ethyl 3-ethoxypropanoate, methyl 3-methoxypropanoate, methyl 3-(methylthio)propanoate, ethyl 3-(methylthio)propanoate, ethylene glycol, diethylene glycol, triethylene glycol, a polyethylene glycol (with a molecular weight between 200 and 1500) g / mol), propylene glycol, glycerol, 2-butoxyethanol, 2-(2-butoxyethoxy)ethanoyl, 2-(2-methoxyethoxy)ethanol, triethylene glycol dimethyl ether, a crown ether, acetophenone, 2,4-pentanedione, pentanone, glucose, fructose, sucrose,sorbitol, xylitol, mannitol, γ-valerolactone, propylene carbonate, toctylamine, N,-diethylformamide, N,N-dimethylformamide, the , N-methylformamide, N,N-dimethylacetamide, propanamide, l-methyl-2-pyrrolidinone, tetramethylurea, N,N'-dimethylurea, acetonitrile, lactamide, furfurol, 2-furaldehyde, 5-hydroxymethylfurfural, ethyl 3-hydroxybutanoate, 2-hydroxyethyl acrylate, l-vinyl-2-pyrrolidinone, N,N,N',N'-tetramethyltartramide, 3-hydroxypropionitrile and N,N'-bis(2-hydroxyethyl)ethyl enediamine.

[0117] The concentration of each organic compound in the extraction solution is defined so that the molar ratio of organic compound to extracted metals is between 0.1 and 25, preferably between 0.2 and 11, preferably between 0.2 and 5, preferably between 0.3 and 3, and preferably between 0.4 and 2.

[0118] When several organic compounds are present, the different molar ratios apply to each of the organic compounds present.

[0119] The concentration of each organic compound in the extraction solution is generally between 0.03 and 2 mol / L, preferably between 0.1 and 1.3 mol / L, and particularly preferably between 0.5 and 1 mol / L.

[0120] The extraction solution comprising at least one organic compound having complexing and possibly acidic properties is chosen so as to maximize the extraction rate of the group VIII and / or VIB metal while limiting the extraction of contaminants, in particular arsenic.

[0121] The choice of certain organic compounds allows us to observe a strong selectivity of extraction of the group VIII metal and the group VIIB metal compared to arsenic, which remains largely in the leached catalyst.

[0122] According to a preferred embodiment, the organic compound is selected from a carboxylic acid that preferably comprises between 1 and 8 carbon atoms and that may be a mono-, di-, or tri-acid. Preferably, the organic compound is selected from acetic acid, glutaric acid, oxalic acid, glycolic acid, lactic acid, citric acid, γ-ketovaleric acid, acetoacetic acid, and gluconic acid.

[0123] According to another preferred variant, the organic compound is chosen from fructose, ethylene glycol, diethylene glycol and triethylene glycol.

[0124] According to a highly preferred embodiment, the organic compound is selected from formic acid, acetic acid, oxalic acid, citric acid, γ-ketovaleric acid, fructose, ethylene glycol, diethylene glycol and triethylene glycol.

[0125] Furthermore, for the same organic compound, it is observed that the extraction rate of the Group VIII and / or Group VIB metal can be improved by using a higher concentration of this organic compound in the extraction solution. It is generally observed that the extraction rate of the Group VIII and / or VIB metal can be increased by using an extraction solution with a higher concentration of the organic compound. but that the arsenic extraction rate remains stable. The concentration of organic compound in the extraction solution is preferably between 0.5 and 1 mol / L.

[0126] The choice of certain organic compounds, combined with a high concentration of this organic compound in the extraction solution, thus makes it possible to significantly increase the extraction rate of the Group VIII and / or Group VIB metal while observing a stable arsenic extraction rate. This is particularly the case when the organic compound is chosen from acetic acid, oxalic acid, citric acid, γ-ketovaleric acid, fructose, ethylene glycol, diethylene glycol, and triethylene glycol, combined with an organic compound concentration in the extraction solution of between 0.5 and 1 mol / L.

[0127] In one embodiment according to the invention, the extraction solution may also contain phosphorus. The presence of phosphorus promotes the extraction of metals, and in particular molybdenum, due to the high stability of the heteropolyanions that this metal forms with phosphorus. The addition of phosphorus in the form of phosphoric acid (H3PO4) also lowers the pH of the solution, which is also generally beneficial for the extraction of metals contained in the source catalyst. Other mineral acids besides phosphoric acid can also be used, in particular nitric acid or boric acid. It should be noted that the use of sulfuric acid, a conventional metal extraction agent, is not recommended. Indeed, sulfuric acid is not a selective extraction agent and extracts a large amount of arsenic along with the metals of Group VIII and / or VIB. The extraction solution therefore preferably does not contain sulfuric acid.

[0128] In one embodiment according to the invention, the extraction solution may also contain an oxidant to promote the extraction of metals. Preferably, the oxidant contained in the extraction solution is hydrogen peroxide. When an oxidant is present, the concentration is generally between 0.1 and 5.0 mol / L.

[0129] Generally, the operating conditions of the extraction step according to the invention are chosen so as to maximize the extraction of Group VIII and / or VIB metals contained in the source catalyst, while minimizing the dissolution of contaminants, and in particular arsenic from said source catalyst, and limiting as much as possible the quantity of organic compound so that the latter is not in excessive excess relative to the optimal quantity of organic compound required for the impregnation step to obtain high-performance catalysts. The aim is also to minimize the quantity of extraction solution to be used, in order to obtain the most concentrated metal solution possible at the end of the extraction: this limits the need to concentrate the solution before using it in the impregnation solution or as an impregnation solution.

[0130] Contact is made with the extraction solution under the following conditions:

[0131] The temperature is generally between 0 and 300°C, preferably between 10 and 100°C, and more preferably between 15 and 40°C. Particularly preferably, the temperature is ambient temperature.

[0132] The pressure is generally between atmospheric pressure and 20 bars (2 MPa), in particular between atmospheric pressure and 10 bars (1 MPa).

[0133] The duration of contact per extraction step is generally between 1 minute and 20 hours, preferably between 5 and 300 minutes, and preferably between 5 and 120 minutes.

[0134] The quantity of extraction solution used in this step is preferably as small as possible to obtain the desired effect, as indicated above. Preferably, this step is carried out by contacting the source catalyst with a volume of said solution between 1.5 and 60 times the volume of the source catalyst. Preferably, the volume of said solution is between 2 and 30 times the volume of the source catalyst, and more preferably between 2 and 20 times the volume of the source catalyst, and particularly preferably between 2 and 10 times the volume of the source catalyst.

[0135] When the tool(s) performing the contact do not have heating equipment, and the contact temperature is regulated by the temperature of the extraction solution. It may therefore be at ambient temperature, or have been heated, for this specific contact step. It may also be at a given temperature, particularly above ambient temperature, because it originates, at least in part, from the recycling of liquid effluents produced during its use as an impregnation solution and already being within this temperature range.

[0136] According to the present invention, "extraction" is understood to mean that there is an extraction step, but that the extraction can be carried out by one extraction operation or a plurality of successive extraction operations.

[0137] All contact methods, whether single-step or multi-step following a co-current, counter-current, or cross-current flow, are possible for implementing the continuous extraction step. The extraction step includes contacting the extraction solution with the source catalyst, followed by a solid / liquid separation step to obtain, on the one hand, a leached catalyst depleted in Group VIII and / or VIB metal(s) but containing most of the arsenic, and, on the other hand, the extraction solution enriched in at least one Group VIB metal and / or at least one Group VIII metal and containing as little arsenic as possible.

[0138] The contacting of the extraction solution with the source catalyst can be done by any method known to those skilled in the art, for example by suspending the source catalyst in the extraction solution by means of a rotary agitator or by fluidization, or by percolation of the leaching solution through a fixed bed containing the source catalyst.

[0139] The liquid / solid separation can be carried out by any method known to those skilled in the art, for example by sedimentation, filtration, dewatering (e.g., gravity dewatering), and / or centrifugation. The remaining solid residue can be washed with the extraction solvent and / or water. It can also be dried.

[0140] According to one embodiment, when the source catalyst contains only a metal from group VIB or a metal from group VIII, respectively, only a metal from group VIB or a metal from group VIII is extracted from the catalyst. According to another embodiment, when the source catalyst contains at least one metal from group VIB and at least one metal from group VIII, either only the metal from group VIB or group VIII, respectively, or both the metal from group VIB and the metal from group VIII are extracted.

[0141] At the end of the extraction step, on the one hand, a leached catalyst depleted in metal / metals but containing most of the arsenic is obtained, and, on the other hand, the extraction solution is enriched in at least one metal from group VIB and / or at least one metal from group VIII and containing as little arsenic as possible.

[0142] Preferably, the residual content of group VIII and / or VIB metals of the metal / metals depleted catalyst (sum of the contents of the different metals contained in the leached catalyst expressed as oxide) is less than 10% by weight, preferably less than 5% by weight and most preferably less than 2% by weight relative to the weight of the metal / metals depleted catalyst.

[0143] The extraction rate of the metal from Group VIII is generally greater than 50%, preferably greater than 60%, and preferably greater than 70%. Preferably, the extraction rate of the metal from Group VIII is between 50 and 100%, preferably between 60 and 100%, and preferably between 70 and 100%.

[0144] The extraction rate of the metal from group VIB is generally greater than 50%, preferably greater than 60%, and preferably greater than 70%. Preferably, the extraction rate of the metal from group VIB is between 50 and 100%, preferably between 60 and 100%, and preferably between 70 and 100%.

[0145] The extraction rate corresponds to the mass of the metal / metals extracted in the extraction solution relative to the mass of metal / metals initially present on the source catalyst.

[0146] The arsenic extraction rate is preferably less than 30%, preferably less than 20%, preferably less than 15% and even more preferably less than 10%.

[0147] Titanium and iron contaminants, like arsenic, are generally poorly extracted and remain largely in the leached catalyst. Similarly, a low content of phosphorus (from the source catalyst when present) and aluminum (from the source catalyst support) can be observed in the extraction solution. The extraction rates of phosphorus, aluminum, titanium, and iron are preferably less than 30%, preferably less than 20%, preferably less than 15%, and even more preferably less than 10%, respectively.

[0148] The contaminants vanadium, nickel (contaminant from the feed and not from the active phase), silicon, sodium, calcium and potassium are distributed between the extraction solution and the leached catalyst. The extraction rate of vanadium, nickel (contaminant), silicon, sodium, calcium and potassium is generally between 20 and 70%, preferably between 25 and 65%, and preferably between 25 and 60%.

[0149] The extraction rate corresponds to the mass of the contaminant in the extraction solution relative to the mass of the contaminant initially present on the source catalyst.

[0150] Since the contaminants vanadium, nickel (contaminant from the feed and not from the active phase), silicon, sodium, calcium and potassium are distributed between the extraction solution and the leached catalyst, they can therefore be found in significant quantities in the extraction solution.

[0151] In this case, their levels in the impregnation solution can be reduced by dilution (for example, with another extraction solution containing no or fewer contaminants). According to another embodiment, a metal from group VIII and / or VIB can also be added to the extraction / impregnation solution containing too many contaminants.

[0152] Step(s) of treatment of the extraction solution before impregnation (optional)

[0153] Before its use as an impregnation solution, the extracted metal(s) solution may be subjected to at least one treatment step selected from at least one of the following: purification, concentration, dilution, modification of the solution's composition by the addition or removal, total or partial, of at least one compound. The extracted metal(s) remain in the liquid phase during these treatments. Purification

[0154] The extracted metal(s) solution may be subjected to a purification step. The purpose of purification is to remove all or part of any impurities that may be present in the metal solution, particularly those originating from impurities potentially present on the source catalyst or related to partial dissolution of the catalyst support. Purification may be carried out in a single step or in several successive steps.

[0155] If the extracted metal(s) solution contains suspended solids after the final liquid / solid separation step, any known method for removing these suspended solids may be used. Preferably, this removal is carried out by filtration (e.g., microfiltration and ultrafiltration using a cross-flow filter). Other methods include centrifugation, coagulation, or sedimentation.

[0156] For dissolved impurities, such as for example arsenates or arsenites, all known methods may be used, in particular and preferably, sorption on solid, precipitation and solvent extraction, taking care not to remove at the same time the metals of interest which have been extracted. • Concentration

[0157] The extracted metal(s) solution, optionally purified, may be subjected to a concentration step. This step consists of concentrating the extracted metal(s) solution by removing a portion of the solvent and, optionally, all or part of the organic compound contained in the metal solution. This step may be necessary if the metal concentrations are too low compared to the concentrations required for impregnation. Any known method for removing a portion of a solvent from a solution is considered. The concentration may be carried out in a single step or in several successive steps. All or part of the solvent, with or without organic compound, extracted from the metal solution, may be recycled in the process according to the invention as an extraction solution.

[0158] Preferably, and particularly when the metal solution is aqueous, concentration is achieved by evaporation. In this case, neutralization is preferably carried out so that the effluent enters the evaporator at a pH of 5 to 7. This pH control helps limit co-distillation, unless it is desired for the co-removal of the solvent and part of the organic compound, and also to minimize the precipitation of metal oxides. Preferably, all or part of the distillate can be recycled in the process according to the invention as an extraction solution.

[0159] When only the removal of part of the solvent is desired, in addition to evaporation concentration, the preferred techniques are membrane techniques, and, in a highly preferred manner, nanofiltration, reverse osmosis and pervaporation, solvent extraction or cryoconcentration.

[0160] When it is desired to remove solvent and organic compound(s) when they are used, a preferred technique is evaporation concentration. • Adjustment of the composition of the metallic solution

[0161] The extracted metal(s) solution, possibly purified and / or concentrated, may undergo a composition adjustment step. This step consists of modifying the metal solution by adding and / or removing certain constituents. Metal precursors and / or phosphorus precursors and / or organic additives may be added. Organic compounds used for metal extraction may also be removed, in whole or in part, if necessary. The objective is to obtain a metal solution whose composition corresponds to that desired for the impregnation solution used in the synthesis of a new catalyst.

[0162] Even if it is desired that the catalyst obtained according to the invention has a formulation identical to that of the source catalyst, the ratios between metals of the metal solution are potentially to be adjusted, on the one hand because the purification of the catalyst can modify the initial metal contents of the source catalyst, and on the other hand because the extraction step can induce different extraction rates for each of the metals.

[0163] The adjustment of the ratios between metals is carried out either by adding a makeup solution containing one or more of said metals, or by directly dissolving one or more metal precursors in the solution of extracted metal(s), the latter alternative being preferred. The molar ratio of Group VIII metal to Group VIB metal in the metal solution after this adjustment step is generally between 0.1 and 0.8, preferably between 0.15 and 0.6.

[0164] By way of example for metallic precursors, molybdenum sources may include oxides and hydroxides, molybdic acids and their salts, in particular ammonium salts such as ammonium molybdate, ammonium heptamolybdate, phosphomolybdic acid (H3PMoi2O4o), and their salts, and possibly silicomolybdic acid (H4SiMoi2O4o) and its salts. Molybdenum sources may also be any heteropolycompound of the Keggin, lacunar Keggin, substituted Keggin, Dawson, Anderson, and Strandberg types, for example. Molybdenum trioxide and heteropolycompounds of the Keggin, lacunar Keggin, substituted Keggin, and Strandberg types are preferably used.

[0165] The tungsten precursors that can be used are also well known to those skilled in the art. For example, among the sources of tungsten, oxides and hydroxides, tungstic acids and their salts, in particular ammonium salts such as ammonium tungstate, ammonium metatungstate, and other tungsten-like acids, can be used. Phosphotungstic acid and its salts, and possibly silicotungstic acid (H4SiWi2O4O) and its salts, are used. Tungsten sources can also include any heteropolycompound of the Keggin, lacunar Keggin, substituted Keggin, or Dawson type, for example. Ammonium oxides and salts, such as ammonium metatungstate or heteropolyanions of the Keggin, lacunar Keggin, or substituted Keggin type, are preferred.

[0166] The cobalt precursors that can be used are advantageously chosen from among oxides, hydroxides, hydroxycarbonates, carbonates, and nitrates, for example. Cobalt hydroxide and cobalt carbonate are preferred. Cobalt acetoacetate may also be used.

[0167] The nickel precursors that can be used are advantageously chosen from among oxides, hydroxides, hydroxycarbonates, carbonates and nitrates, for example. They can also be nickel acetoacetate.

[0168] If the phosphorus / metal ratio of the extracted metal(s) solution is lower than that desired for the impregnation solution, a phosphorus precursor, identical or different from that optionally used in the extraction step, may be added to the extracted metal(s) solution. This will be the case, in particular, when no phosphorus compound / precursor has been added to the extraction solution, or when the phosphorus has been consumed, at least in part, by the support, if it contains alumina, to form aluminophosphates. In this case, the molar ratio of phosphorus to the metal of group VIB is between 0.1 and 2.5 mol / mol, preferably between 0.1 and 2.0 mol / mol, and even more preferably between 0.1 and 1.0 mol / mol or between 0.15 and 0.8 mol / mol, or between 0.2 and 0.6 mol / mol.

[0169] The preferred phosphorus precursor is phosphoric acid H3PO4, but its esters and salts such as ammonium phosphates are also suitable, as are polyphosphates. Phosphorus can also be introduced along with the element(s) of group VIB in the form of Keggin, lacunar Keggin, substituted Keggin, or Strandberg-type heteropolyanions.

[0170] The addition of an organic additive to hydrotreating / hydroconversion catalysts has been recommended by those skilled in the art to improve their activity. These additives are known to improve the dispersion of metals on the surface of the support and / or to play a beneficial role during the sulfidation of the catalysts. Thus, one or more organic additives well known to those skilled in the art can be advantageously added at this stage. Generally, the quantity of each organic additive added is defined so that the molar ratio of additive to metals is between 0.1 and 1 in the impregnation solution.

[0171] Patent FR3083134 describes examples of suitable organic additives that can be used in aqueous form, and that can therefore be added to the solution impregnation. Patent FR3083131 also describes examples of suitable organic additives, but which will rather be added separately, either as pre-impregnation or post-impregnation of the support.

[0172] The extracted metal(s) solution may contain an excess of organic compound relative to the desired impregnation solution. The ratios between organic compound and metals can be adjusted in two ways. The first way is to add a concentrated solution of metal precursors, or to dissolve these metal precursors directly to achieve the desired ratios. In this case, the final catalyst obtained will comprise a mixture of recycled and virgin metals.

[0173] If the excess organic compound is too large to use the first method (i.e., the quantity of recycled metals incorporated into the final catalyst is not significant, for example, less than 5% by weight of the total quantity of metals), the second method consists of removing all or part of the excess organic compound from the metal solution. In this case, the organic compound can be recycled in the extraction step. For this purpose, any method known to those skilled in the art for separating an organic molecule from a metal solution is considered. The concentration of the excess organic compound can be reduced, for example, by evaporation, liquid-liquid extraction, adsorption, or membrane separation. Impregnation stage

[0174] The extracted metal(s) solution, possibly previously subjected to one or more of the treatments described below, can be used for the preparation of a new catalyst. According to the process of the invention, the support is impregnated with an impregnation solution derived from said extracted metal(s) solution to obtain an impregnated substrate, said extracted metal(s) remaining in the liquid phase from extraction until impregnation.

[0175] According to the present invention, the term "support" (which will be impregnated with the impregnation solution from the extracted metal / metal(s) solution) includes a "new" oxide support, but also a support that has already been impregnated with another impregnation solution - we speak of a pre-impregnated support - or a support that is in fact a catalyst (a support containing metals) but which contains an insufficient quantity of metals, such as a used or regenerated catalyst.

[0176] Impregnation can be carried out by any known method, such as ion exchange, dry impregnation, excess impregnation, vapor deposition, etc. Impregnation can take place in one step or in several successive steps.

[0177] According to a preferred method, the impregnation of said substrate with the impregnation solution is carried out by over-impregnation or by dry impregnation. The impregnation Impregnation at equilibrium or in excess consists of immersing the support or catalyst in a volume of solution (often significantly) greater than the porous volume of the support or catalyst. Dry impregnation, on the other hand, consists of introducing a volume of impregnation solution equal to or slightly less than the porous volume of the support or catalyst. Dry impregnation allows for the deposition of all the constituents of the impregnation solution onto a given support or catalyst. The impregnation step can advantageously be carried out by one or more impregnations in excess of the solution or, preferably, by one or more dry impregnations, and, for example, by a single impregnation in excess, using the impregnation solution. According to the present invention, "impregnation" refers to the fact that there is an impregnation step, but that the impregnation can be carried out by one or more successive impregnation operations.

[0178] The impregnation is carried out at a temperature generally between 10°C and 95°C, at a pressure between atmospheric pressure and 20 bar (2 MPa), preferably at atmospheric pressure, and for a duration preferably between 1 minute and 20 hours, preferably between 1 and 300 minutes. The impregnation is preferably carried out at a temperature between 10°C and 60°C, preferably at ambient temperature.

[0179] Advantageously, after each impregnation step, the impregnated support or catalyst is allowed to mature. Maturation allows the impregnation solution to disperse homogeneously within the support or catalyst.

[0180] Each maturation step is advantageously carried out at atmospheric pressure, in a water-saturated atmosphere and at a temperature between 17°C and 50°C, and preferably at ambient temperature. Generally, a maturation time of between 10 minutes and 48 hours, and preferably between 30 minutes and 6 hours, is sufficient.

[0181] Advantageously, the contact impregnation step is followed by a drying step at a temperature below 200°C, preferably between 50 and 180°C, more preferably between 70 and 150°C, and most preferably between 75 and 130°C. The drying step is preferably carried out for a duration of between 10 minutes and 24 hours. Longer durations are not excluded, but do not necessarily provide any improvement. The drying step can be carried out by any known technique. It is advantageously carried out at atmospheric pressure or reduced pressure. Preferably, this step is carried out at atmospheric pressure. It is advantageously carried out using air or any other hot gas. Preferably, the gas used is either air or an inert gas. such as argon or nitrogen. Preferably, drying is carried out in the presence of nitrogen and / or air and is advantageously performed in a flow bed.

[0182] According to one embodiment, the drying is advantageously carried out so as to retain preferably at least 30% by weight of the organic additive introduced during any adjustment of the organic compound after the extraction step and / or introduced during the impregnation step. Preferably, this quantity is greater than 50% by weight and even more preferably greater than 70% by weight, calculated on the basis of the carbon remaining on the catalyst.

[0183] According to one variant, the drying is advantageously carried out so as to retain preferably at least 30% by weight of the organic extraction compound introduced during the extraction step, preferably this quantity is greater than 50% by weight and even more preferably greater than 70% by weight, calculated on the basis of the carbon remaining on the catalyst.

[0184] Optionally, the drying process can be followed by a calcination step. This might be the case, for example, if it is desired to remove all or part of one or more organic extraction compounds. According to this variant, after the drying step, a calcination step is carried out at a temperature between 200°C and 600°C, preferably between 250°C and 550°C, under an inert atmosphere (nitrogen, for example) or under an atmosphere containing oxygen (air, for example). The duration of this heat treatment is generally between 0.5 hours and 16 hours, preferably between 1 hour and 5 hours. After this treatment, the active phase is generally in oxide form, and the heteropolyanions are thus transformed into oxides. Similarly, the catalyst contains little or no organic extraction compound or organic additive.However, the introduction of the organic additive during its preparation increased the dispersion of the active phase, thus leading to a more active catalyst.

[0185] Preferably, the catalyst is not subjected to calcination.

[0186] In the embodiment in which the impregnation step is carried out via at least two impregnation cycles, each impregnation is advantageously followed by drying and possibly calcination.

[0187] The "new" oxide support which will be impregnated with the impregnation solution from the extracted metal(s) solution can be of the same nature as the support of the source catalyst, a description of which has already been given above.

[0188] The support may also contain at least a portion of metal(s) VIB and VIII, and / or at least a portion of phosphorus and / or at least a portion of sulfur and / or at least a portion of the organic additive(s) other than those that may be introduced during the step of adjusting the composition of the metal solution and / or the impregnation stage. They are introduced, for example, during the preparation of the substrate. This is then referred to as a "pre-impregnated" substrate.

[0189] It is also possible to add one or more metals to the support already impregnated with the impregnation solution according to the invention. This is then referred to as a "post-impregnated" support.

[0190] In both cases, “pre-impregnated” or “post-impregnated” support, the goal is the same: it is to adjust the metal content of the final catalyst, either by adding a certain quantity of the metal(s) present in the impregnation solution according to the invention, or by adding one or more other metals in a separate step, with another impregnation solution in particular, before and / or after the impregnation step with the impregnation solution of the invention.

[0191] A catalyst already containing one or more metals can also be brought into contact with the solution of extracted metal(s). This may be a catalyst that has been depleted of metals, and in particular a spent catalyst itself, possibly regenerated and then optionally rejuvenated.

[0192] The active phase of the recycled catalyst targeted by the process according to the invention is generally of the type already described above for the so-called source catalyst.

[0193] It should be noted that the new catalyst may have a different formulation from the source catalyst used to recover the metals, and different quantities and ratios of metals: thus, a spent catalyst with a high metal content can, according to the invention, be used to produce a catalyst with a lower metal content (or vice versa). This makes it possible, where appropriate, to avoid a solution concentration step after extraction or at least to reduce its intensity / duration. The recycled catalyst can then be used differently (on different hydrocarbon feedstocks) than the source catalyst from which it is derived (for example, a catalyst with 20% wt% Mo expressed as MoO3 relative to the dry catalyst weight can be used for the hydrotreating of distillates, whereas a catalyst with a lower Mo content, of 10% wt% Mo expressed as MoO3, can be used for the hydrotreating of naphtha).Thus, a source catalyst can be used that does not have the same function as the recycled catalyst to be produced, as long as they have at least one metal in common (hydrotreating catalyst, hydrocracking catalyst, Fischer-Tropsch catalyst), or that has the same function (hydrotreating catalyst in both cases for example).

[0194] It should also be noted that the new catalyst can be post-additized, that is to say that an additional impregnation step of one or more organic additives can be carried out, the function of which is to increase the catalytic activity compared to non-additized catalysts, before the final optional sulfidation, it being understood that, preferably, no calcination step is carried out after its introduction.

[0195] The quantity of recycled metals contained in the new catalyst is between 1% and 100% by weight of the metals contained in the new catalyst, preferably between 10% and 100% by weight, preferably between 20% and 100% by weight, and even more preferably between 50% and 100% by weight relative to the weight of the new catalyst.

[0196] Before use, the new catalyst may undergo an optional sulfidation step. Sulfuration is preferably carried out in a sulfur-reducing medium, i.e., in the presence of H₂S and hydrogen, in order to transform metal oxides into sulfides such as, for example, MoS₂ and Co₉S₈. Sulfuration is performed by injecting a stream containing H₂S and hydrogen, or a sulfur compound capable of decomposing into H₂S in the presence of the catalyst and hydrogen, onto the catalyst. Polysulfides such as dimethyl disulfide (DMDS) are H₂S precursors commonly used for sulfiding catalysts. The sulfur may also be supplied by the feedstock. The temperature is adjusted so that H₂S reacts with the metal oxides to form metal sulfides.This sulfidation can be carried out in situ or ex situ (inside or outside the reactor) of the reactor of the hydrotreating or hydroconversion process according to the invention at temperatures between 200 and 600°C, and more preferably between 300 and 500°C.

[0197] According to one variant, at least part of the impregnation solution can be reused after the support has been impregnated, in particular as a top-up for the extraction solution. This limits the consumption of solvent and (optional) organic compound in the process. Examples

[0198] We start from a spent catalyst called CoMoP, containing molybdenum, cobalt and phosphorus deposited on an alumina support used in a hydrotreating process and which has been contaminated with arsenic. It has previously been regenerated under a flow of dry air at 450°C for 4 hours.

[0199] The regenerated catalyst contains molybdenum, phosphorus, and cobalt. The catalyst composition is expressed as oxides and reported by mass of dry catalyst: 20.3 wt% MoO3 (13.5 wt% molybdenum), 4.1 wt% CoO (3.2 wt% cobalt, i.e., a Co / Mo molar ratio of 0.39), and 3.4 wt% P2O5 (1.5 wt% phosphorus, i.e., a P / Mo molar ratio of 0.34). It also contains 8400 ppm wt% of arsenic.

[0200] Extraction with aqueous solution containing 0.15 mol / L of citric acid:

[0201] A step of extracting molybdenum and cobalt metals from this regenerated catalyst is carried out on a laboratory scale: 30 g of this contaminated regenerated catalyst (called source catalyst), previously ground to a particle size of Between 100 and 300 microns, 75 mL of extraction solution are introduced into a flask. The extraction solution is an aqueous solution containing 0.15 mol / L of citric acid. The mixture is stirred at room temperature at 200 rpm using a magnetic stir bar for 6 hours. The mixture is then filtered through sintered glass with a porosity of 5 to recover a polymetallic solution and a solid residue. Analysis of the solution shows that it contains 30.5 g / L of molybdenum, 7.2 g / L of cobalt, and 0.57 g / L of arsenic. The calculated extraction rates of molybdenum and cobalt are therefore 56% and 55%, respectively, and the extraction rate of arsenic is 17%.

[0202] 7.6 mL of leaching solution is taken and 2.58 g of oxide is added molybdenum (MoO3), 0.63 g of cobalt hydroxide (Co(OH)2), 0.60 g of phosphoric acid (H3PO4 100% pure), and 1.42 g of citric acid (100%) are used to prepare 8 mL of impregnation solution, which is then impregnated onto 10 g of alumina (dry impregnation). After 16 hours of maturation at room temperature in a humid atmosphere and 2 hours of drying at 120°C, the resulting recycled catalyst A contains 21 wt% MoO3 and the molar ratios Co / Mo 0.38, P / Mo 0.3, and AC / Mo 0.4.

[0203] Extraction with aqueous solution containing 1 mol / L of citric acid:

[0204] A step for extracting molybdenum and cobalt from this regenerated catalyst is carried out on a laboratory scale: 30 g of this contaminated regenerated catalyst (referred to as the source catalyst), previously ground to a particle size between 100 and 300 microns, and 75 mL of extraction solution are introduced into a flask. The extraction solution is an aqueous solution containing 1 mol / L of citric acid. The mixture is stirred at room temperature at 200 rpm using a magnetic stir bar for 6 hours. The mixture is then filtered through sintered glass with a porosity of 5 to recover a polymetallic solution on the one hand and a solid residue on the other. Analysis of the solution shows that it contains 48.2 g / L of molybdenum, 11.3 g / L of cobalt, and 0.64 g / L of arsenic. The calculated extraction rates of Mo and Co are therefore 88% and 87% respectively, and the extraction rate of arsenic is 19%.

[0205] 7.6 mL of leaching solution is taken and 2.38 g of oxide is added molybdenum (MoO3), 0.58 g cobalt hydroxide (Co(OH)2), 0.60 g phosphoric acid (H3PO4 100% pure), and 0.19 g citric acid (100%) are used to prepare 8 mL of impregnation solution, which is then impregnated onto 10 g of alumina (dry impregnation). After 16 hours of maturation at room temperature in a humid atmosphere and 2 hours of drying at 120°C, the resulting recycled catalyst B contains 21 wt% MoO3 and has the following molar ratios: Co / Mo 0.38, P / Mo 0.3, and AC / Mo 0.4.

[0206] Increasing the concentration of citric acid thus makes it possible to increase the extraction rate of the metals Mo and Co without significantly increasing that of arsenic.

[0207] Catalyst B, which contains less arsenic, exhibits a higher level of performance than catalyst A, which contains more arsenic.

Claims

Demands

1. A process for producing a catalyst comprising at least one metal from group VIB and / or at least one metal from group VIII, optionally phosphorus and / or sulfur, and an oxide-based support(s), characterized in that said process comprises recycling at least a portion of the metal(s) from group VIB and / or group VIII from a source catalyst comprising at least one metal from group VIB and / or at least one metal from group VIII common to the catalyst to be produced, said source catalyst being contaminated with arsenic, the process comprising: - an extraction of the metal from group VIB and / or the metal from group VIII of said source catalyst by an extraction solution comprising at least one organic compound having complexing properties selected from acetic acid, oxalic acid, citric acid, γ-ketovaleric acid, fructose, ethylene glycol, diethylene glycol and triethylene glycol,the concentration of each organic compound in the extraction solution being between 0.5 and 1 mol / L, to obtain a solution of the extracted metal(s), then - impregnation of the support with an impregnation solution derived from said solution of extracted metal(s), to obtain an impregnated substrate, said extracted metal(s) remaining in liquid phase from extraction until impregnation.

2. A process according to claim 1, wherein the source catalyst is contaminated with nickel and / or vanadium and / or iron and / or titanium and / or silicon and / or calcium and / or sodium and / or potassium and / or chlorine.

3. A method according to any one of the preceding claims, wherein the source catalyst is a used catalyst that has been previously regenerated and / or rejuvenated.

4. A process according to any one of the preceding claims, wherein the extraction solution comprises a mineral acid selected from phosphoric acid, nitric acid or boric acid.

5. A process according to any one of the preceding claims, wherein the source catalyst is subjected to at least one pretreatment step before the extraction step selected from oil removal, regeneration, grinding or water washing.

6. A process according to any one of the preceding claims, wherein the extracted metal / metal(s) solution is subjected to at least one treatment step before impregnation of the support, said treatment step being selected from a concentration, a dilution and / or a modification of the composition of the solution by addition or removal, total or partial, of at least one compound of said solution.

7. A process according to any one of the preceding claims, wherein the impregnation of the support with an impregnation solution is carried out from the solution of extracted metal(s) and a supplement of at least one of the metals of group VIII / VIB, and optionally of phosphorus and / or organic additive(s).

8. A method according to any one of the preceding claims, wherein at least part of the impregnation solution is reused after the support has been impregnated as a supplement to the extraction solution.

9. A method according to any one of the preceding claims, wherein the support on which the impregnation is carried out with the impregnation solution from the extracted metal / metal(s) solution is pre-impregnated or post-impregnated with an impregnation solution or is a metal-depleted catalyst.

10. A process according to any one of the preceding claims, wherein said impregnated substrate obtained after impregnation is subjected to a drying step, optionally to a calcination step and optionally to a sulfidation step.

11. A process according to any one of the preceding claims, wherein the source catalyst is contaminated with arsenic and the extraction rate of the metal from Group VIII or Group VIB is respectively greater than 50% by weight and the extraction rate of arsenic is less than 30% by weight, the extraction rate being the mass of the metal(s) extracted and of the arsenic extracted in the extraction solution relative to the mass of the metal(s) present and of the arsenic initially present on the source catalyst.