Zero waste technology for spent catalyst recycling by hydro metallurgy pyrometallurgy combination

Abstract

Development of commercially proven Technology and manufacturing process using Hydro and Pyro Metallurgy combination to produce Pure Vanadium Pentoxide for Electrolyte of VRFB battery and for ingredient of Alloy steels, Calcium Molybdate, Ferro Nickel, Refractory Cement for Castables, Synthetic Slag for use as ingredient for Stainless Steel and Alloy steel, Ammonium Para Tungstate for Tungsten Metal powder and Cobalt Oxide for use in New age batteries by Recycling and converting all solid components of Spent Ebulating bed / ARDS catalyst from Oil refineries as well as other spent catalysts from Petroleum and Fertilizer plants spread across the globe to saleable products. This solves the issue of safe environment friendly disposal of the spent catalysts after their life cycle, which are Hazardous wastes as per Basel Convention, it also gives a secondary source of valuable & noble metals like Vanadium, Molybdenum, Nickel, Cobalt, Tungsten etc. to reduce polluting mining activities of these otherwise scarce metals in mother earth.

Description

ZERO WASTE TECHNOLOGY FOR SPENT CATALYST RECYCLING BY HYDRO METALLURGY PYROMETALLURGY COMBINATION FIELD OF INVENTION

[0001] The present invention provides a process by combination of Hydro and Pyro Metallurgy to produce Pure Vanadium Pentoxide for Electrolyte of VRFB battery and for ingredient of Alloy steels, Calcium Molybdate, Ferro Nickel, Synthetic Slag for use as ingredient for Stainless Steel and Alloy steel, Calcium Aluminate refractory cement for castables, Ammonium Para Tungstate for Tungsten Metal powder and Cobalt Oxide for use in New age batteries by Recycling and converting all solid components of Spent catalyst from Oil refineries, Petroleum and Fertilizer plants spread across the globe to saleable products. BACKGROUND OF THE INVENTION

[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

[0003] Catalysts bearing single or combination of metals embedded in alumina (Al2O3) matrix are used in refining processes of Crude Oil in Oil refineries and Petrochemical plants across the globe. At the end of their service life, they get contaminated by Coke, S and / or other heavy metals absorbed from the Crude oil and lose their efficiency and hence replaced by new catalysts. These spent catalysts contain leachable heavy metals like Nickel, Molybdenum, Cobalt, Vanadium etc. and hence they are Hazardous in nature and needs to be treated / disposed as per Basel convention norms.

[0004] Presently there are few recycling players in the world, who use either Pyrometallurgy as their process or Hydrometallurgy to reclaim these value metals partially or in impure form, which cannot be used for critical applications like batteries or high grade steel. Besides, all hydrometallurgy process generates large quantity of Solid Hazardous waste, which needs safe disposal in turn due to residual heavy metal content in them.

[0005] CN105274344A relates to a method for recycling vanadium and molybdenum from a waste petroleum catalyst, and belongs to the technical field of petrochemical industry. The method comprises air-burning and ball-removing, ball-milling, soda roasting-water leaching, aluminum removing, molybdenum precipitating and enriching molybdenum by ion exchange.

[0006] KR20080105677A relates to a method for manufacturing a catalytic material from a desulfurization waste catalyst in oil refineries to enhance using rate of waste, to remove environmental pollutant and to remove effectively vanadium.

[0007] CZ282409B6 relates to a method of pyrometallurgically re-processing used deactivated catalysts, in particular from petrochemical or fuel processing of crude oil and from cleaning waste gases. The method is based on the fact that used catalysts containing metals of group VI.B and VIII on alumina or aluminosilicate together with catalysts containing metals of the group of platinum on alumina or aluminosilicate after possible thermal pre-treatment and in the presence of a reducing agent and possibly a flux agent are mixed with calcium oxide in a weight ratio of CaO:Al2O3= 2:3 to 3:2 and the resulting mixture is melted at a temperature of 1,600 to 1,700 degrees C while the clinker is gradually separated, and the separated metal which is an alloy of the metals of group VI B and VIII and metal of the group of platinum is then processed hydro-metallurgically.

[0008] CN1207409C the present invention discloses technology for extracting vanadium and / or molybdenum by adopting a wet method and using spent catalysts as raw material, which contain alumina supporters of vanadium, molybdenum, nickel, etc. and are discharged from petrochemical engineering industry. he present invention has the advantages of high recovery rate of vanadium and molybdenum, strong treating capability and favorable technical index and benefit, and the product quality reaches the national standard

[0009] CN111321296A the invention provides a method for recovering vanadium and nickel from a waste petroleum catalyst, belonging to the field of petrochemical metallurgy. The method comprises the following steps: roasting, vacuum volatilization, dissolving and purifying to obtain vanadium and nickel metal.

[0010] While several approaches have been tried in the past, none of the present approaches provides a desired solution as to effectively combine the Hydro and Pyro Metallurgy processes, to obtain pure compounds. Therefore, there is a long-standing need in the art of an improved process for 100% extraction of the Vanadium and Molybdenum to produce pure metal compounds.

[0011] Based on the above it is desired to address the above mentioned disadvantages or other shortcomings or at least provide a useful alternative. OBJECTS OF THE INVENTION

[0012] The primary objective of the present invention is to provide a newly developed technology and process which combines Hydro metallurgy and Pyro metallurgy.

[0013] Another objective of the present invention is to provide a process for 100% extraction of the Vanadium and Molybdenum to produce pure metal compounds namely, Vanadium Pentoxide, which is used to make electrolyte for VRFB batteries, Ferro Vanadium for steel making and Calcium Molybdate for Stainless steel and Alloy steel manufacturing.

[0014] It is an object of the present disclosure to provide a process wherein all the elements of the spent catalyst is converted into saleable products, leaving no Hazardous waste for disposal.

[0015] It is an object of the present disclosure to provide a process which solves the issue of safe environment friendly disposal of the spent catalysts after their life cycle, which are Hazardous wastes as per Basel Convention.

[0016] Yet another object of the present disclosure to provide a secondary source of valuable & noble metals like Vanadium, Molybdenum, Nickel, Cobalt, Tungsten etc. to reduce polluting mining activities of these otherwise scarce metals in mother earth. SUMMARY

[0017] Various embodiments of present disclosure relate to a process for production of mono-aromatics from clarified oil. More particularly, it relates to a process that includes subjecting the feedstock to aromatic extraction by contacting the feedstock with a solvent in an aromatic extraction unit followed by hydrocracking to obtain mono-aromatics.

[0018] According to one aspect of the present disclosure, a process for recycling the spent catalyst is disclosed. The process comprises the following steps: (a) exposing the spent catalyst to a temperature ranging from 700oC to 1500oC to obtain a roasted mix and a vapor stream; (b) subjecting the roasted mix to leaching to obtain a metallic component and a non-metallic component, said leaching being done in presence of NaOH and Na2CO3at a temperature ranging from 130oC to 300oC to and at a pressure ranging from 5 to 40 kg / cm2 for a time period ranging from 30 minutes to 10 hour; (c) subjecting the metallic component to precipitation to obtain a metal compound, said metal compound comprising Ammonium Metavanadate (AMV), Calcium Molybdate, Calcium Tungstate or combinations thereof; (d) subjecting the non-metallic component to pyrometallurgic treatment to obtain a metal alloy and a synthetic slag, said treatment being done in presence of CaO and at a temperature ranging from 1200oC to 1500oC for a time period ranging from 1 hour to 8 hours.

[0019] In some embodiments, the spent catalyst is exposed to a temperature ranging from 1280-1350oC to obtain a roasted mix and a vapor stream.

[0020] In some embodiments the step of leaching comprises contacting the roasted mix with NaOH and Na2CO3in presence of water for a time period ranging from 2.5-5 hrs.

[0021] In some embodiments the step of leaching comprises that the Pre-reacted mix of roasted spent catalyst and Na2CO3at 900℃ – 1200℃ is leached in water

[0022] In some embodiments the final pH of the leached slurry ranges from 9-10.

[0023] In some embodiments, in the step of leaching the solid to liquid ratio is 1: 3.

[0024] In some embodiments the high temperature Pre-reacted mix of roasted spent catalyst with Na2CO3catalyst is Atmospheric residue desulphurization (ARDS) & Ebulating bed spent catalysts, the solid to liquid ratio is 1: 1 and final pH of the leached slurry is 9.6- 9.8.

[0025] In some embodiments the catalyst is Nickel & Molybdenum bearing spent Catalyst (NM), Cobalt-Nickel-Molybdenum bearing Spent Catalyst (CNM), Cobalt and Molybdenum bearing spent catalyst from Oil refineries (COMOX), the solid to liquid ratio is 1:2.2 and final pH of the leached slurry is 9.4-9.9.

[0026] In some embodiments the catalyst is the Tungsten-Nickel spent catalyst, the solid to liquid ratio is 1:2.2 and final pH of the leached slurry is 9.8-10.

[0027] In some embodiments the catalyst is ARDS & Ebulating bed spent catalysts and wherein the leaching is done at room temperature

[0028] In some embodiments the catalyst is NM, CNM, COMOX, and wherein the leaching is done at a temperature ranging from 150oC to 200oC and at a pressure of 10-20 kg / cm2

[0029] In some embodiments the catalyst is the Tungsten-Nickel spent catalyst and wherein the leaching is done at a temperature ranging from 160oC to 210oC at a pressure of 12-18 kg / cm2.

[0030] In some embodiments the catalyst is ARDS & Ebulating bed spent catalysts and wherein the amount of Na2CO3is 45 %w / w.

[0031] In some embodiments the catalyst is NM, CNM, COMOX, and wherein the amount of NaOH / Na2CO3is 10 / 28% w / w of roasted spent catalyst.

[0032] In some embodiments the catalyst is the Tungsten-Nickel spent catalyst and wherein the amount of NaOH / Na2CO3is 10 / 33 %w / w.

[0033] In some embodiments the step of precipitation comprises contacting the metallic component with a precipitant in presence of a solvent at a temperature ranging from 10-70oC to for a time period ranging from 2-6 hrs to at a pH ranging from 6 to 8.

[0034] In some embodiments the precipitant is selected from MgCl2, CaCl2, NH4Cl, NH4OH or mixtures thereof.

[0035] In some embodiments the metal compound is Ammonium Metavanadate (AMV), and wherein the step of precipitation comprises a) Adjusting pH of the filtered out liquid to 8 pH to precipitate gamma Aluminium Hydroxide and Phosphorous, which is separated by filter. b) By contacting the metallic component in the liquid with NH4Cl in presence of water at a temperature ranging from 50- 70oC for a time period ranging from 2.5-3.5 hrs at a pH ranging from 7.5-8.5.

[0036] In some embodiments the metal compound is Calcium Molybdate and wherein the step of precipitation comprises: contacting the metallic component with MgCl2, CaCl2, NH4Cl, NH4OH in presence of water at a temperature ranging from 60-80oC for a time period ranging from 2.5-3.5 hrs at a pH ranging from 5.5-8.

[0037] In some embodiments the metal compound is Calcium Tungstate and wherein the step of precipitation comprises contacting the metallic component with MgCl2, CaCl2, NH4Cl in presence of water at a temperature ranging from 30 - 45oC for a time period ranging from 2.5-3.5 at a pH ranging from 7-8.

[0038] In some embodiments the pyrometallurgy is performed in electric arc furnace.

[0039] In some embodiments different grades of synthetic Slag are produced from the Alpha alumina with varying temperature.

[0040] In some embodiments, the residual Nickel is reduced by Aluminium at 1350 to 1580℃ to form Ferro Nickel alloy with 1.5 to 15% Phosphorous.

[0041] In some embodiments, the residual Molybdenum is reduced by Aluminium at 1350 to 1580℃ to form Ferro Nickel Molybdenum alloy with 1.5 to 15% Phosphorous.

[0042] In some embodiments, the Nickel and Molybdenum bearing ferro alloys then subjected to purification at 1440 to 1470 ℃ to remove Phosphorous to make a final product – Ferro nickel and Ferro Nickel Molybdenum with less than 0.02% Phos and 0.,04% Sulphur Ni% varies from 60-75% and Molybdenum % 2 for ARDS / Ebulating bed catalysts and 15 to 20% for NIM, CNM.

[0043] In some embodiments the Gamma Alumina residue with 5 to 20% Phosphorous is melted in Arc furnace at 1380’C in presence of Carbon and Millscale to produce FerroPhosphorous for steel industry application and Calcium Aluminate Synthetic Slag and Refractory Cement

[0044] Various objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like features. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawing(s) are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. The diagrams are for illustration only, which thus is not a limitation of the present disclosure.

[0046] FIG. 1 illustrates an exemplary schematic flow diagram of a process for the ZERO waste technology for spent Vanadium / Molybdenum / Nickel / Cobalt / Tungsten catalyst recycling by Hydro Metallurgy Pyrometallurgy combination according to embodiments disclosed herein.

[0047] FIG. 2A-2C illustrates the flow diagram of the process with Mass Balance of various catalysts.

[0048] FIG. 3 depicts different grades of Calcium Aluminate synthetic Slag produced from the Alpha alumina of the residues. DETAILED DESCRIPTION OF THE INVENTION

[0049] The following is a detailed description of embodiments of the disclosure. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.

[0050] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

[0051] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with theembodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0052] In some embodiments, numbers have been used for quantifying weights, percentages, ratios, and so forth, to describe and claim certain embodiments of the invention and are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable.

[0053] The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0054] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.

[0055] Unless the context requires otherwise, throughout the specification which follows, the word “comprise” and variations thereof, such as “comprises” and “comprising” are to be construed in an open, inclusive sense that is as “including, but not limited to.”

[0056] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.

[0057] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein.

[0058] All methods described herein can be performed in a suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0059] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and / or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified.

[0060] The description that follows, and the embodiments described therein, is provided by way of illustration of an example, or examples, of particular embodiments of the principles and aspects of the present disclosure. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the disclosure.

[0061] It should also be appreciated that the present disclosure can be implemented in numerous ways, including as a system, a method or a device. In this specification, these implementations, or any other form that the invention may take, may be referred to as processes. In general, the order of the steps of the disclosed processes may be altered within the scope of the invention.

[0062] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.

[0063] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus, if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.

[0064] The term "or", as used herein, is generally employed in its sense including "and / or" unless the content clearly dictates otherwise.

[0065] Various terms are used herein to the extent a term used is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.

[0066] Catalysts bearing single or combination of metals embedded in alumina (Al2O3) matrix are used in refining processes of Crude Oil in Oil refineries and Petrochemical plants across the globe. At the end of their service life, they get contaminated by Coke, S and / or other heavy metals absorbed from the Crude oil and lose their efficiency and hence replaced by new catalysts. These spent catalysts contain leachable heavy metals like Nickel, Molybdenum, Cobalt, Vanadium etc. and hence they are Hazardous in nature and needs to be treated / disposed as per Basel convention norms.

[0067] The process according to the present disclosure allows environment friendly treatment of such spent catalysts to produce pure metal compounds and alloys for value added applications to replace the uses of metal compounds produced from Mined ores from mother earth

[0068] The process according to the present disclosure combines the Hydro and Pyro Metallurgy processes seamlessly is solving two key weaknesses of current technologies, which are - • By converting all solid ingredients into saleable products, this Pyro – Hydro Metallurgy combination technology abolishes the generation of Hazardous waste for disposal. • It produces pure metal compounds like Vanadium Pentoxide, Ammonium Para Tungstate, Cobalt Oxide etc. instead of impure metals alloys produced by Pyrometallurgy process, for specific applications of pure metal compounds made from Mined ore.

[0069] For example, Althabascsa oil sand rock ore in Canada contains Vanadium, which is absorbed by a Nickel and Moly containing catalysts in Ebulating bed upgraders along with Coke and Sulphur. When they lose their efficiency after a certain time period, they are taken out for disposal. Similarly the sour crude deposits of Middle East countries like Kuwait, Bahrain etc. contains Vanadium, which is removed from the oil train at ARDS reactors using similar Nickel and Molybdenum bearing catalysts.

[0070] It would be apparent to a person skilled in the art that typical analysis of these Spent Catalysts is as follows (In dry condition): Vanadium: 7 to 16% Molybdenum: 2 to 5%,Nickel: 3 to 6%, Sulphur: 8 to 12%, Carbon: 8 to 14%, Alumina: Balance It would be apparent to a person skilled in the art that typical analysis of Atmospheric residue desulphurization (ARDS) & Ebulating Bed Spent Catalyst is as follows:Nickel (Ni) 2 - 6% Vanadium (V) 3 - 18% Alumina (Al2O3) 35-65% Silica (SiO2) 0.2-3% Oil 8-20% Phosphorous (P) 0.1-1% Carbon (C) 6-14% Sulphur (S) 6-14%

[0071] In some embodiments, the process of the present disclosure i.e. a process combining both Hydro metallurgy and Pyro metallurgy, 100% of the Vanadium and Molybdenum may be extracted to produce pure metal compounds namely, Vanadium Pentoxide, which is used to make electrolyte for VRFB batteries, Ferro Vanadium for steel making and Calcium Molybdate for Stainless steel and Alloy steel manufacturing. In addition, in pyrometallurgy process, 100% of the Nickel content is extracted as Ferro Nickel and the Alumina Substrate is converted into Calcium Aluminate (Cl2Al7) for use in secondary steel refining and as refractory Cement. Thereby, all the elements of the spent catalyst is being converted into saleable products, leaving no Hazardous waste for disposal.

[0072] Certain oil refineries use Catalysts containing Tungsten and Nickel. Typical analysis is as follows: Tungsten: 9 to 16%, Nickel: 1 to 6%, Alumino Silicate: Balance It would be apparent to a person skilled in the art that typical analysis of Tungsten Nickel Spent Catalyst (WN) from oil refinery is as follows: Tungsten (W) 8-20% Nickel (Ni) 1-8% Alumina (Al2O3) 35-55%Silica (SiO2) 3-10% Phosphorous (P) 0.1-1% Carbon (C) 6-8% Sulphur (S) 4-10%

[0073] In some embodiments, the process of the present disclosure i.e. a process combining both Hydro metallurgy and Pyro metallurgy, 95% of Tungsten is extracted to produce pure Ammonium Para Tungstate (APT) or CALCIUM TUNGSTEATE and then by Pyrometallurgy process, 100% of the Nickel and 5% of residual Tungsten is extracted to produce Ferro Tungsten Nickel, an input for special grade of steel.

[0074] It would also be apparent to a person skilled in the art that there are certain type of catalysts containing Molybdenum, Cobalt and Nickel. Typical analysis is as follows: Molybdenum: 8 to 12%, Cobalt: 0.5 to 3%, Ni: 0.5 to 3%, S; 6 to 10%, C: 10-14%, Alumina: Balance. It would be apparent to a person skilled in the art that typical analysis of Nickel MolybdenumMolybdenum (Mo) 4-15% NickelMolybdenum (Mo) 4-15%Phosphorous (P) 0.2-1.5% Carbon (C) 6-12% the process of the present disclosure i.e. a processand Pyro metallurgy, the Molybdenum is first extracted through Hydrometallurgy process and then a combination alloy of Cobalt and Nickel is produced through Pyrometallurgy process. Cobalt and Nickel were then extracted from the concentrated alloy by acid dissolution, followed by Hydrometallurgy to separate Nickel and Cobalt to produce pure Nickel oxide and Cobalt Oxide, which are input for new generation batteries and their salts.

[0076] According to one aspect of the present disclosure, a process for recycling the spent catalyst is disclosed. FIG. 1 depicts the flow chart for the process according to the present disclosure. The process comprises the following steps: (a) exposing the spent catalyst to a temperature ranging from 700oC to 1500oC to obtain a roasted mix and a vapor stream; (b) subjecting the roasted mix to leaching to obtain a metallic component and a non-metallic component, said leaching being done in presence of NaOH and Na2CO3at a temperature ranging from 130oC to 300oC to and at a pressure ranging from 5 to 40 kg / cm2for a time period ranging from 30 minutes to 10 hour; (c) subjecting the metallic component to precipitation to obtain a metal compound, said metal compound comprising Ammonium Metavanadate (AMV), Calcium Molybdate, Calcium Tungstate or combinations thereof; (d) subjecting the non-metallic component to pyrometallurgic treatment to obtain a metal alloy and a synthetic slag, said treatment being done in presence of CaO and at a temperature ranging from 1200oC to 1500oC for a time period ranging from 1 hour to 8 hours.

[0077] In some embodiments, the spent catalyst is exposed to a temperature ranging from 800oC to 1500oC or 900oC to 1500oC or 900oC to 1500oC or 1000oC to 1500oC or 110oC to 1500oC 1200oC to 1500oC or 1300oC to 1500oC or 800oC to 1400oC or 1000oC to 1400oC or 1200oC to 1300oC to obtain a roasted mix and a vapor stream. In some embodiments, the spent catalyst is exposed to a temperature ranging from 1280oC to 1350oC to obtain a roasted mix and a vapor stream.

[0078] In some embodiments, leaching is being done in presence of NaOH and Na2CO3for a time period ranging from 30 minutes to 10 hour or 3 hours or 4 hours or 5 hours or 1hour to 10 hour or 3 hour to 10 hour or 5 hour to 10 hour or 3 hour to 5 hour or 6 hour to 10 hour or 4 hour to 10 hour or 1 hour to 5 hour or 2 hour to 5 hour or 3 hour to 6 hour etc.

[0079] In some embodiments, the non-metallic component is subjected to pyrometallurgic treatment to obtain a metal alloy and a synthetic slag at a temperature ranging from 1200oC to 1500oC or 1300oC to 1500oC or 1400oC to 1500oC or 1200oC to 1400oC or 1300oC to 1400oC. In some embodiments, the non-metallic component is subjected to pyrometallurgic treatment to obtain a metal alloy and a synthetic slag at a temperature ranging from 1340oC to 1380oC.

[0080] In some embodiments, the non-metallic component is subjected to pyrometallurgic treatment to obtain a metal alloy and a synthetic slag, said treatment being done in presence of CaO and at a temperature ranging from 1200oC to 1500oC for a time period ranging from 1 hour to 8 hours or 2 hours to 8 hours or 3 hours to 8 hours or 4 hours to 8 hours or 5 hours to 8 hours or 6 hours to 8 hours or 7 hours to 8 hours or 3 hours to 7 hours or 3 hours to 6 hours or 3 hours to 5 hours or 3 hours to 5 hours or 3 hours to 4 hours etc.

[0081] In some embodiments the step of leaching comprises contacting the roasted mix with NaOH and Na2CO3in presence of water for a time period ranging from 2.5-5 hrs.

[0082] In some embodiments the step of leaching comprises that the Pre-reacted mix of roasted spent catalyst and Na2CO3at 900℃ – 1200℃ is leached in water

[0083] In some embodiments the final pH of the leached slurry ranges from 9-10.

[0084] In some embodiments, in the step of leaching the solid to liquid ratio is 1:3.

[0085] In some embodiments the high temperature Pre-reacted mix of roasted spent catalyst with Na2CO3catalyst is ARDS & Ebulating bed spent catalysts, the solid to liquid ratio is 1: 1 and final pH of the leached slurry is 9.6-9.8.

[0086] In some embodiments the catalyst is NM, CNM, COMOX, the solid to liquid ratio is 1:2.2 and final pH of the leached slurry is 9.4-9.9. In some embodiments, wherein the catalyst is NM, CNM, COMOX, the final pH of the leached slurry is 9.4-9.6.

[0087] In some embodiments the catalyst is the Tungsten-Nickel spent catalyst, the solid to liquid ratio is 1:2.2 and final pH of the leached slurry is 9.8-10.

[0088] In some embodiments the catalyst is ARDS & Ebulating bed spent catalysts and wherein the leaching is done at room temperature. In some embodiments, wherein the catalyst is the ARDS & Ebulating bed spent catalysts, the leaching is done at a temperature of 15oC-25oC or 15oC-20oC or 20oC-25oC etc.

[0089] In some embodiments, wherein the catalyst is NM, CNM, COMOX, the leaching is done at a temperature ranging from 150oC to 200oC and at a pressure of 10-20 kg / cm2. Insome embodiments, wherein the catalyst is the NM, CNM, COMOX, the leaching is done at a temperature of 175oC at a pressure of 12 kg / cm2.

[0090] In some embodiments the catalyst is the Tungsten-Nickel spent catalyst and wherein the leaching is done at a temperature ranging from 160oC to 210oC at a pressure of 12-18 kg / cm2. In some embodiments, wherein the catalyst is the Tungsten-Nickel spent catalyst, the leaching is done at a temperature of 190oC at a pressure of 16 kg / cm2.

[0091] In some embodiments the catalyst is ARDS & Ebulating bed spent catalysts and wherein the amount of Na2CO3is 45 %w / w.

[0092] In some embodiments the catalyst is NM, CNM, COMOX, and wherein the amount of NaOH / Na2CO3is 10 / 28% w / w of roasted spent catalyst.

[0093] In some embodiments the catalyst is the Tungsten-Nickel spent catalyst and wherein the amount of NaOH / Na2CO3is 10 / 33 %w / w.

[0094] In some embodiments the step of precipitation comprises contacting the metallic component with a precipitant in presence of a solvent at a temperature ranging from 10-70oC to for a time period ranging from 2-6 hrs to at a pH ranging from 6 to 8.

[0095] In some embodiments the step of precipitation comprises contacting the metallic component with a precipitant in presence of a solvent at a temperature ranging from 10-70oC or 20-70oC or 30-70oC or 40-70oC or 50-70oC or 60-70oC or 65-70oC etc.

[0096] In some embodiments the step of precipitation comprises contacting the metallic component with a precipitant in presence of a solvent at a temperature ranging from 10-70oC for a time period ranging from 2-6 hrs or 3-6 hrs or 4-6 hrs or 5-6 hrs or 2-4 hrs or 2-3 hrs or 2-5 hrs etc.

[0097] In some embodiments the step of precipitation comprises contacting the metallic component with a precipitant in presence of a solvent at a temperature ranging from 10-70oC for a time period ranging from 2-6 hrs to at a pH ranging from 6 to 8 or 6.5 to 8 or 7 to 8 or 7.5 to 8 etc.

[0098] In some embodiments the precipitant is selected from MgCl2, CaCl2, NH4Cl, NH4OH or mixtures thereof. In some embodiments, the precipitant is NH4Cl. In some embodiments the precipitant is selected from a mixture of MgCl2, CaCl2, NH4Cl, and NH4OH. In some embodiments, the precipitant is selected from a mixture of MgCl2, CaCl2, and NH4Cl.

[0099] In some embodiments the metal compound is Ammonium Metavanadate (AMV), and wherein the step of precipitation comprisesa) Adjusting pH of the filtered out liquid to 8 pH to precipitate gamma Aluminium Hydroxide and Phosphorous, which is separated by filter. b) By contacting the metallic component in the liquid with NH4Cl in presence of water at a temperature ranging from 50- 70oC for a time period ranging from 2.5-3.5 hrs at a pH ranging from 7.5-8.5.

[0100] In some embodiments the metal compound is Calcium Molybdate and wherein the step of precipitation comprises: contacting the metallic component with MgCl2, CaCl2, NH4Cl, NH4OH in presence of water at a temperature ranging from 60-80oC for a time period ranging from 2.5-3.5 hrs at a pH ranging from 5.5-8.

[0101] In some embodiments the metal compound is Calcium Tungstate and wherein the step of precipitation comprises contacting the metallic component with MgCl2, CaCl2, NH4Cl in presence of water at a temperature ranging from 30 - 45oC for a time period ranging from 2.5-3.5 at a pH ranging from 7-8.

[0102] In some embodiments the pyrometallurgy is performed in electric arc furnace.

[0103] In some embodiments different grades of synthetic Slag are produced from the Alpha alumina with varying temperature.

[0104] In some embodiments, the residual Nickel is reduced by Aluminium at 1350 to 1580℃ to form Ferro Nickel alloy with 1.5 to 15% Phosphorous.

[0105] In some embodiments, the residual Molybdenum is reduced by Aluminium at 1350 to 1580℃ to form Ferro Nickel Molybdenum alloy with 1.5 to 15% Phosphorous.

[0106] In some embodiments, the Nickel and Molybdenum bearing ferro alloys then subjected to purification at 1440 to 1470 ℃ to remove Phosphorous to make a final product – Ferro nickel and Ferro Nickel Molybdenum with less than 0.02% Phos and 0.,04% Sulphur Ni% varies from 60-75% and Molybdenum % 2 for ARDS / Ebulating bed catalysts and 15 to 20% for NIM, CNM.

[0107] In some embodiments the Gamma Alumina residue with 5 to 20% Phosphorous is melted in Arc furnace at 1380℃ in presence of Carbon and Millscale to produce Ferro Phosphorous for steel industry application and Calcium Aluminate Synthetic Slag. Examples

[0108] The following examples are given to illustrate the present invention and do not limit the scope of the invention.

[0109] Experiment 1 was done to convert all or most of the Gamma aluminapresent in Spent catalyst to Alpha alumina (Non-reactive to alkali) while roasting to remove Sulphur and Carbon from spent catalyst. The experiment was done at 6 different temperatures 650℃,750℃, 900℃, 1000℃, 1200℃ and 1400℃. Based on analysis data of Caustic reactivity, the nominal temp for roasting was chosen to be 1280-1350℃.

[0110] Experiment 2 was carried out for various parameters for leaching to achieve maximum extraction of Molybdenum, Vanadium and Tungsten. Various parameters were optimized: i) Temperature and pressure of leaching. ii) Ratio of Caustic soda and Soda ash. iii) Time duration of leaching. iv) Final pH of leached slurry. v) Solid to liquid ratio. vi) Oxidation requirement. vii) Gpl (Gram per Litre of leach liquid) viii) Extraction %age of W, V and Mo After several experiments in laboratory followed by plant trials, the following parameters were found optimalGravimetric test procedure was adopted to ascertain quality andchemistry of each step and product. For final typical product analysis, ICP analysis was done.

[0111] FIG. 2A-2C illustrates the flow diagrams of the process of the presnt disclosure with Mass Balance.

[0112] Experiment 3 was carried out in laboratory followed by plant trials on following parameters for efficient and selective precipitation of metal compounds like Ammonium Metavanadate, Calcium Molybdate and Calcium Tungstate and removal of Phosphorous and Sulphur from the finished product. Following parameters were tested:i) Chemical to be added ii) Temperature. iii) Mixing / reaction time iv) pH v) Recovery vi) Purity. After several trials, the following parameters were found optimalTYPICAL PRODUCT ANALYSIS

[0113] Experiment 4 was done to extract residual metals from the Alpha alumina bearing using pyrometallurgy in electric arc furnace. The following parameters were studied: i) Lime addition quantity and quality for optimal synthetic slag (Calcium Aluminate)composition with lowest viscosity and melting point. ii) Temperature of melting. iii) Selection of reductant and quantity (Experiments done with Carbon, Silicon and Aluminium) iv) Recovery of Nickel and Cobalt v) Final Ferro metal chemistry vi) Double slag practice optimisation to control S and Phos level in final products as per steel industry norm. vii) Optimal current density and transformer rating. After several trials an accurate GAHLENITE phase of Calcium Aluminate of melting point between 1340℃ to 1380℃ with different Calcined lime percentage addition based on the SiO2and Al2O3content of the residue was reached. FIG. 3 explains the same in a Rankin’s ternary diagram. Different composition of Calcium Aluminate phases to cater to individual customer need and uses were established. Metallic alloy of Fe, Ni and Mo with traces of Vanadium were made with following typical chemistry of the metal ingots (Spectro analysis).Howevdual metals after hydrometallurgy process posted a problem for use as an input to Stainless steel and Alloy steel users. A 2nd slag making process was developed after the reduction melting to address the same and the typical final product chemistry is now as follows (Spectro results). FeNiMo after double slag processExperiments were carried out for dissolution of the metals in different strengths of HNO3& HCl mixture for optimal dissolution of Ni, Co, Fe and small part of Moly by repeated treatment at different temperatures. It was found that batch process of 500 ltr HCl with 30-60 ltr HNO3were ideal at 90-95℃ temperature with steam and air injection in the bath. The leached liquid laden with NiCl2, CoCl2, FeCl2and small quantity of dissolved Molybdic acid were then taken for series of experiments to remove Fe at by oxidation by aeration and Hydrogen peroxide / KMnO4at 3.5 pH. Removal of 98.5% of iron and 100% of Molybdic acid from the solution as ppt of iron- molybdenum cake was achieved. This cake was filtered out with multiple washings to make it Ni and Cobalt free. The liquid then was added with HCl to adjust pH to 2 – 2.2 and subjected to Sodium Hypo Sulphate addition to raise pH. Black Cobalt oxide precipitated out by releasing Chlorine gas which was absorbed in Ammoniacal solution to produce NH4Cl. The remaining blue coloursolution (Nickel chloride) was then taken to pH 11 by NaOH addition to get Ni(OH)2and roasted at 450℃ to produce Nickel oxide (NiO) as the finished product.

[0114] The iron cake was washed with NaOH solution to take out Molybdic acid as sodium molybdate from Iron cake, which is then converted to Calcium Molybdate as described in step 3 above. ADVANTAGES OF THE INVENTION

[0115] The proposed invention provides a newly developed technology and process which combines Hydro metallurgy and Pyro metallurgy.

[0116] The proposed invention provides a process for 100% extraction of the Vanadium and Molybdenum to produce pure metal compounds namely, Vanadium Pentoxide, which is used to make electrolyte for VRFB batteries, Ferro Vanadium for steel making and Calcium Molybdate for Stainless steel and Alloy steel manufacturing.

[0117] The proposed invention provides a process wherein all the elements of the spent catalyst is converted into saleable products, leaving no Hazardous waste for disposal.

[0118] The proposed invention provides a process which solves the issue of safe environment friendly disposal of the spent catalysts after their life cycle, which are Hazardous wastes as per Basel Convention,

[0119] The proposed invention provides a secondary source of valuable & noble metals like Vanadium, Molybdenum, Nickel, Cobalt, Tungsten etc. to reduce polluting mining activities of these otherwise scarce metals in mother earth.

[0120] Although the present invention has been described with reference to preferred embodiments, it is submitted that various modifications can be made to the exemplary embodiments without departing from the spirit and scope of the invention.

Claims

AMENDED CLAIMS received by the International Bureau on November 18, 2024 (18.11.2024)We Claim:

1. A process for recycling spent catalyst comprising the steps of:(a) subjecting the spent catalyst to a temperature ranging from 700°C to 1500°C to obtain a roasted mix and a vapor stream;(b) subjecting the roasted mix to leaching to obtain a metallic component and a nonmetallic slurry component, said leaching performed in the presence of NaOH and Na2CO3at a temperature ranging from 130°C to 300°C to and at a pressure ranging from 5 to 40 kg / cm for a time period ranging from 30 minutes to 10 hours;(c) subjecting the metallic component to precipitation to obtain a metal compound, said metal compound comprising Ammonium Metavanadate (AMV), Calcium Molybdate, Calcium Tungstate or combinations thereof, wherein the step of precipitation comprises contacting the metallic component with a precipitant; and(d) subjecting the non-metallic component to pyrometallurgic treatment in an Electric Arc furnace to obtain a metal alloy and a Calcium Aluminate compound for use as Refractory Cement and synthetic slag, said treatment being done in presence of CaO and at a temperature ranging from 1200°C to 1500°C for a time period ranging from 1 hour to 8 hours.

2. The process as claimed in claim 1, wherein the spent catalyst is exposed to a temperature ranging from 1280-1350°C to obtain a roasted mix and a vapor stream.

3. The process as claimed in claim 1, wherein the step of leaching comprises contacting the roasted mix with NaOH and Na2CO3in presence of water for a time period ranging from 2.5- 5 hrs.

4. The process as claimed in claim 1, wherein the step of leaching comprises that the Prereacted mix of roasted spent catalyst and Na2CO3at 900°C - 1200°C is leached in water5. The process as claimed in claim 1, wherein the final pH of the leached slurry ranges from 9-10.

6. The process as claimed in claim 1, wherein in the step of leaching the solid to liquid ratio is 1: 3.

257. The process as claimed in claim 1, wherein the high temperature Pre-reacted mix of roasted spent catalyst with Na2CO3 catalyst is Atmospheric residue desulphurization(ARDS) and Ebulating bed spent catalysts, the solid to liquid ratio is 1: 1 and final pH of the leached slurry is 9.6-9.8.

8. The process as claimed in claim 1, wherein the catalyst is Nickel and Molybdenum bearing spent Catalyst (NM), Cobalt-Nickel-Molybdenum bearing Spent Catalyst (CNM), Cobalt and Molybdenum bearing spent catalyst from Oil refineries (COMOX), the solid to liquid ratio is 1:2.2 and final pH of the leached slurry is 9.4- 9.9.

9. The process as claimed in claim 1, wherein the spent catalyst is the Tungsten-Nickel spent catalyst, the solid to liquid ratio is 1:2.2 and final pH of the leached slurry is 9.8-10.

10. The process as claimed in claim 1, wherein the spent catalyst is ARDS and Ebulating bed spent catalysts and wherein the leaching is done at room temperature11. The process as claimed in claim 1, wherein the spent catalyst is NM, CNM, COMOX, and wherein the leaching is done at a temperature ranging from 150°C to 200°C and at a pressure of 10-20 kg / cm212. The process as claimed in claim 1, wherein the spent catalyst is the Tungsten-Nickel spent catalyst and wherein the leaching is done at a temperature ranging from 160°C to 210°C at a pressure of 12-18 kg / cm2.

13. The process as claimed in claim 1, wherein the spent catalyst is ARDS and ebulating bed spent catalysts and wherein the amount of Na2CO3is 45% w / w.

14. The process as claimed in claim 1, wherein the spent catalyst is NM, CNM, COMOX, and wherein the amount of NaOH / Na2CO3is 10% / 28% w / w of roasted spent catalyst.

15. The process as claimed in claim 1, wherein the spent catalyst is the Tungsten-Nickel spent catalyst and wherein the amount of NaOH / Na2CO3is 10% / 33% w / w of roasted spent catalyst.

16. The process as claimed in claim 1, wherein the step of precipitation comprises contacting the metallic component with the precipitant in presence of the solvent at a temperature ranging from 10-70°C for a time period ranging from 2-6 hrs at a pH ranging from 6 to 8.

17. The process as claimed in claim 16, wherein the precipitant is selected from MgCl2, CaCl2, NH4CI, NH4OH or mixtures thereof.

18. The process as claimed in claim 1, wherein the metal compound is Ammonium Metavanadate (AMV), and wherein the step of precipitation comprises: a) adjusting pH of the filtered-out liquid to 8 pH to precipitate gamma aluminium hydroxide and phosphorous, which is separated by filter;b) by contacting the metallic component in the liquid with NH4Cl in presence of water at a temperature ranging from 50- 70°C for a time period ranging from 2.5-3.5 hrs at a pH ranging from 7.5 -8.5.

19. The process as claimed in claim 1, wherein the metal compound is Calcium Molybdate and wherein the step of precipitation comprises: contacting the metallic component with MgCl2, CaCl2, NH4Cl, NH4OH in presence of water at a temperature ranging from 60-80°C for a time period ranging from 2.5-3.5 hrs at a pH ranging from 5.5-8.

20. The process as claimed in claim 1, wherein the metal compound is Calcium Tungstate and wherein the step of precipitation comprises contacting the metallic component with MgCl2, CaCl2, NH4Cl in presence of water at a temperature ranging from 30 - 45°C for a time period ranging from 2.5-3.5 at a pH ranging from 7-8.

21. The process as claimed in claim 1, wherein different grades of synthetic Slag and Refractory Cement are produced from the Alpha alumina with varying temperature.

22. The process as claimed in claim 1, wherein the residual Nickel is reduced by Aluminium at 1350 to 1580°C to form Ferro Nickel alloy with 1.5 to 15% Phosphorous.

23. The process as claimed in claim 1, wherein the residual Molybdenum is reduced by Aluminium at 1350 to 1580°C to form Ferro Nickel Molybdenum alloy with 1.5 to 15% Phosphorous.

24. The process as claimed in claims 22 or 23, wherein the Ferro Nickel and Ferro Nickel Molybdenum alloys are subjected to purification at 1440 to 1470°C to remove Phosphorous to make a final product - Ferro Nickel and Ferro Nickel Molybdenum with less than 0.02% Phos and 0.04% Sulphur, Ni% varies from 60-75% and Molybdenum % 2 for ARDS / Ebulating bed catalysts and 15 to 20% for NIM, CNM.

25. The process as claimed in claim 1, wherein the Gamma Alumina residue with 5 to 20% Phosphorous is melted in Arc furnace at 1380°C in presence of Carbon and Millscale to produce Ferro Phosphorous for steel industry application and Calcium Aluminate Cement and Synthetic Slag.

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