Method for recovering valuable metal from waste catalyst

Abstract

To provide a method enabling recovery of valuable metal from a waste catalyst without generation of gas such as SOx or wastewater.SOLUTION: According to one embodiment of the present invention, a valuable metal recovery method comprises a leaching step in which a first inorganic compound containing VO3 is leached from a waste catalyst at a temperature lower than 100°C and under atmospheric pressure.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for recovering valuable metals from spent catalysts.

Background Art

[0002] A catalyst is a substance that does not react by itself in any reaction system but causes activation so that the overall reaction proceeds at a high speed, and is a substance required in the treatment processes in oil refining and petrochemicals. In the treatment processes in oil refining and petrochemicals, the amount of catalyst used is small compared to the FEED used, but in fact, the amount of catalyst used is gradually increasing due to the increase in oil refining and petrochemical plants.

[0003] In particular, in oil refining and petrochemical plants, various catalysts containing valuable metals such as molybdenum, vanadium, nickel, and aluminum are used. However, each catalyst containing the valuable metal gradually deteriorates in performance over time and is replaced after its lifespan has expired. Conventionally, spent catalysts with expired lifespans have been landfilled in their entirety without any special treatment method, resulting in soil pollution problems such as groundwater contamination due to the elution of heavy metals, and there has been a problem that valuable metals with high added value that can be utilized as raw materials for advanced industries have not been recycled and have been discarded as they are.

[0004] In response to the above problems, in order to minimize soil pollution and recycle high - added - value valuable metals that rely on imports, various methods have been proposed for recovering valuable metals such as molybdenum and vanadium, which are precious metals, from spent catalysts that have expired in the oil refining and petrochemical processes.

[0005] However, especially when recovering valuable metals from desulfurization spent catalysts, in conventional processes, roasting is performed at high temperature and / or high pressure, resulting in problems such as environmental pollution due to the generation of gases such as sulfur dioxide and excessive generation of energy costs, and there has been an economic loss due to complex processes and the need for separate facilities.

[0006] In addition, due to the high-temperature and high-pressure processes, nickel and aluminum are recovered and not reused but discarded as industrial waste, causing environmental pollution and significant economic losses.

Summary of the Invention

Problems to be Solved by the Invention

[0007] One problem is to provide a method for recovering valuable metals from waste catalysts that does not generate gases such as SOx and wastewater.

[0008] One problem is to provide a method for recovering valuable metals from waste catalysts that does not require high-temperature and / or high-pressure processes for removing sulfur and the like from the waste catalysts and leaching metal compounds.

[0009] One problem is to provide a method for recovering valuable metals from waste catalysts that can recover not only vanadium but also molybdenum, aluminum, and nickel at high recovery rates.

Means for Solving the Problems

[0010] The method for recovering valuable metals according to one aspect of the present invention includes a waste catalyst preparation step of preparing a waste catalyst, and a leaching step of leaching the waste catalyst prepared in the waste catalyst preparation step with a first inorganic compound containing VO3 under conditions of a temperature of less than 100°C and normal pressure. - and leaching it as a first inorganic compound containing VO3 under conditions of a temperature of less than 100°C and normal pressure.

[0011] As one aspect, the leaching step may include a step of stirring the prepared waste catalyst in a leaching solution containing sodium hydroxide under conditions of a temperature of less than 100°C and normal pressure.

[0012] As one aspect, the leaching solution containing sodium hydroxide may be an aqueous sodium hydroxide solution with a concentration of 3% to 20%.

[0013] As one aspect, the leaching step may include a step of injecting oxygen or air.

[0014] As one aspect, it is preferable that a step of heat-treating the spent catalyst at a temperature of 100°C or higher is not included after the step of preparing the spent catalyst and before the leaching step.

[0015] As one aspect, a precipitation step may further be included in which a salt is added to the first inorganic compound leached in the leaching step to precipitate a second inorganic compound containing VO3 - is included.

[0016] As one aspect, the salt added in the precipitation step may be ammonium chloride.

[0017] As one aspect, a step may further be included in which the second inorganic compound precipitated in the precipitation step is oxidized, hydrochloric acid is added to the generated ammonia to generate ammonium chloride, and then the generated ammonium chloride is reused.

[0018] As one aspect, a vanadium oxide recovery step may further be included in which the second inorganic compound precipitated in the precipitation step is oxidized to recover vanadium oxide.

[0019] As one aspect, a step of recovering any one or more selected from the group consisting of nickel, nickel compounds, aluminum, aluminum compounds, molybdenum, and molybdenum compounds may further be included.

Advantages of the Invention

[0020] As one advantage, the method for recovering valuable metals according to one aspect of the present invention does not generate gases such as SOx and wastewater such as leaching solutions, so environmental pollution and economic costs can be significantly reduced.

[0021] As one advantage, the method for recovering valuable metals according to one aspect of the present invention does not require a high-temperature and / or high-pressure step for removing sulfur or the like from the spent catalyst or leaching metal compounds, so energy costs can be significantly reduced.

[0022] As an effect, the method for recovering valuable metals according to one aspect of the present invention can recover not only vanadium but also molybdenum, aluminum, and nickel at high recovery rates.

Brief Description of the Drawings

[0023]

Figure 1

Modes for Carrying Out the Invention

[0024] Expressions such as "including" used in this specification should be understood as open-ended terms that encompass the possibility of including other configurations.

[0025] "Preferred" and "preferably" used in this specification are used for embodiments of the present invention that have a predetermined advantage under predetermined conditions. However, such description is not intended to exclude other embodiments from the technical scope of the present invention.

[0026] The singular forms used in this specification can be intended to include plural forms as well, unless otherwise specifically indicated in the context.

[0027] In this specification, terms such as "first" and "second" are not used in a limiting sense but for the purpose of distinguishing one component from another.

[0028] The numerical ranges used in this specification include lower and upper limits, all values within that range, increments logically derived in the form and width of the defined range, all values doubly limited, and all possible combinations of the upper and lower limits of numerically defined ranges limited in different forms.

[0029] Unless otherwise specifically defined in this specification, values outside the numerical ranges that may occur due to experimental error or rounding of values are also included in the defined numerical ranges.

[0030] On the one hand, each of the technical features described later relates to one aspect for achieving the object and effects of the present invention described above. That is, the method for recovering valuable metals according to one aspect of the present invention can generate the above-described one effect by including the technical features according to one aspect described later.

[0031] The present invention relates to a method for recovering valuable metals from spent catalysts.

[0032] In the oil refining and petrochemical fields, catalysts are used to smoothly remove sulfur and the like in crude oil. Usually, since the life of the catalyst is 3 to 5 months, it is periodically replaced. At this time, spent catalysts, which are used catalysts, may be generated.

[0033] The spent catalyst may contain one or more valuable metals selected from molybdenum, cobalt, aluminum, and nickel, in addition to vanadium.

[0034] In this specification, recovering valuable metals means not only recovering the valuable metals themselves but also recovering them as marketable forms of compounds containing the valuable metals.

[0035] In the present invention, the compounds and / or valuable metals containing the valuable metals can be extracted and recovered by using a simple, economical, and environmentally friendly method.

[0036] As an example of the compound containing the valuable metal, (NH4)VO3 or vanadium pentoxide (V2O5) can be mentioned. The compound or vanadium contained therein can be used as a raw material for alloy steel, a raw material for aviation, automobiles, and electronic materials, a raw material for next-generation REDOX batteries, and the like.

[0037] As an example of the compound containing the valuable metal, molybdenum trioxide (MoO3) can be mentioned. The compound or molybdenum contained therein can be used as a raw material for special alloy steel, a raw material for the military industry or industrial machinery, and the like.

[0038] As an example of a compound containing a valuable metal, nickel oxide (NiO) can be cited. The compound or the nickel contained therein can be used as a raw material for a positive electrode material of a battery or a raw material for stainless steel heat-resistant steel.

[0039] As an example of a compound containing a valuable metal, aluminum oxide (Al2O3) or aluminum hydroxide (Al(OH)3) can be cited. The compound or the aluminum contained therein can be used as a raw material for packaging (cans, foils) and building materials.

[0040] As an example of a compound containing a valuable metal, an oxide containing cobalt can be cited. The compound or the cobalt contained therein can be used as a raw material for a positive electrode material of a secondary battery.

[0041] First, a waste catalyst preparation step of preparing the above-mentioned waste catalyst is performed.

[0042] The waste catalyst to be prepared may be a waste catalyst for desulfurization.

[0043] As one aspect, in the waste catalyst preparation step, the waste catalyst may be ground alone or ground together with an aqueous solution containing sodium hydroxide. The size of the ground waste catalyst may be 100 μm or less, and the grinder used for grinding may be any commonly used grinder such as a ball mill.

[0044] Next, the waste catalyst prepared in the waste catalyst preparation step is leached with a first inorganic compound containing VO3 under temperature conditions of less than 100 °C, 98 °C or less (or less), 95 °C or less (or less), more preferably 92 °C or less (or less), 50 °C or more (or more), 60 °C or more (or more), 70 °C or more (or more), 80 °C or more (or more), more preferably 85 °C or more (or more). - A leaching step of leaching is performed.

[0045] Also, the leaching step is performed under normal pressure conditions.

[0046] Here, the normal pressure condition refers to the pressure in a state where no pressure reduction equipment such as a vacuum pump or pressure increase equipment is used. For example, about 760 mmHg, which is a general atmospheric pressure, corresponds to this.

[0047] Since the reaction of the present invention is carried out at a temperature below the boiling point of water, the pressure in the reactor automatically becomes 1 atm or less, and there is no need for a reactor that can withstand pressure, and an inexpensive reactor made of a plastic material can be used.

[0048] As one aspect, the leaching step may include a step of stirring the prepared waste catalyst in a leaching solution containing sodium hydroxide under the conditions of a temperature below 100°C and normal pressure.

[0049] As a more specific aspect, wet smelting can be carried out while stirring the waste catalyst in a leaching solution containing sodium hydroxide, for example, an aqueous sodium hydroxide solution.

[0050] As a more preferable example, the mass ratio of the leaching solution containing sodium hydroxide added to the mass of the waste catalyst may be 1 to 40, 5 to 30, or 10 to 20.

[0051] In one aspect of the present invention, when leaching as an aqueous sodium hydroxide solution under the conditions of the temperature and pressure, sulfuric acid gas may not be discharged, or when the aqueous sodium hydroxide solution is directly recovered and reused, wastewater may not be generated.

[0052] As a more preferable example, the leaching solution containing sodium hydroxide may be an aqueous sodium hydroxide solution having a concentration of 3% or more, 4% or more, 5% or more, 20% or less, 15% or less, 10% or less, 7% or less. The present invention can recover valuable metals in a high yield under the conditions of low temperature and normal pressure by adjusting the aqueous sodium hydroxide solution to the above concentration and using this as a leaching solution.

[0053] As one aspect, the leaching step may further include a step of additionally injecting oxygen or air while leaching with a leaching solution containing sodium hydroxide under conditions of a temperature below 100 °C and normal pressure.

[0054] Vanadium in a trivalent oxidation state can be formed as an intermediate product of the leaching step. As an example, the intermediate product of the leaching step is NaVO2.

[0055] As one aspect, the VO3 leached in the leaching step - The first inorganic compound containing is sodium metavanadate (NaVO3).

[0056] Next, the leaching step may further include a filtration step of filtering the first inorganic compound containing VO3 leached in the leaching step. The filtration step is not particularly limited as long as it is a usable method. - In the filtration step, a solid phase containing nickel, aluminum, cobalt, etc. and a liquid phase in which vanadium, molybdenum, etc. are dissolved may be separated from each other.

[0057] As one aspect, in the filtration step, nickel, aluminum, cobalt, etc. in the solid solution existing as the solid phase may be extracted in a separate form.

[0058] As one aspect, in the filtration step, nickel, aluminum, cobalt, etc. in the solid solution existing as the solid phase may be extracted in a separate form.

[0059] Next, a salt is added to the first inorganic compound containing VO3 leached in the leaching step, and a precipitation step of precipitating a second inorganic compound containing VO3 may be further performed. At this time, before adding the salt, it may be preferable to add an acidic substance such as hydrochloric acid to adjust the pH of the solution to 7. - including - As an example, the salt added in the precipitation step is ammonium chloride.

[0060] As an example, the salt added in the precipitation step is ammonium chloride.

[0061] At this time, more preferably, the ammonium chloride is added in a molar amount of 2 to 4 times, or 2.5 to 3.5 times, the number of moles of vanadium leached in the leaching step.

[0062] As an example, the precipitated VO3 - The second inorganic compound containing is ammonium metavanadate ((NH4)VO3).

[0063] As an example, the precipitation step is represented by the following Reaction Formula 1.

[0064] <Reaction Formula 1> NaVO3 + NH4Cl → (NH4)VO3↓ + NaCl

[0065] In one aspect, the precipitation step may further include a filtration step of filtering the precipitated second inorganic compound. The filtration step is not particularly limited as long as it is a usable method.

[0066] Next, it may further include a step of recovering vanadium oxide by oxidizing the second inorganic compound precipitated in the precipitation step.

[0067] As an example, the vanadium oxide may be vanadium (V) oxide (V2O5). As long as the vanadium oxide can be recovered from the second inorganic compound containing the precipitated VO3 - the method is not particularly limited.

[0068] In one aspect, it is not necessary to include a step of heat-treating the waste catalyst at a temperature of 100°C or higher after the step of preparing the waste catalyst and before the leaching step.

[0069] The present invention does not require a separate pretreatment step including a process of removing and oxidizing oil or sulfur contained in the waste catalyst.

[0070] In the conventional process, a roasting process is performed to remove oil, sulfur, etc. At this time, separate equipment for the roasting process is required. However, in the present invention, since the waste catalyst is not roasted at a temperature of 100°C or higher to remove sulfur, etc. after the waste catalyst preparation step and before the leaching step, separate equipment is not required, and there is almost no gas emission such as SOx, which is environmentally friendly.

[0071] Also, as described above, the present invention leaches the first inorganic compound containing VO3 under the conditions of a temperature of less than 100°C and normal pressure, so the leaching step does not include a step of heat-treating the waste catalyst at a temperature of 100°C or higher. - Therefore, the leaching step does not include a step of heat-treating the waste catalyst at a temperature of 100°C or higher.

[0072] As a more specific aspect, after the waste catalyst preparation step and before the leaching step, or in the leaching step, it is not necessary to include a step of heat-treating the waste catalyst at 100°C or higher, 200°C or higher, 300°C or higher, 400°C or higher, 500°C or higher, 600°C or higher, 700°C or higher, or 800°C or higher.

[0073] As a more preferred aspect, after oxidizing the second inorganic compound precipitated in the above-mentioned precipitation step and adding hydrochloric acid to the generated ammonia to generate ammonium chloride, the step of recycling the generated ammonium chloride may be further included.

[0074] As one aspect, the present invention may further include a step of recovering any one or more selected from nickel, nickel compounds, aluminum, aluminum compounds, molybdenum, and molybdenum compounds.

[0075] The step of recovering the nickel compound and / or nickel may be performed through a separate separation step after the leaching step of leaching the first inorganic compound containing VO3, which can be performed by a known method. As an example, nickel or a nickel compound can be extracted from the Ni / Al2O3 residue formed in the leaching step. - This can be carried out by a known method. For example, nickel or a nickel compound can be extracted from the Ni / Al2O3 residue formed in the leaching step.

[0076] The step of recovering the molybdenum compound and / or molybdenum may be carried out after a separate separation step following the leaching step of leaching the first inorganic compound containing the VO3 - and this can be carried out by a known method.

[0077] In a more preferred embodiment, after the precipitation step of precipitating the second inorganic compound containing the VO3 - a step of adding a molybdic acid (H2MoO4) reagent in a molar amount 3 to 7 times, or 4 to 6 times, the molar amount of molybdenum to the extraction solution from which vanadium has been recovered may be carried out.

[0078] Next, after adding the molybdic acid (H2MoO4) reagent, the temperature is raised to 70°C to 90°C, and molybdenum can be recovered by adjusting the pH to 2.5 to 3.5 while adding an acid.

[0079] The step of recovering the aluminum compound and / or aluminum may be carried out after a separate separation step following the leaching step of leaching the first inorganic compound containing the VO3 - and this can be carried out by a known method.

[0080] The present invention can recover nickel and / or aluminum without performing a step of roasting the waste catalyst and without performing the leaching step under conditions of a temperature of less than 100°C and normal pressure.

[0081] Hereinafter, the embodiments of the present invention will be described more specifically.

Examples

[0082] Leaching step of vanadium / molybdenum

[0083] 30 g of a pellet-type desulfurization waste catalyst containing the components shown in Table 1 below generated by an oil refining company in Korea was pulverized using a ball mill.

[0084] [Table 1]

[0085] The crushed raw material was placed in a 1 L glass reactor, and 360 g of a 6% sodium hydroxide (NaOH) solution was added. The mixture was stirred at 250 rpm, the temperature of the reactor was raised to 90°C, and air was supplied to the leaching solution at a rate of 300 cc / min using a gas bubbler to extract the metals.

[0086] The metal content in the extraction solution was analyzed using ICP (inductively coupled plasma), and the extraction rates of vanadium and molybdenum were calculated using the following calculation formula 1.

[0087] JPEG2025110619000003.jpg19170

[0088] Table 2 below shows the analytical results of the extraction rate of each metal depending on the reaction time.

[0089] [Table 2]

[0090] Vanadium precipitation and recovery process

[0091] 200 g of the extract solution containing vanadium and molybdenum was placed in a 500 ml reactor and stirred at 200 rpm at room temperature. 5% hydrochloric acid was added to adjust the pH of the solution to 7.

[0092] Ammonium chloride (NH4Cl) powder was added to the pH-adjusted solution so that vanadium would precipitate as ammonium vanadate (NH4VO3). The amount of ammonium chloride powder added was three times the moles of vanadium contained in the solution.

[0093] The recovery rate of vanadium to ammonium vanadate (NH4VO3) was calculated using the following calculation formula 2.

[0094] JPEG2025110619000005.jpg18170

[0095] The following Table 3 shows the analysis results of the recovery rate of vanadium according to the reaction time after adding ammonium chloride.

[0096]

Table 3

[0097] Precipitation and recovery process of molybdenum

[0098] After recovering vanadium in the above vanadium precipitation process and putting 200 g of the remaining extraction solution into a 500 ml glass reactor, while stirring at 200 rpm, a molybdic acid (H2MoO4) reagent 5 times (5 equivalents) to the content (number of moles) of molybdenum in the extraction solution was added.

[0099] The temperature of the extraction solution was raised to 80 °C, and 5% hydrochloric acid was added until the pH of the solution reached 3. After the pH of the solution reached 3, the extraction solution was analyzed over time, and the recovery rate of molybdenum was calculated in the same method as the calculation formula for the recovery rate of the above vanadium.

[0100] The following Table 4 shows the analysis results of the recovery rate of molybdenum according to the reaction time.

[0101]

Table 4

Claims

1. A method for recovering valuable metals, which includes a leaching step of leaching a first inorganic compound containing VO from a spent catalyst under conditions of a temperature of less than 100 °C and normal pressure. ３ － ​

2. The leaching step includes a step of stirring the waste catalyst in a leaching solution containing sodium hydroxide under conditions of a temperature of less than 100°C and normal pressure. The method for recovering valuable metals according to Claim 1.

3. The leaching solution containing sodium hydroxide is an aqueous sodium hydroxide solution with a concentration of 3% to 20%. The method for recovering valuable metals according to Claim 2.

4. The leaching step includes a step of injecting oxygen or air. The method for recovering valuable metals according to Claim 1.

5. Before the leaching step, the method for recovering valuable metals according to Claim 1 does not include a step of heat-treating the waste catalyst at a temperature of 100°C or higher.

6. After the leaching step, a salt is added to the first inorganic compound leached in the leaching step to precipitate a second inorganic compound containing VO ３ － The method for recovering a valuable metal according to claim 1, further comprising a precipitation step of precipitating.

7. The salt added in the precipitation step is ammonium chloride. The method for recovering valuable metals according to Claim 6.

8. The method for recovering valuable metals according to Claim 6 further includes a step of oxidizing the second inorganic compound precipitated in the precipitation step, adding hydrochloric acid to the formed ammonia to produce ammonium chloride, and then recycling the produced ammonium chloride.

9. After the precipitation step, the method for recovering valuable metals according to Claim 6 further includes a step of oxidizing the second inorganic compound precipitated in the precipitation step to recover vanadium oxide, a vanadium oxide recovery step.

10. After the precipitation step, the method for recovering valuable metals according to Claim 6 further includes a step of recovering any one or more selected from nickel, nickel compounds, aluminum, aluminum compounds, molybdenum, and molybdenum compounds.

Images