CN-121976049-A - Precious metal leaching agent for recycling waste catalyst and application thereof

Abstract

The invention relates to the technical field of precious metal recovery and catalytic material regeneration, and discloses a precious metal leaching agent for waste catalyst recovery and application thereof. The noble metal leaching agent comprises an organic acid and an organic nitrile. And (3) roasting the waste catalyst, hot-leaching in the noble metal leaching agent, and performing solid-liquid separation, wherein the obtained filtrate is used for enriching noble metals, and meanwhile, the waste catalyst carrier is obtained. The invention constructs a noble metal leaching mode driven by the cooperation of the organic acid and the organic nitrile, overcomes the corrosion risk of the traditional strong oxidation leaching system on the carrier, realizes the unification of high-efficiency recovery of the noble metal and reutilization of the carrier, and has good industrial application prospect.

Inventors

• FENG YONGJUN
• WANG QIHUI
• TANG PINGGUI
• ZHANG QIANYUAN
• LI CHUNLI
• AI YONGHONG
• CHEN YOUSHENG
• WU LEILIN

Assignees

• 北京化工大学
• 江西五矿高安有色金属有限公司

Dates

Publication Date

20260505

Application Date

20251229

Claims (10)

1. 1. A precious metal leaching agent for spent catalyst recovery, characterized in that the precious metal leaching agent comprises an organic acid and an organic nitrile.
2. 2. The precious metal leaching agent according to claim 1, wherein the organic acid is selected from at least one of formic acid, acetic acid, oxalic acid, citric acid, tartaric acid and succinic acid, preferably from at least one of formic acid, acetic acid, oxalic acid and citric acid; preferably, in the precious metal leaching agent, the concentration of the organic acid is 1-65g/L, preferably 10-30g/L.
3. 3. The precious metal leaching agent according to claim 1 or 2, wherein the organic nitrile is selected from at least one of acetonitrile, propionitrile, isobutyronitrile, pyruvonitrile and butyronitrile, preferably from at least one of acetonitrile, propionitrile and isobutyronitrile; preferably, the organic nitrile is present as an organic nitrile-water mixed system; preferably, the volume fraction of the organic nitrile in the organic nitrile-water mixed system is 20-90%, preferably 80%.
4. 4. Use of a precious metal leaching agent according to any one of claims 1-3 in spent catalyst recovery.
5. 5. The use according to claim 4, wherein the noble metal in the spent catalyst is palladium and/or silver.
6. 6. A method for recovering a spent catalyst using the noble metal leaching agent of any one of claims 1 to 3, comprising calcining the spent catalyst, hot leaching in the noble metal leaching agent, and performing solid-liquid separation, wherein the obtained filtrate is used for enriching noble metals, and simultaneously obtaining a spent catalyst carrier.
7. 7. The method of claim 6, wherein the firing procedure includes firing at a rate of 1-20 ℃ per minute at a temperature of 300-800 ℃ for 1-4 hours; preferably, the rate of temperature rise is 5-10 ℃ per minute; preferably, the firing temperature is 500-700 ℃; preferably, the roasting time is 2-3 hours.
8. 8. The process according to claim 6 or 7, wherein the liquid-to-solid ratio of calcined spent catalyst to precious metal leaching agent is 1-50mL/g, preferably 1-20mL/g.
9. 9. A method according to any one of claims 6 to 8, wherein the temperature of the hydrothermal leach is 100-150 ℃, preferably 120 ℃; Preferably, the time of the hydrothermal leaching is 1-5 hours, preferably 1 hour.
10. 10. The method according to any one of claims 6 to 9, wherein the filtrate obtained from the solid-liquid separation is adsorbed by a resin to enrich the noble metal.

Description

Precious metal leaching agent for recycling waste catalyst and application thereof Technical Field The invention relates to the technical field of precious metal recovery and catalytic material regeneration, in particular to a precious metal leaching agent for waste catalyst recovery and application thereof. Background The noble metals include eight elements, gold (Au), silver (Ag), and platinum group metals (platinum (Pt), palladium (Pd), rhodium (Rh)), ruthenium (Ru), osmium (Os), and iridium (Ir)). These elements are relatively scarce compared to common nonferrous metals to obtain "noble metal" labels. Although gold and silver have important economic properties from ancient times as money metals, with the development of modern industrial systems, noble metals play an irreplaceable role in the fields of electronic information, chemical catalysis, energy sources, optics, medical treatment and the like due to their unique chemical inertness, catalytic performance, conductivity and thermal stability. In particular, in the fine chemical industry and the hydrogenation catalysis industry, noble metals such as Pd, ag, pt and the like are widely loaded on porous carriers with high added value such as alumina, silicon dioxide and the like, and are used for various selective hydrogenation and oxidation reactions. Currently, the conventional metallurgical technology has difficulty in meeting the requirement of noble metal supply, and secondary resources such as waste electronic devices, waste catalysts and industrial residues containing noble metals gradually become main alternative sources of noble metal supply due to high metal content and rich sources, but the recovery of the secondary resources still faces great technical difficulties. In the waste catalyst, noble metals are usually firmly attached to the surface of a porous oxide carrier in a metal simple substance state, an alloy state or a highly dispersed state, and the interface of the noble metals and the carrier has strong bonding, high surface inertia and strong oxidation resistance and coordination resistance, so that conventional leaches (such as inorganic acid, alkali and complexing agent) cannot effectively dissolve the noble metals. For example, both Pd and Ag have a high standard electrode potential and stable metal bonds, which are difficult to release from the support unless a specific complex is formed or subjected to an oxidation-coordination-dissolution process. Therefore, how to leach noble metals efficiently while maintaining the carrier structure constitutes a core technical challenge in the field of noble metal hydrometallurgy. The existing noble metal hydrometallurgy technology mainly utilizes the oxidizing property of a strong oxidizing agent, and adopts H 2O2, hypochlorite, perchlorate and other strong oxidizing agents to oxidize and dissolve noble metal Pd/Ag, but the method is usually accompanied with the problems of serious carrier corrosion, high environmental risk, poor metal selectivity and the like. CN117089713a discloses a method for recovering platinum from a platinum/alumina spent catalyst and a platinum leaching system. According to the method, pt/gamma-Al 2O3 is roasted to remove carbon deposition, gamma-Al 2O3 is converted into alpha-Al 2O3 through second-stage roasting, then Pt is dissolved out by taking a solution consisting of NaCl, naHSO 4、H2O2 and water as a leaching solution, and the Pt leaching solution is converted into sponge platinum after a series of treatments. This technique reduces reagent consumption while rapidly dissolving platinum, but its carrier is completely dissolved. CN119464710A is prepared by roasting and reducing the waste catalyst, and then using a solution consisting of potassium hydrogen peroxymonosulfate/H 2O2 and acetonitrile/propionitrile as a leaching solution, and reacting for 4 hours at 60 ℃ to dissolve Pd and Ag. The technology can effectively leach noble metals and retain the carrier structure of the noble metals by generating active free radicals through a strong oxidant and a nitrile solution. However, this technique has a problem that the reaction time is long and the retention rate of the pore structure of the carrier is only 90.8%. In the prior art, oxalic acid is often used as a reducing agent or a weak complexing agent for leaching or surface treatment of transition metals (such as Fe, cu, ni and the like). For example, patent CN106011472a adopts oxalic acid solution with reducibility, and the pentavalent vanadium in the waste SCR denitration catalyst is reduced to tetravalent vanadium by adjusting the pH value of the solution to 1-1.5, keeping the temperature of the solution to 90-100 ℃ in a water bath and stirring for 3 hours, and then concentrating and crystallizing. However, when oxalic acid is applied to a noble metal leaching system, the inventors found that when only the waste catalyst containing palladium-silver is treated with oxalic acid under the same temperature and hy