Method for recycling palladium from tetra(triphenylphosphine) palladium waste liquid

Abstract

The invention discloses a method for recycling palladium from tetra(triphenylphosphine) palladium waste liquid. The method comprises the following steps: (1), adding 10% by volume of ethanol into a certain amount of tetra(triphenylphosphine) palladium waste liquid, heating to 120 DEG C, concentrating for one hour, cooling to room temperature to generate a small amount of floccule precipitate, then filtering, collecting solids and retaining filtrate; (2), adding a certain amount of oxidizing agent into the filtrate, then adding a complexing reagent to generate a small amount of floccules, filtering, and discharging the filtrate; and (3) combining the previously collected solids, and then roasting, reducing and refining to obtain high-purity palladium powder. The method is simple in operation condition, low in equipment requirement, mild in reaction condition, excellent in safety and high in recovery rate; the palladium content in the treated waste liquid is less than 5ppm; and the waste liquid can be discharged. According to the method for recycling palladium from tetra(triphenylphosphine) palladium waste liquid, the recovery rate of the palladium powder is greater than 99.5%, and the purity of the palladium powder is higher than 99.95%; and the method is obvious in economic and environmental protection benefits.

Description

technical field [0001] The invention belongs to the field of chemistry and chemical engineering, and in particular relates to a method for recovering palladium from tetrakis(triphenylphosphine)palladium waste liquid. Background technique [0002] There are a lot of information about recovering high-purity palladium from palladium-containing waste liquid, but the methods proposed by most of the materials are applicable to the inorganic phase aqueous solution system containing palladium. The commonly used classic method is aqua regia or nitric acid dissolution-dichlorodiamine palladium purification - The process of reducing hydrazine hydrate, such as the literature "Precious Metals" Vol.38, No.S1 and the literature "Guangdong Chemical Industry" 2020, 47(20), 25-26. However, there are few reports on the method of recovering palladium from the palladium-containing organic waste liquid, especially about the recovery of palladium in the tetrakis(triphenylphosphine) palladium waste...

AI Technical Summary

Problems solved by technology

[0004] (1) Use benzene as a solvent, but benzene is a highly flammable liquid at room temperature, has high toxicity, and is also a carcinogen, which is not conducive to industrial production

[0005] (2) use dimethyl sulfoxide instead of benzene as a solvent, which can avoid the poisoning of people, but the tetrakis (triphenylphosphine) palladium waste liquid (mainly dimethyl sulfoxide) produced in the production contains a relatively low amount of palladium, and the recovery Among them, palladium is more difficult

[0007] (1) Chinese patent CN102159737A "A method for extracting precious metals by adsorption" adopts the method for adsorbing precious metals by adsorbents, which is used for precious metals in different types of minerals, and does not solve the problem of tetrakis (triphenylphosphine) palladium waste liquid containing organic matter Adsorption of palladium in

[0008] (2) There are also functional adsorbents developed by many manufacturers on the market, such as the Chinese patent CN110368905A "A Mercaptoamine Functionalized Silica Gel Material and Its Application", which discloses precious metals used for adsorbing waste liquids (inorganic or organic) , but at present there is no disclosed adsorbent and method with good adsorption effect and industrialized recovery of precious metals; Chinese patent CN102560140B "A Method for Recovering Palladium from Organic Waste Liquid" discloses a method for analyzing and reducing after using a solid phase extractant, The process is cumbersome, the operation is complicated, and it cannot be industrialized; Chinese patent CN103555957A "A Method for Recovering High-purity Metal Palladium from a Catalyst Containing Organic Waste Palladium" discloses the recovery of high-purity metal palladium from a catalyst containing organic waste palladium. The method of palladium, the way to deal with organic matter is to refine palladium powder after incineration, and the boiling point of dimethyl sulfoxide in tetrakis (triphenylphosphine) palladium waste liquid is 189 ° C and has good thermal stability. After high temperature incineration, it decomposes and has a foul smell Odors such as methyl mercaptan and dimethyl sulfide will cause nausea and vomiting symptoms, and the incineration discharge will cause extreme environmental pollution, metals will be volatilized and lost, and the palladium content in the waste liquid is low, which is not conducive to recycling in terms of cost. Therefore do not possess suitability for industrialized production; CN108642300A " a kind of method of recovering palladium from containing palladium waste catalyst " discloses and adopts complex solution to elute waste palladium catalyst and then hydrazine hydrate reduction, and this method extracts incomplete tetrakis (triphenylphosphine ) palladium of palladium waste liquid

[0009] (3) In the document "Precious Metals" 2015,36(01), 17-20, it is reported that rhodium is reclaimed from spent organic catalysts by using the alloy method, that is, the solid-state reduced iron capture method, and palladium can also be reclaimed by this method, but for four (three) Phenylphosphine) palladium waste liquid is not easy to achieve in dimethyl sulfoxide in pellet drying, which will produce unpleasant and toxic waste gas, causing serious environmental pollution. The palladium content in the waste liquid is low and the waste liquid is more, and it is not worth it in terms of cost. ; In the document "Precious Metals" Vol.39, No.S1, it is reported that nitric acid is used to dissolve tetrakis (triphenylphosphine) palladium, and perchloric acid fumes to decompose organic matter, and the content of palladium is determined by complexometric titration

The method of this article is to detect the metal content in the sample tetrakistriphenylphosphine palladium, using highly corrosive nitric acid and perchloric acid, using this method for mass production, the operation is difficult, the requirements for equipment are extremely high, and the operator is easy A safety accident occurs, so this method can not be carried out in industrialized production; Zhejiang University of Technology master's thesis "from tetrakis (triphenylphosphine) palladium production waste liquid in the method exploration of recovering palladium " has studied zinc reduction method, chemical precipitation method and electrolytic method. The combination of deposition method, adsorption method and direct electrodeposition method to recover palladium in tetrakis(triphenylphosphine) palladium waste liquid requires fine operation. As the amount of waste liquid increases, the treatment becomes more difficult and the effect is worse, so it cannot be popularized. From industrial production, all methods in this paper still have too low recovery rate and high cost for expensive palladium