Method for recycling palladium in waste liquid through tannin biological adsorption

Abstract

The invention discloses a method for separating and recovering palladium in palladium-containing waste liquid, and aims to solve the problem of low recovery rate of the palladium-containing waste liquid. According to the technical scheme, the method is characterized by comprising the following steps: (1) filtering first palladium-containing waste liquid to obtain filtrate, adsorbing the filtrate through ion exchange resin, and desorbing the adsorbed ion exchange resin to form second palladium-containing waste liquid, the concentration of palladium in the second palladium-containing waste liquid is greater than the concentration of palladium in the first palladium-containing waste liquid. According to the method, the heavy metal palladium is adsorbed by adopting a tannin biological method before palladium recovery, so that the content of palladium in the palladium-containing waste liquid can be reduced to 0.1 mg / l or below, other noble metals except palladium are removed as much as possible, the purification rate of palladium is greatly improved, organic matters attached to the surface of palladium are removed by adopting a washing method in the palladium recovery process, and compared with a traditional roasting method, the method has the advantages that the cost is reduced, and the recovery efficiency is improved. Energy consumption is low, and industrial operation is facilitated.

Description

[0001] This application is a divisional application of a patent application entitled "A method for separating and recovering palladium from palladium-containing waste liquid". The application date of the original application is August 3, 2022, and the application number is CN202210924891.4. Technical Field

[0002] The invention relates to the technical field of palladium recovery, and more specifically to a method for separating and recovering palladium from palladium-containing waste liquid. Background Art

[0003] The main source of palladium-containing waste liquid is the activation and passivation electroplating waste liquid in the process production of various electronic industries. The waste liquid is weakly acidic and has a palladium content of ~50ppm. The waste liquid produced by precious metals such as palladium and gold contains ~10ppm of palladium. The waste water from the cleaning of workpieces after the metallization of printed circuit board holes, plastic electroplating and various non-metallic electroplating activation also contains a certain amount of palladium, with a content of ~1ppm. Studies have found that a large amount of palladium-containing waste liquid in the electroplating industry is discharged as ordinary wastewater, which not only increases the difficulty of subsequent wastewater treatment, but also causes a waste of resources. According to statistics, about 3 tons of metal palladium in the palladium-containing waste liquid generated by my country's electroplating and circuit board industries each year cannot be effectively recovered. In addition, the discharge and accumulation of palladium in the environment will endanger human health, such as causing diseases such as asthma, allergies and rhinitis. In order to improve the recovery rate of palladium in printed circuit board waste liquid, domestic and foreign researchers have successively conducted different degrees of research on extraction, ion exchange and resin adsorption. Although these studies have made some progress in some aspects, they also have certain shortcomings. The better treatment technology can only reduce the palladium content to 3-4ppm. The different forms of palladium in palladium-containing wastewater are one of the important reasons for the reduction of palladium recovery rate.

[0004] Therefore, a solution needs to be proposed to solve this problem. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for separating and recovering palladium from palladium-containing waste liquid. Before recovering the palladium, the present invention uses a tannin biological method to adsorb heavy metal palladium, which can reduce the palladium content in the palladium-containing waste liquid to within 0.1 mg / l, so that the remaining precious metals except palladium are removed as much as possible, greatly improving the palladium purification rate, and in the palladium recovery process, a washing method is used to remove organic matter attached to the surface of the palladium. Compared with the traditional roasting method, the method has low energy consumption and is convenient for industrial operation.

[0006] The above technical objective of the present invention is achieved by the following technical scheme: A method for separating and recovering palladium from palladium-containing waste liquid, comprising the following steps: Step (1): filtering a first palladium-containing waste liquid to obtain a filtrate, adsorbing the filtrate through an ion exchange resin, and desorbing the adsorbed ion exchange resin to form a second palladium-containing waste liquid, wherein the concentration of palladium in the second palladium-containing waste liquid is greater than the concentration of palladium in the first palladium-containing waste liquid;

[0007] Step (2): adding an alcohol or ketone reagent to the first palladium-containing waste liquid and the second palladium-containing waste liquid in step (1), heating to 70-140° C., concentrating, then cooling to room temperature, filtering, collecting solid A, and retaining filtrate A;

[0008] Step (3): adding a certain amount of oxidant to the filtrate A, and then adding a complexing agent to generate a small amount of floccules, filtering, collecting solid B, and discharging the waste liquid;

[0009] Step (4): combining the previously collected solid A and solid B, and then roasting, reducing and refining them to obtain high-purity palladium powder.

[0010] The present invention is further configured as follows: in step (1), the adsorption treatment time is 3-5 minutes.

[0011] The present invention is further configured as follows: in step (1), the ion exchange resin is a chelating resin.

[0012] The present invention is further configured as follows: after the waste liquid discharged in step (3) is filtered, ammonia water can be added to precipitate the remaining metal elements and collect them.

[0013] The present invention is further configured as follows: the step (1) also includes: detecting the heavy metal palladium content in the filtrate, when the heavy metal palladium content in the first filtrate is detected to be ≤0.1 mg / l, washing the filter residue with pure water to obtain a tannin adsorption material adsorbed with heavy metal palladium and with impurities removed; when the heavy metal palladium content in the filtrate is detected to be >0.1 mg / l, repeatedly adding the tannin adsorption material to the acidic palladium-containing waste liquid, stirring evenly and letting it stand, and then filtering to obtain a filter residue and a filtrate, until the heavy metal palladium content in the filtrate is >0.1 mg / l, and then starting the washing step.

[0014] The present invention is further configured as follows: in the step (1), an important component of the tannin adsorption material is tannin phenolic resin.

[0015] In summary, the present invention has the following beneficial effects:

[0016] The present invention uses a tannin biological method to adsorb heavy metal palladium before recovering palladium, which can reduce the palladium content in the palladium-containing waste liquid to within 0.1 mg / l, so that the remaining precious metals except palladium are removed as much as possible, greatly improving the palladium purification rate, and a washing method is used to remove organic matter attached to the surface of palladium in the palladium recovery process. Compared with the traditional roasting method, the present invention has low energy consumption and is convenient for industrial operation. Moreover, the entire palladium recovery process is simple, the palladium recovery rate can be as high as 99.9%, and the contents of the remaining metal elements contained in the tail liquid can be controlled, energy saving and emission reduction, green environmental protection, reduced production costs, and improved enterprise economic benefits. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with specific embodiments. It should be noted that the embodiments of the present application and the features therein may be combined with each other without conflict.

[0018] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "set / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] The present invention is described in detail below.

[0020] Embodiment 1: A method for separating and recovering palladium from palladium-containing waste liquid, comprising the following steps: Step (1): filtering a first palladium-containing waste liquid to obtain a filtrate, adsorbing the filtrate through an ion exchange resin, and desorbing the adsorbed ion exchange resin to form a second palladium-containing waste liquid, wherein the concentration of palladium in the second palladium-containing waste liquid is greater than the concentration of palladium in the first palladium-containing waste liquid;

[0021] Step (2): adding an alcohol or ketone reagent to the first palladium-containing waste liquid and the second palladium-containing waste liquid in step (1), heating to 70° C., concentrating, then cooling to room temperature, filtering, collecting solid A, and retaining filtrate A;

[0022] Step (3): adding a certain amount of oxidant to the filtrate A, and then adding a complexing agent to generate a small amount of floccules, filtering, collecting solid B, and discharging the waste liquid;

[0023] Step (4): combining the previously collected solid A and solid B, and then roasting, reducing and refining to obtain high-purity palladium powder.

[0024] In step (1), the adsorption treatment time is 3-5 minutes.

[0025] In step (1), the ion exchange resin is a chelating resin.

[0026] After filtering the waste liquid discharged in step (3), ammonia water may be added to precipitate the remaining metal elements for collection.

[0027] Step (1) also includes: detecting the heavy metal palladium content in the filtrate, and when the heavy metal palladium content in the first filtrate is detected to be ≤0.1 mg / l, washing the filter residue with pure water to obtain a tannin adsorption material adsorbed with heavy metal palladium and with impurities removed; when the heavy metal palladium content in the filtrate is detected to be greater than 0.1 mg / l, repeatedly adding the tannin adsorption material to the acidic palladium-containing waste liquid, stirring evenly and letting it stand, and then filtering to obtain a filter residue and a filtrate, until the heavy metal palladium content in the filtrate is greater than 0.1 mg / l, and then starting the washing step.

[0028] In step (1), an important component of the tannin adsorption material is tannin phenolic resin.

[0029] Embodiment 2: A method for separating and recovering palladium from palladium-containing waste liquid, comprising the following steps: Step (1): filtering a first palladium-containing waste liquid to obtain a filtrate, adsorbing the filtrate through an ion exchange resin, and desorbing the adsorbed ion exchange resin to form a second palladium-containing waste liquid, wherein the concentration of palladium in the second palladium-containing waste liquid is greater than the concentration of palladium in the first palladium-containing waste liquid;

[0030] Step (2): adding an alcohol or ketone reagent to the first palladium-containing waste liquid and the second palladium-containing waste liquid in step (1), heating to 100° C., concentrating, then cooling to room temperature, filtering, collecting solid A, and retaining filtrate A;

[0031] Step (3): adding a certain amount of oxidant to the filtrate A, and then adding a complexing agent to generate a small amount of floccules, filtering, collecting solid B, and discharging the waste liquid;

[0032] Step (4): combining the previously collected solid A and solid B, and then roasting, reducing and refining to obtain high-purity palladium powder.

[0033] In step (1), the adsorption treatment time is 3-5 minutes.

[0034] In step (1), the ion exchange resin is a chelating resin.

[0035] After filtering the waste liquid discharged in step (3), ammonia water may be added to precipitate the remaining metal elements for collection.

[0036] Step (1) also includes: detecting the heavy metal palladium content in the filtrate, and when the heavy metal palladium content in the first filtrate is detected to be ≤0.1 mg / l, washing the filter residue with pure water to obtain a tannin adsorption material adsorbed with heavy metal palladium and with impurities removed; when the heavy metal palladium content in the filtrate is detected to be greater than 0.1 mg / l, repeatedly adding the tannin adsorption material to the acidic palladium-containing waste liquid, stirring evenly and letting it stand, and then filtering to obtain a filter residue and a filtrate, until the heavy metal palladium content in the filtrate is greater than 0.1 mg / l, and then starting the washing step.

[0037] In step (1), an important component of the tannin adsorption material is tannin phenolic resin.

[0038] Embodiment 3: A method for separating and recovering palladium from palladium-containing waste liquid, comprising the following steps: Step (1): filtering a first palladium-containing waste liquid to obtain a filtrate, adsorbing the filtrate through an ion exchange resin, and desorbing the adsorbed ion exchange resin to form a second palladium-containing waste liquid, wherein the concentration of palladium in the second palladium-containing waste liquid is greater than the concentration of palladium in the first palladium-containing waste liquid;

[0039] Step (2): adding an alcohol or ketone reagent to the first palladium-containing waste liquid and the second palladium-containing waste liquid in step (1), heating to 140° C., concentrating, then cooling to room temperature, filtering, collecting solid A, and retaining filtrate A;

[0040] Step (3): adding a certain amount of oxidant to the filtrate A, and then adding a complexing agent to generate a small amount of floccules, filtering, collecting solid B, and discharging the waste liquid;

[0041] Step (4): combining the previously collected solid A and solid B, and then roasting, reducing and refining to obtain high-purity palladium powder.

[0042] In step (1), the adsorption treatment time is 3-5 minutes.

[0043] In step (1), the ion exchange resin is a chelating resin.

[0044] After filtering the waste liquid discharged in step (3), ammonia water may be added to precipitate the remaining metal elements for collection.

[0045] Step (1) also includes: detecting the heavy metal palladium content in the filtrate, and when the heavy metal palladium content in the first filtrate is detected to be ≤0.1 mg / l, washing the filter residue with pure water to obtain a tannin adsorption material adsorbed with heavy metal palladium and with impurities removed; when the heavy metal palladium content in the filtrate is detected to be greater than 0.1 mg / l, repeatedly adding the tannin adsorption material to the acidic palladium-containing waste liquid, stirring evenly and letting it stand, and then filtering to obtain a filter residue and a filtrate, until the heavy metal palladium content in the filtrate is greater than 0.1 mg / l, and then starting the washing step.

[0046] In step (1), an important component of the tannin adsorption material is tannin phenolic resin.

[0047] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for separating and recovering palladium from palladium-containing waste liquid, comprising the following steps: Step (1): filtering the first palladium-containing waste liquid to obtain a filtrate, adsorbing the filtrate with a chelating resin, and desorbing the adsorbed ion exchange resin to form a second palladium-containing waste liquid; Step (2): adding an alcohol or ketone reagent to the first palladium-containing waste liquid and the second palladium-containing waste liquid in step (1), heating to 70-140° C., concentrating, then cooling to room temperature, filtering, collecting solid A, and retaining filtrate A; Step (3): adding a certain amount of oxidant to the filtrate A, and then adding a complexing agent to generate a small amount of floccules, filtering, collecting solid B, and discharging the waste liquid; Step (4): combining the previously collected solid A and solid B, and then roasting, reducing and refining them to obtain high-purity palladium powder.

2. A method for separating and recovering palladium in a palladium-containing waste liquid according to claim 1, characterized in that: After filtering the waste liquid discharged in step (3), ammonia water may be added to precipitate the remaining metal elements for collection.

3. A method for separating and recovering palladium in a palladium-containing waste liquid according to claim 1, characterized in that: The step (1) further comprises: detecting the heavy metal palladium content in the filtrate; when the heavy metal palladium content in the first filtrate is detected to be ≤0.1 mg / l, washing the filter residue with pure water to obtain a tannin phenolic resin adsorbed with heavy metal palladium and with impurities removed; when the heavy metal palladium content in the filtrate is detected to be >0.1 mg / l, repeatedly adding the tannin phenolic resin to the acidic palladium-containing waste liquid, stirring evenly and letting it stand, and then filtering to obtain a filter residue and a filtrate, until the heavy metal palladium content in the filtrate is >0.1 mg / l, and then starting the washing step.