Method for recovering palladium in waste colloid palladium activating solution

Abstract

The invention relates to a method for recovering palladium in a waste colloid palladium activation solution, in particular to the technical field of secondary utilization of resources, the recovery method comprises the following steps: adding a gel breaker into the waste colloid palladium activation solution, and then carrying out solid-liquid separation to obtain recovered palladium; wherein the gel breaker comprises one or a combination of at least two of an epichlorohydrin-dimethylamine copolymer, dimethyl diallyl ammonium chloride or a dimethyl diallyl ammonium chloride copolymer. According to the recovery method provided by the invention, the original dispersion stability of colloidal palladium is destroyed by adopting the specific gel breaker, the dispersed atomic state palladium particles are aggregated into large particles, and effective separation of palladium can be realized through solid-liquid separation.

Description

Technical Field

[0001] The invention relates to the technical field of secondary utilization of resources, and in particular to a method for recovering palladium from waste colloidal palladium activation solution. Background Art

[0002] At present, palladium activation is a necessary process in the non-metallic electroplating process. There are two ways to activate palladium on the surface of non-metallic materials: colloidal palladium activation and ionic palladium activation. Since colloidal palladium activation has more stable performance and simpler process, it is widely used in PCB electroplating and hardware electroplating processes.

[0003] For example, CN104328393A discloses a process for activating a printed circuit board in salt-based colloidal palladium, which comprises the following steps:

[0004] 1) Immerse the roughened printed circuit board in a solution of 10 g / L stannous oxide, 10 mL / L oxalic acid, and 200 g / L sodium oxide;

[0005] 2) Place the printed circuit board in a tank containing a salt-based colloidal palladium solution and shake the printed circuit board continuously in the tank;

[0006] 3) Wash the printed circuit board with water.

[0007] During use, the performance of the colloidal palladium activation liquid gradually decreases and needs to be replenished or replaced, thereby generating waste colloidal palladium liquid.

[0008] The main components of the waste palladium colloidal liquid are palladium (metal palladium with zero valence), stannous chloride, hydrochloric acid, stannous ion stabilizer and trace amounts of tetravalent tin. Palladium exists in the solution as atomic particles, and stannous ions gather on the surface of palladium particles to form micelles, thus forming a stable dispersion system. Since palladium resources are precious, it is of great significance to recover the metal palladium in the waste colloidal palladium activation solution.

[0009] For example, CN113481373A discloses a method for separating and recovering palladium from an activation solution, comprising the following steps: pretreatment and activation of polyamide resin; pretreatment of colloidal palladium activation solution; adsorption of palladium by colloidal palladium activation solution; depalladiuming of polyamide resin; purification of palladium-containing solution; and reduction of high-purity sponge palladium.

[0010] For example, CN113481373A discloses a method for separating and recovering palladium from an activation solution, comprising the following steps: pretreatment and activation of polyamide resin; pretreatment of colloidal palladium activation solution; adsorption of palladium by colloidal palladium activation solution; depalladiuming of polyamide resin; purification of palladium-containing solution; and reduction of high-purity sponge palladium.

[0011] In the above scheme, microwave heating is used to break the colloidal palladium waste liquid, and oxidation can also be used to break the gel. However, heat and the addition of oxidants will promote the oxidation of stannous ions to tetravalent tin, and further form insoluble β-stannic acid. After breaking the gel, β-stannic acid will be mixed with palladium particles and co-precipitated, requiring subsequent complex purification treatment.

[0012] Based on this, CN108060306A discloses a palladium recovery method for enriching palladium-containing wastewater by adsorption, wherein palladium is adsorbed from palladium-containing wastewater by a zinc wire device; palladium chloride powder is obtained from the zinc wire device adsorbed with palladium; the palladium chloride powder is dissolved in water, and then ammonia water is added and stirred until a yellow third solution is obtained; and a hydrazine hydrate solution is titrated into the third solution, stirred, precipitated, and filtered to obtain a black powder. Since the content of colloidal palladium in the waste liquid is as low as 30-200ppm, and the concentration of HCl is high, when metallic magnesium or zinc contacts the colloidal waste liquid, a violent side reaction occurs, resulting in a very large amount of metallic magnesium or zinc, which is not conducive to the recovery of palladium.

[0013] In summary, the existing palladium recovery methods still have the problems of poor palladium recovery effect, low palladium recovery rate and complicated subsequent purification process. Summary of the invention

[0014] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for recovering palladium in waste colloidal palladium activation solution to solve the problems of poor palladium recovery effect, low palladium recovery rate and complicated subsequent purification process in the existing palladium recovery method.

[0015] To achieve this object, the present invention adopts the following technical solutions:

[0016] The present invention provides a method for recovering palladium in a waste colloidal palladium activation solution, the method comprising:

[0017] Adding a debonding agent to the waste colloidal palladium activation solution, and then recovering palladium through solid-liquid separation;

[0018] The debonding agent comprises: one or a combination of at least two of epichlorohydrin dimethylamine copolymer, dimethyldiallyl ammonium chloride or dimethyldiallyl ammonium chloride copolymer.

[0019] The recovery method provided by the present invention uses a specific decolloiding agent to destroy the original dispersion stability of colloidal palladium, and aggregates dispersed atomic palladium particles into large particles, and effectively separates palladium through solid-liquid separation.

[0020] As a preferred technical solution of the present invention, the mass ratio of the breaker to the waste colloidal palladium activation solution is (1-100):1.

[0021] Preferably, the mass concentration of the breaker is 5-10%.

[0022] As a preferred technical solution of the present invention, the degumming agent used includes epichlorohydrin dimethylamine copolymer and dimethyl diallyl ammonium chloride in a mass ratio of 1: (0.2-0.5).

[0023] As a preferred technical solution of the present invention, stirring is performed during the addition of the degumming agent.

[0024] As a preferred technical solution of the present invention, the stirring speed is 100-300r / min.

[0025] As a preferred technical solution of the present invention, if particles appear during the addition of the degumming agent, stirring is stopped.

[0026] Preferably, the breaker is added before stopping stirring.

[0027] As a preferred technical solution of the present invention, the solid-liquid separation method includes: one of filtration, suction filtration, filter pressing or centrifugal separation.

[0028] As a preferred technical solution of the present invention, the recovered palladium is sequentially acid-washed, cleaned and dried to obtain palladium powder with a purity of more than 98%.

[0029] As a preferred technical solution of the present invention, the acid used for pickling includes concentrated hydrochloric acid.

[0030] As a preferred technical solution of the present invention, the cleaning method includes water washing and / or alcohol washing.

[0031] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0032] The present invention provides a recovery method, which destroys the dispersion stability of colloidal palladium with the help of a specific decolloiding agent and promotes the aggregation of palladium particles into large particles, thereby achieving separation of metallic palladium, and then simply acid washing and tin removal to achieve recovery of palladium with a purity of more than 98%, and the recovery rate of palladium in the process is ≥97.8%. DETAILED DESCRIPTION

[0033] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0034] This embodiment provides a method for recovering palladium from a waste colloidal palladium activation solution, the method comprising:

[0035] Adding a debonding agent to the waste colloidal palladium activation solution, and then recovering palladium through solid-liquid separation;

[0036] The debonding agent comprises: one or a combination of at least two of epichlorohydrin dimethylamine copolymer, dimethyldiallyl ammonium chloride or dimethyldiallyl ammonium chloride copolymer.

[0037] Exemplarily, the main components of the waste colloidal palladium activation solution targeted by the present invention are as follows:

[0038] Palladium 30-200ppm, stannous chloride 30-50g / L, HCl 2-4mol / L, stannic acid 1-5g / L.

[0039] In the present invention, the molecular weight of the epichlorohydrin dimethylamine copolymer used is 10,000-30,000.

[0040] In the present invention, the molecular weight of the dimethyldiallylammonium chloride copolymer used is 10,000-20,000.

[0041] Wherein, the mass ratio of the breaker to the waste colloidal palladium activation solution is (1-100):1 in mg / g, for example, it can be 1:1, 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, 55:1, 60:1, 65:1, 70:1, 75:1, 80:1, 85:1, 90:1, 95:1 or 100:1, etc., but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0042] Among them, the mass concentration of the breaker is 5-10%, for example, it can be 5%, 5.5%, 6%, 6.5%, 7.%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%, etc., but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0043] Furthermore, the debonding agent used in the present invention is preferably a copolymer of epichlorohydrin dimethylamine and dimethyl diallyl ammonium chloride in a mass ratio of 1:(0.2-0.5).

[0044] Wherein, the gel breaker is added with stirring.

[0045] In the present invention, the process of adding the breaker can be optionally supplemented with ultrasound, vibration or aeration to enhance the dispersion effect of the breaker.

[0046] Wherein, the stirring speed is 100-300r / min, for example, it can be 100r / min, 120r / min, 140r / min, 160r / min, 180r / min, 200r / min, 220r / min, 240r / min, 260r / min, 280r / min or 300r / min, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0047] If particles appear during the addition of the degumming agent, stirring is stopped.

[0048] In the present invention, the waste colloidal palladium activation solution is initially a transparent uniform solution. During the process of adding a breaker, the palladium particles will agglomerate under the action of the breaker to form particles.

[0049] Wherein, the gel breaker is added before stopping stirring.

[0050] The addition method of the gel breaker includes single addition, addition in stages or continuous addition.

[0051] For example, the breaker can be added in stages, such as dividing the breaker into n portions and adding one portion every time t. The breaker can be added continuously, such as dripping, or by various conveying and feeding equipment such as a peristaltic pump.

[0052] Wherein, the solid-liquid separation method includes: one of filtration, suction filtration, filter pressing or centrifugal separation.

[0053] The recovered palladium is sequentially pickled, cleaned and dried to obtain palladium powder with a purity of more than 98%.

[0054] Wherein, the acid used for pickling includes concentrated hydrochloric acid.

[0055] Wherein, the cleaning method includes water washing and / or alcohol washing.

[0056] The drying method may be vacuum drying, freeze drying or other conventional drying methods in the art.

[0057] Further, in order to illustrate the recycling effect that can be achieved by the recycling method provided by the present invention, the following actual examples are used for exemplary description, as follows:

[0058] Example 1

[0059] This embodiment provides a method for recovering palladium in a waste colloidal palladium activation solution, the method comprising:

[0060] A debonding agent is added to the waste colloidal palladium activation solution, and then the palladium is recovered by filtration.

[0061] The main components of the waste colloidal palladium activation solution in this embodiment are as follows: palladium 100ppm, stannous chloride 40g / L, HCl 3mol / L, stannic acid 3g / L;

[0062] The breaker comprises: epichlorohydrin dimethylamine copolymer (molecular weight is 20000), the mass ratio of the breaker to the waste colloidal palladium activation liquid is 50:1 in mg / g, and the mass concentration of the breaker is 6%;

[0063] The breaker is added with stirring at a speed of 180 r / min. If particles appear during the breaker addition, stirring is stopped. The breaker is added before stirring is stopped.

[0064] The recovered palladium is sequentially pickled with concentrated hydrochloric acid, washed with water and dried to obtain palladium powder.

[0065] Example 2

[0066] This embodiment provides a method for recovering palladium in a waste colloidal palladium activation solution, the method comprising:

[0067] A debonding agent is added to the waste colloidal palladium activation solution, and then the palladium is recovered by filtration.

[0068] The main components of the waste colloidal palladium activation solution targeted in this embodiment are as follows:

[0069] Palladium 150ppm, stannous chloride 45g / L, HCl 2.5mol / L, stannic acid 4g / L;

[0070] The breaker comprises: a dimethyldiallyl ammonium chloride copolymer (molecular weight 15000), the mass ratio of the breaker to the waste colloidal palladium activation solution is 10:1 in mg / g, and the mass concentration of the breaker is 8%;

[0071] The breaker is added with stirring at a speed of 240 r / min. If particles appear during the breaker addition, stirring is stopped. The breaker is added before stirring is stopped.

[0072] The recovered palladium is sequentially pickled with concentrated hydrochloric acid, washed with water and dried to obtain palladium powder.

[0073] Example 3

[0074] This embodiment provides a method for recovering palladium in a waste colloidal palladium activation solution, the method comprising:

[0075] A debonding agent is added to the waste colloidal palladium activation solution, and then the palladium is recovered by suction filtration.

[0076] The main components of the waste colloidal palladium activation solution targeted in this embodiment are as follows:

[0077] Palladium 30ppm, stannous chloride 30g / L, HCl 2mol / L, stannic acid 1g / L;

[0078] The breaker comprises: epichlorohydrin dimethylamine copolymer (molecular weight is 10000), the mass ratio of the breaker to the waste colloidal palladium activation solution is 1:1, and the mass concentration of the breaker is 10%;

[0079] The breaker is added with stirring at a speed of 200 r / min. If particles appear during the breaker addition, stirring is stopped. The breaker is added before stirring is stopped.

[0080] The recovered palladium is sequentially pickled with concentrated hydrochloric acid, washed with water and dried to obtain palladium powder.

[0081] Example 4

[0082] This embodiment provides a method for recovering palladium in a waste colloidal palladium activation solution, the method comprising:

[0083] A debonding agent is added to the waste colloidal palladium activation solution, and then the palladium is recovered by filter pressing.

[0084] The main components of the waste colloidal palladium activation solution targeted in this embodiment are as follows:

[0085] Palladium 200ppm, stannous chloride 50g / L, HCl 4mol / L, stannic acid 5g / L;

[0086] The breaker comprises: dimethyldiallylammonium chloride, the mass ratio of the breaker to the waste colloidal palladium activation liquid is 100:1 in mg / g, and the mass concentration of the breaker is 5%;

[0087] The breaker is added with stirring at a speed of 150 r / min. If particles appear during the breaker addition, stirring is stopped. The breaker is added before stirring is stopped.

[0088] The recovered palladium is sequentially pickled with concentrated hydrochloric acid, washed with water and dried to obtain palladium powder.

[0089] Example 5

[0090] The only difference from Example 1 is that the mass ratio of the breaker to the waste colloidal palladium activation solution is 0.5:1 in mg / g.

[0091] Example 6

[0092] The only difference from Example 1 is that the mass ratio of the breaker to the waste colloidal palladium activation solution is 150:1 in mg / g.

[0093] Example 7

[0094] The only difference from Example 1 is that the mass concentration of the breaker is 1%.

[0095] Example 8

[0096] The only difference from Example 1 is that the mass concentration of the breaker is 15%.

[0097] Example 9

[0098] The only difference from Example 1 is that no stirring is performed during the addition of the breaker.

[0099] Example 10

[0100] The only difference from Example 1 is that the breaker used is an equal amount of epichlorohydrin dimethylamine copolymer and dimethyldiallylammonium chloride in a mass ratio of 1:0.3.

[0101] Embodiment 11

[0102] The only difference from Example 2 is that the breaker used is an equal amount of epichlorohydrin dimethylamine copolymer and dimethyldiallylammonium chloride in a mass ratio of 1:0.4.

[0103] Example 12

[0104] The only difference from Example 3 is that the breaker used is an equal amount of epichlorohydrin dimethylamine copolymer and dimethyldiallylammonium chloride in a mass ratio of 1:0.2.

[0105] Embodiment 13

[0106] The only difference from Example 4 is that the breaker used is an equal amount of epichlorohydrin dimethylamine copolymer and dimethyldiallylammonium chloride in a mass ratio of 1:0.5.

[0107] Embodiment 14

[0108] The only difference from Example 10 is that the breaker used is an equal amount of epichlorohydrin dimethylamine copolymer and dimethyldiallylammonium chloride in a mass ratio of 0.3:1.

[0109] Embodiment 15

[0110] The only difference from Example 10 is that the breaker used is an equal amount of epichlorohydrin dimethylamine copolymer and dimethyldiallylammonium chloride in a mass ratio of 1:2.

[0111] Example 16

[0112] The only difference from Example 10 is that the breaker used is an equal amount of epichlorohydrin dimethylamine copolymer and dimethyldiallylammonium chloride in a mass ratio of 1:0.1.

[0113] Embodiment 17

[0114] The only difference from Example 1 is that the breaker used is an equal amount of epichlorohydrin dimethylamine copolymer and dimethyldiallyl ammonium chloride copolymer in a mass ratio of 1:0.3.

[0115] The recovery rate of palladium recovered and the purity of palladium powder obtained in the above examples are shown in Table 1 below.

[0116] Table 1

[0117]

[0118]

[0119] According to Table 1, by comparing Example 9 with Example 1, it can be determined that the stirring effect is very important in the degumming process, which can not only improve the purity of the recovered palladium powder, but also improve the recovery rate. This is mainly because the stirring effect promotes the uniform dispersion of the degumming agent and its full contact with the micelle, which promotes the full polymerization and sedimentation of the palladium particles and reduces the inclusion of the degumming agent in the palladium powder.

[0120] By comparing Examples 5-8 with Example 1, it can be seen that the greater the amount of breaker added, the less obvious the increase in recovery rate or even a decrease, and the purity of palladium powder is also reduced, which is due to the co-deposition of impurities formed by the breaker and the tin salt. Among them, according to Example 6, when the amount of breaker added is too large, the recovery rate and purity are reduced, which is because the breaker itself has a certain viscosity, and excessive addition inhibits the aggregation and sedimentation of palladium particles.

[0121] By comparing the results of Examples 10-17, it can be seen that the palladium powder purity and recovery rate of the gel breaker compounded with epichlorohydrin dimethylamine copolymer and dimethyldiallyl ammonium chloride are better than those of epichlorohydrin dimethylamine copolymer alone. The reason is that there are differences in the adsorption and viscosity of the two, which can compensate for each other after compounding, achieving stronger adsorption performance while having lower viscosity.

[0122] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0123] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0124] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for recovering palladium from waste colloidal palladium activation solution, characterized in that: The recovery method comprises: Adding a debonding agent to the waste colloidal palladium activation solution, and then recovering palladium through solid-liquid separation; The debonding agent comprises: one or a combination of at least two of epichlorohydrin dimethylamine copolymer, dimethyldiallyl ammonium chloride or dimethyldiallyl ammonium chloride copolymer.

2. The recycling method according to claim 1, characterized in that: The mass ratio of the breaker to the waste colloidal palladium activation solution is (1-100): 1; Preferably, the mass concentration of the breaker is 5-10%.

3. The recycling method according to claim 1, characterized in that: The debonding agent used comprises epichlorohydrin dimethylamine copolymer and dimethyldiallylammonium chloride in a mass ratio of 1:(0.2-0.5).

4. The recycling method according to claim 1, characterized in that: The process of adding the debonding agent is assisted with stirring.

5. The recycling method according to claim 4, characterized in that: The stirring speed is 100-300r / min.

6. The recovery method according to claim 4 or 5, characterized in that: If particles appear during the addition of the degelling agent, stirring is stopped; Preferably, the breaker is added before stopping stirring.

7. The recycling method according to claim 1, characterized in that: The solid-liquid separation method includes: one of filtration, suction filtration, filter pressing or centrifugal separation.

8. The recycling method according to claim 1, characterized in that: The recovered palladium is sequentially acid-washed, cleaned and dried to obtain palladium powder with a purity of more than 98%.

9. The recycling method according to claim 1, characterized in that: The acid used for pickling includes concentrated hydrochloric acid.

10. The recycling method according to claim 1, characterized in that: The cleaning method includes water washing and / or alcohol washing.

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