Waste lead dioxide anode resource recycling method

Abstract

The invention provides a waste lead dioxide anode resource recycling method which comprises the following steps: pretreatment: cleaning a waste lead dioxide anode to remove electrolyte crystals on the surface; the pretreated waste anode is placed in a hydrochloric acid solution to react for 30-50 min, and surface metal oxide is removed; the waste anode is placed in a solution B and soaked for 20-40 min at the normal temperature, part of lead dioxide is dissolved, and the solution B comprises 13-18 wt% of nitric acid and 13-18 wt% of hydrogen peroxide; adding nitric acid and hydrogen peroxide to enable the mixed solution to contain 23-27wt% of nitric acid and 23-27wt% of hydrogen peroxide, heating the mixed solution to 50-60 DEG C, continuously reacting for 25-40 minutes under the condition of blowing air, and dissolving the residual lead dioxide to obtain a leaching solution; the leaching liquid is repeatedly used until the concentration of lead nitrate in the leaching liquid reaches 250-320 g / L, and the leaching liquid is conveyed to an electroplating production line to be recycled after being filtered; and the treated titanium base material is cleaned and then is electroplated again for use. The waste lead dioxide anode resource recycling method provided by the invention is a low-temperature, high-efficiency and low-pollution regeneration technology, and can realize the repeated use of a titanium substrate and the recycling of a lead nitrate solution.

Description

Technical Field

[0001] The present invention relates to the technical field of resource recovery, and particularly to a method for recycling waste lead dioxide anodes. Background Art

[0002] Waste lead dioxide anodes mainly come from lead-acid batteries, electroplating tanks, and hydrometallurgical processes. The lead paste covering their surfaces mainly consists of lead dioxide (PbO2), and also contains impurities such as sulfates (e.g., nickel sulfate, cobalt sulfate) and metal oxides (e.g., calcium oxide, magnesium oxide).

[0003] Traditional methods for recovering lead dioxide include pyrometallurgy, electrolytic reduction, and wet acid leaching. Among them, pyrometallurgy requires a high temperature above 1200°C, with high energy consumption (>500 kWh / ton), and produces lead vapor and sulfides during the recovery process, resulting in serious pollution; the electrolytic reduction method relies on a high-energy-consuming DC power supply (>200 A / m 2 ), with a lead recovery rate of only 80%-85%, and the electrolyte is easily contaminated by impurities; the wet acid leaching process uses nitric acid for leaching, requires a high concentration of acid (>30%), has a long reaction time (>2 hours), and a high cost for treating waste liquid (>100 yuan / ton).

[0004] In view of this, it is necessary to provide a new recovery method to solve the above technical problems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for recycling waste lead dioxide anodes, which is a low-temperature, high-efficiency, and low-pollution regeneration technology, and can realize the reuse of titanium substrates and the recycling of lead nitrate solutions.

[0006] The technical solution of the present invention is as follows:

[0007] A method for recycling waste lead dioxide anodes includes the following steps:

[0008] Step S1, pretreatment: cleaning the waste lead dioxide anode to remove the electrolyte crystals on the surface;

[0009] Step S2, preparing solution A, placing the pretreated waste anode in solution A, reacting for 30-50 min to remove the metal oxides on the surface; wherein solution A includes 10-12 wt% hydrochloric acid and 0.2-0.5 wt% surfactant;

[0010] Specifically, the concentration of hydrochloric acid can be 10 wt%, 11 wt%, or 12 wt%, or other values within this range; the concentration of the surfactant can be 0.2 wt%, 0.3 wt%, 0.4 wt%, or 0.5 wt%, or other values within this range;

[0011] Step S3: Prepare solution B. Place the waste anode with the surface metal oxide removed into solution B and soak it at room temperature for 20 - 40 minutes to dissolve part of the lead dioxide.

[0012] Solution B includes 13 - 18 wt% nitric acid and 13 - 18 wt% hydrogen peroxide. For example, the concentration of nitric acid can be 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt% or 18 wt%, or other values within this range; the concentration of hydrogen peroxide can be 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt% or 18 wt%, or other values within this range.

[0013] Step S4: Supplement nitric acid and hydrogen peroxide to make the mixed solution contain 23 - 27 wt% nitric acid and 23 - 27 wt% hydrogen peroxide. Heat the mixed solution to 50 - 60 °C and continue the reaction for 25 - 40 minutes under the condition of blowing air to dissolve the remaining lead dioxide and obtain the leaching solution.

[0014] The concentration of nitric acid can be 23 wt%, 24 wt%, 25 wt%, 26 wt% or 27 wt%, or other values within this range; the concentration of hydrogen peroxide can be 23 wt%, 24 wt%, 25 wt%, 26 wt% or 27 wt%, or other values within this range.

[0015] The reaction temperature can be 50 °C, 55 °C or 60 °C, or other values within this range.

[0016] The reaction time can be 25 minutes, 30 minutes, 35 minutes or 40 minutes, or other values within this range.

[0017] Step S5: Reuse the leaching solution until the concentration of lead nitrate in it reaches 250 - 320 g / L. After filtration, it is transported to the electroplating production line for recycling; the treated titanium substrate is washed and then electroplated again for use.

[0018] Furthermore, the pretreatment in step S1 includes ultrasonic cleaning and countercurrent cleaning in sequence.

[0019] Furthermore, the ultrasonic cleaning process is: Place the waste lead dioxide anode in pure water at 40 - 50 °C and clean it with ultrasonic waves for 15 - 20 minutes; the countercurrent cleaning process uses two - stage countercurrent rinsing and the rinsing water is recycled. Specifically, the temperature of the pure water can be 40 °C, 45 °C or 50 °C, or other values within this range.

[0020] Furthermore, it also includes a step of recovering nickel and cobalt from the waste liquid after ultrasonic cleaning.

[0021] Further, in step S2, the reaction temperature is 43 - 47°C, and the reaction is carried out under stirring conditions; preferably, the reaction temperature is 45°C.

[0022] Further, in step S2, the surfactant is sodium dodecyl sulfate.

[0023] Further, step S2 further includes a waste liquid treatment step to remove calcium chloride and magnesium chloride from the waste liquid, and the purified water is recycled to the pretreatment process.

[0024] Further, in step S3, solution B includes 15 wt% nitric acid and 15 wt% hydrogen peroxide.

[0025] Further, in step S4, nitric acid and hydrogen peroxide are supplemented so that the mixed solution contains 25 wt% nitric acid and 25 wt% hydrogen peroxide.

[0026] Further, in step S4, the amount of air bubbled in is 0.4 - 0.8 L / min; specifically, the air flow rate can be 0.4 L / min, 0.5 L / min, 0.6 L / min, 0.7 L / min, or 0.8 L / min, or other values within this range.

[0027] Compared with the prior art, the method for recycling waste lead dioxide anodes provided by the present invention has the following beneficial effects:

[0028] First, for the method for recycling waste lead dioxide anodes provided by the present invention, the lead recovery rate ≥ 97% (≤ 85% for traditional methods), and the treatment time is shortened to 1.5 hours (3 hours for traditional processes), improving the treatment efficiency.

[0029] Second, for the method for recycling waste lead dioxide anodes provided by the present invention, the impurity content of the lead nitrate solution < 50 ppm (analyzed by ICP - MS) and can be directly used for electroplating; the treated titanium substrate has no structural damage and can be reused. After testing, the titanium substrate can be reused more than 10 times.

[0030] Third, for the method for recycling waste lead dioxide anodes provided by the present invention, the heavy metal recovery rate of the waste liquid > 95%, and the conductivity of the purified wastewater < 10 μS / cm, which can be recycled. Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0032] Figure 1XRD pattern of the titanium substrate treated by the method for recycling waste lead dioxide anodes of the present invention. Detailed implementation manners

[0033] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention and to make the above objects, features, and advantages of the present invention more apparent and understandable, the following further describes the specific implementation manners of the present invention.

[0034] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0035] Example 1

[0036] A method for recycling waste lead dioxide anodes includes the following steps:

[0037] Step S1, pretreatment: cleaning the waste lead dioxide anode to remove the electrolyte crystals on the surface;

[0038] Specifically, it includes ultrasonic cleaning and countercurrent cleaning in sequence. Among them, the ultrasonic cleaning process is: placing the waste lead dioxide anode in pure water at 40 - 50 °C and using ultrasonic waves to clean for 15 - 20 min to remove the electrolyte crystals such as nickel sulfate and cobalt sulfate on the surface; the countercurrent cleaning process uses two - stage countercurrent rinsing, and the rinsing water is recycled, and the recycling rate reaches 90%.

[0039] The waste liquid after ultrasonic cleaning is recycled for nickel and cobalt. In this embodiment, the waste liquid is recycled through ion - exchange resin, and the recovery rate of metals such as nickel and cobalt > 95%.

[0040] Step S2, preparing solution A, placing the pretreated waste anode in solution A and reacting for 30 - 50 min to remove the surface metal oxides such as calcium oxide and magnesium oxide; wherein solution A includes 10 - 12 wt% hydrochloric acid and 0.2 - 0.5 wt% surfactant;

[0041] Specifically, the reaction temperature is 43 - 47 °C, and the reaction is carried out under stirring conditions, and the stirring rate is 200 - 300 rpm; the surfactant is preferably sodium dodecyl sulfate.

[0042] The leaching solution after hydrochloric acid leaching contains magnesium chloride and calcium chloride, and then through waste liquid treatment, calcium chloride and magnesium chloride are removed, and the purified water can be reused in the pretreatment process.

[0043] Step S3: Prepare solution B. Place the used anode with the surface metal oxide removed into solution B and soak it at room temperature for 20 - 40 minutes to dissolve part of the lead dioxide.

[0044] Among them, solution B includes 13 - 18 wt% nitric acid and 13 - 18 wt% hydrogen peroxide. The reaction principle is:

[0045] PbO2 + HNO3 + H2O2 → Pb(NO3)2 + H2O

[0046] This step can dissolve 75 - 80% of the lead dioxide.

[0047] Step S4: Supplement nitric acid and hydrogen peroxide to make the mixed solution contain 23 - 27 wt% nitric acid and 23 - 27 wt% hydrogen peroxide. Heat the mixed solution to 50 - 60 °C and continue the reaction for 25 - 40 minutes under the condition of blowing air to dissolve the remaining lead dioxide and obtain the leaching solution.

[0048] Specifically, the amount of air blown in is 0.4 - 0.8 L / min.

[0049] Step S5: Reuse the leaching solution until the lead nitrate concentration in it reaches 250 - 300 g / L. After the leaching solution is filtered, it is transported to the electroplating production line for recycling; the treated titanium substrate is washed and electroplated again for use.

[0050] Among them, the reuse of the leaching solution means that when the conversion of lead dioxide in the used anode is complete, by supplementing the amounts of nitric acid and hydrogen peroxide to meet the requirements of primary leaching, the primary leaching treatment is carried out on the next batch of used anodes; then the amounts of nitric acid and hydrogen peroxide are supplemented again to make the mixed solution meet the requirements of deep leaching, and the remaining lead dioxide on the used anode is converted. This cycle continues until the lead nitrate concentration in the leaching solution reaches the electroplating requirement.

[0051] Example 2

[0052] A method for recycling used lead dioxide anodes includes the following steps:

[0053] Step S1: Pretreatment: Clean the used lead dioxide anode to remove the surface electrolyte crystals.

[0054] Specifically, place the used lead dioxide anode in pure water at 45 °C and clean it with 40 kHz ultrasonic waves for 15 minutes to remove the surface electrolyte crystals such as nickel sulfate and cobalt sulfate; then use two - stage counter - current rinsing to further clean the anode.

[0055] Step S2, prepare Solution A. Place the pretreated waste anode into Solution A. The reaction temperature is 45°C, and under stirring conditions (250 rpm), react for 35 minutes to dissolve the surface metal oxides such as calcium oxide and magnesium oxide. Solution A includes 10 wt% hydrochloric acid and 0.3 wt% sodium dodecyl sulfate.

[0056] Step S3, prepare Solution B. Place the waste anode with the surface metal oxides removed into Solution B and soak it at room temperature for 30 minutes to dissolve part of the lead dioxide. Solution B includes 15 wt% nitric acid and 15 wt% hydrogen peroxide.

[0057] Step S4, supplement nitric acid and hydrogen peroxide to make the mixed solution contain 25 wt% nitric acid and 25 wt% hydrogen peroxide. Heat the mixed solution to 55°C and continue to react for 30 minutes under the condition of blowing air (0.5 L / min) to dissolve the remaining lead dioxide and obtain the leaching solution.

[0058] Step S5, reuse the leaching solution until the lead nitrate concentration in it reaches 300 g / L. After the leaching solution is filtered, it is transported to the electroplating production line for recycling. The treated titanium substrate is washed and then electroplated and reused.

[0059] In this embodiment, the treatment method for the waste liquid generated in each step corresponds to that in Example 1 and will not be elaborated here.

[0060] The XRD pattern of the titanium substrate after the recycling treatment in this embodiment is as Figure 1 shown. It can be seen from Figure 1 that the peak positions of the recycled and untreated titanium substrates are the same, there is no titanium oxide peak, and no new phase is generated. At angles of 25.43, 32, and 49.04, the peaks of lead dioxide are shown, and the peak intensities are small, indicating that there is residual lead dioxide on the surface of the treated substrate, and the content is negligible.

[0061] Example 3

[0062] A method for recycling waste lead dioxide anodes, based on Example 2, omits Step S4, and the remaining steps are basically the same as those in Example 2.

[0063] Example 4

[0064] A method for recycling waste lead dioxide anodes, based on Example 2, replaces the reaction temperature in Step S4 with room temperature, and the remaining steps are basically the same as those in Example 2.

[0065] The following elaborates in detail on the method for recycling waste lead dioxide anodes of the present invention through specific applications.

[0066] Example 5

[0067] The method for recycling waste lead dioxide anode resources in Example 2 was applied to the treatment of waste titanium anodes in an electroplating factory to obtain Example 5. In Example 5, the technical parameters of the waste titanium anodes used are as follows:

[0068] 100 Kg of waste anode plates, and the mass percentages of lead and other elements are as follows:

[0069] Lead: 62%, Ni: 1.2%, Co: 0.8%, CaO: 2.5%.

[0070] The concentration of the recovered lead nitrate solution is 320 g / L, the content of impurity Ni is 12 ppm, and the content of Co is 8 ppm; the lead recovery rate is 98.5%, and the recovered titanium substrate is the same as the untreated substrate.

[0071] For the waste titanium anodes in this example, the traditional electrolysis method was used to recover lead, and the lead recovery rate was only 82%.

[0072] Example 6

[0073] The method for recycling waste lead dioxide anode resources in Example 3 was applied to the treatment of waste titanium anodes in an electroplating factory to obtain Example 6.

[0074] In Example 6, the technical parameters of the waste titanium anodes used are as follows:

[0075] 100 Kg of waste anode plates, and the mass percentages of lead and other elements are as follows:

[0076] Lead: 62%, Ni: 1.2%, Co: 0.8%, CaO: 2.5%.

[0077] The lead recovery rate in this example is 88.7%.

[0078] Example 7

[0079] The method for recycling waste lead dioxide anode resources in Example 4 was applied to the treatment of waste titanium anodes in an electroplating factory to obtain Example 7.

[0080] In Example 7, the technical parameters of the waste titanium anodes used are as follows:

[0081] 100 Kg of waste anode plates, and the mass percentages of lead and other elements are as follows:

[0082] Lead: 62%, Ni: 1.2%, Co: 0.8%, CaO: 2.5%.

[0083] The lead recovery rate in this example is 94.6%.

[0084] As can be seen from Examples 5 - 7, by adopting a two - stage nitric acid and hydrogen peroxide leaching process and increasing the reaction temperature for deep leaching, the lead recovery rate can be significantly improved.

[0085] Example 8

[0086] The method for recycling waste lead dioxide anode resources in Example 2 was applied to the treatment of lead - acid battery lead paste to obtain Example 8.

[0087] In Example 8, the technical parameters of the lead paste are as follows:

[0088] 50 Kg of lead paste, with 85% PbO₂ content and 8% sulfate impurities.

[0089] Lead recovery rate: 97.8%;

[0090] The recovered lead nitrate solution has a concentration of 305 g / L and a sulfate content of < 100 ppm.

[0091] For the lead paste in this example, using the traditional pyrometallurgical recovery process, the lead recovery rate is 88%.

[0092] Comparing the method for recycling waste lead dioxide anode resources of the present invention with the traditional method, the analysis of indicators such as energy consumption and metal residue in waste liquid is shown in Table 2:

[0093] Table 2: Recovery index parameters corresponding to different recovery methods

[0094] Index The present invention Pyrometallurgy Electrolytic reduction Lead recovery rate (%) ＞97 85-90 90-95 Energy consumption (kwh / ton) 120 500 300 Heavy metal residue in waste liquid <50ppm Untreated 200 - 500ppm Repeated times of titanium substrate >10 times Non - repeatable 3 - 5 times

[0095] It can be seen from this that the method for recycling waste lead dioxide anode resources of the present invention can improve the lead recovery rate, reduce energy consumption, reduce metal residue in waste liquid compared with the traditional recovery method, make the recovery method more environmentally friendly, and the recycled titanium substrate can be reused, further reducing the production energy consumption.

[0096] The above has made a detailed description of the embodiments of the present invention, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principle and spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. A method for recycling waste lead dioxide anodes, characterized in that, It includes the following steps: Step S1, pretreatment: Clean the waste lead dioxide anode to remove the electrolyte crystallization on the surface; Step S2, prepare solution A, place the pretreated waste anode in solution A, and react for 30 - 50 min to remove the metal oxides on the surface; Among them, solution A includes 10 - 12 wt% hydrochloric acid and 0.2 - 0.5 wt% surfactant; Step S3, prepare solution B, place the waste anode with the surface metal oxides removed in solution B, soak it at room temperature for 20 - 40 min to dissolve part of the lead dioxide; Among them, solution B includes 13 - 18 wt% nitric acid and 13 - 18 wt% hydrogen peroxide; Step S4, supplement nitric acid and hydrogen peroxide to make the mixed solution contain 23 - 27 wt% nitric acid and 23 - 27 wt% hydrogen peroxide, heat the mixed solution to 50 - 60 °C, and continue to react for 25 - 40 min under the condition of blowing air to dissolve the remaining lead dioxide to obtain the leaching solution; Step S5, reuse the leaching solution until the lead nitrate concentration in it reaches 250 - 320 g / L, filter it and then transport it to the electroplating production line for recycling; the treated titanium substrate is cleaned and electroplated again for use.

2. The method for recycling waste lead dioxide anodes according to claim 1, characterized in that, The pretreatment in step S1 includes ultrasonic cleaning and countercurrent cleaning carried out in sequence.

3. The method for recycling waste lead dioxide anodes according to claim 2, characterized in that, The ultrasonic cleaning process is: Place the waste lead dioxide anode in pure water at 40 - 50 °C and carry out ultrasonic cleaning for 15 - 20 min; the countercurrent cleaning process adopts two - stage countercurrent rinsing, and the rinsing water is recycled.

4. The method for recycling waste lead dioxide anodes according to claim 3, characterized in that, It also includes the step of recovering nickel and cobalt from the waste liquid after ultrasonic cleaning.

5. The method for recycling waste lead dioxide anodes according to claim 1, characterized in that, In step S2, the reaction temperature is 43 - 47 °C, and the reaction is carried out under stirring conditions.

6. The method for recycling waste lead dioxide anodes according to claim 1, characterized in that, In step S2, the surfactant is sodium dodecyl sulfate.

7. The method for recycling waste lead dioxide anodes according to claim 1, characterized in that, Step S2 also includes a waste liquid treatment step to remove calcium chloride and magnesium chloride in the waste liquid, and the purified water is reused in the pretreatment process.

8. The method for recycling waste lead dioxide anodes according to claim 1, characterized in that, In step S3, solution B includes 15 wt% nitric acid and 15 wt% hydrogen peroxide.

9. The method for recycling waste lead dioxide anodes according to claim 8, characterized in that, In step S4, supplement nitric acid and hydrogen peroxide to make the mixed solution contain 25 wt% nitric acid and 25 wt% hydrogen peroxide.

10. The method for recycling waste lead dioxide anodes according to claim 1, characterized in that, In step S4, the air blowing volume is 0.4 - 0.8 L / min.

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