Method for preparing lead oxide from copper smelting electric dust

Abstract

The application provides a method for preparing lead oxide from copper smelting electric dust ash, and comprises the following process steps: (1) sulfuric acid leaching: adding sulfuric acid; (2) acetic acid leaching: adding acetic acid; (3) ammonia water-sodium acetate leaching: adding ammonia water and sodium acetate; (4) lead precipitation: adding sodium oxalate; (5) lead oxide. The application adopts twice acid leaching, on the one hand, valuable metals in the copper smelting electric dust ash except lead are effectively leached; on the other hand, impurity elements in the acid leaching residue are reduced, and high-purity lead oxide products are prepared subsequently. The lead element in the acid leaching residue is leached by ammonia water-sodium acetate, and under the weak alkaline condition, the leaching of lead is beneficial, and the leaching of other elements such as copper, arsenic and zinc is inhibited.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of smelting, and particularly relates to a method for preparing lead oxide from copper smelting electric dust ash. BACKGROUND

[0002] In the copper pyrometallurgical process, valuable elements such as volatile elements lead, zinc and arsenic enter the gas phase with smelting flue gas in the high-temperature smelting process, and a small part of copper enters the dust with mechanical inclusions, and is collected by an electric dust collector to become copper smelting electric dust ash. The copper smelting electric dust ash is a typical hazardous solid waste, but it contains valuable elements such as gold, silver, copper, lead, zinc and arsenic, and the content of lead is 20%-40%, which has a high resource value. At present, the recovery of lead from copper smelting electric dust ash generally adopts an acid leaching electric dust ash and an acid leaching slag recycling lead system pyrometallurgical system, and finally the lead is recycled in the form of lead ingot. This method has a complex process, a low lead recovery rate and a high production cost.

[0003] CN 104789776 B discloses a method for recovering lead oxide from lead oxide-containing waste, and the main steps are as follows: (1) contacting the lead oxide-containing waste with a complexing agent solution, and performing solid-liquid separation on the mixture after the contact to obtain a lead-containing filtrate and a filter residue; (2) reacting the lead-containing filtrate with a precipitating agent, and performing solid-liquid separation on the reaction product to obtain a lead salt precipitate and a regenerated complexing agent filtrate, and returning the complexing agent filtrate to the dissolution process of step (1); and (3) decomposing the lead salt precipitate to obtain PbO. The raw material of this method is derived from lead smelting, and the lead oxide in the lead oxide-containing waste reacts with the complexing agent to generate a substance dissolved in the solution, and then is precipitated to obtain lead oxide. This method has obvious defects: on the one hand, the lead-containing waste needs to be treated at high temperature, and some harmful substances (such as diarsenic trioxide and sulfate decomposed into sulfur dioxide) volatilize, which needs to be recycled at a high cost; on the other hand, only the lead-containing waste can be treated, and if other valuable metals are contained, the complexing agent may react with other metal oxides, causing the content of impurities in the lead oxide to be too high.

[0004] CN 104843772 B discloses "a method for recovering lead chloride from sintering ash by acetic acid leaching and preparing lead monoxide", the sintering machine head flue gas electric dust of steel plant is first prepared into a suspension slurry, the tail slurry after separating the iron concentrate is prepared into a concentrated tail mud containing lead by precipitation or filtration separation; then dilute hydrochloric acid solution is added for chlorination reaction, and the lead-containing chlorination tail mud is prepared by precipitation or filtration separation and water washing; then acetic acid-sodium acetate solution is added, and the mixed solution containing lead acetate and sodium chloride is prepared by precipitation or filtration separation and water washing; then Na2CO3 is added for precipitation reaction, and the obtained solid is dried and roasted to obtain lead monoxide product. The method uses acetic acid-sodium acetate solution to leach lead chloride residue, and because acetic acid provides hydrogen ions, part of the dissolved lead reacts with chloride ions to form lead chloride precipitate, resulting in low recovery rate; on the other hand, if the sintering ash contains precious metals gold and silver, the use of dilute hydrochloric acid for chlorination reaction will cause part of the gold and silver to dissolve in the solution, resulting in loss of gold and silver. SUMMARY

[0005] The present application provides a method for preparing lead oxide from copper smelting electric dust.

[0006] The technical scheme of the present application is as follows: a method for preparing lead oxide from copper smelting electric dust, comprising the following process steps:

[0007] (1) Sulfuric acid leaching: copper smelting electric dust is slurried according to a solid-liquid mass ratio of 1:(2-8) with water, then sulfuric acid is added according to a solution acidity of 5%-30%, and stirring is carried out at 20-90°C for 0.5-4.0h, followed by pressure filtration, and the filter residue enters the next process, and the filtrate enters a water treatment system for recovery of valuable metals such as copper, arsenic and zinc;

[0008] (2) Acetic acid leaching: the filter residue produced in step (1) is slurried according to a solid-liquid mass ratio of 1:(1-4) with water, then acetic acid is added according to a solution acidity of 5%-10%, and stirring is carried out at 20-90°C for 0.5-4.0h, followed by pressure filtration, and the filter residue A enters the next process, and the filtrate is passed into hydrogen sulfide gas for recovery of copper, and the amount of hydrogen sulfide gas used is H2S / Cu of 1-1.5:1, followed by pressure filtration, and the filter residue B returns to a fire smelting system, and the filtrate returns to acetic acid leaching;

[0009] (3) Ammonia water-sodium acetate leaching: the filter residue A produced in step (2) is slurried according to a solid-liquid mass ratio of 1:(2-8) with water, then ammonia water and sodium acetate are added according to a molar ratio of 1:(5-20) with a concentration of 10%-30%, and stirring is carried out at 20-90°C for 0.5-4.0h, followed by pressure filtration, and the filter residue returns to a fire smelting system for recovery of precious metals such as gold and silver, and the filtrate enters the next process;

[0010] (4) Lead precipitation: the filtrate produced in step (3) is precipitated with Pb(NO3)2 according to a solid-liquid mass ratio of 1:(1-2) to prepare a lead chloride precipitate, and the precipitate is washed with water and dried to obtain lead chloride; 2+C2O4 2- Mole ratio 1: (1~1.5) add sodium oxalate, stirring at room temperature for 0.5h~4.0h, filter pressing, the filter residue enters the next step, the filtrate returns to step (3);

[0011] (5) Lead oxide: the filter residue produced in step (4) is put into a calcining furnace, calcined at 500~800℃ for 6~12h to obtain lead oxide powder;

[0012] Preferably, the main chemical reactions are as follows:

[0013] CuO + H2SO4 = CuSO4 + H2O

[0014] PbO + H2SO4 = PbSO4 + H2O

[0015] ZnO + H2SO4 = ZnSO4 + H2O

[0016] CuO + 2CH3COOH = Cu(CH3COO)2 + H2O

[0017] PbSO4 + 2CH3COONa = Pb(CH3COO)2 + Na2SO4

[0018] Pb(CH3COO)2 + Na2C2O4 = PbC2O4↓ + 2CH3COONa

[0019] Preferably, the filter residue produced in step (1) contains Cu≤1.0%, As≤2.0%, Zn≤1.0%, Fe≤1.0%, and Pb≥45%;

[0020] Preferably, the filter residue A produced in step (2) contains Cu≤0.5%, As≤1.0%, Zn≤0.5%, Fe≤0.5%, and Pb≥50%;

[0021] Preferably, the filtrate produced in step (3) contains Cu≤0.1mg / L, As≤0.1mg / L, Zn≤0.1mg / L, Fe≤0.1mg / L, and Pb≥10000mg / L;

[0022] Preferably, the filter residue produced in step (4) contains Cu≤0.01%, As≤0.01%, Zn≤0.01%, Fe≤0.01%, and Pb≥70%;

[0023] Preferably, the lead oxide produced in step (5) contains PbO≥99.0%, Cu≤0.01%, As≤0.01%, Zn≤0.01%, and Fe≤0.01%.

[0024] The beneficial effects of the present application are: the present application adopts sulfuric acid-acetic acid two-stage leaching, and valuable metal elements (except lead) in copper smelting electric dust ash are effectively recovered; lead elements in the acid leaching residue are leached by ammonia water-sodium acetate, the lead leaching rate is high, and the impurity element leaching rate is low; the lead oxide prepared from the copper smelting electric dust ash has high purity, the valuable metal recovery rate is high in the preparation process, and the environmental protection concept of turning waste into treasure is realized. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The process flow chart of the present application. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0027] In the description of the present application, it should be understood that the terms “upper”, “lower”, “front”, “back”, “left”, “right”, “top”, “bottom”, “inner”, “outer” and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0028] Embodiment 1:

[0029] The main components of the copper smelting electric dust ash are Au: 5.36 g / t, Ag: 52.34 g / t, Fe: 2.31%, Cu: 9.99%, Pb: 35.21%, Zn: 4.68%, As: 5.98%, and S: 9.85%.

[0030] The copper smelting electric dust ash is slurried by adding water according to a solid-liquid mass ratio of 1:4, and sulfuric acid is added according to a solution acidity of 20%, and stirred at 80°C for 2.0h, and then pressure filtered, and the filter residue enters the next process, and the filtrate enters a water treatment system to recover valuable metals such as copper, arsenic and zinc.

[0031] The filter residue in the above step is slurried by adding water according to a solid-liquid mass ratio of 1:2, and acetic acid is added according to a solution acidity of 10%, and stirred at 80°C for 2.0h, and then pressure filtered, and the filter residue A enters the next process, and the filtrate is passed into hydrogen sulfide gas to recover copper, and the amount of hydrogen sulfide gas used is H2S / Cu=1.2:1, and then pressure filtered, and the filter residue B returns to a fire smelting system, and the filtrate returns to acetic acid leaching.

[0032] The filter residue A is slurried with water at a solid-liquid mass ratio of 1:4, and then 20% ammonia water and sodium acetate are added at a molar ratio of 1:10, and stirred at 80°C for 2.0h, filtered, and the filter residue is returned to a gold and silver recovery system in a fire smelting system, and the filtrate is subjected to the next process.

[0033] The filtrate is subjected to Pb 2+ / C2O4 2- molar ratio of 1:1.3, stirred at room temperature for 2.0h, filtered, and the filter residue is subjected to the next process, and the filtrate is returned to a lead leaching process. The filter residue is placed in a calcination furnace and calcined at 600°C for 8h to obtain lead oxide powder.

[0034] Example 2:

[0035] The main components of the copper smelting electric dust ash are Au: 5.36g / t, Ag: 52.34g / t, Fe: 2.31%, Cu: 9.99%, Pb: 35.21%, Zn: 4.68%, As: 5.98%, and S: 9.85%.

[0036] The copper smelting electric dust ash is slurried with water at a solid-liquid mass ratio of 1:4, and then 10% sulfuric acid is added at a solution acidity, and stirred at 60°C for 1.0h, filtered, and the filter residue is subjected to the next process, and the filtrate is subjected to a copper, arsenic, and zinc recovery process in a water treatment system.

[0037] The filter residue of the above step is slurried with water at a solid-liquid mass ratio of 1:2, and then 10% acetic acid is added at a solution acidity, and stirred at 60°C for 1.0h, filtered, and the filter residue A is subjected to the next process, and the filtrate is subjected to copper recovery by passing hydrogen sulfide gas, the amount of hydrogen sulfide gas is 1.3:1, and the filter residue B is returned to a fire smelting system, and the filtrate is returned to an acetic acid leaching process.

[0038] The filter residue is slurried with water at a solid-liquid mass ratio of 1:4, and then 15% ammonia water and sodium acetate are added at a molar ratio of 1:10, and stirred at 60°C for 2.0h, filtered, and the filter residue is returned to a gold and silver recovery system in a fire smelting system, and the filtrate is subjected to the next process.

[0039] The filtrate is subjected to Pb 2+ / C2O4 2- molar ratio of 1:1.1, stirred at room temperature for 2.0h, filtered, and the filter residue is subjected to the next process, and the filtrate is returned to a lead leaching process. The filter residue is placed in a calcination furnace and calcined at 800°C for 6h to obtain lead oxide powder.

[0040] Comparative Example 1:

[0041] The main components of copper smelting electric dust ash are Au: 5.36 g / t, Ag: 52.34 g / t, Fe: 2.31%, Cu: 9.99%, Pb: 35.21%, Zn: 4.68%, As: 5.98%, and S: 9.85%.

[0042] The copper smelting electric dust ash is slurried by adding water in a solid-liquid mass ratio of 1:4, and then sulfuric acid is added according to a solution acidity of 20%, and stirring is performed at 80°C for 2.0h, pressure filtration is performed, the filter residue enters the next process, and the filtrate enters a water treatment system to recover valuable metals such as copper, arsenic, and zinc.

[0043] The filter residue of the above step is slurried by adding water in a solid-liquid mass ratio of 1:2, and then sulfuric acid is added according to a solution acidity of 10%, and stirring is performed at 80°C for 2.0h, pressure filtration is performed, the filter residue A enters the next process, hydrogen sulfide gas is introduced into the filtrate to recover copper, the amount of hydrogen sulfide gas used is H2S / Cu of 1.2:1, pressure filtration is performed, the filter residue B returns to a fire smelting system, and the filtrate returns to a secondary sulfuric acid leaching process.

[0044] The filter residue of the above step is slurried by adding water in a solid-liquid mass ratio of 1:4, and then ammonia and sodium acetate are added according to an ammonia-sodium acetate molar ratio of 1:10 and a concentration of 20%, and stirring is performed at 80°C for 2.0h, pressure filtration is performed, the filter residue returns to a fire smelting system to recover precious metals such as gold and silver, and the filtrate enters the next process.

[0045] The filtrate of the above step is added with sodium oxalate according to a Pb 2+ / C2O4 2- molar ratio of 1:1.3, stirring is performed at room temperature for 2.0h, pressure filtration is performed, the filter residue enters the next process, and the filtrate returns to a lead leaching process. The filter residue is placed in a calcination furnace and calcined at a high temperature of 600°C for 8h to obtain lead oxide powder.

[0046] Comparative Example 2:

[0047] The main components of copper smelting electric dust ash are Au: 5.36 g / t, Ag: 52.34 g / t, Fe: 2.31%, Cu: 9.99%, Pb: 35.21%, Zn: 4.68%, As: 5.98%, and S: 9.85%.

[0048] The copper smelting electric dust ash is slurried by adding water in a solid-liquid mass ratio of 1:4, and then sulfuric acid is added according to a solution acidity of 10%, and stirring is performed at 60°C for 1.0h, pressure filtration is performed, the filter residue enters the next process, and the filtrate enters a water treatment system to recover valuable metals such as copper, arsenic, and zinc.

[0049] The filter residue of the above step was slurried with water at a solid-liquid mass ratio of 1:2, then 10% sulfuric acid was added according to the solution acidity, stirred at 60°C for 1.0 h, pressure filtered, the filter residue A entered the next process, the filtrate was recycled copper by passing in hydrogen sulfide gas, the amount of hydrogen sulfide gas was H2S / Cu of 1.3:1, pressure filtered, the filter residue B returned to the fire smelting system, and the filtrate returned to the secondary sulfuric acid leaching.

[0050] The filter residue of the above step was slurried with water at a solid-liquid mass ratio of 1:4, then 15% ammonia and sodium acetate were added according to the ammonia-sodium acetate molar ratio of 1:10, stirred at 60°C for 2.0 h, pressure filtered, the filter residue returned to the fire smelting system to recycle gold, silver and other precious metals, and the filtrate entered the next process.

[0051] The filtrate of the above step was passed through Pb 2+ / C2O4 2- 1.1 at room temperature for 2.0 h, pressure filtered, the filter residue entered the next process, and the filtrate returned to the lead leaching process. The filter residue was put into a calcining furnace and calcined at 800°C for 6 h to obtain lead oxide powder.

[0052] Comparative Example 3:

[0053] The main components of the copper smelting electric dust ash were as follows: Au: 5.36 g / t, Ag: 52.34 g / t, Fe: 2.31%, Cu: 9.99%, Pb: 35.21%, Zn: 4.68%, As: 5.98%, and S: 9.85%.

[0054] The copper smelting electric dust ash was slurried with water at a solid-liquid mass ratio of 1:4, then 20% sulfuric acid was added according to the solution acidity, stirred at 80°C for 2.0 h, pressure filtered, the filter residue entered the next process, and the filtrate entered the water treatment system to recycle copper, arsenic, zinc and other valuable metals.

[0055] The filter residue of the above step was slurried with water at a solid-liquid mass ratio of 1:2, then 10% sulfuric acid was added according to the solution acidity, stirred at 60°C for 1.0 h, pressure filtered, the filter residue A entered the next process, the filtrate was recycled copper by passing in hydrogen sulfide gas, the amount of hydrogen sulfide gas was H2S / Cu of 1.3:1, pressure filtered, the filter residue B returned to the fire smelting system, and the filtrate returned to the secondary sulfuric acid leaching.

[0056] The filter residue of the above step was slurried with water at a solid-liquid mass ratio of 1:4, then 20% acetic acid and sodium acetate were added according to the acetic acid-sodium acetate molar ratio of 1:10, stirred at 80°C for 2.0 h, pressure filtered, the filter residue returned to the fire smelting system to recycle gold, silver and other precious metals, and the filtrate entered the next process.

[0057] The filtrate of the above step was passed through Pb 2+ / C2O4 2-Sodium oxalate was added at a molar ratio of 1:1.3, stirred at room temperature for 2.0 h, filtered by pressure, and the filter residue was sent to the next process. The filtrate was then used for lead leaching. The filter residue was placed in a calcination furnace and calcined at 600℃ for 8 h to obtain lead oxide powder.

[0058] Comparative Example 4:

[0059] The main components of copper smelting electrostatic ash are: Au: 5.36 g / t, Ag: 52.34 g / t, Fe: 2.31%, Cu: 9.99%, Pb: 35.21%, Zn: 4.68%, As: 5.98%, and S: 9.85%.

[0060] Copper smelting electrostatic ash is slurried by adding water at a solid-liquid mass ratio of 1:4, and then sulfuric acid is added according to the solution acidity of 10%. The mixture is stirred at 60°C for 1.0 h, then filtered. The filter residue enters the next process, and the filtrate enters the water treatment system to recover valuable metals such as copper, arsenic, and zinc.

[0061] The filter residue from the above steps is slurried with water at a solid-liquid mass ratio of 1:2, and then acetic acid is added according to the solution acidity of 10%. The mixture is stirred at 60°C for 1.0 h and then filtered by pressure. This filter residue A enters the next process. The filtrate is passed through hydrogen sulfide gas to recover copper. The hydrogen sulfide gas dosage (H2S / Cu) is 1.3:1. The mixture is then filtered by pressure. This filter residue B enters the remelting process system, and the filtrate is returned to acetic acid for leaching.

[0062] The above filter residue was slurried with water at a solid-liquid mass ratio of 1:4. Then, acetic acid and sodium acetate were added at a molar ratio of 1:10 and a concentration of 15%. The mixture was stirred at 60°C for 2.0 hours, filtered, and the filter residue was smelted using a reflux smelting system to recover precious metals such as gold and silver. The filtrate was then used in the next process.

[0063] The above filtrate was processed according to Pb 2+ / C2O4 2- Sodium oxalate was added at a molar ratio of 1:1.1, stirred at room temperature for 2.0 h, filtered by pressure, and the filter residue was sent to the next process. The filtrate was then used for lead leaching. The filter residue was placed in a calcination furnace and calcined at 800℃ for 6 h to obtain lead oxide powder.

[0064] Table of Examples and Comparative Examples

[0065]

[0066]

[0067]

[0068] The lead oxide obtained in Example 1 and Example 2 contains 92.54% lead (lead oxide: 99.69%) and 92.37% lead (lead oxide: 99.51%) respectively, and the purity of lead oxide is more than 99.5% and the impurity content is less than 0.01%.

[0069] In Comparative Example 1 and Comparative Example 2, sulfuric acid is used for secondary acid leaching and impurity removal, and the secondary leaching residue contains a high amount of impurities, resulting in a high amount of impurities in the lead oxide, and the lead oxide contains 91.58% lead (lead oxide: 98.65%) and 91.47% lead (lead oxide: 98.54%) respectively, and the purity of lead oxide is less than 99.0%.

[0070] In Comparative Example 3 and Comparative Example 4, acetic acid-sodium acetate solution is used for lead leaching, and a small amount of copper, arsenic, zinc and iron is leached under acidic conditions, resulting in a high amount of impurities in the lead-rich solution, a low purity of lead oxide, and a low lead recovery rate; the lead oxide contains 90.24% lead (lead oxide: 97.22%) and 89.64% lead (lead oxide: 96.57%) respectively, and the purity of lead oxide is less than 99.0%.

[0071] The above is a further detailed description of the present application in combination with specific preferred embodiments, and the specific implementation of the present application should not be limited to these descriptions. For ordinary skilled persons in the technical field to which the present application belongs, a number of simple deductions or substitutions can be made without departing from the concept of the present application, and all of them should be considered as falling within the protection scope of the present application.

Claims

1. A method for preparing lead oxide from copper smelting electrostatic ash, characterized in that... The process includes the following steps: (1) Sulfuric acid leaching: Copper smelting electro-dust is slurried with water at a solid-liquid mass ratio of 1:(2-8), and then sulfuric acid is added at a solution acidity of 5%-30%. The mixture is stirred at 20-90 °C for 0.5 h-4.0 h, then filtered. The filter residue enters the next process, and the filtrate enters the water treatment system to recover valuable metals such as copper, arsenic, and zinc. The resulting filter residue contains Cu≤1.0%, As≤2.0%, Zn≤1.0%, Fe≤1.0%, and Pb≥45%. (2) Acetic acid leaching: The filter residue produced in step (1) is slurried with water at a solid-liquid mass ratio of 1:(1~4), and then acetic acid is added at a solution acidity of 5%~10%. The mixture is stirred at 20~90 ℃ for 0.5 h~4.0 h, and then filtered. This filter residue A enters the next process. The filtrate is passed through hydrogen sulfide gas to recover copper. The amount of hydrogen sulfide gas used (H2S / Cu) is (1~1.5):

1. The mixture is then filtered. This filter residue B is returned to the smelting system. The filtrate is returned to acetic acid leaching. The resulting filter residue A contains Cu≤0.5%, As≤1.0%, Zn≤0.5%, Fe≤0.5%, and Pb≥50%. (3) Ammonia-sodium acetate leaching: The filter residue A produced in step (2) is slurried with water at a solid-liquid mass ratio of 1:(2-8), and then ammonia and sodium acetate are added at a concentration of 10%-30% at a molar ratio of 1:(5-20). The mixture is stirred at 20-90 °C for 0.5 h-4.0 h, filtered, and the filter residue is smelted by the reflux method to recover precious metals such as gold and silver. The filtrate enters the next process. The filtrate contains Cu≤0.1 mg / L, As≤0.1 mg / L, Zn≤0.1 mg / L, Fe≤0.1 mg / L, and Pb≥10000 mg / L. (4) Lead precipitation: The filtrate produced in step (3) is prepared according to the Pb standard. 2+ / C2O4 2- Sodium oxalate was added at a molar ratio of 1:(1~1.5), stirred at room temperature for 0.5 h~4.0 h, and then filtered under pressure. The filter residue was sent to the next step, and the filtrate was returned to step (3). The resulting filter residue contained Cu≤0.01%, As≤0.01%, Zn≤0.01%, Fe≤0.01%, and Pb≥70%. (5) Lead oxide: The filter residue produced in step (4) is placed in a roasting furnace and roasted at a high temperature of 500~800 ℃ for 6~12 h to obtain lead oxide powder. The composition of the produced lead oxide is: PbO≥99.0%, Cu≤0.01%, As≤0.01%, Zn≤0.01%, Fe≤0.01%.

2. The method for preparing lead oxide from copper smelting electrostatic ash as described in claim 1, characterized in that... The main chemical reactions that occur are as follows: CuO + H₂SO₄ = CuSO₄ + H₂O PbO + H₂SO₄ = PbSO₄ + H₂O ZnO + H₂SO₄ = ZnSO₄ + H₂O CuO + 2CH3COOH = Cu(CH3COO)2 + H2O PbSO4+2CH3COONa=Pb(CH3COO)2+Na2SO4 Pb(CH3COO)2+Na2C2O4=PbC2O4↓+2CH3COONa.

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