Method for preparing lead-based anode by using lead plaster of waste lead-acid battery

Abstract

The invention relates to the field of material preparation, and particularly discloses a method for preparing a lead-based anode by using lead plaster of a waste lead-acid battery. The preparation method of the lead-based anode comprises the following steps of: 1, washing waste lead paste to remove residual acid; 2, forced air drying and deacidification of the waste lead paste in a rotary kiln; step 3, melting the waste lead plaster in an electric furnace, and separating a Pb melt from PbSO4-PbOx-PbO2 scum; 4, cooling the scum, and performing ball milling and crushing to obtain particles with the particle size of less than or equal to 200 meshes; 5, the Pb melt is poured into a mold, the temperature is lowered to 330-350 DEG C, then heat preservation is conducted, the surface of Pb is evenly covered with dross particles through the sand blasting technology, and then natural cooling is conducted; and sixthly, the lead anode is turned over after being demolded, the temperature is increased to 330-350 DEG C, and then the other working face is subjected to sand blasting treatment. According to the method, high-value utilization of all components of the waste lead paste can be achieved, reliable combination of PbSO4-PbOx-PbO2 and a Pb matrix is achieved, and the lead-based anode meeting industrial application is obtained.

Description

Technical Field

[0001] The present invention relates to the field of material preparation, and specifically discloses a method for preparing a lead-based anode using waste lead-acid battery paste. Background Art

[0002] Lead-acid batteries have the advantages of safety, reliability, and low cost, and are widely used in fields such as low-speed electric bicycles, start-stop batteries, and uninterruptible power supplies. In China, recycled lead from waste lead-acid batteries accounts for more than 50% of the metal lead output. After waste lead-acid batteries are disassembled, crushed, and reselected, waste lead paste with main components of Pb, PbO, PbSO4, and PbO2 can be obtained. Currently, the mainstream process for recycling lead using waste lead paste is desulfurization - smelting - refining, which has a long process, high energy consumption, and a large discharge of lead-containing wastewater.

[0003] Lead-based anodes are the mainstream anodes used in non-ferrous metal electrowinning. During the electrowinning process, an oxide film layer gradually forms on the surface of the lead-based anode, and its composition is PbSO4 - PbO x - PbO2. However, the bonding strength between the oxide film layer and the substrate is not high, and it is easily detached under the continuous scouring of oxygen bubbles, resulting in continuous corrosion of the anode substrate. Summary of the Invention

[0004] In view of the problems that the composition of the oxide film layer on the surface of the lead-based anode is similar to that of the waste lead paste, and the bonding strength between the oxide film layer and the anode substrate is not high, the present invention proposes a method for preparing a lead-based anode using waste lead-acid battery paste.

[0005] The method for preparing a lead-based anode using waste lead-acid battery paste proposed by the present invention, wherein the lead-based anode is used for non-ferrous metal electrowinning, and the method comprises the following steps:

[0006] Send the waste lead paste for water washing to remove residual acid;

[0007] Send the deacidified waste lead paste to a rotary kiln for blast drying;

[0008] Send the dried waste lead paste to an electric furnace for heating and melting to form lead liquid and PbSO4 - PbO x - PbO2 scum;

[0009] Skim off the scum, cool it, and send it to a ball mill for grinding;

[0010] Pour the lead liquid into an anode mold, keep it warm after cooling to 330 - 350 °C;

[0011] Use the fine particles with a particle size of ≤ 200 mesh after ball milling the scum as the sandblasting medium, evenly spray it onto the surface of the lead anode in the anode mold, and after cooling, embed it into the lead anode to form a stable coating;

[0012] After the lead anode is demolded, it is turned over, heated to 330-350 °C, and then sandblasted on the other working surface. After cooling, a lead-based anode is obtained.

[0013] Preferably, the waste lead paste is washed with medium water to remove the residual acid until the acidity of the washing water no longer changes.

[0014] Preferably, the air-blowing drying temperature of the rotary kiln is controlled below 300 °C.

[0015] Preferably, the working temperature of the electric furnace is controlled at 380-500 °C.

[0016] Preferably, during sandblasting, the sandblasting speed should be such that it does not cause lead liquid to splash, and the dross particles completely and evenly cover the lead matrix.

[0017] The inventive concept and technical principle of the present invention are as follows:

[0018] (1) Treatment of waste lead paste in an electric furnace can efficiently separate the Pb melt and PbSO4-PbO x -PbO2 oxides: Traditional waste lead paste needs to undergo desulfurization, high-temperature smelting, and refining to regenerate metallic lead, which has high energy consumption and high costs in the process. In an electric furnace, by utilizing the immiscible characteristics of the Pb melt and PbSO4-PbO x -PbO2 oxides, the Pb melt and the oxide components can be efficiently separated.

[0019] (2) High-value utilization of PbSO4-PbO x -PbO2 in waste lead paste as a lead anode coating: Given that the oxide film layer formed on the surface of the lead anode during the electrowinning process is similar in composition to the oxides in the waste lead paste, it can be directly used as a prefabricated oxide film layer, thereby reducing the rapid corrosion of the lead anode matrix at the initial stage of electrowinning.

[0020] (3) Using Pb in the waste lead paste as the Pb matrix and realizing reliable bonding between the matrix and the lead paste oxide particles during its solidification process: The Pb melt obtained in the electric furnace is directly cast into a Pb anode matrix. Using sandblasting technology, the ground lead paste oxide components are evenly dispersed on the surface of the Pb matrix. During the solidification process, metallurgical bonding between the Pb matrix and the oxide components is achieved, enhancing the bonding stability between the prefabricated oxide film layer and the matrix. Detailed implementation mode

[0021] The content of the present invention will be described in detail in conjunction with the following embodiments.

[0022] Example 1

[0023] The waste lead paste is washed with reclaimed water (liquid-solid ratio of 2:1) to remove the residual acid until the liquid pH changes by <0.1; the deacidified waste lead paste is dried by air blowing in a rotary kiln, and the flue gas temperature of the rotary kiln is controlled at 280 ± 10 °C; the waste lead paste is melted in an electric furnace, and the melt temperature is controlled at 450 °C, and the Pb melt and PbSO4-PbOx - After the PbO₂ scum is stratified, the scum is fished out; after the scum is naturally cooled, it is ball-milled, crushed, and particles ≤200 mesh are screened out; the Pb melt in the electric furnace is poured into the lead anode mold, and after cooling to 350 °C, it is kept warm; using sandblasting technology, the scum particles are evenly covered on the surface of Pb, and the thickness of the scum layer is controlled at 20 μm, and then it is naturally cooled; after the lead anode is demolded, it is turned over, heated to 350 °C, and the other working surface is sandblasted, and after cooling, a lead-based anode is obtained. This lead-based anode is subjected to constant current polarization (500 Am -2 ) for 72 h in a simulated zinc electrowinning electrolyte, and the anode potential is 50 mV lower than that of the traditional Pb-Ag (0.6 wt.%) plate, and the anode weight loss rate is reduced by 81%.

[0024] Example 2

[0025] The waste lead paste is washed with reclaimed water (liquid-solid ratio of 3:1) to remove residual acid until the liquid pH changes <0.05; the deacidified waste lead paste is dried by blowing air in a rotary kiln, and the flue gas temperature of the rotary kiln is controlled at 270 ± 10 °C; the waste lead paste is melted by an electric furnace, the melt temperature is controlled at 390 °C, and the Pb melt and PbSO₄-PbO x - After the PbO₂ scum is stratified, the scum is fished out; after the scum is naturally cooled, it is ball-milled, crushed, and particles ≤200 mesh are screened out; the Pb melt in the electric furnace is poured into the lead anode mold, and after cooling to 330 °C, it is kept warm. Using sandblasting technology, the scum particles are evenly covered on the surface of Pb, and the thickness of the scum layer is controlled at 10 μm, and then it is naturally cooled; after the lead anode is demolded, it is turned over, heated to 330 °C, and the other working surface is sandblasted, and after cooling, a lead-based anode is obtained. This lead-based anode is subjected to constant current polarization (500 Am -2 ) for 72 h in a simulated zinc electrowinning electrolyte, and the anode potential is 45 mV lower than that of the traditional Pb-Ag (0.6 wt.%) plate, and the anode weight loss rate is reduced by 76%.

[0026] Example 3

[0027] The waste lead paste is washed with reclaimed water (liquid-solid ratio of 2:1) to remove residual acid until the liquid pH changes <0.1; the deacidified waste lead paste is dried by blowing air in a rotary kiln, and the flue gas temperature of the rotary kiln is controlled at 250 ± 10 °C; the waste lead paste is melted by an electric furnace, the melt temperature is controlled at 480 °C, and the Pb melt and PbSO₄-PbO x - After the PbO₂ scum is stratified, the scum is fished out; after the scum is naturally cooled, it is ball-milled, crushed, and particles ≤200 mesh are screened out; the Pb melt in the electric furnace is poured into the lead anode mold, and after cooling to 340 °C, it is kept warm. Using sandblasting technology, the scum particles are evenly covered on the surface of Pb, and the thickness of the scum layer is controlled at 30 μm, and then it is naturally cooled; after the lead anode is demolded, it is turned over, heated to 340 °C, and the other working surface is sandblasted, and after cooling, a lead-based anode is obtained. This lead-based anode is subjected to constant current polarization (500 Am -2)After 72 h, the anode potential is 65 mV lower than that of the traditional Pb-Ag (0.6 wt%) plate, and the anode weight loss rate is reduced by 65%.

Claims

1. A method for preparing a lead-based anode using lead paste from waste lead-acid batteries, characterized in that, The lead-based anode is used for electrowinning non-ferrous metals, and the method comprises the following steps: Send the waste lead paste for water washing to remove residual acid; Send the deacidified waste lead paste to a rotary kiln for air drying; The dry waste lead paste is sent to an electric furnace for heating and melting to form lead liquid and PbSO4-PbO x -PbO2 scum; Skim off the dross, cool it and then send it to a ball mill for fine grinding; Pour the lead liquid into an anode mold, keep it warm after cooling to 330-350 °C; Use the fine particles with a particle size of ≤200 mesh after ball milling the dross as the sandblasting medium, evenly spray it onto the surface of the lead anode in the anode mold, and embed it into the lead anode after cooling to form a stable coating; After the lead anode is demolded, turn it over, raise the temperature to 330-350 °C and then sandblast the other working surface, and obtain the lead-based anode after cooling.

2. The method for preparing a lead-based anode using lead paste of waste lead-acid batteries according to claim 1, characterized in that, Wash the residual acid of the waste lead paste with water until the acidity of the washing water no longer changes.

3. The method for preparing a lead-based anode using waste lead-acid battery lead paste according to claim 1, characterized in that, Control the air drying temperature of the rotary kiln below 300 °C.

4. The method for preparing a lead-based anode using lead paste of waste lead-acid batteries according to claim 1, characterized in that, Control the working temperature of the electric furnace at 380-500 °C.

5. The method for preparing a lead-based anode using lead paste from waste lead-acid batteries according to claim 1, characterized in that, During sandblasting, the sandblasting speed should be appropriate so as not to cause lead liquid splashing, and the dross particles should completely and evenly cover the lead matrix.