When the lead is electrolyzed, about 1.6% to 1.75% of the lead anode slime of the crude lead is produced. Most of these anode muds adhere to the surface of the anode plate, and a small portion is detached from the anode and precipitated in the electrolytic cell due to agitation or production operation.
When using lead fluorosilicate electrolyte to produce electrolytic lead, according to the practice of most factories, lead anode mud contains a large amount of solution, which sometimes contains lead up to 323g / L, total acid amount 304g ∕ L (including free acid 78g ∕ L) and contains a small amount of undissolved additives. In order to recover these substances, the anode mud taken out from the electrolytic cell and scraped off from the residual electrode must first be subjected to precipitation filtration, and then in the anode mud stirring tank, the solid-liquid ratio is 1:1.2, and the temperature is raised by about 50 °C. Stirring and washing for more than 2 hours, the lead fluorosilicate, free acid and additives in the anode mud are fully dissolved in hot water for recovery. The washed anode mud is dehydrated by a centrifuge or a filter press to obtain a lead anode slime having a water content of about 30%.
When electrolytic lead, the crude lead anode contained gold, silver and bismuth almost entirely into the anode slime, and arsenic, antimony, copper, or the most part into the anode mud. Therefore, the composition of the lead anode mud is mainly determined by the coarse lead anode plate used. The main components of lead anode mud in some factories at home and abroad are listed in the table below.
The main components of lead anode mud in some factories at home and abroad
Factory name | Ingredient % | ||||
Au | Ag | Pb | Cu | Bi | |
1 Factory (China) | 0.02~0.07 | 8.0~14.0 | 10~25 | 0.5 to 1.5 | 4.0 to 25.0 |
2 Factory (China) | 0.001 | 5.01 | 17.45 | 1.17 | 2.00 |
3 Factory (China) | 0.003 | 1.85 | 15.14 | 1.07 | 3.20 |
4 Factory (China) | 0.02~0.045 | 8~10 | 6 to 10 | 2.0 | 10.0 |
5 Factory (China) | 0.025 | 2.63 | 8.81 | 1.32 | 5.53 |
Niihama (Japan) | 0.2 to 0.4 | 0.1 to 0.15 | 5~10 | 4~6 | 10-20 |
Kurosura (Japan) | 0.021 | 12.82 | 8.28 | 10.05 | |
Teller (Canada) | 0.016 | 11.50 | 19.70 | 1.80 | 2.10 |
Oloya (Peru) | 0.01 | 9.5 | 15.6 | 1.6 | 20.6 |
(continued in the table)
Factory name | Ingredient % | |||||
As | Sb | Sn | Fe | Te | total | |
1 Factory (China) | 5~20 | 10~30 | 0.1 to 0.5 | 76.84 (average) | ||
2 Factory (China) | 19.50 | 16.93 | 6.00 | 0.05~0.31 | 68.24 (average) | |
3 Factory (China) | 18.70 | 18.10 | 13.80 | 71.86 | ||
4 Factory (China) | 25~30 | 0.1 | 79.13 (average) | |||
5 Factory (China) | 0.67 | 54.30 | 0.38 | 73.67 | ||
Niihama (Japan) | 25~35 | 57.93 (average) | ||||
Kurosura (Japan) | 43.26 | 2.13 | 0.27 | 76.83 | ||
Teller (Canada) | 10.60 | 28.10 | 0.07 | 73.89 | ||
Oloya (Peru) | 4.6 | 33.0 | 0.74 | 85.65 | ||
The process of treating lead anode mud in different factories is different, which is related to the different raw materials, equipment and production conditions used. However, in addition to recycling precious metals such as gold and silver, each factory handles lead anode mud and tries to recover other useful metals as much as possible.
Aluminum
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