Gold electrolytic refining
2020-08-21 11:07Introduction：Gold electrolytic refining Gold electrolytic refining takes coarse gold plate as anode , pure gold plate as cathode , electrolysis is carried out in hydrochloric acid medium , and the electrolytic gold with the gold content higher than 99.
Gold electrolytic refining
Gold electrolytic refining takes coarse gold plate as anode , pure gold plate as cathode , electrolysis is carried out in hydrochloric acid medium , and the electrolytic gold with the gold content higher than 99.95 % is produced .
The silver electrolytic anode slime containing less than 10% silver was mixed with a small amount of borax, nitrite and glass powder, and the anode plate containing more than 90% gold was cast by smelting slag at 1200~1300 ℃.
There are two kinds of electrolyte preparation: aqua regia method and electrolysis method. The aqua regia method is to dissolve the pure gold powder in the king's water. After the gold is completely dissolved, the nitric acid in the solution is removed by heating to remove the nitrate. The disadvantage of this method is the difficulty of removing nitrate.
Electrolytic liquid-making method has been widely used in recent years. Membrane electrolysis is used in electrolysis. The electrolysis conditions are basically the same as that of gold electrolysis. The electrolysis conditions are basically the same as those of gold electrolysis. The electrolysis conditions are basically the same as those of gold electrolysis. The electrolysis conditions are basically the same as those of gold electrolysis. The electrolysis conditions are basically the same as those of gold electrolysis. The electrolysis conditions are basically the same as gold electrolysis. Under the conditions of current density 1000~1500A/m2 and tank voltage of 3~4V, the electrolyte containing 380~450g / L gold can be prepared by using 25~30% hydrochloric acid solution.
The technical conditions of gold electrolysis are as follows: electrolytic solution containing 60~120g / l gold, hydrochloric acid 50~200g / l, cathode current density 200~700A /m2, cell voltage 0.4 ~ 1.0V, center distance of the same electrode 80 ~ 120mm, electrolyte temperature 50 ~ 75 ℃. Electrolyte does not circulate, air stirring. In order to prevent anodic passivation caused by silver chloride covering on the anode surface, the direct current is fed into the electrolytic cell at the same time, and the ratio of AC current intensity to DC current intensity is (1.5~2.00): 1.
During electrolysis, the anode should be removed every 8 hours to remove the silver chloride sludge covered on its surface, and then into the tank to continue electrolysis. Gold electrolytic anode mud contains about 90% silver chloride and 1.0% ~10% gold, which is usually cast into anode plate to return to silver electrolysis. Take out the cathode 80~100 hours after electrolysis and replace a new cathode to continue electrolysis. Wash the surface electrolyte with water, soak it in dilute ammonia for 4 hours, wash it, then soak it in nitric acid for 8 hours, then wash it and melt the gold ingot.
The replaced electrolytic waste liquid filtrates the anode mud and passes through the sulfur dioxide gas or restores the gold with ferrous salt. If the waste liquid contains platinum group metals, zinc scraps can be added to replace the recovery.
