Impure Gold Refining

  1. Dissolved in the aqua regia using your selected dissolving agent.
  2. Once all of the metal is dissolved, add urea (a harmless chemical: CO(NH2)2) to remove any free nitrogen in the solution. With nitric-acid-based aqua regia, a large amount of urea is generally required. With MX3-based aqua regia, usually, only a pinch is required. The purpose of the area is to prevent gold from re-dissolving after it has been precipitated. If urea is not added and some free nitrogen remains dissolved in the solution, some gold may be re-dissolved.
  1. Add your selective precipitant to your solution. The gold will be selectively precipitated out of the solution. There are a variety of precipitants that can be used: Quadratic, sodium metabisulfite, sulphur dioxide gas, Storm Precipitant and ferrous sulphate are among the most common. Most of these precipitants produce very unpleasant fumes or odours and have other negative side effects. Some people prefer Quadratic Precipitant, since it’s odourless, fumeless, produces large particles that are easily rinsed, and has an unlimited shelf life. Regardless of the precipitant used, however, the resulting gold is typically from 99.95% to 99.99% pure.
The key to removing impurities is to get them to separate from the gold. Aqua regia is the name given to a mixture of nitric acid and hydrochloric acid. This combination is intensely powerful—more than the individual acids. In this process, the gold itself is dissolved and then precipitated after siphoning out the gold impurities. This method is typically used by Shruti refinery doing small to medium batches requiring 99.99% purity. This practice is commonly used because it is not time-consuming. It is effective at removing nearly all gold impurities with the upshot that if platinum is present, it doesn’t dissolve and can be separately refined.

Note: On request based on customer requirement we can produce 99.9995% Purity

Check your solution is checked with gold detection liquid to ensure that there are no precious metal losses. The gold detection test is sensitive to around 4 parts of gold per million parts of the solution–the maximum loss of metal left dissolved in the solution.

Looking for a First-Class Business Plan Consultant?

Contact Us

Copyright ©2019. All rights reserved.