🔬Gold is trapped within an alloy of base metals and silver, which is dissolved using hot dilute nitric acid.
🌟The gold sponge is dissolved in aqua regia, resulting in a solution that contains gold.
⚗️Sodium metabisulfite is added to the solution, causing the gold to precipitate out and form solid particles.
🔥The reaction is exothermic and causes the solution to heat up significantly.
🔐The gold particles are filtered and washed to remove impurities, resulting in pure gold.
What is aqua regia?
—Aqua regia is a mixture of nitric acid and hydrochloric acid. It is used to dissolve noble metals like gold and platinum.
Why is sodium metabisulfite used?
—Sodium metabisulfite is used to precipitate gold out of solution because it reacts with the gold ions, causing them to form solid particles.
What happens if the temperature gets too hot during the reaction?
—If the temperature gets too hot, it can cause the gold to stick to the edge of the glass, making it difficult to separate from the solution.
How is the purity of the refined gold ensured?
—The gold particles are filtered and washed to remove any remaining impurities, resulting in pure gold.
Can this process be used to refine other metals?
—Yes, similar processes can be used to refine other precious metals such as silver and platinum.
00:01Introduction to the gold refining process and the use of sodium metabisulfite.
15:19The gold begins to precipitate out of solution, forming solid particles.
23:06The first solution is successfully refined, with all traces of gold removed.
24:09The second solution is refined, resulting in pure gold particles.
