It is not at all necessary to be a qualified chemist to get the gold contained in a huge number of radio components, although, of course, it is worth following the safety rules.
Instructions
Step 1
Check the technical data sheet of the part to find out what percentage of the gold content is in this product. You will need this to calculate the amount of reagents for obtaining gold and the reaction time. Please note: the data on the content of this metal, presented in the technical data sheets of parts, may not always correspond to reality. However, domestic radio components manufactured before 1989 always contain exactly the same amount of gold as indicated in the accompanying documents.
Step 2
Perform all work only in a ventilated area. Put on a lab coat and gloves.
Step 3
Prepare "aqua regia" (ratio of nitric acid to hydrochloric acid 3: 1). Heat this mixture to 70-80 ° C. Take gold blanks and dissolve them in this mixture. If you have a large number of blanks, then lower them into this mixture in small portions (1-3 g each) and only after dissolving the previous ones.
Step 4
Since the radio components contain a large amount of copper, the solution obtained in this way will have a dark green color. Evaporate the solution until its volume is reduced by several times.
Step 5
In addition to copper, there is, of course, iron in the details. Pour a few milliliters of hydrochloric acid into the solution so that the brown precipitate caused by the precipitation of iron salts dissolves.
Step 6
Pour some ordinary table salt into the solution (at the rate of 0.2 g of salt per 10 ml of solution). Continue to slowly heat the container with the solution up to the "wet salts". Then add some boiling water to the container and continue to evaporate. Then pour in a few milliliters of hydrochloric acid and continue heating. This procedure is necessary in order to remove the remains of nitric acid from the solution in order to avoid loss of gold.
Step 7
Add 0.5% hydroquinone solution (1 ml of substance per 100 ml of solution). Soak the resulting mixture for 4 hours, remembering to stir it occasionally. Filter the precipitate using a thick filter, rinse with water (with a small addition of hydrochloric acid), dry and remelt at a temperature of at least 1100 ° C under a layer of borax (to protect the gold from evaporation). Refrigerate and separate the gold from the frozen borax lumps.
