As an expert in the field of electronics recycling and material recovery, I can provide you with a detailed process on how to extract gold from circuit boards. It's important to note that this process should only be conducted by trained professionals in a controlled environment due to the hazardous nature of the chemicals involved.

Safety First
Before we delve into the process, it is crucial to emphasize safety. The extraction of gold from circuit boards involves the use of strong acids and other chemicals that can be extremely dangerous if not handled properly. Always wear appropriate personal protective equipment (PPE) which includes gloves, safety goggles, a face shield, and a lab coat. Ensure that the area is well-ventilated and that you have access to an eyewash station and a safety shower.

**Method 1: Removing Gold Using Nitric Acid**

1. Preparation: Gather all the necessary equipment and materials. This includes circuit boards, a glass container, concentrated nitric acid, a glass rod for stirring, and a fume hood for ventilation.


2. Disassembly: Begin by disassembling the circuit boards to remove any components that do not contain gold. This step helps to minimize the amount of material you need to process and makes the extraction process more efficient.


3. Dissolving the Gold: Place the circuit boards in the glass container. Slowly pour the concentrated nitric acid into the container with the circuit boards. It's important to add the acid to the boards rather than the other way around to prevent a violent reaction.


4. Stirring: Use the glass rod to stir the mixture gently. This helps to ensure that the nitric acid comes into contact with all parts of the circuit board and dissolves the gold effectively.


5. Monitoring: Keep a close eye on the reaction. The gold will dissolve into the acid, forming a solution known as aqua regia, which is a mixture of nitric acid and hydrochloric acid.


6. Filtering: Once the gold has dissolved, carefully filter the mixture to separate the remaining circuit board material from the gold-containing solution.

7.
Precipitation: To recover the gold from the solution, you can add a reducing agent such as zinc or sodium metabisulfite. This will cause the gold to precipitate out of the solution and can be collected.

8.
Refining: The precipitated gold may still contain impurities. Further refining processes such as smelting may be necessary to obtain pure gold.

9.
Disposal: Properly dispose of all waste materials according to local regulations. The remaining chemicals and materials can be hazardous and should not be discarded carelessly.

10.
Cleanup: Clean all equipment thoroughly after the process to prevent contamination and ensure safety for future use.

Alternative Methods
While nitric acid is a common method for extracting gold, there are alternative methods that may be less hazardous. These can include using non-toxic chemicals or mechanical processes to separate the gold from the circuit boards.

Regulations and Legalities
It's important to be aware of the regulations and legalities surrounding the extraction of gold from electronic waste. Different countries have different laws regarding the handling and disposal of hazardous materials.

Conclusion
The extraction of gold from circuit boards is a complex process that requires knowledge, skill, and adherence to safety protocols. It's not a process to be undertaken lightly, and it's crucial to respect the environmental and health implications involved.

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Method 1 Removing Gold Using Nitric AcidGet protective gear. ... Purchase concentrated nitric acid. ... Put your circuit boards in a glass container. ... Pour the concentrated nitric acid into the glass container with the circuit boards. ... Stir the mixture using a glass rod until the contents become fluid in form.More items...read more >>