Extraction of precious metals from waste slag

Extraction of precious metals from waste slag

With the acceleration of urbanization, the amount of garbage generated is also constantly increasing. Waste slag is the residue of Incineration, which is usually regarded as waste. However, garbage slag contains a large amount of precious metals, such as gold, silver, platinum, etc. If these precious metals can be effectively extracted, it will have dual benefits for the environment and economy. This article will introduce the methods and steps for extracting precious metals from waste slag.

1、 Precious metals in waste slag

Garbage slag refers to the solid matter remaining after Incineration. The precious metals contained in waste slag mainly include gold, silver, platinum, etc. Most of these precious metals come from electronic waste, jewelry, coins, and other items in the garbage. According to statistics, each ton of waste slag contains approximately 0.3 grams of gold, 1.5 grams of silver, and 0.01 grams of platinum.

2、 Method for extracting precious metals from waste slag

There are two main methods for extracting precious metals from waste slag: chemical method and physical method.

1. Chemical method

The chemical method involves dissolving precious metals in waste slag into chemical reagents, and then separating the precious metals through chemical reactions. The advantage of chemical method is that it can simultaneously extract multiple precious metals, but the disadvantage is that it requires a large amount of chemical reagents and causes significant environmental pollution.

2. Physical method

The physical method is to separate precious metals from waste slag through physical means. The commonly used physical methods include gravity separation, magnetic separation, flotation, etc. The advantage of physical method is that it causes less environmental pollution, but the disadvantage is that it can only separate a single precious metal.

3、 Steps for extracting precious metals from waste slag

The steps for extracting precious metals from waste slag mainly include the following aspects:

1. Pre treatment of garbage and slag

The waste slag contains a large amount of impurities and requires pre-treatment. The pre-treatment methods include screening, magnetic separation, flotation, etc.

2. Separation of precious metals

Perform corresponding operations based on different separation methods. The chemical method requires dissolving waste slag in chemical reagents, and then separating precious metals through chemical reactions; The physical method requires the use of corresponding equipment for separation.

3. Purification of precious metals

Purify the separated precious metals. The methods of purification include electrolysis, chemical reduction, etc.

4. Recycling of precious metals

The purified precious metals can be recycled and reused or sold.

4、 Conclusion

Garbage slag contains a large amount of precious metals. If these precious metals can be effectively extracted, it will have dual benefits for the environment and economy. The methods for extracting precious metals from waste slag mainly include chemical and physical methods, and different methods are selected according to different situations. The steps of extracting precious metals mainly include pre-treatment of waste slag, separation of precious metals, purification of precious metals, and recovery of precious metals. In practical operation, adjustments and improvements need to be made according to specific circumstances to achieve the best results.

Extraction of precious metals from waste slag