Aqua Regia Gold Refining Pilot Plant

This equipment is a complete gold refining system using the aqua regia process. It consists of two core modules: a dissolution tank unit on the left and a reduction tank unit on the right, corresponding to the entire process of gold dissolution, impurity removal, and reduction precipitation. This system is suitable for raw materials with a gold content of 90% or higher. If the gold content is lower than 90%, a powder mill is required for further refining. The system also includes a tail gas absorption device to achieve environmental protection and eliminate harmful gas emissions.

Aqua regia is a strongly acidic solution prepared by mixing concentrated nitric acid and concentrated sulfuric acid in a 1:3 volume ratio. It is an older method of gold extraction. In this process, gold mainly exists in liquid form, and is purified through the interconversion of solid and liquid phases. The process involves the reaction of gold with aqua regia, causing the gold to dissolve and form a chloroauric acid solution. After dissolution, a reducing agent (such as sodium sulfite or ferrous sulfate) is added to reduce the gold back to its metallic state and precipitate it out. The precipitated gold powder is then washed and smelted to finally obtain high-purity gold.

Process Flow:

Pre-treated gold-containing waste is added to the vertical reaction tank through the top inlet of the left-side unit. Aqua regia is injected into the reaction tank via pipeline, and stirring is started to prepare for the dissolution tank. After the gold dissolution tank (left-side core reaction tank), impurities form precipitates and remain in the reaction tank. The gold-containing filtrate is then transported to the right-side reduction tank. After the reaction is complete, the reaction solution is transported via pipeline to the filtration chamber of the right-side integrated unit. Impurities are filtered, and after precipitation, reduction and gold deposition (right-side integrated unit) are completed to finish the gold deposition process.

Equipment Advantages:

1. Modular Integration: Dissolution, impurity removal, and reduction are integrated, reducing material transfer losses and improving refining efficiency.
2. Sealed Design: The entire process is operated in a sealed manner, reducing the risk of aqua regia volatilization and NO harmful gas leakage, improving safety.
3. Automated Adaptation: Equipped with an electrical control module, it can precisely control temperature, stirring speed, and feed rate to ensure reaction stability.

ZJH MINERALS’ aqua regia gold refining equipment can effectively dissolve impurities in crude gold. Through subsequent reduction and precipitation steps, gold with extremely high purity can be obtained, typically reaching over 99.9%.