Gold Refining Plant

Aqua regia process

Gold (AU) not less than 65%.

Silver (AG) not more than 10%.

The process involves to dissolve gold in Aqua regia ( Acid+Water Mixture ).Silver will form Silver chloride precipitates, which will be filtered out.The filtered solution is treated with a Reducing agent Sodium Meta Bisulfite, and precipitates Gold, which is filtered, washed , dried and usually melted and granulated.

Std Refining capacities per Batch - 2kg, 5 kg, 10 kg, 20 kg, 25 kg.

Inquartation procedure

The most used refining technique is based on chemical method whereby the gold- bearing scrap is dissolved in aqua regia (HNO3 + HCl). The aqua regia refining technique efficiently works with alloys that respect the contents of silver less then 10%.

The silver percentage in the alloy represents a critical value to be considered in order to use the aqua regia refining technique. A high silver concentration, indeed, may block the reaction due to the exceeded amount of AgCl formed during the chemical attack.
 An alternative method for gold refining applied to high silver content alloys is the “inquartation procedure. Inquartation involves initially diluting the gold in the refinable material to about 25% (literally ‘quartering’ the gold) by melting with the appropriate addition of copper or silver, then treating with nitric acid. The acid will dissolve the silver and base metals, leaving behind the gold. The acid treatment is known as parting as it ‘parts’ (separates) the gold from the silver and base metals. Dilution of the gold content is necessary to ensure that the nitric acid can readily attack and dissolve the base metals and silver, some of which may be otherwise masked by the gold.

Std Refining capacities per Batch - 5 kg, 20 kg OUTPUT OF GOLD - 999,5/1000


Epoxy quoted structure and Polypropylene (PP) panelling. Staircase , handrail, and platform.

  • N. 02 graduated tanks with loading system for acids.
  • N. 01 Glass reactor heated by steam, complete with condensers
  • N.01 Polypropylene tank lid and system for loading and unloading acids
  • N. 01 PP loading basket for grains
  • N. 01 Borosilicate glass vessel. for the Au precipitation, complete of air stirrer system, redox probe for redox potential reading
  • N. 01 PP Trolley Filter unit for AgCl filtration complete of suction system and diaphragm pump
  • N. 01 PP Trolley Filter unit for Au filtering, complete of suction system and diaphragm pump
  • N. 02 Heat exchangers (condensers) DN 200 mm N. 02 Diaphragm pumps
  • N. 01 suitable Hot water circulator and control system
  • N. 01 Water chilling unit 220 V 2.400 W
  • N. 01 Air pump control distribution panel
  • N. 01 Electric board


Granular Raw material is reacted with Nitric acid, dissolving the silver content, which is then seperated and precipitated out by a reducing agent. This precipitated metal is enriched silver which is washed and taken for electroytic refining to achieve highest purity


Std Refining capacities per Batch - 20 kg, 50 kg , 100 kgs

Other process in refining

Electrolytic refining processes in Gold and Silver refining, however we endeavour to offer the complete state of the art processes.




The plant is composed of two sections: one is used to neutralize concentrated fumes (Nox) with an oxidizing solution, the second to neutralize fumes with an alkaline solution. The oxidizing section is composed of one scrubber where an acid solution is sprayed thought nozzles into the fume flow, and two scrubbers into which fumes are washed with an alkaline solution.

In details, the fumes scrubbing plant is composed of:

Oxidation section:

  • N. 01 Scrubber made in PP for acid fumes with right diameter complete of filling packs, sprayers and piping system – oxidizing section
  • N. 01 PP tank for the oxidation washing solution
  • N. 01 pump for circulation

Neutralization section:

Scrubbers made in PP with right diameter 900mm complete of filling packs, spray systems, distribution and re-distribution and piping system

  • N. 01 PP tank for the alkaline washing solution
  • N. 01 pumps
  • N. 01 Centrifugal blower or venturi


We undertake the installation, and process commissioning, training of the precious metal refining plant.