How to Extract Gold from Pyrite?

Pyrite, more commonly known as fool’s gold, is an iron sulfide mineral that crystalline structure can make it appear very similar to real gold. Though pyrite contains no real gold, it can contain trace amounts of the precious metal. There are a few different ways to attempt to extract the small amounts of real gold that may be trapped within iron pyrite.

Method 1 – Roasting

One of the easiest methods for extracting gold from pyrite involves roasting the pyrite in order to oxidize the sulfur and separate the iron from the real gold. First, obtain a sample of pyrite from which you will extract gold and crush it into a fine powder using a metal rod or pestle and mortar. Take the finely crushed pyrite and roast it in an oven at high temperatures between 950 to 1100°C, for about 30 to 60 minutes.

As it heats, the sulfur in the pyrite will begin to oxidize and separate from the iron. The oxygen in the air will react with the sulfur, forming sulfur dioxide gas which will bubble up and out of the oven. This roasting process will melt the iron in the pyrite into a slag that can be easily separated from the roasted pyrite ore.

After roasting, allow the pyrite to cool, then separate the iron oxide slag material from the remainder of the roasted ore by sieving and hand picking or using a magnet. You should be left with small amounts of gold mixed within the roasted pyrite ore. The gold can then be chemically extracted and refined to pure 24k gold.

Method 2 – Chemical Extraction

Another method for getting gold from pyrite involves brute force chemical extraction by dissolving the telluride minerals present in the pyrite using various oxidizing chemicals.

Begin by roasting and crushing the pyrite ore into a powder as outlined in the roasting method above. Then take the roasted pyrite powder and mix it in a solution of hydrochloric acid and nitric acid in a ratio of 3 parts HCL to 1 part HNO3. Let the pyrite sit submerged in this solution for 1-2 days.

The nitric acid will attack and dissolve out most of the metals like iron, gold, copper, zinc present in the pyrite. Filter the acid solution through cloth or paper filters to separate the dissolved metals and retrieve the undissolved ore chunks. Treat the filtered solution with a reducing agent like sodium metabisulfite, ferrous sulfate or oxalic acid to selectively precipitate out the gold.

The gold should form into black powdery precipitate at the bottom of the solution vessel that can be further refined to pure metallic gold. This chemical extraction method provides a much purer source of gold from the pyrite ore than simple roasting, though can involve the use of more complex chemistry procedures.

In summary, there are a couple methods available to attempt extraction of the small amounts of gold potentially present in pyrite ore sources. Roasting the pyrite at high temps allows the sulfur present to oxidize and separate from iron, leaving small bits of gold behind that can be melted out. Using a chemical extraction with hydrochloric and nitric acid also provides a way to dissolve out additional minerals like copper, zinc, and gold from the pyrite ore. Both methods allow prospectors to possibly extract gold from fool’s gold pyrite sources.