The Gold Production and Refining Process

With the state of the current economy, the world’s financial systems have come into the spotlight recently. As stocks have dropped and companies have become unstable, gold has also been a source of much attention as the price of gold has skyrocketed. People want to have a tangible indicator of wealth and nothing serves that purpose like gold.

Since earliest recorded history, gold has been the most highly prized precious metal. Its malleability, corrosion-resistance, and rarity, have made it a valuable commodity. But where does gold come from?

Gold is a chemical element found as nuggets or grains in veins or alluvial deposits in the earth. South Africa, the United States, and Australia are the world’s top three gold producing nations. Most gold in the U.S. is mined in open pit mines. Scientists use technology like satellite surveys and geochemistry to locate a gold ore deposit. The deposit is measured and the mine is carefully designed. Samples of the ore are then taken to measure the grade of the ore as well as its metallurgical properties.

The ore is then mined and separated into low grade ore and high grade ore. The low grade ore is dissolved and collected. The high grade ore is ground and pulverized into powder. That ore is then separated into three different processes, depending on the characteristics of the ore. Refractory ore containing carbon is roasted and burnt down to oxide ore. Oxide ore is sent to a leaching circuit where it is dissolved in cyanide. Sulfide refractory ore without carbon is oxidized in an autoclave to remove the gold from the minerals and then it is sent to a leaching circuit.

Once the leaching process is finished, the gold is collected out of the solution and onto activated carbon. It is then loaded into a vessel and the gold is chemically stripped from the carbon. Using chemical substitution called the electrolytic process, the gold is precipitated from the solution and it is finally in its pure form. This pure gold is then melted into bars called “dore” bars that contain up to 90% gold. These bars are then sent to precious metal refiners for further refining until the bars of gold are up to 99.9% pure gold.

There are two main methods for refining gold: the Wohlwill process and Miller process. After refining, these bars can then be kept and used in financial dealings or melted down and used in thousands of other applications like jewelry, watches, coins, dentistry, medicine, industry and many other applications.

Source by Art Gib

The Gold Production and Refining Process