Since ancient times, gold has captivated humanity with its alluring glow, scarcity, and resistance to corrosion. Highly prized as currency, art, and jewelry across civilizations, this precious metal has necessitated advancement in refining processes over the centuries to achieve ever higher purity levels. Today, sophisticated gold refining allows the production of 999.9 pure gold bullion from raw ore dug out of the earth’s crust, suitable for global financial markets and incorporation into advanced technology applications.
The transformation of crude, raw gold ore into glittering gold bullion is a multi-step refining process enclosing the core function of purification: removal of unwanted mineral and metal impurities from mined gold to achieve salable high karats of gold purity. At a high level, industrial gold refining involves chemical extraction of precious gold from ore, followed by smelting and electrolytic refinement to finalize pure 24-karat gold bullion bars.
Modern gold refining breakthroughs derive from series of refinements of historic processing techniques combined with cutting-edge technological advancements. By reviewing some of the key innovations shaping progress in gold refinement through the eras, we witness the compelling human quest to perfectly purify this most regal of metals prized for its majesty since the dawn of civilization.
Gold is refined to remove impurities that would interfere with its use and to achieve the desired purity for various applications. Refining transforms raw gold ore into pure gold bullion bars suitable for sale on financial markets.
Extracting Crude Gold
The first step is to extract crude gold from the rocky ore. This can be done using a technique called gold cyanidation, where the ore is washed over filter beds containing activated carbon. The carbon bonds to the gold, extracting it from the ore.
Smelting Crude Gold
Next, the extracted crude gold is smelted and melted to separate impurities and further concentrate the gold content. Smelting uses heat and chemical reducing agents to remove metal impurities from gold ore.
Refining Pure Gold
The pure gold extracted through smelting is refined through processes such as the Wohlwill or Miller process. In these processes, gold is placed in a chlorine-based acid solution to remove final impurities. What remains is 99.95% pure gold.
Casting Gold Bullion
Finally, the pure gold is cast into bars or bullion for sale. This finished gold bullion is now suitable for financial investment or incorporation into jewelry and industrial products. Its purity and origin are verified for legal, commercial sale.