The gold refining process
Ensuring precious metals are refined by a reputable and accredited refinery can make all the difference for the producer and their business goals.
The basic overview is that a refinery receives raw material such as gold nuggets or doré from mining companies. This material is then heated to molten metal and chlorine gas injected to separate the gold from other metals impurities. Once separation has occurred, the gold is tested, also known as assaying, to determine the purity before it’s cast into bars.
A more detailed step-by-step process guide explains what we do here, specifically, at The Whiteline Gold Refinery in Zambia to ensure our partners receive the highest-quality and purity of gold.
1. Doré melting
The assay process starts here. The Melt House is where rough gold deposits are melted and electromagnetically stirred. Immersion dip sampling also takes place to extract representative samples from the mixed metal prior to the analysis stage.
2. Sampling
Five samples are then taken, with three sent to the laboratory and the other two retained for independent customer and umpire analysis.
3. Assaying
In one of the most advanced and best equipped precious metals assay laboratories in the whole of the southern hemisphere, you’ll find our highly trained team of chemists and technicians with more than 20 years’ combined experience in precious metals analysis between them.
Our bullion analysis relies on high accuracy micro balances. These balances record the weight to one-millionth of a gram, with the newest balance reading ten-millionth of a gram. The whole process is highly technical, skilled, and accurate.
In this part of the process there are two further steps:
- XRF screening takes place to determine the gold, silver and base metals.
- Once complete, fire assay is used to separate the base metals from the precious metals. This dual stream analysis is conducted by two separate analysts to ensure the final results provide the greatest accuracy possible and confirm we have obtained a truly representative sample of the melt.
Our assaying is so accurate that our gold analysis has been tested to be within 0.001 per cent for gold by the London Bullion Market Association (LBMA) – the global gold industry’s premier regulatory body.
It’s this level of accuracy, and uncompromising attention to detail, that producers need most. Ultimately, it’s this that gives you your greatest return.