Gold recovery from mines/re-used gold/recovery gold

Gold is something that has been the fascination of civilizations of thousands of years. Since ancient times in the form of coins and royal ornaments, up to the current times of investment bullion and jewellery, gold has been one of the most valuable and widely traded metals in the world. However, between the time a gold ornament is mined and the moment it is displayed in a jewellery shop, it passes through a lengthy and complicated process of refining, production and finally recycling. This is a process that can make us value not only the worth of gold but also the science and industrial aspect of it.

This blog discusses the entire lifecycle of gold- starting at the mines and then refining it into bullions, making jewellery and then recycling the old gold to new uses.

Explore our full collection of elegant gold nose pins and nose rings.

Part 1: Gold Mining and Refinery

1.1 Mining Process: Exploration to Ore Mining

The gold trip starts somewhere deep in the earth. The mining of gold begins with exploration, and the geologists determine the regions that have the gold-bearing rocks referred to as ore deposits. Mining companies are using other sophisticated methods like geological mapping, drilling and chemical analysis to identify whether a location has economically viable deposits of gold.

After a deposit has been confirmed, the extraction process commences. Megamines employ the use of open-pit or underground mining techniques in extracting gold ore out of the earth.

Following the extraction, the ore is taken to the processing plants where it is crushed and ground. The rocks are then broken down into smaller sizes by heavy machinery, which breaks them down to fine powder.

This ore is then dissolved in water to produce a slurry that is critical in the chemical extraction process that will occur subsequently.

1.2 Chemical Leaching: The Primary Mode of Gold Mining

Cyanide leaching is the most commonly used technique of obtaining gold by ore and it has recovered almost 80 percent of the world gold production.

In this process:

•  A mixture of a cyanide solution and the slurry of powdered ore is formed.

•  The ore is reacted with cyanide which dissolves the gold particles and forms a gold-cyanide complex.

•  The gold is then precipitated or adsorbed using carbon to separate the gold and the solution once dissolved.

The gold is not pure yet, the material recovered, still has impurities and other metals. This semi-purified product is then forwarded to the refineries where additional processing is done.

Othakal Nose Pins Explained: Kerala’s Classic Single Stone Diamond Gold Design

1.3 Smelting and Refining

Smelting is the second step and the extracted gold concentrate is heated to very high temperatures of up to 1200 C or more.

During smelting:

• The substance melts and dissociates.

• The impurities mix with the flux materials and create slag, which is deposited on the topmost and is extracted.

• The rest of the metal is solidified into gold doré bars, usually with 90 to 95 per cent purity of gold.

Dore bars are then shipped to refineries that are specialized to carry out additional purification.

Rand Refinery in South Africa is one of the most famous refineries in the world. It was founded in 1920 and is one of the biggest integrated precious metals refining and smelting complexes in the world.

At refineries, gold is refined electrolytically, in which electricity and chemical solutions are used to eliminate impurities. This is done to give highly pure gold of 99.99% purity.

1.4 Final Output: Gold Bullion

The gold, when purified, is beaten into the different commercial modes:

• Gold bullion bars

• Gold granules

• Gold powder

These are high-quality products that are exported to the world market and are invested in, jewellery production, electronics and other sectors.

Red and White Himachali Nose Pins: The Cultural Meaning Behind These Traditional Designs

Popular denominations of bullion are:

• 100 grams

• 1 kilogram (most popular for jewellers’ consumption. It can be easily used in factories and is easier to cut)

• 12.5 kilograms (standard international bar – used for storage)

Smaller denominations are simpler to trade whereas larger bars are prevalent with banks and bullion markets.

Myth Busting: Does the Quality of Gold Change by Country?

Another gold market myth is that some of the gold produced in some countries is superior e.g. Switzerland or Dubai.

Actually, geography is not important in the purity of gold, but refining technology.

When it attains levels like: then Gold is said to be pure:

•  99.50% purity

•  99.99% purity

The high purity levels are realized by sophisticated refining techniques such as the electrolytic refining, irrespective of the nation.

The other practicality of the gold trade is that there are areas, especially in Africa, whose regulatory systems are weaker. Due to this, gold mined there is usually sold via trading blocs like Dubai where the gold can be refined and certified to be added to the world markets.

Rajasthani Gold Nose Pin Designs: A Perfect Blend of Heritage and Style

Part 2: Gold making out of Refinery Gold

When gold is refined into bullion, it goes to jewellery production units.

Nevertheless, raw gold is not applicable in the production of jewellery.

2.1 Alloying: Creating K-Gold

Gold in its purest form is very tender and malleable. On one hand this property allows easy shaping, but on the other hand, it is not applicable in the daily jewellery as it is easy to bend or scratch.

Alloying of gold or mixing it with other metals is done to make it last longer.

Common alloy metals include:

• Copper 

• Silver

• Palladium (for making white gold)

• Zinc (used mostly for soldering purposes to reduce the melting point or making the gold softer, and is also used to make lower-carat jewellery)

The melting points for all karats of gold are as follows:

*Note: The exact melting point within any given range depends on the precise alloy formula

Colour also depends on different alloys and this leads to yellow gold, white gold or rose gold.

All about gold/diamond nose jewellery price

2.2 Casting and Fabrication

After producing the required gold mix, the jewellery production process starts.

The casting techniques used to pour the alloy into molds are done when it is already molten. The raw shape of jewellery is then shaped after cooling.

Next steps include:

• Stone setting (of diamonds or gemstones)

• Intensive carving and cutting.

• Polishing and finishing

In the polishing and finishing, the jewellery surface is polished and treated in order to obtain its final shine.

Part 3: Recovery of Gold through Old Jewellery

Gold possesses a rare quality over most metals, in that, it can be recycled many times without degradation in its chemical characteristics.

3.1 Collection and Assessment

Jewellery that is worn out or damaged usually finds its way back into the market as scrap gold.

The recycling process starts with:

• Collection of old jewellery

• Sorting by purity (22K, 18K, 14K, and 9K)

• Removing gemstones

• Recording initial weight

The metal is then processed but first, stones are appreciated as an independent product.

How Gold Travels From Mining to Jewelry: Pricing Determination and Caratage Explained

3.2 Mechanical Processing

Next, the jewellery is:

• Cut into smaller pieces

• Melting the jewellery 

• Granules making

This mechanical treatment facilitates a gold refinery process.

3.3 Taking out Final Jewellery

• Granules for Acid treatment (using nitric acid) for gold extraction. Silver, copper, and other metals extracts into water due to the acid. Water turns blue. This treatment should be done twice to three times.

• Gold gets converted into fine powder form

• Filter the gold which is 24k purity.

Losses in the manufacturing

Small quantities of gold can be lost during jewellery production and recycling as a result of:

•  Pollution of dust during polishing and cutting.

•  Surface erosion during wear

•  Wastes left in melting machines.

•  Finishing through sieving and brushing.

These losses render it hard to recover fully.

Final Processing Methods

Refiners recover gold in scrap jewellery using several methods including:

Aqua Regia Method

The simplest one, in which gold is dissolved by means of a mixture of nitric and hydrochloric acid.

Borax or Melting Method

During melting, flux materials are used to separate gold and impurities.

Electrolytic Refining

Extracts high quality gold using recycled material.

Some traditional work can also be done with mercury, but nowadays is being replaced with modern facilities because of its environmental effects.

3.5 Gold Recovery Rate

Although technology is advanced, there is some loss that is bound to occur during the process of recycling.

Recycled gold is typically 99.5-99.99 percent pure.

The Circular Journey of Gold

The reason why gold is special is that it does not ever actually exit the economic system. Instead, it cyclically repeats itself:

• Gold mined on earth is refined into bullion, which is then made into jewellery, used and scraped, refined again to make new jewellery.

• This is a cyclical process that makes gold one of the most sustainable precious metals in the world.

Rose Gold Nose Pin Designs: The Perfect Blend of Tradition and Modern Style

Final Thoughts

From the discovery of gold in deep underground mines to the creation of exquisite jewellery, the process of gold is scientific and intriguing. Mining, refining, alloying and recycling illustrate the complexity of what people may seem to be a mere adornment.

Be it a gold bar in the vaults as an investment or a family heirloom of jewellery, all the grams of gold have their tales, perhaps they started their life thousands of miles below the surface and may well be still traveling centuries to come.