The borax method is a technique of artisanal gold mining, which uses

borax Borax is a salt (ionic compound), a hydrated borate of sodium, with chemical formula often written . It is a colorless crystalline solid, that dissolves in water to make a basic solution. It is commonly available in powder or granular form, ...

as a

flux Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface or substance. Flux is a concept in applied mathematics and vector calculus which has many applications to physics. For transport ph ...

to purify gold concentrates. By using borax, no

mercury Mercury commonly refers to: * Mercury (planet), the nearest planet to the Sun * Mercury (element), a metallic chemical element with the symbol Hg * Mercury (mythology), a Roman god Mercury or The Mercury may also refer to: Companies * Merc ...

flour is produced, hence gold recovery increases. (dead link 5 June 2018)

History

The borax method of gold extraction has been used by artisanal gold miners in the

Benguet Benguet (), officially the Province of Benguet ('';'' ; pag, Luyag/Probinsia na Benguet; ilo, Probinsia ti Benguet; ), is a landlocked province of the Philippines located in the southern tip of the Cordillera Administrative Region in the islan ...

area north of

Manila Manila ( , ; fil, Maynila, ), officially the City of Manila ( fil, Lungsod ng Maynila, ), is the capital of the Philippines, and its second-most populous city. It is highly urbanized and, as of 2019, was the world's most densely populate ...

in the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

for more than 30 years. Some believe it was in practice as early as the 1900s. The method is increasingly being seen as a safe alternative to the widespread use of toxic mercury in artisanal gold mining today. About 30% of the world's mercury emissions comes from small scale mining. Efforts are being made to revive the method and spread its use. As of 2012, around 15,000 artisanal gold miners in a small area of

Luzon Luzon (; ) is the largest and most populous island in the Philippines. Located in the northern portion of the Philippines archipelago, it is the economic and political center of the nation, being home to the country's capital city, Manila, as ...

, the main island in the northern portion of the Philippines, use this method exclusively. The mineral is inexpensive and easily available, and the miners have reportedly found that more gold is recovered through its use.

Chemistry

In contrast to the use of mercury (which relies on amalgamation of the gold to coalesce it and separate it from impurities) this method relies on borax's ability to lower all the minerals' melting points. Since the gold is usually the heaviest of these minerals, it allows for concentrating the gold on the bottom of the crucible. The process requires considerably less heat than conventional refining methods, which can be obtainable even in remote locations (using charcoal). After the ore is crushed into a fine powder, it's lightly panned to leave only the heaviest minerals in the pan. It's then thoroughly mixed by three times (by volume) as much of borax and a few drops of water. This mixture is then heated until the whole mixture is molten, after which molten droplets of gold collect on the bottom of the crucible.

References

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External links

Video
of the borax method Gold mining Chemical processes Metallurgical processes Borates

History

Chemistry

See also

References

External links