Occurring naturally in the alluvial sands of various rivers, there is little evidence of its use by ancient people, however, the metal was used by pre-Columbian Americans near modern-day Esmeraldas, Ecuador, to produce artifacts in a white gold-platinum alloy. The first European reference to platinum appears in 1557, described by the Italian humanist Julius Caesar Scaliger as a metal “which no fire nor any Spanish artifice has yet been able to liquefy.”
ANTONIO DE ULLOA, CREDITED WITH DISCOVERING PLATINUM
When Charles Wood, a British metallurgist, found various samples of Colombian platinum in Jamaica in 1741, he sent them to William Brownrigg for further investigation. At the same time, Antonio de Ulloa, also credited with the discovery of platinum, returned to Spain after 8 years, from the French Geodesic Mission in 1746. Brownrigg presented a detailed account of the metal to the Royal Society in 1750, mentioning that he had seen no mention of it in any previous accounts of known minerals after studying the platinum sent to him by Wood. Torbern Bergman, Jons Jakob Berzelius, William Lewis, and Pierre Macquer were amongst other chemists across Europe who began studying platinum. In 1752, Henrik Scheffer published a detailed scientific description of the metal, in which he referred to it as ‘white gold’, including an account of how he succeeded in fusing platinum ore with the aid of arsenic. Scheffer also found platinum to be less pliable than gold, but with similar resistance to corrosion. Carl von Sickingen, during his platinum research in 1772, succeeded in making malleable platinum by alloying it with gold while Franz Karl Achard made the first platinum crucible in 1784.
$1 Million Dollars of Platinum in 1cm Cubes
In 1786, Charles III of Spain provided a library and laboratory to Pierre-Francois Chabaneau to aid in his research of platinum. Chabaneau removed impurities from the ore, including gold, mercury, lead, copper, and iron, leading him to believe the result to be of elemental origin, an incorrect assumption due to the fact that the ore still contained the yet-undiscovered platinum group metals. Confused by varying malleability of the ore, Chabaneau finally succeeded in producing 23 kilograms of pure, malleable platinum by hammering and compressing the sponge form while white-hot. While a platinum-iridium ore was malleable, a platinum-osmium ore was volatile by comparison. Understanding the value of this new metal, Chabeneau started a business with Joaquin Cabezas producing platinum ingots and utensils, starting what is today termed the ‘platinum age’ in Spain.
Native Platinum Nuggets
Separating platinum in its molten state from the ore involves the use of an electromagnet because platinum is non-magnetic. Platinum also has a higher melting point than most other substances consequently, many impurities can be burned-off or melted away. Because platinum is resistant to hydrochloric and sulfuric acids which readily attacks other substances, metal impurities can be removed from the ore by dissolving the surplus metals in an acid bath. Another effective separation method includes aqua regia, in which palladium, gold and platinum are dissolved, while osmium, iridium, ruthenium and rhodium stay unreacted.