In the modern world, platinum is a symbol of wellness, solidity, power, and prestige. It is used in heavy industry, space development, construction of aircrafts and precision instruments, medicine, dentistry, and, of course, in the field of jewelry.
What is platinum?
Let’s see, what do we know about platinum? It is a chemical element with the atomic number 78, and it has the symbol Pt. This is an extremely ductile metal that is more flexible than gold, copper, or silver. Therefore, this mineral doesn’t lose its toughness after remelting. It has such qualities as density and non-reactivity and is highly resistant to corrosion. This white metal is very stable at high temperatures up to 500C. If the temperature is higher than 500C, platinum forms PtO2, meaning oxygen develops. This can be removed thermally, however. The melting temperature of platinum is 1786C. It is heavier than gold and other metals.
Platinum is denser than gold and silver. If we compare these metals, silver’s density is 10.5 g/ml; gold’s density is 19.3 g/ml; platinum’s density is 21.4 g/ml.
This is a noble metal because of its durability, resistance to corrosion, and tolerance of high temperatures. Moreover, it is resistant to tarnish. That is why platinum is highly welcomed and used in jewelry.
This is a noble metal because of its durability, resistance to corrosion, and high temperatures. Moreover, it is resistant to tarnish. That is why platinum is highly welcomed and used in jewelry.
Why was this metal named Platinum?
As you know, the color of platinum is silverish-white. During human history, platinum occurred in pre-Columbian America. Spanish conquistadores named this metal “platino”, meaning “little silver”.
What is the history of platinum discovery?
This metal has a long history. People used it many centuries before Christmas, but they didn’t know what it was. There are small inclusions of platinum as well as rhodium, osmium, and palladium in gold deposits all over the world. As we know, platinum is higher density than gold; therefore, any purification attempts that ancient people did during metalwork couldn’t remove the white metal from the yellow one. That is why we can see a lot of things aged several centuries BC with platinum and gold alloy.
Platinum in Ancient Egypt
Archeologists have found things with traces of platinum in the Old Kingdom (2686-2181BC). Some golden items had platinum inclusions. The most famous artifact was the box of princess Shepenupet II found at Thebes. Its age is the 7th century BC. It is a copper box with hieroglyphs made with golden and platinum alloy.
Platinum usage in the pre-Columbian period
In the territory of modern Argentina, Ecuador, and Columbia, there were rich deposits of gold with platinum inclusions in rocks such as peridotites and pyroxenes, which are in the Andes Mountains. The natural erosion of rocks opened alluvial deposits that contained platiniferous gravels and sands, so Incas could find platinum under their feet. Therefore, gold-workers could create objects not only from gold but and from platinum too.
Incas realized that this silverish metal was very durable and solid. So, they created not only jewelry but domestic things, too. For example, archeologists found fish hooks, tweezers, awls, and needles. Among decorative things, they found idols, figurines, masks, pendants, etc.
Spanish period in South America
The history of platinum discovery is connected with the name of Antonio de Ulloa, the colonial administrator of Louisiana, scientist, astronomer, general of the navy, and author of several scientific works. From 1736 to 1744, Antonio was part of a scientific expedition in Ecuador. Their mission was to study the meridian arc. During this expedition, Antonio paid attention to the white metal mined by Native Americans. Before Ulloa, Spanish and French scientists who traveled to South America thought that platinum was the impurity of gold, and this metal was thrown away during the metalwork.
Antonio de Ulloa was the first scientist who examined platinum and wrote a scientific description of this noble metal (1748).
Another famous scientist whose name is connected to platinum discovery is the British doctor William Brownrigg. He received several samples of the mineral mined in Columbia. In 1750, he wrote a scientific work about this white metal and presented it to the Royal Society. William Brownrigg wrote that this was a new mineral and a new element that had unique qualities.
In 1752, the famous Swedish chemist Henrik Teofilus Scheffer examined this new metal and made a scientific survey of platinum, where he compared it to gold and named it “white gold” because, like gold, it was a precious metal with good resistance to corrosion.
Platinum in World War II
From 1920-1930, platinum was used in aircraft construction. Moreover, it was used in precision instrument construction. That is why, before World War II, the USA declared platinum a strategic metal to be used only in the military sphere. So, during the Second World War and some years after it, the usage of platinum in the jewelry industry was prohibited.
How is platinum mined?
Native platinum, when it is found in alluvial sands in grains or nuggets, is a very rare phenomenon. Mostly, this mineral is found as an alloy with such metals as gold, iron, copper, and nickel. Additionally, there are platinum-group metals like arsenides, tellurides, sulfides, and antimonides that we can find in copper and nickel deposits.
We can divide the platinum mining process into 2 types: mining of native platinum and mining of platinum ore, where this metal is an alloy with other minerals.
Mining of native platinum
This type of mining is very simple. It can be used in placer deposits, where platinum is in alluvial sand or gravel. This place can be in mining pits and in riverbeds. A miner scoops alluvial sand or gravel and washes it. The surrounding minerals wash out and the platinum grains sink to the bottom of the utensil. But remember that native platinum is a rare phenomenon.
Mining of platinum ore
This mining process consists of three stages:
- Extraction;
- Concentration;
- Refining.
This type of mining is very laborious and expensive. It could take from some months to half of a year. To produce a single ounce of platinum, miners need 11-12 tonnes of ore.
- The extraction is connected with using explosive packs that are put in the mountain and divide it into smaller parts. These parts are collected and transported to a factory. They are ground by machinery and mixed with chemicals or water (depending on the kind of ore). The role of these chemicals is to single out PGM (platinum group metals) from the ore.
The next process is flotation separation, during which air is blown in the mass. The aim of this action is to pick up the parts of PGM on the surface of the mass. The upper layer, which contains PGM, is collected and dried under chemical powder. One tonne of this mass could contain from 90 to 800 grams of PGM.
2. The process of concentration begins with heating the mass to the right temperature. The air which was blown earlier helps to remove iron and sulfur from the substance. One tonne of the mass may contain only 50 troy ounces of PGM.
3. The refining. Aqua regia is added to the substance in the next step. The aim is to remove chrome and nickel from the PGM mass. The mass is filtered to sort out the platinum. What is aqua regia? It is a mixture of hydrochloric acid and nitric acid. It received its name “the royal water” because these acids can dissolve gold, which is known as the royal metal.
Where are deposits of platinum in the modern world?
Platinum is a very scarce component of Earth’s crust. Its concentration is 0.005 ppm (parts per million). However, this metal exists in more abundant quantities in space. We can find it in the Moon. And meteorites that fall on the Earth’s surface contain platinum. So, maybe this metal has space provenience.
On Earth, we can find platinum in:
- Russia. They have reserves of 3900 metric tonnes;
- South Africa (Zimbabwe). Their reserves are the biggest. They have 63000 of metric tonnes;
- The USA. They have reserves of 900 metric tonnes;
- Canada. They have only 310 metric tonnes.
Why is platinum so expensive?
Platinum is an extremely rare metal. There are scarce deposits of this metal on Earth. For example, according to statistics of 2016, only 172 tonnes of this white metal were mined. As we know, it is more durable than gold; its resistance to corrosion is stronger than gold. The demand for platinum is huge. Besides jewelry, it is used in many important fields of human activity. That is why, according to ETF (exchange-traded funds) data, the cost of platinum per 1 gram is $30.73, cost per 1 ounce is $955, and cost per 1 kg is $30.729.