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When it comes to precious metals, most of the first things that come to people's minds are gold, silver, and at most platinum, which are well-known because they have been found to be used for a long time and are relatively common in the market.
In fact, there is much more precious metal in nature than these, there is a precious metal, the value of about 10 times that of gold, the world's current proven reserves are only 3,000 tons, this precious metal is rhodium.
What is rhodium? Is it so expensive just because it has few reserves? What are the uses of rhodium?
Rhodium is a hard and rare metal, from the appearance, exudes a silvery-white metallic luster, it belongs to the platinum group elements, and platinum group metals such as platinum, palladium, osmium, iridium, ruthenium and other properties are somewhat similar.
In 1803, the British scientist William Hebernard discovered a beautiful red solution in the process of extracting pure platinum metal, and obtained some rose-red crystals from it.
After extracting these crystals, he obtained an unknown metal, which William named "rhodium", which means rose in ancient Greek, which is the precious metal rhodium.
In terms of physical properties, rhodium has the characteristics of high density, high hardness, high temperature resistance and high reflectivity.
In particular, its density is as high as 12.41 g/cm³, which is the highest density of all substances, so it also has a high hardness, which can reach 6 to 7 on the Mohs scale, and is very wear-resistant.
Rhodium has superior high temperature resistance, with a melting point of 1964 °C and a boiling point of 3695 °C.
For light from the outside world, rhodium has a refractive index of up to 1.792, which makes it always look shiny and shiny, with a unique metallic luster.
The most prominent feature of rhodium's chemical properties is its corrosion resistance, whether it is oxygen in the air, water, or various highly corrosive acids and alkalis, there is nothing to be done with it.
Aqua regia, which is a mixture of concentrated hydrochloric acid and concentrated nitric acid, can corrode almost all substances on the earth, but in front of rhodium, it is like a glass of plain boiled water, not only that, but after soaking in aqua regia, the luster of rhodium is brighter.
Such characteristics make rhodium useful in many industrial fields, so its value is also very high.
The gold on the market is about three or four hundred yuan a gram, and the highest is about 500 yuan, while the price of rhodium once reached 4,000 yuan per gram, and it was more than 3,000 yuan when it was low, about 10 times that of gold.
Even though it is so expensive, rhodium has become a scramble for purchases in countries around the world, simply because the reserves of this metal on earth are so small, and its use is very important.
Worldwide, rhodium is mainly found in three countries: Zimbabwe, Russia and South Africa.
In particular, South Africa is currently the country with the highest production of rhodium metal, accounting for 80% of the world's annual output, and the country's Bushwell platinum mine is a world-famous producer of rhodium metal.
Even so, South Africa produces only about 10 to 15 tonnes of rhodium a year, while Russia and Zimbabwe produce at most three or five tonnes a year, which is already a high output.
It can be seen that rhodium is a very rare metal in the world, and for the mainland, rhodium deposits are mainly distributed in Gansu, Yunnan, Sichuan and Heilongjiang.
The reserves of these four provinces account for about 95% of the national reserves of the mainland, of which Gansu Province accounts for 57.5% of the reserves.
In addition to the scarcity of reserves, the extraction of rhodium is also very difficult, and usually, rhodium metal coexists with other platinum group elements.
An ore may contain platinum, iridium, ruthenium and other elements, and the content of rhodium is very low, it is not easy to extract a few micrograms of a whole piece of ore.
For this reason, the extraction of rhodium requires fine beneficiation and separation by complex physical and chemical methods, such as flotation, magnetic separation and extraction.
The melting point of rhodium metal is very high, and in the process of extracting ore, it is necessary to use high-temperature smelting technology, which requires a lot of energy to achieve, which virtually increases the cost of extraction.
In addition, the distribution of rhodium metal deposits is very complex, and it is not easy to accurately explore the location of rhodium ore, which requires exploration workers to use geophysical exploration, chemical analysis and a variety of geological exploration techniques, which will consume a lot of manpower and material resources.
All these factors have also raised the price of rhodium from one aspect, after all, scarcity is expensive, and at the same time, for some industrial fields, rhodium is an important raw material that cannot be obtained, so even if it is not easy to obtain, many countries will compete to develop and buy.
Because rhodium has very stable properties, it has a wide range of uses in some industrial manufacturing fields, known as "industrial vitamins".
In the automotive industry, the use of automobile exhaust catalysts can reduce automobile nitrogen oxide emissions, and rhodium is an important raw material for making catalysts, with the rapid development of the automotive industry in mainland China, the demand for rhodium is growing.
Rhodium metal can play an important role in the preparation of superalloys due to its high temperature resistance, and is often used in the manufacture of jet engine parts, spacecraft and aircraft parts, and high-temperature melting equipment.
Aerospace parts made of rhodium are not affected by various extreme environments and can work stably and continuously, which is of great significance for the production of aerospace science and technology products in the mainland.
Rhodium metal can hydrogenate with hydrogen in a specific state, so it is of great help to the manufacture of some spices, organic chemicals and pharmaceutical intermediates, and rhodium metal can be used as a catalyst raw material.
The compactness of rhodium makes it have low resistance and good electrical thin film properties, which is crucial for the electronics industry, and rhodium will be present in the manufacture of electronic components such as inductors, resistors, and thin film resistive components.
With its high hardness and corrosion resistance, rhodium metal has also become an important material for the manufacture of high-end precision instruments, and contacts, brushes and electrical joints made of rhodium metal have excellent performance and are widely used in the field of electrical equipment.
In addition, the glass industry, steel nibs, alloy products, jewelry products and other industrial fields, there is a place for rhodium metal, and its wide range of uses makes it a "sweet spot" in industrial manufacturing.
In 2019, the mainland's demand for platinum metals has reached 694.10 tons, and the demand has increased unabated since then.
At present, the proven reserves of rhodium metal in the mainland are about 401 tons, which is not much, which requires that waste be avoided as much as possible when mining, and it also requires the mainland to make continuous progress in mining technology to narrow the gap with the developed countries in the world.
Resources:
[1] Jinan Times: "Selling "Rhodium" is Addictive?100 Kilograms Earned 240 Million, This Company Plans to Sell Another 200 Kilograms"
[2] Daily Economic News: "Stunned! It is more bullish than gold, soaring more than 20 times in 4 years, and the price has hit a new high recently, what is the reason?"