China is the largest storage country for tungsten, which is more resistant to high temperature than rhenium. Why is rhenium used in aero-engine blades?
The world's largest reservoir of tungsten is China
Although there are many types of rock, tungsten is found in most rocks, although the actual amount of tungsten present in rocks is very small. Specifically, tungsten is widely distributed in the earth's crust, but only about 0.001% of it. So it's very difficult to extract it from all kinds of rocks, so the purity and yield of tungsten depends a lot on the level of technology.
As we all know, metals are divided into non-ferrous metals and ferrous metals. For example, tungsten is one of the non-ferrous metals. After smelting, tungsten will appear silver white. I do not know how many people know, in fact, our country is the world's largest reserves in the country. For now, at least, China is the world's largest exporter of tungsten, both in terms of annual production.
The metal with the highest melting point is tungsten, with rhenium coming in third!
There are many kinds of metals in nature, we usually call those rare metals with high melting point refractory metals, in addition to tungsten, niobium, vanadium, tantalum, zirconium, rhenium and hafnium are included in this category, they have a common property is good corrosion resistance, and has the characteristics of high hardness and high melting point. Tungsten, for example, has a melting point of more than 1650 degrees Celsius, and a temperature of more than 1,000 degrees Celsius is needed for the oxide to evaporate.
Rhenium, a rare metal that was only discovered in 1925, is often extracted from flue gas (which must contain molybdenum), and 40 to 50 tons of rhenium are produced annually in countries such as the United States and Chile. Although rhenium has the highest boiling point of any metal, it does not melt as high as tungsten, and it can resist the corrosive effects of even aqua regia, sulfuric acid, and hydrochloric acid at standard temperatures and pressures.
Rhenium is only used in engine blades?
First of all, the price of rhenium is not cheap, which is why in practical applications, a lot of time are used to contain the material of rhenium alloys, and all the most widely used alloys are molybdenum rhenium and tungsten-rhenium, and have good plasticity and high temperature resistance. To be more specific, the proportion of rhenium in tungsten to rhenium ranges from about 10 to 26 percent, while the proportion of rhenium in molybdenum to rhenium fluctuates as much as 11 to 50 percent.
In other words, rhenium is not limited to engine blades, as turbine blades, jet combustion chambers, rocket engines, high-efficiency jet engines, and exhaust nozzles are likely to be made of nickel-rhenium superalloy. It's no exaggeration to say that many of the diamonds that people wear are not as difficult to get as rhenium, which enhances tungsten's physical properties.
Tungsten was found earlier than rhenium and can be recycled!
A Swedish chemist by the name of Scheele had discovered tungsten in 1781, and in 1900, broken tungsten lamps made their first official appearance at the Paris World's Fair. In the application process of tungsten, we not only enjoy the convenience and efficiency brought by the progress of science and technology, but also effectively improve the utilization of resources.
Globally, half of the use of tungsten is in high-quality steel, and while things like tungsten light bulbs were common in the past, the actual use of tungsten is only about 10%.In objective terms, tungsten is much more widely used than rhenium, not only involving aerospace, transportation and electronics, but also used in construction, light industry and chemical industry.
Some people may say, since the rare metals tungsten and rhenium are not in the same order of magnitude, why have these substances been found for so many years without use of light? Actually, this question is easy to answer because the rarer the material in the rock, the harder it is to extract it from the rock. And unlike oil and other substances, tungsten and rhenium have the advantage of being reusable in many cases and are generally not altered in their current state, even though their natural reserves are not as large.
As everybody knows, the interior of the earth is composed of three parts, and these rare material storage place is mainly the earth's crust, but from the point of existing data, the entire although there are more than six hundred about ten thousand tons of tungsten in the crust, but can be mined human dimension is less than three hundred tons, and the territory of China's tungsten reserves is as high as more than five hundred, ten thousand tons, Among them, Henan, Jiangxi and Hunan are the top three provinces with tungsten reserves.
Of course, tungsten, which has a higher melting point, is also relatively heavier, so why do you have to weigh your big luggage when you're on a flight? Whether it is a car running on the ground or a plane flying in the sky, its own weight will affect its normal operation, so the car and the plane can not be overloaded. In addition, tungsten is relatively fragile, and heat resistance does not equal the maximum melting point, so some aircraft will use tungsten and others will use rhenium, depending on the actual situation.
