Learn cesium metal features and application fields

Cesium metal overview  

The word "cesium" may sound strange to you.  In fact, cesium is a metallic element that can be used in everyday life, such as television sets -- it is used in photocells -- because of its valuable and excellent photoelectric properties, namely, the release of electrons when exposed to light.  The cesium metal is sprayed on the silver sheet to make a variety of photocells, which can be used in movies, television, photometers and many communication and automatic control equipment.  Photocell irradiation by light produces photocurrent, the stronger the light, the greater the photocurrent;  Using this characteristic, the photocell is installed in the steelmaking furnace, and the temperature in the furnace can be calculated and controlled by the difference of the brightness and shade of the flame and the amount of photocurrent formed. It plays the role of "eyes" in automatic control, so cesium has the title of metal with long "eyes".

Cesium metal granules properties 

Cesium, unlike what we think of as a metal, is softer than paraffin, the softest metal in nature;  It is also the second most fusible metal after mercury, with a melting point of only 28℃, lower than the body temperature.  Moreover, cesium is one of the most active metals in nature because of its extremely reactive nature.  These factors make cesium metal flammable and flammable when wet, so it is classified as a hazardous chemical.  If cesium is dropped into water, it can instantly ignite a rose-colored spark.  Soft, lively, magnificent and dangerous are the first impressions of cesium.

Because cesium is so active, it must be sealed in a glass tube to ensure isolation from air and water to be safe;  Cesium therefore needs to be kept in vacuum/inert gas glass ampoules (Ampul) and generally operated in glove boxes.

Cesium-137 is the number one cause of nuclear contamination  

Cesium itself is not radioactive, with a molecular weight of about 133. Cesium-133 naturally is a stable element, but other isotopes, such as cesium-137, are radioactive and deadly to the human body.  

In 1987, two thieves in Brazil stole a large lead canister containing cesium salts from a radiology institute. They dismantled the canister and sold it to a collection station for scrap. After the canister was dismantled, the contact transmission of the radioactive element resulted in various levels of radiation in the body of about 200 people in the town, and they died.  In fact, the cesium salt in a large lead tank is a capsule 5.1 centimeters in diameter and 4.8 centimeters in height. It is called a cesium bomb because of the color of cesium salt, which makes it a dark blue glowing object.

The biggest reason people talk about nuclear color change is also because of the presence of cesium-137.  Such as serious nuclear accidents, like Japan's fukushima level will be including cobalt 60 and iodine, iodine - 129-131, uranium - 235 and plutonium - 239, dozens of usual see radioactive substances released from the scene, but most of them are "short-lived", such as no pollution food has decay, only cesium, iodine, strontium, known as remote contamination three,  And the number one killer is cesium - 137: one is that it is in the environment migration speed is quite fast, 2 it is the chemistry of cesium potassium and constant elements in the human body is very close, after enters the body, will be like potassium widely distributed in the body fluid inside the cell, and involved in various physiological activities associated with potassium, side of human body cell and DNA indiscriminate destruction;  To make matters worse, radioactive cesium has a half-life of up to 30 years, making it a constant threat to food and food production.  

By comparison, the number two killer, radioactive iodine (mainly iodine-131), has a half-life of just eight days and its damage is concentrated in the thyroid gland, which is much less harmful when combined with the fact that iodine-131 causes and cures cancer.

Cesium metal is precious when it is scarce  

Cesium is rare in nature, and has no elemental form, mainly in the form of salt is distributed in small amounts and scattered in the land and sea.  There is about 1/100,000 cesium in seawater, more than 400 billion tons, but there is no technology to develop it.  The surface is mainly in the form of cesium garnet and lithium mica.  The grade of cesium in limica is very low and the development cost is high.  As an independent mineral of cesium, cesium garnet, cesium oxide (Cs₂O) content in 5% ~ 32%, is the main raw material for cesium extraction.  Cesium garnet is a colorless and transparent hard mineral with glassy luster, but the amount of ore kept in the world is rare, and the annual output of cesium is also less than kilograms.

Future popular "cesium" -- is an indispensable material in the field of environmental protection and science and technology, has a huge market space.

Cesium metal application fields 

As a rare mineral, cesium metal and cesium salt has been highly recognized by high-tech enterprises for its safety, environmental protection and high efficiency in industrial applications, and has been used on a large scale. It is irreplaceable in many industries and has broad prospects in the future.  Has been the United States, Japan and other western developed countries as a key mineral.  

1. Oil and gas drilling  

At present, cesium is the largest application field, mainly using cesium formate as petroleum finishing liquid.  Compared with the traditional solid drilling fluid, it has the obvious advantages of preventing bit dissolution, reducing the failure rate of sticking and being friendly to the environment.  

2. Catalyst

It is currently the second largest use of cesium.  The use of cesium sulfate in the production of industrial sulfuric acid can reduce SO₂ exhaust emissions, is the most promising catalyst.  

3. Atomic clocks  

Modern quartz oscillator to time, but the stability of quartz clock is not enough to measure the position of the fast moving spacecraft has a very big impact.  Atomic clocks combine quartz crystal oscillators with collections of atoms to achieve greater stability.

4. Magnetic fluid generator  

High thermal efficiency can be obtained by using cesium-containing compound as the material (conductor) of the MHD generator.  The total thermal efficiency of general nuclear power plants is 29% ~ 32%, but combined with MHD power generation can increase the total thermal efficiency of nuclear power plants to 55% ~ 66%.

5. Ion thrusters  

Ion thrusters can be widely used in satellite, spacecraft and other fields.  Using 1 kilogram of cesium in outer space produces 1,100 times more thrust than any other fuel and has about 150 times the range of today's solid or liquid fuels.  Moreover, ion-propelled engines are 10 to 15 percent lighter than conventional engines.  So cesium is also known as the "space age" metal.

6. Other areas  

Detectors and sensors.  Cesium iodide as scintillation material detector, widely used in port, dock, station safety detector, metal flaw detector, metal detector, deep well probe, etc.  At the same time, cesium iodide crystal is widely used as a photosensitive element in CCD digital imaging.  

At present, cesium market in catalyst and photoelectric devices and other traditional fields has maintained steady growth, has realized the jump from ten tons to thousands of tons, there is still a huge space in the future.  Take the oil and gas field as an example, a deep well needs about 500 tons, but this field is rarely applied in China at present.  In the field of magnetic fluid generator, the United States, Japan and other countries have included it in the national plan, and China is also actively committed to this aspect of research. A 600,000-kilowatt magnetic fluid power station needs to use about 3,175 tons of cesium carbonate every year, with considerable demand space.  

At the same time, as an indispensable element in the field of new technology, its three emerging areas of demand in the future, including atomic clocks in 5G field, ion propulsion engines for satellites, and storage materials for quantum technology, will also see a significant increase in demand in the next decade.