DID YOU KNOW?In the family of the periodic table, there is an element known as the source of blue magic, revealing unknown mysterious powers!It is the mysterious element of cobalt, which has attracted the attention of scientists with its unique personality. As a wonderful element, cobalt plays an irreplaceable role in our lives, from the vivid blue pigment to the core ingredient of eco-friendly batteries. Its magical power even extends to the medical field, bringing good news to mankind. Today, let's explore the mysterious world of cobalt and feel its endless charm!
The discovery of cobalt can be traced back to around 2000 B.C., when the ancient Egyptians discovered a peculiar blue pigment called it "Egyptian blue", which they fused with glass to create beautiful blue jewelry. How this pigment is made is still a mystery to this day, and the ancient Egyptians were so tight-lipped about the recipe that they even buried the secret recipe deep in the pyramids.
However, it was not until the 18th century that a clear understanding of cobalt was reached. In 1753, the Swedish chemist G. Brandt isolated the light rose-colored gray metal, which is the purest metal, cobalt, from pyrocatonite. As a result, Brant is considered to be the discoverer of cobalt. In 1780, the Swedish chemist Bergman made pure cobalt and determined that cobalt was a metallic element. Lavoisier included it for the first time in the periodic table in 1789.
Cobalt is an important transition metal element with a wide range of applications. Here are a few of the main application areas of cobalt:
Batteries: Cobalt is an indispensable ingredient in lithium-ion batteries and nickel-metal hydride batteries. In these batteries, cobalt is used to make anodes and cathodes, providing high energy density and long life. Currently, a large number of electric vehicles, mobile phones, and portable electronic devices use cobalt batteries.
Superalloy: Cobalt alloy is a material with high strength and good heat resistance, which is widely used in aerospace, energy, and chemical industries. Cobalt alloys are commonly used in the manufacture of turbine engine blades, combustion chamber components, rocket nozzles, and more.
Cutting tools: Cobalt alloys have excellent hardness and wear resistance, so they are widely used in the manufacture of cutting tools, such as drills, milling cutters, planer cutters, etc. Cobalt alloy cutting tools can provide longer service life and higher cutting efficiency.
Chemical catalysts: Cobalt catalysts are commonly used in chemical reactions such as hydrogenation, oxidation, and dehydrogenation. For example, cobalt catalysts can be used in reactions such as catalytic reforming, cracking, and hydrogenation in oil refining, as well as oxidation, carbonylation, and cyclization in synthetic chemistry.
Lithium cobalt oxide: Lithium cobalt oxide is an important cathode material that is widely used in lithium-ion batteries. Lithium cobalt oxide has high energy density, long life, and low self-discharge rate, making it suitable for applications such as power tools, electric vehicles, and energy storage systems.
Cobalt pigments: Cobalt salts can be prepared into pigments of various different colors, such as blue, green, and pink. These cobalt pigments are widely used in painting, ceramics, glass and plastics.
Cobalt is a transition metal element with a variety of characteristics and physical properties. The following is a detailed introduction to the physical properties of cobalt:
Density: Cobalt has a density of 886 grams cubic centimeters, slightly higher than most common metals. This gives cobalt a certain sense of weight and texture.
Melting and boiling point: Cobalt has a melting point of 1495 degrees Celsius and a boiling point of 2870 degrees Celsius. This means that cobalt has relatively high melting and boiling temperatures, making it stable in high-temperature environments.
Hardness: Cobalt is a harder metal, with a hardness of about 5 on the Mohs scale5。This makes cobalt resistant to abrasion and scratches and is suitable for the manufacture of wear-resistant materials and cutting tools.
Magnetism: Cobalt is a ferromagnetic material that is strongly magnetic. It is able to attract magnetic substances such as iron and can maintain its own magnetism. This makes cobalt very useful in electronic and magnetic applications such as magnets, magnetic recording**, etc.
Electrical conductivity: Cobalt is a good conductive material with high electrical conductivity. This makes cobalt widely used in electronic and electrical applications, such as batteries, circuit components, etc.
Thermal conductivity: Cobalt has a high thermal conductivity and is able to conduct heat energy quickly. This gives cobalt an advantage in high-temperature applications such as superalloys, rocket engines, etc.
Crystalline structure: The crystal structure of cobalt is the densest cubic structure that is tightly packed. This structure gives cobalt good strength and stability.
In addition to the above-mentioned physical properties, cobalt also has good corrosion resistance, plasticity, and weldability, making it widely used in many fields. However, it is important to note that cobalt is oxidized in the air to form a cobalt oxide film, so protective measures are required in some cases.
Cobalt is a fourth-period, group element with an atomic number of 27 and an element symbol of CO. It has an atomic weight of 589332。The chemical properties of the cobalt element are as follows:
Reactivity: Cobalt is a relatively stable metal that does not react with oxygen, water, and acids in the air under most common conditions. However, in acids at high temperatures and at higher concentrations (such as nitric acid, hydrochloric acid, and sulfuric acid), cobalt is dissolved and oxidized.
Oxidation states: Cobalt can form a variety of oxidation states, the most common being +2 and +3 valence. Among them, the compound of +2 valent cobalt is more common and stable. The oxidation state of cobalt affects its chemical properties and reactivity.
Reaction with oxygen: At high temperatures, cobalt reacts with oxygen to form cobalt oxides (COO, CO3O4).
Reaction with non-metals: Cobalt can form compounds with non-metals, such as sulfide (COS), cyanide (CO(CN)2), etc.
Reaction with acids: Cobalt is able to react with acids to produce the corresponding salts and water. For example, cobalt reacts with nitric acid to form cobalt(II) nitrates and nitrogen oxides.
Compounding ability: Cobalt is a good coordination agent, which can form stable coordination compounds with other substances. This makes cobalt widely used in coordination chemistry and catalysts.
Catalytic properties: Cobalt and its compounds have important applications in catalytic reactions, such as hydrogenation, oxidation and olefin polymerization.
It is important to note that due to the toxicity of cobalt to humans, especially organocobalat compounds, it is necessary to pay attention to safety measures when using and handling cobalt compounds.
The distribution of cobalt in nature is relatively sparse, with an average content of only 0001% (quality). In the earth's crust, cobalt is mainly associated with metallic elements such as iron, nickel, and copper, and there are basically no independent cobalt deposits. Common cobalt-bearing ores include cobalt pyroxene (Coass), rhocobalt ore (CoCO3) and arsenic cobalt ore (Coass). These ores are mostly found in serpentine, porphyry, and other rocks, and the cobalt content can range from trace to high.
The oceans are important reservoirs of cobalt, with a total of about 2.3 billion tonnes of cobalt in the world's oceans, mainly in surface and deep waters. In the ocean, cobalt mainly coexists with elements such as iron and manganese in the form of oxides, hydroxides, and carbonates.
The mining and smelting of cobalt mainly follow the following steps:
Ore exploration: Mineral resource exploration is first required to look for ore deposits containing cobalt. Common cobalt-containing ores are mainly zinc alum in zinc ores, as well as oxides, sulfides and carbonates in lead, copper and other ores.
Mining: Mining operations are carried out after the cobalt-containing deposits have been identified. Specific mining methods vary depending on the type of deposit and geological conditions, such as open-pit mining, underground mining or hydrological excavation.
Crushing and crushing: After mining, the ore is subjected to a preliminary crushing and crushing operation to reduce the size of the ore particles.
High-temperature smelting: The ore is heated to a high temperature so that the metal part of it melts. Through a metallurgical process, the metal in the ore is separated from other impurities. In the zinc ore smelting process, cobalt is often extracted together with zinc and separated by different separation and refining techniques.
Electrolysis: In some smelting processes, such as electrolysis, electrolytic cells are used to reduce metal ions to pure metals. In this step, an electric current and appropriate electrolyte treatment will be used to extract cobalt of higher purity.
Refining and purification: In order to obtain high-purity cobalt, further refining and purification steps may be required, such as vacuum distillation, gas chromatography, etc.
The common detection methods of cobalt mainly include atomic absorption spectrometry, atomic fluorescence spectrometry, atomic emission spectrometry, inductively coupled plasma mass spectrometry and X-ray fluorescence spectrometry. These methods are described in detail below:
Atomic Absorption Spectrometry (AAS): Atomic absorption spectroscopy is a commonly used method for measuring the amount of cobalt. It is measured using the principle that the cobalt atoms in the sample absorb light of a specific wavelength. The sample is first dissolved or melted, and then the cobalt in the sample is converted to an atomic state by means such as a flame, air-ethylene, or graphite furnace, and then measured using the absorption line of the cobalt. This method has the advantages of high sensitivity, good accuracy and simple operation.
Inductively Coupled Plasma Spectroscopy (ICP-OES): Inductively coupled plasma spectroscopy is a highly sensitive method for measuring cobalt content. It is measured using the cobalt atoms in a sample that emit a specific wavelength of light when excited by an inductively coupled plasma. This method has the advantages of high resolution, high accuracy, and a wide linear measurement range, and is suitable for measuring various types of samples.
Inductively Coupled Plasma Mass Spectrometry (ICP-MS): Inductively Coupled Plasma Mass Spectrometry is a highly sensitive and selective method for measuring cobalt content. It uses the cobalt atoms in the sample to be excited by an inductively coupled plasma and then analyzed and measured by a mass spectrometer to analyze and measure the resulting ions. This method is advantageous when measuring trace and ultra-trace amounts of cobalt and can determine multiple elements simultaneously.
X-ray fluorescence spectroscopy (XRF): the sample is irradiated with high-energy X-rays, and the cobalt atoms in the sample will emit a fluorescence signal of specific energy after being excited by X-rays, and the content of cobalt is determined by measuring the intensity of the fluorescence signal.
In addition to the above methods, molecular absorption spectrometry and other methods are used to measure cobalt. Accurate information on cobalt content can be obtained by selecting the appropriate method for measurement according to the need. These commonly used detection methods have the characteristics of high sensitivity, high accuracy and good selectivity, and are widely used in the detection of cobalt in environmental monitoring, food safety, biomedical and other fields. Different methods are suitable for different sample types and content ranges, and choosing the right detection method can improve the detection effect.
Choosing the right method for the detection of cobalt should be based on factors such as the specific sample type, the determination requirements, and the cobalt content range.
In elemental measurement, atomic absorption method has high accuracy and sensitivity, which provides an effective means to study the chemical properties, compound composition and content of elements.
Next, we use atomic absorption to measure the amount of cobalt. The specific steps are as follows:
Prepare the sample to be tested. The sample to be measured is prepared into a solution, which is generally digested with mixed acids to facilitate subsequent measurements.
Choose the right atomic absorption spectrometer. Depending on the nature of the sample to be measured and the range of cobalt content to be measured, the appropriate atomic absorption spectrometer is selected.
Adjust the parameters of the atomic absorption spectrometer. According to the element to be measured and the instrument model, adjust the parameters of the atomic absorption spectrometer, including the light source, atomizer, detector, etc.
Measure the absorbance of the element cobalt. The sample to be measured is placed in an atomizer and a specific wavelength of optical radiation is emitted through the light source, which is absorbed by the element cobalt to be measured, resulting in an energy level transition. The absorbance of the element cobalt is measured by a detector.
Calculate the amount of cobalt. Based on the absorbance and standard curves, the cobalt content is calculated.
The following are the specific parameters used by an instrument to measure cobalt.
In practice, it is necessary to select the appropriate measurement method according to the specific needs and conditions of the site. These methods are widely used in laboratory and industrial applications for the analysis and detection of elements.
Cobalt (CO) standard: cobalt powder or cobalt wire (99.)99％）。
Method: Weigh 1000 g of cobalt metal, dissolved in a small amount of (1 1) Hno3, determined to 1 L with a level, the CO concentration in this solution is 1000 g ml. Store in a polyethylene bottle protected from light.
Flame Type: Air acetylene, lean flame.
Analysis parameters: wavelength (nm) 2407
Spectral bandwidth (nm) 02
Filter factor 03
Recommended lamp current (mA) 4
Negative high pressure (V) 39800
Burner head height (mm) 5
Integration time(s) 3
Air pressure and flow rate (mpa, ml min) 020
Acetylene pressure and flow rate (mpa, ml min) 005，1300
Linear range (g ml) 002267～3
The linear correlation coefficient is 09998
Characteristic concentration (g ml) 0037
Limit of Detection (g ml) 0007
rsd(%)0.55
Calculation method: Continuous method.
Solution acidity 05％ hno3
Measurements**:
Calibration curves:
Interference: Silicon seriously interferes with the determination, and after treatment with perchloric acid or sulfuric acid (smoke), it does not interfere;Phosphoric acid has an effect on the assay;When the content of Ni exceeds 1500 g mL, the cobalt signal is severely inhibited, at which point the sample solution should be diluted or the laughing gas acetylene flame assay should be used.
For high sensitivity, 240 should be used7nm line, but if the cobalt content is high, it is better to use the more energetic 3527nm spectral line.
Cobalt-240The 7nm line should use a smaller spectral passband, otherwise Cobalt-241 cannot be separated1nm、240.4nm spectral line.
In practice, it is necessary to select the appropriate measurement method according to the specific needs of the site. These methods are widely used in laboratories and industry for the analysis and detection of cobalt.
Cobalt, this fascinating element, with its unique physical and chemical properties and wide range of applications, has brought great convenience and possibilities to mankind. Whether in batteries, aerospace, medical or other fields, cobalt plays an irreplaceable role. Although our understanding and application of cobalt is still in the process of deepening, the huge potential and value of cobalt are becoming increasingly apparent. With the continuous development of science and technology, we expect cobalt to play its unique advantages in more fields and bring more convenience and possibilities to our lives. Let's continue to explore this fascinating world of elements and reveal more hidden secrets and possibilities.