Tungsten oxide is considered one of the most refractory in this class of inorganic substances. In order to give the metal a characteristic, we analyze the qualities of the metal itself.
Tungsten Features
To understand the practical importance of tungsten oxide, we note that the metal itself has electrical resistance, linear expansion coefficient, and high melting point.
Pure tungsten has high ductility. The metal will dissolve in acid only when heated to a temperature of 5000 ° C. It interacts with carbon, forming tungsten carbide as a reaction product. The resulting compound is characterized by increased strength.
The most common tungsten oxide is tungsten anhydride. The main advantage of the chemical compound is its ability to reduce the powder to metal, forming lower oxides as by-products.
The metal is characterized by high density, brittleness and the ability to form tungsten oxide at low temperatures.
Tungsten Alloys
Scientists distinguish single-phase types of alloys, which contain one or more elements. The most known compound of tungsten with molybdenum. Alloying an alloy with a molybdenum element increases the tensile strength of tungsten.
Compounds are considered as single-phase alloys: tungsten - zirconium, tungsten - hafnium, tungsten - niobium. Rhenium gives maximum ductility to tungsten. Its addition does not affect the performance of refractory metal.
Metal production
In the traditional way, it is impossible to obtain alloys of refractory tungsten: reaching the melting point, the metal instantly passes into a gaseous form. The main option for obtaining pure metal is electrolysis. In industrial volumes, powder metallurgy is used to obtain tungsten alloys. For this, special technological conditions are created using vacuum.
Being in nature
Tungsten oxide, the formula of which is WO 3 , is called the highest compound. It is not found in nature in its pure form, but is part of tungsten ores. The process of extraction and processing of refractory metal involves several stages.
Higher tungsten oxide is isolated from the ore mass. Next, the compound is enriched, and after processing, pure metal is isolated.
In the process of manufacturing a thin tungsten wire, care is taken to completely remove impurities. Otherwise, the technical characteristics of the finished product will be significantly reduced.
Tungsten Applications
How to recover tungsten oxide? Hydrogen interacting with this compound helps to obtain pure metal. It is necessary in the manufacture of filaments, the creation of x-ray tubes, heaters and screens of vacuum furnaces, which are designed for use at high temperatures.
Steel, the alloying element of which is tungsten, is characterized by high strength properties. Products made from such an alloy are used in the manufacture of medical instruments, cutting inserts for drilling wells. The main advantage of the connection is the resistance to mechanical deformation.
The probability of occurrence during operation of finished products cracks and chips is rather low. The most popular steel grade, which includes tungsten, is considered to win.
High-quality catalysts, various paints, special pigments, etc. are made from the scrap of this rare metal. Tungsten crucibles and containers for radioactive waste are widely used in the modern nuclear industry.
The refractoriness of the metal plays a special role in arc welding. Since tungsten in its pure form is considered to be a rather rare metal, the tungsten ore beneficiation and processing procedure is carried out to obtain it. In its pure form, it has a light gray color with a characteristic metallic luster. Standard tungsten alloys, referred to as stellites, also include cobalt and chromium. The main component in such compounds is cobalt. Alloys are in demand in mechanical engineering.
Tungsten oxides
What features does tungsten oxide have (6), the formula of which is of the form WO 3 ? The metal is able to exhibit different degrees of oxidation: the variants with metal valency (4) and (6) have maximum stability. The first compound of the form WO 2 refers to acid oxides and has the following characteristics: high melting point and special density. This chemical compound is almost insoluble in water, but in case of heating it can dissolve in acids and alkalis. In the chemical industry, it is used as a catalyst in some reactions. For example, the WO 2 compound is used in the manufacture of ceramic products.
Tungsten oxide having a valency (6) also exhibits characteristic acidic properties. This compound interacts with alkalis, but is not able to dissolve in water. Given that the compound has a high melting point, it is used only as an accelerator of chemical processes.
Conclusion
In the course of inorganic chemistry, special attention is paid to the study of oxides, the analysis of their properties and the features of industrial applications. For example, at the final exam, ninth-graders are offered the following task: “Compose the formulas of the oxides of copper, iron, tungsten, and also determine their basic chemical properties.”
In order to successfully cope with the task, it is necessary to have an idea of the features of oxides. These are binary compounds in which oxygen is the second element. All oxides are usually classified into three groups: basic, acidic, amphoteric.
Iron and copper are elements of a subgroup, therefore, are capable of exhibiting valence variables. For copper, only two variants of oxides exhibiting the basic properties can be written — Cu 2 O and CuO.
Iron is not located in the main subgroup of chemical elements; therefore, oxidation states of +2 and +3 take place. In these cases, oxides of the following species are formed — FeO and Fe 2 O 3 .
Tungsten in binary compounds with oxygen most often exhibits valencies (4) and (6). Both oxides of this metal exhibit acidic properties; therefore, they are used in industry as accelerators of chemical processes.
The main purpose of all tungsten oxides is the separation of pure metal from them, which is in demand in the chemical and metallurgical industries.