What is ferrovanadium used for?

Ferrovanadium (FeV) is a key alloy in modern metallurgy, consisting of iron and vanadium, with the vanadium content ranging from 35% to 85%. This grey-silver crystalline solid is usually processed into a fine powder, called "ferrovanadium powder", and is mainly used as an additive to enhance the properties of steel and other ferroalloys. Its ability to increase strength, hardness and corrosion resistance makes it an indispensable material in industries ranging from construction to chemical processing. This article explores the production, applications and economic significance of ferrovanadium, and provides a comprehensive overview of its role in industrial applications.

Ferrovanadium Composition and production

Ferrovanadium is an alloy composed of iron and vanadium, usually derived from vanadium pentoxide extracted from titaniferous magnetite or vanadium slag. The vanadium content depends on the intended use, with common grades containing 40% to 80% vanadium. The production process involves a variety of reduction methods, such as:

Aluminothermic reduction: A highly exothermic process that uses vanadium pentoxide, aluminum powder, steel scrap and lime to produce ferrovanadium with a low carbon content (0.02% to 0.06%C). This method is suitable for the production of high-quality alloys.

Silicon reduction method: produces medium-grade ferrovanadium or ferrosilicon vanadium alloys suitable for less demanding applications.

Direct alloying of vanadium slag: a cost-effective method that does not require vanadium extraction, but produces low-quality alloys containing impurities such as carbon, silicon, sulfur, phosphorus and chromium.

The resulting alloy has a melting point of about 1480°C, a solid density of 7.0 tons/m3 and a bulk density of 3.3-3.9 tons/m3. It is usually processed into blocks less than 200 mm for industrial use.
 

Applications of ferrovanadium

The versatility of ferrovanadium stems from its ability to enhance the mechanical and chemical properties of ferroalloys. The following are its main applications, categorized by industry and function.

1. Steel production

The steel industry is the largest consumer of ferrovanadium, accounting for a large portion of global vanadium consumption (e.g., 94% in the United States in 2017). Ferrovanadium is used as a general-purpose hardener, strengthener, and corrosion protection additive for a variety of steels, including:

High Strength Low Alloy Steel (HSLA): Ferrovanadium improves the tensile strength-to-weight ratio, making HSLA steels ideal for construction (e.g., bridges, buildings), automotive components (e.g., chassis, axles), and pipes. Its fine grain structure, created by the formation of vanadium carbides (V4C3), improves toughness and resistance to torsion.

Tool Steel: Used to make cutting tools, dies, and other high-wear parts due to its ability to increase hardness and wear resistance. For example, ferrovanadium is essential for producing durable hand tools such as wrenches, screwdrivers, and ratchets.

Carbon and Alloy Steel: Improves overall quality for structural and mechanical applications such as gear components and crankshafts.

Rail and Die Steel: Ferrovanadium is used to make specialized steels for railroad tracks and die-casting dies, where durability and high-temperature resistance are critical.

When coated with ferrovanadium nitride, the wear resistance of steel can be increased by 30-50%, making it suitable for high-performance applications such as springs and high-speed tools.

 

 

2. Chemical Processing Industry

The corrosion resistance of ferrovanadium makes it valuable in the chemical processing industry, especially in high-pressure, high-throughput fluid handling systems. It is used in equipment that handles corrosive substances, such as:

Sulfuric acid production: Ferrovanadium treated steel resists sulfuric acid corrosion, ensuring long life for industrial-scale systems.

Hydrochloric acid and alkaline reagents: The alloy's tolerance to these chemicals makes it suitable for pipes and tanks in chemical plants.

This application is critical to maintaining the integrity of the system under harsh chemical conditions.

3. Special metallurgical applications

Ferrovanadium is used in specific metallurgical processes, including:

High-temperature tempering of hardened steel: Ferrovanadium powder, commonly known as NFE reagent, is used in chloride salt baths during heat treatment. It increases the viscosity of the bath, ensures stable formation of coatings, and improves the surface properties of the steel.

Production of vanadium master alloys: Ferrovanadium is produced by thermite reaction to form master alloys, which are then used in alloying processes for special applications.

Ferrovanadium is typically processed through a cost-effective thermomechanical process to produce stronger, tougher, more durable and more wear-resistant steel, which is the basis for critical infrastructure, transportation, energy production and heavy machinery.