Helium (He) is a colorless, odorless, non-toxic noble gas and the second-lightest element. It is chemically inert and boasts the lowest boiling point of any element, approximately -269 degrees Celsius. These properties make it highly sought after for uses ranging from inflating balloons to cooling superconducting magnets in Magnetic Resonance Imaging (MRI) machines. Obtaining helium involves methods from simple consumer purchases to complex industrial separation processes.
Obtaining Helium for Immediate Consumer Needs
The most common way for the general public to acquire small amounts of helium is through retail channels like party supply stores or online vendors. These consumer-grade products are typically sold as small, disposable tanks intended for filling a limited number of balloons. This “balloon-grade” helium is often less pure than specialized applications require, sometimes containing 80% to 99.99% helium, with the remainder being air or nitrogen. Acquiring larger, higher-purity cylinders, such as those needed for welding or cryogenics, requires engaging with specialized industrial gas suppliers. These suppliers offer grades like Grade 5.0 (99.999% pure) and often require commercial accounts or specific safety training for handling and rental.
The Primary Industrial Process: Extraction from Natural Gas
On a commercial scale, virtually all usable helium is obtained as a byproduct during the processing of natural gas. Helium accumulates in underground reservoirs, requiring concentrations generally exceeding 0.3% by volume to be economically viable for extraction. This extraction leverages the element’s low boiling point through cryogenic distillation. The natural gas stream, primarily methane, is cooled to increasingly lower temperatures. As the temperature drops, components like water, carbon dioxide, and hydrocarbons liquefy and separate out, while helium remains gaseous.
Purification
The initial separation yields a crude helium mixture, often containing 50% to 75% helium along with nitrogen. This crude gas is further purified by passing it through additional cooling and separation stages, often integrated with a nitrogen rejection unit. This achieves the high purities required for industrial and scientific applications. This complex, energy-intensive cryogenic process is the only commercially scalable method to secure large volumes of terrestrial helium.
Why Helium is Scarce: Natural Formation and Atmospheric Loss
Helium’s scarcity and high value stem from its slow natural formation and its inability to be retained by Earth’s gravity. All terrestrial helium is radiogenic, originating from the radioactive decay of heavy elements like uranium and thorium deep within the Earth’s crust. This decay releases alpha particles, which capture electrons to become stable helium atoms. This generation process is constant but extremely slow, contrasting sharply with industrial consumption. Once this light, inert gas is extracted and released, it functions as a non-renewable resource. Because of its low atomic mass, helium atoms move fast enough to reach escape velocity, escaping Earth’s gravitational pull into space. This constant atmospheric loss means helium is permanently lost once utilized, unlike other gases that can be recycled.
Safe Handling and Storage of Pressurized Helium
Helium is stored under high pressure, necessitating strict safety protocols for handling and storage. Pressurized cylinders must be secured upright, typically by chaining them to a wall or dedicated stand, to prevent falls and damage to the valve or regulator. Since helium is inert and not flammable, its primary risk is simple asphyxiation by displacing breathable oxygen in confined spaces. Therefore, all use and storage areas must be well-ventilated to prevent gas accumulation in the event of a leak. Cylinders should be kept away from excessive heat, as increased temperature raises internal pressure and can lead to rupture. Always use a properly rated pressure regulator designed for the specific cylinder to control the gas flow safely.