Hydrofluoric acid

Hydrofluoric acid (CAS 7664-39-3), also known as anhydrous hydrogen fluoride (HF), is an inorganic acid with exceptional ability to dissolve silica, oxides, and mineral scales that resist other acids.

Where is Hydrofluoric acid used?

• Electronics: etches silicon dioxide layers in semiconductor and flat-panel display manufacturing
• Electronics: cleans wafer surfaces with precision tolerances other acids cannot achieve
• Metal processing: pickles stainless steel and titanium, removing oxide scale and activating surfaces ahead of finishing
• Fluorochemical synthesis: primary fluorinating agent in production of refrigerants, fluoropolymers, and pharmaceutical intermediates
• Mining and hydrometallurgy: dissolves silicate gangue minerals
• It assists in uranium conversion processes during ore processing.
• Used in the extraction of rare metals such as niobium or tantalum.
• Used for etching glass and enamel.
• Used as a cracking catalyst in oil refineries.

Formulation notes

• Attacks glass and other silica-containing materials.
• Silica products such as floor absorbent, cat litter, or sand can produce toxic silicon tetrafluoride gas when used on spills.

Typical specification

• Aqueous solution containing 50% w/w hydrogen fluoride and 50% w/w water.
• Covered as a 70% aqueous solution.

Regulatory status

• Classified as fatal if inhaled under CLP hazard statement H330.
• EU occupational exposure limit is 1.5 mg/m³ as TWA and 2.5 mg/m³ as STEL.
• Under the EU CLP Regulation, has index number 009-003-00-1.

Storage, packaging and handling

• Reacts violently with bases and is corrosive to common metals, forming flammable or explosive hydrogen gas.
• Should be stored only in its original container, separated from food, feed and incompatible materials, in a cool place with floor-level ventilation and no access to drains or sewers.
• Containers must be tightly closed again immediately after use.
• Proper hazardous substance storage must follow TRGS 510 and disposal must follow waste code AVV 060103.

Technical content is compiled and updated by the SoleChem product team from public technical sources; the certificate of analysis (COA) governs product-specific specifications.