Evapo-Rust™ is a world leading chemistry employing selective chelation for rust removal. Evapo-Rust™ is sewerable in neat form and works at a pH ranging from 6 delivered to 7 as a spent solution. Evapo-Rust™ is a full replacement for acid and caustic rust removal applications, yet is non-hazardous, non-corrosive, non-flammable, and poses no environmental or health hazards. Evapo-Rust™ is a clear to yellow liquid best suited for dip tank applications, but in no way limited to this technique. In its simplest application, a plastic pail will suffice as an impromptu dip tank application. Rust removal is accomplished with no operator input once the piece is fully immersed. Most pieces/parts do not even need dismantling before soaking. Evapo-Rust™ does not harm Aluminium, Brass, Copper, Vinyl, Plastic, Wiring, Rubber, Chrome, or Non-oxide paint. Light rust is removed in as little as 5 to 30 minutes. Medium rust up to 6 hours, and heavy rust takes up to 24 hours. The chemistry is corrosion inhibiting for up to 2 weeks or it can be rinsed off for immediate painting.
Evapo-Rust™ has no transportation restrictions.
U.S. economic loss to corrosion costs $276 billion dollars annually, $20 billion in the Department of Defense alone. Figure 1 (right) shows the actual cost of corrosion broken down by industry. Current methods of corrosion or rust-removal include Acids, Caustics, Converters, Electrolysis, and Mechanical. These methods subject Personnel, Equipment, and the Environment to toxic and hazardous materials, emissions, conditions, and waste. How big is the scope? As an example, the steel pickling industry utilized an estimated 245 Million gallons of Hydrochloric Acid alone in 1991 and emits approximately 920 Mg/Year of HCI.
The solution works by removing Iron (Fe II) from Iron Oxide and binding it in a ligand complex. (See illustration below). The Selective-Chelator is not strong enough to remove Iron-to-Iron bonds from un-corroded steel and does not harm the underlying metal. The Chelator is too expensive to use large quantities in the finished product. An organic chemical that easily loses sulfur to form ferric sulfate was added to remove iron from the Iron-Chelator complex. This allows the Chelator to remove more Iron from Iron Oxide. The sulfur-bearing compound is much less expensive than the Chelator and makes Evapo-Rust™ economical to use. Evapo-Rust™ has a chemical carrying capacity of 300grams of pure, dry rust per 5 litres.
The chemistry is endothermic so it requires some ambient heat to work. In temperatures below 5°C, the reaction is severely retarded. At 15-20°C it is pleasantly quick, and at 35-50° it is very active. Higher temperatures do not harm the liquid, but for worker safety they are not necessary. Only water evaporates from the fluid, and can be replaced without loss of performance. It is recommended to use Evapo-Rust™ as a free liquid in a dip-tank application. After treatment, the part can be water rinsed for painting, plating, or any other type of corrosion protective coating. If left un-rinsed, the fluid will dry on the treated surface to a hard, short-term corrosion resistant coating with no corrosion removal properties. As a dry film, it inhibits oxidation indoors for 10 to 14 days, depending on the humidity.
Observations show the ability of this chemistry to remove Iron Oxide without having any effect on Plastic, Acrylic and Poly Paint, Rubber, Butyl, Tin, Aluminium, Copper, Brass, and a host of other tested materials. The precise types of Iron Oxide and coatings affected are: Maghemite - γ Fe2O3, Magnetite - Fe3O4 , Wustite – FeO, Iron hydroxide - Fe(OH)2 , Iron Trihydroxide (Bernalite) – Fe(OH)3, Akageneite - β FeOOH, Feroxyhite - δ FeOOH, Lepidocrocite - γ FeOOH 11 and Parkerizing (Both types: Manganese & Zinc). Hematite - α Fe2O3 and Goethite - α FeOOH are not affected by Evapo-Rust.