The process of chemical reaction between acidic substances in automotive rust removers and rust is mainly the reaction between acid and iron oxide (the main component of rust). This reaction is a typical acid-base neutralization reaction.
The main component of rust is iron oxides, such as ferric oxide (Fe2O3) or ferric oxide (Fe3O4). When acidic substances in rust removers (such as hydrochloric acid HCl, sulfuric acid H2SO4, etc.) come into contact with rust, hydrogen ions (H+) will combine with oxygen ions (O2-) in rust to form water molecules (H2O). Meanwhile, iron ions (Fe3+or Fe2+) are released from rust and combine with acid ions (such as Cl -, SO42-, etc.) to form soluble iron salts.
For example, when hydrochloric acid reacts with ferric oxide, the reaction equation is as follows:
6HCl+Fe2O3 → 2FeCl3+3H2O
In this reaction, hydrogen ions combine with oxygen ions in iron oxide to form water, while iron ions combine with chloride ions to form soluble ferric chloride.
Similarly, when sulfuric acid reacts with rust, soluble iron sulfate and water are generated.
These soluble iron salts can be rinsed off during the cleaning process to remove rust. It should be noted that this reaction process may release heat, so safety regulations should be followed during operation to avoid burns or other unexpected situations.
In addition, as the acidic substances in the rust remover may cause corrosion to the metal substrate, the reaction time and concentration should be controlled during use to avoid excessive damage to the metal surface. After rust removal is completed, subsequent treatments such as painting or rust prevention should be carried out in a timely manner to protect the metal surface from further corrosion.
