As is well known, the harm of heavy metal ions to the environment is terrifying, and heavy metals are indispensable raw materials in industry. To separate heavy metals from the process, it is necessary to develop green and environmentally friendly aluminum oxidation technology through research. Our company mainly uses magnesium salts, surfactants (wetting agents), and ash suppressants (without phosphate) as the main ingredients. Therefore, the medium temperature sealing of pores without heavy metals in aluminum oxidation technology has attracted widespread attention. Through aluminum oxidation experiments, the results show that the sealing quality is good, the service life of the tank solution is long, the energy-saving effect is significant, and the environmental effect is excellent. Nickel free medium temperature sealing is achieved by using acetate salts of alkaline earth metals, alkali metals, or other divalent or trivalent metals, where the metal ions can be lithium, magnesium, potassium, etc., instead of using nickel salts as the main component of the sealing technology. Then, sulfonated surfactants and ash suppressants are used to form a nickel free system. The sealing process can be divided into two steps: first, immerse the oxidized aluminum in a lithium salt solution at room temperature, and then seal the hole in hot water containing a dust suppressant. The sealing process based on light metal salts is suitable for sealing holes in transparent hard oxide films, but not suitable for dyeing aluminum oxide films, because light metal ions cannot prevent adsorbed organic dyes from leaching out during sealing. It is said that Europe has already introduced formulas based on lithium and magnesium salts to the market, which can achieve pore sealing The specific details of the sealing process and performance are currently unclear. The pore sealing of alkaline earth metal salts Ba2+, Sr2+, and Ca2+, It can improve the pitting corrosion resistance of aluminum aluminum oxide film, with Ca2+having the best effect, followed by Sr2+.
