Marine mineral tailings use in anticorrosive coatings

A new type of water-dispersive anticorrosive paint was prepared by using marine cobalt-rich crusts tailings which are the residue of cobalt-rich manganese crusts after the extraction of Co, Ni, Cu, Zn, Mn by acid leach. The first step making the paint is preparing the colored slurry by mixing the tailings (54.65%, mass) with water (40.78%) and some auxiliary materials (4.57%). The second step is mixing the colored slurry (40%) with a styrene-acrylate copolymer (40%), water (11.9%) and some auxiliary materials (8.1%). Test results indicate that the resistance to impact of the coating film is equal to or more than 490 Nmiddotcm, the resistance to saline water is more than 24 days. The tailings can provide both physical and chemical corrosion protection. With their fine particle size the tailings can be dispersed into the styrene-acrylate copolymer to form a uniform coating film with relatively high bonding strength on surfaces to be protected. With a high Fe₂O₃ content the tailings provide physical cladding. With a high content of Sr and other trace elements the tailings can react with corroded ferrite or with other corrosive materials, such as S0₄ ^2-, to form unreactive oxides or inert compounds. In this way, the tailings serve as chemical preservation agents. P₂O₅ contained within the tailings may combine with metallic elements or may react with polar groups in the styrene-acrylate copolymer to form stable complex compounds to keep corrosion from developing. Oxidizing and reducing properties of rare earth elements may accelerate the formation of a polymer network of coating molecules and shorten both the solidifying and film-forming times for the coating. The tailings also likely enhance the strength and water resistance of the resultant coatings.