Formation of ferrocinel particles in the aquatic environment

Abstract

Simple chemical methods for producing ferrimagnetic particles include the co-deposition of metal salts in an alkaline medium, the transformation of inorganic precursor phases, and electrochemical and hydrothermal synthesis. Additional measures that contribute to improving the structure of particles (increasing their crystallinity) are heat treatment (calcination) of pre-dried powders in a furnace or ultrasonic treatment of dispersions during synthesis. Taking into account the high cost of many physical synthesis methods due to significant energy costs, today methods based on the formation of dispersed raw materials at low temperatures are considered economically interesting. The process of co-precipitation of metal salts in a weakly alkaline medium is one of the simplest and most effective classical chemical methods for the synthesis of dispersed iron oxide phases. One of the advantages of using the coprecipitation process for the synthesis of ferrimagnetic particles is the possibility of obtaining a significant amount of nanoscale material. At the same time, when using this method, it is expected to obtain polydisperse mixtures with a very large range of particle size distribution, which makes it impossible to use them in practice when creating a number of materials with complex or specific (biomedical) functional purposes. From the point of view of physical chemistry, the co-precipitation process consists of two stages: supersaturation of the solution with the formation and destruction (dissolution) of nuclei and secondary slow crystallization (redeposition) of particles with a perfect structure. Obviously, in order to obtain monodisperse iron oxide dispersions, these two stages must be spatially separated.