Influence of gas environment on the composition and properties of heat treatment products of galvanic slimes

Abstract

The process and composition of heat treatment of products of galvanic slimes which have different qualitative and quantitative composition of chromophore determining components are studied depending on the heat treatment conditions. It is established that the heat treatment of the galvanic slimes under different oxygen concentrations in the gas phase and chromophore determining compounds leads to the formation of a number of phases of variable composition in the form of oxygen solid solution in different modifications of iron oxide ?magnetite Fe3O4, maghemite ?-Fe2O3and hematite ?-Fe2O3. It is shown that crystal structures of solids with well-defined arrangement of atoms retain stoichiometry only at a certain partial pressure of oxygen on the step of slime heat treatment. This pressure is a function of temperature. The formation of ferrite products determines the color of pigment-filler and content of water-soluble substances.