Chemical thermodynamics of fluoride-ammonium processing of ash and slag technogenic waste

Relevance. The need to replace the import of alumina in the aluminum industry with its production from domestic raw materials for solving the problem of raw material safety, and accumulation of a large amount of ash and slag technogenic waste of thermal power plants. On the one hand, they violate the environmental situation, and, on the other hand, are a kind of minerals located on the surface of the Earth and, therefore, are not required the cost of their extraction from the bowels of the earth. Aim. To study chemical thermodynamics of reactions of ammonium fluoride processing of technogenic ash and slag raw materials in order to optimize the technological process using a program for preliminary calculations of thermodynamics of chemical reactions. Methods. Theoretical analysis, computer calculation, experimental research using chemical, X-ray phase, emission and absorption spectral and of other types of analysis. Results and conclusions. The authors have studied chemical thermodynamics of ammonium fluoride technology for processing ash and slag man-made waste from thermal power plants of the Amur region. They obtained various useful products: nanoscale amorphous silica, alumina grades G0 and G1, red iron oxide pigment Fe2O3, concentrate (Ca, Y)F2 enriched with rare earth and refractory elements, noble metals and other useful components. For preliminary calculations of thermodynamics of chemical reactions, the authors applied a vb program with thermodynamic potentials and their derivatives of more than 300 chemicals database, which they created on the basis of a text file. The program allowed calculating the changes of enthalpy, Gibbs potential, equilibrium constants, as well as errors of calculations of Gibbs potential and enthalpy changes.