Physicochemical Model of the Formation of Allocate Gold

Abstract

This work is devoted to the kinetic analysis and modeling of patterns of the formation of nanoforms of metallic gold and mechanisms of the formation of metal macroparticles. The kinetics of the process in a steady state in solution and in a flow simulating the processes of deposit formation is considered. The autocatalytic nature of the synthesis of gold nanoparticles is shown, where the reverse oxidation of Au⁰ by strong oxidizer Au³⁺ is of fundamental importance. The kinetic behavior of the system is modeled, depending on the initial concentration of the reagent (Au³⁺), concentrations of autocatalytic seeds (Au¹⁺, Au⁰), and the concentration of the reducing agent. The dependence of the multi-stage process on temperature is analyzed. The formation of a gold placer in a flow is modeled mathematically, based on the theory of ideal displacement reactors. The model includes a zone of dispersed mineral gold (or nanodistributed gold), a zone of the hydroflow, and a zone of coagulation in the formation of macroparticles on a metal nucleus (a zone of precipitation). Calculations are made of the dependence of reagent distribution on the concentration of the reducing component, the rate of hydraulic flow, the concentration of coagulants, and the precipitation of seeds.