Determination of optimal parameters for the production of copper-containing particles during plasma-chemical treatment of aqueous solutions
The process of obtaining copper-containing particles from aqueous solutions is considered when using contact non-equilibrium plasma of reduced pressure. One of the most problematic areas of this technology is the need for the difficulty in choosing the parameters of the plasmachemical treatment of the solution leading to the production of the desired quality. This is due to the fact that the physical and chemical mechanisms of the reactions are rather complex and when they occur, synergistic effects are observed, the dependencies of which are not entirely clear. In the course of the analysis, the possibilities of improving the technological scheme are revealed through: 1) control of the inlet pH of the solution, ensuring the optimal yield of copper compounds; 2) use of the spent solution in the tank with the initial solution for its acidification; 3) refinement of the reactor block for the purpose of processing the solution in film or close to it, which should lead to an increase in the yield of copper oxides and a decrease in the particle size. The characteristics of the process of obtaining sediments are studied. At a concentration of C(Cu) = 10<sup>-1</sup>-10<sup>-2</sup> mol/l, the optimum pH range lies in the range 3.5-4.5. Let’s note that an increase in the current intensity of the process is accompanied by an increase in both the yield of the sediment and its density. Reducing the Cu concentration at the same current parameters gives more loose sediments. At the same time, a decrease in the liquid layer promotes an increase in the yield of oxide compounds. Also, when the thickness of the processed liquid layer is reduced, the particle size of the sediment decreases. The composition and sizes of the obtained particles are determined. With a thickness of the treated solution layer of 0.25 m, the oxide part is 50 % and 49 % at 0.1 and 0.2 bar, respectively, and at 0.01 m - 86 %, and 87 %. The dimensional characteristics of the particles are in the range 10-100 nm.