Cuprous oxide is an important inorganic chemical raw material and has a wide range of applications in coatings, glass, ceramics, plastics, agriculture and industrial catalysis. In China, the amount of cuprous oxide has increased year by year, and research on cuprous oxide has been active in recent years. At present, although there are many methods for preparing cuprous oxide, cuprous oxide having uniform particle size and stable performance is rarely obtained, and many preparation methods are complicated and complicated. The use of sodium sulfite to reduce copper sulfate raw materials is easy to obtain, has low requirements on equipment, convenient operation and pure product. However, the SO 2 produced during the reaction is dissolved in the reaction solution to increase the acidity of the solution, so that the yield and content of cuprous oxide are greatly reduced.
At present, the method generally uses NaOH or Na_2CO_3 to adjust the pH value of the reaction solution, but the addition of the alkali solution causes the local solution to chemically react to form Cu(OH)_2, and the CuO is heated to make the obtained product impure. A buffer solution is added to the solution to adjust the pH of the solution. Through a number of tests, it was found that the suitable pH value of the solution was about 5.0, so the HAc-NaAc buffer system was selected. Pure cuprous oxide was prepared by reducing the copper sulfate with sodium sulfite under normal pressure and hydrothermal conditions with HAc-NaAc solution as buffer system. The samples were characterized by chemical analysis, scanning electron microscopy, X-ray diffraction, differential thermal-thermogravimetry, etc. The optimum reaction conditions for the preparation of cuprous oxide under normal pressure and hydrothermal conditions were determined and oxidized. Cuprous copper was studied for oxidation kinetics.
Through the single factor experiment and orthogonal experiment under normal pressure, the main factors affecting the preparation of cuprous oxide under normal pressure were reaction time, reaction temperature, amount of buffer and ratio of reactants. The optimum experimental conditions for cuprous copper are: reaction temperature 368 K, reaction time 90 min, buffer solution used twice as much as the reaction solution, and reactant ratio of 1.2. The color of the obtained product is purple-red, the product is relatively pure, and the particles are about 1 μm, which is approximately spherical. The yield of cuprous oxide was 86%, and the content of cuprous oxide was determined by redox method to be 98.47%, and the bulk density of the product was 0.6548 g/cm~3. The single factor experiment and orthogonal experiment of preparation of cuprous oxide by hydrothermal method showed that the main factors affecting the preparation of cuprous oxide by hydrothermal method were reaction time, reaction temperature, buffer dosage and filling degree. The optimum experimental conditions for preparing cuprous oxide are reaction temperature 353K, reaction time 12h, buffer amount 4 times of the reaction solution, and filling degree 0.80. The yield of cuprous oxide obtained was 88%.