Effects of Metal Oxides on Carbonation and Coking of High-Salinity Organic Wastewater

Slag is difficult to treat quantitatively due to the formation of a molten mixture in the carbonization process of high-salinity organic wastewater. Thus, aiming at solving this difficulty, the effects of metal oxide additives, additive ratio, furnace burden ratio, and carbonization temperature on the carbonization and coking of high-salinity organic wastewater are systematically analyzed. The analysis is performed using scanning electron microscopy, X-ray diffraction, and Vickers hardness tests. The results show that all five metal oxide additives can reduce the hardness of carbonized products. The relative effect of reducing the coked hardness is as follows: MgO>CaO>kaolin>Fe2O3>Al2O3. Thus, the effect of MgO on reducing the coking hardness is stronger than that of the other four metal oxides, reducing the hardness of carbonized products by approximately 81%. Furthermore, the adding charge can reduce the hardness index by at least 60%. When the carbonization temperature is higher than 800°C, the hardness index of the carbonized product decreases by approximately 5% each 50°C of increase in temperature. This study shows that the addition of metal oxides can effectively reduce the hardness of coking during the treatment of high-salt organic wastewater by carbonization and oxidation and provide theoretical support for the subsequent treatment of high-salt organic wastewater by carbonization and oxidation.