The sulfur dioxide gas mixture was bubbled and removed through the water solution which contain suspended melamine particles using a multi-stage agitated reactor to increase gas-liquid interfacial area and the dissolution rate of melamine particles.
In gas-liquid-melamine fine particle system, it was found that the melamine fine particles was continuously dissolved and was used in SO₂ absorption. Therefore SO₂ absorption reaction was continued until the free melamine particles was completely consumed. The experiment also showed that the melamine sulfate produced from the reaction was easily regenerated by the thermal decomposition. And the SO₂ absorption capacities of the melamine regenerated by the thermal decomposition was similar to those of fresh melamine.
The amount of SO₂ removed per one mole of melamine decreased as the temperature of solution raised and the slurry concentration of solution increased. The SO₂ removal efficiency increased with agitation speed, pH of solution, slurry concentration of solution and liquid-gas flow ratio, however, decreased with the temperature of solution.