Flue-gas desulfurization is the main method of coal desulfurization. Potassium humate (KHA) solution was used to remove SO₂ from flue gas, and the effects of the potassium humate concentration, solution temperature, SO₂ concentration and oxygen content on SO₂ absorption efficiency were explored.

The results showed that the desulfurization performance of potassium humate absorbent is much better than that of an equal volume of water or potassium hydroxide solution with the same initial pH. The SO₂ concentration, reaction temperature and oxygen content greatly influence HEDT (high-efficiency desulfurization time).

When the concentration of KHA is between 0.024–0.120 g/L, HEDT increases as the potassium humate concentration increases; after desulfurization, the potassium humate product is poorly soluble in water and is easy to separate. Implementation of the desulfurization process by potassium humate mainly involves providing alkalinity and pH buffering agents in the desulfurization process.