Sintering process of Fenton sludge-derived water treatment filler

Fenton sludge containing (20–40% iron content) is produced by Fenton oxidation technology during the treatment of refractory organic pollutants, which is a hazardous industrial waste. Moreover, the landfill and incineration of Fenton sludge result in the waste of iron resources. In this context, Fenton sludge obtained from the advanced treatment of papermaking wastewater was mixed with coal slime and coal fly ash to prepare water treatment fillers via a high-temperature sintering. Specifically, the effects of raw material ratio, sintering temperature and sintering time on the filler properties were analyzed, including compressive strength, bulk density and water absorption of capacity, and the optimum process conditions were determined. It was confirmed that under the optimal process conditions of Fenton sludge: coal fly ash: coal slime = 5:3:2, sintering temperature 950 ℃, sintering time 40 min, preheating temperature 400 ℃ and preheating time 30 min. The analysis was carried out on the physical properties, the leaching concentration of heavy metals, micromorphology, phase composition and element content of the fillers. Under the conditions of pH 3, m(COD_Cr):m(H₂O₂) 1:1.5, catalyst dosage 15 g L⁻¹, reaction time 100 min, COD_Cr reduced to 48.65 mg L⁻¹.