Zero-waste recycling method for textile dyeing sludge by magnetizing roasting–magnetic separation process and ceramic filter preparation

We developed an environmental recycling process for textile dyeing sludge that involved a magnetizing roasting–magnetic separation process followed by the preparation of a ceramic filter. The optimal parameters for the magnetizing roasting process included blending the textile dyeing sludge with 5.0% content of coal and roasting at 800 °C for 45 min. The main iron-bearing mineral (Fe 2 O 3 ) was converted to Fe 3 O 4 . The roasted ore was beneficiated by low-intensity magnetic separation (0.15 T strength of the magnetic field). A concentrate with 57.85% iron grade and 68.11% iron recovery was obtained. A ceramic filter material produced from the tailings of the magnetic separation process met the national standard requirements for water treatment applications. These results offered an effective approach to solve an environmental problem associated with textile dyeing sludge waste products.