Low-cost V−W−Ti SCR catalyst from titanium-bearing blast furnace slag

• Waste titanium-bearing furnace slag was converted into high-value SCR catalyst.
• A low-cost method was proposed to produce the V−W−Ti SCR catalyst.
• Silica and iron impurities were found to be the promoter for SCR of NOx.
• Slag-based SCR catalyst exhibited good deNOx activity and stability.

Preparing SCR (selective catalytic reduction) catalyst from the titanium-bearing blast furnace slag not only realized the high-value utilization of the slag but also provided a low-cost method for V−W−Ti catalyst production. Titanium dioxide was extracted from titanium-bearing blast furnace slag and used as the carrier of V−W−Ti SCR catalyst. Although with 21% SiO2 and a little Al and Fe impurities, the slag-based SCR catalyst exhibited higher deNOx activity and wider active temperature range than commercial TiO2-based catalysts. Under the conditions of NO = 600 ppm, GHSV (gas hourly space velocity) = 24,000 h−1, NH3/NO = 0.8 and O2 = 3%, the slag-based SCR catalyst exhibited NO conversion of higher than 77% in the temperature range of 250–450 °C. For a test at 300 °C, the slag-based catalyst also showed outstanding catalytic stability in the flue gas containing 2000 ppm SO2 and 10% H2O.

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