Effect of V₂O₅ Addition on Oxidation Induration and Swelling Behavior of Chromium-Bearing Vanadium Titanomagnetite Pellets with Simulated Coke Oven Gas Injection into Blast Furnace

抄録

The study discusses the oxidation induration and swelling behavior of chromium-bearing vanadium titanomagnetite pellets (CVTP) with V₂O₅ additions, and the reduction swelling index (RSI) and compressive strength (CS) of reduced CVTP were investigated with simulated coke oven gas (COG) injection into the blast furnace (BF). The results show that the CS of CVTP decreases and the porosity of CVTP increases with increasing V₂O₅ additions. The proportion of microsize pore size distribution of CVTP between 0 to 5 µm decreases notably while the pore size distribution between 5 to 30 µm increases with increasing V₂O₅ additions. The V₂O₅ mainly exists in the form of V₂Ti₃O₉ and V_1.93Cr_0.07O₃ in CVTP and V₂TiO₅ in reduced CVTP. The V-bearing spinels on the grain boundaries with fragmentized and prismatic structure restrain the CS of CVTP. The CS of reduced CVTP decreases and RSI increases with increasing V₂O₅ additions. The V₂O₅ addition facilitates the aggregation and diffusion of metallic iron particles, and the shape of the metallic iron whiskers transform round dot to prismatic. The pores and intervals enlarge, and thickness of lamellar crystals thickens gradually with increasing V₂O₅ additions. The study could supply the theoretical and technical basis for the utilization of CVTP and other V-bearing ores with COG recyclable technology.

SEM images of reduced CVTP with V₂O₅ additions: (a) 0 mass%; (b) 2 mass%; (c) 4 mass%; (d) 6 mass%.