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基于碱度匹配的高比例钒钛球团制备及炉料结构设计

Preparation of high-proportion vanadium-titanium pellet and design of burden structure based on basicity matching

  • 摘要: 为提高钒钛球团在高炉炉料中的配比,并缓解高碱度烧结矿匹配高球团比时带来的高温性能劣化问题,提出了基于碱度匹配的高比例钒钛球团炉料结构设计思路。以维持入炉品位、炉渣碱度、w(MgO)/w(Al2O3)及热制度基本稳定为边界条件,制备不同碱度的熔剂性钒钛球团,并系统评价其冷态强度、还原粉化、还原膨胀、还原性及综合炉料软熔滴落性能。结果表明,随球团碱度提高(0.13提高至0.62),球团中CaO质量分数由0.32%增加至2.13%,抗压强度提高至2 714.6 N/个;当球团碱度为0.62时,还原粉化率(IRD<3.15 mm)降低至1.60%,表现出较好的中低温还原粉化性能,然而,还原膨胀率(IRS)恶化,达到17.84%。单一钒钛球团料层的软熔滴落性能随碱度升高而劣化,透气性指数(S值)由340.60 kPa·℃增加至2 000.27 kPa·℃;但在碱性烧结矿、酸性烧结矿、白马球团与钒钛球团组成的综合炉料中,烧结矿与球团矿之间存在显著的协同造渣作用。当总球团比例为59%、钒钛球团碱度为0.47时,综合炉料软化区间为75 ℃,熔融滴落区间为130 ℃,S值最低,为1 372.91 kPa·℃,表明软熔带透气性较优。配矿测算表明,在维持炉渣制度基本不变的条件下,球团比例(质量分数)可由55%提高至61%,钒钛矿比例提高3.44%,炉渣TiO2质量分数提高至23.15%,配矿成本吨铁降低38.10元。研究结果可为高比例钒钛球团炉料结构优化及钒钛磁铁矿低成本、高效利用提供参考。

     

    Abstract: To increase the proportion of vanadium-titanium pellets in blast furnace burden and alleviate the deterioration of high-temperature performance caused by matching high pellet ratios with high-basicity sinter, a burden design strategy based on basicity matching was proposed. Fluxed vanadium-titanium pellets with different basicities were prepared under the boundary conditions of maintaining the iron grade, slag basicity, w(MgO)/w(Al2O3) ratio, and thermal regime. Their cold strength, reduction disintegration, reducibility, and softening-melting behavior were systematically evaluated. The results show that, with increasing pellet basicity (from 0.13 to 0.62), the mass fraction of CaO in the pellet increases from 0.32% to 2.13%, and the compressive strength reaches 2 714.6 N per pellet. At a pellet basicity of 0.62, the reduction degradation index (IRD<3.15 mm) decreases to 1.60%, indicating good low- and medium-temperature the reduction degradation resistance. However, the reduction swelling index (IRS) reaches 17.84%. For a single pellet bed, the softening-melting behavior deteriorates with increasing basicity, and the gas permeability index (S value) increases from 340.60 to 2 000.27 kPa·℃. In the composite burden composed of basic sinter, acid sinter, Baima pellets, and vanadium-titanium pellets, however, a clear synergistic slagging effect occurs between sinter and pellets. At a total pellet ratio of 59% and a vanadium-titanium pellet basicity of 0.47, the composite burden exhibits the best high-temperature performance, with a softening interval of 75 ℃, a melting-dripping interval of 130 ℃, and the lowest S value of 1 372.91 kPa·℃. Ore-blending calculations indicate that, while maintaining the slagging regime, the pellet ratio can be increased from 55% to 61%, the vanadium-titanium ore proportion increases by 3.44 percentage points, the mass fraction of TiO2 in the slag is increased to 23.15%, and the ore-blending cost decreases by 38.10 yuan/t(hot metal). These results provide a basis for optimizing high-proportion vanadium-titanium pellet burden and for the low-cost and efficient utilization of vanadium-titanium magnetite.

     

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