基于气基直接还原-熔分的硼铁矿高效利用新工艺

实验室条件下,以含硼铁精矿为原料制备氧化球团,对含硼铁精矿气基竖炉直接还原-电炉熔分新工艺进行了研究.结果表明,含硼铁精矿是良好的造球原料,1 200℃下焙烧20 min后,成品球团抗压强度可达2 500 N以上,满足气基竖炉直接还原工艺要求.在H2与CO体积比大于2/5且温度在850~1 000℃条件下,含硼铁精矿氧化球团还原率达到95%的时间为15~60 min,还原膨胀率不高于15%.在高温下电热熔化DRI后硼和铁可以高效分离,硼、铁收得率均可达到98%以上,富硼渣中B2O3的质量分数在21%以上,活性可达89%左右,是"一步法"生产硼酸的优良原料.含硼铁精矿气基竖炉直接还原电炉熔分新工艺可以实现硼铁高效分离和清洁利用.

New Efficient Process Utilizing Ludwigite on Gas-based Shaft Furnace Direct Reduction and Electric Furnace Smelting Separation

In this work， oxide pellet was prepared from boron-bearing iron concentrate. A new process that the boron-bearing iron concentrate was directly reduced and separated by shaft furnace and electric furnace smelting， respectively. The corresponding reduction and separation theories were discussed. The results showed that boron-bearing iron concentrate pelletization can fully meet the requirements of the gas-based shaft furnace direct reduction process. After boasting at 1200℃ for 20minutes， the compressive strength of the finished pellet is higher than 2500N. When the H₂ to CO ratio is higher than 2/5 and the temperature is between 850℃ to 1000℃， the time for reducing 95% of the boron-bearing iron concentrate is between 10min to 60min and the expansion ratio is less than 15%. Boron and iron can be efficiently separated from DRI by electric furnace at 1500℃. The yields of both boron and iron can achieve up to 98%. The activity and the mass fraction of B₂O₃ in the slag can reach 89% and 21%， respectively， suggesting that this kind of slag can be used as high quality raw materials for the one-step boric acid production. The new process can efficiently separate and cleanly utilize boron-bearing iron concentrate.