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以新疆磁铁精矿为原料,采用一步法直接还原,研究高强度、高还原性预热球团的制备及煤基直接还原的工艺。研究了实验室转鼓模拟回转窑装置中直接还原铁的生产工艺。讨论了配碳比、反应温度、反应时间等工艺参数对金属化率、脱硫率等回转窑直接还原铁的主要质量指标的影响,提出了本试验原料条件下,回转窑生产直接还原铁的最佳工艺参数。研究结果表明,对于铁品位为64.39%(质量分数,余同)的新疆磁铁精矿,将预热球团在1 025℃还原70 min,得到直接还原铁(DRI)的质量指标为:金属铁的质量分数大于93%,金属化率达到95.48%~97.25%,硫的质量分数小于0.010%。与传统的预热-高温氧化-高温还原煤基回转窑直接还原工艺相比,“一步法”省去了高温氧化这一高能耗(1 150~1 300℃)工序,且还原所得产品结构完整。
Taking Xinjiang magnetite concentrate as raw material, the one-step direct reduction was used to study the preparation of high strength and highly reducing preheated pellets and the coal-based direct reduction process. The production technology of DRI in laboratory rotary kiln simulation rotary kiln was studied. The effects of process parameters such as carbon ration, reaction temperature and reaction time on the main quality indexes of direct reduction iron in rotary kiln such as metallization rate and desulfurization rate are discussed. It is proposed that the production of direct reduction iron Good process parameters. The results show that for Xinjiang magnetite concentrates with iron grade of 64.39% (mass fraction), the preheated pellets were reduced at 1025C for 70 min to obtain the quality index of direct reduced iron (DRI) as follows: metallic iron The mass fraction is more than 93%, the metallization rate is 95.48% ~ 97.25%, and the sulfur content is less than 0.010%. Compared with the traditional preheating-high temperature oxidation-high temperature reduction coal-based rotary kiln direct reduction process, “one-step method” eliminates the high-energy oxidation (1 150 ~ 1 300 ℃) process of high temperature oxidation and reduces the resulting product Structure is complete.