铁酸锌还原-氧化选择性分解行为研究

Selective Decomposition Behavior of Zinc Ferrite by Reduction and Oxidation

为了解决铁酸锌还原分解后锌、铁分离难题,提出一种强化铁酸锌选择性分解新工艺:先通过还原焙烧将铁酸锌分解为氧化锌和铁氧化物,然后冷却至低温,在CO_2气氛下利用氧化亚铁在低温下化学活性强、不稳定的特性,将过还原的氧化亚铁转化为磁性四氧化三铁。研究结果表明,铁酸锌强化还原分解的最佳条件为:CO浓度20%、还原温度750℃、V_(CO)/(V_(CO)+V_(CO_2))比67%、焙烧时间90 min,该条件下铁酸锌分解率达到96.63%;然后对铁酸锌分解产物进行磁化焙烧,最佳磁化焙烧条件为:氧化温度600℃、氧化时间75 min、CO_2气体流量1.2 L/min,此条件下焙烧产物比磁化率从未磁化前的5.30×10^(-11)m^3/kg增大至1.17×10^(-10)m^3/kg。

In view of the difficulty in the zinc⁃iron separation after the reduction and decomposition of zinc ferrite,a new process for enhancing the selective decomposition of zinc ferrite was proposed.Firstly,the zinc ferrite is decomposed into zinc oxide and iron oxide by reduction roasting,and then cooled down to a low temperature.The over⁃reduced ferrous oxide can be converted into magnetic ferroferric oxide by taking advantage of ferrous oxide with the characteristics of strong chemical activity and unstability at low temperatures under the CO2 atmosphere.The research results show that under the optimal conditions for the enhanced reduction and decomposition of zinc ferrite,including CO concentration of 20%,reduction temperature of 750℃,ratio of VCO/(VCO+VCO2)at 67%,roasting time of 90 min,the decomposition rate of zinc ferrite can reach 96.63%.Then,after decomposition of zinc ferrite,the generated products are subjected to the magnetizing roasting process under the following optimal conditions:oxidation at 600℃for 75 min,with CO2 gas flow rate at 1.2 L/min.It is shown that the specific susceptibility of roasted product increases from 5.30×10^(-11) m^3/kg to 1.17×10^(-10)m^3/kg compared with the products before magnetization.