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熔盐电解法是制备难熔金属及其合金的一种有效方法。以钛铁矿精矿与碳粉混合、模压成型,在氩气保护下,分别于1173,1273和1373 K进行一定时间的碳热还原,制备成含有单质铁微粒的铁-钛氧化物电极作为阴极,在673 K的Li Cl-KCl低温熔盐中进行电解还原获得钛铁合金。在1173,1273和1373 K碳热还原反应3 h所得铁-钛氧化物电极中,单质铁的还原率分别为30.1%,80.1%和82.7%;电极的电导率分别为3.14,8.06和10.87 S·m-1;开口孔隙率分别为46.1%,50.9%和35.2%。其中在1173 K制备的铁-钛氧化物电极中,单质铁呈粒度较小的圆球状,分布较为均匀,但铁的还原率偏低,且强度较低;在1373 K制备的电极中单质铁发生了明显偏析、富集,汇聚成带状,开口孔隙率显著降低,不利于熔盐电解质向电极内部扩散和浸润;而在1273 K制备的电极中单质铁呈圆球状,粒度为2~6μm,分布较为均匀,且开口孔隙率最大,该电极在673 K的KCl-Li Cl低温熔盐中能够电解还原获得钛铁合金,而且电解时通过电极的电流最大。
Molten salt electrolysis is an effective method to prepare refractory metals and their alloys. The ilmenite concentrate was mixed with the carbon powder, molded, and subjected to carbothermal reduction at 1173, 1273 and 1373 K for a certain time under the protection of argon to prepare an iron-titanium oxide electrode with iron oxide particles Cathode, in 673 K Li Cl-KCl low temperature molten salt electrolysis to obtain titanium-iron alloy. The reduction rates of elemental iron were 30.1%, 80.1% and 82.7% respectively in the iron-titanium oxide electrode obtained at 3 h after 1173, 1273 and 1373 K carbothermal reduction. The conductivities of the electrodes were 3.14, 8.06 and 10.87 S · M-1; the open porosity was 46.1%, 50.9% and 35.2%, respectively. Among the iron-titanium oxide electrodes prepared at 1173 K, the elementary iron showed a spherical shape with a relatively small particle size and a uniform distribution, but the iron reduction rate was low and the strength was low. In the electrode prepared at 1373 K, the elemental iron The segregation, enrichment and banding of ribbons were observed, and the porosity of opening was significantly decreased, which was not conducive to the diffusion and infiltration of molten salt electrolyte into the electrode. In the electrode prepared at 1273 K, the iron was spherical with a particle size of 2 ~ 6μm , The distribution is more uniform, and the porosity of the opening is the largest. The electrode can be electrolytically reduced to obtain the ferro-titanium alloy in the KCl-LiCl low-temperature molten salt of 673 K, and the current through the electrode is maximized during electrolysis.