新型炼铝电极材料

New inert anode in aluminum electrolysis

研制了一种新型铝电解金属陶瓷惰性阳极,阳极基体由Fe Ni Co Al O构成。在电解温度960℃,氧化铝质量浓度为6.0%,阳极电流密度为1.0A/cm2,分子比为2.6的电解质中对其进行了10h的电解。电解过程平稳,电解铝产品纯度达到96%～99%,阳极气体中氧气的含量为98%,反电动势为2.45V,高于理论值0.25～0.35V。此阳极具备较好的导电性、抗氧化和耐腐蚀性。采用X射线衍射和电子探针微分析仪(EPMA)对电解后的阳极进行分析,发现阳极表面存在铁酸镍、铝酸铁等尖晶石型化合物,阳极表面下层为铝酸铁、钴酸镍等陶瓷相以及金属相;金属相和陶瓷相相互弥散分布构成结构致密的金属陶瓷层。

A new inert anode consisited of Fe-Ni-Co-Al-O was made for aluminum electrolysis. Electrolysis with this anode was conducted at 960 ℃ for 10 h in a cryolite-alunima electrolyte with CR2.6 and Al_2O_3 content 6%, the anode current density is 1.0 A/cm^2(100A). The purity of aluminum metal attained is in the interval of 96%～99%, and the anode gases analysed by an Orsat apparatus is 98%～99%. The back EMF value of the cell is 2.45 V at 960 ℃, which is about 0.250.35 V higher than the theoretical decomposition voltage of the above electrochemical reaction. X-ray diffraction and electron probe micro-analyzer results on the anode after electrolysis show that there are NiFe_2O_4, FeAl_2O_4 at the surface of this anode, and there are FeAl_2O_4, NiCo_2O_4 and Ni, Fe metals under the surface of this anode, metal phases and ceramic phases are well dispersed forming compact metal ceramic structure.