Eliminating nonuniform geometric effects for long-term stable electrochemical extraction of high-purity titanium.

Electrorefining of low-grade titanium is one of the strategies for achieving high-purity titanium. However, the presence of nonuniform geometric effects would be induced to impact the nonuniform geometric distribution of overpotential, leading to impurity dissolution and nonuniform Ti deposition. Here, in situ high-temperature characterizations on the molten salt electrorefining process are applied to establish an anodic dissolution principle for quantitatively evaluating nonuniform geometric effects of electrode. For eliminating the nonuniform geometric effects, coaxial anode-cathode configurations are designed to promote the nonuniform anodic dissolution and nonuniform cathodic deposition. Consequently, the geometric uniformity of titanium products on the cathodes is substantially enhanced, and thus, long-term stable electrorefining process (~12 hours, ~330% increment compared to the electrode of reference configuration) and highly purified titanium products (99.2%) are achieved.