How did Hans Goldschmidt produce pure chromium in 1898?

In 1898, the German chemist Hans Goldschmidt produced pure chromium through the aluminothermic reduction of chromium oxide.1

This method, often referred to as the aluminothermic process, involves reacting chromium oxide (Cr₂O₃) with finely divided aluminum powder. When this mixture is ignited in a refractory-lined container, the chemical reaction generates intense heat—often exceeding 2,000 °C (3,600 °F)—which effectively separates the chromium from the slag. This process remains a standard technique for producing chromium metal, typically yielding a product with a purity level between 97 and 99 percent.23