What is the reducing agent used by Hunter Process to produce titanium sponge?

Sodium.

In 1940, Luxembourg scientist W.J. Kroll used magnesium to reduce TiCl? to obtain pure titanium. Since then, the magnesium reduction method (also known as the Claure method) and the sodium reduction method (also known as the Hunter method) have become industrial methods for producing titanium sponge.

Titanium is a metallic chemical element with the chemical symbol Ti and atomic number 22. It is located in the fourth period and group IVB of the periodic table of chemical elements. Discovered by Gregor in 1791.