Both Gregor and Klaproth worked with titanium compounds. The 1st substantial isolation of just about pure titanium was accomplished in 1875 by Kirillov in Russia. Isolation in the pure metal wasn't shown until 1910 when Matthew Hunter and his associates reacted titanium tetrachloride with sodium in the heated steel bomb. https://glasslinedsteelpipe58135.wikibyby.com/1573858/considerations_to_know_about_chemical_formula_for_potassium_silicate