The invention provides a method for the Industrial purification of a titanium feed stream of purity P1 , by the formation of a titanium-double-salt precipitate of purity P2 and a titanium solution with purity P3, wherein P2>P1 >P3, the method comprising the steps of: i. forming, from the feed, a medium comprising water, titanium ion, a cation selected from the group consisting of ammonium, cations of alkali metals, protons and a combination thereof, and an anion selected from the group consisting of OH, SO4, HSO4, halides and a combination thereof, which formed medium is further characterized by the presence of (a) a double-salt precipitate comprising titanium ion, at least one of the cations and at least one of the anions; and (b) a titanium solution; and wherein the concentration of the anion in the titanium solution is higher than 15% and the ratio between the concentrations of the cation and the anion in the titanium solution is higher than 0.2 and lower than 1.6; and ii. separating at least a portion of the precipitate from the solution.