Rutile is the second most abundant

Rutile is the second most abundant mineral sand. Rutile found in primary rock cannot be extracted hence the deposits containing rutile sand can be mined meaning a reduced availability to the high concentration ore. Crude titanium dioxide (in the form of rutile or synthetic rutile) is purified via converting to titanium tetrachloride in the chloride process. In this process, the crude ore (containing at least 70% TiO2) is reduced with carbon, oxidized with chlorine to give titanium tetrachloride; i.e., carbothermal chlorination. This titanium tetrachloride is distilled, and re-oxidized in a pure oxygen flame or plasma at 1500–2000 K to give pure titanium dioxide while also regenerating chlorine.[19] Aluminium chloride is often added to the process as a rutile promotor; the product is mostly anatase in its absence. The preferred raw material for the chloride process is natural rutile because of its high titanium dioxide content.[20]

One method for the production of titanium dioxide with relevance to nanotechnology is solvothermal Synthesis of titanium dioxide.