TITANIUM DIOXIDE
Prepared at the 76th JECFA (2012) and published in FAO JECFA Monographs 13 (2012), superseding specifications prepared at the 73rd JECFA (2010) and published in FAO JECFA Monographs 10 (2010). An ADI “not limited” was established at the 13th JECFA (1969).
SYNONYMS Titania; CI Pigment white 6; CI (1975) No. 77891; INS No. 171
DEFINITION Titanium dioxide is produced by either the sulfate or the chloride process. Processing conditions determine the form (anatase or rutile
structure) of the final product.
In the sulfate process, sulfuric acid is used to digest ilmenite (FeTiO3) or ilmenite and titanium slag. After a series of purification steps, the isolated titanium dioxide is finally washed with water, calcined, and micronized.
In the chloride processes, (a) titanium-containing mineral is reacted with chlorine gas under reducing conditions to form anhydrous titanium tetrachloride, which is subsequently purified and converted to titanium dioxide either by direct thermal oxidation or by reaction with steam in the vapour phase; (b) titanium-containing mineral is reacted with concentrated hydrochloric acid to form a solution of titanium tetrachloride, which is further purified and hydrolysed to get titanium dioxide. The compound is filtered, washed and calcined.
Commercial titanium dioxide may be coated with small amounts of alumina and/or silica to improve the technological properties of the
product.
C.A.S. number 13463-67-7
Chemical formula TiO2
Formula weight 79.88
Assay Not less than 99.0% on the dried basis and on an aluminium oxide and silicon dioxide free basis.
DESCRIPTION White to slightly coloured amorphous powder
FUNCTIONAL USES Colour
