Process for the production of high-grade titanium dioxide by sulfate method
AssigneeBayer Aktiengesellschaft
InventorsGabriel Denecker, Werner Verhoeven, Joel Leuridan, Domien Sluyts
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Abstract
High-grade titanium dioxide is produced by (a) reacting ilmenite or titanium-containing slag with sulfuric acid, (b) dissolving the material from (a) with water or dilute sulfuric acid, (c) separating insolubles from (b) to obtain a black solution containing titanyl sulfate and foreign metal salts, extracting titanyl sulfate from the black liquor with sulfuric acid and an organic medium containing an organophosphorus compound, separating the foreign metal salts in an aqueous extract phase, recovering titanyl sulfate from the organic extract phase, and hydrolyzing the titanyl sulfate to titanium oxide hydrate.
Claims15
In the improved process for the production of high-grade titanium dioxide by the sulfuric acid digestion method wherein:
- (a) ilmenite, or titanium-containing slag is reacted with concentrated sulfuric acid,
- (b) the reaction product from (a) is dissolved in water or aqueous sulfuric acid,
- (c) the insoluble raw-material fraction is separated from the solution from (b) to recover a sulfuric-acid-containing titanylsulfate black solution rich in foreign metal salts, and
- (d) titanyl sulfate is hydrolyzed with subsequent separation of precipated titanium oxide hydrate followed by washing with water and drying the improvement comprises extracting titanyl sulfate from the black solution before the step (d) with an organic medium containing an organophosphorus compound of the formula
- R.sub.m (R.sup.1 O).sub.n P.dbd.O
- wherein
- R represents linear or branched alkyl groups,
- R.sup.1 represents alkyl groups as in R or aryl groups or alkyl substituted aryl groups
- m is an integer, 1, 2 or 3 and
- n is an integer, 1 or 2 or is zero
- with the proviso that the sum of m and n is 3 and the organophosphorus compound contains a total of at least 12 carbon atoms
- and contacting the organic medium before or during the extraction with a sulphuric acid solution or a metal salt containing sulphuric acid solution to produce a titanyl sulfate-rich organic phase and a foreign metals-rich aqueous phase, separating the organic phase from the aqueous phase and re-extracting titanyl sulfate from the organic phase with water or a dilute aqueous sulfuric acid or titanyl sulfate containing solution.
Dependencies are inferred from the claim text.