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US 7,678,350 B2Granted
Processes for producing titanium dioxide
AssigneeE. I. Du Pont de Nemours and Company
InventorsDavid Richard Corbin, Scott N. Hutchison
Life of this patent
Estimating the term…
Abstract
Provided are processes for the production of titanium dioxide from ilmenite. In these processes, ilmenite is digested with aqueous trimethylammonium hydrogen oxalate. Iron from the ilmenite precipitates as a hydrated iron oxalate and is removed by filtering, leaving a titanium-rich solution. The titanium-rich solution can be further processed to form titanium dioxide.
Claims15
A process comprising:
- a) digesting ilmenite ore with aqueous trimethylammonium hydrogen oxalate to form a leachate and an iron-rich precipitate;
- b) separating said leachate from said iron-rich precipitate to form a separated leachate and a separated iron-rich precipitate;
- c) hydrolyzing said separated leachate with trimethylamine or aqueous trimethylamine to form titanyl hydroxide and an oxalate-rich solution;
- d) separating said titanyl hydroxide from said oxalate-rich solution to form a separated titanyl hydroxide;
- e) washing said separated titanyl hydroxide with a material selected from the group consisting of water, trimethylamine and aqueous trimethylamine to form washed titanyl hydroxide;
- and
- f) crystallizing titanium dioxide from said washed titanyl hydroxide.
4 more elements
A process comprising:
- a) digesting ilmenite ore with aqueous trimethylammonium hydrogen oxalate to form a first leachate and an iron-rich precipitate;
- b) separating said first leachate from said iron-rich precipitate to form a separated first leachate and a separated iron-rich precipitate;
- c) optionally, adding a reducing agent to said separated first leachate to form a second iron-rich precipitate and a second leachate and separating said second iron-rich precipitate from said second leachate to form a separated second iron-rich precipitate and a separated second leachate;
- d) hydrothermally crystallizing said separated first or second leachate in an autoclave for a period of one hour to 24 hours to form titanium dioxide and a hydrothermally treated solution;
- and
- e) separating said titanium dioxide from said hydrothermally treated solution.
3 more elements
A process comprising:
- a) digesting ilmenite ore with aqueous trimethylammonium hydrogen oxalate to form a leachate and an iron-rich precipitate;
- b) separating said leachate from said iron-rich precipitate to form a separated leachate and a separated iron-rich precipitate;
- adding a reducing agent to said separated leachate to form a second iron-rich precipitate and a reduced leachate;
- c) separating said second iron-rich precipitate from said reduced leachate of (b) to form a separated reduced leachate and a separated second iron-rich precipitate;
- d) hydrolyzing said separated reduced leachate with aqueous trimethylamine to form titanyl hydroxide;
- and
- e) hydrothermally crystallizing said titanyl hydroxide to form titanium dioxide and a di(trimethylammonium) oxalate solution.
4 more elements
Dependencies are inferred from the claim text.