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US 2008/0159933 A1Published application
Processes for producing titanium dioxide
AssigneeE. I. DuPont de Nemours and Company
InventorsDAVID RICHARD CORBIN, THOMAS PAUL GRIFFIN, KEITH W. HUTCHENSON, SHENG LI, MARK BRANDON SHIFLETT, CARMINE TORARDI, JOSEPH J. ZAHER
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Abstract
Provided are processes for the production of titanium dioxide from ilmenite. In these processes, ilmenite is digested with aqueous ammonium 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.
Claims34
A process comprising:
- a) digesting ilmenite ore with aqueous ammonium hydrogen oxalate to form a leachate and an iron-rich precipitate;
- b) separating said leachate from said iron-rich precipitate;
- c) hydrolyzing said leachate with ammonia or ammonium hydroxide to form titanyl hydroxide and an oxalate-rich solution;
- d) separating said titanyl hydroxide from said oxalate-rich solution;
- e) washing said titanyl hydroxide with a material selected from the group consisting of water, aqueous ammonium oxalate and ammonium hydroxide to form low oxalate titanyl hydroxide;
- and
- f) crystallizing titanium dioxide from said low oxalate titanyl hydroxide.
4 more elements
A process comprising:
- a) digesting ilmenite ore with aqueous ammonium hydrogen oxalate to form a first leachate and an iron-rich precipitate;
- b) separating said first leachate from said iron-rich precipitate;
- c) optionally, adding a reducing agent to said first leachate to form a second iron-rich precipitate and a second leachate and separating said second iron-rich precipitate from said second leachate;
- d) hydrothermally crystallizing said first or second leachate in an autoclave for between 1 h and 24 h 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 ammonium hydrogen oxalate to form a leachate and an iron-rich precipitate;
- b) separating said leachate from said iron-rich precipitate;
- adding a reducing agent to said leachate to form a second iron-rich precipitate and a reduced leachate;
- c) separating said second iron-rich precipitate from said reduced leachate;
- d) hydrolyzing said reduced leachate with ammonium hydroxide to form titanyl hydroxide;
- and
- e) hydrothermally crystallizing said titanyl hydroxide to form titanium dioxide and a diammonium oxalate solution.
4 more elements
Dependencies are inferred from the claim text.