Process of preparing titanates
Processes of preparing metal titanate from one or more metal compounds, and a product provided by the process. In one embodiment, sodium titanate and an ionic metal compound are mixed into an aqueous mixed slurry, which is allowed to react into metal titanate at the boiling point of the mixed slurry or below, by mixing it at normal pressure and in a normal gaseous atmosphere. After this, the metal titanate product is optionally washed, and/or filtered and dried.
1. A process of preparing metal titanate from one or more metal compounds, comprising the steps of:
a) mixing sodium titanate and an ionic metal compound(s) at ambient pressure and in an ambient gaseous atmosphere to form an aqueous mixed slurry;
b) allowing the mixed slurry to react, precipitate and form a crystalline metal titanate product at ambient pressure and in an ambient gaseous atmosphere at or below a boiling point of the mixed slurry and
c) washing and/or filtering and drying the metal titanate product.
2. The process according to claim 1 , wherein said mixed slurry is allowed to react into the metal titanate product at a temperature of 100° C. or below.
3. The process according to claim 1 , wherein the ionic metal compound(s) comprises a metal cation selected from the group consisting of Al, Bi, Fe, Hf, K, La, Mn, Ni, Pb, Zn, Zr and alkali earth metals.
4. The process according to claim 1 , wherein the ionic metal compound(s) comprises a metal cation comprising an alkali earth metal.
5. The process according to claim 1 , wherein the ionic metal compound(s) comprises a metal cation comprising Ba and/or Sr.
6. The process according to claim 1 , wherein the ionic metal compound(s) is a hydroxide or a carbonate.
7. The process according to claim 1 , wherein the ionic metal compound is an alkali earth metal hydroxide.
8. The process according to claim 1 , wherein the aqueous mixed slurry is allowed to react for 12 hours to precipitate and form the metal titanate product.
9. The process according to claim 1 , wherein the sodium titanate is in a form of an aqueous slurry.
10. The process according to claim 1 , further comprising the step of preparing the sodium titanate by reacting titanium dioxide with alkali to form a slurry of the sodium titanate.
11. The process according to claim 1 , further comprising the step of preparing the sodium titanate from an ilmenite concentrate by means of sulphuric acid, by hydrolyzing titanium dioxide hydrate, which is elutriated in water into a density of 300-400 g/l into a titanium dioxide hydrate slurry, which is boiled with alkali at a pH that is over 11 into a slurry of the sodium titanate, from which soluble sulphate salts are washed out and which is filtered.
12. The process according to claim 1 , further comprising a step where the sodium titanate is elutriated in water into a sodium titanate slurry at a density of 150-350 g/l.
13. The process according to claim 1 , wherein molar ratio of sodium titanate to ionic metal compound(s) is between 0.9 and 1.8.
14. The process according to claim 1 , wherein the metal titanate product is dried at a temperature of below 250° C. and, optionally, in a vacuum, to form a dried metal titanate product.
15. The process according to claim 14 , wherein the dried metal titanate product is further processed by calcining at a temperature of 950° C. or below.
16. A metal titanate product, prepared by the process according to claim 1 wherein the product has a crystal size less than 170 nm.