Titanium dioxide hydrate of a particular structure and process of manufacture thereof

Claim 2

δTitanium dioxide hydrate having an X-ray diffraction diagram taken by means of Cu-Kα rays which exhibits main peaks at 2θ=24.6±0.4° and 48±0.4°.

Claim 3

A mixture of titanium dioxide hydrates, which, calculated as TiO 2 and related to the total quantity of TiO 2 , contains more than 20% δ titanium dioxide hydrate having an X-ray diffraction diagram taken by means of Cu-Kα rays which exhibits main peaks at 2θ=24.6°±0.4° C. and 48°±0.4° C.

Claim 4

A mixture of titanium dioxide hydrates, which, calculated as TiO 2 and related to the total quantity of TiO 2 , contains more than 20% δ titanium dioxide hydrate having an X-ray diffraction diagram taken by means of Cu-Kα rays which exhibits main peaks at 2θ=24.6°±0.4° C. and 48°±0.4° C.

Claim 5

A process for producing δ titanium dioxide hydrate having an X-ray diffraction diagram taken by means of Cu-Kα rays which exhibits main peaks at 2θ=24.6°±0.4° and 48°±0.4°, and mixtures of titanium dioxide hydrates containing at least 20% of said δ titanium dioxide hydrate which comprises: hydrolyzing a titanium sulfate solution by heating to form colloidal δ titanium dioxide hydrate, said solution containing up to 150 g/l TiO 2 , and having a molar ratio of TiO 2 to free sulphuric acid between 1:1 and 1:2, and a bivalent iron content between 0 and 1 gram Fe per gram TiO 2 ; removing the colloidal δ titanium dioxide hydrate by flocculation by the adding of a monobasic acid or its salt; and separating the flocculated δ titanium dioxide hydrate from the solution.

Claim 6

A process for producing δ titanium dioxide hydrate having an X-ray diffraction diagram taken by means of Cu-Kα rays which exhibits main peaks at 2θ=24.6°±0.4° and 48°±0.4°, and mixtures of titanium dioxide hydrates containing at least 20% of said δ titanium dioxide hydrate which comprises: hydrolyzing a titanium sulfate solution by heating to form colloidal δ titanium dioxide hydrate, said solution containing up to 150 g/l TiO 2 , and having a molar ratio of TiO 2 to free sulphuric acid between 1:1 and 1:2, and a bivalent iron content between 0 and 1 gram Fe per gram TiO 2 ; removing the colloidal δ titanium dioxide hydrate by flocculation by the adding of a monobasic acid or its salt; and separating the flocculated δ titanium dioxide hydrate from the solution.

Claim 7

A process for preparing δ titanium dioxide hydrate and mixtures of titanium dioxide hydrates containing at least 20% δ titanium dioxide hydrate wherein said δ titanium dioxide hydrate has an X-ray diffraction diagram taken by means of Cu-Kα rays which exhibits main peaks at 2θ=24.6°±0.4° and 48°±0.4°, which comprises: hydrolyzing a titanium sulfate solution by heating in the presence of nuclei of titanium dioxide hydrate having an X-ray diffraction diagram taken by means of Cu-Kθ rays which exhibit main peaks at 2θ=24.6°±0.4° and 48°±0.4° to form colloidal δ titanium dioxide hydrate, said solution containing 120 to 250 g/l TiO 2 , having a molar ratio of TiO 2 to free sulfuric acid between 1:1 and 1:2 and a bivalent iron content between 0 and 1 gram Fe per gram TiO 2 ; removing the colloidal δ titanium dioxide hydrate by flocculation by the addition of a monobasic acid or its salt; and separating the flocculated δ titanium dioxide hydrate together with precipitated titanium dioxide hydrate consisting essentially of anatase hydrate from the solution.

Claim 8

A process for preparing δ titanium dioxide hydrate and mixtures of titanium dioxide hydrates containing at least 20% δ titanium dioxide hydrate wherein said δ titanium dioxide hydrate has an X-ray diffraction diagram taken by means of Cu-Kα rays which exhibits main peaks at 2θ=24.6°±0.4° and 48°±0.4°, which comprises: hydrolyzing a titanium sulfate solution by heating in the presence of nuclei of titanium dioxide hydrate having an X-ray diffraction diagram taken by means of Cu-Kθ rays which exhibit main peaks at 2θ=24.6°±0.4° and 48°±0.4° to form colloidal δ titanium dioxide hydrate, said solution containing 120 to 250 g/l TiO 2 , having a molar ratio of TiO 2 to free sulfuric acid between 1:1 and 1:2 and a bivalent iron content between 0 and 1 gram Fe per gram TiO 2 ; removing the colloidal δ titanium dioxide hydrate by flocculation by the addition of a monobasic acid or its salt; and separating the flocculated δ titanium dioxide hydrate together with precipitated titanium dioxide hydrate consisting essentially of anatase hydrate from the solution.

Claim 9

Process according to claims 3 or 4, characterized in that the titanium dioxide hydrate, which after the addition of the monobasic acid or its salts is present in the solution in a flocculated form, is removed and washed and then neutralized with alkali or ammonia and once more washed and/or dried.

Claim 10

Process in accordance with claims 3 or 4, characterized in that the titanium dioxide hydrate, which after the addition of the monobasic acid or its salts is present in the solution in a flocculated form, is thickened by sedimentation before being separated from the solution.

Claim 11

Process according to claims 3 or 4, characterized in that, before separation of the titanium dioxide hydrate which after the addition of a monobasic acid or its salts is present in the solution in a flocculated form, a flocculant is added.

Claim 12

Process according to claims 3 or 4, characterized in that, after its separation from the solution, the titanium dioxide hydrate or the titanium dioxide hydrate mixture is granulated.

Claim 13

Process in accordance with claims 3 or 4, characterized in that, solid inorganic or organic substances insoluble in acids are added to the titanium dioxide hydrate or the titanium dioxide hydrate mixture at a quantity of up to 70% by weight related to the resulting total mixture and that the total mixture thus obtained is then dried.

Claim 14

The process of claim 3 or 4 wherein precipitated titanium dioxide hydrate consisting essentially of anatase hydrate is removed from the hydrolyzed solution prior to removing the colloidal δ titanium dioxide hydrate by flocculation.

Claim 15

The process of claim 3 or 4 wherein the monobasic acid or its salt is added to the solution in amounts of 1.5 to 8 moles/liter.

Claim 16

The process of claim 3 or 4 wherein the separated material is washed with water to remove iron and other impurities.

Claim 17

The process of claim 3 or 4 wherein hydrolysis of the titanium sulfate solution is conducted in the presence of a trivalent titanium as a reductant.