Process for manufacturing a stable titanyl sulfate solution

Claim 2

A process for preparing a stable titanyl sulfate solution, which comprises: (1) reacting a titaniferous bearing material in an amount between about 10% and about 400% above the stoichiometric amount of material necessary to react with sulfuric acid to provide titanyl sulfate with a dilute sulfuric acid solution having a concentration between about 25% and about 60% by weight, based upon the total weight of said solution, at a temperature below about 140° C.; (2) cooling the resulting reaction mixture to a temperature below about 110° C. without precipitating the titanyl sulfate to produce a reaction mixture containing dissolved titanyl sulfate; (3) diluting the reaction mixture containing titanyl sulfate with a sufficient amount of a diluent material selected from the group consisting of water, titanyl sulfate solution, and mixtures thereof, to produce a reaction mixture having the following properties in the absence of undissolved solids: an iron to titanium dioxide weight ratio of about 0.5-1.2:1.0, a titanium dioxide content of about 120 to about 180 grams per liter, a specific gravity of about 1.4 to about 1.8, and an active sulfuric acid to titanium dioxide mole ratio of about 1.4-1.9:1; (4) separating undissolved solids and obtaining a stable titanyl sulfate solution.

Claim 3

The process of claim 1 wherein the diluent is a titanyl sulfate solution having a weight ratio of iron to titanium dioxide of less than 0.4:1.0.

Claim 4

The process of claim 1 wherein the dilution is performed prior to separating the undissolved solids.

Claim 5

The process of claim 1 wherein dilution is performed by using said diluent materials at a temperature less than the temperature of the reaction mixture to inhibit hydrolytic nucleation of titanyl sulfate present in the reaction mixture.

Claim 6

A process for producing titanium dioxide from a titanyl sulfate solution, which comprises: (1) reacting a titaniferous bearing material in an amount between about 10% and about 400% above the stoichiometric amount of titaniferous bearing material necessary to react with sulfuric acid to provide titanyl sulfate with a dilute sulfuric acid solution having a concentraton between about 25% and about 60% by weight, based upon the total weight of said solution, at a temperature below about 140° C.; (2) cooling the resulting reaction mixture to a temperature below about 110° C. without precipitating titanyl sulfate to produce a reaction mixture containing dissolved titanyl sulfate; (3) diluting the reaction mixture containing titanyl sulfate with a sufficient amount of a diluent material selected from the group consisting of water, titanyl sulfate solution, and mixtures thereof to produce a reaction mixture having the following properties in the absence of undissolved solids, an iron to titanium dioxide weight ratio of about 0.7-1.1:1.0, a titanium dioxide content of about 120 to about 180 grams per liter, a specific gravity of about 1.4 to about 1.8, and an active sulfuric acid to titanium dioxide mole ratio of about 1.4-1.9:1.0; (4) separating undissolved solids from the reaction mixture to provide a solution of iron sulfate and titanyl sulfate; (5) removing iron sulfate from said solution of iron sulfate and titanyl sulfate to produce a solution of titanyl sulfate; (6) hydrolyzing said titanyl sulfate to provide a titanium dioxide hydrate, and spent sulfuric acid solution; (7) calcining said titanium dioxide hydrate to provide titanium dioxide; and (8) recovering titanium dioxide.

Claim 7

A process for producing titanium dioxide from a titanyl sulfate solution, which comprises: (1) reacting a titaniferous bearing material in an amount between about 10% and about 400% above the stoichiometric amount of titaniferous bearing material necessary to react with sulfuric acid to provide titanyl sulfate with a dilute sulfuric acid solution having a concentraton between about 25% and about 60% by weight, based upon the total weight of said solution, at a temperature below about 140° C.; (2) cooling the resulting reaction mixture to a temperature below about 110° C. without precipitating titanyl sulfate to produce a reaction mixture containing dissolved titanyl sulfate; (3) diluting the reaction mixture containing titanyl sulfate with a sufficient amount of a diluent material selected from the group consisting of water, titanyl sulfate solution, and mixtures thereof to produce a reaction mixture having the following properties in the absence of undissolved solids, an iron to titanium dioxide weight ratio of about 0.7-1.1:1.0, a titanium dioxide content of about 120 to about 180 grams per liter, a specific gravity of about 1.4 to about 1.8, and an active sulfuric acid to titanium dioxide mole ratio of about 1.4-1.9:1.0; (4) separating undissolved solids from the reaction mixture to provide a solution of iron sulfate and titanyl sulfate; (5) removing iron sulfate from said solution of iron sulfate and titanyl sulfate to produce a solution of titanyl sulfate; (6) hydrolyzing said titanyl sulfate to provide a titanium dioxide hydrate, and spent sulfuric acid solution; (7) calcining said titanium dioxide hydrate to provide titanium dioxide; and (8) recovering titanium dioxide.

Claim 8

The process of claim 5 wherein the titanyl sulfate solution employed for diluting the reaction mixture is a titanyl sulfate solution recovered after removing ferrous sulfate but prior to hydrolyzing said titanyl sulfate solution, said diluent having a weight ratio of iron to titanium dioxide less than 0.4:1.0.

Claim 9

The process of claim 5 wherein the dilution is performed prior to separating the undissolved solids.

Claim 10

The process of claim 5 wherein the dilution is performed by using said diluent materials at a temperature less than the temperature of the reaction mixture to inhibit hydrolytic nucleation of the titanyl sulfate present in the reaction mixture.