Process for the manufacture of titanium dioxide

Claim 2

A process as defined in claim 1 in which said titanium tetrachloride is introduced into said reaction zone through an inlet in which the downstream face of said inlet extends towards said axis at an angle within the range of from about 25* to 90* with respect to said axis.

Claim 3

A process as defined in claim 1 in which said titanium tetrachloride and oxidizing gas are introduced into said reaction zone which has an entrance portion tapering in an upstream direction at an angle of from about 1* to 30* and a length equal to about one to 25 times its diameter at its entrance end.

Claim 4

A process as defined in claim 1 in which said titanium tetrachloride is introduced into a distributing chamber disposed about said inlet for the titanium tetrachloride.

Claim 5

A process as defined in claim 1 in which said oxidizing gas is introduced into an annular distributing chamber disposed in operative communication with the supply conduit for the oxidizing gas through a circumferentially extending opening.

Claim 6

A process as defined in claim 1 in which a combustible gas is introduced into the downstream end portion of the supply conduit for the oxidizing gas.

Claim 7

A process as defined in claim 1 in which the surface of the reaction zone downstream of said inlet for the titanium tetrachloride is cooled.

Claim 8

A process as defined in claim 1 in which inert particulate refractory material is introduced through venturi nozzle means mounted coaxially within said supply conduit and is delivered upon those surfaces of the reaction zone and the oxygen supply conduit that are adjacent to said inlet for the titanium tetrachloride.

Claim 9

A process as defined in claim 1 in which inert particulate material is introduced through a nozzle into the upstream end of said supply conduit for the oxidizing gas and against a deflector located within said conduit and is deflected towards the surface of said conduit.

Claim 10

In a process for the vapor-phase oxidation of titanium tetrachloride in an elongated titanium dioxide-forming reaction zone provided with an inlet for the introduction of preheated oxidizing gas, an inlet for the introduction of preheated titanium tetrachloride, and an entrance portion, said for the introduction of said oxidizing gas comprising a supply conduit, the downstream end of which is spaced from the entrance of said reaction zone to define a circumferentially extending inlet which comprises said inlet for the preheated titanium tetrachloride, the improvements which comprise: providing said preheated titanium tetrachloride with a downstream component of velocity by passing said titanium tetrachloride into said reaction zone at a velocity of at least 50 feet per second through said titanium tetrachloride inlet which is provided with an upstream face which extends towards the axis of the reaction zone at an angle within the range of from about 15* to 165* with respect to said axis and a downstream face extending towards said axis in a manner such that the faces converge with one another towards the axis of said reaction zone and the supply conduit for the oxidizing gas terminates in a tapered section, providing an established flow of saId preheated oxidizing gas in said supply conduit before said oxidizing gas is introduced into said reaction zone by passing said gas, at a velocity of at least 50 feet per second, through a supply conduit having a diameter at its downstream end no greater than the diameter of the entrance portion of said reaction zone and the downstream end portion of said conduit over a length equal to at least five times the diameter of its downstream end having a straight axis, being coaxial with the reaction zone and being substantially nondivergent in the direction of flow of the oxidizing gas, reacting said titanium tetrachloride and said oxidizing gas in said reaction zone to produce titanium dioxide, and recovering said titanium dioxide.

Claim 11

In a process for the vapor-phase oxidation of titanium tetrachloride in an elongated titanium dioxide-forming reaction zone provided with an inlet for the introduction of preheated oxidizing gas, an inlet for the introduction of preheated titanium tetrachloride, and an entrance portion, said inlet for the introduction of said oxidizing gas comprising a supply conduit, the downstream end of which is spaced from the entrance portion of said reaction zone to define a circumferentially extending inlet which comprises said inlet for the preheated titanium tetrachloride, the improvements which comprise: providing said preheated titanium tetrachloride with a downstream component of velocity by passing said titanium tetrachloride into said reaction zone at a velocity of at least 50 feet per second through said titanium tetrachloride inlet which is provided with an upstream face extending in a downstream direction toward the axis of the reaction zone at an angle within the range of from about 15* to 80* with respect to said axis and a downstream face extending towards the axis of the reaction zone in such manner that the angle between it and normal to the axis is at least 10* less than the angle between the upstream face and the normal to said axis, providing an established flow of said preheated oxidizing gas in said supply conduit before said oxidizing gas is introduced into said reaction zone by passing said gas, at a velocity of at least 50 feet per second, through a supply conduit having a diameter at its downstream end no greater than the diameter of the entrance portion of said reaction zone and the downstream end portion of said conduit reaction a length equal to at least five times the diameter of its downstream end having a straight axis, being coaxial with the reaction zone and being substantially nondivergent in the direction of flow of the oxidizing gas, reacting said titanium tetrachloride and said oxidizing gas in said reaction zone to produce titanium dioxide, and recovering said titanium dioxide.

Claim 12

In a process for the vapor-phase oxidation of titanium tetrachloride in an elongated titanium dioxide-forming reaction zone provided with an inlet for the introduction of preheated oxidizing gas, an inlet means for the introduction of preheated titanium tetrachloride, and an entrance portion, said inlet for the introduction of said oxidizing gas comprising a supply conduit, the downstream end of which is spaced from the entrance portion of said reaction zone to define a circumferentially extending inlet which comprises said inlet for the preheated titanium tetrachloride, the improvements which comprise: providing said preheated titanium tetrachloride with a downstream component of velocity by passing said titanium tetrachloride into said reaction zone at a velocity of at least 50 feet per second through said titanium tetrachloride inlet which is provided wit an upstream face extending towards the axis of said conduit and reaction zone at an angle within the range of from about 15* to 165* with respect to said axis and a downstream face extending towards said axis at an angle within the range of about 15* to 165* with respect to said axis, provided that when said upstream and downstream faces extend toward the axis of the reaction zone at an angle greater than 80* with respect to said axis the supply conduit for the oxidizing gas terminates in a tapered section, providing an established flow of said preheated oxidizing gas in said supply conduit before said oxidizing gas is introduced into said reaction zone by passing said gas at a velocity of at least 50 feet per second, through a supply conduit having a diameter at its downstream end no greater than the diameter of the entrance portion of said reaction zone and the downstream end portion of said conduit over a length equal to at least five times the diameter of its downstream end having a straight axis, being coaxial with the reaction zone and being substantially nondivergent in the direction of flow of the oxidizing gas, directing inert particulate refractory material through a venturi nozzle upon the surfaces of the reaction zone and the oxygen supply conduit that are adjacent to said inlet for the titanium tetrachloride, said nozzle being provided with a movable coaxial conical member spacially mounted downstream from the mouth of the venturi and adapted to deflect the particulate material outwardly, reacting said titanium tetrachloride and said oxidizing gas in said reaction zone to produce titanium dioxide, and recovering said titanium dioxide.

Claim 13

A process as defined in claim 1 in which said titanium tetrachloride and said oxidizing gas are separately preheated to such a degree that when they are introduced into said reaction zone they have a calculated mixed gas temperature of at least 800* C.

Claim 14

A process as set forth in claim 1 in which there is introduced into the reaction zone a quantity of water vapor within the range of from about 0.00005 to 0.025 parts per part of titanium tetrachloride vapor introduced into the reaction zone.

Claim 15

A process as set forth in claim 1 in which aluminum chloride is introduced into the reaction zone in an amount sufficient to form from about 0.2 to about 10 percent aluminum oxide based on the weight of titanium dioxide produced.