US 7,029,648 B2 · Process for making durable rutile titanium dioxide pigment by vapor phase deposition of surface treatment

Abstract

The present invention relates to a process for making durable titanium dioxide pigment by vapor phase deposition of surface treatments on the titanium dioxide particle surface by reacting titanium tetrachloride vapor, an oxygen containing gas and aluminum chloride in a plug flow reactor to form a product stream containing titanium dioxide particles; and introducing silicon tetrachloride into the reactor at a point down stream of the point where the titanium tetrachloride and oxygen were contacted and where at least 97% of the titanium tetrachloride has been converted to titanium dioxide or where the reaction temperature is no greater than about 1200° C., and preferably not more than about 1100° C.

Claims30

Dependent claims

A process for making durable rutile titanium dioxide pigment by vapor phase deposition of surface treatments on the titanium dioxide pigment particle surface, the process comprising the steps of:

(a) reacting titanium tetrachloride vapor and aluminum chloride and at least a stoichiometric amount of oxygen in a plug flow reactor to form a product stream containing more than 99% rutile titanium dioxide particles;
(b) introducing silicon tetrachloride into the reactor at one or more points downstream of the point where the titanium tetrachloride, aluminum chloride, and oxygen were contacted and where at least 97% of the titanium tetrachloride has been converted to titanium dioxide to form the durable rutile titanium dioxide pigment wherein at least 85% of the titanium dioxide pigment particles are completely covered by a uniform layer formed from a mixture of amorphous aluminum oxide and amorphous silicon dioxide;
and
(c) withdrawing from the reactor the durable rutile titanium dioxide pigment, whereby the silicon tetrachloride introduced in (b) does not influence crystal phase or pigment carbon black undertone.

1 more element

A durable rutile titanium dioxide pigment, the pigment produced by:

(a) reacting titanium tetrachloride vapor and aluminum chloride and at least a stoichiometric amount of oxygen in a plug flow reactor to form a product stream containing more than 99% rutile titanium dioxide particles;
and
(b) introducing silicon tetrachloride into the reactor at one or more points downstream of the point where the titanium tetrachloride, aluminum chloride and oxygen were contacted and where at least 97% of the titanium tetrachloride has been converted to titanium dioxide to form the durable rutile titanium dioxide pigment wherein at least 85% of the pigment particles are completely covered by a uniform layer formed from a mixture of amorphous aluminum oxide and amorphous silicon dioxide;
and
(c) withdrawing from the reactor the durable rutile titanium dioxide pigment whereby the silicon tetrachloride introduced in (b) does not influence crystal phase or carbon black undertone.

2 more elements

A durable rutile titanium dioxide pigment wherein at least 85% of the titanium dioxide particles are completely covered by a uniform layer formed from a mixture of amorphous aluminum oxide and amorphous silicon dioxide, the pigment produced by

(a) reacting titanium tetrachloride vapor and aluminum chloride and at least a stoichiometric amount of oxygen in a plug flow reactor to form a product stream containing more than 99% rutile titanium dioxide particles;
(b) determining the temperature in the reactor where not more than 3% of the titanium tetrachloride remains unreacted using
K
=
[
2
⁢
(
100
⁢
%
-
u
TiCl4
)
+
ϕ
×
100
⁢
%
]
2
u
TiCl4
⁡
(
β
+
u
TiCl4
)
and
T
<
20733
ln
⁢
⁢
K
+
6.391
-
273.15
⁢
where
uTiCl4=unreacted TiCl4 (%)
β=O2 (%) in excess of the stiochiometric amount
φ=feed Cl2 mole ratio (mol/mol TiCl4), and
T=temperature (C);
(c) introducing the silicon tetrachloride into the reactor where the temperature is equal to or less than the temperature calculated in step (b) to form durable rutile titanium dioxide pigment having a uniform layer of a mixture of amorphous aluminum oxide and silicon dioxide;
and
(d) withdrawing from the reactor the durable rutile titanium dioxide, whereby the silicon tetrachloride introduced in (c) does not influence either crystal phase or carbon black undertone.

50 more elements

Dependencies are inferred from the claim text.

Process for making durable rutile titanium dioxide pigment by vapor phase deposition of surface treatment

Life of this patent

Process for making durable rutile titanium dioxide pigment by vapor phase deposition of surface treatment

Life of this patent

Abstract

Claims30