Scour media for titanium dioxide production
Anatase titanium dioxide pigment calcined to a crush strength and density meeting the requirements for an acceptable scour medium is effectively utilized as a scour medium in the chloride process for producing rutile titanium dioxide. The calcining process converts a portion of the anatase pigment to rutile. This calcined anatase can, consequently, be utilized as a scour medium in the chloride process for producing rutile titanium dioxide. The calcined anatase is not a contaminant to the process for producing rutile titanium dioxide. Thus, relatively inexpensive anatase can be converted into a rutile scour medium that can be processed into pigment.
1 - 7 . (canceled)
8 . A method for producing rutile titanium dioxide, comprising the steps of:
calcining anatase titanium dioxide to a crush strength of less than about 30; and
introducing the calcined anatase into equipment for the production of rutile titanium dioxide.
9 . A method according to claim 8 , wherein the equipment is for the production of rutile titanium dioxide via the chloride process.
10 . A method according to claim 8 , wherein the anatase is calcined to a crush strength of greater than about 15.
11 . A method according to claim 8 , wherein the calcining step takes place at a temperature greater than about 1025° C.
12 . A method according to claim 8 , wherein the calcining step takes place at a temperature from about 1025° C. to about 1075° C.
13 . A method according to claim 8 , wherein the anatase is calcined to a density of from about 1.55 g/cm 3 to about 1.71 g/cm 3 .
14 . A method according to claim 8 , wherein the calcined anatase is introduced into an oxidation reactor.
15 . A method according to claim 8 , wherein the calcined anatase is introduced into a cooling conduit.
16 . A method for producing rutile titanium dioxide, comprising the steps of:
obtaining anatase titanium dioxide from an anatase production process;
calcining the anatase titanium dioxide to a crush strength of less than about 30; and
introducing the calcined anatase into equipment for the production of rutile titanium dioxide.
17 . A method according to claim 16 , wherein the anatase production process is a sulfate process for the production of anatase titanium dioxide.
18 . A method according to claim 16 , wherein the obtained anatase is obtained from calciner discharge from an anatase production process.
19 . A method according to claim 16 , wherein the anatase is calcined to a crush strength greater than about 15.
20 . A method for producing rutile titanium dioxide, comprising the steps of:
obtaining anatase titanium dioxide from a sulfate process for the production of anatase titanium dioxide;
calcining the anatase titanium dioxide to a crush strength of less than about 30 and greater than about 15; and
introducing the calcined anatase into equipment for the production of rutile titanium dioxide via the chloride process.
21 . A method according to claim 20 , wherein the calcining step takes place at a temperature greater than about 1025° C.
22 . A method according to claim 20 , wherein the calcining step takes place at a temperature from about 1025° C. to about 1075° C.
23 . A method according to claim 20 , wherein the anatase is calcined to a density of from about 1.55 g/cm 3 to about 1.71 g/cm 3 .
24 . A method according to claim 20 , wherein the calcined anatase is introduced into an oxidation reactor.
25 . A method according to claim 20 , wherein the calcined anatase is introduced into a cooling conduit.
26 . A method for producing rutile titanium dioxide, comprising the steps of:
obtaining anatase titanium dioxide from a sulfate process for the production of anatase titanium dioxide;
calcining the anatase titanium dioxide to a crush strength of less than about 30 and greater than about 15;
introducing the calcined anatase into equipment for the production of rutile titanium dioxide via the chloride process; and
producing titanium dioxide containing no more than about 2 percent by weight of anatase.
27 . A method according to claim 26 , wherein the producing step produces titanium dioxide containing no more than about 1 percent by weight of anatase.
28 . A method according to claim 26 , wherein the introduced calcined anatase comprises no more than about 5 percent of the produced titanium dioxide.
29 . A method according to claim 26 , wherein the introduced calcined anatase comprises no less than about 2.5 percent of the produced titanium dioxide.