US5011666A — Method for purifying TiO2 ore

Claim 1

Independent Claim 168 words

Process for purifying TiO 2 ore containing impurities of iron, alkali metal, alkaline earth metal, rare earth metal, aluminum, phosphorus, thorium, uranium, chromium, manganese, silicon, vanadium, and yttrium, said process consisting essentially of subjecting the ore to two or more leaching treatments, said leaching treatment: (a) alternating between use of an aqueous solution of a mineral acid and an aqueous solution of an alkali metal compound selected from the group consisting essentially of alkali metal carbonates, hydroxides or mixtures thereof, and wherein the treatment with a mineral acid occurs first, and (b) being conducted at a temperature, pressure, and time, and with an amount and concentration of an aqueous solution of a mineral acid and an aqueous solution of an alkali metal compound, which are sufficient to solubilize substantially the iron, alkali metal, alkaline earth metal, rare earth metal, aluminum, phosphorus, thorium, uranium, chromium, manganese, silicon, vanadium, and yttrium impurities present to form a leachate, and wherein the leachate formed is removed prior to the next leaching treatment.

Claim 2

Dependent Claim 168 words

Process for purifying TiO 2 ore containing impurities of iron, alkali metal, alkaline earth metal, rare earth metal, aluminum, phosphorus, thorium, uranium, chromium, manganese, silicon, vanadium, and yttrium, said process consisting essentially of subjecting the ore to two or more leaching treatments, said leaching treatment: (a) alternating between use of an aqueous solution of a mineral acid and an aqueous solution of an alkali metal compound selected from the group consisting essentially of alkali metal carbonates, hydroxides or mixtures thereof, and wherein the treatment with a mineral acid occurs first, and (b) being conducted at a temperature, pressure, and time, and with an amount and concentration of an aqueous solution of a mineral acid and an aqueous solution of an alkali metal compound, which are sufficient to solubilize substantially the iron, alkali metal, alkaline earth metal, rare earth metal, aluminum, phosphorus, thorium, uranium, chromium, manganese, silicon, vanadium, and yttrium impurities present to form a leachate, and wherein the leachate formed is removed prior to the next leaching treatment.

Claim 3

Dependent Claim 48 words

The process of claim 1 wherein the alkali metal compound used for the leaching treatment consists essentially of sodium hydroxide, sodium carbonate or mixtures thereof, and the mineral acid used for the leaching treatment consists essentially of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid or mixtures thereof.

Claim 4

Dependent Claim 74 words

The process of claim 2 wherein the alkali metal compound used for the leaching treatment is present in an amount of about 2-50% by weight, based on the total weight of the solution; the mineral acid used for the leaching treatment is present in an amount of about 1-40% by weight, based on the total weight of the solution; and the TiO 2 ore has a particle size of about -20 to +400 mesh.

Claim 5

Dependent Claim 60 words

The process of claim 3 wherein the alkali metal compound used for the leaching treatment is present in an amount of about 10-40% by weight, based on the total weight of the solution, and the mineral acid used for the leaching treatment is present in an amount of about 3-35% by weight, based on the total weight of the solution.

Claim 6

Dependent Claim 60 words

The process of claim 3 wherein the alkali metal compound used for the leaching treatment is present in an amount of about 20-30% by weight, based on the total weight of the solution, and the mineral acid used for the leaching treatment is present in an amount of about 5-25% by weight, based on the total weight of the solution.

Claim 7

Dependent Claim 41 words

The process of claim 3 wherein the alkali metal compound is sodium hydroxide which is present in an amount of about 10-40% by weight, and the acid is hydrochloric acid which is present in an amount of about 3-35% by weight.

Claim 8

Dependent Claim 106 words

The process of claim 1 wherein prior to the leaching treatments the ore is subjected to mineral dressing; the leaching treatment with an aqueous solution of a mineral acid takes place at a temperature of about ambient to about 150° C., a pressure of about 1-10 atmospheres, and for a time of about 10 minutes to about 8 hours; the leaching treatment with a solution of an alkali metal compound takes place at a temperature of about 60-240° C., a pressure of about 1-30 atmospheres, and a time of about 10 minutes to about 8 hours; and the removal of the leachate includes washing with water.

Claim 9

Dependent Claim 107 words

The process of claim 2 wherein prior to the leaching treatments the ore is subjected to mineral dressing; the leaching treatment with an aqueous solution of a mineral acid takes place at a temperature of about ambient to about 150° C., a pressure of about 1-10 atmospheres, and for a time of about 10 minutes to about 8 hours; the leaching treatment with an aqueous solution of an alkali metal compound takes place at a temperature of about 60°-240° C., a pressure of about 1-30 atmospheres, and a time of about 10 minutes to about 8 hours; and the removal of the leachate includes washing with water.

Claim 10

Dependent Claim 107 words

The process of claim 3 wherein prior to the leaching treatments the ore is subjected to mineral dressing; the leaching treatment with an aqueous solution of a mineral acid takes place at a temperature of about ambient to about 150° C., a pressure of about 1-10 atmospheres, and for a time of about 10 minutes to about 8 hours; the leaching treatment with an aqueous solution of an alkali metal compound takes place at a temperature of about 60-240° C., a pressure of about 1-30 atmospheres, and a time of about 10 minutes to about 8 hours; and the removal of the leachate includes washing with water.

Claim 11

Dependent Claim 107 words

The process of claim 4 wherein prior to the leaching treatments the ore is subjected to mineral dressing; the leaching treatment with an aqueous solution of a mineral acid takes place at a temperature of about ambient to about 150° C., a pressure of about 1-10 atmospheres, and for a time of about 10 minutes to about 8 hours; the leaching treatment with an aqueous solution of an alkali metal compound takes place at a temperature of about 60°-240° C., a pressure of about 1-30 atmospheres, and a time of about 10 minutes to about 8 hours; and the removal of the leachate includes washing with water.

Claim 12

Dependent Claim 108 words

The process of claim 5 wherein prior to the leaching treatments the ore is subjected to mineral dressing; the leaching treatment with an aqueous solution of a mineral acid takes place at a temperature of about ambient to about 150° C., and a pressure of about 1-10 atmospheres, and for a time of about 10 minutes to about 8 hours; the leaching treatment with an aqueous solution of an alkali metal compound takes place at a temperature of about 60°-240° C., a pressure of about 1-30 atmospheres, and a time of about 10 minutes to about 8 hours; and the removal of the leachate includes washing with water.

Claim 13

Dependent Claim 111 words

The process of claim 6 wherein the ore is anatase; prior to the leaching treatments the ore is subjected to mineral dressing; the leaching treatment with an aqueous solution of a mineral acid takes place at a temperature of about ambient to about 150° C., a pressure of about 1-10 atmospheres, and for a time of about 10 minutes to about 8 hours; the leaching treatment with an aqueous solution of an alkali metal compound takes place at a temperature of about 60-240° C., a pressure of about 1-30 atmospheres, and a time of about 10 minutes to about 8 hours; and the removal of the leachate includes washing with water.

Claim 14

Dependent Claim 34 words

The process of claim 7 wherein the leaching treatment with an aqueous solution of an alkali metal compound takes place at a temperature of about 30°-210° C. and a pressure of about 3-18 atmospheres.

Claim 15

Dependent Claim 34 words

The process of claim 8 wherein the leaching treatment with an aqueous solution of an alkali metal compound takes place at a temperature of about 130°-210° C. and a pressure of about 3-18 atmospheres.

Claim 16

Dependent Claim 34 words

The process of claim 9 wherein the leaching treatment with an aqueous solution of an alkali metal compound takes place at a temperature of about 130°-210° C. and a pressure of about 3-18 atmospheres.

Claim 17

Dependent Claim 34 words

The process of claim 10 wherein the leaching treatment with an aqueous solution of an alkali metal compound takes place at a temperature of about 130°-210° C. and a pressure of about 3-18 atmospheres.

Claim 18

Dependent Claim 34 words

The process of claim 11 wherein the leaching treatment with an aqueous solution of an alkali metal compound takes place at a temperature of about 130°-210° C. and a pressure of about 3-18 atmospheres.

Claim 19

Dependent Claim 34 words

The process of claim 12 wherein the leaching treatment with an aqueous solution of an alkali metal compound takes place at a temperature of about 130°-210° C. and a pressure of about 3-18 atmospheres.

Claim 20

Dependent Claim 32 words

The process of any of claims 1-18 wherein the first leaching treatment uses an aqueous solution of a mineral acid, and the total number of leaching treatments does not exceed about 10.

Claim 21

Dependent Claim 32 words

The process of any of claims 1-18 wherein the first leaching treatment uses an aqueous solution of a mineral acid, and the total number of leaching treatments does not exceed about 5.

Claim 22

Dependent Claim 31 words

The process of any claim 1-18 wherein the first leaching treatment uses an aqueous solution of a mineral acid, and the total number of leaching treatment does not exceed about 3.

Claim 23

Dependent Claim 31 words

The process of any of claim 1-18 wherein the first leaching treatment uses an aqueous solution of a mineral acid, and the total number of leaching treatment does not exceed 2.

Claim 24

Dependent Claim 39 words

The process of any of claim 1-18 wherein either (a) there is no roasting prior to leaching or (b) if roasting is done prior to leaching, it is carried out at a temperature of less than about 700° C.

Claim 25

Dependent Claim 49 words

The process of any of claims 1-18 wherein either (a) there is no roasting prior to leaching or (b) if roasting is done prior to leaching, it is carried out at a temperature of less than about 700° C., and the total number of leaching steps is about 2-10.

Claim 26

Dependent Claim 51 words

The process of any of claims 1-18 wherein either (a) there is no roasting prior to leaching or (b) if roasting is done prior to leaching, it is carried out at a temperature of less than about 700° C., and the total number of leaching steps does not exceed about 3.

Claim 27

Dependent Claim 57 words

The process of any of claims 1-18 wherein either (a) there is no roasting prior to leaching or (b) if roasting is done prior to leaching, it is carried out at a temperature of less than about 700° C., the total number of leaching steps does not exceed about 3, and the TiO 2 ore is anatase.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1994-04-29	1994-10-29	1995-04-30	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1998-04-29	1998-10-29	1999-04-30	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2002-04-29	2002-10-29	2003-04-30	$7700.00	Window Closed / Lapsed

Method for purifying TiO2 ore

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