CN1136534A

CN1136534A - Production of rutile type TiO2 by impurity removing oxidation method

Info

Publication number: CN1136534A
Application number: CN 96104182
Authority: CN
Inventors: 潘玮; 潘立生
Original assignee: CHENGGONG XINGHE INDUSTRY GENERAL CORP
Current assignee: CHENGGONG XINGHE INDUSTRY GENERAL CORP
Priority date: 1996-04-05
Filing date: 1996-04-05
Publication date: 1996-11-27

Abstract

The invented method consists of the following process: mixing material to make ball-pellet sintering-reductive smelting-water quenching titanium dross,-acid hydrolysis-oxidation calcination-acid pickling-oven drying. The process provided by said invention features good comprehensive utilization, besides obtaing pig iron and rutile type TiO2, it can recover the nonferrous metal elements, the used chemicals can all be reformed into chemical raw material, so no waste water is drained. Said process features also less investment, simple equipment maintenace and low protective cost.

Description

Impurity-removing oxidation process for producing rutile type titanium dioxide

The invention relates to a preparation method of titanium dioxide, in particular to a method for producing rutile type titanium dioxide by impurity removal oxidation.

At present, two methods for producing titanium dioxide at home and abroad are sulfuric acid method and chlorination method, wherein the former method generates a large amount of ferrous sulfate in the production process, a large amount of 10-20% dilute sulfuric acid is discharged, and besides serious pollution to the environment, a large amount of sulfuric acid resources are lost.

The invention aims to provide a method for producing rutile titanium dioxide, which does not discharge harmful substances in the production process and can recover valuable substances to convert the valuable substances into chemical raw materials.

The invention is as follows: the method takes titanic iron ore (FeTiO3) as a raw material, utilizes the characteristic that the chemical stability difference between titanium oxide and iron oxide is large and the characteristic that various impurities can be converted into soluble salt according to the components in the titanic iron ore and the chemical characteristics of various elements in the titanic iron ore, separates the titanium and the iron, and recovers nonferrous metals Gr, V, Mn, AC and the like, and particularly adopts alkali carbonate as a cosolvent for slagging, and the reaction formula is as follows:

about 1400 deg.C

About 160.0 deg.C

Simultaneously, flux sodium carbonate reacts with impurities in the ore:

sodium carbonate reacts with TiO2 by-product:

the separated iron ingot is cast to obtain pig iron product, the iron-removed high titanium slag is collected and leached by water, and the alkali metal titanate can be instantly used when meeting waterHydrolyzing to generate metatitanic acid and orthotitanic acid, heating and boiling to destroy titanic acid colloid, so that titanic acid generates stable metatitanic acid, metatitanic acid is insoluble in alkali liquor to generate precipitate, calcium titanate and magnesium titanate are precipitated, other impurities NaAlO2, NaSiO3, Na2MnO4 and Na2CrO4 are remained in the solution, filtering, washing and separating to remove soluble components, and collecting precipitates of metatitanic acid, calcium titanate, magnesium titanate and the like.

A mixture of metatitanic acid, calcium titanate and magnesium titanate is treated with nitric acid to convert all of them to metatitanic acid. Metatitanic acid does not react with nitric acid, calcium titanate and magnesium titanate are decomposed by nitric acid to generate calcium nitrate and magnesium nitrate which are dissolved into solution, and metatitanic acid is precipitated and separated out:

filtering and washing to remove calcium nitrate and magnesium nitrate, collecting metatitanic acid, drying and dehydrating to obtain titanium dioxide (TiO 2).

The specific process steps of the invention are as follows:

a. mixing materials and preparing balls, adding carbon powder, soda ash and a binder into ilmenite, fully and uniformly mixing to prepare balls, wherein the ball diameter is 30-70cm, and the mixing ratio is as follows: ilmenite, carbon powder, soda ash and binder in the weight ratio of 1 to 0.2-0.25 to 0.15-0.2 to 0.2;

b. and (3) pellet roasting, namely heating and roasting the prepared pellets in a roasting furnace at 1050-1150 ℃ for 1.00-1.50 hours.

c. And (3) reduction smelting, namely smelting the roasted pellets in an electric furnace, and casting pig iron reduced at the smelting temperature of 1250-1400 ℃ into pig iron products.

d. Water extraction of titanium slag, water spraying of the iron-removed high titanium slag to form water slag, filtering, and collecting filtrate to recover valuable substances;

e. carrying out acidolysis on the high titanium slag, adding nitric acid into filter residues for acidolysis, wherein the adding amount of the nitric acid is that 100 kg of nitric acid with the concentration of 60 percent (by weight) is added into each ton of the high titanium slag, the reaction time is 2-4 hours, filtering is carried out after acidolysis, and the filtrate is recovered and valuable substances are extracted;

f. performing transformation oxidation calcination, namely calcining the metatitanic acid subjected to acidolysis in a fluidized bed at the temperature of 800-1000 ℃ to fully oxidize TiO 2;

g. acid washing and filtering, adding nitric acid with the concentration of 40% into the calcined material for washing treatment, wherein the adding amount ratio of the nitric acid to the mixture is 1: 0.07-0.15, collecting a precipitate TiO2 after treatment, and neutralizing the washed solution with lime milk to obtain the fertilizer calcium nitrate.

h. Drying and pulverizing, drying TiO2at 200-250 deg.C, and pulverizing to obtain rutile type TiO 2.

Compared with the prior art, the invention has the following advantages and effects:

1. the method has good comprehensive utilization, can recover nonferrous metals Cr, V, Mn, Al and the like besides obtaining titanium dioxide and pig iron products by treating the ilmenite, and simultaneously can convert various chemicals used in production into chemical raw materials such as calcium hydrophosphate, calcium magnesium nitrate, sodium nitrate and the like, so that pollution to the environment is avoided, and the production cost is reduced.

2. The method provided by the invention has the advantages of small investment, simple and convenient production operation, simple equipment maintenance and easy obtainment of used raw materials.

The present invention will be described in further detail with reference to examples.

1. Taking 50 tons of ilmenite, wherein the chemical components are as follows: TiO 248-52%, FeO 31%, Fe2O 331%, and the balance of SiO2, Al2O3, Cr2O3, MnO2, V2O5, MgO, CaO and other impurities.

Adding 20 tons of carbon powder, 15 tons of soda ash and 20 tons of binder, and uniformly mixing to prepare pellets of 30-70 cm.

2. The pellets are sent into a heating furnace to be roasted for 1 hour at the temperature of 1050-;

3. and (3) putting 50 tons of roasted pellets into an electric furnace for smelting, controlling the temperature to be 1250-1400 ℃, putting molten iron and casting ingots after separating slag and iron, and then discharging high-titanium slag.

4. Spraying water to treat the high titanium slag to form water slag, filtering to remove iron-containing slag toobtain high titanium slag, and recovering the filtrate to extract valuable substances.

5. And (3) putting 10 tons of the high titanium slag into a stirring container, adding 1 ton of nitric acid with the concentration of 60%, stirring for 2 hours to obtain a precipitate, collecting filtrate, and extracting valuable substances.

6. And (3) putting the precipitate into a fluidized bed at the temperature of 1000 ℃ for oxidation and calcination to obtain the rutile titanium dioxide.

7. 0.7 ton of nitric acid solution with the concentration of 40 percent is added into the titanium dioxide, precipitate is obtained after full stirring, and valuable substances are recovered after filtrate is neutralized by lime milk.

8. Drying the precipitate at 200 deg.C, and pulverizing to obtain snow-white rutile type titanium dioxide.

Claims

1. A process method for producing rutile titanium dioxide by impurity removal oxidation comprises the process steps of mixing materials, pelletizing, sintering, reduction smelting, calcining, drying and the like, and is characterized in that:

a. the process adopts alkali carbonate as cosolvent for slagging, and the addition amount of the alkali carbonate is that the ratio of ore to cosolvent is 1: 0.15-0.2;

b. spraying the titanium slag obtained by reduction smelting with water to form water slag, and filtering to obtain high-titanium slag;

c. adding nitric acid with the concentration of 40-60 percent (weight) into the high titanium slag for acidolysis, wherein the adding amount is that 100-150kg of nitric acid is added into each ton of the high titanium slag.

2. The process of claim 1 wherein nitric acid is added during the acid washing in an amount such that the mixture nitric acid is 1: 0.07-0.15.

3. The process of claim 1, wherein the co-solvent is an alkali metal hydroxide.