JPH03183621A - Production of titanium concentrate - Google Patents

Abstract

PURPOSE:To obtain the high-grade titanium concentrate appropriate for fluidized chlorination by oxidizing a titanium contg. iron ore to a ferric oxide ore, reducing and then leaching the product with sulfuric acid. CONSTITUTION:A titanium-contg. iron ore is firstly oxidized at 900 deg.C or preferably at 950-1050 deg.C to obtain a ferric oxide ore having a pseudobrookite structure and in which 90-100% of iron is ferric. Since preoxidation is applied in this way prior to the reduction described below, the titanium-contg. iron ore, etc., are converted into the ore consisting essentially of a pseudobrookite structure. By this oxidation, 90-100% of iron in the ore is converted to ferric iron. The oxide iron is then reduced at 700-950 deg.C, and most of the iron is converted to the ferrous iron which is easy to leach in the succeeding leaching stage with sulfuric acid. The reduced ore is leached with sulfuric acid to remove the iron in the ore. The fine-grain powder is removed after leaching, and the remainder is cleaned, filtered and calcined at 800-1000 deg.C to obtain the desired titanium concentrate.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention uses titanium-containing iron ore or its analogs (hereinafter referred to as titanium-containing iron ore, etc.), and the iron content contained in the titanium-containing iron ore, etc. The present invention relates to a method for producing a titanium concentrate of high quality and suitable for chlorination by a fluidization method.

[Conventional technology]

Titanium tetrachloride, which is used as a raw material in the production of titanium dioxide pigments and metal titanium by the chlorine method, is usually obtained by chlorinating a titanium-containing raw material by a fluidization method. In this case, the titanium-containing raw material is high grade and has a slight crack).
It is important that the material does not contain carbon dioxide and is easily chlorinated by the fluidization method.

Such titanium-containing raw materials include high-grade titanium tHkm, which is obtained by removing iron from natural rutile or titanium-containing iron ores such as ilmenite and ilmenite/hematite ores.
things are being used. An industrial method for removing iron is a method in which titanium-containing iron ore is leached with sulfuric acid, in which the ore is reduced to a ferrous state in advance, and a sheet for promoting titanium salt hydrolysis is added during the leaching. and titanium (II
I) A method in which a salt is present (Japanese Patent Publication No. 49-18330, Japanese Patent Publication No. 49-37484).

[Problem to be solved by the invention]

In the conventional reduction-acid leaching method, highly metamorphosed titanium-containing iron ores, etc., whose titanium content is easily concentrated, have been used as raw materials, but recently, due to the decrease in these resources, less attention has been given to these materials as raw materials. There is a need to use titanium-containing iron ore with a low degree of metamorphism that has not been metamorphosed. but,
In the methods of the prior art, it is currently difficult to obtain the required high-grade titanium concentrate from ores with a low degree of metamorphism.

[Means to solve the problem]

The present inventors first obtained titanium-containing iron ore with a low degree of metamorphism.
Regarding the method of obtaining a titanium concentrate by oxidizing and reducing it, and then leaching it with sulfuric acid, we investigated various treatment conditions for each step. As a result, we found that the oxide ore has a pseudobrutskite structure and the iron content is 90 to 90%. By oxidizing the iron so that 100% of the iron is in the ferric state and then reducing it, the method of the present invention was completed by discovering that iron removal during leaching can be facilitated, especially when sulfuric acid is used as the mineral acid.

That is, the present invention oxidizes titanium-containing iron ore or its analogues to have a pseudopurufkite structure, and has an iron content of 9.
0 to 100% is ferric oxide ore, then 7
This is a method for producing a titanium concentrate, which comprises reducing the ore at 00 to 950°C and then leaching it with sulfuric acid to remove the iron content in the ore.

Furthermore, in the case of leaching with sulfuric acid, the method for producing a titanium concentrate includes using a titanium (DI) salt and/or a sheet for promoting titanium salt hydrolysis as necessary.

In the Kinoe IJIJ method, the titanium-containing iron ore used as the raw material ore includes titanium-containing iron ores such as ilmenite, metamorphosed products of ilmenite, such as ilmenite/hematite ores, or pre-treated ores of these ores. These include analogs with similar compositions and properties.

The effect of the present invention is remarkable when the ferrous iron content is 10
% or more of titanium-containing iron ore. The particle size of the ore used is 50 to 500 μm in diameter, and those larger than this can be used by pulverizing.

In the method of the present invention, first, titanium-containing iron ore etc. is
The oxidized ore is oxidized at a temperature of 0°C or higher, preferably 950 to 1050°C, has a pseudobrutzite structure, and has a ferric iron content of 90 to 100%.

In this way, by carrying out the oxidation treatment in advance of the reduction treatment described below, the titanium-containing iron ore or the like is changed into a state in which the pseudobrutzite structure is the main component. It is important that this oxidation treatment converts 90 to 100%, preferably 95 to 100%, of the iron content in the ore into ferric iron. If the oxide ore has a ferric content of less than 90% or a pseudobrutzite structure does not exist, iron removal by sulfuric acid leaching in the subsequent step cannot be carried out satisfactorily. As the oxidizing agent, an oxygen-containing gas such as air is usually used. A fluidized bed reactor, rotary kiln, or the like is used as a reaction device. The appropriate oxidation time is usually 10 to 120 minutes.

Next, this oxide ore is heated at 700 to 950°C, preferably at 80°C.
The iron is reduced at a temperature of 0 to 900°C, and most of the iron content is converted into ferrous iron, which is easily leached out in the sulfuric acid leaching step described later. Through this reduction treatment, the content of ferric iron in the reduced ore is reduced to 10% or less, preferably 5% or less relative to the iron content. If the reduction temperature is lower than 700°C, the ferric iron content (1) will be more than 10%, making it impossible to remove iron by leaching with sulfuric acid. On the other hand, if the reduction temperature is higher than 950°C, the elution of iron becomes poor and the titanium yield decreases, which is not preferable.

Reducing agents include gaseous reducing agents such as 11□, GO, mixed gases thereof, reducing gases obtained by reforming hydrocarbon gases such as natural gas, and solid reducing agents such as coke, coal, and charcoal. Agents are used. In particular, a reducing gas obtained by reforming natural gas or the like whose main component is methane is industrially desirable. A fluidized bed reactor, rotary kiln, etc. are used as the reduction reaction device. Reduction time is 11TIIQ-1
20 minutes is appropriate.

After reduction, if necessary, the reduced ore can be subjected to magnetic separation to remove impurity particles mainly composed of silica or alumina contained in the ore and residual reducing agent when a solid reducing agent is used.

Next, this reduced ore is leached with sulfuric acid. As a leaching agent,
In addition to sulfuric acid, mineral acids such as hydrochloric acid can be used, but sulfuric acid is best for achieving this purpose and for industrial use. Examples of the sulfuric acid include waste sulfuric acid discharged from the hydrolysis process of titanium dioxide production using the sulfuric acid method, and pickling acid discharged from the pickling process of iron manufacturing. The concentration of sulfuric acid is
Normally, 100-500g/1 as free 11□S04
is appropriate. The amount of sulfuric acid used is about 1.5 to 3 times the chemical equivalent required to dissolve impurities in the ore. The leaching temperature is usually from the boiling point to 150°C, and the treatment is carried out for 3 to 15 hours.

An autoclave or the like is used as a reaction device.

Furthermore, in this sulfuric acid leaching, titanium (I) was added to the leachate.
[I) The presence of a salt and/or titanium salt hydrolysis promoting sheet increases the elution rate of iron. Not only can the capacity be increased, but also the titanium yield can be increased. Methods for making titanium (I[I) salts present in the system include adding a titanium (III) sulfate solution, adding metal iron powder, etc. to the leachate, and adding titanium (TV) salts in the system to titanium (III). ) Methods include reducing it to salt. A sheet for promoting titanium salt hydrolysis is a seed crystal used to precipitate titanium by hydrolyzing a titanium salt solution in a general method for producing titanium dioxide pigments using a sulfuric acid method. An acidic solution of titanium salt such as sulfuric acid is neutralized, and the precipitated colloidal titanium compound is appropriately energized.

When titanium (III) salt and/or a sheet for promoting titanium salt hydrolysis is present, the amount of titanium (III) salt added is 1 to 1 in terms of Tie to the liquid level at the beginning of leaching.
15 g/l, preferably 2-10 g/l. The amount of the titanium salt hydrolysis promoting sheet added is approximately 0.05, assuming the titanium content in the sheet to the treated reduced ore as Ti0z.
-2%, usually 0.1-1%.

Next, after leaching with sulfuric acid, the shelf grain powder is removed, washed and filtered, and then, if necessary, dried and fired at 800 to 1000°C to obtain a high-grade titanium concentrate. Furthermore, if necessary,
It is also possible to magnetically separate the leachate before firing using a magnetic separator to separate the titanium concentrate as a non-magnetic material, and then to perform firing.

The titanium concentrate produced as described above has an extremely high TiO□ grade, and what's more? A: Since there is little paddy, it is suitable as a raw material for chlorination using the fluidization method.

In addition, the % display in this specification is weight % unless otherwise specified.

〔Example〕

Example 1 Table 1 (Unit: %) 1000 g of titanium-containing iron ore having the composition shown in Table 1 was charged into a rotary kiln, and a gas mixture of air and the same amount of nitrogen was passed through the kiln for 1000 minutes. Oxidized for 30 minutes at °C. In the obtained oxide ore, 99.2% of the iron content was in the state of ferric iron. When this oxide ore was analyzed by X-ray diffraction, an ilmenite structure was not observed, but a pseudobrutzite structure and a rutile structure were observed.

Subsequently, this oxide ore was heated with a reducing gas at 201/min (gas composition was TLZ: 50% by volume, Nz: 50% by volume).
Reduction was carried out at 850° C. for 45 minutes under a flow of water. Next, the mixture was cooled to 100° C. under nitrogen gas flow, and non-magnetic materials were removed using a small magnetic separator under conditions of 13,500 Gauss. The state of iron in this reduced ore is shown in Table 2 (T in Table 2
-Fe is the total iron content contained in the reduced ore). Further, as a result of analyzing this reduced ore by X-ray diffraction, no pseudobrutzite structure was observed.

Table 2 (Unit: 2%) Next, 400 g of this reduced t was placed in an iron autoclave equipped with a stirrer and lined with lead. Free 112SOa concentration 265g1ll)
1.21 was added and leached at 130°C for 8 hours.

Thereafter, fine particles were removed using a 200 mesh (74 μm) sieve, coarse particles were washed, filtered, dried, and then calcined at 900°C for 1 hour. A) was obtained.

Example 2 In Example 1, oxidation was performed at 1050°C for 20 minutes to obtain an oxide ore in which 99.6% of the iron content was ferric, and then this oxide ore was reduced at 750°C for 60 minutes. The titanium concentrate of the present invention (
Sample B) was obtained.

Example 3 In Example 2, titanium (In) sulfate was used in leaching with sulfuric acid at a converted amount of 6.0 g/I! A titanium concentrate (sample C) of the present invention was obtained by processing in the same manner as in Example 2 except for the addition.

Example 4 In Example 1, oxidation was carried out at 950° C. for 30 minutes to obtain an oxide ore in which 98.4% of the iron content was in the state of ferric iron, and then,
This oxide ore is heated with a reducing gas of 201/min (gas composition is lh
30% by volume, Co: 20% by volume, COz: 5% by volume, Nt: 45% by volume) at 850°C.
Reduction was carried out for 45 minutes (Fe3″″/T-
A titanium tl III material of the present invention (sample D) was prepared in the same manner as in Example 1 except that the Fe value was 4.8%.
I got it.

Example 5 In Example 4, a sheet for promoting hydrolysis obtained by neutralizing titanyl sulfate with 4.0 g/l of titanium (FIT) sulfate in terms of Ti0z during leaching with sulfuric acid was used to reduce the amount of titanium contained therein. A titanium concentrate (sample E) of the present invention was obtained in the same manner as in Example 4, except that 0.3% of TiO□-exchanged X was added.

Example G In Example 1, oxidation was carried out at 920°C for 60 minutes to obtain oxide ore in which 93.6% of the iron content was in the state of ferric iron, and this oxide ore was heated with reducing gas at 20C/min (gas composition was h; 30% by volume
, Co; 20% by volume, COx; 5% by volume, NA: 4
5% by volume) at 925°C for 30 minutes (the value of Fe''/T-Fe in the reduced ore was 4.0%).
Furthermore, during sulfuric acid leaching, titanium (III) sulfate was added to the titanium (III) sulfate in TiO□ equivalent amount '/, Og/l and titanyl sulfate was neutralized to obtain a sheet for promoting hydrolysis. A titanium concentrate (sample F) of the present invention was obtained in the same manner as in Example 1 except for adding 0.4% in terms of TiO2.

Comparative Example 1 In Example 1, oxidation was performed at 850°C for 90 minutes, and 92.0% of the iron content was in the ferric state, except that an oxide ore with no shaded brutzite structure was obtained. was treated in the same manner as in Example 1 to obtain a titanium concentrate (sample G).

Comparative Example 2 In Example 1, oxidation was carried out at 800°C for 120 minutes to obtain an oxide ore in which 88.0% of the iron content was in the ferric state and no shaded brutzite structure was observed, and further sulfuric acid leaching. Sometimes titanium (nI) sulfate is 7% in terms of TiO2.
．． Titanium was treated in the same manner as in Example 1, except that 0.4% of the titanium contained in the sheet for promoting hydrolysis obtained by neutralizing titanyl sulfuric acid was added in an amount equivalent to TiO□. A concentrate (sample H) was obtained.

Comparative Example 3 Titanium was treated in the same manner as in Example 1 except that the reduction was performed at 975° C. for 30 minutes and the Fe''/T-FeO value in the reduced ore was 4.4%. aI product (sample sample was obtained).

Comparative Example 4 In Example 1, reduction was performed at 650°C for 90 minutes (
The value of Fe''/T-Fe in the reduced ore was 17.6%).
The force obtained by neutralizing titanyl sulfate to 7.0 g/e with O A titanium concentrate (Sample J) was obtained by processing in the same manner as in 1.

Table 3 shows the Tioz grade, Tiet yield, and iron removal rate of the titanium concentrate obtained as described above. The Tioz grade in Table 3 is the percentage of Ti1t content in the titanium concentrate, and the Ti0z yield is the percentage of Ti1t content in the reduced ore used for leaching.
It is the percentage of the amount of TiO□ in the titanium concentrate with respect to 02l, and the iron removal rate is the percentage of the leached iron content to the iron content in the reduced ore used for leaching.

Table 3 [Effects of the Invention] The present invention can produce high-grade titanium t! from titanium-containing iron ore with a low degree of metamorphosis without significantly changing conventional equipment technology. i
This is a method to obtain a condensate. The titanium concentrate obtained by this method is suitable as a raw material for chlorination by industrial fluidization methods.

Claims (1)

[Scope of Claims] 1. Titanium-containing iron ore or its analogues are oxidized to form an oxide ore having a pseudobrookite structure with 90 to 100% of the iron content being ferric, and then 700 to 950% of the iron content is ferric. A method for producing a titanium concentrate, which comprises reducing the titanium concentrate at °C and then leaching it with sulfuric acid to remove the iron content in the ore. 2. The method for producing a titanium concentrate according to claim 1, which comprises leaching with sulfuric acid in the presence of a titanium (III) salt and/or a titanium salt hydrolysis promoting sheet.