JP6842245B2 - How to purify Ti - Google Patents

Description

The present invention relates to a method for purifying Ti. More specifically, the present invention relates to a method for separating Si from a mixture containing Ti.

Titanium is purified from titanium ore by the Kroll process. In this Kroll process, titanium ore and coke are charged into the fluidized bed reactor, and chlorine gas is blown in from the bottom of the fluidized bed reactor. As a result, gaseous titanium tetrachloride is produced, which is recovered and reduced with magnesium or the like, and finally titanium sponge is produced.

Various wastes are generated in the process of refining titanium. However, some of these wastes contain useful substances. Patent Document 1 discloses a method for recovering a useful metal from titanium ore. Specifically, a method of chlorinating titanium ore and leaching the obtained crude chlorinator residue with HCl is disclosed.

Further, Patent Document 2 discloses a method for recovering unreacted titanium ore and coke from the chloride residue. Specifically, after washing with water, the chloride residue is separated into solids and waste liquids, and since the solids contain unreacted titanium ore and coke, they are returned to the fluidized bed reactor for reuse. Is disclosed.

Japanese Patent Application Laid-Open No. 3-115534 JP-A-2014-181153

In the above-mentioned Kroll process, as shown in FIG. 10, impurity metal chloride is produced. These are usually discarded, which is costly. On the other hand, impurity metal chlorides contain useful substances. For example, Ti, Si, and carbon are mixed in the impurity metal chloride. Therefore, it would be industrially beneficial if titanium could be recovered without discarding such a mixture as is. In addition, it would be more useful if the contamination of other substances could be suppressed during recovery. In particular, Ti and Si mixed in the above-mentioned impurity metal chloride are present in the form of _{TiO 2} and SiO _{2, respectively, and are difficult to separate.} Therefore, an object of the present invention is to provide a method for recovering titanium by improving the titanium grade while suppressing the mixing of a specific substance.

As a result of diligent investigation by the present inventor, _{it was found that TiO 2} and SiO ₂ have different specific gravities, and it was found that the quality of Ti can be improved by using a separation method using this.

Based on these findings, the present invention is specified as follows.
(Invention 1)
A method of recovering Ti from chloride residue in titanium smelting.
The process of performing flotation treatment on the chloride residue to obtain tailing, flotation, and post-flotation liquid.
The method comprising the step of performing specific gravity sorting on the taillings and thereby removing Si.
(Invention 2)
The method according to invention 1, wherein the specific gravity sorting is a wet specific gravity sorting using a table sorter.
(Invention 3)
The method according to the invention 1 or 2, further comprising a step of recovering a fraction _{having a TiO 2} / (TiO ₂ + SiO _{2) of 0.9 or more after the specific gravity sorting.}
(Invention 4)
The method according to any one of the inventions 1 to 3.
The method includes a step of classifying the chloride residue into coarse particles and fine particles before performing the flotation treatment.
The step of performing the flotation treatment is carried out on the coarse grains, the method.
(Invention 5)
The method according to any one of the inventions 1 to 3.
The method comprises a step of classifying the tailling into coarse and fine grains between the flotation treatment and the specific gravity sorting.
The step of classifying is carried out on the tailing obtained by the flotation treatment, and the step is carried out.
The method, wherein the specific gravity sorting is performed on the coarse grains.

In the present invention, in one aspect, a step of performing flotation treatment is carried out. As a result, titanium can be distributed to the taillings after reducing the amount of carbon and the like mixed in. Further, in the present invention, in one aspect, a step of performing specific gravity sorting is carried out. This makes it possible to reduce the amount of Si and the like mixed in.

It is a flow chart for recovering Ti which concerns on one Embodiment of this invention. It is a flow chart for recovering Ti which concerns on one Embodiment of this invention. It is a flow chart for recovering Ti which concerns on one Embodiment of this invention. It is a figure which shows the specific gravity sorting which concerns on one Embodiment of this invention. In one embodiment of the present invention, the distribution rate when flotation is performed is shown. In one embodiment of the present invention, the result of specific gravity sorting when the inclination angle is 5 ° is shown. In one embodiment of the present invention, the result of specific gravity sorting when the inclination angle is 3.5 ° is shown. In one embodiment of the present invention, the result of specific gravity sorting when the inclination angle is 2 ° is shown. In one embodiment of the present invention, the classification result of the chloride residue is shown. In one embodiment of the present invention, the classification results of Ti and Si in the chloride residue are shown. It is a figure about the Kroll process (conventional technique).

1. 1. Chloride residue
1-1. Purification of Titanium Conventionally, titanium is generally purified from titanium ore by the Kroll process. FIG. 10 shows a part of the flow. Titanium ore and coke are put into a fluidized bed reactor. Then, chlorine gas is blown in from the lower part of the fluidized bed reactor. Titanium ore reacts with chlorine gas to produce titanium tetrachloride. Titanium tetrachloride is in a gaseous state at the temperature inside the reactor. This gaseous titanium tetrachloride is sent to the next cooling system for cooling. The cooled titanium tetrachloride becomes liquid and is recovered.

1-2. When titanium tetrachloride chloride residue gas state is sent to the next cooling system aboard the airflow pulverulent impurities it is sent to the cooling system together. The impurities include substances other than titanium (iron, scandium, vanadium, silicon, etc., some chlorides), unreacted ore, unreacted coke, and the like. These impurities are recovered in solid form in the cooling system. In the present specification, this recovered product is referred to as a chloride residue. The chloride residue may be slurryed or in the form of a group of dry particles. Typically, a slurry can be used to recover the valuable metal.

1-3. Chloride residue grade The chloride residue obtained in the above steps may contain various useful substances. For example, about 260 kg of Ti may be present in 1 ton of chloride residue. Therefore, if Ti can be recovered without discarding such chloride residue as it is, the disposal cost can be suppressed, and at the same time, the profit can be improved by using the recovered product.

1-4. Pretreatment of Chloride Residue The above-mentioned chloride residue is in a high temperature state immediately after being recovered during titanium smelting, and needs to be cooled before the treatment for recovering titanium from the high temperature state. The cooling method is not particularly limited, and cooling may be performed by means such as air cooling or water cooling.

Further, it is preferable to wash the chloride residue with water before performing flotation or classification described later. This is because water-soluble impurities such as _{FeCl 2 can be removed by washing with water.} Further, in the case of washing with water, the above-mentioned cooling treatment can be performed at the same time.

2. Froth flotation (floth flotation)
By performing flotation (flotation) on the chloride residue, a desired substance can be recovered and an undesired substance can be eliminated. More specifically, by performing flotation, the substance in the chloride residue can be sorted into taillings, flotation, and post-flotation liquid. For example, Ti is mainly distributed to Tailings, and carbon and the like are mainly distributed to floating ores. Then, the desired substance can be recovered from each fraction. Undesirable substances are distributed to other fractions, which can increase the recovery rate. Further, as will be described later, the chloride residue may be classified before and after the flotation.

2-1. As a condition of flotation for the flotation conditions the recovery and elimination, it is possible to adopt the following conditions.
Pulp concentration 200-600 (dry-g / L)
Frothation time 5 to 30 minutes Frothation pH 2 or more (preferably 5 or less, more preferably 4 or less)
Collection agent 100-300 g / t (preferably 200-300 g / t)
Foaming agent 50-200 g / t (preferably 100-150 g / t)

The catching agent acts to increase the hydrophobicity of the surface of the target mineral by selectively adsorbing it on the surface of the mineral. Specific examples of the substance include, but are not limited to, kerosene and the like. The amount of the catching agent is 100 to 300 g / t (preferably 200 to 300 g / t). If it is less than 100 g / t, it is difficult to obtain floating ore, which is not desirable. If it is more than 300 g / t, the effect reaches a plateau, so there is no point in adding more.

A foaming agent is a substance that dissolves in a solvent and stabilizes the foam in a solution. Specific examples of the substance include, but are not limited to, methylisobutylcarbinol (MIBC), pine oil and the like. The amount of foaming agent is 50 to 200 g / t (preferably 100 to 150 g / t). If it is less than 50 g / t, it is difficult to obtain floating ore, which is not desirable, and if it is more than 200 g / t, the effect reaches a plateau, so there is no point in adding more. Furthermore, when an excessive amount of foaming agent is added, the particles that should be originally distributed to the Tailings side are distributed to the Tailings side, which lowers the quality of carbon recovered as the Tailings and reduces the amount of Ti contained in the Tailings. There are disadvantages such as.

For Tailings, specific gravity sorting, which will be described later, can be performed. If necessary, the tailling may be leached with a specific element (eg, Sc, V, Al, Cr, etc.) in advance with HCl or the like before the specific gravity sorting is performed. Then, the leaching residue may be subjected to specific gravity sorting.

3. 3. Specific Gravity Sorting After performing the flotation described above, the taillings can be recovered for further sorting. Alternatively, after performing the classification described later, further sorting can be performed on the coarse grains.

3-1. Specific Gravity of Titanium Oxide (TiO ₂ etc.) and SiO _{2 In} addition to titanium, Si etc. are mixed in the above-mentioned tailing or coarse grains. Titanium exists in the form of titanium oxide, and Si exists in the form of _{SiO 2.} The specific gravities of titanium oxide and SiO _{2 are as follows.}

Therefore, the specific gravity of titanium oxide is larger than that of titanium oxide _{and SiO 2.} Therefore, by performing a sorting method using the difference in specific gravity, it is possible to suppress the mixing of _{SiO 2.}

3-2. Types of Specific Gravity Sorting The specific gravity sorting used in the present invention is not particularly limited and may be wet or dry. However, if the sorting target is the taillings obtained through flotation, the dry type requires time and effort to dry the taillings in advance. For this reason, it is preferably wet.

In addition, there are various classifications for specific gravity sorting other than wet type and dry type. Heavy-liquid sorting, hydraulic sorting, air sorting, and the like can be mentioned based on the material that is the medium for sorting. In the present invention, any selection may be used. As a more specific example, in the present invention, a table sorter, a cone sorter, a spiral sorter, a centrifugal specific gravity beneficifier, and the like can be used. In the following, as a typical method, wet specific gravity sorting using a table sorter will be described.

3-3. In the table-type table sorter, as shown in FIG. 3, the table is tilted at a predetermined angle (in FIG. 3, it is tilted so as to descend from top to bottom), and from the upper right side. The object can be thrown into the table. At the same time, the table can be vibrated in a direction perpendicular to the tilt direction. In addition, collection spots (1 to 7 in FIG. 3) can be provided on the lower edge side of the table. In some cases, water may be sprinkled from the porch above the table.

Each component is distributed in different proportions to each of the spots 1 to 7 according to the specific gravity. How it is distributed can be adjusted by considering the angle of the table, the amplitude of the table, the number of rotations of the table, the amount of water, and the like.

However, if it is set to extreme conditions, it will be difficult for titanium and Si to separate (and the quality of titanium will not improve), or the recovery rate of titanium will decrease, which is typical. Therefore, it is preferable to determine the conditions within the following range.
Tilt angle> 2 ° to 5 ° or less (preferably more than 2.5 ° to 3.5 ° or less),
Amplitude 5 mm to 10 mm (preferably 6 mm to 8 mm)
Rotation speed 200 rpm to 600 rpm (preferably 300 rpm to 500 rpm)
Shower water volume 5L / min-10L / min (preferably 6L / min-8L / min)

Further, the collection spots are also provided at seven places in FIG. 3, but the number, size, and position of the spots are not particularly limited. In reality, particles with a higher specific gravity tend to move to the lower left side as referred to in FIG. 3, and it is preferable to set the optimum number and position of recovery spots in consideration of this.

3-4. Content of Ti and Si By the above specific gravity selection, the grade of Ti can be increased and the content of Si can be decreased. For example, the grade [%] of Ti and Si as elements is analyzed to determine the content [g] of each element in the residue, and it is assumed that they _{are all in the form of TiO 2} and SiO _{2 , respectively, and TiO 2} and SiO _{2 are used.} The calculated value of the content [g] of TiO ₂ / (TiO ₂ + SiO ₂ ) is preferably 0.90 or more, more preferably 0.92 or more, and most preferably 0.95 or more. be able to. Such a fraction with increased Ti quality can be obtained at a specific collection spot.

3-5. Utilization of recovered Ti Since the fraction recovered in the above-mentioned step has a high grade of titanium, it can be put into the flow reactor in the Kroll process again by granulating and sizing. In particular, _{if the recovered product has TiO 2} / (TiO ₂ + SiO ₂ ) of 0.90 or more, it is considered that there is little concern that the purity of _{TiCl 4 obtained in the flow reactor will be lowered.}

4. Classification method Further, in a further embodiment, classification may be performed before and after the flotation process described above (FIG. 2A). More specifically, classification may be performed, the chloride residue may be divided into coarse grains and fine grains, and flotation treatment may be performed on the coarse grain side. Alternatively, after the flotation treatment, the taillings may be classified into coarse grains and fine grains (FIG. 2B). The reason for this is that particles containing a specific element are often unevenly distributed on the fine particle side (eg, Si, etc.). Therefore, by classifying, particles containing a specific element in advance can be excluded. As a result, it is possible to suppress the mixing of impurities when recovering Ti.

When the chloride residue is classified, it is preferable to wash the chloride residue with water before the classification. This is because, as described above, water-soluble impurities such as _{FeCl 2 can be removed by washing with water.} Further, in the case of washing with water, the above-mentioned cooling treatment can be performed at the same time.

The chloride residue or the tailling after flotation can be classified into coarse grains and fine grains. The classification method is not particularly limited and may be dry or wet. More preferred is wet. This is because when the chloride residue is washed with water, it does not require the trouble of drying. Moreover, as a method of classification, a sieve having a specific size of a mesh may be used. As the wet classification, a hydraulic classifier, a horizontal water flow classifier, and a centrifugal settler classifier may be used. As the dry classification, an air separator or an air classification machine may be used.

The classification reference value is not particularly limited, and may be adopted as the upper limit value in consideration of the range of the particle group containing a large amount of Si. For example, the upper limit of the reference value may be 53 μm or less, 38 μm or less, or 25 μm or less. The lower limit of the reference value may be 10 μm or more, 15 μm or more, or 20 μm or more. As a result, on the coarse grain side, about 38% (when the reference value is set to about 53 μm), about 33% (when the reference value is set to about 38 μm), or about 38% of the Si present in the chloride residue. 30% (when the reference value is set to about 25 μm) can be removed.

When a sieve is used as the classification means, the size of the mesh can be appropriately determined based on the reference value for the classification. For example, when classifying with 25 μm as a reference value, a mesh opening of 25 μm (500 mesh in the JIS standard) is used. Then, the product that has passed through the sieve is made into fine particles, and the product that remains on the sieve is made into coarse particles.

More specific examples of the above-described embodiments will be described.

The grades of chloride residue, tailing, floating ore, etc. were measured by alkali melting-ICP emission spectroscopy (ICP-AES, manufactured by Seiko Instruments Co., Ltd., SPS7700). The constituent amounts of each element in the solution were measured by ICP emission spectroscopic analysis method ICP-AES, manufactured by Seiko Instruments Co., Ltd., SPS7700).

5. Example 1 (Flotation)
5-1. The residue chloride residue chloride, in a furnace for recovering titanium tetrachloride volatilized in titanium smelting, as a solid, which is recovered substance after slow cooling is air. The chloride residue was obtained from Toho Titanium Co., Ltd. Then, the quality of the chloride residue was measured before the next flotation step (FIG. 4). Further, the chloride residue was in a slurry state after being washed with water.

5-2. Flotation conditions Flotation was performed on the chloride residue whose grade was measured under the following conditions.
Pulp concentration 300dry-g / L
Frothation time 15 minutes Frothation pH 4-5 (implemented unadjusted)
Floth flotation temperature Normal temperature collector 100 g / t (kerosene)
Foaming agent 200g / t (pine oil)
Air blowing amount 1-2L / min ・ L

The components of the tailing, flotation, and post-flotation liquid obtained after flotation were measured. The result is shown in FIG. Ti, C and Si were contained in the chloride residue before the flotation step. After the flotation process, most of C (coke) was distributed to the flotation (distribution rate of about 80%). Therefore, it is possible to recover Ti after removing C (coke) and the like. On the other hand, Si was distributed to Tailings at the same distribution rate as Ti.

6. Example 2 (table selection)
Froth flotation was performed in the same manner as above.

After flotation, the taillings were recovered, leached with 4M HCl, and the residue was subjected to specific gravity sorting. A table sorter was used for specific gravity sorting (test Wilfrey table beneficiation machine manufactured by Ota Kikai Seisakusho, model number 0-WCT1000 1000 mm x 500 mm). The amplitude was set to 7.5 mm, the rotation speed was set to 300 rpm, and the shower water volume was set to 6 L / min. The angle of attack of the table was set to 5 °, 3.5 °, and 2 °. As shown in FIG. 3, seven collection spots were provided on the lower edge side of the table. The width of the spot is as follows.
Spot 1: Width 27 cm
Spot 2: Width 33 cm
Spot 3: Width 30 cm
Spot 4: Width 25 cm
Spot 5: Width 20 cm & height 23 cm
Spot 6: Height 30 cm
Spot 7: Height 27 cm

_{The contents of TiO 2} and SiO ₂ at each angle of attack and at each recovery spot were measured using an alkaline melting-ICP emission spectroscopic analysis method (ICP-AES, manufactured by Seiko Instruments Co., Ltd., SPS7700). The results are shown in FIG. 5 (angle of attack 5 °), FIG. 6 (angle of attack 3.5 °), and FIG. 7 (angle of attack 2 °), respectively.

Referring to FIG. 5, gravity separation prior to TiO ₂ content of from Whereas was 75%, of TiO ₂ content in the recovery spot 3 and the collecting spot 4 is increased to 78% and 80%. On the other hand, gravity separation prior to SiO ₂ content of from Whereas was 10%, SiO ₂ content ratio in the recovery spot 3 and the collecting spot 4 reaches 7% and 10%.

Referring to FIG. 6, _{the content of TiO 2} before specific gravity sorting was 75%, whereas it increased to 80% at the recovery spot 4. In addition, more TiO ₂ could be distributed to the recovery spot 4 (distribution rate 61.2%). On the other hand, _{the content of SiO 2} before the specific gravity sorting was 10%, whereas _{the content of SiO 2 in} the recovery spot 4 was 9%.

Referring to FIG. 7, gravity separation prior to TiO ₂ content of from Whereas was 75%, the content of TiO ₂ is 83% in the recovery spot 5 and the collecting spot 6 was increased to 92%. On the other hand, while the gravity separation before SiO ₂ content ratio was 10%, SiO ₂ content ratio in the recovery spot 5 and the collecting spot 6 became 6% and 3%.

By performing specific gravity sorting in this way, the quality of Ti can be improved. In some cases, _{the amount of SiO 2} can be reduced.

7. Example 3 (Exclusion of Si etc. by classification)
Chloride residue is dust recovered as a solid in a furnace for recovering titanium tetrachloride volatilized in titanium smelting. The chloride residue was obtained from Toho Titanium Co., Ltd. Further, the chloride residue was in a slurry state after being washed with water.

The chloride residue was classified. Specifically, it was carried out as follows according to the procedure of "JIS Z 8815-1994 General rules for sieving test method".
(1) Stack the sieves with large openings so that they are on the top.
(2) Put the sample in the uppermost sieve and cover it.
(3) The sieving device (AS200 manufactured by Retsch) is operated at "Amplitude: 1.00".
(4) Sprinkle water in the shower and sieve until the liquid from the bottom is clear.
(5) Remove the sieve from the device.
(6) The sample is collected, filtered and weighed.
The results are shown in FIG. As a result of classification, it was shown that in the chloride residue, the particle group passing through the sieve having a mesh size of 25 μm accounts for about 20% of the whole. It was also shown that the group of particles that passed through a sieve with a mesh size of 38 μm accounted for about 22% of the total, and the group of particles that passed through a sieve with a mesh size of 53 μm accounted for about 35% of the total.

Next, each classified particle group was weighed. Then, elemental analysis on Ti and Si of each particle group was performed. Elemental analysis of each particle group used alkali melting-ICP emission spectroscopic analysis (ICP-AES, manufactured by Seiko Instruments Co., Ltd., SPS7700). The results are shown in FIG. In the table, the distribution ratio "+150" represents a group of particles remaining on a sieve having a mesh size of 150 μm. Further, "-25" represents a group of particles that have passed through a sieve having a mesh size of 25 μm. Further, "150/106" represents a group of particles that have passed through a sieve having a mesh size of 150 μm and remain on a sieve having a mesh size of 106 μm. It was shown that about 9% of Ti was present in the particle swarm that passed through a 25 μm sieve. Similarly, about 30% of Si was shown to be present in the particle swarm that passed through a 25 μm sieve. Therefore, by classifying with 25 μm as the reference value, _{the amount converted to TiO 2} / (TiO ₂ + SiO ₂ ) can be improved. Therefore, if the classification is performed in advance according to a predetermined reference value, the Si content can be reduced when Ti is recovered. That is, the quality of Ti in the recovered product after specific gravity sorting can be further improved.

Claims (4)

A method for recovering Ti from a chloride residue in titanium smelting .
A step of classifying the chloride residue into coarse particles and fine particles, and
A step of performing a flotation treatment on the coarse grains to obtain a tailling, a flotation, and a liquid after flotation.
A step of performing specific gravity sorting on the tailing and thereby removing Si ,
The method comprising. A method for recovering Ti from a chloride residue in titanium smelting.
The process of performing flotation treatment on the chloride residue to obtain tailing, flotation, and post-flotation liquid.
The process of classifying the taillings into coarse grains and fine grains, and
A step of performing specific gravity sorting on the coarse grains and thereby removing Si,
The method comprising. The method according to claim 1 or 2 , wherein the specific gravity sorting is a wet specific gravity sorting using a table sorter. The method according to any one of claims 1 to 3, further comprising a step of recovering a fraction _{having a TiO 2} / (TiO ₂ + SiO ₂ ) of 0.90 or more after the specific gravity sorting.