WO2005035446A1

WO2005035446A1 - Method for producing aqueous solution of chlorination product of zirconium

Info

Publication number: WO2005035446A1
Application number: PCT/JP2004/015028
Authority: WO
Inventors: Hiroshi Sugii; Yasushi Nakajima; Atsushi Kumakura
Original assignee: Daiichi Kigenso Kagaku Kogyo Co., Ltd.
Priority date: 2003-10-14
Filing date: 2004-10-12
Publication date: 2005-04-21
Also published as: ZA200603819B; AU2004279711A1; AU2004279711B2; JP4403451B2; JP2005119895A

Abstract

A method for producing an aqueous solution of chlorination products of zirconium which comprises: (1) the step 1 of leaching an alkali-treated zircon sand with water, followed by filtration, to prepare a water-leached cake, (2) the step 2 of adding hydrochloric acid to the water-leached cake and drying the resultant gel or of adding hydrochloric acid to the water-leached cake and spray-drying the resultant slurry before gelling, to thereby prepare a dried intermediate, (3) the step 3 of adding hydrochloric acid to the dried intermediate, to prepare a suspension, wherein the hydrochloric acid is added in such a manner that the resultant suspension has a zirconium chlorination product concentration of 5 to 16 mass % in terms of ZrO2 and a free HCl concentration of 1 to 10 mass %, and (4) the step 4 of filtrating the above suspension to prepare the aqueous solution of chlorination products of zirconium. The above method can be employed for producing, form an alkali-treated zircon sand, an aqueous solution of chlorination products of zirconium which is reduced in a silica content, with the period of time required for the production being less than that in a conventional method.

Description

Specification

Method for producing aqueous solution of zirconium chloride

Technical field

The present invention relates to a method for producing an aqueous solution of zirconium chloride.

Background art

[0002] A zirconium chloride aqueous solution is a raw material for producing various zirconium compounds such as zirconium oxychloride, zirconium hydroxide, and basic zirconium sulfate. Of these, zirconium oxychloride (hereinafter sometimes referred to as “zoc”) is particularly useful as a starting material for zirconium ceramics.

[0003] An aqueous solution of zirconium chloride is generally prepared by melting or heating a zircon sand with an alkali agent or by hydrothermal treatment, and leaching the resulting reaction product (mixture) with water to form an alkali silicate. Was dissolved in water, followed by filtration to obtain a water-infused cake (dehydrated cake) containing zirconium hydroxide as a main component, which was subjected to extraction treatment with hydrochloric acid to obtain an aqueous solution of zirconium chloride. It is produced by insolubilizing the silica component and filtering.

[0004] As an improvement technique of this production method, for example, a water-leached cake is dissolved in concentrated hydrochloric acid in a temperature range of 60 to 100 ° C, and gelatin of 0.2-1. There is known a method in which the silica is separated by coagulation and sedimentation and separated by filtration. However, in this production method, there are problems such as poor filterability of hydrous silica (gel silica and insoluble silica) and dissolution of silica in an aqueous chloride solution. Further, the insoluble silica is in a gel state and therefore has a high volume and contains a considerable amount of zirconium, which causes a reduction in the recovery rate of zirconium.

[0005] Technical capabilities for improving the above problems, for example, disclosed in Patent Document 1 and Patent Document 2. Patent Document 1 discloses that i) a step of mixing fine-particle zirconium silicate and an alkali and subjecting them to a hydrothermal treatment at a boiling point or higher, ii) a solid-liquid separation of the slurry obtained in the hydrothermal treatment step, and Iii) a step of dispersing the solid content separated and returned in water and subjecting it to heat treatment, and Iv) a step of subjecting the solid content obtained by solid-liquid separation of the neutralized slurry to hydrochloric acid treatment to elute soluble components; A process for obtaining an acidic aqueous solution of zirconium-zirconium, and vi) a step of concentrating the acidic aqueous solution to crystallize zirconium octahydrate octahydrate to obtain the same. Have been.

[0006] Patent Document 2 discloses a method of producing an aqueous zirconium salt solution by extracting a water-infused cake obtained by leaching an alkali-treated product of zircon sand with water and extracting the resulting product with hydrochloric acid. Water was added to the cake to form a slurry. Hydrochloric acid was added to the slurry while stirring the slurry, and the zirconium chloride concentration in the liquid phase of the resulting suspension was 9%.

A method for producing an aqueous solution of zirconium chloride is disclosed, which comprises kneading so as to have a concentration of 211 wt% and a free HC1 concentration of 17 wt%, followed by filtration.

[0007] Then, according to the technology disclosed in these documents, an aqueous solution of zirconium salt and zirconium oxy salt containing less silica are obtained.

[0008] However, there is still room for further improvement in the technologies disclosed in these documents. For example, in the technique described in Patent Document 1, the dispersion cake after alkali decomposition is subjected to neutralization with hydrochloric acid, followed by solid-liquid separation, followed by re-dispersion and extraction with hydrochloric acid. For this reason, there are problems that the filtration process is performed three times, the process time is long, and the power is low. In the technique described in Patent Document 2, hydrochloric acid is slowly added quantitatively to the dispersion cake after alkali decomposition to neutralize it, neutralized, and after neutralization, solid-liquid separation is performed again through addition of hydrochloric acid, and zirconium salt is added. An aqueous solution is obtained. The resulting aqueous zirconium chloride solution has a low silica content and a high yield, but has the problem that it takes a long time to extract the zirconium with the addition of hydrochloric acid. Furthermore, the techniques of Patent Documents 1 and 2 have a problem that the process time required to obtain an aqueous solution of zirconium salt is long and production efficiency is poor.

Patent Document 1: JP-A-3-265519

Patent Document 2: Japanese Patent No. 3427211

Disclosure of the invention

Problems to be solved by the invention

[0009] The present invention provides a method for removing silica from an alkali-treated zircon sand in a shorter time than the conventional method. It is a main object of the present invention to provide a method for producing an aqueous solution of zirconium chloride with a low content of zirconia.

Means for solving the problem

[0010] The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that a specific method for producing an aqueous zirconium chloride solution can achieve the above object, and have completed the present invention.

[0011] That is, the present invention relates to the following method for producing a zirconium chloride aqueous solution.

1. A method for producing an aqueous solution of zirconium salted sardine having the following steps:

(1) a process of leaching an alkali-treated zircon sand with water and then filtering to obtain a water-leached cake 1,

(2) The ability to dry the gel obtained by adding hydrochloric acid to the water leached cake, or by spray drying the slurry obtained by adding hydrochloric acid to the water leached cake before gelling.

Step 2 of obtaining a dried intermediate

(3) a step of obtaining a suspension by adding hydrochloric acid to the dried intermediate, wherein the concentration of zirconium chloride in the liquid phase of the obtained suspension is 5-16% by mass in terms of ZrO, and Free H

2

Process of removing hydrochloric acid so that the C1 concentration becomes 110% by mass 3,

(4) Step 4 of obtaining an aqueous solution of zirconium chloride by filtering the suspension.

2. The production method according to the above item 1, wherein in the step 2, the slurry is spray-dried at 100 to 300 ° C to obtain a dry intermediate having a moisture content of 0 to 15% by mass.

3. The production method according to the above item 1, wherein in step 2, the gel is dried with stirring at 60 to 150 ° C. to obtain a dry intermediate having a moisture content of 0 to 15% by mass.

4. A zirconium chloride aqueous solution produced by the production method according to any one of the above items 13 to 13.

Hereinafter, the method for producing the aqueous solution of zirconium salt ridges of the present invention will be described in detail.

[0012] The method for producing an aqueous solution of zirconium salted product of the present invention includes the following steps 114:

(1) A step of obtaining a water-leached cake (dehydrated cake) by leaching an alkali-treated product of zircon sand with water and then filtering it.

(2) The ability to dry the gel obtained by adding hydrochloric acid to the water leaching cake, or the water leaching cake By spray drying the slurry obtained by adding hydrochloric acid to the

Step 2 of obtaining a dried intermediate

2

Hereinafter, the production method of the present invention will be described by dividing it into individual steps.

(Step 1)

In step 1, a water-leached cake is obtained by subjecting an alkali-treated zircon sand to leaching treatment with water and then filtering.

The alkali-treated product of zircon sand (hereinafter sometimes abbreviated as “alkali-treated product”) is not particularly limited. Generally, a mixture of zircon sand (Zr sand) with caustic soda and Z or sodium carbonate is used. Those obtained by high-temperature heat treatment (alkali melting) or hydrothermal treatment can be used.

[0015] The component of the alkali-treated product is at least one of sodium zirconate, sodium silicate zirconate, sodium silicate, and unreacted zircon sand, which generally varies depending on the conditions of the alkali treatment. The following is an example of a reaction presumably caused by the alkali treatment. D ZrSiO + 6NaOH → Na ZrO + Na SiO + 3H O

4 2 3 4 4 2

2) ZrSiO + 2NaOH → Na ZrSiO + H O

4 2 5 2

3) ZrSiO + 2Na CO → Na ZrO + Na SiO + 2CO †

4 2 3 2 3 2 3 2

4) ZrSiO + Na CO → Na ZrSiO + CO †

4 2 3 2 5 2

The production method of the present invention can be suitably applied to an alkali-treated zircon sand obtained by alkali treatment under any conditions. That is, the present invention can be suitably applied to the Al-treated products included in the above-described ranges and other alkali-treated products.

[0016] The method of leaching the alkali-treated product with water is not particularly limited as long as the alkali silicate contained in the alkali-treated product can be dissolved in water. For example, a method of immersing the alkali-treated product in water, a method of mixing the alkali-treated product and water, and the like can be given. The amount of water is not particularly limited as long as the alkali silicate can be sufficiently dissolved. . The temperature of the water is not particularly limited, either, and can be appropriately set according to the type of the alkali treatment product, the leaching method, the amount of water, and the like.

[0017] After the leaching treatment, a treated product (a mixture of an alkali-treated product and water) is filtered, and water in which an alkali silicate is dissolved is separated to obtain a water-leached cake (a dehydrated cake). The composition of the water leached cake varies depending on the composition of the alkali-treated product as described below.

For example, in the case of an alkali-treated product obtained by the above formulas 1) and 3), sodium zirconate is hydrolyzed by leaching treatment with water to produce zirconium hydroxide and caustic soda. The amount of water used for the leaching treatment is not particularly limited as long as it can sufficiently hydrolyze the sodium zirconate. By filtration, sodium silicate and excess alkali are removed to obtain a water leached cake containing zirconium hydroxide as a main component. The filtration method is not particularly limited, and is, for example, an ordinary filtration method using a filter press, a vacuum suction filter, a precoat pressure filter, or the like. Batch or continuous filters can be used for the filter.

[0019] In the case of the alkali-treated product obtained by the above formulas 2) and 4), sodium silicate and excess alkali are dissolved in water by leaching treatment with water. The amount of water used for the leaching is not particularly limited as long as it can dissolve soda silicate and excess alkali sufficiently. By filtration, sodium silicate and excess alkali are removed to obtain a water leached cake containing sodium silicate zirconate as a main component. The filtration method is the same as above.

[0020] The water leached cake generally contains at least one of zirconium hydroxide, sodium zirconate, sodium zirconate and unreacted zircon sand. Although the approximate composition is not limited, it is generally ZrO: 30 to 50% by mass, Na: 3 to 10% by mass, SiO: 1

2 2 2 1 8 mass

%.

[0021] The water content of the water-leached cake is not particularly limited, but is usually 10 to 50% by mass, and preferably 1 to 50% by mass.

About 5-40% by mass.

[0022] In the production method of the present invention, a water leached cake outside the above-mentioned range may be obtained and subjected to a subsequent step to obtain a zirconium chloride aqueous solution.

(Step 2)

In step 2, the force to dry the gel obtained by adding hydrochloric acid to the water leached cake, or A slurry obtained by adding hydrochloric acid to the water-leached cake is spray-dried before gelling to obtain a dry intermediate. In either case, of course, the water-leached cake may be heated with hydrochloric acid.

As described above, in step 2,

A) A dry intermediate may be obtained by drying the gel obtained by adding hydrochloric acid to the water-leached cake, or

Mouth) A dried intermediate may be obtained by spray-drying the slurry obtained by adding hydrochloric acid to the water-leached cake before gelling.

[0024] In either of the above methods, the hydrochloric acid concentration is not particularly limited, but it is preferable to dilute with water before use. In such a case, the concentration may be generally 5 to 16%, preferably about 8 to 15%. When the hydrochloric acid concentration is less than 5% or more than 16%, the extraction rate of zirconium decreases in both cases, which is not preferable (see Fig. 1).

[0025] The amount of hydrochloric acid to be added is not particularly limited, but usually the molar ratio of HClZZrO is 1.5 to 2.5.

2

Degree, preferably about 2 to 2.2. When the molar ratio is less than 1.5, the SiO2 in ZOC produced using the aqueous solution of zirconium chloride obtained by the production method of the present invention as a raw material is used.

2

ZZrO (ie, the content of the impurity SiO) is low, but zirconium extraction

twenty two

This is not preferable because the rate (yield) decreases. When the molar ratio exceeds 2.5, the amount of Si 2 O 3 / ZrO in ZOC produced from the aqueous solution of zirconium salt obtained by the production method of the present invention becomes low, and the zirconium extraction rate also improves. Force excess hydrochloric acid remains

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Not economical (see Figure 2).

[0026] In the case of a), as a method of drying the gel-like material, a drying method capable of uniformly drying the silica sol is desirable. Therefore, in the method of allowing the gel to stand and dry, the surface and the central portion are unevenly dried, and the yield of zirconium may be reduced in the subsequent hydrochloric acid extraction. That is, a method that can uniformly dry the silica sol is desired. For example, a drying method such as a paddle type, a fluidized bed type, or a Nauter type can be adopted. The gel is preferably dried with stirring (ie, vigorously).

[0027] The drying temperature is not particularly limited, and is usually about 60 to 150 ° C, preferably about 80 to 110 ° C. If the drying temperature is too low, the drying may be insufficient. High drying temperature If it is too much, the extraction rate of Zr during the subsequent extraction of hydrochloric acid may decrease.

[0028] The moisture content of the dried intermediate obtained by drying is not particularly limited, but is usually 0 to 15% by mass.

%, Preferably about 2 to 8% by mass. If the water content is more than 15% by mass, it is not preferable because the filterability in the later step deteriorates.

[0029] The drying time is not particularly limited, and may be appropriately adjusted in consideration of a drying method, a drying temperature, and the like so that a dried intermediate having a desired moisture content is obtained.

[0030] The obtained dried intermediate is preferably pulverized to about 10 to 200 m. By pulverizing, the extraction rate of zirconium by the hydrochloric acid-added kneader in step 3 can be increased.

[0031] In the case of mouth, hydrochloric acid is first added to the water-leached cake to prepare a slurry. The hydrochloric acid concentration and the amount added are the same as in the case of the above a). Then, spray drying is performed before the slurry is gelled. Spray drying conditions are not particularly limited, and may be in accordance with a conventional method. For example, the inlet temperature is 100 to 300. C, preferred <150-250. The temperature may be set at about C, the disk rotation speed is about 300 00-50000 rpm, and the outlet temperature is about 75-115 ° C.

[0032] The average particle diameter of the obtained dry intermediate (fine particles) is not particularly limited, but may be generally about 10-20 O / zm. The moisture content of the dried intermediate is the same as in the above case a). The method of mouth) is suitable for industrial operation because the dried intermediate can be obtained in a shorter time than the method of a).

[0033] In the production method of the present invention, in step 2, in order to dry the gel or slurry into a dried intermediate, the silica precipitation rate and the precipitated silica particles in the hydrochloric acid extract in step 3 are described later. Filterability and the like can be improved. As a result, in step 4, a high-purity aqueous solution of zirconium chloride is obtained with a small amount of dissolved silica. The reason for obtaining the above results is probably that once a dry intermediate is used, polymerization, agglomeration, dehydration, etc. of the silica component are promoted, and silica particles (SiO

2

形態) The formation of a SiO polymer with a different form from that of

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Conceivable.

(Step 3)

In step 3, hydrochloric acid is added to the dry intermediate to obtain a suspension. Specifically, the resulting suspension The zirconium salt concentration in the liquid phase of the liquid is 5-16% by mass in terms of ZrO, and

2

Then, the hydrochloric acid is removed so that the free HC1 concentration becomes 110% by mass.

[0034] In step 3, hydrochloric acid is added to the dry intermediate (of course, the dry intermediate may be added to hydrochloric acid.

) To extract zirconium.

[0035] The hydrochloric acid concentration is not particularly limited, but it is preferable to use it after dilution with water. In such a case, the concentration may be usually 5 to 16%, preferably about 8 to 15%. Setting the concentration in a vigorous concentration range can increase the zirconium extraction rate.

[0036] As the amount of hydrochloric acid added, the concentration of zirconium chloride in the liquid phase of the obtained suspension in terms of ZrO is 5 to 16% by mass and the concentration of free HC1 is 110 to 10% by mass. Inside

2

If it is, there is no particular limitation. ZrO-equivalent concentration of zirconium salted sardine is less than 5% by mass

2

In the case of (1), the amount of the solution increases, which is not preferable. If the amount exceeds 16% by mass, crystals of ZOC may precipitate when the temperature of the solution decreases, which is not preferable. If the concentration of free HC1 is less than 1% by mass, the extraction efficiency of zirconium is not sufficient. If it exceeds 10% by mass, excess hydrochloric acid remains, which is not economical.

[0037] The suspension obtained is preferably subjected to a heat treatment before the force filtration in which the suspension can be directly transferred to step 4 (filtration step). By performing the heat treatment, the extraction rate of zirconium can be improved.

[0038] The heat treatment conditions are not particularly limited, but the heating temperature is preferably 80 ° C or higher, more preferably 90 ° C or higher. If the temperature is lower than 80 ° C, extraction of zirconium may be insufficient. The heating time is preferably 30 minutes or more, more preferably 1 hour or more. If the time is less than 30 minutes, the extraction rate of zirconium may be insufficient. The upper limit of the heating time is not particularly limited, but the effect cannot be expected to be increased even if the heating time is extended to 2 hours or more. Therefore, the productivity should be limited to about 2 hours.

After the heat treatment, the suspension is preferably cooled to 70 ° C. or less. Cooling is also effective in reducing the amount of dissolved silica in the suspension. The lower the cooling temperature, the lower the solubility of the silica. If the cooling temperature is set too low while applying force, ZOC may precipitate, and the filterability may be reduced due to an increase in the viscosity of the suspension. Therefore, it is usually preferable to set the cooling temperature to about 50-60 ° C. t process 43

In step 4, an aqueous solution of zirconium chloride is obtained by filtering the suspension.

That is, in step 4, the suspension is subjected to solid-liquid separation to remove suspended components such as silica and zirconia sand (Zr sand) from the suspension. The solid-liquid separation method is not particularly limited, and for example, a usual filtration method using a filter press, a reduced pressure suction filter, a precoat pressure filter, or the like can be employed. The filter may be a batch type or a continuous type, and a shift may be used.

[0041] The temperature of the suspension at the time of filtration is not particularly limited, but is preferably about 70 ° C or lower, more preferably about 50-60 ° C. For example, after the suspension is prepared in step 3, the suspension is heated, then cooled to 70 ° C. or lower, preferably about 50-60 ° C., and then the filtration step of step 4 can be performed at the same temperature.

[0042] By adding a polymer flocculant to the suspension, filtration (solid-liquid separation) and removal of silica can be performed more effectively. Examples of the polymer flocculant include cationic polymethacrylate, polyamine, nonionic polyacrylamide, polyethylene oxide (hereinafter abbreviated as “PEO”), and polyvinyl alcohol. The amount of the polymer flocculant added is not particularly limited, but usually 0.5 to 5 parts by weight based on 100 parts by weight of SiO.

2

preferable. The method of addition is not particularly limited, but it is preferable to add the calorific value after dissolving the aqueous solution into a solution.

The invention's effect

According to the production method of the present invention, a zirconium chloride aqueous solution in which the content of silica is kept low can be produced effectively and efficiently from an alkali-treated zircon sand.

In particular, according to a preferred embodiment of the production method of the present invention, the time required for producing an aqueous zirconium chloride solution from an alkali-treated zircon sand can be reduced to about 1Z3 of the conventional method. Therefore, the production efficiency (process capability) of the aqueous solution of zirconium chloride can be greatly improved.

[0045] Further, the volume of the filtrate (solid) containing silica, which has a high zirconium extraction rate, is 1Z of the conventional method.

5-Can be reduced to about 1Z3.

Brief Description of Drawings FIG. 1 is a graph showing the relationship between Zr extraction rates when the hydrochloric acid concentration in step 1 was changed to 10, 15 and 25% under the conditions of Example 1.

[FIG. 2] Under the conditions of Example 1, the amount of hydrochloric acid added in step 1 was changed to 2, 2.1, 2.2 and 2.3 (molar ratio of HC1 / ZrO). Zirconium chloride aqueous solution

2

FIG. 4 is a diagram showing a relationship with a SiO 2 / ZrO ratio in a ZOC solution manufactured using as raw material.

twenty two

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

Example 1

The frit of the alkali-treated zircon sand was leached with water and filtered to obtain 1000 g of a water-leached cake (ZrO: 45% by mass, unreacted Zr sand: 4.3% by mass).

2

Next, a water leached cake was added to an aqueous solution obtained by diluting 1366 g (8.06 mol) of 18% hydrochloric acid with 1366 g of water, and the mixture was stirred to prepare a uniform slurry.

[0050] The slurry was put into a spray drier (hereinafter abbreviated as "SD") at a rate of 4KgZh and dried. The SD operating conditions were an inlet temperature of 200 ° C, a disk rotation speed of 40,000 rpm, and an outlet temperature of 75 ° C. This gave 1183 g of a dry intermediate. The moisture content of the dried intermediate was 4% by mass, and the particle size was 20-30 μm.

534 g of water and 229.7 g of 36% hydrochloric acid were sequentially added to a 1-L beaker, 400 g of a dry intermediate (ZrO: 142.2 g) was added (HCl / ZrO molar ratio: 2), and the mixture was stirred. After holding at 96 ° C for 1 hour,

twenty two

58.5 The mixture was cooled to 5 ° C, and 55.8 g of a 5% aqueous solution of PEO was added. After stirring for about 10 minutes and suction filtered through a blanking Funaroto (inner diameter 1 l _cm).

[0052] The filter cake was washed with 9% hydrochloric acid 200 g, and a residue 26 5 g of silica particles and unreacted Zr sand, ZrO: 10. 95 mass ^_0/0, SiO / ZrO (weight ratio): 0.0013 and Free HC1: 3.8

2 2 2

1,295 g of an aqueous solution of zirconium salted sardine consisting of 1% by mass was recovered. The Zr extraction rate was 99.7%. Table 3 shows the results.

[0053] Decoration 12

The frit of the alkali-treated zircon sand was leached with water and filtered to obtain 1000 g of a water-leached cake (ZrO: 45% by mass, unreacted Zr sand: 4.3% by mass). Next, a water-infused cake was added to an aqueous solution obtained by diluting 1300 g of water with 1634 g (8.06 mol) of 18% hydrochloric acid, and the mixture was stirred to prepare a gelled product.

[0055] The gelled product was taken out on a hot plate and dried while stirring at 110 ° C.

This resulted in 1163 g of dry intermediate. The moisture content of the dried intermediate is 4.8% by mass.

[0056] 520 g of water and 226.4 g of 36% hydrochloric acid were sequentially added to a 1-L beaker, 400 g of a dried intermediate (ZrO: 137.6 g) was added (HClZZrO molar ratio: 2), and the mixture was stirred. After holding at 96 ° C for 1 hour,

twenty two

[0057] The filter cake was washed with 9% hydrochloric acid 200 g, and a residue 26 5 g of silica particles and unreacted Zr sand, ZrO: 11. 05 mass ^_0/0, SiO / ZrO (weight ratio): 0.0012, Free HC1: 3.8 mass

2 2 2

1239 g of an aqueous solution of zirconium salted sardine having a high% power was recovered. The Zr extraction rate was 99.5%. Table 3 shows the results.

Comparative Example 1

A litter of alkali-treated zircon sand is leached in a 2 L beaker, filtered, and then 1000 g of water-leached cake (ZrO: 37% by mass, H0: 41.5% by mass, unreacted Zr sand: 9%)

twenty two

. Was 1 mass ^_0/0), and water 680g and mosquitoes卩tut slurry. The slurry pH was 13 (33 ° C). While stirring, 1215 g of 35% hydrochloric acid was added at a flow rate of 16 gZmin, and when the pH reached 6, the addition of hydrochloric acid was stopped and only stirring was performed for 30 minutes. Thereafter, the addition of hydrochloric acid was restarted, and when the addition of hydrochloric acid was completed, the slurry temperature was set to 90 ° C. After stirring at 90 ° C for 8 hours, the slurry temperature was cooled to 60 ° C. To the slurry after the heat treatment, 135 g of a 0.5% by mass aqueous PEO solution was added, and the mixture was stirred for 2 hours and suction-filtered with a Buchner funnel (20 cm in inner diameter).

The filter cake was washed with 550 ml of hot water, and 457 g of a cake composed of silica particles and unreacted Zr sand, ZrO: 11% by mass, free 1: 1: 4% by mass and 310 / ZrO (weight ratio): 0 . 0016 power

There were obtained 3344 g of an aqueous solution of zirconium salted sardine consisting of 222. The Zr extraction rate was 99.4%. Table 3 shows the results.

[0060] Comparative Example 2

In a 2L beaker, frit of alkali-treated zircon sand is leached with water and filtered. 1000 g of water-leached cake (ZrO: 37% by mass, H: 41.5% by mass, unreacted Zr sand: 9

twenty two

.1% by mass) and 500 g of water were dispersed by kneading and neutralized to pH 6 with hydrochloric acid. Then, after heat treatment for 2 hours, suction filtration was carried out through a Buchner funnel (inner diameter: 11 cm) to obtain 938 g of a neutralized cake. The neutralized cake was added to 1290 g of a 20% hydrochloric acid solution, and the mixture was heated and stirred at 90 ° C for 1 hour, cooled to 60 ° C, and filtered through a Buchner funnel (20 cm inside diameter). The filter cake is washed with 500 ml of warm water, and 487 g of a cake composed of silica particles and unreacted Zr sand, ZrO: 10.3 mass

2

%, Free HC1: 3% by mass and SiO 2 / ZrO (weight ratio): 0.0021

twenty two

219 lg of an aqueous chloride solution were obtained. The Zr extraction rate was 61%. Table 3 shows the results.

[0061] Comparative Example 3

After water leaching of a frit of an alkali-treated zircon sand into 1215 g of 35% hydrochloric acid, the water-leached cake obtained by filtering is 1000 g (ZrO: 37% by mass, H0: 41.5% by mass, unreacted Zr

twenty two

(Sand: 9.1% by mass) dispersed in 680g of water, stirred at 90 ° C for 8 hours, cooled to 60 ° C, and added with 135g of 0.5% by mass PEO aqueous solution. The slurry was filtered under the same conditions as described above. During filtration, filtration became impossible when about 20 g of the liquid was obtained.

[0062] Decoration 13-7

Table 3 below shows the results of experiments (Examples 3 and 4) in which the drying conditions were changed as shown in Table 1 below in Example 1.

[0063] [Table 1]

Note) SD drying temperature (° C) indicates “SD inlet temperature”

Table 3 below shows the results of the experiment (Examples 5-7) in which the drying conditions (temperature unit: ° C) in Example 2 were changed as shown in Table 2 below.

[Table 2] Drying intermediate Moisture content Experiment Drying temperature Drying method

Hot plate

Example 5 150 A 4.8

ί

Hot plate

Example 6 10 0 4 .6

Standing still

Hot plate

Example 7 8 0 ί 4

ί A α

[0066] [Table 3]

* Compared to required time: The time required for Example 1 was calculated as “1”.

Industrial applicability

[0068] The production method of the present invention is a method for effectively and efficiently producing an aqueous solution of zirconium chloride with a low silica content from an alkali-treated zircon sand.

[0069] In particular, in a preferred embodiment of the production method of the present invention, the time required for producing an aqueous solution of zirconium chloride from an alkali-treated zircon sand can be reduced to about 1Z3 of the conventional method. Significant increase in production efficiency (process capacity) of aqueous solution of zirconium salt Can be improved.

[0070] Further, the volume of the filtrate (solid) containing silica, which has a high zirconium extraction rate, is also 1Z of the conventional method.

5-Can be reduced to about 1Z3.

[0071] The aqueous solution of zirconium chloride zirconium produced by the production method of the present invention can be suitably used as a production raw material of oxychloride zirconium (ZOC), which is useful as a starting material for zirconium ceramics.

Claims

Claims [1] A method for producing an aqueous zirconium chloride solution comprising the following steps:

(2) The ability to dry the gel obtained by adding hydrochloric acid to the water leached cake, or spray drying the slurry obtained by adding hydrochloric acid to the water leached cake before gelling, drying Step 2, obtaining an intermediate

2

[2] In step 2, a slurry 100 - 300 ° C shall by spray-drying to obtain a dry intermediate moisture content 0-15 wt ^_0/0 The method according to claim 1.

[3] The production method according to claim 1, wherein in step 2, the gel is dried with stirring at 60 to 150 ° C to obtain a dry intermediate having a moisture content of 0 to 15% by mass.

[4] A zirconium chloride aqueous solution produced by the production method according to any one of claims 1 to 3.