JP2733067B2 - Method for producing inorganic halogen compound powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a method for producing an inorganic halogen compound powder which is industrially useful in applications such as catalysts, reagents, photographic materials, and battery materials.

(Prior art) Conventionally, as a general production method of inorganic compound powder,
From a purified solution of an inorganic halogen compound, a method is employed in which a solvent is appropriately evaporated by various methods to recrystallize, and a separated solid is dried (hereinafter, this method is referred to as "recrystallization method"). .

However, in the case of the recrystallization method, the production efficiency is extremely low particularly when producing salts having high solubility in a solvent among inorganic halogen compounds, and furthermore, the storage and treatment of the mother liquor discharged in the solid separation step become complicated. However, there is also a problem that heavy metal salts sometimes become a source of pollution.

To solve the problem of this recrystallization method,
There is a method using a vacuum concentrator described in JP-A-52-38272. According to this method, the entire amount of the target inorganic halogen compound can be obtained as a solid from the solution containing the inorganic halogen compound in one operation, so that the inorganic halogen compound can be efficiently produced. Furthermore, a solid substance of the inorganic halogen compound can be obtained from the solution by a single apparatus, and a solid separation step is not required, so that there is no generation of a mother liquor as in the recrystallization method, and thus, the method is excellent in environmental protection. That's the way you are.

However, this method has an insufficient quality depending on a target product, and there is room for further study.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems and efficiently produces an inorganic halogen compound powder capable of obtaining a high-quality inorganic halogen compound powder with a very small amount of residual solvent. The aim is to provide a method.

[Constitution of the Invention] (Means for Solving the Problems and Action) The inventors of the present application focused on the vacuum concentrator described in JP-B-52-38272, and studied a method for concentrating and drying an inorganic halogen compound solution. Was done. As a result, when the concentration of the solution of the inorganic halogen compound is simply dried using the above-described apparatus, "turbidity" is generated in a solution quality test performed by dissolving the obtained inorganic halogen compound in a solvent such as water or alcohol. Was remarkable, it was found to be unsuitable as an industrial material. Therefore, as a result of further study, they found that by adjusting the pH of the solution of the inorganic halogen compound, it was possible to efficiently produce a high-quality inorganic halogen compound powder without "turbidity", and completed the present invention. Was.

The production method of the inorganic halogen compound powder of the present invention is pH
The inorganic halogenated compound solution adjusted to 4 or less, a long tubular heater, a vacuum evaporator and a receiver connected to the vacuum evaporator via a connecting pipe, and further comprising a vacuum pump connected to the receiver. It is characterized by being concentrated and dried by a vacuum concentrator.

As the inorganic halogen compound solution used in the present invention, a solution obtained by appropriately purifying an inorganic halogen compound solution produced by a known method by a method such as excess or activated carbon adsorption treatment as necessary can be used. Further, a solvent in which the solvent is preliminarily evaporated, or a slurry in which crystals are partially precipitated by further evaporating the solvent can be used. The solution referred to in the present invention is a solution of a solvent capable of dissolving an inorganic halogen compound such as water.

As inorganic halogen compounds, zinc bromide, cupric bromide, rubidium bromide, calcium bromide, potassium iodide,
Examples thereof include sodium iodide. Among these inorganic zinc compounds, zinc bromide, cupric bromide or rubidium bromide among these are more concentrated when applying the production method of the present invention, and the quality of the obtained product is good. Therefore, zinc bromide is more preferable for the same reason.

The pH of the inorganic halogen compound solution needs to be 4 or less, and preferably 3 or less. If the pH exceeds 4, the aqueous solution or alcohol solution of the obtained product becomes turbid and becomes unsuitable as a product.

Although the lower limit is not particularly limited as long as the pH is 4 or less, the amount of the acid used is preferably 5% by weight or less, preferably 3% by weight or less in the inorganic halogen compound solution in consideration of the yield. More preferably,

Examples of the acid used for adjusting the pH include mineral acids such as hydrobromic acid, hydrochloric acid and hydroiodic acid.

The vacuum concentrator used in the present invention comprises a long tubular heater, a vacuum evaporator, a receiver connected to the vacuum evaporator via a connecting pipe, and a vacuum pump connected to the receiver. It is.

As this vacuum concentrator, specifically, JP-B-52-38
No. 272, a vacuum concentrating device can be used. The figure shows an outline of the device described in the above publication. In the figure, 1 is a storage tank of an inorganic halogen compound solution, 2 is the solution, 3
Is a supply pump of the solution, 4 is a long heater, 5 is a vacuum evaporator, 6 is an intermediate valve, 7 is a connecting pipe, 8 is a receiver, 9 is a take-out valve, 10 to 12 are valves, and 13 is a pipe. (Vacuum system) and 14 are auxiliary vacuum pumps.

Although the material constituting such a vacuum concentrator is not particularly limited, it is preferable to select a material having a particularly high corrosion resistance at a portion which comes into direct contact with the inorganic halogen compound solution. Examples of the material having high corrosion resistance include glass, ceramics, synthetic resins such as fluororesins, metals having high corrosion resistance, and materials surface-treated with these materials.

The size, use conditions, and the like of the vacuum concentrator used in the present invention can be appropriately determined depending on the intended production capacity, the type of the solvent of the inorganic halogen compound solution, and the like.

The production of the inorganic halogen compound powder can be performed, for example, as follows.

First, the inorganic halogen compound solution 2 is sent to the long heater 4 at a constant flow rate by the supply pump 3, where it is preheated. The heating temperature at this time is not particularly limited, but it is preferable to heat the solution to the boiling point or higher. Next, the preheated solution is sent to a vacuum evaporator 5 to evaporate water. The evaporated solvent is removed from the pipe 13, and the inorganic halogen compound powder is accumulated in the receiver 8. It is preferable to perform this series of operations in an atmosphere of dried air, nitrogen, or the like, because the concentration efficiency can be further increased.

According to the production method of the present invention, the details of the mechanism capable of obtaining an inorganic halogen compound in which the solution when dissolved in a solvent such as water is clear and the amount of the residual solvent is extremely small are unknown, but the inorganic halogen compound solution It is presumed that the acid present in the medium in excess slightly promotes dehydration and contributes to the stabilization of product quality.

(Examples) Hereinafter, the present invention will be described specifically with reference to Examples.
The present invention is not limited by these examples. In the following, “%” represents “% by weight”. In addition, the measurement of pH, the amount of the remaining solvent and the dissolution test were performed by the following methods.

pH Measurement The pH was measured by placing a 50 ml sample in a 50 ml glass beaker and measuring according to JIS Z 8802 (pH measurement method).

Residual solvent amount The residual solvent amount was measured in accordance with the method of JIS K068 (method for testing moisture of chemical products). When measuring, take 1 g of the sample in a volumetric flask, add methyl alcohol to make 100 ml, homogenize, then test using 2 ml of this solution to determine the amount of residual solvent, and simultaneously perform a blank test using 2 ml of methyl alcohol. The amount of the solvent was determined, and the amount of the residual solvent in the product was determined from the difference between the two.

Dissolution test The dissolution test was performed according to JIS K8001 (General rules for reagent test method) 5-2 dissolution test using water and ethanol as a solvent. Note that the measurement was performed after dissolving the sample using a 5 g sample to make 50 ml by adding a solvent. The evaluation method is as follows.

：: clear ○: almost clear △: slightly clear ×: slightly turbid XX: turbid Example 1 First, each purified aqueous solution of zinc bromide, cupric bromide and rubidium bromide was prepared by the following method. That is, each of zinc oxide, cupric oxide and rubidium monoxide,
The resulting solution was allowed to react with a hydrobromic acid aqueous solution (48%) at a predetermined molar ratio, and the solution after the reaction was adjusted to pH 4 to 6, and the solution was naturally filtered (paper: using Toyo Paper No. 5C). Next, the concentration of the inorganic halogen compound in each of these purified aqueous solutions was adjusted to a concentration of 50% by weight, and the pH thereof was further adjusted as shown in Table 1. Each obtained aqueous solution 1 was concentrated and dried by a vacuum concentrator to obtain an inorganic halogen compound powder.

The apparatus described in JP-B-52-38272 was used as a vacuum dryer.

The concentration and drying were performed while continuously supplying the aqueous solutions by the supply pump 8 at a rate of 0.11 / min. The temperature of the long heater 4 for supplying each solution is 180 ° C.
The heating temperature of the jacket was set at 120 ° C., and the degree of reduced pressure in the receiver 8 was set at 10 mmHg. The concentrated and dried product was taken out after continuing the drying in the receiver for another 10 minutes after the completion of sending each aqueous solution. The time required for concentration and drying was 20 minutes.

The residual solvent amount and the like of each of the inorganic halogen compound powders thus obtained were measured. The results are shown in Table 1.

Comparative Example 1 Each inorganic halogen compound powder was prepared in the same manner as in Example 1 except that the pH of each purified solution of zinc bromide, cupric bromide and rubidium bromide in Example 1 was adjusted as shown in Table 1. I got Table 1 shows the measurement results of the quality of the powder.

Comparative Example 2 An inorganic halogen compound powder was produced by a recrystallization method.

First, 500 ml each of the aqueous solutions of zinc bromide, cupric bromide and lividium bromide used in Example 1 whose pH was adjusted as shown in Table 1 were placed in a rubbed flask. Next, the eggplant-shaped flask was attached to a reduced-pressure evaporator, the degree of reduced pressure was set to 5 mmHg, and the eggplant-shaped flask was heated while rotating. Heating was performed using an oil bath, and the temperature was gradually raised so that the solution in the eggplant-shaped flask did not boil off, and water was evaporated at 70 to 140 ° C. Finally, at the stage when almost no solvent was recognized, the slurry-like solution in the formed flask was subjected to solid-liquid separation by applying reduced pressure. Thereafter, the obtained solid was dried at a reduced pressure of 5 mmHg and a temperature of 120 ° C. for 1 hour or 2 hours to obtain a powder of each inorganic halogen compound.

 Table 1 shows the quality measurement results for each powder.

Example 2 Inorganic halogen compound powders were obtained in the same manner as in Example 1 by using aqueous solutions of calcium bromide, cobalt bromide, sodium iodide and potassium iodide, each of which had the pH adjusted as shown in Table 2. Was.

 Table 2 shows the quality measurement results for this powder.

Comparative Example 3 An inorganic halogen solution was prepared in the same manner as in Example 2 except that the pH of each aqueous solution of calcium bromide, cobalt bromide, sodium iodide and potassium iodide was adjusted as shown in Table 2. Compound powder was obtained.

 Table 2 shows the quality measurement results for this powder.

[Effects of the Invention] According to the production method of the present invention, it is possible to efficiently obtain a high-quality inorganic halogen compound powder having a good solubility in a solvent such as water and a very small amount of a residual solvent.

[Brief description of the drawings]

 The figure is a schematic diagram of a vacuum concentrator.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication location C01F 11/34 C01F 11/34 C01G 3/04 C01G 3/04 9/04 9/04 51/08 51/08

Claims (2)

(57) [Claims] 1. An inorganic halogenated compound solution adjusted to pH 4 or less is supplied to a long tube heater, a vacuum evaporator, a receiver connected to the vacuum evaporator via a connecting pipe, and a vacuum connected to the receiver. A method for producing an inorganic halogen compound powder, comprising concentrating and drying with a vacuum concentrator equipped with a pump. 2. The method for producing an inorganic halogen compound powder according to claim 1, wherein the inorganic halogen compound is one compound selected from zinc bromide, cupric bromide and rubidium bromide.