WO2007144973A1

WO2007144973A1 - Method for purification of alkali metal carbonate solutions, purification apparatus and alkali metal carbonate solutions

Info

Publication number: WO2007144973A1
Application number: PCT/JP2006/322700
Authority: WO
Inventors: Shiroshi Matsuki
Original assignee: Tsurumi Soda Co., Ltd.
Priority date: 2006-06-16
Filing date: 2006-11-08
Publication date: 2007-12-21
Also published as: JP4956063B2; TWI331985B; TW200800801A; JP2007331993A

Abstract

The invention aims at providing a method for the purification of alkali metal carbonate solutions by which calcium compounds contained in alkali metal carbonates can be removed at a low cost without losing the alkali metal carbonates; a purification apparatus; and alkali metal carbonate solutions purified thereby. Specifically, a purified alkali metal carbonate solution is obtained by the step (S1) of dissolving an alkali metal carbonate (such as sodium carbonate) containing impurities such as calcium compounds in water heated to a suitable temperature, e.g., 30°C to prepare a solution having an alkali metal carbonate concentration of 15% by weight or above (e.g., 30% by weight), the step (S2) of keeping the aqueous solution to precipitate the impurities, and the step (S3) of separating the impurities from the solution with a filter or the like.

Description

,. Specification

Rukakari metal carbonate solution purification method, purification device, and Al force metal carbonate solution dermatology field

The present invention relates to a method for purifying an alkaline gold scrap carbonate solution such as sodium carbonate, which is used for the production of basic copper carbonate, which is used as a raw material for copper preservatives, wood preservatives, and the like. The present invention relates to a manufacturing apparatus and a metal / recari metal carbonate solution purified by this method. Back-landscape technology ', ·

In general, basic copper carbonate (hereinafter referred to as “carbonic acid”) is widely used industrially as a raw material for copper oxide and wood preservatives, which are sources of copper plating materials. Copper carbonate is produced, for example, by reacting an aqueous solution of an inorganic copper salt such as cupric chloride with an aqueous solution of an alkali metal carbonate such as sodium carbonate.

When producing copper carbonate using alkali metal carbonate, for example, if calcium calcium compound is contained in the alkali metal carbonate as an impurity, the entire amount is mixed into the copper carbonate. I know that When copper carbonate mixed with these impurities is used as a copper plating material, the impurities are concentrated in the bath and deposited on the plating material, which adversely affects the finish of the plating. In addition, when used as a raw material for wood preservatives, wood preservatives ο these impurities will break out as insoluble residues during the manufacturing process, increasing the load on the product filtration process.

For example, industrial sodium carbonate powder contains more than 10 to 100 ppm by weight. Calcium and magnesium compounds are contained, and their contents vary depending on the production method and production lot. Therefore, there has been a demand for a technique for stably removing these impurities from Al-rich metal carbonate, which is a raw material for copper carbonate.

In response to such a request, Patent Document 1 discloses that nitrogen dioxide is blown into a sodium carbonate aqueous solution to precipitate sodium hydrogen carbonate or sesqui sodium carbonate as a solid, and the calcium ions of the aqueous solution are adsorbed on the solid surface to cause impurities. The technology to separate is described. However, this method is not economically efficient because some of the raw materials necessary for the production of copper carbonate and the like are consumed to separate impurities. Patent Literature 1 -2 1 0 3 3

The present invention has been made in view of the above circumstances, and it is therefore an object of the present invention to be able to remove sulfur compounds contained in an alkali metal salt easily and at a low cost without the need for repulsion. Possible alkaline metal carbonate: ^ Purification of the solution and providing alkali metal carbonate solution purified by this method bo

The method for purifying the Al-rich metal carbonate solution is to prepare an Alkali-Metal carbonate solution with an alkali metal carbonate concentration of 15O Process and.

When the Al strength metal carbonate solution is kept constant for a certain period of time, the precipitation impurities that precipitate the dissolved impurities in the Al force metal carbonate solution and the Al force metal carbonate solution And a solid-liquid separation step of solid-liquid separation.

The method may be a dilute step in which the precipitated impurities are separated and the solution is made of water with a predetermined concentration of alkaline carbonate solution. Alternatively, in the precipitation process, impurities are deposited and force, alkali: dilute the solution with water (dilution process), and then separate the precipitated impurities and alkali '. This solution is solid-liquid separated (solid-liquid separation process) Configure it.

[The concentration of Al-rich metal carbonate solution in the process is 60 ° / against the strength of Al-rich metal carbonate. As described above, it is preferable that the alkali carbonate in an amount less than the saturation solubility has a high concentration. This refining method is also suitable for the case of using a single-capacity sodium carbonate or carbonated lithium! : Yes.

According to the method for purifying an anolelic metal carbonate solution, the force / resium compound, which is an impurity dissolved in the anolelic metal carbonate, can be precipitated and separated. For this reason, the alkali metal carbonate in the aqueous solution is made into a solid i: Conventionally, impurities such as calcium ions are deposited on the deposited solid. Unlike the above method, there is no loss of alkali metal carbonate to be a product, so it is possible to purify the alkali metal carbonate solution economically and efficiently. Also, in this purification method, impurities can be precipitated simply by keeping the temperature of the alkaline metal carbonate solution for a certain period of time while controlling the temperature of the alkali metal carbonate solution. There is no need for special processes such as adapting. For this reason, the apparatus configuration and the operation method thereof are simplified to carry out the method, and it becomes possible to purify the alkali metal carbonate solution easily and at low cost. Brief Description of Drawings

囱 1 is a flow chart illustrating the method for purifying an aqueous sodium carbonate solution according to the embodiment. .

FIG. 2 is a configuration diagram showing an example of a purification apparatus for an aqueous sodium carbonate solution according to an embodiment. '.

FIG. 3 is a characteristic diagram showing the results of an experiment conducted to confirm the effect of the present invention. FIG. 4 is a characteristic diagram showing the results of experiments conducted to confirm the effects of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

As an example of the embodiment of the method for purifying the Al 'metal carbonate solution according to the present invention, a method for purifying sodium carbonate containing calcium as an impurity will be described with reference to FIG. 1'. Figure 1 is a flow chart for 5 treatments that purify sodium carbonate. In this embodiment, for example, sodium carbonate powder (soda ash) generally sold for industrial use is used as a raw material, and this is subjected to a purification treatment, for example, a predetermined concentration used for producing copper carbonate to be a copper plating material. The case of refining the sodium carbonate aqueous solution will be explained. The sodium carbonate powder used for collection contains impurities such as calcium carbonate in the production process, for example, about several H "to 100 ppm by weight. This is a treatment for removing high-purity sodium carbonate containing no impurities or low impurities. -First, as shown in Figure 1, the impurity calcium, for example, 2 10 ppm by weight For example, sodium carbonate powder for industrial use is dissolved in water heated to 30 ° C., for example, so that the sodium carbonate concentration is 30 wt. /. Prepare an aqueous solution of sodium acid (. Step S 1 (Preparation process)). At this time, the concentration of force / resium is determined by the sodium carbonate powder used as a raw material and the concentration of this aqueous solution, and in this embodiment is 63 fc p ρ .πι. Usually, sodium carbonate aqueous solution t used for the production of copper carbonate, and the reaction between sodium carbonate and cupric chloride during the production of copper carbonate are promoted in a stable manner. In order to obtain copper carbonate with a diameter distribution, it is shipped as a k solution with a concentration of, for example, about 10% by weight. On the other hand, this product is prepared in a high-concentration aqueous solution so that it is about 3 times the product i; 10 g of water at 30 ° C [saturated solubility is about 31.2% by weight for thorium carbonate, and about 0.7% for force (for example, calcium carbonate). /. Therefore, none of the substances contained in the prepared aqueous solution of trimethyl carbonate is in a harmonized state.

Next, preparation □: The sodium carbonate aqueous solution obtained in the above step is kept, for example, for one day while being heated to the same temperature as at the time of preparation. ¾, and a calcium compound solid is precipitated from this aqueous solution (step S 2 ( Precipitation step).). In this step, calcium in the prepared sodium carbonate aqueous solution can be precipitated as a solid regardless of whether it is not saturated. This is because, by increasing the concentration of carbonate ions and other impurities derived from sodium carbonate, the equilibrium state of the aqueous solution can be maintained in the direction of the formation of lucium compounds such as lucium carbonate. It is thought that it is -On the other hand, 10 weight is conventionally shipped as a product. Even if an aqueous sodium carbonate solution of about ₀ is prepared and retained, the reaction rate of the reaction for precipitating the calcium compound is slow, so a sufficient amount cannot be treated, and it can be applied to industrial processes. It was difficult. As a result of diligent research on such problems, it has been found that calcium carbonate can be precipitated in a relatively short time by dissolving sodium carbonate powder as a raw material of the inventor at a high concentration in water. In general, the reaction rate of a substance dissolved in a solution is faster than the concentration of the reacting substance. Therefore, by adjusting the aqueous sodium carbonate solution to a high concentration, for example, the concentration of carbonate ions and calcium dissolved in the aqueous solution also increases. It is considered possible to increase the reaction rate of the reaction for precipitating the ruthenium compound. ,

In addition, since the equilibrium relationship of whether or not calcium dissolved in an aqueous sodium carbonate solution is precipitated is determined by the concentrations of carbonate ions, calcium, etc. in the aqueous solution, the higher the concentration power S, the higher the calcium compound. It is thought that the amount of precipitation can be increased. In other words, it can be said that the higher the aqueous sodium carbonate solution is prepared, the more calcium is precipitated as calcium compounds, and the higher the calcium removal rate is. .

Here, the amount of calcium contained in the industrial sodium carbonate powder varies depending on the manufacturer and the production outlet, so it cannot be controlled in each process of purifying sodium carbonate1, . For this reason, in order to prepare an aqueous sodium carbonate solution with a high concentration of calcium, a large amount of sodium carbonate powder that can be dissolved in water and the concentration of the strength sodium dissolved together is also high. Preparation to be needed. However, as already mentioned, the solubility of sodium carbonate powder in soot at 30 ° C is about 31.2% by weight. If this is done, the product sodium carbonate will precipitate together with the impurities, leading to an economical mouth. -Therefore, in this embodiment, the amount of sodium carbonate dissolved does not reach the saturation level so that sodium carbonate strength S does not precipitate and the calcium concentration can be increased as much as possible. It is manufactured by the f office so that the concentration of sodium carbonate solution is as high as possible. For this reason, a saturated ^ concentration of the solution to about 3 1. Less than 2 wt ^_0/0 of carbonate Natoriumu in preparation step, 6 0% or more solubility in saturated solubility (about 1 8.7 by weight% As described above, the concentration of the sodium carbonate aqueous solution is adjusted to 30% by weight, for example. If the sodium carbonate aqueous solution prepared in this way is kept for one day, for example, the canorescium concentration can be reduced from several tens of ppm to about 10 ppm by weight.

In the aqueous sodium carbonate solution in which calcium is precipitated as a solid in the precipitation step, the calcium compound is removed by, for example, a filter (step S 3 (solid-liquid separation step)). In this solid-liquid separation process, it is mixed in the sodium carbonate aqueous solution. 'Calcium compounds will be separated. '

The aqueous sodium carbonate solution from which the precipitated impurities have been separated is used, for example, 10

'' Diluted to a concentration of% by weight with ion exchange not containing calcium

(Step S4 (dilution process).). The concentration of calcium in the diluted aqueous sodium carbonate solution decreases to about 2 to 3 weight pm.

Next, the diluted sodium carbonate 'water' solution is introduced into an adsorption tower packed with ion exchange resin and brought into contact with the ion exchange resin, and is not precipitated in the precipitation step but remains dissolved in the aqueous solution. Ions are removed by adsorption (step S5, (adsorption process)). The ion exchange resin used in the adsorption process is a type that selectively adsorbs calcium ions and magnesium ions compared to sodium ions, such as Amberlite (registered trademark) I 'RC 7 48. Good. By contacting with an ion exchange resin, for example, the concentration of calcium ion dissolved in an aqueous sodium carbonate solution can be reduced to 0.1 weight p p'm or less.

• Next, we will explain the smoked S, which purifies sodium acid based on the above flow.

• Explain. Figure 2 shows an example of the configuration of this refiner. This equipment is used to dissolve powdered sodium carbonate in water to prepare a high-concentration sodium carbonate aqueous solution-'disintegration tank 1.0, and to precipitate calcium compounds as solids from sodium carbonate aqueous solution. Retention tank 20, 'Filter 30 for separating and removing precipitated calcium compounds, Dilution tank 40 for diluting sodium carbonate solution from which calcium compounds have been separated, After dilution It consists of a resin tower 50 and a column for adsorbing and removing the potassium dissolved in the sodium carbonate aqueous solution.

More specifically, the molten metal tank 10 is connected to a raw water supply tank (not shown) via a raw water supply pipe 11 a provided with a raw water supply valve 11. The raw water supply 1 1 serves to continuously supply a predetermined amount of raw water to the dissolution tank; I 0. In addition, a hopper 9 storing sodium carbonate powder is installed above the dissolution tank 10. The dissolving tank 10 is provided with a t-quantifier (not shown) and serves as a supply means for supplying a predetermined amount of sodium carbonate powder to the dissolving tank 10 continuously or intermittently.

Furthermore, the melting plant 10 is supplied with a mixer 12 for stirring the sodium carbonate J solution in the dissolution tank 10 and a steam supply pipe for supplying steam for heating the sodium carbonate aqueous solution B. 1 3 a is installed. In addition, bottom piping 14 a is attached to the bottom of dissolution tank 10 and the bottom pump 14 is used to dissolve the sodium carbonate aqueous solution.

It has become possible to extract from 1 0. The bottom pipe 4 a is provided with a thermometer (not shown), and this thermometer is connected to the temperature controller 15. The temperature controller 15 is a steam supply valve 1 3

Connected to 3. Temperature controller: L 5 is the temperature of the solution in the dissolution tank 10 by opening and closing the steam supply valve 13 according to the temperature of the sodium carbonate aqueous solution flowing through the bottom pipe 14 a and increasing or decreasing the amount of steam supplied It has a role to control so that is constant. . "

'' Bottom piping 1 4 a is branched into return piping 1 6 and extraction piping 1 7; expanded piping 1 6 is bottom piping 1 4 a part of sodium carbonate aqueous solution flowing through 4 a It plays the role of returning to 0. Further, the extraction pipe 17 is connected to the retention tank 20, and serves to extract the sodium carbonate ice solution that has not been returned to the dissolution tank 10 to the retention tank 20. ',

Next, details of the retention tank 20 will be described. The retention tank 20 is a vessel having a capacity such that the retention time of the sodium carbonate aqueous solution received from the dissolution tank 10 is, for example, 6 hours, and is dissolved in this solution. It acts as a precipitation tank that deposits sodium carbonate as a solid. The retention tank 20 is provided with a mixer 21 and a heater 22 and so that the sodium carbonate aqueous solution in the retention tank 20 can be uniformly added. The heater 22 is connected to a thermometer (not shown) installed in the stay 樓 20 via a temperature controller (not shown).

22 By adjusting the output of 2, the temperature of the aqueous sodium carbonate solution in the residence tank 20 can be kept constant.

Potom pipe 2 3 a is attached to the bottom of the retention tank 20, so that the sodium carbonate aqueous solution on which the force-lucium compound is precipitated can be extracted from the retention tank 20 by the bottom pump 23. . For example, the filter on the discharge side of the bottom pop 2 3 has a filter, such as a filter cartridge.

3 0 is inserted. The filter 30 serves as a solid-liquid separation means for filtering and separating the calcium compound from the aqueous sodium carbonate solution extracted from the residence tank 20. Play a role. The solid-liquid separation means is not limited to the case where the exemplified filter 30 is used. For example, the precipitation tank may use a liquid cyclone or the like. The bottom pipe 2 3 a is branched at the outlet side of the filter 30 into a return pipe 2 4 and an extraction arrangement 2 5, and the return pipe 2 4 is an aqueous solution of sodium carbonate that has been overlooked by the filter 30. Part of the stagnation tank 20 serves to return to the reservoir tank 20, and the extraction pipe 25 serves to extract the remaining aqueous solution to the dilution tank 40. ''

Next, details of the diluted sodium carbonate 40 will be described. The dilution tank 40 receives the sodium carbonate aqueous solution from which the calcium compound has been filtered by the filter 30 from the distillation tank 30 and dilutes it with water to a predetermined concentration, for example, to the degree of shipping as a product. It ’s a vessel. The dilution tank 40 is connected to a dilution water supply tank (not shown) via a dilution water supply pipe 41a provided with a dilution water supply valve 41. The dilution water supply valve 41 serves to continuously supply dilution water such as ion exchange water that does not eat impurities such as calcium to the dilution tank 40. The dilution water supply valve 4 '1 is connected to a non-illustrated line analyzer via a flow rate controller (not shown), for example, and according to the result of measuring the concentration of the diluted sodium carbonate aqueous solution with an online analyzer. The supply amount of dilution water can be increased or decreased. In the diluting tank 40, a mixer 1.42 is installed in the following manner, and plays a role of stirring and mixing the aqueous solution of sodium spreading acid and the liquid with the diluting water. ''

A bottom pipe 4 3 a is attached to the bottom of the dilution tank 4◦, so that the aqueous sodium carbonate solution diluted to a predetermined concentration can be extracted from the dilution tank 40 force by the bottom pump 43. RU The bottom pipe 4 3 a branches into the drain pipe 4 4 and the extraction pipe 4 5, and the return pipe 4 4 has the effect of returning one sound 1 of the diluted aqueous sodium carbonate solution to the dilution tank 4 0. ij is fulfilled, and the extraction pipe 45 serves to extract the remaining liquid J solution into the resin tower 50.

The resin tower 50 functions as an adsorption tower that adsorbs and removes calcium dissolved in the aqueous sodium carbonate solution without being deposited in the residence tank 20. Resin tower 5 Ο ί, for example, a packed tower filled with spherical ion exchange resin. The resin tower 50 has such a capacity that a sufficient replacement time can be secured for reducing the calcium dissolved in the sodium carbonate ice solution to the product concentration. The bottom of the resin tower 50 Extraction pipe 5 1 is connected. · Not shown! /, Plays the role of extracting purified sodium carbonate aqueous solution into the product duck. ,

Next, the operation according to the present embodiment will be described. The sodium carbonate powder supplied from the hopper 9 at a predetermined supply speed is mixed with a predetermined amount of raw water supplied from the raw water ^ 1 combined pipe 1 1. For example, it is prepared into a sodium carbonate aqueous solution having a concentration (30% by weight) about 3 times that of the product (corresponding to step S1 in FIG. 1). At this time, the concentration of calcium dissolved in the sodium carbonate aqueous solution is, for example, about several tens of weight p IP m ”. Also, the sodium carbonate aqueous solution is“ steam supply pipe 1 3 ”—a It is heated to, for example, S 0 ° C. in contact with the steam supplied from .The smoked sodium carbonate aqueous solution is sent to the residence tank 20.

The sodium carbonate aqueous solution nuclei fed to the residence tank 20 are held for about 6 hours, which is the average stagnation time, while being stirred by the mixer 21 and heated by the heater 22. During this holding period, calcium compounds as impurities are precipitated from the aqueous sodium carbonate solution, and the concentration of dissolved calcium drops to around 10 'ppm by weight (Fig. 1). Corresponds to step S2). 'The sodium carbonate aqueous solution in which the calcium and sulfur compounds are precipitated is passed through the filter 30 and the calcium compound is separated and sent to the dilution tank 40 (same as Steza. S 3). )

Carbonated Natoriumu water solution that is fed to the dilution tank 4 0 is mixed with ShakuHisashi supplied from 4 1 a dilution water supply pipe while being撐拌a mixer ⁴ 2, the concentration to be shipped as a product (e.g., 1 0 is diluted to carbonate isocyanatomethyl ¹ click um aqueous solution wt%) (primate to those in step S 4 in FIG. 1). At this time, for example, about 2 to 3 ppm by weight of calcium is dissolved in the aqueous solution. In this state, the sodium carbonate aqueous solution sent to the resin tower 50 is sent to the resin tower 50. In contact with the ion exchange resin in the tower, calcium ions dissolved in the aqueous solution are selectively sucked and removed (corresponding to step S5 in Fig. 1). Through each of the above processes, the aqueous sodium carbonate solution is refined to a state where the dissolved calcium concentration is, for example, less than 0.1 wt. P, and is sent to the product tank. According to the present embodiment described above, calcium can be precipitated from this aqueous solution as a solid by simply holding the sodium carbonate aqueous solution at a high concentration made of JS. Since impurities can be released as solids without any special reaction operation with other substances, it is possible to purify an aqueous sodium carbonate solution with a simple apparatus configuration. As a result, the apparatus configuration of the sodium carbonate refining apparatus is simplified, the operation details are simplified, and the operation cost of the equipment can be reduced. .

In addition, by increasing the concentration of the sodium carbonate aqueous solution to a high concentration of 15% by weight | ^, the rate of precipitation of impurities increases, so that the carbon dioxide that can be purified in time is lower than when the concentration of the aqueous solution is low. The amount of sodium aqueous solution can be increased. Further, the concentration of sodium carbonate and aqueous solution can be increased to improve the percentage of impurities that can be removed. At this time, by setting the concentration of the sodium carbonate aqueous solution to a concentration at which sodium carbonate is dissolved at a concentration of 6.0% or more with respect to the saturated solubility of sodium spreading acid and less than the saturation solubility, Impurities can be deposited at the highest speed, and the most efficient conditions can be achieved so that the product, sodium carbonate, co-deposits with impurities and is not removed in the solid-liquid separation process. .

Further, after the precipitated impurities are separated, the concentration of the impurities in the aqueous solution is removed by adsorbing and removing the force / recovery Λ dissolved in the aqueous solution of sodium carbonate in contact with ion exchange grease. Can be further reduced. As a result, the sodium carbonate brine solution can be purified to a high dullness such that the concentration of impurities is, for example, less than or equal to 0.1 weight ppm.

The alkali metal carbonate that can be purified by the present invention is not limited to sodium carbonate exemplified in the embodiment. For example, the present invention can also be applied to the purification of potassium carbonate used as a raw material for potassium salts and the like. Further, even when the soda ash used as the raw cattle contains impurities made of magnesium, the impurities can be removed from the sodium carbonate aqueous solution by contacting with ion exchange resin.

In addition, the method of preparing a high-concentration sodium carbonate aqueous solution in the preparation step is not limited to that exemplified in the embodiment. For example, low-concentration sodium carbonate containing impurities It is also possible to prepare a high concentration by purchasing aqueous solution of sodium chloride and evaporating the water to concentrate the aqueous solution.

Still, in the embodiment, after diluting the aqueous solution of sodium carbonate from which the precipitated calcium compound is separated, the calcium dissolved in the aqueous solution is removed by adsorption in the adsorption step. However, the presence or absence of the dilution step and the adsorption step, and the order of these steps: II are not limited to those illustrated. For example, after separating the precipitated impurities in solid-liquid separation II :, the aqueous sodium carbonate solution may be shipped as it is, or it may be shipped after being diluted in the dilution step. Immediately after the solid coating separation process, the impurities dissolved in the deposition process are adsorbed and removed, and the sodium carbonate aqueous solution may be loaded as it is, or a dilution process may be provided after the P deposition process. Good.

In addition to this, the order of the solid-liquid separation step and the dilution step is changed, and impurities are precipitated. After the alkaline metal carbonate solution is diluted with water, the precipitated impurities are separated into the solid-liquid separation step ( It may be configured so that it can be separated, and after this, it may be further removed by adsorbing and removing the undissolved impurities in the process of “adsorption:!:”. Because it is.

(Example) '· - . .

(Experiment 1) · '-'

The effect of the concentration of aqueous sodium carbonate solution on the reaction of precipitating a ^7- resium compound was evaluated. · ■■ '

(Example 1-1)

Sodium carbonate powder (industrial soda ash: calcium compound content 21 1 ppm by weight ppm) is dissolved in ion-exchanged water to prepare a sodium carbonate k solution with a concentration of 30% by weight. These sodium oxalate aqueous solutions were kept at room temperature for 1 hour with stirring, and the calcium concentration in the mother liquor obtained by suction filtration of the total amount was measured. The sodium carbonate aqueous solution after suction filtration was kept at room temperature without stirring, and the calcium concentration in the mother liquor obtained by suction filtration of the whole amount again after a total of one day was measured. Next, the aqueous sodium carbonate solution after suction filtration is kept at room temperature without stirring, and after a total of four days, the calcium concentration in the mother liquor obtained by suction filtration is measured. Also, visually check the sodium carbonate soot solution at a predetermined timing. Observed. For filtration, a glass filter having a retained particle size of 0.5 μπι was used. The results of the experiment are shown in (Table 1). 'Also, the sodium carbonate solution obtained as a result of the experiment is shipped, for example, as a product. (Table 2) shows the converted value of calcium concentration when diluted in an aqueous solution of ₀ . Tables 1 and 2 also show the results of Examples: L-2 to 1 to 1 and Comparative Example 1 to 1.

(table 1) . ' ' .

Changes in calcium attack (weight p pm) with time due to differences in concentration of sodium carbonate aqueous solution,

(Table 2)

The value shown in Table 1 is converted to a 10% by weight sodium carbonate solution (force concentration: weight _P pm)

Examples Examples. Examples. Comparative Examples

1— 1 1-2 1-3 1 -1 sodium carbonate

30 wt% 20 wt% 1 5 weight ^_0/0 1 0 wt ° Concentration

Initial concentration 21 2 1 21 2 1

After 1 hour 9 1 2 1 3 14

After 1 day 3 6 8 1 2

After the day, 3 6 9 1 3 (Example 1 1-2, 1-3)

The concentration of the sodium carbonate aqueous solution is 20, 15 weights, respectively. /. The experiment was conducted under the same conditions as in Example 1-1. .

(Comparative Example 1)

The experiment was performed under the same conditions as in Example 1-11, except that the concentration of the aqueous sodium carbonate solution was 10% by weight. .

(Experiment i considerations) ·,

According to the results of visual observation during the trial, after preparing an aqueous sodium carbonate solution and passing for 1 hour, each of the solutions in Example 1-1-1 to 1-3-1 and Comparative Example 1-11-1 White turbidity was seen. In addition, the higher the concentration of the aqueous sodium carbonate solution, the greater the degree of turbidity. When 1 hour passed, suction filtration of each sodium carbonate aqueous solution was performed with ^ ;, and a clear aqueous solution without turbidity was obtained. Next, when the observation was performed at Nichiji point where 1 has elapsed since the holding was opened, the concentration of the sodium carbonate aqueous solution was 15% by weight (Example 1 1 3), 20% by weight (Example 1 1 2 ), An aqueous solution of 30% by weight (Example: L 1 1 ') was slightly cloudy and a white precipitate was observed. On the other hand, such turbidity was not observed in an aqueous solution of 10 ′ weight (Comparative Example 1-L). When these sodium carbonate aqueous solutions were suctioned again, a clear aqueous solution without turbidity was obtained. When observation was made after 4 days had passed since the start of the retention, no white precipitate was observed in the aqueous solution of tricarbonate with a different concentration. ·

Fig. 3 (a-) and Fig. 3 (-¾) show the results of plotting the time-dependent changes in calcium concentration shown in (Table 1) and (Table 2). The horizontal axis of Fig. 3 (a) and Fig. 3 (b) shows the elapsed time, and the vertical axis shows the calcium concentration in the sodium carbonate aqueous solution. The result when the concentration of the aqueous sodium carbonate solution is 30% by weight is plotted with a pad (X), and the trend line is shown as a solid line. Similarly, the results of 20% by weight are indicated by a triangle,,, and a dashed-dotted trend line, and 15% by weight is indicated by a square (騙) brot and a two-dot chained slope. Furthermore, the results of 10% by weight are indicated by the rhombus (◊) broth and the broken trend line.

According to the results of the experiment shown in Fig. 3 (a), Example 1-1 to Example 1-13, In any one of Examples 1 and 1, the concentration of chanoleum in the aqueous sodium carbonate solution is monotonously decreasing. The decrease in calcium concentration is thought to be the result of consumption of calcium in the sodium carbonate aqueous solution due to the precipitation of calcium compounds. In addition, the elapsed time from the start of retention for any result is 13 3 temple power, the rate of decrease in calcium concentration during the period up to 1 day is fast ', and the rate of decrease as the elapsed time increases Slow down, and the calcium concentration has hardly changed during the period of 1 to 4 days. This is thought to be because the calcium concentration in the aqueous sodium carbonate solution changed to a flat state due to the precipitation of the calcium compound. "-

'' Hold the aqueous sodium carbonate solution and measure the rate of calcium reduction in the solubilized solution from 1 hour to L days. Example 1 1 1 to Example 1 1 3, Comparative Example 1-1 Compared to the results, the higher the concentration of sodium carbonate aqueous solution, the faster the canoresium reduction rate. This is thought to be because the concentration of carbonate ions is higher in the aqueous sodium carbonate solution prepared at a higher concentration, and as a result, the rate at which calcium compounds precipitate is increased, resulting in a faster rate of decrease in calcicum. .

― Consider the graph shown in Fig. 3 (b). Fig. 3 (b) shows the force concentration (converted value) when the experimental results obtained in each cold application and comparative example were diluted with 10% by weight sodium carbonate-water solution. In the 10% by weight converted value, the initial concentration of calcium in each of the examples and comparative examples is 21 weight: consistent with ppm, but the calcium in each aqueous sodium carbonate solution as the retention time elapses. There is a difference in concentration. That is, in the hot water (Example 1-1-1) in which the concentration of the aqueous sodium carbonate solution was 30% by weight, the strength concentration after conversion to 10% by holding the aqueous solution for 1 day was 3 ppm by weight. And about 87% of the force shim is removed from the initial concentration. In contrast, a sodium carbonate aqueous solution having a concentration of 20% by weight is approximately 71% (Example 1 1-2) and 15% by weight. /. In this aqueous solution, the rate of calcium removal decreases as the concentration of the prepared aqueous solution decreases to about 5 7% (Example 1 13). And 10 weight. /. Only 33% calcium can be removed with sodium carbonate solution (Comparative 1-11). In addition, when focusing on calcium concentration, the sodium carbonate concentration is 30%, 20%, and 15% by weight. In the case of Example 1 1 to Example 1 1 and 3), the concentration of chanoresmu in the aqueous solution after dilution can be reduced to 10 ppm by weight or less with a retention time of 1 day or less. In the case where the concentration of the J solution was 10% by weight, the canoresium concentration could not be reduced to 10 ppm by weight or less even after 1 day. If the concentration of the diluted liquid can be reduced to 10 ppm by weight or less within one day, it is considered possible to apply the smoke production method according to the present invention to an industrial process.

(Experiment 2)

We evaluated the changes in the concentration of calcichem in the aqueous sodium tricarbonate solution during a relatively short period of time.

(Example 2-1)

Example 1 1-1 Prepare and hold an aqueous sodium carbonate solution (sodium carbonate! 30 wt.% »%) Under the same conditions as in 1. Prepare an aqueous solution sampled after 1 hour, 2 hours, 4 hours, and 6 hours. The calcium concentration in the mother liquor obtained by suction filtration was measured. In this example, in order to bring it closer to the state in the residence tank 20 shown in FIG. 2, place the beaker prepared with the aqueous sodium carbonate solution in the thermostatic bath and bring the aqueous solution to 30 ° C. The temperature of the soot and the point of stirring with the stirrer chip continuously while holding the aqueous solution were held at room temperature and stirred for the first '1 hour. It is different. In addition, a sample of the sodium carbonate aqueous solution in the beaker was sampled and subjected to suction filtration, and the result was analyzed, so that each time analysis was performed, the entire amount of the aqueous solution was suctioned and filtered, and then analyzed. The conditions are different from those of Example 1-1. In other words, it differs from Example 1-11, in that the precipitated ruthenium compound is stored in the aqueous solution without being removed by filtration. For other experimental conditions 1

The explanation is omitted because it is the same as 1. The results of the experiment are shown in (Table 3). Note that (Table 3), Comparative Example 2 1 The results及Pi, are also shown results of 1 one 1 for reference _D

(Table 3)

Calcium concentration change '' Examples Examples. Comparative Examples

2—1 1-1 2-1

Initial concentration 6 3 6 3 1 0

After 1 hour 2 9 2 7 5

After 2 hours 1 5 ― 5

After 4 hours 8 —-5

6 hours later 6 .. ― 6

After 1 day 1 8 1

After 4 days 1.

(Comparative Example 2-1)

The experiment was performed under the same conditions as in Example 2-1, except that sodium carbonate (calcium compound content 33 wt. Pm) having a low calcium compound content in the powder was used. '' '

(Consideration of Experiment 2) '

Figure 4 'shows a rough plot of the time-dependent changes in force / resium concentration shown in (Table 3). The horizontal axis shows the time elapsed, and the vertical axis shows the canoresium concentration in the aqueous sodium carbonate solution. The result of Example 2-1 is plotted with a square (mouth), and the result of (ratio reduction example 2-1) is plotted with a triangle (J). Plotted with a cross (X), and the solid and solid lines indicate the inclination of each concentration change.

As shown in the graph in Fig. 4, in any case of Example 2-1 and Comparative Example 2-1; even if it is kept, the calcium concentration in the aqueous solution decreases monotonously by maintaining the aqueous sodium carbonate solution. ing. In addition, the change in the rate of calcium decrease is the same as in Experiment 1 where the decrease rate decreases faster as the retention time increases. In addition, when Example 2-1 and Comparative Example 2-1 are compared, even when the concentration of the sodium carbonate aqueous solution is the same, the initial concentration of calcium at the time of preparation of the aqueous solution ¾Γ is different. The higher the concentration, the rate of calcium reduction and its It can be seen that the removal harm ij is high. In Example 2-1 and Example 1-1, there is no significant difference in the change in the concentration of calcium in the aqueous sodium carbonate solution.

(Experiment 3).

An aqueous solution of sodium carbonate is brought into contact with an ion exchange resin, and an adsorption and removal experiment of canore- mium or magnesium contained in the aqueous solution is conducted 1.

(experimental method) : . · .

Power — The ram is packed with 50 mL of ion exchange resin (Amberlite I RC748) and the column is 10% by weight sodium carbonate in water-(cal, num content 1. 3 wt p pm, magnesium content 0.5 wt p pm). A total of 9 Q Oml (equivalent to 18 times the amount of resin) sodium carbonate aqueous solution is passed through, and every 15 O m 1 (equivalent to 3 times the amount of resin) Ii) Sampling the aqueous solution passed through to determine the strength concentration and the concentration concentration. The direction of flow was downward flow, and the listening speed was 3 h r-1. Kara is also equipped with a jacket, and hot water at 60 ° C was circulated through this jacket. The results of the trial are shown in (Table 4). ''.

(Table 4)-Concentration of impurities in sodium carbonate ice lip liquid in contact with ION exchange resin Treatment volume Calcium concentration Magnesium concentration

[Direct P p m] and amount P n]

Original solution 1. 3 0.5

0 to 3 0. 1 or less .0. 1 or less "F

3 to 6 0. 1 or less 0. 1 or less

6-9 0. 1 or less 0. 1 or less

9 to 1 2 0. 1 or less 0. 1 or less

1 2 to 1 5 0. 1 or less 0. 1 or less

1 5 ~: 1 8 0. 1 or less 0. 1 or less (Consideration of Experiment 3) '

According to the results shown in (Table), for either calcium or magnesium, during the period 1¾ when sodium carbonate aqueous solution equivalent to 18 times the amount of resin was passed through. The concentration of these impurities can be stably reduced to 0.1 ppm or less. From this result, water obtained by maintaining the aqueous solution of sodium carbonate and dispersing the precipitated impurities. When the solution is further refined, it is highly purified by contacting it with ION It can be seen that ζ> is obtained.

Claims

' The scope of the claims ·

1. Concerning alkali metal carbonates containing impurities composed of calcium compounds, the concentration of alkali metal carbonate is 15% by weight. A preparation step for preparing the above alkaline metal carbonate solution;

Holding the Al-rich metal carbonate solution for a certain period of time so that the Al-rich metal carbonate does not precipitate; an analysis step for precipitating the dullness dissolved in the Al-rich metal carbonate solution;

A liquid-liquid separation step for solid-liquid separation of the precipitated waste and the alkali metal carbonate solution, and a method for purifying the alkali metal carbonate solution, comprising:

2. Diluting the precipitated impurities by diluting with 7 water metal carbonate solution with water to produce a predetermined concentration of alkaline metal carbonate: ^ solution. The method for purifying an Al force Li ^^ carbonate solution according to claim 1. '

3. The concentration of alkali metal carbonate is 15 times * by adding to the alkali metal carbonate containing impurities consisting of ruthenium compounds. / Prepare _zero or more Al metal carbonate solution preparation process and '

The tfcl step for depositing impurities dissolved in the alkali metal carbonate solution by holding the alkali metal carbonate solution for a certain period of time so that the alkali metal carbonate does not precipitate, and, '

A dilution step of diluting the alkali metal carbonate solution in which impurities are deposited with water to produce a predetermined i degree alkali metal carbonate solution;

A solid-solid separation step of solid-liquid separating the precipitated impurities and the alkaline metal carbonate solution, and a method for purifying the alkaline metal carbonate solution.

4. The method further comprises an adsorption step in which the impurity metal carbonate solution from which the deposited impurities have been separated is brought into contact with the ion exchange resin, and the impurities dissolved in the alkali metal carbonate solution are adsorbed and removed. The method for purifying an alkali gold carbonate solution according to claim 1 or 3.

5. The concentration of the alkaline metal carbonate solution in the preparation step is 60% or more with respect to the saturated solubility of the alkaline carbonate metal carbonate, and the alkali metal acid salt in an amount less than the saturated solubility is dissolved. The concentration / concentration of claim 1 or 3, wherein Purification method for lithium metal carbonate solution.

6. The alkali metal carbonate solution according to claim IL or 3, wherein the alkali metal carbonate is sodium carbonate or potassium carbonate.

7. The alkali metal carbonate solution purified by the method of purifying the solution of the alkaline metal carbonate: ^: solution described in any one of claims 1 to 6.

8. Supply means for supplying an alkaline metal carbonate powder containing impurities comprising a calcium compound;

Dissolve the alkaline gold dust carbonate powder supplied from this supply means in water to prepare an alkaline metal carbonate solution with a concentration of 15% by weight or more of alkaline metal carbonate. A tank, and a puddler deposit that holds the alkaline metal carbonate solution to prevent precipitation of impurities dissolved in the alkaline metal carbonate solution so that the alkaline metal carbonate solution does not precipitate. Tank and '-

_; Purification device of an alkali metal carbonate solution, characterized in that it and a solid-liquid separation hands stage for solid-liquid separating the precipitated impurities and Arukari metal carbonate solution.

9. A diluting tank ¾r is further provided for producing an alkaline metal carbonate solution having a predetermined concentration by diluting the alkaline metal carbonate solution from which the precipitated impurities have been separated with water. The apparatus for purifying an alkaline metal carbonate solution according to claim 8.

1 0.. Force: a supply means for supplying an alkali metal salt powder containing impurities,

Dissolving tank for preparing alkali metal carbonate hot metal having a concentration of 15% by weight or more of alkali metal carbonate by dissolving the molten metal carbonate powder supplied from this supply means in water. When,

A precipitation tank for holding the alkali metal carbonate solution so as to prevent precipitation of impurities dissolved in the alkali metal carbonate solution;

A diluting tank for diluting the alkaline metal carbonate solution with impurities deposited with water to produce an alkali metal carbonate solution having a predetermined concentration;

Solid-liquid separation hand for solid-liquid separation of the precipitated impurities and Al-rich metal carbonate solution And a step of purifying the alkali metal carbonate solution. '

1 1. Adsorption to remove the impurities dissolved in the alkaline metal carbonate solution by bringing the alkaline metal carbonate solution dispersed with the deposited impurities into contact with the ion-exchange resin. The apparatus for purifying an alkali metal carbonate solution according to claim S or 10, further comprising a tower.