JPS6036324A - Preparation of sodium carbonate - Google Patents

Abstract

PURPOSE:To obtain novel Na2CO3 extremely effective as a raw material component especially for a synthetic detergent, having very small apparent specific gravity, having high dissolution rate in water, by blending NaHCO3 with Na2CO3 and water in a given weight ratio to give a blend, uniforming and calcining the blend in specific temperature ranges, respectively. CONSTITUTION:A blend is prepared in such a way that it has a ratio of NaHCO3:Na2CO3(calculated as anhydrous state):H2O of 1:(0.2-1.5):(0.1-0.8), especially 1:(0.3-1.5):(0.1-0.5), by weight. The blend is then blended and uniformed at 40-105 deg.C, especially 50-100 deg.C, and calcined at a sufficiently high temperature (100-300 deg.C, preferably 150-220 deg.C). Consequently, NaHCO3 is decomposed and added water is dehydrated, to give the desired Na2CO3 having 0.4- 0.8 apparent specific gravity and <=40sec dissolution rate in water.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a novel method for producing sodium carbonate, which is extremely useful, particularly as a raw material component for synthetic detergents.

More specifically, the present invention relates to a method for producing sodium carbonate, which has good apparent specific gravity and water solubility, which are not found in anhydrous sodium carbonate commercially available so far.

Conventionally, anhydrous sodium carbonate has been produced by the so-called ammonia-soda method and ammonium chloride-soda method, that is, by reacting ammoniacal saturated salt water with carbon dioxide gas. It is manufactured by stressing at a temperature of 300°C.

The anhydrous sodium carbonate obtained by this method is industrially referred to as light ash, and generally has an apparent specific gravity of about 0.8 and an average particle size in the range of 90μ to 110μ. This light ash is generally used as a raw material for chemical industries such as food additives and dyes.

On the other hand, anhydrous sodium carbonate, which is used as a raw material for plate glass, pins, iron phase, detergents, and chemical industries, and is industrially referred to as m-ash, is produced by adding water to the light ash obtained by the above manufacturing method. Then, thorium carbonate-water salt (Na2co3
・lI20) and then drying this at a temperature such that the outlet temperature of the dryer is 110°C to 170°C. The mold skin obtained in this way generally has an apparent specific gravity of 1 or more and an average particle size of 200μ~
It is in the range of 400μ. It is also possible to obtain a similar reprint by carbonating caustic soda.

As is well known, sodium carbonate is an indispensable and effective raw material for synthetic detergents.

Until now, when using sodium carbonate as a raw material for synthetic detergents, whether using light ash or reprinted material, sodium carbonate is mixed with other detergent raw materials to form a slurry, and then the slurry is This method involves drying and granulating the detergent using a dryer at the same time. In this way, when using light ash and reprint, the main reason why it is necessary to make it into a slurry once and that sodium carbonate cannot be added after drying and granulation is that with light ash,
This is because the average particle diameter is small and the particle hardness is small, and in reprinting, the apparent specific gravity is large, so it is easy to separate from other synthetic detergent raw materials. In addition, light ash,
When using Juban by dissolving it in water, light ash has an extremely small particle size and tends to aggregate and form lumps when placed in water.On the other hand, Juban has a large apparent specific gravity, so it sinks to the bottom and the stirring intensity is low. It has disadvantages such as the need to raise the temperature to aid in dissolution.

In order to eliminate these drawbacks, the present invention eliminates the need to make a slurry during the manufacturing process of synthetic detergents, allows the addition of sodium carbonate even after drying and granulation, and allows the use of other detergent raw materials. The present invention was completed as a result of intensive research into a method for producing sodium carbonate, which allows the addition ratio of sodium carbonate to be freely adjusted and which is difficult to separate from other detergent raw materials.

The present invention provides an unprecedented method for producing sodium carbonate that has an extremely low apparent specific gravity and a high dissolution rate in water.

That is, the present invention has a weight ratio of sodium bicarbonate to carbonate of 1.
IJum (anhydrous equivalent): Water is 1. , :0.2~1.5:
After adjusting the ratio to be 0.1 to 0.8 and homogenizing the solid material at a temperature of 40°C to 105°C, it was heated to 100°C.
When heated at a temperature of ~300℃, the apparent specific gravity is 0.4~0,
This is a method for producing sulfur and lithium carbonate whose dissolution rate in water is 40 seconds or less.

In addition, the present invention can be carried out by appropriately mixing the assembled sodium carbonate and sodium carbonate or sodium carbonate hydrate obtained from the ammonia-soda method or the ammonium chloride-soda method as raw materials, but in that case, sodium bicarbonate :The weight ratio of sodium carbonate (anhydrous equivalent) is 1:
It is necessary to adjust it to 0.2-1.5. In addition, sodium bicarbonate, sodium carbonate hydrate, sodium carbonate anhydrous or sesquicarbonate obtained by carbonating a caustic soda solution or carbonating an electrolyte from a diaphragm brine electrolyzer or by treating natural soda ash. Sodium and the like can also be appropriately used as raw materials in the present invention.

What is important in the production method of the present invention is that the weight ratio of sodium bicarbonate:sodium carbonate (anhydrous equivalent):water is 1:0.2-1.5:Q, preferably 1:1-0.8, respectively. The mixture is adjusted to a ratio of 0.3 to 1.5: o, l - 0.5, and the prepared product is homogenized at a temperature of 40°C to 105°C, preferably 50°C to 100°C. That's true. Unless this condition is satisfied, the desired sodium carbonate cannot be obtained. For example, if the mixing temperature is less than 40°C, the particle hardness will be weakened, and if it exceeds 105°C, the apparent specific gravity will be different from the target value and will be undesirable. Further, although these reactions usually complete within 10 to 20 minutes after mixing, it is not desirable to use a mixer to stir the mixture too vigorously. In order to reduce the particle size of sodium carbonate, vigorous stirring must be carried out carefully and with appropriate stirring in consideration of crystal growth.

In addition, when the raw material contains thorium carbonate-water salt, it is desirable to control the amount of the aqueous solution used to a low level, but the total water content, that is, the sum of the water as crystal water and the water in the added aqueous solution. It is important that the amount is within the ranges mentioned above. Furthermore, if the amount of sulfur/lium carbonate hydrate used is too large, the hardness of the resulting crystals may decrease slightly. In the present invention, where sodium bicarbonate, sodium carbonate, and water are mixed as an example of a reaction operation, for example, 44 parts of sodium carbonate and 20 parts of water are added to 36 parts of sodium bicarbonate, and the mixture is thoroughly mixed for 20 minutes. Since 36 parts of sodium bicarbonate is about 20 parts in sodium carbonate equivalent, the mixing ratio of sodium bicarbonate and sodium carbonate is 1:1.2 by weight and 1:2 in terms of sodium carbonate equivalent ratio. The same reaction occurs if the ratio of sodium carbonate equivalents is between 2:1 and 1:3 between sodium bicarbonate and sodium carbonate. This mixed substance is heated to a sufficiently high temperature (100°C to 300°C, preferably 150°C to 220°C).
℃) to decompose the sodium bicarbonate and dehydrate the added water to obtain the desired sodium carbonate.

A further characteristic feature of the production method of the present invention is that the average particle diameter is 200μ to 600μ, although the reason for this has not been confirmed.
In addition to obtaining sodium carbonate with an extremely large particle size of μ, the resulting sodium carbonate has a small specific gravity of Q, 4 to eFF#-, and a powdering rate based on particle hardness. is less than 10%, and the dissolution rate in water is less than 40 seconds, which are unprecedented properties.

What is even more surprising is that the surface of the particles of the lithium carbonate obtained by the present invention is completely different from the light ash and weight obtained by the conventional method, and is in the form of aggregates of rod-shaped crystals. be.

In addition, the average particle diameter, apparent specific gravity, )'J) in the present invention
The conversion rate and dissolution rate are values calculated by the following measuring method, and the same applies to the Examples and Comparative Examples shown below.

(Average particle size) 100 g of the sample reduced with a bisparator was weighed on a balance (1 m
200g), transfer it to the top sieve of a stack of JTS standard sieves, which have a diameter equal to the particle size of the sample, cover the lid, and attach it to the 11-tap shaker Y11 machine. After shaking for a minute, the residue on the saucer and each sieve was weighed on a top balance (weighing 100 g).
Calculate the cumulative percentage of the nominal size μ of each sieve,
The nominal size μ of the sieve at which the concentration is 50 wt% or more is defined as the average particle size.

(Apparent ratio m) Weigh 50g of sample, the capacity is 100mj! Place it in a graduated cylinder (inner diameter approx. 2.7 cm), and beat it thoroughly on a thick rubber plate, being careful not to apply too much force, find the minimum volume Amβ, and calculate the apparent specific gravity using the following formula. do.

50 (g) Apparent specific gravity - □ (Powdery ratio A
For μ samples, take out only the sample above μ for 1.2 hours, weigh 50g of the mixed mixture for a long time, and weigh 1g.
Place in an intermediate saucer together with Fj and 151II in an aluminum mold with a diameter of 20 mm, and shake for 5 minutes with a shaker (do not use a sear at this time). Furthermore, the correspondence between the average grain size of the object to be measured is indicated by an asterisk.

(Dissolution rate) Pour 800m6 of pure water into a glass container with a diameter of 135n++n and a height of 180mm, and divide the container into a glass container with a thickness of 25mm and a length of 12mm.
A stirrer with four 8mm stirring blades was rotated at 550'rpm.200g of sample was added at once, and 2m7 was added every 5 seconds! The dissolved solution was sampled and titrated, and the concentration of dissolved sodium carbonate was 240 g//! Measure the time required to reach.

Examples will be shown below, but it goes without saying that the present invention is not limited to these examples.

Example 1 and Comparative Examples 1 to 2 Sodium bicarbonate and light ash obtained by the carbonation method of caustic soda solution were simultaneously fed into a mixer in the proportions shown in Table 1, and mixed and stirred using a spray nozzle. , 60°C warm water was added.

At this time, the temperature inside the mixer was adjusted by the opening degree of the damper at the top of the mixer, and the residence time was adjusted by the feed rate of the raw materials to the mixer.

For comparison, mixtures were made in the same manner as above, with the mixing ratios of the raw materials and operating conditions changed from those shown in Table 1, and these mixtures were heated in the same manner using a force machine at a temperature of 180°C. The average particle diameter, apparent specific gravity, pulverization rate, and dissolution rate of these sodium carbonates were measured. The results are shown in Table 1.

Example 2 In Example 1, in place of the sodium bicarbonate and light ash obtained by carbonating a caustic soda solution among the raw materials, bicarbonate obtained by carbonating an electrolyte from a diaphragm salt water electrolytic cell was used. Thorium carbonate was produced in the same manner as in Example 1 using thorium and sodium carbonate and under the mixer conditions shown in Table 1. The results are shown in Table 1.

Example 3 In Example 1, in place of the structured thorium carbonate obtained by the carbonation method of caustic soda solution among the raw materials, structured thorium carbonate and light ash obtained by the ammonia soda method were used, and Sodium carbonate was produced in the same manner as in Example 1 under the mixer conditions shown in Table 1. The results are shown in Table 1.

Example 4 Sodium bicarbonate, sodium carbonate hydrate, and anhydrous sodium carbonate obtained by carbonation of a 48% aqueous solution of caustic soda were mixed in a mixer, and while stirring, a hot aqueous solution (60°C) was added using a spray nozzle. Except for using 35kg,
Sodium carbonate was produced in the same manner as in Example 1 using a mixer column (not shown in Table 1). The results are shown in Table 1.

Reference Example For reference, Table 2 shows a comparison of the physical properties of the reprint and light ash obtained by the conventional ammonia-soda method and the sodium carbonate obtained by Example 3 of the method of the present invention.

Table 1 - Rhythm. ) As mentioned above, in Comparative Example 1, the ratio of light ash was increased in the mixing ratio of raw materials, but the average particle size at this time was only slightly deteriorated, but the apparent difference was Specific gravity and pulverization rate become very large. In Comparative Example 2, among the mixing ratios of raw materials,
It is made with a high proportion of sodium bicarbonate,
Although the apparent specific gravity becomes slightly higher, the average particle size deteriorates significantly. . On the other hand, the sodium carbonate produced by the method of the present invention obtained in Examples 1 to 4 exhibits extremely excellent physical properties in terms of average particle diameter, apparent specific gravity, powdering rate, and melting rate.

Table 2 Patent applicant: Toyo Soda Kogyo Co., Ltd.

Claims (1)

[Claims] The weight ratio of sodium bicarbonate:sodium carbonate (anhydrous equivalent):water was adjusted to a ratio of 1:0.2-1.5:o,t~0°8, and the prepared product was heated at 40'C. ~1
A method for producing +00 lium of the preparation after homogenization at a temperature of 0.05°C.