JPS6042231A - Manufacture of porous sodium carbonate having high surface hardness - Google Patents

Abstract

PURPOSE:To manufacture the titled sodium carbonate useful as a starting material for a synthetic detergent by calcining a mixture of sodium hydrogencarbonate with sodium carbonate and water, and adding water to the resulting granules to bring the surface layers of the granules into a hydration reaction. CONSTITUTION:1pt.wt. of sodium hydrogencarbonate is well kneaded with 0.2- 5pts. (expressed in terms of anhydride) sodium carbonate and water at 40-105 deg.C, and the kneaded material is calcined at 100-300 deg.C to decompose the sodium hydrogencarbonate and to remove the water. Water is sprayed on the resulting granules by an amount (weight) about 0.02-0.2 time the amount of sodium carbonate (expressed in terms of anhydride), and the surface layers of the granules are hardened by a hydration reaction to manufacture sodium carbonate having 0.4-0.9 apparent specific gravity and dissolving in water in <=40sec. An aqueous soln. having caking action such as an aqueous soln. of CMC or sodium silicate may be used in place of said water.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for producing porous sodium carbonate with a high surface hardness, which is extremely useful as a raw material component, particularly 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 commercially available anhydrous carbonates.

Conventionally, anhydrous sodium carbonate is 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 force positioning at a temperature of ℃.

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 90 μm to 110 μm. The light ash is generally used as a raw material for chemical industries such as food additives and dyes. Add water to the obtained light ash to make carbonic acid 1
It is produced by preparing 1 rum-water salt (Na=Cα·H2O) and then drying it at a temperature such that the outlet temperature of the dryer is 110°C to 170°C.

The reprint thus obtained generally has an apparent specific gravity of 1 or more and an average particle size in the range of 200μ to 400μ. It is also possible to obtain similar light ash or reprint by carbonation of caustic soda.

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

When using IJum as a raw material for synthetic detergents, either light ash or reprinted material can be used.
The method was to mix sodium carbonate with other detergent raw materials to form a slurry, and then dry the slurry with a dryer and granulate it simultaneously to obtain a detergent. 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 light ash has a small average particle size and a high particle hardness. Also, in reprinting, because the apparent specific gravity is large, it is easy to separate from other synthetic detergent raw materials. In addition,
When using light ash and juhan by dissolving them in water, light ash has an extremely small particle size and tends to coagulate and form lumps when placed in water, whereas juhan has a large apparent specific gravity, so it sinks to the bottom. , it has disadvantages such as the need to increase the stirring intensity to aid dissolution.

In order to eliminate these drawbacks, the present invention eliminates the need to make a slurry in the manufacturing process of synthetic detergents, and also makes it possible to add IJum (carbonated even after drying and granulation). This is a method for producing sodium carbonate, which allows the addition ratio of sodium carbonate to detergent raw materials to be freely adjusted, and at the same time is difficult to separate from other detergent raw materials.The present inventors completed the present invention as a result of intensive exploration. That's what I did.

The present invention provides an unprecedented method for producing sodium carbonate having extremely low apparent specific gravity, high dissolution rate in water, large average particle size, and high surface hardness.

That is, the present invention has a weight ratio of sulfur and lithium bicarbonate: sulfur carbonate)
At the same time or separately, water or an aqueous solution having a caking effect is lowered to a temperature of 40°C to 105°C, and the average particle size is preferably 200μ or more. and the apparent specific gravity is 0.4 to 0.
This is a method for producing porous sodium carbonate with high surface hardness, which has a pulverization rate of 8 inches or less at a 9-particle hardness and a dissolution rate in water of 40 seconds or less.

The most suitable method for producing sodium carbonate for use in synthetic detergents is as follows: After adjusting and homogenizing sodium bicarbonate and water at a specific weight ratio, as previously applied by the present inventors,
There are 6 ways to do this.

Although it is true that the desired IJium carbonate can be obtained by this method, it may be difficult to obtain IJIUM carbonate with a low powderization rate and a high surface hardness unless the conditions are strictly controlled. Ta.

Depending on the application, sodium carbonate is required to have even higher surface hardness, a larger average particle size, a lower apparent specific gravity of 0.4 to 0.9, and excellent dissolution rate.

Compared to the previously filed method, which required the use of an aqueous solution all at once, the present invention uses the solution separately, and in addition, water is added in the post-pressing process, so that the pressure is applied under mild or high water vapor pressure. There are characteristics. That is, the water or aqueous solution having a caking effect used initially is used primarily for agglomerating or granulating the powder, and then, after the force position, for example, I
Addition of water or aqueous solutions with caking action by means such as IJt fogging is used in particular to significantly increase the surface hardness.

A feature of the present invention is that only the surface layer of the sodium carbonate is particularly hard, making it difficult to powder.

For this purpose, the inside of the particle must be porous, and the surface layer must be
It is essential to have a denser layer.

In some cases, only the surface layer of IJum (i.e., carbonic acid) is hydrated by reacting with water or an aqueous solution having a caking action, and new water crystals, ie, Nag, are produced during the hydration reaction. Examples of aqueous solutions having a caking effect include inorganic salt aqueous solutions such as carboxylic cellulose, sodium silicate, etc.
Any of sodium lignin sulfonate, pulp waste liquid, starch liquid, etc. may be selected depending on the purpose. Among these, carboxymethylcellulose and sodium silicate are particularly preferred.

Although there is no limit to the amount added, it is not preferable to use more than the amount necessary to achieve the effect of increasing hardness. As a method for making only the surface layer of sodium carbonate react with water,
For example, warm water or an aqueous solution with a caking effect at 65°C to 10°C.
There is a method of spraying at a temperature of 9°C. The weight ratio of sodium carbonate (anhydrous equivalent) to water is 1:0.02-0.20.
It is important to desirably adjust the ratio to be 1:0.03-0100. Another embodiment variant is to increase the water vapor pressure at the temperature when the force is applied.

There is also a method of applying force while maintaining the sum water vapor pressure between 50 and 90 inches.

Water utilization reactions on the surface of sodium bicarbonate are promoted by applying force under high water vapor pressure.

As for the structure of the force position furnace, a continuous force firing furnace such as a tubular type is efficient, and the furnace is divided into a front half and a back half, and the first half is heated under normal low water vapor pressure, and the second half is heated under high steam pressure. The object of the present invention can be more effectively achieved by performing operations such as force positioning under water vapor pressure.

Note that the present invention can be carried out by appropriately mixing granular sodium bicarbonate and sodium carbonate or sodium carbonate hydrate obtained from the ammonia-soda method or the ammonium chloride-soda method as raw materials; The weight ratio of sodium carbonate:sodium carbonate (anhydrous equivalent) is 1:
It is necessary to adjust it to 0.2-5.0. 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 to sodium carbonate (anhydrous equivalent) is 1:02 to 5.
At the same time or separately, water or an aqueous solution having a caking effect is added at a temperature of 40°C to 105°C to give a ratio of 1.00%. Then, after heating at a temperature of 100 DEG C. to 300 DEG C., water or an aqueous solution having a caking effect is further reacted.

For example, when the mixing temperature is less than 40°C, the particle hardness becomes weak, and when it exceeds 105°C, the apparent specific gravity shows a value that is different from the target value, which is not preferable. Although these reactions usually complete within 10 to 20 minutes after mixing, it is not desirable to use a mixer to stir too vigorously.

In order to reduce the particle size of the thorium carbonate, vigorous stirring must be performed under appropriate stirring with consideration for crystal growth.

In addition, when the raw material contains carbonic acid (l) rum-water salt, it is desirable to adjust the amount of the aqueous solution used to a lower level. In addition, too much sodium carbonate
If too much water salt is used, the hardness of the resulting crystals may decrease slightly. As an example of reaction operation, a case will be described in which sodium bicarbonate, sodium carbonate, and water are mixed.

In the present invention, for example, to 100 parts of sodium bicarbonate, 100 parts of IJium carbonate and 50 parts of a hot aqueous solution are added.
Mix thoroughly for 0 minutes. (100 parts of sodium bicarbonate is carbonate) The IJium equivalent is approximately 63 parts, so the mixing ratio of sodium bicarbonate and sodium carbonate is 1=1 by weight.
carbonic acid) IJium equivalent ratio is 1:1.6. This mixed material is heated to a sufficiently high temperature (100° C. to 600° C., preferably 150° C. to 220° C.) to decompose the sodium bicarbonate and dehydrate the added water, followed by carbonation.)
3% by weight to IJum
The desired sodium carbonate is obtained by uniformly spraying wt% water.

A further characteristic feature of the production method of the present invention is that, although the reason for this has not been confirmed, sodium carbonate with an extremely large average particle size of 200 parts or more can be obtained, and the obtained carbonic acid can be obtained. IJum has an apparent specific gravity of C.
-, 4 to 09, and has unprecedented excellent properties such as a powdering rate of 8% or less in terms of particle hardness and a dissolution rate in water of 40 seconds or less.

In addition, in the present invention, the average particle diameter, apparent specific gravity, powdering rate,
The dissolution rate and heating loss are values calculated by the following measurement method, and the same applies to the Examples and Comparative Examples shown below.

(Average particle size) Sample 14.100g reduced with a 2-divider was weighed on a top balance (weighing 2
001/ ), transfer it to the top sieve of a stack of JIS standard sieves that are approximately appropriate for the particle size of the saucer and sample, cover it, and attach it to a rotary tube shaker.
After shaking for 7 minutes, the residue on the saucer and each sieve was weighed on a top balance (weighing 100.9), and the cumulative percentage of the nominal size μ of each sieve was calculated.
(The nominal size μ of the sieve that reaches more than 100 mm is the average particle size.

(Apparent specific gravity) Weigh sample 50.9, place it in a measuring cylinder with a capacity of 100 m1 (inner diameter approx. 27 a), and pound it thoroughly on a thick rubber plate, being careful not to apply too much force, until the minimum volume is kml. Then, calculate the apparent specific gravity using the following formula.

(Powdering rate) The average particle size of the material to be measured is 200μ to 600μ.
For μ samples, take out 120g of the sample, weigh 50g of the long mixture, put it in an intermediate saucer together with 15 aluminum discs with a weight of 11 and a diameter of 20 rugs, and shake it for 5 minutes in a shaker (at this time Do not use tataki) 1~
After the operation, the sieved portion of the above (average*3 average particle size) was weighed again to calculate the percentage. Also, if the average particle size of the material to be measured is about 50μ to 150μ,
111'5, 149μ, 74jt and 44β respectively
use.

The correspondence is indicated by a box.

(Dissolution rate) Diameter 165 cranes, height 1801! Pure water a in the + glass container
A stirrer with 4 stirring blades 25 mm thick, 12 mm wide and 58 mm long was rotated at 55 rpm, 200 g of the sample was added at once, and 2 ml was dissolved every 5 seconds.
Lf: Measure the time required for the concentration of dissolved sodium carbonate to reach 240 g/7I by sampling and titration.

(Heating Loss) Weigh 10g of the sample correctly, dry it in an electric furnace or dryer adjusted to 280°C to 300°C for about 3 hours, cool it in a Tenkater, then measure its weight and calculate according to the following formula: Calculate the loss on heating.

The experiment was conducted 6 times according to the above procedure, and the average value was taken as the heating loss.

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

Example 1 and Reference Example 1 Typed sodium carbonate and light ash obtained by the ammonia-soda method were simultaneously supplied to a mixer in the proportions shown in Table 1.
While mixing and stirring, 60°C warm water was added using a spray nozzle.

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

These mixtures were heated in the same manner to a temperature of 18
Sodium carbonate is obtained by uniformly spraying hot water at the proportions shown in Table 1 onto the sodium carbonate obtained by heating at 0°C.

For comparison, make a mixture as described above and carbonate it by heating it in the same way using a heating machine) l) Obtain rum.

The average particle diameter and apparent specific gravity of these IJium carbonates.

Powdering rate, dissolution rate, and loss on heating were measured. The results are shown in Table 1.

Example 2 In Example 1, sodium bicarbonate and sodium carbonate obtained by the caustic noda liquid carbonation method were used instead of the assembled sodium carbonate and light ash obtained by the ammonia-soda method among the raw materials, and - Sodium carbonate was produced by uniformly spraying warm water at the proportions shown in Table 1 onto the sodium carbonate obtained by operating the mixer under the conditions shown in Table 1. The results of (a) are shown in Table 1.

-241 In Example 1, O, S was used instead of the hot water solution among the raw materials.
Example 1 except that a warm aqueous solution of W sodium eusilicate was used.
Sodium carbonate was produced under the same conditions.

The results are shown in Table 1.

Table - wt% in parentheses Warm aqueous solution A: Warm aqueous solution B: 0.Swt sodium tisilicate aqueous solution C:
Hot Aqueous Solution Example 4 Wet sodium bicarbonate was obtained by carbonation of a 25 w% aqueous caustic soda solution. 1ookg of this wet sodium bicarbonate
/hour (dry pace) and carbonate) 120k IJum
The mixture was supplied to a paddle mixer at a rate of 50 kg/hour, and hot water at 50° C. was sprayed at a rate of 50 kg/hour. The mixture, which has become agglomerated particles, is then supplied to a closed rotary cylindrical dryer, and steam is directly blown into it so that the potential temperature is 170°C to 200°C and the water vapor pressure is 005 to 07 of saturated steam at 170°C. I adjusted it while doing so.

The average residence time of the particles was approximately 30 minutes.

The average particle size of the obtained sodium carbonate was 350μ.

The apparent specific gravity is 065. The powdering rate was 3%, the dissolution rate was 20 seconds, and the weight loss on heating was 5.1 inches.

Patent Applicant Toyo Soda Kogyo Co., Ltd. Procedural Amendment (Method) % Formula % 2 Name of Invention Method for Producing Porous Liumium Carbonate with High Surface Hardness 3 Relationship with the Amendment Case! 1. 'l' Approval M 1 person 4 Date of amendment order November 8, 1980 5 Specification subject to amendment 6 Contents of amendment Type of statement Seal 7 Attachment Type-printed Ming a + So 1 copy

Claims (1)

[Claims] While adjusting the N amount ratio of sodium bicarbonate to sodium carbonate (anhydrous equivalent) to a ratio of 1:02 to 500, water or an aqueous solution having a caking effect was added at 40°C at the same time or separately.
Add at a temperature of ~105°C, then 100°C to 500°C
After heating at a temperature of 100 ml, the carbonic acid is further reacted with water or an aqueous solution having a caking effect to produce carbonic acid having an apparent specific gravity of 0.4 to 0.9 and a dissolution rate in water of 40 seconds or less.