JPS5924728B2 - Production method of chlorine-containing basic aluminum sulfate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing chlorine-containing basic aluminum sulfate.

Conventionally, many studies have been conducted regarding the production of basic aluminum salts, and various methods have been put into practical use.

A commonly used method for producing basic aluminum sulfate is to dissolve alumina hydrate obtained by the Bayer method in sulfuric acid to obtain aluminum sulfate, and then remove the sulfate radicals from this with calcium hydroxide or calcium carbonate. , A method of dissolving aluminum hydroxide obtained by contacting an alkali aluminate with carbon dioxide gas or sulfur dioxide gas, and a method of dissolving water-insoluble basic aluminum sulfate obtained by reacting aluminum sulfate with an alkali aluminate with aluminum sulfate. There are known methods of dissolving it.

In general, the main factors that influence the quality characteristics of this kind of basic aluminum sulfate are concentration of solution, order of addition, temperature 1
These include the pH of the reaction system.

8 These factors must always be considered in order to obtain the desired product, and even slight differences in operating conditions can greatly alter the quality of the product.

The present inventors have diligently studied these points and have completed a method for producing basic aluminum sulfate containing chloride ions.

That is, 1 the present invention is a substantially water-insoluble chlorine-containing aluminum hydroxide compound expressed by the general formula: % formula % (1) obtained by reacting aluminum chloride with an alkali aluminate, and the basicity of the product is 50%. The present invention relates to a method for producing chlorine-containing basic aluminum sulfate, which is characterized by adding an acid aluminum salt aqueous solution containing aluminum sulfate and reacting at 80° C. or lower and normal pressure under the following conditions.

The chlorine-containing aluminum hydroxide compound obtained in the present invention preferably falls within the range expressed by the following formula: % formula % For this purpose, the amount of aluminum chloride aqueous solution added to the sodium aluminate aqueous solution is such that the pH of the reaction system is 4. Adjust so that it is in the range of 5 to 6.5.

When the pH is below 4.5, the produced aluminum hydroxide is eluted into the sap and the yield is reduced, and when the pil is north of 6.5, the obtained aluminum hydroxide does not dissolve in the aluminum sulfate aqueous solution and becomes a paste. A similar dispersion is produced.

The alkali aluminate may be any ordinary commercially available product, but it is preferable that the alkali content be as low as possible.

The concentrations of the aqueous sodium aluminate solution and aluminum chloride are adjusted to such a level that the temperature of the solution during the reaction can be maintained at 30° C. or lower.

Preferably, sodium aluminate is dissolved in about 6 times as much water and aluminum chloride is dissolved in about 4 times as much water.

When the temperature of the liquid during the reaction is 30°C or higher, the solubility decreases significantly.

After completion of the reaction, the mixture may be aged for 30 minutes and then filtered as is. Alternatively, to improve filterability, the mixture may be heated at 40 to 70°C and then filtered.

The above chlorinated aluminum hydroxide is hydrochloric acid or sulfuric acid.

Easily soluble in aluminum sulfate, aluminum chloride, etc.
When dissolving with hydrochloric acid, sulfuric acid, and aluminum sulfate aqueous solutions, heating above 80°C is not preferred, but when dissolving with aluminum chloride solution, it is stable up to 100°C.

During dissolution, the basicity is adjusted to 50% or less.

The basicity is preferably around 45%; if it exceeds 50%, it becomes cloudy at temperatures above 70°C and cannot be dissolved transparently.

The chlorine-containing basic aluminum sulfate according to the present invention is Al
Contains 0.1 to 30% by weight of chlorine based on 203.

Hydrolysis with water tends to be faster when the chlorine content is greater than the above amount, so it can be changed as appropriate depending on the purpose.

If the chlorine content is less than the above amount, it is not preferable because it tends to self-decompose and become cloudy when stored at around 35°C.

The basicity can be adjusted arbitrarily by adjusting the amount of acid aluminum salt aqueous solution containing aluminum sulfate when dissolving chlorine-containing aluminum hydroxide, but if the basicity is 46% or more, use chlorine-containing aluminum sulfate synthesized with a basicity of around 46%. Ca O
, Ca(OH)2. CaCO3.

MgO, Mg(OH)2. MgCO3, Na2CO3,
It may be prepared by adding an alkali compound such as NaOH.

The chlorine-containing basic aluminum sulfate obtained by the present invention is excellent as a flocculant, and has a particularly remarkable flocculating effect on water containing iron ions. It is several times more effective than flocculants such as basic aluminum sulfate and basic aluminum chloride.

In addition to its use as a flocculant, the chlorine-containing basic aluminum sulfate according to the invention is also used as a size fixing agent for paper manufacturing.

Not only can it be widely used as a raw material for alumina sol production, medicinal antacids, and pharmaceutical aluminum salts, but the soluble aluminum hydroxide obtained by neutralization can be used as a gas adsorbent, catalyst carrier, etc. by dry heat treatment after drying. is also applicable.

Furthermore, aluminum chloride was added to basic aluminum sulfate obtained by dissolving insoluble aluminum hydroxide from aluminum sulfate, aluminic acid, and lithium, and the chlorine content was 0.1 per AI□03 minutes. ~
When comparing 30% by weight of chlorine-containing basic aluminum sulfate with the chlorine-containing basic aluminum sulfate of the present invention,
The latter is more homogeneous and has better storage stability, even after long-term storage of 6 to 12 months.
(0% or more) has the advantage of generating less precipitates.

Example I 50 g of sodium aluminate containing 321% of A1□0321% and 2017% of Na is dissolved in 300 g of water, and AI is added to the solution.

50 gf of an aqueous aluminum chloride solution containing 1.5% and 22% Cl. A solution diluted with 200 g of water is gradually heated at a temperature of 27 to 29°C, stirred for 30 minutes, and then warmed to 50°C and filtered. .

Add 500 ml of water and refiltrate to obtain 150y of water-containing aluminum hydroxide.

150 g of the aluminum hydroxide was dispersed in 210 g of an aluminum sulfate aqueous solution containing 38% A12.

After being maintained at 65-70°C for 1 hour and filtered, 320g of F solution (Al2O2 10, 17%, SO4 16, 3%) was obtained.

CIo, 023%, basicity 45.5%).

In order to investigate the flocculation effect when the chlorine-containing basic aluminum sulfate aqueous solution obtained in this example was used for water purification treatment, 1 Japan Water Works Association standard polyaluminum chloride (A12
o3 10.06%, basicity 50.3%, SO4 3.0%
) and the results of a comparison test using a jar test are as follows.

Jar test conditions Rapid stirring 12Orpm Slow stirring for 2 minutes
2'Or pm 8 minutes standing time
When using the product of this example for 10 minutes, there was little decrease in pH of the treated water.
It has the advantage of generating flocs quickly.

Example 2 Sodium aluminate containing 21% A1203 and 2017% Na 50! ! was dissolved in 300 g of water, and a solution prepared by diluting 55 g of an aluminum chloride aqueous solution containing 11.5% and 0122% of A1□03 with 200 g of water was gradually added to the solution at a temperature of 27 to 29°C, and stirred for 30 minutes. After heating to 50°C and filtering, 155 g of hydrous aluminum hydroxide was obtained.

155 g of the aluminum hydroxide was dispersed in 200 g of an aluminum sulfate aqueous solution containing 2038% Al.

After being kept at 65-70°C for 1 hour, it was filtered out to produce 330g of mud (Al5O120.11%, 5O415.09%.

CI 2.71%, basicity 45.1%).

The thus obtained chlorine-containing basic aluminum sulfate was slurried with 5 g of magnesium hydroxide and 20 ml of water and added at 55°C, aged for 1 hour and filtered to give a P solution of 3359 (Al□039.98%, 80414. 9%, CI
2.63%, -Basicity 52.6%).

In order to investigate the flocculation effect when this example product was used for water purification treatment, 1 Japan Water Works Association standard polyaluminum chloride (A
l□0310.13%, So, 2.85%.

The results of a comparative test using a jar test with Cl 82% and basicity 52.3% are as follows.

The conditions for the jar test were the same as in Example 1.

Water quality of raw water (tap water + ferric chloride): Turbidity 12° pH 6,02 Water temperature 23°C Water quality of raw water (tap water + ferric chloride): Turbidity 50° pH 7,2 Water temperature 5°C or more coagulation It is clear from the test that the product of the present invention is superior.

200 ml of the product of this example is diluted with 800 ml of water, stirred at 25-27°C for 30 minutes, and then adjusted to pf (7.5) using about 50 m# of 25% aqueous sodium hydroxide solution.

When heated to 70℃, filtered, washed with water, and dried below 70℃, 1
Aluminum hydroxide soluble in 0% hydrochloric acid is obtained, which can be used as a raw material for antacids.

1200 to 1500 to perform similar water splitting using basic aluminum sulfate that does not contain chlorine ions.
ml of water is required.

Furthermore, when using polyaluminum chloride as specified by the Japan Water Works Association, the water decomposition rate is slow and a large amount of sulfur hydroxide is required, which accounts for 10% of the resulting product.
The solubility in hydrochloric acid is inferior to that of the product of this example.

Claims (1)

[Claims] 1. A substantially water-insoluble chlorine-containing aluminum hydroxide compound expressed by the general formula: % formula % obtained by reacting aluminum chloride with an alkali aluminate, and the basicity of the product is 50% or less. A method for producing chlorine-containing basic aluminum sulfate, which comprises adding an acid aluminum salt aqueous solution containing aluminum sulfate under the following conditions and reacting at 80° C. or lower and normal pressure. 2. The method according to item 1, wherein the pH of chlorine-containing aluminum hydroxide is adjusted to a range of 4.5 to 6.5. 3. The method according to item 1, wherein the reaction between aluminum chloride and alkali aluminate is carried out at a temperature of about 30°C or less. 4. The method according to item 1, wherein the acid aluminum salt aqueous solution is an aluminum sulfate aqueous solution. 5. The method according to item 1, wherein the acid aluminum salt aqueous solution contains aluminum chloride in a range such that the chlorine content is 0.1 to 30% by weight based on the AI□03 min of the chlorine-containing basic aluminum.