JPH01282119A - Easily disintegrable granular composition - Google Patents

Abstract

PURPOSE:To prevent pulverization by combining salt of alkaline earth metal and acid with saccharose as disintegrable binder for mixed powder consisting of hydroxide and oxide of alkaline earth metal. CONSTITUTION:The granular composition is obtd. by adding a liq. dissolving saccharose (e.g., cane sugar) and one or more kinds of salt of alkaline earth metal and acid (e.g., calcium nitrate) in water in advance, by granulating and by drying. Thereby, since the granular composition is prevented from pulverizing, generation of dust is prevented and the composition is easily handled. Besides, the composition retains its high hardness for a long time period and is easily disintegrated in water or soil. The hardness and the degree of the disintegrability in water and soil of the granulated composition are arbitrarily controlled by controlling the amt. of cane sugar and the salt of alkaline earth metal and acid to be added.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECT-1 OF THE INVENTION The present invention provides a granular product of an alkaline earth metal hydroxide or oxide which prevents dust generation and is easy to handle, and which is suitable for use in water or soil. Particulate compositions that are easily disintegrated within.

Slaked lime, which is a type of alkaline earth metal hydroxide, is generally widely used as a neutralizing material, but because it is a fine powder, it scatters a lot when used, so it is necessary to make it easier to use. As a measure to prevent this scattering, granulation has been used.

The granulation properties of slaked lime are extremely good, and there are two methods: dry method and wet method.

In the dry method, slaked lime powder is pressure-molded, then crushed and classified to the desired particle size to obtain a granulated product.Since each grain is not spherical but an amorphous agglomerate, it has no commercial value. low.

In the wet method, water is simply added to impart a transfer motion to granulate the granules, or the hydrated granules react easily with carbon dioxide gas in the atmosphere during the drying process to produce calcium carbonate, which is sparingly soluble in water. Therefore, the strength of the granules increases or they lack disintegration after application.

In addition, since slaked lime powder is a fine powder with a large surface area, it requires a large amount of moisture during granulation, usually about 30% of the outside moisture content, and also has the drawback of requiring a large amount of drying energy.

In order to compensate for such drawbacks of the wet method, Japanese Unexamined Patent Publication No. 60-1
In No. 4694, slaked lime is wet-granulated by adding 0.5 to 1.0% calcium chloride to Steffen waste liquid, valve waste liquid containing likuninsulfonic acid as a main component, alcohol fermentation waste liquid, etc., and the same applicant as the present invention [511061-1]
No. 63116 proposes adding calcium chloride to slaked lime and subjecting it to wet granulation to improve the disintegration of the granules in water or soil.

However, the former is undesirable because Steffen waste liquid, valve waste liquid, alcohol waste liquid, etc. are all black or brownish and will be colored when mixed with slaked lime, and the latter requires a slightly larger amount of calcium chloride, which is around 10% of the slaked lime. Therefore, it has drawbacks such as a decrease in the main components.

On the other hand, in Japanese Patent Publication No. 42-1453, when granulating strongly alkaline fertilizers such as lime and magnesia, sucrose and an anionic or nonionic surfactant are added together with water. A method of generating soluble lime sucrose salt and increasing disintegration in soil by the wetting action of a surfactant is shown.

Even when used alone, sucrose acts specifically as a binder during wet granulation by adding water to strongly alkaline fine powders such as slaked lime, magnesium hydroxide, and lightly calcined magnesia, and has a binding agent of 3 to 5 hairs per powder. When the product is granulated and dried with the addition of It was found that even if it was left sealed in a polyethylene bag for about 10 days at a room temperature of around 20° C., it turned into powder and could not be put to practical use.

In the present invention, the alkaline earth metal hydroxide that prevents dust generation and is easy to handle is a granular oxide product that maintains high hardness for a long time. An object of the present invention is to provide a granular composition that easily disintegrates in water or soil.

1. Constitution of the Invention C・t “The granular composition that disintegrates easily in water or soil according to the present invention is
Sucrose and salts of alkaline earth metals and acids are added to one type of powder selected from the group consisting of hydroxides and oxides of alkaline earth metals or a mixture of two or more types of powders and granulated. This makes it possible to obtain a granular composition that has appropriate strength and does not change over time without impairing the disintegration properties of the granules in water or in soil.

The hydroxides or oxides of alkaline earth metals to which the present invention is applied are those that are generally manufactured and sold as granules and used, and the hydroxides include slaked lime, magnesium hydroxide, etc. Examples include light calcined magnesia, and these powders are used alone or as a mixture.

It is generally convenient to use sucrose (sugar) as the sucrose, but beet sugar or 11 types containing sucrose can also be used. Salts of alkaline earth metals and saccharose, ie, calcium saccharate, magnesium saccharate, barium saccharate, etc., can also be used.

On the other hand, salts of alkaline earth metals and acids that are added at the same time as sutucarose include calcium chloride, magnesium chloride, calcium nitrate, magnesium nitrate, calcium formate, magnesium formate, calcium acetate, magnesium acetate, barium chloride, barium nitrate, etc. , from these, as long as it does not interfere with the intended use of the granular material, it can be appropriately selected and used.

The following is a detailed example of granulation by adding slaked lime powder as an alkaline earth metal hydroxide, Ma as a sucrose, and calcium nitrate (lime nitrate) as a salt of an alkaline earth metal and an acid. In the following explanation, saccharose and an alkaline earth metal and an acid are added to one powder or a mixture of two or more powders selected from the group consisting of hydroxides and oxides of other alkaline earth metals. It is also applied when adding salts and granulating and drying.

Between sucrose and slaked lime, three types of sucrose-calcium (CI2822012 ・CaO), sucrose dicalcium (C+2Hz□O+2・2CaO), and 24-saccharide tricalcium (CI2Hazo 12 ・3CaO) are present between sucrose and slaked lime. It is known to produce the following compounds.

Among these compounds, the former two have high solubility in water, but sucrose tricalcium has low solubility in water.

The reason why sucrose is added as a disintegrating binder in the wet granulation of slaked lime is to focus on the fact that the calcium saccharate that is produced is an aqueous solution. In the case of granules of 1 size, the strength of the granules is low when the water is dried, but they show very good disintegration in water or soil.

However, for reasons that are not clear, the hardness of the granules decreases over time and becomes powdered in about 10 days when left indoors.

This tendency to powder becomes more pronounced as the standing temperature increases, and it was found that powder was formed overnight at 70°C and in about 24 hours even at 50°C, making it impossible to put it to practical use.

This decrease in hardness is more pronounced as the water content of the granules increases, so it is thought that the initially generated water-soluble calcium saccharate reacts with the residual slaked lime to produce high-lime type saccharates. The rates are amorphous and the identification method is difficult and unclear.

As a method for preventing this pulverization, it has been found that adding a small amount of alkaline earth metal and acid salts, such as lime nitrate, during wet granulation can prevent a decrease in the hardness of the granulated product.

The hardness and disintegration properties of the granules in water and soil can be arbitrarily designed by adjusting the amount of sucrose added and the amount of salts of alkaline earth metal and acid.

In general, increasing the amount of sucrose improves the disintegration properties, and salts increase the strength of the granules and reduce their change over time, but if they are mixed in large amounts, they worsen the disintegration properties.

Regarding sucrose used as a raw material, dispersibility is better if it is dissolved in water beforehand and then mixed in.

Alternatively, a part of the slaked lime and sucrose may be dissolved in water to prepare an aqueous solution of sucrose or dicalcium salt in advance, and this may be added to the remaining slaked lime for granulation.

Many commercially available sucrose (for general food use) contain glucose, and although glucose also produces calcium salts, it has low solubility in water, so it is advantageous to choose a product with as much sucrose as possible.

[Examples and Comparative Examples] Powder was put into a Henschel mixer with an internal volume of 1001 according to the raw material formulation shown in Table 1, and a solution in which the required amount of water, sugar or calcium saccharate, and salts had been dissolved in advance was added all at once. Thereafter, the blades were rotated at a circumferential speed of 20 m/sec, and stirring was continued for about 20 to 30 seconds until the powder was kneaded and granulated to a particle size of about 1 to 4 mm.

Dry this material in an IIOoC electric hot air dryer until it becomes completely dry, being careful not to react with carbon dioxide gas.2.
Only the sieved granules with a size of 80 to 2.38 mm were used as samples for measuring physical properties.

The sample was immediately sealed in a polyethylene bag to prevent it from absorbing carbon dioxide gas in the air, and after being placed in an apparatus at a predetermined temperature for a predetermined length of time, the crushing strength and water disintegration of the granules were examined, and the results are shown in Table 2. I got it.

(Margin below) Table 1 Table 2 (Part 1) Table 2 (Part 2) The test method is as follows.

The crushing strength of 10 grains having a diameter of 2.83 to 2.38 mm was measured using a hardness tester using a hardness tester, and the crushing strength was expressed as an average value.

In the K Rimon 1 water disintegration test, 50 samples were placed on a 2000JLm wire sieve, placed in a container large enough to fit the sieve, and clean water was gently poured into the sample until the sample was fully immersed in water. After leaving it in the room for one night, the sieve was gently taken out, the undisintegrated particles remaining on the sieve were determined, and the remaining percentage was determined.

Comparative Example 1 is a case where 5% by weight of sucrose is added to slaked lime and granulated. Although the disintegration in water is good, the hardness of the granulated product decreases over time, and the crushing strength decreases from 482g immediately after production to 20%.
Even at 50°C, the weight drops to 95g after 7 days, and at temperatures above 50°C, it turns into powder after 7 days, making it impossible to put it to practical use.

On the other hand, in Examples 1 to 4, it was possible to prevent the hardness of the granules from decreasing without impairing the disintegrability in water.

Furthermore, in Comparative Example 2, monocalcium saccharate was used instead of sucrose, but the tendency was similar to that of Comparative Example 1, and when 0.5% by weight of calcium nitrate was added as in Example 5, the hardness decreased. It was possible to prevent changes over time.

Such a phenomenon was observed in Example 7 using magnesium hydroxide or lightly calcined magnesia (magnesium oxide) as powder.
．． The same was true for case No. 8.

A granular product of alkaline earth metal hydroxide or oxide that prevents the generation of dust and is easy to handle, maintains high hardness for a long time, and easily disintegrates in water or soil. A granular composition is obtained.

Claims (1)

[Claims] Saccharose and salts of alkaline earth metals and acids are added to one type of powder selected from the group consisting of hydroxides and oxides of alkaline earth metals or a mixture of two or more types of powders and granulated. A granular composition that easily disintegrates in water or soil.