JPS59474B2 - Kankousei karihiriyou no seizouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides 20.Al2O which is soluble in potassium-containing minerals.
This invention relates to a method for producing a slow-release potash fertilizer containing 3.2 S+02 as a main component.

The main component of potassium-containing minerals is K2O・Al2O3・6S
io 2, and the result obtained by processing this is 20・A
Since 12O3.2 S t 02 is insoluble in water but only slightly soluble, it is known to be used as a slow-release potash fertilizer.

As a treatment method, a dry method in which a potash compound is mixed with a potash-containing mineral and fired (for example,
), or a wet method in which a potash-containing mineral is mixed with an aqueous solution of a potash compound and treated with heat and pressure (for example,
-4962) are being considered.

However, both methods have their advantages and disadvantages, and it is difficult to say which method is more economically advantageous; however, the wet method has the following advantages over the dry method.

(1) Since the reaction temperature is low, the amount of heat required is small.

(2) It is easy to carry out the reaction uniformly.

(3) It is easy to take out the reaction product.

(4) There is no need to worry about pollution caused by gas generated during high-temperature firing.

By the way, the conventionally proposed wet method not only has the disadvantage of an extremely low yield since approximately twice the amount of water-soluble potash is produced as a by-product, but also has the following disadvantages: ing.

(1) A large amount of 20·n S t 02 is produced as a by-product, and this forms a gelatinous substance, making it extremely difficult to filter and wash with water.

Furthermore, if a large amount of water is used to improve filterability, a huge amount of heat will be required for concentration to recover potassium compounds.

(2) It is difficult to recover the potassium compound used in excess or the potassium compound produced as a by-product.

For example, when recovering and reusing by-product water-soluble potash compounds, it is necessary to add lime or dolomite to form a tropic potash solution.

Therefore, the present inventors conducted various studies with the aim of finding a method that is even better than the conventionally proposed method for producing slow-release potash fertilizer using a wet method.

As a result, an aqueous solution of a potash compound and an aluminum compound were mixed with the crushed material of the potash-containing mineral, which was then heated and heated.
If the soluble potassium compound is separated and obtained after pressure treatment,
All the drawbacks of conventional methods can be improved,
extremely economically from potash-containing minerals.
The present invention was completed by discovering that it is possible to produce a slow-release potash fertilizer containing 2SiO2 as a main component.

Potassium-containing minerals used in the present invention include potassium feldspar, potassium quartz trachyte, sericite, vermiculite, tourmaline, glauconite,
Any mineral containing potash such as iron alum stone is effective, and it is preferable to use these by crushing them into a 100-inch mesh.

In addition, as an aqueous solution of potassium compound, K2CO3゜KOH
Aqueous solutions such as A
Examples include A'(OH)s, A 13203, and the like.

These mixing ratios determine the yield of slow-release potash fertilizer,
Or, considering its filterability etc., K2O15iO2(
molar ratio) is 0.6 to 1.0, Al2O3/Si02
It is preferable to mix an aqueous solution of a potash compound and an aluminum compound with respect to the ground material of a potash-containing mineral so that the C molar ratio) is 0.4 to 0.6).

Next, this mixture is heated for 5 to 15 minutes at a temperature of 150 to 350°C.
After heating and pressurizing at a pressure of 0 kg/ffl for 1 to 24 hours, cooling, filtering, and washing with water, a slow-release potash fertilizer containing 20.Al2O3.2SiO2 as a main component is obtained.

In the present invention, in addition to an aqueous solution of a potash compound, an aluminum compound is mixed in advance with the potash-containing mineral, so that water-soluble potash compounds (K2O・n5i02)*, which are produced as by-products in the heat and pressure treatment process in the conventional method, are eliminated. , is not produced, it is possible to produce slow-release potassium fertilizer at an extremely high yield (yield almost 100%) compared to conventional methods.

In addition, since almost no water-soluble potassium compound is produced as a by-product during the heat treatment process, all the drawbacks of conventional methods can be overcome.

That is, it is extremely easy to filter and wash the product with water, and it is also easy to recover the potassium compound used in excess.

As described above, the present invention is a novel method for producing slow-release potash fertilizer that is extremely superior to conventional methods.

Next, examples of the present invention and comparative examples will be given to specifically explain the present invention.

Table 2 shows the properties of the slow-release potassium fertilizers manufactured by each side.

The potassium-containing minerals used on each side were crushed potassium feldspar produced in the Yamaguchi region and potassium quartz trachyte produced in the Oita region (all 100-inch mesh) having the chemical composition shown in Table 1.
It is.

Example 1 1,000 g of a 65% KOH aqueous solution was added to 946 g of crushed potassium feldspar (K2O15iO2 (molar ratio) 20.7).
, and powdered Al(OH)3 with a purity of 95% at 509
,! li'(1'J303/S 1o2 (molar ratio)
= 0.5J mixed and 12kg/crtt at a temperature of 200℃
Heat and pressure treatment was carried out with stirring in an autoclave for 12 hours at a pressure of .

The obtained product was cooled and filtered, washed with water, and dried to obtain 1581 g of a slow-release potash fertilizer containing 20.Al2O3.2 S io 2 as a main component.

Examples 2-3 Heating and pressurizing treatment conditions: 49 kg/c at a temperature of 280°C
An experiment was conducted in the same manner as in Example 1, except that the temperature was 2 hours at a pressure of , l, 580g (Example 2), 1.581g
(Example 3) Obtained.

Comparative Example An experiment was conducted in the same manner as in Example 1, except that Al(OH)3 was not mixed, and 608 g of slow-release potassium fertilizer was obtained.

Example 4 1,000 g of a 1.48% KOH aqueous solution was added to 845 g of crushed potassium feldspar (2O/S t 02 (molar ratio) - 0, 6 bar and powdered A7 (OH) with a purity of 95%). 3
597 g (A12C)3/S t 02 (molar ratio) = 0.6 J and mixed at 30 kg/i at a temperature of 250°C.
Heat and pressure treatment was performed with stirring in an autoclave for 10 hours at a pressure of .

After cooling and filtering the obtained product, it was washed with water and dried to obtain 1.413 g of slow-release potassium fertilizer.

Example 5 637g of crushed potassium quartz trachyte was added with 2CO3 to 60%.
1.000 g of an aqueous solution of 2O/S i 02(
molar ratio) = 0.7] and powdered Al2 with a purity of 98%.
Mix 277 g of O3 (A40a / S 102 (molar ratio) = 0.5 J, 30 kg/i at a temperature of 250 ° C.
Heat and pressure treatment was performed while stirring in an autoclave for 5 hours at a pressure of .

After cooling and filtering the obtained product, it was washed with water and dried, and a slow-release potassium fertilizer was added to the solution at a concentration of 1.13! I got it.

Claims (1)

[Claims] 1. Production of a slow-release potash fertilizer characterized by mixing an aqueous solution of a potash compound and an aluminum compound with a crushed product of potash-containing minerals, then subjecting the mixture to heat and pressure treatment, and then separating and obtaining a soluble potash compound. Method.