JPS5912625B2 - Method for producing slow-release potassium fertilizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides 20., M2O3
-2 This relates to a method for producing a slow-release potash fertilizer containing S t 02 as a main component.

The main component of potassium-containing minerals is K2O-M2O3.6SiO
2, and the result obtained by processing this is 20・AI! 20
3.2 S io 2 is insoluble and soluble in water, so
It is known to use this as a slow-release potash fertilizer.

Conventionally, by mixing potash-containing minerals and potash compounds and firing the mixture, 20.Al2O3.2
Various methods for manufacturing S t 02 have been proposed.

(For example, Special Publication No. 38-17394, No. 38-173
No. 95, No. 43-7816).

However, in all of these conventional methods, even if the reaction is sufficiently carried out, approximately twice the amount of water-soluble potassium as water-soluble potassium is produced as a by-product, so the yield is extremely low. It also has some drawbacks.

(1) The fired product adheres to the wall of the firing furnace and is difficult to remove.

(2) It is extremely difficult to wash and filter the fired product.

(3) Potassium volatilizes violently during firing.

(4) Severe foaming due to steam and gas generated during firing causes a reduction in reaction rate.

Therefore, the present inventors conducted various studies with the aim of improving the various drawbacks of these conventional methods.

As a result, a potassium compound and an aluminum compound were mixed with the crushed product of potassium-containing mineral, and then this was mixed with 800 to 1,3
If the soluble potash compound is separated and obtained after firing at 00°C, all the drawbacks of the conventional method can be improved, and KO-A720 can be produced from potash-containing minerals extremely economically.
3.2 It was discovered that a slow-release potash fertilizer containing S io 2 as a main component can be produced, and the present invention was completed.

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 potassium compounds, K2CO3, KOH, etc.
Furthermore, as an aluminum compound, yl (0H)3
, Al2O3, etc.

These mixing ratios determine the yield of slow-release potash fertilizer,
Or, considering the filterability of the fired product, K20/5i0
2 (molar ratio) is 0.5 to 1.0, Aj? 203/5i
It is preferable to mix the potassium compound and the aluminum compound with respect to the pulverized material of the potassium-containing mineral so that the molar ratio of 0.02 to 0.8 is 0.25 to 0.8.

Next, this mixture was heated at 800 to 1,300°C for 1 to 4 hours.
By firing in an electric furnace or rotary kiln for hours, and cooling the resulting fired product and washing and filtering it with water, a slow-release potassium fertilizer containing resoluble 2O-At203.2Sr02 as a main component is obtained.

In the present invention, an aluminum compound is mixed in advance with the potassium-containing mineral in addition to the potassium compound, so in the conventional method, water-soluble potassium compounds (K2O
・Since no n5i02) is produced, slow-release potassium fertilizer can be produced at an extremely high yield compared to conventional methods.

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

In other words, the fired product does not adhere to the walls of the kiln, making it extremely easy to wash and filter the fired product, and since there is no bubbling caused by water vapor and gas generated during firing, the reaction rate does not decrease, and the potash Volatilization is also extremely low.

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 mineral used on each side was crushed potassium feldspar (100-inch mesh) produced at the Katakura Mine in Ube City, Yamaguchi Prefecture, and having the chemical composition shown in Table 1.

Example 1 Add 8.60 kg of powdered 2CO3 of 99% purity to 10.0 kg of crushed potassium-containing mineral CK20/S + 0
2 (molar ratio)=O,,7] and 3.61 kg of powdered At(OH)3 with a purity of 95% [At203/5iO
2 (molar ratio) 20, 4] were mixed and fired in an electric furnace at 1,000°C for 3 hours.

The obtained baked product was cooled, 20 tons of water was added, stirred for 10 minutes, and then filtered.

Repeat this filtration operation three times, dry, and remove the soluble
・Slow-release potash fertilizer whose main ingredient is At203.2 S r 02 at 14.20! I got 9.

Examples 2-3 The amount of At(OH)3 added was 5.35-kg in Example 2.
CAt203/S i O2 (molar ratio) -〇, s'
:l, 7.09 kg in Example 3 CAt203/S
Example 1 except that 102 (molar ratio) = 0.6'l
An experiment was carried out in the same manner as in Example 2, and 16.28 kg (Example 2) and 17.34 kg (Example 3) of slow-release fertilizer were obtained.

Comparative Example I An experiment was conducted in the same manner as in Example 1, except that Atgu0H) 3 was not mixed, and 10.10 kg of slow-release potassium fertilizer was used.
Obtained.

Comparative Example 2 An experiment was conducted in the same manner as in Example 1, except that the firing temperature was changed to 700°C.

Comparative Example 3 An experiment was conducted in the same manner as in Example 1, except that the firing temperature was changed to 1,400°C.

Example 4 6.30 kg of granular KOH with a purity of 90% was added to 10.0 kg of crushed potassium-containing mineral [K20/S 1o2 (
molar ratio) = 0.6), and powdered At2 with a purity of 98%
3,39 kg of 03 [At203/5iO2 (molar ratio)
=0.5) After mixing and pulverizing, the mixture was fired in an electric furnace at 900°C for 3 hours.

The obtained baked product was filtered in the same manner as in Example 1 to obtain 16.55 kg of slow-release potassium fertilizer.

Example 5 65% KOH aqueous solution was added to 10.0 kg of crushed potassium-containing mineral at 12.41 (K20/5i02 (molar ratio) =
0.8), and 35 kg of powdered Az(OH)3 with a purity of 95% (At203/5102 (molar ratio) = 0
．． 5) After mixing and pre-drying until almost all moisture was removed, the mixture was fired in an electric furnace at 1,200°C for 2 hours.

The obtained baked product was filtered in the same manner as in Example 1 to obtain 16.42 kg of slow-release potassium fertilizer.

Claims (1)

[Claims] 1. Mix a potash compound and an aluminum compound with the crushed material of potash-containing mineral, and then heat this at 800 to 1.300°.
1. A method for producing a slow-release potassium fertilizer, which comprises separating and obtaining a soluble potassium compound after baking with C.