JPS5912626B2 - Method for producing slow-release potassium fertilizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides 20.Al2O which is soluble in potassium-containing minerals.
The present invention relates to a method for producing a slow-release potash fertilizer containing 3.2SiO2, 20.CaO-8iO2, or 20.MgO-8i02 as main components.

The main components of potassium-containing minerals are K2O, Al2O3, 6Si
02, and the obtained by processing this is 20.Al2O
Since 3.2Si02 is insoluble and soluble in water, it is known to be used as a slow-release potash fertilizer.

In addition, the potassium fertilizer obtained by the present invention contains 20
・CaO-8iO2, ni20.MgO.5i02 is also known to be soluble and useful as a slow-release potassium fertilizer.

Conventionally, by mixing potash-containing minerals and basic potassium compounds and firing the mixture, soluble 20.Al2
Various methods for manufacturing O3.2Si02 have been proposed (for example, Japanese Patent Publication No. 38-17394, No. 38-173).
No. 95, No. 43-78.16).

However, in these conventional methods, even if the reaction is sufficiently carried out, the amount of water-soluble potassium (K2) is about twice that of water-soluble potassium.
O-nSi02. n represents 2 or 4.

(hereinafter the same applies) is produced as a by-product, which not only has the disadvantage of an extremely low yield, but also has the following disadvantages.

(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, if a basic potassium compound and a calcium and/or magnesium-containing compound are mixed with a potassium-containing mineral and then calcined at 800 to 1,300°C,
All the drawbacks of conventional methods can be improved,
extremely economically from potash-containing minerals.
2SiO2, ni20・CaO・SiO2 or ni2(
) It was discovered that a slow-release potash fertilizer containing MgO-8i02 as a main component could be produced, and the present invention was completed.

Any mineral containing potassium, such as potassium feldspar, potassium quartz trachyte, sericite, and glauconite, is useful as the potassium-containing mineral used in the present invention, and these minerals are crushed to about a 100-inch mesh. It is best to use it as

In addition, basic potassium compounds include K2COa, KO
Examples of calcium- and/or magnesium-containing compounds include dolomite, dolomite clinker dust, magnesia lime, limestone,
Any compound containing calcium, magnesium, or both, such as calcium carbonate, quicklime, slaked lime, magnesium calcium carbonate, magnesium hydroxide, magnesium oxide, serpentinite, magnesite, and slagite, is useful, and these bases The potassium compound and the compound containing calcium and/or magnesium may also be used after being pulverized to about 100 inch mesh, or may be used in the form of an aqueous solution.

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 0.3 to 1.5, more preferably 0.2 (molar ratio).
4 to 1.0, and (CaO+Mg0)/5
A basic potassium compound and a calcium and/or magnesium-containing compound are mixed with the potassium-containing mineral so that the iO2 (molar ratio) is 0.4 to 1.5, more preferably 0.5 to 1.0. good.

Next, the mixture obtained in this way was
℃ for 0.5 to 4 hours in an electric furnace or rotary kiln, and the resulting fired product is cooled, pulverized, washed with water, filtered, and dried to form a resolubilized 20.Al2O3.
・2SiO2 and 20・Ca (ISi02 or 20・MgO・5i02, etc.) are obtained as slow-release potassium fertilizer.

In the present invention, in addition to the basic potassium compound, calcium and/or magnesium-containing compounds are mixed in advance with the potassium-containing mineral, so in the conventional method, water-soluble potassium compounds (K2O・n5i02
), it is possible to produce a slow-release potassium fertilizer with an extremely high slow-release potash content relative to total potash compared to conventional methods, and at a high yield.

Furthermore, since only a small amount of water-soluble potassium compounds are produced as a by-product during the firing process, all the drawbacks of conventional methods can be overcome.

In other words, the fired product does not adhere to the walls of the firing furnace (it is extremely easy to wash and filter the fired product with water, and there is no bubbling caused by water vapor and gas generated during firing, so there is no reduction in the reaction rate. Volatilization of potash is also extremely low.

Furthermore, the slow-release potassium fertilizer obtained by the present invention also contains Ca or Mg, which are essential elements for plant growth, and has a high content of fertilizing ingredients.

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 trial-manufactured by each side.

The potassium-containing minerals used on each side were pulverized 100-inch meshes of potassium quartz trachyte produced in the Yamaguchi region and potassium feldspar produced in Fukuoka Prefecture, having the chemical composition shown in Table 1.

Example 1 39.2 kg of a 48 wt% KOH aqueous solution was added to potassium quartz trachyte 20.0 to 9 (K20/5i02 (molar ratio) = 0
．． 85) and dolomite clinker dust (main component; Ca047.8w) crushed throughout the 100-inch mesh.
t%, Mg024.3 wt%) to 12.3
ky ((CaO+MgO)/SiOz (molar ratio)=0.8) and fired in a rotary kiln at 1,000°C for 1.5 hours.

After cooling and pulverizing the obtained baked product, water 201 was added and stirred for 10 minutes, washed with water, further filtered and dried to obtain 45.2 kg of slow-release potash fertilizer.

Example 2 The amount of 48 wt % KOH aqueous solution used was 15.6
kg (K20/5i02 (molar ratio) = 0.4.1, but the experiment was conducted in the same manner as in Example 1.

Example 3 The amount of dolomite clinker dust used was 9.2 kg (
(CaO+Mg0)/5i02 (molar ratio) = 0.6
．． 〇Example 4 Potassium quartz trachyte 10.The experiment was conducted in the same manner as in Example 1 except that :] 2CO3 and dolomite (main component; C
a033.6 wt%, Mg018.9 wt%) each, 11.58 kg each, 8.34 to 9 (K20/S
102 (molar ratio) = 0.85), (CaO+
Mg0)/S 1o2 (molar ratio) = O, S) mixed, 1
,000°C for 1 hour in an electric furnace.

After this, the experiment was conducted using the same treatment as in Example 1.

Example 5 To 10.0 kg of potassium feldspar, 8.5 kg each of 2CO3 and CaCO3 crushed to a 100-inch mesh were added.
, 4 kg (K20/5iO2 (molar ratio) = 0.7.
CaO/S10□ (molar ratio) 20, 7] mixed, 1,2
It was fired in an electric furnace at 00°C for 1 hour.

After this, the experiment was carried out in the same manner as in Example 1. Example 6 Instead of Ca COs, 3.4 kg of MgO (MgO/5i02 (molar ratio)
The experiment was conducted in the same manner as in Example 5, except that −0, 8, and 1 were used.

Comparative Example 1 An experiment was conducted in the same manner as in Example 1 except that dolomite clinker dust was not mixed. Comparative Example 2 An experiment was conducted in the same manner as in Example 4 except that dolomite was not mixed. We conducted an experiment.

Comparative Example 3 An experiment was conducted in the same manner as in Example 2, except that the firing temperature was changed to 700°C.

Comparative Example 4 An experiment was conducted in the same manner as in Example 2, except that the firing temperature was changed to 1400°C.

In addition, according to the present invention, even when using potash-containing minerals, basic potassium compounds, or calcium- and/or magnesium-containing compounds that are targeted by the present invention listed above other than those used in each example, each From the experimental results of 0 or more in which almost the same results as those in the examples were obtained, it was found that according to the present invention, it is possible to produce a fertilizer with an extremely high slow-release potash content that lasts all months and at a high yield. It is recognized that the present invention is industrially extremely superior.

Claims (1)

[Claims] 1. Mixing a basic potassium compound and a calcium- and/or magnesium-containing compound with a potassium-containing mineral,
A method for producing a slow-release potash fertilizer, which is then fired at a temperature of 800 to 1,300°C.