JPH0223514B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a slow-release molten potassium silicate magnesium fertilizer, and its purpose is to have a high content of soluble potassium, soluble magnesium, and pH4 sodium acetate soluble silicic acid, and optionally contain soluble boron. It is an object of the present invention to provide a method for industrially producing a gaseous slow-release fused potassium silicate magnesium fertilizer that can contain. Many proposals have been made regarding slow-release potash fertilizers and their production methods, but all of them focused only on the potash component and vitrified it to make it slow-release. I can't find anything that has been considered. For example, there are (1) Japanese Patent Publication No. 55-37498, (2) Japanese Patent Application Publication No. 51-118672, and (3) Japanese Patent Application Publication No. 129367-1982, but method (1) is generally avoided in the fertilizer industry. However, we disclose a method for producing a special vitreous soluble potash fertilizer that is manufactured by melting and rapidly cooling raw materials with a certain composition range containing medium to high Al ₂ O ₃ components, which is recognized in the glass industry. Method (2) discloses a method for producing an amorphous slow-release potassium fertilizer by melting and decomposing certain raw materials and water-cooling and pulverizing them, and method (3) discloses a method for producing an amorphous slow-release potassium fertilizer made by melting and decomposing certain raw materials and pulverizing them with water cooling. A certain amount of potash composition
A glassy slow-release potash fertilizer containing CaO is disclosed. All of these disclose slow-release potash fertilizers that focus only on the potash component and vitrify it, as well as their production methods. It is not a comprehensive review of the suitability of use. Moreover, all of these require rapid cooling operations in terms of manufacturing methods. Therefore, in view of the above, the present inventors have developed a method for industrially producing slow-release fused potassium silicate magnesia fertilizer from various silicic acid-containing substances, alumina-containing substances, magnesia-containing substances, lime-containing substances, or mixtures thereof and potash compounds. As a result of studying the method, it was found that by heating and melting a mixture of these specific compositions, the object of the present invention could be easily vitrified regardless of the cooling conditions of rapid cooling or gradual cooling, and the present invention was completed. That is, the present invention provides quartzite, silica sand, blast furnace slag, converter slag, nickel slag, stainless steel slag, phosphate slag, ferrophosphor slag, limestone, ferromanganese slag,
Adding a potash compound to one or more of dolomite, quicklime, andesite, combustion ash of grass, wood, garbage, lime, alumina sand, serpentine, and peridotite (a)
Al ₂ O ₃ content is 8% by weight or less, (b)
CaO + MgO + K ₂ O + Al ₂ O ₃ /SiO ₂ molar ratio is 1.0 or more, (c) the molar percentage of SiO ₂ is 50% or less, and (d)
This is a method for producing a slow-release fused potassium silicate fertilizer, which is characterized by mixing CaO + MgO / SiO ₂ so that the molar ratio is 0.5 or more, heating and melting, then cooling and pulverizing. The raw materials of the present invention include silicic acid-containing substances, alumina-containing substances, magnesium-containing substances, lime-containing substances, mixtures thereof, or minerals containing these as main components,
Any sub-raw slag from the iron and non-ferrous metal industries, which is generally known as siliceous fertilizer, can be used, and one or more of the above-mentioned quartzite or peridotite can be used industrially. These are usually pulverized to a diameter of about 0.5 to 60 mm before use. In addition, the potash compounds used in the present invention include one or more potash-containing minerals such as potash carbonate, caustic potash, potash glass, potash feldspar, rhyolite, potash quartz trachyte, sericite, and glauconite. All of these can be used in the form of powder or flakes, and natural products can be used by pulverizing them to an appropriate particle size. Regarding these mixing ratios, (a) the Al ₂ O ₃ content is 8% by weight or less, and (b) the total mixed composition.
The molar ratio of CaO + MgO + K ₂ O + Al ₂ O ₃ /SiO ₂ is 1.0 or more, (c) the molar percentage of SiO ₂ is 50 or less, and (d)
It is necessary to make the CaO+MgO/SiO ₂ molar ratio 0.5 or more. Here, if the Al ₂ O ₃ content exceeds 8% by weight, it will not affect the vitrification of the raw material, but if it is used in combination with phosphoric acid fertilizers, it will tend to fix phosphoric acid. This is not preferable because it not only reduces the effectiveness of the fertilizer, but also reduces the solubility of silicic acid in the pH 4 sodium acetate buffer. or,
As for the lower limit, if the Al ₂ O ₃ content is extremely low, economical operation is difficult, so it must be at least 2% by weight.
is necessary. The evaluation method for soluble silicic acid in glassy fertilizer using pH4 sodium acetate buffer is included in the Ministry of Agriculture, Forestry and Forestry Official Analysis Method for Fertilizers published in 1984 as a method to improve the drawback that the conventional N/2 hydrochloric acid soluble silicic acid does not necessarily match the fertilizer effect. This is a new addition.
This method is a joint experiment between the Ministry of Agriculture, Forestry and Forestry and related industries, as there is an extremely high correlation between the amount of silicic acid that is rapidly absorbed by plants and the amount of silicic acid given as fertilizer (the amount of silicic acid obtained by the shinto extraction method using a pH 4 sodium acetate buffer). It has been recognized as extremely reliable. The present invention was completed as a result of various studies on the mixing ratio of raw materials in order to obtain a slow-release fused potassium silicate magnesia fertilizer with high silicic acid solubility and high potash and magnesium solubility. The CaO + MgO + K ₂ O + Al ₂ O ₃ /SiO ₂ molar ratio, the SiO ₂ molar percentage, and the CaO + MgO / SiO ₂ molar ratio are all based on the potassium and magnesium solubility rate (2% citric acid soluble K ₂ O / total _K2O percentage and 2% citric acid solution soluble
MgO/total MgO ratio) is 90% or more and
Silicic acid solubility rate with pH4 sodium acetate buffer (soluble
SiO ₂ /total SiO ₂ ratio) of 60% or more, which is necessary for industrially easy melting and vitrification regardless of cooling conditions. Preferred values for each are approximately 1.0 to 1.2 for the CaO + MgO + K ₂ O + Al ₂ O ₃ /SiO ₂ molar ratio, and 40 to 50 for the SuO ₂ molar percentage.
% and the CaO+MgO/ _SiO2 molar ratio are about 0.5 to 1.5. If it deviates from the above range, the object of the present invention will not be achieved and economical operation will also become difficult. The F content is preferably 0.3 to 0.8% by weight, as vitrification becomes easier as the amount of F added increases, and the silicic acid content soluble in the pH4 sodium acetate buffer increases, but the soluble potassium content decreases. As the F-containing raw material, phosphate slag or fluorite can be used. In addition, it is more preferable for the slow-release fused potassium silicate fertilizer of the present invention to contain magnesia and boron components in terms of fertilizer effect. When adding a magnesium component, 3 to 10% MgO of peridotite, nickel slag, dolomite, etc. per raw material mixture will efficiently add the target material without reducing the silicic acid solubility in pH 4 sodium acetate buffer. It's appropriate to get it. As for the boron component, it is generally sufficient if it is distributed in a small amount, and if the raw material is insufficient in boron component, boron-containing minerals such as borax and colemanite can be used as appropriate. In the present invention, the above raw material mixture is heated and melted in an electric furnace, open hearth, rotary kiln, or the like. The heating temperature at that time varies depending on the equipment, raw materials, mixing ratio, etc., but usually around 1000 to 1500°C is sufficient.
Further, as for the time, 0.5 to 5 hours is sufficient. Then, by heating and melting, cooling and pulverizing, a slow-release fused potassium silicate magnesia fertilizer can be obtained. Regardless of the cooling conditions, whether rapid cooling (water cooling, air cooling) or slow cooling, one of the features of the present invention is that vitrification is easy and the desired product can be obtained efficiently. Regarding the grinding conditions, in the case of water cooling, the molten raw material is crushed by colliding with a large amount of water flow, and the crushed material is dried and sieved. In that case, the preferred particle size is about 1 to 4 mm in diameter. For air-cooled and slow-cooled materials, the specific surface area is 700~
Grind at 3000cm ² /g until particles of 44μ or less account for about 25 to 60%. Although it is possible to apply the pulverized product as it is, it is also possible to apply liquid binders such as CMC, PVA, alcohol fermentation waste liquid, sodium lignin sulfonate, pulp waste liquid, alkali silicate, or magnesium sulfate, potassium sulfate, potassium chloride, bentonite, etc. It can be granulated to an appropriate size by a conventional method using one or more solid binders. Thus, according to the present invention, it is possible to obtain a slow-acting product with an industrial solubility rate of potash and magnesia of 90% or more, a silicic acid solubility rate of 60% or more with a pH 4 sodium acetate buffer, and a water-soluble potassium content of 3% or less. It has become possible to produce molten potassium silicate magnesium fertilizer. In addition, the fertilizer of the present invention has component values of 20.0% or more of soluble potassium, 25.0% or more of soluble silicic acid, and 3.0% or more of soluble magnesia. Furthermore, the slow-release dissolved potassium silicate magnesium fertilizer obtained by the present invention has a high silicic acid solubility rate in a pH 4 sodium acetate buffer, and thus has resistance to various pests and diseases through early absorption of silicic acid into paddy rice. Increasing sexuality,
It has the effect of preventing flopping and increasing yields, and is also adsorbed to the root surface of all other plants, and its film function provides resistance to insects caused by the snail beetle and root rot. It is also effective in strengthening the Moreover, most of them are sparingly soluble in water, but soluble in weak organic acids, so they do not cause concentration problems due to excessive application of conventional water-soluble potassium fertilizers such as KCl, K ₂ SO ₄ , KNO ₃ , and reduce runoff losses due to rainwater. It has various excellent properties such as no Next, the present invention will be explained in more detail with reference to Examples and Test Examples. Example 1 Total W・K ₂ O 22.0% by weight, Al ₂ O ₃ 6.5% by weight SiO ₂
49 mol%, (CaO + MgO)/SuO ₂ molar ratio:
0.64, (CaO + MgO + Al ₂ O ₃ + K ₂ O) / SiO ₂ molar ratio: 1.04, 70 kg of quartzite, 90 kg of blast furnace slag, 100 kg of nickel slag, 85 kg of phosphorus slag, 70 kg of andesite,
160 kg of potassium carbonate and 1 kg of colemanite were mixed and melted in an open resistance furnace with an inner diameter of 1.5 mφ and 640 KVA, and after confirming that almost the entire amount was melted, the mixture was tapped. Pressurized water is injected onto the hot water to quickly cool and crush the water and the hot water from the taphole is poured into a stainless steel ladle with an inner diameter of 20cmφ and a depth of 30cm for about 8 minutes (approx. 15Kg).
We then prototyped a slowly cooled product by leaving it to cool in the air. As a result of X-ray diffraction, both the granulated product and the slowly cooled product were found to be amorphous, and their characteristic values were almost the same. For granulated products, the granulated product is dried at 107℃, crushed to a Blaine value of 1500 to 2000 cm ² /g, -44 μ30 to 50%, and then adjusted to the inner diameter using a designated binder.
Pelletize to approximately 3mmφ using a 50cmφ dish-shaped granulator and heat to 107℃.
It was dried. At this time, the yield rate of 1 to 4 mm is 72 to 80.
%, the compressive strength for diameters of 1 to 4 mm was 1 to 3 Kg/grain. Other results are shown in Table 1. Note that the raw material blending ratio in Table 1 is expressed based on the total amount of 100 kg. Examples 2 to 8 Various slow-release fused potassium silicate magnesia fertilizers were produced in the same manner as in Example 1 using various raw materials. The manufacturing conditions and results at that time are summarized in Table 1. Comparative Examples 1 to 3 When slow-release dissolved potassium silicate magnesia fertilizer was produced in the same manner as in Example 1 outside the range of the raw material blending ratio of the present invention, the silicic acid solubility of the product in a sodium acetate buffer solution of pH 4 was It turned out to be extremely bad. The manufacturing conditions and results are summarized in Table 1.

【table】

【table】

[Table] Test Example Fertilizer efficacy tests were conducted using the slow-release fused potassium silicate magnesium fertilizer obtained in Example 1 under conditions 1 to 6 below, and the following results were obtained. Effects of granular fused potassium silicate magne soil fertilizer 1 Crop Paddy rice Toyonishiki 2 Location 3 Matsuki-cho, Gunyama City, Fukushima Prefecture Scale 3 A/5000 Wagner pots 4 Test soil Volcanic ash soil, Ishikawa-cho, Fukushima Prefecture 5 Cultivation method Seedlings on May 13th Transplanting 2 plants per pot with 2 plants per pot. Composition of 6 districts.

【table】 7 Fertilizer efficacy test results 7.1 Growth and yield Shown as the average value of three replicates

【table】 7.2 Nutrient absorption

【table】

[Table] From these results, we were able to prove how the dissolved potassium silicate magnesium fertilizer of the present invention is more effective in absorbing nutrients and increases the yield compared to water-soluble potassium fertilizers. Among them, especially K ₂ O,
It was about 1.8 to 2.2 times more effective in absorbing MgO and SiO ₂ and is thought to be useful for promoting rice growth.

Claims (1)

[Scope of Claims] 1. Quartzite, silica sand, blast furnace slag, converter slag, nickel slag, stainless steel slag, phosphate slag, ferrophosphor slag, ferromanganese slag, limestone, dolomite, quicklime, andesite, grass, wood, garbage, coal. Potassium compound is added to one or more of combustion ash, alumina sand, serpentine, and peridotite, (a) Al ₂ O ₃ content is 8% by weight or less, (b) CaO + MgO + K ₂ O + Al ₂ O ₃ /SiO ₂ (c) the molar percentage of SiO ₂ is 50% or less, and (d) the molar ratio of CaO + MgO / SiO ₂ is 0.5 or more, then heated and melted, then cooled and pulverized. A method for producing a slow-release fused potassium silicate magnesia fertilizer.