JPH0236559B2 - KANKOSEIKEISANHIRYONOSEIZOHOHO - Google Patents

Description

[Detailed description of the invention]

(Technical field) The present invention produces soluble (hydrochloric acid soluble) and citric acid soluble Ca ₂ SiO from rice husk or rice husk ash, dolomite, potassium compounds, iron oxide, and other auxiliary raw materials as necessary. ₄ , _{Fe2SiO4 ,}
The present invention relates to a method for producing a slow-release silicate fertilizer containing K ₂ CaSiO ₄ , K ₂ MgSiO ₄ , etc. as main components. (Prior Art and its Problems) It has been demonstrated that silicic acid fertilizers have a remarkable effect on crops containing a large amount of silicic acid, such as rice and wheat. In addition, even if silicic acid is not directly absorbed by crops, it is known that by applying it to the soil, it can reduce the harm caused by activated aluminum, increase cation exchange capacity, and prevent nutrient runoff. There is. In the past, various studies have been conducted on manufacturing methods for slow-release silicate fertilizers (usually slow-release potassium silicate fertilizers), but none of these methods use aluminum-containing slag, fly ash generated from thermal power plants, etc. The raw material for silicic acid is industrial waste or natural minerals such as potassium feldspar. Aluminum contained in these silicic acid raw materials (see Table 1) constitutes the main component in soil together with silicic acid, and is also taken up into plants in large quantities, but in plants it is absorbed into roots. Most of it is deposited, causing inactivation of phosphorus and inhibition of absorption of calcium and magnesium. Therefore, with the exception of certain acidophilic or acid-resistant plants such as tea plants, its toxicity is considered important and is considered to be a cause of acid damage to plants, and it is considered a harmful element for general vegetation. be. Therefore, in order to produce a fertilizer that does not contain aluminum or has a very small amount of aluminum, it is necessary to use raw materials that do not contain aluminum or have a very small amount of aluminum.

[Table] (Problem of the Invention) An object of the present invention is to provide a method for producing a slow-release silicic acid fertilizer that does not contain aluminum. (Means for Solving the Problems) Therefore, as a result of conducting various studies in order to solve the above problems, the present inventors discovered that rice husks and rice husks, which are generated in large quantities from rice cultivation areas that contain almost no aluminum, which is harmful to vegetation, have been found. A granular mixture is prepared using ash, dolomite, potassium compounds, and iron oxide as necessary as raw materials, and then calcined at a temperature of 900 to 950°C to remove the silicic acid component in the rice husk or rice husk ash, and the silicic acid component in the dolomite. Calcium component, magnesium component,
The inventors have discovered that the above-mentioned problems can be solved by reacting a potassium compound and iron oxide, and have completed the present invention. That is, according to the present invention, rice husk or rice husk ash that does not contain aluminum is used as a silicic acid raw material, and dolomite, a potassium compound, and if necessary iron oxide are added to this silicic acid raw material, and a liquid binder is further added. After kneading, granulating, and drying, it is fired in a fluidized furnace to remove the silicic acid component in the rice husk or rice husk ash.
A method for producing a slow-release silicate fertilizer is provided, which comprises reacting calcium and magnesium components in dolomite, a potassium compound, and iron oxide added as needed. In the method of the present invention, as the silicic acid raw material,
Use rice husk or rice husk ash. As can be seen from Table 2 below, this silicic acid raw material contains a silica component as a main component and does not contain an aluminum component. To carry out the present invention, first, dolomite, a potassium compound, and iron oxide are added as necessary to this silicic acid raw material, and a liquid binder is further added, kneaded, granulated, dried, and granulated and mixed. form.
In this case, potassium carbonate, potassium hydroxide, etc. are used as the potassium compound. As the liquid binder, in addition to waste molasses, an aqueous solution of a water-soluble polymer such as starch, polyvinyl alcohol, or sodium alginate is used. The granulated mixture obtained as described above is then calcined at a high temperature, preferably at a temperature of 900-950°C. By this firing, the silicic acid component in the rice husk or rice husk ash,
Calcium and magnesium components, potassium oxides, and iron oxides in dolomite react to form silicate compounds such as Ca ₂ SiO ₄ , Fe ₂ SiO ₄ ,
A silicic acid fertilizer containing K ₂ CaSiO ₄ and K ₂ MgSIO ₄ as main components is obtained. (Effects of the Invention) The silicate fertilizer of the present invention, unlike conventional silicate fertilizers, does not substantially contain aluminum components harmful to vegetation, and does not cause harm to aluminum. Furthermore, this silicate fertilizer has slow-release properties, and is dissolved by weak acids secreted by plants from their roots and absorbed by plants. (Example) Next, examples and comparative examples of the present invention are given,
I will explain in detail. The chemical compositions of rice husk, rice husk ash, and dolomite used as raw materials are shown in Table 2. Further, the properties of the slow-release silicate fertilizers trial-produced in each example are shown in Tables 4 and 5, and the properties of the baked product trial-produced in the comparative example are shown in Table 6.

[Table] Examples 1 to 3 Potassium carbonate aqueous solution and 50% blackstrap molasses aqueous solution were added to rice husks and dolomite crushed into 200 meshes, kneaded, granulated, dried, and separated through a sieve to obtain particles with a particle size of 1 to 1. A 2 mm one was used in the experiment. Blackstrap molasses was used as a binder for granulation. The composition of the granules is: SiO ₂ : 34.3wt%, CaO: 29.2wt%
%, MgO: 17.0wt%, K ₂ O: 19.5wt%, (CaO+
MgO+K ₂ O)/SiO molar ratio: 2. This granulated material was heated in a batch-type fluidized furnace under the following conditions: firing temperature: around 930°C, firing time: 20 minutes (Example 1), 40 minutes (Example 2), and 60 minutes (Example 3). Slow-release silicic acid fertilizer was obtained by calcination. The fluidized fluidized furnace used for firing was the batch type fluidized furnace shown in Figure 1, with an inner diameter of 100 mm and an aperture ratio of the dispersion plate: 1.4.
%, and the height of the fluidized stationary bed of the granulated product prepared to have a particle size of 1 to 2 mm is approximately 300 mm. Air is used as the fluidizing gas,
The flow rate was controlled by a flow meter. The analysis of soluble silicic acid (amount eluted with 0.5N hydrochloric acid), soluble potash (amount eluted with 2% citric acid), etc. of the fired product was all based on the official fertilizer analysis method. Examples 4 to 6 Rice husk ash having the composition shown in Table 2 was used as a silicic acid raw material, and the components of the granules were SiO ₂ :34.1wt%, CaO:
29.2wt%, MgO: 17.0wt%, _K2O : 20.0wt%,
The experiment was conducted in the same manner as in Example 1, except that the molar ratio of (CaO+MgO+K ₂ O)/SiO ₂ was adjusted to 2. Examples 7 to 9 In Examples 1 to 6, _SiO2 -CaO-MgO- _K2O
However, in Examples 7 to 9, SiO ₂ -CaO-MgO-K ₂ O-Fe ₂ O ₃ in which iron oxide was added to the above four components was shown. 5
The raw materials were adjusted to the component system. That is, to rice husk, dolomite, and iron oxide that have been crushed into 200 meshes, an aqueous potassium carbonate solution and a 50% aqueous solution of blackstrap molasses are added, kneaded, granulated, dried, and separated through a sieve to obtain particles with a particle size of 1 to 1.
A 2 mm one was used in the experiment. Blackstrap molasses was used as a binder for granulation. The ingredients of the granules are
_SiO2 : 32.7wt%, CaO: 24.8wt%, MgO:
14.5wt% _{, K2O} : 19.3wt%, _Fe2O3 : 9.7wt%,
(CaO+MgO+ _K2O + _Fe2O3 )/ _SiO2 molar _ratio : 2
It is. Next, this granulated material was heated for 30 minutes (Example 7).
The experiment was conducted in the same manner as in Example 1, except that the firing time was 40 minutes (Example 8) and 60 minutes (Example 9), and slow-release silicate fertilizers were obtained. Comparative Examples 1 to 3 Silicic acid and dolomite in rice husks crushed into 200 meshes were mixed in the proportions shown in Table 3, and then this mixture was heated to 900°C using an electric furnace.
60 minutes at 1100℃ for comparative example 2, and 60 minutes at 1100℃ for comparative example 3.
It was fired at 1100°C for 300 minutes, and the resulting fired product was evaluated in the same manner as in each example.

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[Table] 〓Possible in fertilizer〓

Claims (1)

[Claims] 1 Rice husk or rice husk ash that does not contain aluminum is used as a silicic acid raw material, and dolomite, a potassium compound, and iron oxide as necessary are added to this silicic acid raw material, and a liquid binder is further added, kneaded, and granulated. After drying, it is fired in a fluidized furnace to react the silicic acid component in the rice husk or rice husk ash, the calcium component and magnesium component in the dolomite, the potassium compound, and the iron oxide added as necessary. A method for producing a slow-release silicate fertilizer characterized by: