JPS59156990A - Manufacture of granular polycal fertilizer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a granular polycal fertilizer which, when applied to a field as a granular fertilizer, disintegrates and becomes powder due to moisture in an earthen wall.

When plants grow, they absorb nutrients through their roots. At that time, plants produce acid from their roots to take in the ingredients in the soil. It is well known that when crops are grown in a field, the soil gradually becomes acidic, making it difficult to grow crops. For this reason, calcareous fertilizers have been used for a long time, and one of them is the polycal fertilizer made from converter slag (the granular fertilizer of the present invention).
There is a type of sandy polycal fertilizer (hereinafter referred to as sandy polycal fertilizer) to distinguish it from polycal fertilizer. The ingredients of sandy polycal fertilizer are as shown in Table 1. Note that this compressed powder component is the same for both powdered polycal fertilizer and granular polycal fertilizer.

Table-1 Sand-like polycal fertilizer ingredients (%) Sand-like polycal fertilizer is a type of mineral fertilizer.

Generally, mineral fertilizers have the property of being difficult to dissolve in water. The grain size of mineral fertilizers currently used is 2000.
The size of the fertilizer is still less than 1.680 mm (sandy), but it goes without saying that the effect of the fertilizer will be even greater if it is made into finer powder fertilizer. But 2. @ When spraying in the air or on windy days, it scatters, making it difficult to spray on the target fields, and the negative effects on the human body cannot be ignored, so it is recommended to simply make the particle size finer. It's not a thing.

For this reason, calcical fertilizer made from blast furnace slag, which is a type of mineral fertilizer similar to sandy polycal fertilizer, is: - However, it is pulverized into pellets of several mm in diameter using a pelletizer, and is not water-containing. Products that disintegrate into powder when exposed to water have become commercially available.

However, unlike sandy or powdered silicic fertilizers, sandy or powdered silicic fertilizers have a high content of lime, which is resistant to 2 reactions, so they have the property of hardening like cement if left with water. . In order to granulate a powder, an appropriate amount of water must be added, so sandy or powdered polycal fertilizers will solidify when water is added and granulated.

There was a drawback that the powder effect could not be obtained.

The present invention has been made to eliminate this drawback.

This is a method for producing granular polycal fertilizer that disintegrates into powder due to moisture in the soil.

The mineral phase in converter slag is 3Cao-8lo2゜2
Cao ” S 102 r 2 Cao ” F
Typical examples include e20s r Cao+ Ca (OH)2, among which 8CaO-3+Q2 + 2 CaO Fist S+02 is known as a cement mineral.
It has the property of causing a hydration reaction and solidifying when water is present together with CaO etc. It also has the property of causing a carbonation reaction with carbon dioxide gas in the air and becoming the same size. When powdered slag is granulated using a pelletizer, the reason why it does not become pulverized even after it is put into water is due to the hydration reaction of the lime.
This is due to carbonation reaction.

Therefore, 3CaO5iO6l is exposed on the powder particle surface in advance to prevent the pellet from chemically solidifying.
If 2CaO@5iO21Cab, Ca(OH)2, etc. are changed to poorly soluble calcium salts, even if they are physically granulated, there is no caking substance on the surface of the powder particles, so they disintegrate with moisture and become powder. It is.

One method of the present invention is to carbonate the surface of powdered converter slag particles with carbon dioxide gas, and the solubility of calcium carbonate produced at this time is 0.0149/100 mA at 25°C.
It is poorly soluble. In addition, there are methods of producing poorly soluble calcium salts by phosphate conversion, oxalate conversion, tartrate conversion, etc. Table 2 shows the solubility of these salts in water.

Therefore, the converter slag is pulverized to 150p or less.

Carbonic acid, phosphoric acid, carbon dioxide, tartar. acid or table-
Solubility of 2 Calcium Salts Add these salts in the proportions shown in Table 3.

To provide a method for producing a granular polycal fertilizer, in which the surface of powdered converter slag particles is inactivated as potassium carbonate, calcium phosphate, calcium oxalate, or tartaric acid, respectively, and then granulated with a pelletizer.

Table 3: Additives and easily soluble calcium salts dissolve the surface of powdered converter slag particles during treatment, and add new 3cao-81o2゜2.
CaO-8iO2, Cab, and Ca(OH)2 are exposed, and the treatment is not limited to the surface of the particles. Therefore, the entire amount of calcium in the powdered converter slag component must be treated, and the fertilizer effect is lost.

Next, embodiments of the present invention will be described.

Example Converter slag was crushed to 150 μm or less [water was added while stirring, and the slag was subjected to various treatment methods and pulverization rates as shown in Table 4, and then dehydrated. 2-4 with pelletizer
A granular polycal fertilizer of amφ was produced. Table 4 shows the in-water pulverization rate of each after drying. (According to the granular calcic fertilizer standards, this is 80% or more.) As is clear from the above examples, only the lime content on the surface of the powdered converter slag particles is converted to the slightly soluble calcium salts mentioned above. By pre-treating the fertilizer, it is possible to disintegrate and pulverize it again when it contains moisture without damaging the fertilizer components, and it is possible to obtain the fertilizer effect. Such a method can also be used to produce granular fertilizers containing calcareous material.

Patent applicant: Kawatetsu Mining Co., Ltd.

Claims (1)

[Claims] In the method of producing granular polycal fertilizer using powdered converter slag as raw material, before granulating powdered converter slag, the powdered converter slag is brought into a wet or slurry state, and an acid or salt is added to form a hardly soluble calcium salt. A method for producing a granular polycal fertilizer, which comprises inactivating the calcilum content on the surface of the powder particles.