JPS59152219A - Production of granular slaked lime - Google Patents

Abstract

PURPOSE:To produce granular slaked lime having excellent handleability and disintegrable easily in water, by adding a granulation agent containing an organic material to slaked lime, kneading the mixture under high pressure, extruding and granulating at low pressure, and drying in a static state. CONSTITUTION:A proper amount of a granulation agent containing an organic material is added to slaked lime, and kneaded under a high pressure (about 25- 70kg/cm<2>) in a kneader to impregnate the slaked lime sufficiently with the granulation agent and to cover the fine particle of the slaked lime with the agent. The kneaded slaked lime is extrusion-molded through a die with a blade- type extrusion granular, etc. under a low pressure (about 10kg/cm<2>) to prevent the exudation of the granulation agent from the space between the fine particles of slaked lime. The granulated slaked lime is dried in a static state keeping the granules from agglomeration and sintering by rolling, etc., to obtain granular slaked lime. Concentrated waste liquid of Steffen process, concentrated liquid of alcohol fermentation waste, solution of lignin sulfonic acid salt, etc. can be used as the organic material in the granulation agent.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing granular slaked lime.

Because it is in powder form, it is difficult to handle, and mechanical spraying in strong winds reduces the spraying effect.

Conventionally, methods of compressing slaked lime and granulating it, or adding water to granulate it, and Steffen wastewater concentrate C or less (
It is called Of'lF1. ) and alcohol fermentation waste liquid concentrate (hereinafter referred to as r00T') SJ. ) has been proposed to prevent scattering.

However, in the case of granulation of the former, it is difficult to disintegrate and dissolve in water, and the reaction rate against weak acids is also low, so that the original function of agricultural slaked lime cannot be fully demonstrated. . Next, in the latter scattering prevention method, 08F or oons are added to slaked lime, and the powder is deposited on the surface of the additive by simply kneading and kneading. The amount of addition and crosstalk time vary depending on the concentration, temperature, etc., and a skilled manufacturing technique is required.

In addition, the additives (C8F, Co5t) in the product are extremely hygroscopic, so careful storage management is required under humid weather conditions, and there are also disadvantages such as caking in the spraying machine when spraying. It is occurring.

Other attempts have been made to add additives to slaked lime and granulate it by compression or extrusion, but this has not been successful.

The present invention was developed in view of the above-mentioned circumstances, and it is easy to blow and handle slaked lime and is suitable for mechanical spraying. The object of the present invention is to provide a method that can form granules so as to fully exhibit the harmonization effect.

In the present invention, slaked lime refers to those based on the Fertilizer Control Law, that is, those obtained by digesting oxidized lime (quicklime) (calcium hydroxide), -lomite calcined (magnesium carbonate,
Calcium) Digested from K (magnesium hydroxide) and mixtures thereof are also referred to as the same name.

The present invention involves a kneading process in which a granulating agent containing an organic substance such as O8F', 00r)8 or lignin sulfonate solution is added to slaked lime and kneaded under high pressure, and the kneaded slaked lime is mixed under low pressure. It consists of an extrusion granulation step of extrusion granulation and a drying step of statically drying the extrusion granulated slaked lime.

Typical granulating agents containing organic substances used in the present invention are cans from a sugar beet factory using the Steffen process, cans from a 08F1 alcohol factory, and a lignin sulfonate solution obtained from a paper factory, both of which have a water content of 20
~80°C can be used, but other organic containing effluents with similar viscosities and surface tensions to those mentioned above can also be used.

Next, each process will be explained in order.

First, put slaked lime into the kneader for kneading, and add 08
Granulating agents containing organic substances such as F (hereinafter referred to as "granulating agents")
) is added. The ratio of the two differs depending on the type of granulating agent and the amount of water in it, but for example, if the moisture content of the granulating agent is 50 g, the granulating agent is about 15 to 20 g (weight ratio) of slaked lime, especially 17 g. Preferably around 1000 yen. It is possible to use the above-mentioned granulating agent with a water content in the range of 20 to 80 mo, but the amount added to the slaked lime should be increased or decreased depending on the water content, taking the above values into consideration.

The slaked lime and granulating agent are subjected to a kneading process under high pressure in a kneader. Here, kneading refers to kneading enough to uniformly expose the surface of the slaked lime fine particles to the granulating agent. Although the pressure in this step varies depending on the state of the granulating agent, it is appropriately carried out within the range of 25 to 70 kt/i. When this step is carried out in the kneader, the granulating agent sufficiently penetrates into the slaked lime, and each fine particle of slaked lime is covered with a coating of the granulating agent. They attach to each other and become Kiyoshu. The degree of this is such that when you pick it up and squeeze it, it becomes block-shaped.

Next, an extrusion granulation step is performed in which the slaked lime that has undergone the above-mentioned kneading step is extruded and molded under low pressure using an extrusion granulator, for example, a play type extrusion granulator.

The extrusion granulator uses blades to uniformly disperse the supplied slaked lime, and the extrusion blades apply a pressure such as 101 w/i that the granulating agent between each fine particle of slaked lime does not come out.
Extrusion molding is carried out at a moderate pressure through a screen having 2 to 3 die holes.

Extrusion granulated slaked lime varies depending on the thickness of the screen, but has a length of 1 to 3 fins. The internal structure of extrusion-granulated slaked lime is different from that of extrusion-granulated lime under high pressure, in that a granulating agent exists between each fine particle.

Finally, the slaked lime obtained in the above granulation step is sufficiently dried in a drying step. In this step, in order to maintain the shape of the slaked lime obtained in the previous step, it is dried as is.

That is, drying is carried out in a static state to prevent grains from rolling and adhering to each other or solidifying and developing in grain size due to stirring, transfer, etc. If consideration is given to providing continuity between each process and improving work efficiency, a flow dryer is preferable. The drying time of the drying process is appropriately determined depending on the amount of moisture contained in the granulating agent used, but if rapid disintegration in water is required, the residual moisture may be 0.
．． A value of about 3 to 0.5 is desirable.

In this way, the granulated slaked lime obtained by adding a granulating agent to slaked lime, sequentially undergoing a kneading process, an extrusion granulation process, and one culm drying process, has an internal structure with h
11G says to create a space to make it easier to absorb moisture.
can easily collapse. It is strong enough to be handled in handbags, etc., and is easy to handle. Spreading in Okaba etc. does not cause scattering, and after spreading, it absorbs moisture in the soil through the hygroscopic granulation agent and dissolves quickly. , it showed a quick response to acids.

Examples and their test results will be shown below while comparing them with conventional ones. The granulating agent used in each example has the following components and viscosity.

7- Example 1 8.3 kg of agricultural slaked lime was mixed with water of approximately 50 parts (38 kg).
Add F1.7q and knead in a kneader. The pressure during kneading is approximately 40kll/IIJ! It is. Kneading time is 10
The time was 12 minutes, and spike-shaped slaked lime with a water content of 8.5% was obtained. For the granulation process, an extrusion granulator with blades for uniform dispersion is used, and the extrusion blades extrude at a low pressure of 10 kp/i. The proverbial granules can be obtained. By removing excess moisture from this in a flow dryer, the structural surface of the slaked lime was coated with organic matter, and a product having voids tJ in the internal structure of the granules could be obtained. This product was used as prototype 1 and was subjected to physical property and chemical analysis.

Example 2 Using the same method as in Example 1, agricultural slaked lime 8. 00D 81.7ky with a water content of about 50 t was added to 3 m2, followed by pressure kneading, extrusion granulation, and drying to obtain a product.

The shape of this product is the same as in Example 1, and prototype 2
It was used for physical property and chemical analysis.

81 Example 3゜By the same method as in Example 1, a water-based 501 glue dasulfonate solution was added to 8.3 yen of agricultural slaked lime, followed by pressure kneading, extrusion granulation, and drying. Got the product. The shape of this product was the same as in Example 1, and it was used as a prototype 3 for physical property and chemical analysis.

Test results 1゜Prototypes obtained in Examples 1.2 and 3']
, 2 and 3, the results of physical property tests and chemical analyzes are shown in Table 2 A and B, respectively, in comparison with products obtained by conventional methods (indicated as "conventional products"). However, the conventional product was obtained by the following method, which was also used in the following tests, by adding water to industrial slaked lime to bring the water content to approximately 3 degrees. Mix with a nozzle mixer, and then use a nozzle type granulator (45° inclination).
granulated for about 10 minutes, and then granulated with rho lamb silyer (
Granules of slaked lime were obtained by drying in 20 minutes at a burner temperature of 680° C. and a rotation speed of 5 rpm.

This experiment was carried out using a general manufacturing method in which slaked lime was granulated with water and dried.In a moisture-containing situation, the amount of carbon dioxide gas generated from the nose was approximately 18 cm, and this product was The surface was carbonated in 20 minutes to form a spherical granulated product. The crosstalk pressure in the nozzle P lum mixer is 0.2~03
This is a cross-wire method that requires very little pressure between positive and negative signals.

Test results 2 Prototype 1.2.3 and the conventional product, the raw material slaked lime, and the target carbonate lime.The amount of carbon dioxide adsorbed by the prototype during the manufacturing process or while it was left indoors was measured. This is the result.

The prototype and slaked lime were left indoors for 24 hours and 60 days after obtaining the product, and the slaked lime was used as a powder in a granular product with a particle size of 1 to 2 square meters.

Carbonic acid was determined by increasing the amount of potash bulbs and measuring carbonate by decreasing the amount of carbonate on ignition. The results are shown in Table 3.

Table 3 Test result 3゜ This test example determined the reactivity to weak acids.

Prototype 1.2.3 and the conventional product were left indoors for 60 days after production, and then classified and sorted, and 159 of water was added to material 159 with a particle size in the range of 1 to 2 m, and the mixture was stirred with a stirrer. The amount of sulfuric acid added dropwise was adjusted to maintain the pH of the sample in the beaker at 3, and the reaction rate was determined from the amount added. This is shown in Figure 1.

[Brief explanation of the drawing]

Figure wC1 shows the reactivity with dilute sulfuric acid according to Test Results 3. Patent applicant Kunikofu Lime Industry Co., Ltd.

Claims (1)

[Claims] C1) A kneading step in which a granulating agent containing an organic substance is added to slaked lime and kneaded under high pressure, an extrusion granulation step in which the kneaded slaked lime is subjected to low pressure, and extrusion granulation. A method for producing granular slaked lime, which comprises sequentially performing a drying step of statically drying the hydrated slaked lime. (2) The method for producing granular slaked lime according to claim (1), wherein the granulating agent containing an organic substance is a Steffen wastewater concentrate. (3) The method for producing granular slaked lime according to claim (1), wherein the granulating agent containing organic matter is an alcohol fermentation waste liquid concentrate. (4) The method for producing granular slaked lime according to claim 1, wherein the granulating agent containing an organic substance is a lignin sulfonate solution.