JP2587865B2 - Method for digesting soft-burned part of quicklime powder for lightweight cellular concrete - Google Patents

Description

The present invention relates to a method for producing quicklime powder for lightweight cellular concrete (hereinafter referred to as ALC).

[Conventional technology]

In general, the quality of quick lime for an ALC raw material is required to have high CaO purity and a slow reaction upon contact with water. The reactivity as a quality characteristic of quicklime has a close relation with the limestone firing conditions in producing quicklime. That is, quicklime obtained by calcining limestone at a low temperature for a short time is called a soft-baked product, and has a rapid reaction with water, and quicklime obtained by burning limestone at a high temperature for a long time is a soft-baked product. The reaction with water is slow. That is, the soft-baked product is
Calcareous raw materials such as cement, which are other raw materials,
When mixed with siliceous raw materials such as silica sand silica, aluminum powder, water and chemicals to form a slurry, a rapid digestion reaction occurs, generating heat and rapidly removing a large amount of water, necessary for foam formation during the foaming process Loss of fluidity, thereby causing troubles such as disorder of the bubble shape and collapse after foaming. Further, it prevents sufficient dispersion of the quicklime particles, forms unreacted quicklime agglomerated parts, causes a loss of raw materials, and contributes to a reduction in product quality.

On the other hand, with the conventional lime burning technique, it is extremely difficult to produce quicklime composed only of soft-baked portions that do not include soft-baked portions. Therefore, if the soft-burned part causing the above-mentioned trouble is digested with water in advance and slaked and calcified, there is no rapid heat generation when reacting with water, and water is not rapidly lost. Good dispersibility of particles,
No unreacted condensed parts are formed. As described above, partial digestion of quicklime powder is an effective means for obtaining quicklime as an ALC raw material, and the following methods are known.

(1) A method of spraying water or a grinding aid, for example, a surfactant diluting solution, onto the quicklime mass when the mass obtained by calcining the limestone with a grinder, or spraying steam into the grinder.

(2) A method of spraying water or steam into the fluidized bed of the ground lime powder.

(3) A method in which crushed quick lime powder is flowed with moist air.

However, in the method (1), since water or the like comes into contact with the surface of the quicklime mass, only the surface is digested, the digestion lacks uniformity, and the surfactant used as a grinding aid is expensive. , The cost of the product will be high.

The method (2) requires complicated equipment for forming a fluidized bed. The method (3) is a simple method, but it is difficult to perform uniform selective digestion.

[Problems to be solved by the invention]

The present invention solves the above-mentioned disadvantages of the conventional method, and selectively digests the soft-baked portion with an extremely simple structure, thereby improving productivity and improving product quality. It is intended to provide a manufacturing method.

[Means for solving the problem]

According to the present invention, in order to achieve this object, massive quicklime obtained by calcining limestone is pulverized by an air-flow classifying pulverizer, and then the pulverized quicklime powder is blown tangentially into the pulverizer. Or, while being swirled upward through the pulverizer by an air flow to be sucked, high-pressure water having a pressure of 5 kg / cm ² or more corresponding to the soft-burning portion amount of the quicklime powder has a pore diameter of 1 to 3 mm. The method for producing quicklime powder for lightweight cellular concrete is sprayed from a nozzle in such a manner that the quicklime is sprayed in parallel with the flowing direction of the quicklime powder.

 Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 is an overall schematic view of an example of an apparatus used for carrying out the present invention.

In the figure, massive lime 1a introduced from a raw material supply port 1 of an air flow classifying crusher 10 is crushed between an inner lining plate 4 and a rotating roller 3 rotated by a rotating shaft 2. The pulverized quicklime powder is swirled upward in the pulverizer 10 by the airflow 5a blown tangentially from the lower wind pipe 5. High-pressure water of 5 kg / cm ² or more corresponding to the amount of the soft-burning portion was applied to the quicklime powder, and a plurality of pores having a diameter of 1 mm were provided on the side wall of the crusher 10.
A spray is sprayed uniformly through the nozzle 6 having a diameter of about 3 mm in parallel with the flowing direction of the quicklime powder. Since the contact time between the sprayed water and the quicklime powder is short, only the soft-burned part, which has a high reaction rate with water in the quicklime powder, selectively reacts with water and is partially digested to form water with the quicklime powder as a whole. Becomes mild.

Thus, the quick-lime powder selectively partially digested in contact with the sprayed water is classified by the cyclone 8 and the required fine powder is collected through the conduit 9, while the coarse powder separated by the cyclone 8 Is a crusher from the outlet 8a at the bottom of the cyclone 8.
It is crushed again in 10 returned. At this time, when the selective partial digestion is not sufficiently performed only by the spray water from the nozzle 6, the nozzle 6 a having the same hole diameter of 1 to 3 mm provided in the conduit 9 is used.
, It is possible to further spray high-pressure water of 5 kg / cm ² or more.

The air flow 5a introduced into the pulverizer from the lower wind tube 5 may be by blowing or by suction from the conduit 9 or later.

In the method of the present invention, the sprayed water uniformly contacts the quicklime which is swirled upward in the pulverizer 10 to selectively perform partial digestion, and at this time, the nozzle holes are blocked with quicklime powder. In order to prevent this, it is required that the nozzle diameter is in the range of 1 to 3 mm, the spray water pressure is 5 kg / cm ² or more, and the spray direction of the water is parallel to the flowing direction of the quicklime powder. You.

Since the amount of soft-burned portion in the quicklime mass usually varies, it is preferable to measure the amount of soft-burned portion each time it is necessary, and to quickly adjust the amount of spray water based on the result. It is sufficient that the amount of spray water is sufficient to selectively partially digest only the soft-burnt portion. The amount of water in the nozzle 6 or 6a may be increased or decreased, and the number of nozzles 6 and 6a is not limited.

[Action]

Since the quicklime powder produced by the method of the present invention selectively digests only the soft-burned portion and contains the hard-burned portion as quicklime as it is, it is used as quicklime for ALC raw material to use other raw materials, for example, foaming. When mixing with agents and chemicals, pouring into a mold and molding, the heat generated by the reaction in the foaming process is extremely small, so the foaming process is stable,
In addition, the hard-fired part does not react rapidly in the early stage of the foaming process, and most of it reacts after the foaming process,
It is possible to improve the quality of the product and to improve the productivity by shortening the time required for curing before cutting.

〔Example〕

 Hereinafter, the method of the present invention will be specifically described with reference to examples.

Example 1 With respect to 100 parts of quicklime powder pulverized and pneumatically fed by the air-flow classifying pulverizer 10 shown in FIG.
High-pressure water with a pressure of 5 kg / cm ² was uniformly sprayed from the nozzle 6 of mm to classify the mixture, and then selectively partially digested quicklime powder was obtained. 10 parts of this quick lime powder, 35 parts of ordinary Portland cement, 55 parts of quartz sand
Parts, 60 parts of water and 0.06 parts of aluminum powder were mixed and slurried, injected into a mold, foamed and semi-cured, and then subjected to autoclave curing. No part was observed at all, and the compressive strength was as high as 48.1 kg / cm ² at an absolutely dry bulk specific gravity of 0.50, confirming good quality.

Example 2 Quicklime powder pulverized and air-flowed under the same conditions as in Example 1
High pressure water having a pressure of 5 kg / cm ² was sprayed uniformly from a nozzle 6 having a pore diameter of 3.0 mm at a ratio of 3 parts of water to 100 parts, and classification was carried out to obtain selectively partially digested quicklime powder. The ALC product produced from this quick lime powder in the same formulation as in Example 1 also contained no unreacted quick lime agglomerated portion, and had a good compressive strength of 49.7 kg / cm ² at an absolute dry bulk specific gravity of 0.50.

Example 3 Quicklime powder pulverized and air-flowed under the same conditions as in Example 1
High-pressure water of a pressure of 10 kg / cm ² was sprayed from a nozzle 6 having a hole diameter of 3.0 mm at a ratio of 3 parts of water to 100 parts and classified, and the obtained partially digested quicklime powder was used as a raw material in the same formulation as in Example 1. The manufactured ALC product did not contain unreacted quicklime aggregates, and the compressive strength was 47.6 kg / cm ² , also at a dry bulk specific gravity of 0.50.

Comparative Example 1 Quicklime powder pulverized and air-flowed under the same conditions as in Example 1
Water was sprayed at a pressure of 3 kg / cm ² from a nozzle having a pore diameter of 0.5 mm at a ratio of 3 parts of water to 100 parts, and the mixture was classified to obtain partially digested quicklime powder. The ALC product produced using this quick lime powder as a raw material in the same formulation as in Example 1 has a large amount of unreacted quick lime agglomerated parts, and has a compressive strength of 35.4 kg / c at an absolute dry bulk specific gravity 0.50.
It showed a low value of m ² and was not good in quality. This means that some nozzles are closed due to the small nozzle diameter, and the spraying is uneven and the spraying range is not sufficient, so that the total water amount was sufficient to digest the soft-burned part. Regardless, it indicates that the soft-burned portion could not be selectively and uniformly digested.

Comparative Example 2 High-pressure water having a pressure of 10 kg / cm ² was sprayed from a nozzle having a pore diameter of 0.5 mm at the same ratio as in Example 1 to quicklime, which was pulverized and air-fed under the same conditions as in Example 1, and classified. A partially digested quicklime powder was obtained. Example 1 using this quicklime powder as a raw material
The product prepared in the same formulation as above contained a small amount of unreacted quicklime aggregates, and the compressive strength was 38.4 kg / cm ² at an absolute dry bulk specific gravity of 0.50.

〔effect〕

As described in detail above, the method of the present invention enables quality improvement of quick lime powder for ALC raw material and extremely high productivity with a very simple configuration, and its industrial value is large. .

[Brief description of the drawings]

FIG. 1 is an overall schematic view of an example of an apparatus used for carrying out the method of the present invention. 1 ... raw material supply port, 1a ... massive lime, 2 ... rotating shaft, 3 ... rotating roller, 4 ... lining plate, 5 ... lower wind pipe, 5a ... air flow, 6,6a ... Nozzle, 7 Damper, 8 Cyclone, 8a Cyclone outlet, 9 Pipe, 10 Air-flow classifier / pulverizer.

Claims (1)

(57) [Claims] 1. A lining plate and a rotating roller are arranged at a lower part, a cyclone is arranged at an upper part, a wind tube is connected to a lower side of the lining plate and the rotating roller, and a discharge conduit is connected to an upper part of the cyclone. In an air-flow classification crusher for pulverizing lump of lime obtained by calcining limestone between a lining plate and a rotating roller, a plurality of nozzles are provided on a side wall, and pulverized lime powder is tangentially inserted into the crusher. The air is blown or sucked into the pulverizer and swirled upward through the pulverizer, and the calcined lime powder is adjusted to a water amount corresponding to the fluctuation amount of the soft-burning portion while the pressure is adjusted to 5 kg / cm ^2. A method for digesting soft-burned portions of lightweight lime powder for lightweight cellular concrete, characterized by spraying the above high-pressure water from a nozzle having a hole diameter of 1 to 3 mm in parallel with the flowing direction of the quick lime powder.