JPH0238346A - Production of quick lime powder for lightweight cellular concrete - Google Patents

Abstract

PURPOSE:To selectively slake a soft calcined part and obtain the subject quick lime powder of improved quality by pulverizing a massive quick lime prepared by calcining limestone and treating the pulverized quick lime with high-pressure water under specific conditions. CONSTITUTION:A massive quick lime (1a) obtained by calcining limestone is fed from a raw material feeding port 1 into a pneumatically feeding classifying pulverizer 10 and pulverized with rotating rollers 3 to provide quick lime powder, which is then blown into the above-mentioned pulverizer 10 in the tangential direction or swirled and fed upward in the pulverizer 10 by air streams (5a) for suction. High-pressure water in an amount corresponding to the amount of a soft calcined part in the afore-mentioned quick lime powder under 15kg/cm<2> pressure is cocurrently sprayed from nozzles 6 having 1-3mm hole diameter in the flow feeding direction of the above-mentioned quick lime powder to selectively slake the soft calcined part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing quicklime powder for lightweight aerated concrete (hereinafter referred to as ALC).

[Conventional technology]

Generally, the quality of quicklime for use as an ALC raw material is required to be high in CaO purity and slow in reaction when it comes into contact with water. The reactivity as a quality characteristic of quicklime is closely related to the conditions for calcination of limestone when producing quicklime. In other words, quicklime obtained by firing limestone at a low temperature for a short time is called a soft-calcined product because it reacts quickly with water, and quicklime obtained by firing limestone at a high temperature for a long time is called a hard-calcined product. However, the reaction with water is slow. In other words, the soft filling product is A
When the LC raw material is mixed with other raw materials such as calcareous raw materials such as cement, silicic raw materials such as silica sand and silica stone, aluminum powder, water, and chemicals to form a slurry, a rapid digestive reaction occurs and a large amount of heat is generated. This rapidly removes water and loses the fluidity necessary for bubble formation during the foaming process, which causes problems such as disordered bubble shape and collapse after foaming.

Furthermore, sufficient dispersion of quicklime particles is inhibited, and unreacted quicklime aggregates are formed, resulting in a loss of raw materials and contributing to a decline in product quality.

On the other hand, with conventional lime burning techniques, it is extremely difficult to produce quicklime that consists only of hard-burned parts without soft-burned parts. Therefore, if the soft burnt parts that cause the above-mentioned problems are digested with water and slaked lime in advance, there will be no sudden heat generation when it reacts with water, and water will not be rapidly lost, so quicklime The particles have good dispersibility and do not form unreacted coagulated parts. As described above, partial digestion of quicklime powder is an effective means for obtaining quicklime as a raw material for ALC, and the following methods are known.

(2) A method in which a lump obtained by calcining limestone is crushed in a crusher, a method in which water or a crushing aid such as a diluted surfactant solution is sprayed onto the quicklime lump, or water vapor is sprayed into the crusher.

(2) A method of spraying water or steam into a fluidized bed of crushed quicklime powder.

(3) A method in which crushed quicklime powder is conveyed using air that has removed moisture.

However, in method (1), since water comes into contact with the surface of the quicklime lump, the surface gas is digested, resulting in uneven digestion, and the surfactant used as a grinding aid is It is expensive and increases the cost of the product.

Method (2) requires complicated equipment due to the formation of a fluidized bed. Method (3) is a simple method, but it is difficult to perform uniform selective digestion.

[Problem to be solved by the invention]

The present invention solves the drawbacks of the conventional method described above and selectively burns out the soft burnt parts with an extremely cylindrical structure, thereby improving productivity and product quality. Quicklime powder for lightweight aerated concrete The present invention provides a method for manufacturing.

[Means to solve the problem]

In order to achieve this object, the present invention crushes the lump quicklime obtained by calcining limestone in an air-flow classification crusher, and then blows the crushed quicklime powder into the crusher in a tangential direction. The air flow that is pumped or sucked is caused to circulate upward in the crusher, and the quicklime powder is subjected to a pressure of 5 kg /
The method for producing quicklime powder for lightweight cellular concrete is configured such that high-pressure water of 2 cm2 or more is sprayed from a nozzle with a hole diameter of 1 to 3 in parallel with the flow direction of the quicklime powder.

The present invention will be explained below with reference to the drawings.

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

In the figure, lump quicklime 1a introduced from the raw material supply port I of the air-flow classification and pulverization 41110 is pulverized between the lining plate 4 and the rotating roller 3 rotated by the rotating shaft 2. The crushed quicklime powder is swirled upward within the crusher 10 by an air flow 5a blown in tangentially from the lower wind pipe 5. High-pressure water of 5 kg/cm2 or more is applied to the quicklime powder according to the amount of the soft burnt portion of the quicklime powder through a plurality of nozzles 6 with hole diameters of 1 to 3 fins provided on the side wall of the crusher IO. Spray uniformly in parallel with the feeding direction. Since the contact time between the sprayed water and the quicklime powder is short, only the soft-burned part of the quicklime powder that has a high reaction rate with water selectively reacts with water and is partially digested, resulting in water and quicklime powder as a whole. The reactivity of is mild.

The quicklime powder, which has thus been selectively partially digested in contact with the sprayed water, is classified in cyclone 8 and the required fine powder is collected through conduit 9, while the coarse powder separated in cyclone 8 The pulverizer 4 is discharged from the outlet 8a at the bottom of the cyclone 8.
1110 and is crushed again. At this time, if selective partial digestion is not carried out sufficiently with water sprayed from the nozzle 6, a similar hole diameter of 1 to 3 mII provided in the conduit 9 may be used.
Same from nozzle 6a of I < 5 kr: / cs 2
The above high-pressure water can be further sprayed.

The air flow 5a introduced into the mill through the lower wind pipe 5 may be by blowing l or by suction from the conduit 9 onwards.

In the method of the present invention, the sprayed water uniformly contacts the quicklime powder swirling upward in the pulverization [10] to selectively perform partial digestion, and at the same time, the nozzle hole is blocked by the quicklime powder. In order to prevent this, the nozzle hole diameter must be in the range of 1 to 3 m, the spray water pressure must be 5 b/cya 2 or more, and the direction of water jetting must be parallel to the direction of flow of quicklime powder. required.

Since the amount of soft burnt portion in the quicklime lump usually varies, it is preferable to measure the amount of soft burnt portion each time when necessary and quickly adjust the amount of spray water based on the result. The amount of sprayed water is sufficient as long as it is sufficient to selectively partially digest only the soft-burned portion, and the amount of water in the nozzle 6 or 6a may be increased or decreased, and the number of nozzles 6.6a is not limited.

[Effect]

Since the quicklime powder produced by the method of the present invention selectively partially digests only the soft burnt part and contains the hard burnt part as quicklime, it can be used as quicklime powder for ALC raw materials and used for other raw materials, such as foaming. When molding is performed by mixing the mixture with agents and chemicals and injecting it into molds, the heat generation due to the reaction during the foaming process is extremely small, so the foaming process is stable, and the hard-burned part does not rapidly rise at the beginning of the foaming process. Since it does not react and most of it reacts after the foaming process is completed, it is possible to improve product quality and improve productivity by shortening the time required for curing before cutting.

〔Example〕

The method of the present invention will be specifically explained below using examples.

Example 1 To 100 parts of quicklime powder, which is pulverized by the air flow rate classification and pulverization $110 shown in FIG. Pressure 5 kg / cm 2 from nozzle 6 of Om
After uniformly spraying with high-pressure water and classifying, selectively partially digested quicklime powder was obtained. A slurry was prepared by mixing 10 parts of quicklime powder, 35 parts of ordinary Portland cement, 55 parts of silica sand, 60 parts of water, and 0.06 parts of aluminum powder, poured into a mold, foamed and semi-hardened, and then cured in an autoclave. As a result of measuring the physical properties of the two AlCl products obtained, no unreacted quicklime agglomeration was observed, and the compressive strength was as high as 48.1 kg/c 2 with an absolute dry bulk specific gravity of 0.50, indicating good quality. was confirmed.

Example 2 Quicklime powder 1 crushed and air-fed under the same conditions as Example 1
00 parts to 3 parts of water using a nozzle with a pore diameter of 3.0 mm.
After uniformly spraying high-pressure water at a pressure of 5 kg/cm 2 and classifying, selectively partially digested quicklime powder was obtained. The ALC product manufactured using this quicklime powder as a raw material and using the same formulation as in Example 1 is the same (does not contain unreacted quicklime agglomerated parts, and has a compressive strength of 40.7 kg / 40.7 kg with an absolute dry bulk specific gravity of 0.50)
It was good with ce 2.

Example 3 Quicklime powder 1 crushed and air-fed under the same conditions as Example 1
00 parts to 3 parts of water, the pore size is 3.0 parts. After spraying high-pressure water at a pressure of 10 kg/cya 2 from Ofi nozzle 6 and classifying, the ALC product was manufactured using the same formulation as in Example 1 using the partially digested quicklime powder obtained as raw material, and contained unreacted quicklime agglomerated parts. Also, the compressive strength is the same as the absolute dry bulk specific gravity of 0.
．． At 50, the weight was 47.6 kg/csa 2, which was good.

Comparative Example 1 Quicklime powder 1 crushed and air-fed under the same conditions as Example 1
After classification, partially digested quicklime powder was obtained by spraying water at a pressure of 3 kg/cm 2 from a nozzle with a pore diameter of 0.5 at a ratio of 3 parts water to 00 parts. The ALC product produced using this quicklime powder as a raw material and using the same formulation as in Example 1 contained a large amount of unreacted quicklime agglomerated parts, and the compressive strength was 35.4 kg/cam2 at an absolute dry bulk specific gravity of 0.50. The value was low and the quality was not good. This is because the nozzle's hole diameter is small and some of the holes are blocked, and the spray is uneven and the spray area is not sufficient, so the total amount of water was sufficient to digest the soft-burning part. However, this shows that the soft-burned portion could not be selectively and uniformly digested.

Comparative Example 2 High-pressure water at a pressure of 10 kg/cm 2 was sprayed at the same rate as in Example 1 from a nozzle with a hole diameter of 0.5 □ on quicklime powder that was crushed and air-fed under the same conditions as in Example 1, and was classified. After that, partially digested quicklime powder was obtained. A product manufactured from this quicklime powder using the same formulation as in Example 1 contains a small amount of unreacted quicklime agglomerated portion, and has a compressive strength of bone dry bulk specific gravity of 0.5.
0 was 38.4 kg/cm2, which was not good.

〔effect〕

As explained in detail above, the method of the present invention makes it possible to improve the quality of quicklime powder used as an ALC raw material and improve productivity by using an extremely simple configuration, and its industrial value is great. be.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram of an example of an apparatus used to carry out the method of the present invention. 1... Raw material supply port, la... Mass quicklime, 2...
... Rotating shaft, 3... Rotating roller, 4... Lining plate, 5... Lower wind pipe, 5a... Air flow, 6.6
a... Nozzle, 7... Damper 8... Cyclone, 8a... Cyclone outlet, 9... Conduit, lO... Air flow classification crusher. Patent applicant Sumitomo Metal Mining Co., Ltd.

Claims (1)

[Claims] 1. The lump quicklime obtained by calcining limestone is pulverized in an air-flow classification pulverizer, and then the pulverized quicklime powder is pulverized by an air flow tangentially blown or sucked into the pulverizer. At the same time, high-pressure water with a pressure of 5 kg/cm^2 or more is applied to the quicklime powder according to the amount of the soft burnt portion of the quicklime powder through a nozzle with a hole diameter of 1 to 3 mm in the direction of flow of the quicklime powder. A method for producing quicklime powder for lightweight aerated concrete, characterized by spraying it in parallel flow with.