JP4910756B2 - Method for manufacturing perlite - Google Patents

Description

The present invention relates to a method for producing pearlite widely used as a material for construction, heat insulation, soil improvement and the like.
More specifically, the present invention provides a method for efficiently and stably producing a high-quality pearlite having a predetermined unit volume mass using natural glassy rock as a raw material.

Perlite is a porous body obtained by crushing natural glassy rock, adjusting the particle size, and then firing at a high temperature to soften the glass in the rock and simultaneously release water in the rock to cause foaming. The natural vitreous rocks used are obsidian, pearlite, and pine sebite, and the driving force of foaming is gasification of water contained in the raw material rock. Depends greatly on the amount of water present and the firing temperature that drives foaming.

As a method for producing pearlite using natural vitreous rocks, Patent Document 1 discloses that natural vitreous rocks, especially pearlite and pine stones, which are abundant in resources, are used for building materials and have low strength and low water absorption. There is disclosed a method for producing spherical pearlite that has not only the properties but also excellent fluidity when used in mortar applications.

  Patent Document 2 discloses a heating apparatus using nacreite and pine sebite as an alternative to obsidian as a foaming pearlite for building materials, which has satisfactory properties such as strength but good results but is difficult to obtain due to resource depletion. The heating zone is made into a plurality of zones, foamed in the first zone 900 to 1100 ° C., the second zone 850 to 1100 ° C., the third zone 500 to 1000 ° C. from the raw material supply side, and the product using obsidian A method for producing pearlite to obtain an equivalent or higher foamed product is disclosed.

JP-A-9-183612 JP-A-7-277851

Perlite, which is widely used as a material for construction, insulation, and soil improvement, has different characteristics depending on the application and usage conditions, and unit volume mass is one of its typical physical properties. is there.

When supplying pearlite used in various applications, it is required to manufacture and supply pearlite having a unit volume mass suitable for the application. As a method for producing pearlite having a required unit volume mass, a pearlite having a unit volume mass smaller than the required unit volume mass and a pearlite having a larger unit volume mass are mixed to obtain a target unit volume mass. In the first place, pearlite is very light and the physical strength of each particle is relatively small, so when mixing with a general mixing device, the foam particles are destroyed and the target unit is destroyed. Volumetric pearlite cannot be obtained. For this reason, it is almost impossible to uniformly mix while avoiding destruction of pearlite particles without using an expensive and special mixing device.

In addition, in order to obtain pearlite of the target unit volume mass, the raw stone that can obtain pearlite of unit volume mass smaller than the target unit volume mass is used. A method of producing pearlite with some suppression is also conceivable. In the case of this method, the obtained pearlite can apparently achieve the target unit volume mass, but the pearlite becomes a mixture of fully foamed pearlite and raw unfoamed pearlite (raw stone). After packaging, foamed particles and unfoamed particles are separated by vibrations such as transportation, and there is a problem that the quality of the perlite packed in the same flexible container or paper bag varies. In addition, when pearlite containing unexpanded particles is used for plastering material, the unexpanded particles do not collapse when subjected to negative pressure, streaks due to unexpanded particles occur on the surface of the mortar, and are used as raw materials for siding boards. Also, if there are unfoamed particles on the board surface, the unfoamed particles are peeled off and a concave portion is likely to be generated on the surface, which makes it difficult to finish the surface smoothly.

The present invention allows efficient use of high-quality pearlite having a target unit volume mass, without using expensive and special mixing equipment, and containing almost no unfoamed pearlite, for pearlite used in various applications. And it aims at providing the method which can be manufactured stably.

As a result of intensive research on a method for efficiently and stably producing pearlite having a unit volume mass suitable for various applications and use conditions, the present inventors have found that the unit volume mass after firing and foaming differs. Select and use two kinds of natural vitreous rocks that have the same or relatively close firing temperature range to obtain a good foaming state, and mix, fire, and foam them, or put them separately into the firing equipment The present invention has been completed by finding that by firing and mixing, pearlite having a target unit volume mass can be stably and efficiently produced with almost no unfoamed particles.

That is, the first of the present invention is
A method for producing pearlite by firing and foaming two types of natural glassy rocks having different unit volume masses after firing and foaming at a temperature of 950 ° C. to 1250 ° C. A method for producing pearlite, which comprises mixing or pulverizing, and firing and foaming the mixture in the above temperature range.
The second of the present invention is
A method for producing perlite in which two kinds of natural vitreous rocks having different unit volume masses after firing and foaming are fired and foamed at a temperature of 950 ° C. to 1250 ° C., wherein two kinds of natural vitreous rocks are pulverized. The method for producing pearlite is characterized in that it is separately charged into a firing device and fired and mixed in the firing device.

The preferable aspect of the pearlite manufacturing method of this invention is shown below. A plurality of preferred embodiments can be combined.
1) The two types of natural glassy rocks have a unit volume mass after firing and foaming of 0.02 to 0.09 kg / liter and 0.1 to 0.5 kg / liter, respectively.
2) Natural vitreous rock (X parts by mass) having a unit volume mass of 0.02 to 0.09 kg / liter after firing and foaming and 0.1 to 0.5 kg / liter of unit volume mass after firing and foaming. The mixing ratio with the natural glassy rock (Y part by mass) is X / Y = 2/98 to 90/10.
3) The unit volume mass of pearlite obtained by firing two types of natural glassy rocks is 0.05 to 0.3 kg / liter.
4) The two types of natural glassy rocks are pearlite and / or pinestone.
5) Two kinds of natural glassy rocks are each preliminarily heated at a temperature of 150 to 800 ° C. and adjusted to a water content of 0.5 to 4% by weight, or pulverized, or pulverized to 150 to Pre-heating at a temperature of 800 ° C. to adjust the water content to 0.5 to 4% by weight.
6) Perlite must be for plastering or siding boards.

The present invention is a method for producing pearlite by firing and foaming two types of natural vitreous rocks having different unit volume masses after firing and foaming at a temperature of 950 ° C. to 1250 ° C. Pearlite, characterized by pulverizing and mixing, and firing and foaming the mixture in the above temperature range, or pulverizing and separately feeding two kinds of natural glassy rocks into a firing device It is a manufacturing method.
According to the present invention, the temperature at which the two types of natural vitreous rocks are both sufficiently foamed is selected as the firing temperature, and the mixing ratio of the two types of natural vitreous rocks dried and crushed is changed. By firing at the temperature, the unit volume mass of pearlite can be stably controlled within a certain range.
The pearlite obtained in the present invention can avoid the remaining of unfoamed particles because both of the two types of natural vitreous rocks are in a good foamed state, while maintaining the properties and quality of the obtained pearlite in good condition. It is possible to produce pearlite having an arbitrary unit volume mass.
Furthermore, the pearlite of the present invention is particularly excellent in applications for plastering materials and siding boards because it prevents streaking during plastering mortar application due to the remaining unfoamed particles and the occurrence of recesses on the surface of the siding board. Demonstrate performance.

The pearlite manufacturing method of the present invention will be described.
In the present invention,
(1) A first step of drying two types of natural vitreous rocks (raw material rocks) having different unit volume masses after firing and foaming,
(2) A second step of individually crushing two types of rocks (raw material rocks) having different unit volume masses after firing and foaming dried in the first step,
(3) Two types of rock grains (crushed material of raw material rock) having different unit volume masses after calcination and foaming pulverized in the second step are obtained in two types so as to obtain a target unit volume mass perlite. A third step of mixing at a rate calculated from the unit volume mass of the rock after foaming;
(4) Fourth step of baking and foaming the rock particle mixture (mixture of raw material rocks) prepared in the third step at a temperature of 950 to 1250 ° C.,
Through the above four steps, pearlite having a target unit volume mass can be stably and efficiently manufactured.
In the first step, if necessary, preheating may be performed at a temperature of 150 to 800 ° C. to remove a part of the contained water, and the water content may be adjusted to 0.5 to 4% by weight. Further, in order to perform preheating more efficiently, the preheating may be performed by pulverizing to a particle size that is easy to preheat in advance. Moreover, you may classify | pulverize the rock particle | grains as needed, and may adjust a particle size.
In the second step, the two types of rock dried in the first step are mixed and crushed at a ratio calculated from the unit volume mass after foaming of the two types of rock so as to obtain the target unit volume mass perlite. You may do it.
Furthermore, in the fourth step, the rock particles adjusted in the second step may be separately and quantitatively supplied to the rotary kiln or airflow firing furnace so as to achieve the target mixing ratio, and may be fired and mixed. The mixing step before firing can be omitted.

In the present invention, for natural glassy rocks having different foaming ratios at the time of firing, unit volume when fired at each temperature of 25 ° C. in a temperature range of 950 to 1250 ° C. using dried, crushed and classified rock grains The mass is measured, and the expansion ratio (unit volume mass of rock grains / unit volume mass after firing / foaming) with respect to the unit volume mass of the fine stone before firing is determined.
In addition, natural glassy rocks with different foaming ratios at the time of firing are natural glassy rocks with different rock types and production areas, or natural glassy rocks with the same rock types and production areas, but with different sampling locations. The foaming ratio at the time is different.

In the present invention, two kinds of natural vitreous rocks having different expansion ratios are selected and used. The criteria for selection will be described with reference to FIG.
When selecting two types of natural vitreous rocks from a wide variety of natural vitreous rocks with different rock types and localities, or natural glassy rocks with the same rock type and locality but different moisture content In addition, the temperature range g in which each natural glassy rock has a good foaming ratio is obtained, and the temperature range g where the f overlaps is preferably a temperature range of 20 ° C or higher, more preferably a temperature range of 30 ° C or higher More preferably, the temperature range is 40 ° C. or higher, and particularly preferably the temperature range is 45 ° C. or higher, in order to stably fire and foam two types of natural vitreous rocks, respectively. .
The temperature ranges e and f at which a good expansion ratio can be obtained are temperatures at which an expansion ratio of 95% or more is obtained with respect to the maximum expansion ratio h and i when fired and foamed at 950 to 1250 ° C. It means the ranges e and f.
When the temperature range g (minimum temperature: t1, upper limit temperature: t2) at which the above-mentioned favorable foaming ratio is obtained is less than 20 ° C., both the two types of natural vitreous rocks have a good foaming state. Since the firing / foaming temperature range for obtaining is extremely narrow, it is not preferable because a pearlite in a good foamed state may not be stably obtained. Further, when the temperature ranges e and f do not overlap, one of the two kinds of natural vitreous rocks is not preferable because a good foamed state cannot be obtained.

  Next, two kinds of natural vitreous rocks (A, B) in which the difference in the temperature range where a good foaming ratio is obtained is preferably 20 ° C. or more so as to obtain a pearlite having a target unit volume mass. And set the firing / foaming temperature (T ° C, t1 <T <t2)) to obtain a good foaming state for both of these two types of natural glassy rocks, and mix the two types of natural glassy rocks. The ratio is calculated and calculated by the following formula.

Natural glassy rock (X parts by mass) having a unit volume mass of 0.02 to 0.09 kg / liter after firing and foaming and natural glass having a unit volume mass of 0.1 to 0.5 kg / liter after firing and foaming The mixing ratio with the rock (Y part by mass) is preferably in the range of X / Y = 2/98 to 90/10, more preferably X / Y = 5/95 to 80/20, more preferably X / Y = 15/85 to 75/25, particularly preferably X / Y = 25/75 to 70/30. The unit volume mass of pearlite that is mixed and fired outside the range of the preferred mixing ratio is not preferable because the difference between the unit volume mass of pearlite obtained by firing each rock alone is small.

The unit volume mass of pearlite fired and foamed using two kinds of natural glassy rocks is preferably 0.05 to 0.3 kg / liter, more preferably 0.06 to 0.27 kg / liter, and particularly preferably 0. 0.07 to 0.25 kg / liter is preferable for use in a wide range of applications, and the two kinds of natural vitreous rocks may be mixed so that the unit volume weight of pearlite after firing and foaming is in the above range. preferable.
The unit volume mass of pearlite obtained by firing and foaming is less than 0.05 kg / liter, and can be easily obtained by firing one type of natural glassy rock. In the case where the merits of the pearlite are less than 0.3 kg / liter, the effect of reducing the weight of pearlite is reduced.

In order to stably produce pearlite having a unit volume mass of 0.05 to 0.3 kg / liter after firing and foaming, as two types of natural vitreous rocks with different foaming ratios,
Preferably, natural vitreous rock having a large foaming ratio with a unit volume mass of 0.02 to 0.09 kg / liter after firing and foaming, and a unit volume mass after firing and foaming of 0.1 to 0.5 kg / liter Using natural glassy rock with a small foaming ratio,
More preferably, natural vitreous rock having a large foaming ratio with a unit volume mass after firing / foaming of 0.025 to 0.08 kg / liter, and a unit volume mass after firing / foaming of 0.12-0.4 kg / liter. Using natural glassy rock with a small expansion ratio of liters,
Particularly preferably, natural vitreous rock having a large foaming ratio of 0.03 to 0.07 kg / liter after firing and foaming, and a unit volume weight after firing and foaming of 0.15 to 0.35 kg / liter. By using natural glassy rock with a small expansion ratio of liter, pearlite can be produced by controlling the unit volume mass in a wide range.

  When the unit volume mass after firing and foaming of natural glassy rock having a large expansion ratio is less than 0.02 kg / liter, the strength of the pearlite particles produced is too low, which is not practically preferable. Moreover, when larger than 0.09 kg / liter, it approximates to the unit volume mass (0.1-0.5 kg / liter) after baking and foaming of a natural glassy rock with small foaming ratio, and foaming ratio is Since the range of the unit volume mass of the pearlite which can be adjusted using two different kinds of natural glassy rocks becomes narrow, it is not preferable.

  When the unit volume mass after firing / foaming of natural glassy rock with a small expansion ratio is larger than 0.5 kg / liter, the unit volume mass after firing / foaming of natural glassy rock with a small foaming ratio (0.02 to 0) .09 kg / liter) is too large, and even if the target unit volume mass is obtained immediately after the manufacture of pearlite, material separation may occur in the course of operations such as transportation. Absent. Moreover, when it is smaller than 0.1 kg / liter, it approximates the unit volume mass (0.02 to 0.09 kg / liter) after firing and foaming of natural glassy rock having a large foaming ratio, and the foaming ratio is different. Since the range of the unit volume mass of the pearlite which can be adjusted using a kind of natural glassy rock becomes narrow, it is not preferable.

In the present invention, two kinds of natural vitreous rocks having different foaming ratios are used.
As natural glassy rocks, it is preferable to use two types of rocks selected from pearlite and / or rosinite, which have different expansion ratios, and obsidian that differs greatly in calcination conditions such as calcination time from pearlite and pineseite is used. Can not.

The natural vitreous rock used for the raw material is preferably preheated at a temperature of 150 to 800 ° C. as necessary to remove a part of the contained water and adjust the water content to 0.5 to 4% by weight. . When the preheating temperature is lower than 150 ° C., the moisture is difficult to volatilize, and it is necessary to lengthen the preheating time, which is not practical because it is not practical. When the preheating temperature is higher than 800 ° C., the volatilization rate of the water is increased, Since adjustment of quantity becomes difficult, it is not preferable. Moreover, when the water content is adjusted to 0.5 to 4% by mass, explosive foaming is suppressed, and a foam having a low water absorption rate composed of closed-type pores can be obtained.
When the water content is less than 0.5% by mass, foaming becomes insufficient during firing and foaming, and it becomes difficult to reduce the unit volume mass to 0.3 kg / liter or less. Since unfoamed particles may be mixed in the obtained pearlite, it is not preferred, and when it is 4% by mass or more, overfoaming occurs during the firing process and open pores are easily generated, which is not preferred.

As a device for drying and preheating natural glassy rocks, for example, a heating device used in a normal drying process such as a rotary dryer or an electric furnace can be appropriately selected and used.

As a crushing apparatus used for crushing natural glassy rock, for example, a crushing apparatus usually used such as a jaw crusher, a ball mill, and a vertical mill can be used as appropriate, and these can be used in combination as necessary. it can.

Two kinds of rock grains prepared by preheating two kinds of natural glassy rocks with different bulk specific gravity at the time of firing and foaming are mixed so as to obtain pearlite having a target unit volume mass after firing and foaming. Set to mix evenly.
As a mixing apparatus used for the mixing treatment, a general mixing apparatus used for mixing sand, blast furnace slag powder, cement, or the like can be appropriately selected and used.

Two kinds of natural vitreous rock particle mixtures having different bulk specific gravities at the time of firing and foaming are calcined and foamed by selecting a temperature at which each rock particle foams well, preferably in the range of 950 to 1250 ° C, By firing and foaming preferably in the range of 1000 to 1200 ° C., particularly preferably in the range of 1025 to 1175 ° C., pearlite in a good foamed state can be stably produced.
In addition, the two kinds of natural glassy rocks may be separately quantitatively supplied to a firing apparatus and fired and mixed at the firing temperature so that a target unit volume mass can be obtained. In the case of this method, the step of mixing two kinds of fine stones before firing can be omitted.
The firing apparatus used for firing and foaming is not particularly limited as long as it can stably maintain the preferred firing temperature in the present invention. For example, a rotary kiln, an electric furnace, a vertical airflow firing furnace, or the like is used. What is generally used at the time of manufacture can be used.

The pearlite obtained by firing and foaming by the production method of the present invention satisfies a predetermined unit volume mass that matches each application without performing a mixing operation for adjusting the unit volume mass, and is used for various applications. Can be suitably used.
In addition, by adjusting the mixing ratio of two kinds of natural glassy rocks (raw stones), it is possible to accurately realize a unit volume mass suitable for the intended use and conditions, and two kinds of natural glassy rocks (raw stones) Each baked pearlite does not contain unfoamed particles because it is fired under conditions that can obtain a high expansion ratio, and when it is used as a raw material for plastering mortars and siding boards, it has excellent characteristics. Can do.

The present invention will be specifically described below with reference to examples and comparative examples.
(1) As a measurement raw material in a temperature range where a good expansion ratio can be obtained, pearlite produced in Saga Prefecture is heated at 250 ° C. for 20 minutes, pulverized to a particle size of 0.3 to 0.6 mm, and obtained by adjusting the particle size. The rock particles (fine stone) obtained by heating the pearlite from Oita Prefecture at 300 ° C. for 20 minutes, crushing it to a particle size of 0.3 to 0.6 mm, and adjusting the particle size. used.
A brown mill (manufactured by Yoshida Seisakusho) was used for the pulverizer, and a box-type electric furnace (manufactured by Advantech Toyo) was used for the heat treatment. The water content calculated from the loss on ignition of each rock grain was 3.0% for pearlite from Saga Prefecture and 2.1% for pearlite from Oita Prefecture. These rock grains (fine stones) were individually fired at a temperature of 950 to 1150 ° C. for 30 seconds using a box-type electric furnace. The unit volume mass of each rock grain (fine stone) and box-type electric furnace fired product was measured according to JIS A 5007, and the expansion ratio was determined.
The results are shown in FIG. The temperature range in which the ratio of the maximum foaming ratio is 95% or more is 1085 to 1150 ° C for Saga pearlite, 1070 to 1128 ° C for Oita pearlite, and the temperature range of 1085 to 1128 ° C. Then, both were able to obtain a good expansion ratio in common.

(2) Manufacture of pearlite Pearlite produced in Saga Prefecture was heated at 250 ° C. for 20 minutes and pulverized to 0.3 mm. The pearlite produced in Oita Prefecture was heated at 300 ° C. for 20 minutes and crushed to 0.3 mm. Each rock grain (fine stone) is individually used in a vertical airflow firing furnace (furnace inner diameter; φ50 mm, length: 1 m), and both can obtain a good foaming ratio at 1100 ° C. Firing was performed to obtain pearlite A and H. As a result of measuring the unit volume mass of the obtained pearlite in accordance with JIS A 5007, the unit volume mass of pearlite A obtained by firing pearlite produced in Saga Prefecture is 0.051 kg / liter. The unit volume mass of pearlite obtained by calcining pearlite from the prefecture was 0.178 kg / liter.

Next, the target unit volume mass of fired pearlite is set to 0.09 kg / liter, 0.12 kg / liter, 0.16 kg / liter, and the mixing ratio of pearlite from Saga and pearlite from Oita is about each case. Calculated. The calculation results are shown below.

前記の計算結果に基づいて、表１に示す配合比率で佐賀県産真珠岩と大分県産真珠岩とを別々の定量供給装置を用いて縦型気流焼成炉に送入し、縦型気流焼成炉下部より７８０ｍｍの部分の温度を１１００℃に保持して焼成・混合し、パーライトＥ〜Ｇ（実施例１〜３）を得た。
また、佐賀県産真珠岩の岩石粒（精石）のみを使用して、焼成パーライトの目標の単位容積質量を０．０９ｋｇ／リットル、０．１２ｋｇ／リットル、０．１６ｋｇ／リットルとし、焼成温度をそれぞれ１０８０℃、１０７０℃、１０５０℃に保持して焼成し、パーライトＢ〜Ｄ（比較例１〜３）を得た。なお、目標の単位容積質量に対応した焼成温度は、事前に佐賀県産真珠岩について焼成温度に対する発泡倍率を測定した結果（図２）に基づいて設定した。

Based on the above calculation results, the Saga pearlite and the Oita pearlite are fed into the vertical airflow firing furnace using separate quantitative feeders at the mixing ratio shown in Table 1, and the vertical airflow firing is performed. The temperature of the part of 780 mm from the lower part of the furnace was kept at 1100 ° C. and fired and mixed to obtain perlites E to G (Examples 1 to 3).
In addition, using only pearl rocks (fine stone) from Saga Prefecture, the target unit volume mass of calcinated pearlite is set to 0.09 kg / liter, 0.12 kg / liter, 0.16 kg / liter, and the calcination temperature. Were held at 1080 ° C., 1070 ° C. and 1050 ° C., respectively, and fired to obtain pearlite B to D (Comparative Examples 1 to 3). In addition, the calcination temperature corresponding to the target unit volume mass was set based on the result (FIG. 2) which measured the foaming ratio with respect to calcination temperature beforehand about the pearl rock produced in Saga.

(3) Measurement of physical properties of pearlite The unit volume mass of the obtained pearlite (B to G) was measured according to JIS A 5007 as described above.
Next, pearlite (A to H) is filled in a 5 liter plastic cylindrical container (inside dimensions; diameter φ160 mm, height 270 mm), and the container is fixed to a table vibrator (manufactured by Maruto Seisakusho) for 10 minutes. After applying vibration, pearlite in the upper part of the plastic cylindrical container (up to 160mm from the top) and pearlite in the lower part (up to 110mm from the bottom) are collected separately, and each unit volume mass conforms to JIS A 5007. The difference in unit volume mass between the upper part and the lower part in the container was measured.
Table 3 shows the measurement results of the unit volume mass.
Moreover, the shape of the obtained pearlite was observed with a scanning electron microscope (JSM-5400, manufactured by JEOL Datum). The results of observation are shown in FIGS.

(4) A pearlite mortar streaking test The obtained pearlite A to H is cemented with water (usual portland cement manufactured by Ube-Mitsubishi Cement Corporation) and water having a flow value measured according to JIS A 5201 of 180 to 200 mm. And an admixture (Yamaso Chemical Co., Ltd., Vinsol W) were added and kneaded for 3 minutes with a Hobart mixer to prepare a mortar. Table 2 shows the composition of the mortar.
The plastered mortar and mortar board were used to apply the entire amount of the mortar that had been kneaded, and the mortar was rubbed together by applying pressure, and the number of streaks generated on the surface of the mortar was measured.
Table 3 shows the measurement results of the number of streaks generated on the mortar surface.

The unit volume mass of pearlite A (Reference Example 1) obtained by firing at 1100 ° C. using pearlite from Saga as a raw material is 0.051 kg / liter when vibration is not applied, and a container when vibration is applied. The difference in the unit volume mass of pearlite collected from the upper part and the lower part was as small as 0.004 kg / liter.
Perlite B, C, and D (Comparative Examples 1, 2, and 3) fired at a temperature of 1050 to 1080 ° C. from the lower part of the vertical airflow firing furnace using pearlite from Saga as a raw material, are not applied with vibration. The unit volume mass of each was 0.083 kg / liter, 0.111, kg / liter, and 0.150 kg / liter, which were almost the target unit volume mass, but when vibration was applied, unexpanded particles were caused by vibration. Moved to the lower part, the difference in unit volume mass of pearlite collected from the upper part of the container and the lower part of the container was as large as 0.035 kg / liter or more. Further, unexpanded particles were confirmed from the result of microscopic observation of perlite C. Furthermore, even in the streak pulling test for mortar using these pearlites, since pearlite B to C does not collapse even when unfoamed particles are subjected to a negative pressure, the number of streaks is as large as 19 to 47, and a good finished surface Could not be formed.
Perlites E to G (Examples 1 to 3) obtained by firing and mixing raw stones produced in Saga and Oita produced a unit volume mass almost as intended. In the case of these pearlites, the result of measuring the difference in unit volume mass of pearlite collected from the top and bottom of the container even when vibration was applied was as small as 0.021 kg / liter or less, and unexpanded particles were observed by microscopic observation. I couldn't. Furthermore, as a result of the mortar streaking test, no streaks due to the remaining unexpanded particles were generated, and a good mortar finished surface could be formed.

It is a schematic diagram which shows the change of the unit volume mass and foaming magnification at the time of baking two types of natural glassy rocks from which foaming magnification differs at various temperatures. It is a schematic diagram which shows the change of a foaming magnification at the time of baking two types of natural glassy rocks from which a production area differs and foaming magnification differs at various temperatures. It is an electron micrograph of perlite A obtained by baking pearlite from Saga Prefecture. It is an electron micrograph of pearlite C obtained by baking pearlite from Saga Prefecture. It is an electron micrograph of perlite F obtained by baking and mixing pearlite from Saga and pearlite from Oita. It is an electron micrograph of perlite G obtained by baking and mixing pearlite from Saga and pearlite from Oita.

Claims (7)

Firing and foaming natural glassy rock in a temperature range of 950 to 1250 ° C., and determining a foaming ratio (unit volume mass before firing / foaming / unit volume mass after firing / foaming);
The unit volume mass after firing and foaming of the natural glassy rock is 0.02 to 0.09 kg / liter and 0.1 to 0.5 kg / liter,
And two kinds of natural vitreous rocks whose overlap of the temperature range in which a foaming ratio of 95% or more is obtained is 20 ° C or more with respect to the maximum foaming ratio when fired and foamed in a temperature range of 950 to 1250 ° C. A process of selecting
Crushing the selected two kinds of natural vitreous rocks separately and putting them into a firing device, firing and mixing in the firing device within the temperature range ;
The manufacturing method of the pearlite which has . Firing and foaming natural glassy rock in a temperature range of 950 to 1250 ° C., and determining a foaming ratio (unit volume mass before firing / foaming / unit volume mass after firing / foaming);
The unit volume mass after firing and foaming of the natural glassy rock is 0.02 to 0.09 kg / liter and 0.1 to 0.5 kg / liter,
And two kinds of natural vitreous rocks whose overlap of the temperature range in which a foaming ratio of 95% or more is obtained is 20 ° C or more with respect to the maximum foaming ratio when fired and foamed in a temperature range of 950 to 1250 ° C. A process of selecting
Crushing and mixing the selected two kinds of natural glassy rocks, or mixing and crushing, and firing and foaming the mixture in the temperature range ;
The manufacturing method of the pearlite which has . Natural glassy rock (X parts by mass) having a unit volume mass of 0.02 to 0.09 kg / liter after firing and foaming and natural glass having a unit volume mass of 0.1 to 0.5 kg / liter after firing and foaming The method for producing pearlite according to claim 1 or 2, wherein a mixing ratio with the rock (Y part by mass) is X / Y = 2/98 to 90/10. The unit volume mass of pearlite obtained by firing two kinds of natural glassy rocks is 0.05 to 0.3 kg / liter, according to any one of claims 1 to 3 . A manufacturing method of pearlite. The two types of natural vitreous rocks are pearlite and / or rosinite, and the method for producing pearlite according to any one of claims 1 to 4 . Two kinds of natural glassy rocks are each preliminarily heated at a temperature of 150 to 800 ° C. and adjusted to a water content of 0.5 to 4% by weight and then pulverized, or pulverized and 150 to 800 ° C., respectively. The method for producing pearlite according to any one of claims 1 to 5 , wherein the moisture content is adjusted to 0.5 to 4% by weight by preheating at a temperature of 5 %. The method for producing pearlite according to any one of claims 1 to 6 , wherein the pearlite is for a plastering material or a siding board.

Images