JP5702638B2 - Impact-resistant perlite and method for producing the same - Google Patents

Description

The present invention relates to impact-resistant pearlite and a method for producing the same, and more particularly, to provide a method for producing pearlite having excellent impact resistance that is not easily destroyed during transportation or handling after production.

Perlite is a hollow particle obtained by heating and foaming mineral raw material particles such as nacre and obsidian, and is widely used as a light weight material. For example, it is used as a material for reducing weight by mixing pearlite into mortar, roof tiles, and outer wall materials.

Perlite is foamed in a diameter ratio of about 1.5 to 5 times with respect to the raw material particles, and the surface shell is a few microns, so it is very thin and easily damaged. It is partially broken during handling such as storage, transportation and final product production, and the bulk density during production gradually increases.

As a measure to prevent such destruction of pearlite, it is conceivable to increase the strength of pearlite by firing at low temperature and reducing the expansion ratio. However, when fired at low temperature, unfoamed particles are generated. Particles will be mixed. When such unexpanded particles are mixed, the unexpanded particles are heavy, so that there is a problem that impact is given to the surrounding expanded particles, and the ratio of the expanded particles is increased during transportation and handling of the product. In order to reduce such unfoamed particles, the entire raw material particles may be heated sufficiently by firing at a high temperature. However, when fired at a high temperature, excessive foaming occurs, and the thickness of the outer shell becomes thin. descend.

As another method for increasing the strength of pearlite, there is known a method of heating and foaming after preheating the raw material powder. Specifically, in pearlite made from nacre, the moisture contained in nacre acts as a foaming agent, the moisture evaporates by heating, and foams by the vaporized vapor when the temperature reaches the melting point or higher. If the amount of water is too large at this time, excessive foaming occurs, and the shell becomes thin and the strength is weakened. Therefore, a method is known in which excessive foaming is prevented by heating in advance to the foaming temperature after preheating to control the amount of water in the pearlite (Patent Documents 1 and 2).

In addition, after the raw material powder is preheated to adjust the moisture content, this raw material powder is mixed with the high melting point fine powder and foamed, and then the resulting foam (perlite) is separated from the high melting point fine powder. A method is also known (Patent Document 3). This production method is a method of producing spherical pearlite with less surface irregularities by uniformly foaming a preheated raw material powder into a high melting point fine powder and foaming.

JP-A-7-277851 JP 2007-320805 A Japanese Patent No. 3528390

In order to preheat the raw material, a preheating furnace is required in addition to the foaming heating furnace, and there is a problem that the manufacturing equipment becomes large. Also, the method of mixing preheated raw material powder with high melting point fine powder and heating and foaming requires supply equipment and separation equipment for high melting point fine powder, which increases the number of processes and increases the manufacturing cost. There is.

Furthermore, in any production method, the unfoamed material cannot be avoided. When unexpanded particles are mixed, the unexpanded particles are heavier than the expanded particles, so when subjected to external forces such as vibration during transportation or product handling, the unexpanded particles will impact the surrounding expanded particles and break them. There is a problem that the ratio increases. Even if the firing conditions are optimized and firing is performed using an improved firing furnace, it is difficult to produce pearlite free of unexpanded particles.

The present invention solves such problems, and provides a pearlite having excellent impact resistance that is not easily damaged during transportation and handling after production, and a method for producing the same.

The present invention relates to an impact-resistant pearlite having the following configuration and a manufacturing method thereof.
[1] Perlite formed by heating and foaming a mineral raw material, containing 80 vol% or more of low density particles having an apparent density of less than 1.0 g / cm ³ , a particle diameter of 45 μm or more, and an apparent density of 1.0 g / An impact-resistant pearlite having a high density particle content of cm ³ or more and 15 vol% or less , and further containing particles having an apparent density of 1.0 g / cm ³ or more and a particle diameter of less than 45 μm .
[2] The impact-resistant pearlite according to the above [1], having an average apparent density of 0.2 to 0.6 g / cm ³ .
[3] After heating and foaming the mineral material, it contains 80 vol% or more of low density particles having an apparent density of less than 1.0 g / cm ³ and has a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more. The particle size is 45 μm or more and the apparent density is 1.0 g / cm so that the high-density particle content is 15 vol% or less and the particles have an apparent density of 1.0 g / cm ³ or more and less than 45 μm. A method for producing impact-resistant pearlite that separates high-density particles of cm ³ or more.
[4] The above-mentioned [3], in which high-density particles having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more are fall-classified by adjusting the wind speed of the foamed particles to 10 to 50 m / sec under wind force. A method for producing the impact-resistant pearlite described.
[5] After high-temperature foaming of the mineral material, the foamed particles are placed in water and the settled particles are separated to separate high-density particles having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more. The method for producing impact-resistant pearlite according to [3] above.

In the pearlite of the present invention, the content of high-density particles having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more is reduced to 15 vol% or less. The number of particles is remarkably small. Therefore, the change in bulk density before and after pneumatic transportation is small, the impact resistance is excellent, and the material separation is difficult to occur.

In the production method of the present invention, after the raw material particles are heated and foamed, high density particles having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more are separated to form expanded particles with few high density particles. Therefore, it is possible to easily manufacture pearlite that has a small change in bulk density before and after pneumatic transportation and excellent in impact resistance.

Hereinafter, the present invention will be specifically described based on embodiments.
The pearlite of the present invention is a pearlite obtained by heating and foaming a mineral raw material, contains 80 vol% or more of low density particles having an apparent density of less than 1.0 g / cm ³ , and has a particle diameter of 45 μm or more and an apparent density of 1 .0g / cm ³ or more and a high-density particulate content of less 15 vol%, further impact perlite to this and characteristics, including apparent density 1.0 g / cm ³ or more in a by a particle diameter of less than 45μm particle is there. Here, the amount of particles having an apparent density of 1.0 g / cm ³ or more can be calculated by measuring the volume of particles that sink when pearlite is placed in water. Since the density of water is about 1.0 g / cm ³ in the liquid state and normal pressure, the sinked particles are particles of 1.0 g / cm ³ or more.

The pearlite of the present invention can be produced by separating and removing high-density particles having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more after heating and foaming the mineral material. .

The mineral material for producing pearlite is a raw material composed of a rocky powder that is foamed by heating. Specifically, pearlite, pine stone, obsidian, shirasu, etc. having water inside are used. In addition, granulated by adding a foaming agent such as SiC to silica glass raw material powder or fly ash containing unburned carbon inside is used.

The means (heating furnace etc.) for heating the raw material is not limited. A normal rotary kiln, airflow firing furnace, fluidized bed firing furnace, or the like can be used. Further, the means and method for supplying to the heating furnace and the like and the means and method for discharging are not limited.

Foamed particles (perlite) can be produced by placing mineral raw material particles having an average particle size of 50 to 200 μm in a heating furnace and heating them to approximately 750 to 1000 ° C. for foaming. The heating temperature may be adjusted according to the type and size of the firing furnace.

Generally, when nacreous particles having an average particle diameter of 150 μm are heated to about 800 ° C., foam particles having an average particle diameter of 180 μm to 300 μm (total bulk density of about 0.2 to 0.35 g / cm ³ ) are obtained. Depending on the state of the particles and the heated state, unexpanded particles or insufficiently expanded particles may be included, and usually high density particles having an apparent density of 1.0 g / cm ³ or more are generally included around 20 vol%. . The apparent density is the ratio of the particle mass to the volume of the particle including the internal cavity when there is a space in the particle and the internal space does not communicate with the outside, and the apparent density = particle mass / Expressed by particle volume (g / cm ³ ).

When such high density particles (heavy particles) collide with surrounding foam particles (light particles) having a low density, they tend to break them. In particular, high-density and heavy particles having a large particle size have large kinetic energy, and destroy many foamed particles at the time of collision. Therefore, when foam particles are produced by heating and foaming raw material particles, if high-density particles are contained, light foam particles are destroyed when the foam particles are pneumatically transported. The density change (density difference) of the expanded particles becomes large, and the entire expanded particles have low impact resistance.

Therefore, in the production method of the present invention, after the raw material particles are heated and foamed, particles having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more are separated, and the content is reduced to 15 vol% or less. Restrict. Particles with a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more tend to break when they collide with surrounding foamed particles (light particles) with a small bulk density. Remove density particles. In the present invention, particles having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more are referred to as high-density particles.

Even if the apparent density is 1.0 g / cm ³ or more, those having a particle diameter of less than 45 μm are less likely to cause a change in density by destroying surrounding light particles. Is acceptable. On the other hand, even if the particle diameter is 45 μm or more, particles having an apparent density of less than 1.0 g / cm ³ are light foamed particles, and most of the foamed particles are low-density particles. The pearlite of the present invention contains 80 vol% or more of low density particles having an apparent density of less than 1.0 g / cm ³ .

As a means for separating high-density particles having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more, a dry or wet specific gravity separator, a centrifugal specific gravity separator, or an inertial dust collector may be used. . As a dry separation method, for example, foam particles can be separated by dropping high-density particles having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more by adjusting the wind speed under wind force. Specifically, a separation device may be used in which a trap for collecting particles is provided at a lower portion of a transport pipe for pneumatic transportation, and the target particles are dropped by collecting air pressure (wind speed) and collected.

Specifically, when the foamed particles are pneumatically transported, by adjusting the wind speed to 10 to 50 m / sec, high density particles having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more are dropped. Can be separated. By this separation method, pearlite having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more and a content of high-density particles of 15 vol% or less can be obtained.

On the other hand, in order to separate high density particles having an apparent density of 1.0 g / cm ³ or more, levitation with respect to water may be used. When foamed particles are placed in water, heavy particles with an apparent density of 1.0 g / cm ³ or more will sink. Therefore, by separating the settled particles and collecting the floated particles, the apparent density is 1.0 g / cm ^3. Foamed particles that do not contain the above particles can be obtained. According to this separation method using water, it is possible to separate all the apparent density 1.0 g / cm ³ or more dense particles, apparent density 1.0 g / cm ³ or more regardless of the particle size Perlite with a high-density particle content of 15 vol% or less can be obtained.

In the pearlite of the present invention, the content of high-density particles having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more is 15 vol% or less, and preferably the average apparent density of the whole particles is 0.2 to 0.2%. It is 0.6 g / cm ³ and the content of low density particles having an apparent density of less than 1.0 g / cm ³ is 80% or more.

When the average apparent density is less than 0.2 g / cm ^{3, the} impact resistance is poor because the strength of the particles themselves is weak. When the average apparent density is larger than 0.6 g / cm ³ , the remaining high-density particle content is large, and the light weight effect is small even when used as a weight reducing material. Therefore, the average apparent density is suitably in the range of 0.2 to 0.6 g / cm ³ . Further, if the content of low density particles having an apparent density of less than 1.0 g / cm ^{3 is} less than 80%, the content of high density particles increases, which is not preferable.

In the pearlite of the present invention, the content of high density particles having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more is 15 vol% or less. If it is more than this, the bulk density change of the whole particles becomes large when pneumatically transported.

When there are many high-density particles in pearlite, this collides with light foam particles and breaks them, and the bulk density change of the whole particles becomes large. Conventional pearlite has such a large change in bulk density. On the other hand, since the pearlite of the present invention has a low content of high-density particles, the foamed particles are not easily broken and has excellent durability, so the change in bulk density due to handling during transportation or use is small.

Since the pearlite of the present invention has a low content of high-density particles, it is difficult to cause material separation during use. If the pearlite contains a large number of high-density particles, when processing the product by mixing pearlite with the material of the tile or wall material, it tends to cause material separation, resulting in problems such as variation in mass for each product. . Since the pearlite of the present invention has few high-density particles and hardly causes material separation, a high-quality product can be obtained.

In general, manufactured pearlite is stored in a product silo or the like, and transportation to the silo is mainly performed by pneumatic transportation. In pneumatic transportation, pearlite flows through the transport pipe by compressed air, so the pearlite flowing in the pipe receives air pressure. Further, since there are vertical and curved portions in the middle of the path, the pearlite flowing in the tube often comes into contact with the tube wall and is damaged by collision or friction. Furthermore, impact and pressure are applied to the pearlite during loading into the silo, storage, and transportation by truck or lorry vehicle. The pearlite of the present invention is small in density change due to such impact and pressure.

Examples of the present invention are shown below together with comparative examples. The bulk density, apparent density, average particle diameter, content of low density particles having an apparent density of less than 1.0 g / cm ³ , and residual density of high density particles were measured by the following methods.

[Bulk density] Fill a container with a constant volume S (cm ³ ), grind the portion protruding from the opening, measure the total weight G1, subtract the weight G2 of the container from this, and weight the powder G3 (g) The powder weight G3 [G3 / S] g / cm ³ with respect to the volume S was defined as the bulk density.
[Apparent density] Measured by a gas displacement method (Accupic 1330, manufactured by Shimadzu Corporation).

[Average particle size] Using sieves of 45, 90, 150, 300, and 600 μm, measure the mass of each sieve residue and the amount passed through, and use the HYPERLINK "http://kotobank.jp/word/%E5%AF" % BE% E6% 95% B0 "HYPERLINK" http://kotobank.jp/word/% "with logarithm as the horizontal axis and the passing mass of each sieve as percentage (mass passing mass / total mass x 100%) as the vertical axis E6% 9B% B2% E7% B7% 9A "Curved particle size cumulative curve graph was prepared, and the particle size through which 50% by mass passed was derived from the graph, and this value was taken as the average particle size.

[Low Density Particle Content] Since the particles floating in water have a density of less than 1.0 g / cm ³ , this volume is the amount of low density particles having an apparent density of less than 1.0 g / cm ³ . About 10 g of sample is put into a 200 ml graduated cylinder, water is added, and after stirring sufficiently, it is left to stand until the turbidity of water disappears, and the volume Vb of the floated sample Va and the sinked sample is measured and Va / (Va + Va ) Low density particle content was calculated from x 100 vol%.

[Residual density of high-density particles] The vol% of the total volume of the 45 μm sieve residual sample among the samples (apparent density of 1 g / cm ³ or more) sinking in water was measured.

[Example 1 (foaming step 1)]
Pearlite was manufactured by heating Pearlite A (average particle size 150 μm, ig.loss 2.3%) to the temperature shown in Table 1. Table 1 shows the firing temperature, the bulk density of the manufactured pearlite, and the content of low density particles having an apparent density of less than 1.0 g / cm 3. The A2 sample is a general pearlite with an overall bulk density of 0.2 g / cm ³ heated at 800 ° C. in an air flow firing furnace, and contains low density particles with an apparent density of less than 1.0 g / cm ^3. The amount is 79 vol%.

[Example 2 (foaming step 2)]
Pearlite B1 (average particle size 150 μm, ig.loss 3.5%), Pearlite B2 (average particle size 150 μm, ig.loss 3.0%), Obsidian B3 (average particle size 150 μm, ig.loss 0.9%) The pearlite was manufactured by heating to the temperature shown in Table 1. Table 2 shows the firing temperature, the bulk density of the manufactured pearlite, and the content of low density particles having an apparent density of less than 1.0 g / cm 3.

Example 3
For A2 produced in Example 1, high-density particles (particles having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more) are prepared by adjusting the wind speed (air pressure) of the foamed particles under the wind force of pneumatic transportation. Was dropped and separated.
Specifically, using a pneumatic transport pipe (inner diameter 200 mm), a trap part with a length of 200 mm is installed at the lower part of the pipe, passing through it by changing the wind speed, and collecting high-density particles by dropping them into the trap. did. The results are shown in Table 3.
In addition, about C1, since the wind speed was weak, separation amount became 30 vol% or more, and since it exceeded the capacity | capacitance to isolate | separate, separation was impossible. On the other hand, when the wind speed exceeds 50 m / sec, the separation amount becomes extremely small as 0.9 vol%, and the content of the high density particles is out of the scope of the present invention.

Example 4
A2 produced in Example 1 was put in water to separate the floating portion and the sedimented portion, and the floating portion was collected and dried to separate particles having an apparent density of 1.0 g / cm ³ or more. The results are shown in Table 4.

Example 5
Samples C2 to C4 of Example 3 and Sample D1 of Example 4 were pneumatically transported at a wind speed of 50 m / sec. Moreover, the same test was done about the sample A1-A2 of Example 1 which does not isolate | separate a high density particle as a comparative sample, Sample B1, B2, B3 of Example 2, and Sample C5 of Example 3. Table 5 shows the bulk density and the bulk density difference before and after pneumatic transportation. It is preferable that the bulk density after air transportation does not become heavier than 0.2 g / cm ³ compared with before transportation.
Even if the separation operation is not performed, if the remaining amount of high-density particles is less than 15 vol%, the bulk density difference is small even after transportation (A3). When the separation operation is performed, if the remaining amount of the high density is less than 15 vol%, the bulk density difference after transportation becomes 0.2 g / cm ³ or less, and the impact property becomes high (C2 to C4, D1).
When the apparent density is less than 0.2 g / cm ³ , the foaming ratio is high, the strength is weak, and the bulk density after transportation is high (B1) despite the low high-density particle content.

Claims (5)

It is a pearlite made by heating and foaming mineral raw materials, contains 80 vol% or more of low density particles with an apparent density of less than 1.0 g / cm ³ , has a particle diameter of 45 μm or more, and an apparent density of 1.0 g / cm ³ or more. An impact-resistant pearlite having a high-density particle content of 15 vol% or less , further containing particles having an apparent density of 1.0 g / cm ³ or more and a particle diameter of less than 45 μm . Impact perlite average apparent density according to claim 1 which is 0.2 to 0.6 g / cm ^3. After the mineral raw material is heated and foamed, it contains 80 vol% or more of low density particles having an apparent density of less than 1.0 g / cm ³ , and has a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more. In order to include particles having a particle content of 15 vol% or less and an apparent density of 1.0 g / cm ³ or more and a particle diameter of less than 45 μm , the particle diameter is 45 μm or more and the apparent density is 1.0 g / cm ³ or more. Of producing impact-resistant pearlite that separates high-density particles. The impact resistance according to claim 3, wherein the foam particles are classified by dropping high density particles having a particle diameter of 45 µm or more and an apparent density of 1.0 g / cm ³ or more by adjusting the wind speed to 10 to 50 m / sec under wind force. Method for producing pearlite. A method of separating high-density particles having a particle diameter of 45 μm or more and an apparent density of 1.0 g / cm ³ or more by separating the settled particles by placing the foamed particles in water after the mineral material is heated and foamed. 3. A method for producing an impact-resistant pearlite described in 3.