JPS5814373B2 - Manufacturing method of lead glass - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing lead glass, and more particularly, the present invention relates to a method for producing lead glass, and more particularly, it prevents segregation of a mixture of silicon dioxide and lead oxide during transportation or in a furnace, and also achieves a relatively low melting temperature. This invention relates to an improved method for producing lead glass with relatively short residence times in the furnace.

Traditionally, lead glass has been widely used in various glass products such as various types of glass for tubes, optical glass, and cut glass, and those with high lead content have been widely used as lead additives in the ceramic industry for the above-mentioned glass products and various types of glazes. ing.

When producing these lead glasses, silicon dioxide raw material powder and lead oxide raw material powder are weighed, dry blended, and then placed in a melting furnace.

However, lead oxides such as litharge and red lead have a significantly lower specific gravity than glass components such as silica sand, and are generally fine powders, so it is difficult to transport the mixture or put it into a melting furnace after mixing. There is a strong tendency for segregation to occur during
This has the disadvantage that the glass composition is often inhomogeneous.

Due to this segregation tendency and the slow progress of the reaction between lead oxide and silicon dioxide, there is a thermoeconomic problem in that homogeneous lead glass cannot be obtained unless the melting reaction is carried out at high temperatures and for an extremely long time. and unavoidable disadvantages in productivity.

Among various lead oxides, the present inventors selected wet-processed lead monoxide having the characteristics described in detail below, and added wet-processed lead monoxide and silicon dioxide as essential components to the wet-processed lead monoxide and silicon dioxide prior to melting. When the mixture is mixed in the presence of water, the segregation phenomenon described above is eliminated when the mixture is transferred or introduced into the furnace, and furthermore, lead glass can be produced at a relatively low temperature and short residence time in the furnace. I came across this.

That is, an object of the present invention is to provide an improved method for producing lead glass in which the tendency for segregation that occurs when a mixture of lead oxide and silicon dioxide as an essential component is charged into a furnace is effectively eliminated.

Another object of the present invention is to provide a method that is superior in thermoeconomic efficiency and productivity and can produce lead glass at a relatively low temperature and short residence time in a furnace, compared to conventional methods for producing lead glass. It is on offer.

Still another object of the present invention is to provide a method for producing lead glass using wet lead monoxide as lead oxide.

Still another object of the present invention is to provide a method for manufacturing leaded ceramic cuttings made of high lead content lead silicate glass economically and at high production rates.

According to the present invention, in the method for producing lead glass, which comprises melting and reacting a mixture containing silicon dioxide and lead oxide as essential components, prior to melting, 8.
Lead monoxide and silicon dioxide having a true density of 3 to 9.2 g/cc, an average particle diameter of 0.2 microns or less, an infrared absorption peak at a wave number of about 1400 to 1410 cL-1, and a chromic anhydride reactivity of a coefficient of 94 or higher. and PbO:SiO2 at a weight ratio of 2:98 to 92:8 and in the presence of water, or dry mixing and then contacting with water is provided. .

The lead monoxide used in the present invention is disclosed in U.S. Patent No. 4,1
No. 17,104, in which granules of metallic lead, a liquid medium such as water, and oxygen are filled in a rotary mill, and at least a portion of the granules of metallic lead are moistened with the liquid medium. The rotary mill is rotated under conditions in which the particles of lead monoxide are located in the gas phase above the liquid surface of the liquid medium and the particles of metallic lead rub against each other. manufactured by forming a dispersion in which the

This wet process lead monoxide has an extremely fine particle size due to the fact that the ultra-thin film layer of lead oxide formed on the surface of the metal lead particles is peeled off and becomes lead monoxide particles. The average particle size is less than 0.2 microns, especially in the range from 0.01 to 0.05 microns.

In this specification. The number average particle size means the number average value of the maximum particle size obtained by electron microscopic observation.

Furthermore, this lead monoxide has several special features that are not allowed in conventional lead monoxide, such as yellow
low modification) orthorhombic PbO
is a red-faced tetragonal PbOn9 with a density of 9.63 g/cc.
．． In contrast to the density of 34 g/cc, this wet method lead monoxide has a density of 8.3 to 9.2 g/cc, which is even lower than conventional yellow and red lead monoxide. Infrared rays (IR
) has an absorption peak.

Furthermore, this wet-processed lead monoxide has a fine particle size and is highly reactive because it has not been subjected to a thermal history such as calcination. Has a chromic acid reaction rate.

Here, the chromic anhydride reaction rate (RC) is defined as A
C is the determination of Cγ03 in the product (lead chromate) obtained by reacting lead monoxide and chromic anhydride at a molar ratio of 1:1 in water at a temperature of 60 to 70°C in the absence of a catalyst. It is the analytical value (g), and TC is the Cγ0 that should be contained in the product.
This is the theoretical value (9) of 3, that is, the amount of chromic anhydride added.

It is a value defined by , and it means the extent to which solid lead monoxide particles completely react with acid in their original form.

According to the present invention, the above-mentioned wet process lead monoxide powder and silicon dioxide powder are mixed in the presence of water prior to melting.

This mixing treatment effectively eliminates the segregation tendency often observed in mixtures of lead oxide raw materials and silicon dioxide powder, and allows homogenized lead glass to be obtained by melting at a relatively low temperature and in a short time. .

The segregation tendency of a mixture (batch) for producing lead glass is expressed by the following formula, where C is the average concentration (by weight) of lead monoxide (PbO) in all samples of the mixture placed on the trough-like inclined plate of the vibrator. After the vibrator is vibrated for a predetermined period of time, the mixture sample moves down the trough-like inclined plate, and the lead monoxide (PbO) in the sample is divided and collected in a tray at the bottom of the inclined plate. Average concentration (
weight).

It can be determined by comparing the vibration distribution ratio (Dx) defined by .

When the mixture shows no segregation tendency at all, the vibration distribution ratio of the divided and collected sample due to each vibration movement is O (zero), and when the segregation tendency is significant, this vibration distribution ratio (Dx) has a large value. Show numerical value.

Commercially available lead monoxide, that is, zinc oxide obtained by the lead powder method (
Yellow or red lead monoxide (Resurge) or Komyotan (Pb3) obtained by firing Pb20) in an oxygen atmosphere.
04) A composition obtained by dry mixing powder and silicon dioxide powder was used in a comparative example of Examples 1 and 2 (sample number H-
1. H-3, H-4, H-5 and H-6), the vibration distribution ratio (Dx
) indicates a value such that Dx>15b, especially Dx>20.

In addition, the composition powder obtained by mixing lead monoxide and silicon dioxide in the presence of water using the dry method described above also has a vibrational distribution ratio (Dx
) is slightly improved, but it is not satisfactory in that it shows a vibration distribution ratio such that vermilion Dx>10.

On the other hand, in the composition according to the present invention in which ultrafine lead monoxide particles and silicon dioxide powder are mixed in the presence of water by a wet method, any layer portion separated by vibration movement can be recovered. , the vibration distribution ratio (Dx) becomes a value satisfying DX<10, especially Dx<6.5, and the segregation tendency is effectively eliminated.

In the present invention, the exact reason why the segregation tendency is effectively suppressed by using wet process lead monoxide and mixing it with silicon dioxide in the presence of water is still not fully clear. However, according to the research conducted by the present inventors, the fine particles of wet-processed lead monoxide have the characteristic of being strongly positively charged in water, and when this dispersion is subjected to electrophoresis, the cathode plate There is a tendency for the deposits to be deposited in a very dense manner.

On the other hand, it is well known that iron dioxide powder tends to be negatively charged.

Thus, when wet lead monoxide and silicon dioxide are mixed in the presence of water, an electrostatic coating structure is formed in which the silicon dioxide particle surface is uniformly coated with lead monoxide fine particles, and this electrostatic Even when a large amount of wet lead monoxide is present in the coating structure, it is recognized that the coating structure exists in a very familiar state.

Thus, in the present invention, the effect of suppressing the segregation tendency of the raw material mixture can be explained.

In the present invention, the wet process lead monoxide and silicon dioxide as essential components can be blended in a wide range of weight ratios, that is, generally PbO:SiO=2:98 to 96:4.

The suitable blending ratio also differs depending on the intended use of the lead glass.

For example, Pbo:Si0 is used as a lead additive for ceramics.
The weight ratio of 2 is preferably selected in the range of 60:40 to 93:7, especially 70:30 to 93:7, and 97.6:2.4 to 68.1:31 for X-ray shielding glass applications. .9 especially 95:5
70:30 for optical glass applications, 5:95 to 60:40 especially 7:93 to 50:50, 4.3:95.7 to 76:24 for tube glass applications, especially 20:80 to 70 It is best to choose a range of :30.

In addition to the above-mentioned lead oxide component and silicon dioxide component, the raw material mixture used in the present invention can contain other raw materials or auxiliary raw materials used in the production of lead glass.

As such raw materials or auxiliary raw materials, for example, yNa20
, K20 and other alkali metal components, CaO, MgO, Ba
Alkaline earth metal components such as O and SrO. ZnO, B20
3, P205 and/or A1203 components, foam cutting, color erasing cutting, colored cutting, etc.

For foam cutting, sodium chloride, potassium chloride, sulfur sulfate, barium sulfate, etc. are used. For decolorizing, arsenite, cerium oxide, etc. are used. For colored cutting, cobalt oxide, copper oxide, nickel oxide, chromium oxide, etc. are used. , cadmium oxide, cadmium sulfide, selenium, tellurium, gold, silver, uranium, etc. are used.

In the present invention, even when the above-mentioned alkali metal components, alkaline earth metal components, etc. are used as auxiliary raw materials, the properties of wet process lead monoxide are not lost, as shown in Example 3 below, and the raw material mixture is The effect of suppressing the segregation tendency of can be maintained as it is.

In the present invention, the aforementioned lead monoxide and silicon dioxide are mixed in the presence of water.

The water is used in an amount sufficient to form a composition with reduced tendency to segregate with lead monoxide and silicon dioxide, which amount is generally equal to the total amount of lead monoxide and silicon dioxide. In contrast, the amount is at least 3 parts by weight, especially 5 parts by weight or more.

This moisture may be provided in the form of a lead monoxide deposit, such as a lead monoxide wet cake or slurry, or it may be provided as a silicon dioxide deposit.

Of course, if lead monoxide and silicon dioxide are both dry powders, they may be added separately to the mixed system.

If the amount of water present during the mixing of lead monoxide and silicon dioxide is less than 10 parts by weight, especially less than 5 parts by weight, based on the total amount of both, the resulting mixture will appear dry and fluid. Since this mixture is a powder or granule,
5. Then, it can be put into a furnace for vitrification.

Of course, if the resulting mixture has a moisture content above the above-mentioned range, the mixture can be subjected to a drying operation to form a dry, flowable powder or granules.

Note that water can be used either in liquid form or in steam form.

For example, in order to mix both in the presence of water vapor, water vapor may be caused to exist in the mixing system by blowing water vapor into the mixing system.

Of course, in this case, there is no problem even if liquid water and water vapor coexist in the mixing system.

Mixing of lead monoxide and silicon dioxide can be carried out using any stirring mixer.

However, when mixing in the presence of a relatively small amount of water as mentioned above, a stirring mixer of the type that stirs both powders while lifting them upwards is required. The use of a stirrer that is more voluminous is particularly advantageous for the purposes of the invention, since it results in a mixture with a particularly low tendency to segregate as described above.

In the present invention, it is advantageous in terms of operation to mix both in the presence of water. A similar effect is achieved when objects come into contact with water.

In order to bring water into contact with the mixture, methods such as spraying water onto the mixture or exposing the mixture to water vapor may be employed.

In this case as well, it is desirable to maintain a water content of 3 parts by weight or more, particularly 5 parts by weight or more per whole.

When putting it into the melting furnace. Or when it comes into contact with combustion gas,
The mixture of lead monoxide and silicon dioxide can also be formed into granules to prevent dust carryover.

For example, molding into granules can be carried out using various molding methods depending on the amount of water contained in the mixture, such as transfer granulation method, tableting granulation method, extrusion granulation method, mixed granulation method, spray granulation method, etc. A flaking granulation method or the like can be used, and the particle size of the granules is O. O5l! It can be varied within a range of 50 inches to 50 inches.

In the present invention, the melting and reaction of the mixture containing the silicon dioxide raw material and lead monoxide can be easily carried out by means known per se.

The temperature and time of this melting/reaction vary significantly depending on the blending ratio of both raw materials, types, and intended use, and are difficult to define unconditionally.

However, generally speaking, 650 to 1500℃,
In particular, appropriate conditions may be selected depending on the application, from among a temperature of 850 to 1200° C. and a treatment time of 3 minutes to 10 days.

However, according to the method of the present invention, by subjecting the mixture obtained by the method described above to a melting reaction, lead glass can be produced at a lower temperature and in a shorter processing time than when conventional lead monoxide is used. It becomes possible to manufacture.

For example, in the case of lead glass cullet used as a lead additive for ceramics, a melting temperature of 700°C or higher is required when using conventional dry method lead oxide compared to the same weight ratio of PbO:Sin2. However, when using the mixture produced by the method of the present invention, this temperature can be lowered to about 685°C, and the homogeneity of the obtained glass (this is a problem described in Japanese Patent Publication No. 51-126) It has been experimentally confirmed that the homogeneous component ratio (DH) is more advanced.

In the present invention, among the above-mentioned wet method lead monoate. Lead oxide, which is expressed as an acetic acid aqueous solution insoluble content and is more highly oxidized than lead monoxide, such as Pb304 or PbO2, is mixed with 0.
It is desirable to use wet process lead monoxide in an amount of 0.05 to 90 parts by weight, especially 1 to 85 parts by weight, to improve the hue of the lead glass.

Wet-processed lead monoxide, which has a relatively high content of aqueous acetic acid insoluble solution, can be produced by contacting metallic lead, liquid medium, and oxygen at a relatively high temperature such as 35 to 95°C in the above-mentioned manufacturing method. It can be easily obtained by practicing.

Oxidation through the wet wall on the surface of metal lead particles is, of course, an exothermic reaction, and this reaction heat is used to
It should be understood that wet process lead monoxide containing oxides with a higher degree of oxidation than button monoxide can be readily produced.

The lead glass according to the present invention can be used as lead additives for ceramics, X line-blocking glass, various crystal glasses, etc. depending on the lead content.
It is useful in various fields such as imitation jewelry glass, overglaze glass, and tube glass.

The invention is illustrated by the following example.

Reference example 1 As a method for producing lead oxide using a wet method, U.S. Patent No. 4,1
It was produced according to the method described in Japanese Patent No. 17,104.

That is, lead monoxide having a density of 8.3 to 9.4 g/CC, a number average particle diameter of 0.2 μ or less, an infrared absorption peak at a wave number of 1400 to 1410 cm, and a chromic anhydride reaction rate of 94% or more. The manufacturing method will be outlined.

Metal lead with a diameter of 2 to 7 mm (electrolytic lead purity 99, 99)
200cg of granules were processed using a rotary stainless steel tube mill (inner diameter 34.5m, length 130cm, internal volume approx. 120cm).
) and fill it with 30 liters of water and oxygen (2 kg gauge pressure), and by rotating this tube mill, a part of the metal lead moistened with water is released into the oxygen gas phase above the water surface. Pushed up by centrifugal force, the ultra-thin layer of water around the metal lead particles absorbs oxygen, producing lead monoxide, which is also produced when the metal lead particles rub against each other in the water. Ultrafine particles of lead monoxide are dispersed in water, with a concentration of Pb0335
A dispersion liquid (sample number p-ws) of 1/100 rl was obtained.

The wet lead monoxide slurry obtained here was filtered, then dried at about 80° C., and then pulverized to prepare a wet lead monoxide dry powder product (sample number P-WP).

The lead monoxide slurry recovered here was measured for its true density, number average particle diameter, composition of metallic lead components, etc., chromic acid reaction rate, infrared absorption spectrum, and X-ray diffraction, and the results are shown in Table 1. Also displayed.

In addition, each measurement method followed the method below.

(a) Fill a true density pycnometer with benzene solution and fill it with the weight (
W) and the temperature (Ti) with the provided thermometer.

Next, the benzene is discharged and the sample is collected in a predetermined amount (M(.Z
), further benzene was added, the mixture was placed in a vacuum desiccator, the pressure was reduced to 3 mmHl using a vacuum pump for 3 hours, the cock was closed, the vacuum pump was removed, and the temperature was brought to Ti and left overnight.

Open the cock, take out the pycnometer, fill it with benzene, measure the weight (W') and temperature (Ti), and calculate using the following formula (3).

ds: Sample density d: Ti Specific gravity of benzene at °C (b) Number average particle diameter sampled from 1,000 to 3,000
The size of 200 to 300 particles was measured at a magnification of 200 to 300 times, and the average particle diameter (μ
) was sought.

(C) Metallic lead content The acetic acid insoluble content, that is, the metallic lead content, was determined according to the method described in JIS K-1456 (Lissage quantitative method), and the content was expressed as one.

(d) Pour 500 l of water into a beaker with a chromic acid reaction rate of 2e, accurately weigh 69.06 g of lead oxide powder as a sample, boil it, and add it while stirring well to thoroughly disperse it in the water. , then this dispersion is heated to 65°C.

On the other hand, an aqueous solution of chromic anhydride prepared (30.949
/100ml water) while stirring, slowly add 3
The mixture was injected for 0 minutes, and further maintained at 65°C.
After stirring and aging for 60 minutes, the lead chromate crystals were filtered with P, washed with water, and the resulting lead chromate was aged at 110°C.
The amount of chromic acid fixed as lead chromate was quantitatively analyzed using the amount (g) of chromic acid anhydride (CrO3), and from this result, the amount of fixed chromic acid (CrO3) tp
) (AC) and the amount (g) (TC) of chromic acid (CrO3) of the raw material used, from the following formula (4), RC = AT / TCX100 (capital)...・
...(4) The chromic acid reaction rate (RC%) was determined.

(e) Infrared absorption spectrum measurement Using an infrared absorption spectrum measuring device manufactured by JASCO Corporation (IR-G type) under reduced pressure vacuum (3 mmHg) 400 ki/
Molded with a KBr tablet molding machine under cys pressure, 4.
The absorption spectrum was subjected to self-recording diffraction in the wavelength range of 000 to 400 cr.

In addition, the intensity of the diffraction peak of the absorption spectrum was expressed using the following six-level symbol.

VS: Strongest S: Strong M: Normal W: Weak b: Minute sh: Extremely small (f) X-ray diffraction measurement
tNo. 2001. The goniometer is a wide-angle CatN
o. 2227, Proportional Counter), and the sample was measured by the powder measurement method according to the following diffraction conditions.

Diffraction condition target Cu Filter Ni Voltage 30κ■ Current 15WA Count range 1000cps High voltage 1450V Time constant 1sec Chart speed l(1/min Scanning speed 1°/min Diffraction angle (2θ) 17° to 60.5° Slit width 1°-1°10,3 (g) Composition analysis of lead oxide The composition was analyzed in accordance with the method described in JIS K 1456 (Litharge quantitative method).

In this specification, aqueous slurries are often used as target samples, but unless otherwise specified, all compositions are expressed by weight on a dry matter basis.

(g-1) Lead monoxide (PbO) Weigh the sample accurately, measure the moisture content, and calculate the moisture content by (
If the sample was a powder, it was moistened with water beforehand.

) Add 6N acetic acid, heat to dissolve, cool, and adjust the pH of the sample solution to 5.0 with aqueous ammonia and buffer solution.
After titrating with EDTA (disodium ethylenediaminetetraacetate) solution at molar concentration using xynol orange as an indicator, lead monoxide (
The content of PbO) was determined on a dry matter basis.

(g-2) Komyotan (Pb304) After sampling in the same manner as in the case of -lead oxide in (g-1) above, the sample was dissolved in 6N acetic acid and sodium acetate, and then a certain amount of A sodium thiosulfate solution was added, and after a certain period of time, the starch solution was used as an indicator and back titration was performed with a 1-suzu normal iodine solution.
The content (1) of 04) was determined on a dry matter basis.

(g-3) Metallic lead (Pb) After sampling in the same manner as in the case of lead monoxide (g-1) above, 6N acetic acid was added and dissolved by heating, and at the same time, 1 molar concentration of hydroxylamine hydrochloride was added. Add a small amount of P to dissolve the lead peroxide compound present in the sample, then separate the sample with plain paper, wash with warm water, and wash until no lead component is detected in the washing solution. Transfer the residue to an Erlenmeyer flask, dissolve the metal lead on the paper with 6N nitric acid and 2 to 3 drops of 30% hydrogen peroxide, and then adjust the pH to approximately 5 using a buffer solution of aqueous ammonia and sodium acetate. The content of metallic lead (Pb) was determined on a dry matter basis by titration with an EDTA solution having a molar concentration of ζ and xylenol orange as an indicator.

(g-4) Impurities (Fe, Cu) After sampling in the same manner as in the case of lead monoxide in (g-1) above, nitric acid and hydrogen peroxide were added to dissolve, and evaporation to dryness was repeated. JIS K 012 sample preparation solution
0 Quantitate Fe (iron) and Cu (copper) in accordance with the "Atomic Absorption Spectrometry General Rules" and calculate the content on a dry matter basis (p
pm).

Reference Example 2 According to the method described in Japanese Patent Application No. 135909/1980,
Another method for producing lead monoxide using a wet method using zinc oxide powder as a raw material will be explained.

As the lead zinc oxide powder used as a raw material, dark gray-green lead zinc oxide powder manufactured by the Shimadzu lead powder method was selected.

The Shimadzu lead powder method is the same as that used in Reference Example 1, in which lead powder is produced by dry-pulverizing preformed metal lead grains in a rotary mill.
A lead zinc oxide powder with a bulk of 72 ml/g was recovered.

The zinc oxide powder is prepared into an aqueous slurry using water prior to entering the oxidation step.

At this time, the concentration of zinc oxide component in the aqueous slurry was 20g.
/100ml concentration.

Next, a liquid cyclone applying centrifugal force classification is used to classify and separate the coarse metallic lead powder contained in the raw material lead zinc oxide powder and the coarse particles of the lead zinc oxide powder, to form a homogeneous lead zinc oxide powder. An aqueous slurry was prepared.

The liquid cyclone used here had a diameter of 55 mmφ, a conical apex angle of 20°, an inlet of 8 mmφ, a downstream nozzle of 6 μmφ,
A stainless steel liquid cyclone with a discharge pressure of 1.8 kg/cr2 was used.

The composition of the aqueous slurry of homogeneous zinc oxide whose coarse particles were classified and separated using this liquid cyclone was 12.4 g/100 rl as a solid concentration, and the amount of metallic lead in this solid was 10. 5 was in charge of weight.

A contact method mainly using an aeration method was used to bring the homogenized aqueous slurry of lead zinc oxide into contact with molecular oxygen.

Next, a liquid cyclone was attached to separate and classify unreacted lead zinc oxide components after an aeration-type contact tower attached to a bubble column.

This liquid cyclone classifies and separates the unoxidized lead zinc oxide component remaining in the watermark slurry after the oxidation process, and the lead monoxide slurry (sample number p. -ss) was collected.

The watermark slurry recovered here has a PbO concentration of 18.
It was 49/100ml.

In addition, each item was measured in the same manner as in Reference Example 1, and the results are also shown in Table 1.

Reference example 3 The conventional dry method for producing lead monoxide is
It was manufactured according to the method described in Japanese Patent No. 7-11801.

First, a lead molding machine was used to mold a soldered lead ingot into a diameter 2.
5cm x length 2. After molding OCr into a cylindrical shape, the research report of Genzo Shimazu, Journal of the Japan Society of Mechanical Engineers, Volume 28 (No. 100)
), pages 489-516 (1925), metal lead is ground in a rotary mill using a dry grinding method in accordance with the so-called Shimadzu lead powder method described in Manufacture of lead powder.

Next, the recovered zinc oxide powder is placed in a rotary furnace, oxygen is added, and it is burned under stirring to oxidize it at a temperature of approximately 630 to 720 degrees Celsius, and the temperature rise due to the heat of combustion of the zinc oxide is measured. As soon as the temperature no longer rises due to combustion, it is rapidly discharged into a cooling chamber and cooled, yielding yellow granular lead oxide.

Next, this yellow granular lead oxide was crushed and classified using a gas cyclone method to prepare an orange yellow lead monoxide powder (sample number P-DP).

Example 1 As the lead glass composition, the weight composition of PbO and 8102 was selected as PbO:SiO2 of 85.0:15.0.

As lead monoxide (PbO) raw materials, three types of wet lead monoxide prepared by the method described in Reference Examples 1 and 2 (sample numbers P-WS, P-WP, and P-SS) were selected.

As the silicic acid (Si02) raw material, two types of refined silica sand powder for glass (sample numbers S-A and S-B) from Flattery, Australia were selected.

The analysis results (composition) and particle size distribution are shown in Table 2 below.

When blending and mixing the above raw materials, sample numbers p-ws and p-ss of the lead monoxide raw materials were subjected to over-dehydration as a pretreatment to form a wet cake.

The moisture content at this time was 20.1 parts by weight in the case of P-WS7, and 19.2 parts by weight in the case of P-SS7.

Each silicic acid (Si02
) powders were added at a predetermined ratio and mixed sufficiently homogeneously using a kneading stirrer, and then dried at 110 to 120°C to form a blended composition of lead additive for lead glass (sample numbers 1-1 and 1-5). ) Five types were prepared.

In the case of sample number P-WP of lead monoxide raw material, all the raw materials are dry powders, so after blending the two raw materials in a predetermined amount ratio, Add water equivalent to the amount of water, mix thoroughly and homogeneously to form a clay-like mixture, and then dry at 110 to 120°C to prepare a blended composition for lead cutting for lead glass (sample number 1-2). The composition and segregation tendency of the blended compositions of each of the lead additives blended here were measured as vibrational distribution ratios (Dx) using the test method shown below, and the results are shown in Table 3.

Composition analysis method: A sample (containing about 0.15 g of PbO) is accurately weighed into an evaporating dish, 5 L of 6N nitric acid is added thereto, and the sample is evaporated to dryness.

After repeating this evaporation to dryness three times, Toyo P Paper No. 3. Thoroughly perform separate washing using a rotor.

Transfer the washing solution to a 250Tl volumetric flask.

(1) Silicon dioxide (Si02) The silicon dioxide on the above-mentioned r paper was placed in a small porcelain crucible together with the r paper, dried at 110°C for 2 hours, and then roasted for 1 hour in a constant temperature electric furnace set at 800°C. After that, take out the crucible, let it cool down to room temperature in a desiccator, and weigh it (W,).
L, the Si02 content is determined using the following equation (5).

(2) Lead monoxide (PbO) Add water to the volumetric flask and cleaning solution up to the marked line to make a predetermined volume, and mix thoroughly to make a homogeneous solution.

Take 50 ml of this solution in an Erlenmeyer flask, add 10 l of 20% potassium sodium tartrate solution and shake, then add 1 liter of ammonia salt and 10 liter of ammonium buffer solution and shake thoroughly.

Furthermore, 1 ml of 2-functional potassium cyanide solution is added, 1 ml of Eriochrome Black T solution is added as an indicator, and immediately titrated with M/20-EDTA standard solution until the color changes from reddish-purple to sky blue.

Next, the lead content (PbO%) is calculated using the following equation (6).

(3) Potassium oxide (K20) Pour 1 ml of the homogeneous solution prepared in (2) into a 1000 ml volumetric flask, dilute it by adding water to the marked line, and shake thoroughly.

Using an atomic absorption spectrometer A-500 manufactured by Nippon Jarrell Atsushi ■, read the K20 minutes by comparing it with the K20 standard solution, divide the dilution factor by the weight of the sample, and calculate the K20 weight factor.

Method for Measuring Vibration Distribution Ratio (Dx) A predetermined amount of sample (9B!) is placed at point W1 on the inclined trough-like plate G of the vibrator described below (see attached drawing), and then for a certain period of time. The gutter-like plate is vibrated with a constant intensity using the Urus motor M, and the vibration moves the sample on the gutter-like plate from point W1 to point W2 and further to point W3, causing it to fall below the gutter-like plate. , when the sample that has fallen into the tray of P1 reaches one-third of the total sample, that is, 30 g, the tray is replaced with another tray P2, the fallen sample is collected, and the sample that has fallen into the tray of P1 is collected. The sample that fell into the saucer is one-third of the total sample, that is, 3
The vibration was stopped when the sample reached 0 g, and at this time, the sample remaining on the gutter-like plate, that is, 30 g, which is one-third of the total sample.
The sample was collected in another saucer P3.

In this way, the sample on the trough-like plate is moved by vibration while spreading out on the slanted trough-like plate. For the divided samples (S1, S2 and SS) that were dropped below the plate and divided into three equal parts, each lead oxide concentration Lx (Lx is the PbO content coefficient L1, L2 and L3 in each divided sample)
shows.

) was determined, and the ratio (ratio) of segregation of the compound composition caused by movement due to vibration to the lead oxide concentration L (PbO content coefficient) (Lψ = L1 + L2 + L3) in the entire sample was determined using the following formula C force. -Lx1oo... (7) Next, in order to know the segregation tendency of the compound composition of each sample, the vibrational distribution ratio Dx was determined using the following formula (8).

Dx=lEx-100I-{8) The vibrator is designed so that the vibrations generated by the Uras motor M are transmitted through the spring to the stainless steel gutter-like inclined plate G installed at the top with an inclination of 5 degrees. By turning on the switch of the motor M, the vibration starts, and the sample vibrates and moves toward the lower side of the trough-like inclined plate G, so that it is received by the tray P provided at the bottom of the inclined plate G. I made it.

The vibrator is made by Shinko Electric (CI-2 type), and the capacity of the Eurus Motor M is 50 cycles, 1.25A, and 200cm.
was used to generate vibrations at a frequency of 3000 times/min.

The stainless steel gutter plate G had a width of 15 Cr, a length of 60 Cr, a side wall height of 10 Cr, and a plate thickness of 1 mm.

Next, the blended composition of each lead additive prepared here was vitrified to form a cullet-shaped lead, that is, 920 to 100
500k from the inlet end of the electric furnace maintained at a temperature of 0℃
The melt is supplied at a rate of 9 Anr, and the same amount of melt as the supplied amount is taken out from the discharge end of the electric furnace, and the average residence time in the furnace from the introduction end to the discharge end is maintained for about 20 minutes.
The bright red molten material taken out from the discharge end of this furnace was directly poured into water to form irregularly shaped grainy cullet waste, which was then drained and dried to produce current lead additives for the ceramics industry. .

Here are the current lead cuttings for ceramics that we collected.
The average composition and particle size are divided into 3 stages (16 meshes (1170
The composition of each division was analyzed, and the results are shown in Table 3.

In addition, in order to clarify the present invention, for the following four types of comparative examples, a blended composition of a lead additive was prepared, and the composition was further melted to prepare a current lead cutting.

As lead monoxide (PbO) raw materials, wet and dry lead monoxide (sample numbers P-WP and P-DP) prepared by the methods described in Reference Examples 1 and 3 were selected.

As the silicic acid (St02) raw material, the same refined silica sand powder for glass produced by Flattery as mentioned above was selected.

The blending ratio is the same as above <PbO:Si02 is 85:
The weight ratio was chosen to be 15.

When blending, for sample number H-1, sample number P-DP was selected using the dry method as lead monoxide, and a dry blending method was adopted in which the powdered products of both raw materials were stirred and mixed as they were, resulting in a homogeneous composition. It became a thing.

In sample number H-2, water equivalent to 10 parts by weight was added to the blended composition of sample number H-1, kneaded, and then dried to obtain a homogeneous composition.

For sample number H-3, sample number p-wp was selected using the wet method as the lead monoxide raw material, and in the same manner as in the case of sample number H-1 above, a homogeneous material was obtained by the dry blending method without using water. It was made into a composition.

Furthermore, in sample number H-4, the commercially available reagent Komyotan (
Pb304), and as in the case of sample number H-1,
It was mixed with silica sand powder by stirring to form a homogeneous composition.

The compositions and vibrational distribution ratios of the four comparative samples were also measured in the same manner as above, and are also shown in Table 3.

Furthermore, in the same manner as above, the four blended compositions of this comparative example were melted in an electric furnace maintained at a temperature of 920 to 1000°C, and then currented in water to a grainy state, drained, After drying, it was made into ceramic lead cutting, and its average composition and composition for each particle size were measured, and the results are also shown in Table 3.

As a result of the above, wet Resurge was used as a lead component raw material. Even if the mixed composition obtained by homogeneously mixing with silicic acid powder in the presence of water and then drying it is moved while applying vibration using a vibrator, the composition does not change as seen in the vibration distribution ratio. , almost no compositional segregation was observed, whereas when Lissage and Komyotan were mixed with silicic acid powder in a dry process as in the conventional method (Comparative Examples H-1 and H-4), the vibration machine When it is moved by applying vibration, the composition of the 1Pb is severely segregated.
The O concentration is segregated from 85.0% to 98%, and it is easy to understand that if these raw materials are put into a furnace and vitrified as they are, a compositionally heterogeneous glass will be produced. Ru.

This is the same even when wet litharge is used as the raw material for the lead component and when it is mixed without the presence of water (Comparative Example H-3), and the tendency of composition segregation is large.

In addition, even if water is used during mixing, as in the case of wet litharge, when litharge with a high reactivity (chromic acid reaction rate of 94 or higher) is not used (comparative example H-2), the tendency of composition segregation is also large. .

These phenomena are caused by the presence of ultrafine particles and easily reactive lead monoxide, i.e., when wet resurge is used, the presence of water at the time of mixing [, V].
This is thought to be due to the beginning of bonding between and SiO2.

This means that the composition after mixing (sample numbers 1-1 to 1-
5) can also be understood from the fact that compared to the comparative example, the litharge color was reduced and the color changed to a pale lead silicate color.

It is well understood that when glass is manufactured from raw materials with a low tendency to segregation in the raw material blend, glass with a suitably homogeneous composition can be easily obtained, and that this is effective in manufacturing lead glass. be done.

Furthermore, when blending raw materials, lead oxide, a compound of lead that is harmful to the human body, is handled in a wet state rather than in a dry state, where dust is likely to be generated, which eliminates problems in the working environment and eliminates pollution problems. It is also understood that there are great benefits to being able to use.

Furthermore, it is also understood that in the dehydration and drying of wet resurge, a compound such as silicic acid is added before drying, so there is an advantage that the drying process can be performed easily.

Example 2 Lead glass compositions include PbO, SiO2 and K20
PbO 2 was selected so that the weight composition of
2.5 (weight) Si02 67.5 K20 10.0 As a lead monoxide (PbO) raw material, wet lead monoxide (sample number P-WS.P) prepared by the method described in Reference Examples 1 and 2 was used. -WP and p-ss) were selected.

As the silicic acid (Sin2) raw material, as in Example 1, two types of refined silica sand powder for glass produced from Flattery, Australia (sample numbers S-A and S-B) were selected.

As the potassium oxide (K20) raw material, a commercially available reagent potassium nitrate (KNO3) powder that passed through a 100 mesh sieve was selected.

When mixing the above raw materials, sample number p of lead monoxide raw material
-ws and p-ss, Sl02 powder and K were added to the aqueous slurry as it was at each concentration.
After adding NO3 powder in a predetermined amount and mixing thoroughly and homogeneously in the form of a paste, it was dehydrated and dried by evaporation to dryness while stirring to obtain raw materials for lead glass (sample numbers 2-1 and 2-1). 2-4) was blended.

In the case of sample number P-WP of lead monoxide raw material, all the raw materials are dry powders, so after blending the three raw materials in advance at a predetermined ratio, it is equivalent to 11 weight ratios for this blended raw material. Water was added thereto, and the mixture was thoroughly mixed in a cross-wire configuration, and dried at 1,100 to 120° C. to form a clay-like material, and a lead glass raw material (sample number 2-2) was blended.

In addition, in the case of wet Resurge dry powder (sample number P-WP), after dry blending with other silica and potassium nitrate in a predetermined ratio, the resulting powder mixture is
It was placed in a commercially available cloth bag made of synthetic fibers and hung in an autoclave that enabled the generation of steam.
After heating under pressure at ℃ for about 30 minutes, the blended composition (sample number 2-
3) was prepared.

In addition, this blended product contained 3.5% as water.

Regarding the four types of lead glass raw material compounding compositions respectively blended in Example 1, the segregation direction was measured by the vibration distribution ratio (equity) in the same manner as in Example 1, and the results are shown in Table 4. displayed.

As a comparative example, two types of lead oxide raw materials were used: dry litharge powder (sample number P-DP) and wet litharge dry powder (sample number P-WP).
In the same manner as in this example, silica and potassium nitrate were mixed and blended without using water during blending to prepare blended compositions for button glass (sample numbers H-5 and H- 6) For these two types of comparative examples, the vibration distribution ratio was determined in the same manner as in this example. The results are also shown in Table 4.Next, the raw material blend compositions blended by each method (
(Comparative Example) was placed in an alumina crucible, and the temperature was 1400-150.
It was vitrified in an electric furnace maintained at 0° C. for 1 hour, and slowly cooled for 24 hours to produce a lump of lead glass.

The PbO content in each lump of lead glass produced in this case was analyzed, and the results are also shown in Table 4.

As a result of the above, a compounded composition obtained by mixing and blending silica and potassium nitrate in the presence of water using wet lead monoxide as a raw material, and then drying it, is different from a compounded composition obtained by dry-mixing without the presence of water ( It is well understood that the segregation tendency (vibration distribution ratio) when moved by a vibrator is also smaller than that in Comparative Example), and that even if lead glass is used, homogeneous lead glass can be obtained.

In addition, as shown in this example (sample number 2-
3) It is understood that lead glass can also be suitably produced when a dry mixed powder composition is taken out into a steam atmosphere and vitrified as it is in the presence of a small amount of water.

Example 3 In various formulations of lead glass, various raw materials were blended in advance in the presence of water using wet ultrafine particle lead monoxide as the lead ingredient raw material, and after drying, melted to produce various lead glasses. Let me explain the case.

As the wet lead monoxide, powder with sample number P-WP was selected, and as the silicic acid, purified silica sand powder (sample number S-A) from Fratari, which was selected in Example 1, was selected.

All other raw materials were selected from commercially available reagents such as carbonates, sulfates, nitrates, or oxides, respectively.

The blending ratio of each raw material was selected according to the weight ratio shown in Table 5, and the amount of water used in the blending was also shown in Table 5.

The mixing method was the same as in the case of sample number 1-2 in Example 1, and each was mixed homogeneously in a kneaded state, then dried, and 8 types of each (sample number 3-1, . . .・・・・・・
... A blended composition of 3-8) was prepared.

In order to understand the segregation tendency due to vibration of each blended composition prepared in this 5, the vibration distribution ratio was measured (and the results are also shown in Table 5).

Next, each blended composition was placed in an alumina crucible, melted in an electric furnace, and then slowly cooled to form each lump of lead glass.

The Pb0 content of each lead glass ingot was analyzed, and the results are also shown in Table 5.

As a result, in the case of any of the typical compositions of lead glass, in the presence of water using wet lead monoxide as a raw material,
By kneading and blending in advance and making it a dry product, there is almost no segregation in the composition even when the composition is vibrated with a vibrator, making it a good blend for producing homogeneous lead glass. Something is well understood.

[Brief explanation of the drawing]

Fig. 1 is a side view of a vibrator used to measure the vibration distribution ratio, and Fig. 2 is a perspective view showing the dimensions of a gutter-like plate G on this vibrator.

Claims (1)

[Claims] 1. In a method for producing lead glass, which comprises melting and reacting a mixture containing silicon dioxide and lead oxide as essential components, 8.3 to 9.2 g of lead glass is added prior to melting.
/cc true density, number average particle size of 0.2 microns or less,
Lead monoxide and silicon dioxide, which have an infrared absorption peak at a wave number of about 1400 to 1410 cx-1 and a chromic anhydride reaction rate of 94 coefficients or more, and silicon dioxide are mixed in a weight ratio of PbO:SiO2=2:98 to 96:4 and water. 1. A method for producing lead glass, which comprises mixing in the presence of water or dry mixing and then contacting with water. 2. The method according to claim 1, wherein the lead monoxide and silicon dioxide are mixed in the presence of water in an amount of 3 or more parts by weight based on the total amount of the lead monoxide and silicon dioxide. 3 After dry mixing the lead monoxide and silicon dioxide,
This admixture was exposed to a steam atmosphere to
2. A method according to claim 1, which comprises retaining more than a weight factor of water. 4. A method according to claim 1, wherein the mixture described above is formed into granules prior to melting.