JPS5920631B2 - Ceramic base consisting of amorphous lead titanate and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel ceramic base made of substantially amorphous lead titanate and a method for producing the same, and in more detail (this includes dielectric ceramics, piezoelectric ceramics, resistive ceramics,
This invention relates to a new ceramic base made of lead titanate useful as semiconductor ceramics, etc., and a method for producing the same.

Lead titanate is widely used as the porcelain material for electronic components mentioned above, but the most common manufacturing method for synthesizing lead-containing double oxides is to combine lead oxide and titanium dioxide components at high temperatures. It consists of an oxide method that involves a solid phase reaction.

However, when the product obtained by such a solid phase reaction is subjected to X-ray diffraction, an X-ray characteristic peculiar to lead titanate is detected.
In addition to the ray diffraction pattern, it shows an X-ray diffraction pattern peculiar to the raw materials lead monoxide and titanium dioxide, and has the disadvantage of being extremely heterogeneous in composition.

Furthermore, the double oxide obtained by this solid phase reaction method has a particle size that is low and lacks intimate miscibility with other raw materials and auxiliary raw materials due to the fact that it has been subjected to thermal history at high temperatures. , reactivity (both have the disadvantage of being inferior).

In order to improve the above-mentioned drawbacks in solid phase reactivity, it is already known to produce lead titanate by a solution method.

A typical method is to convert titanyl nitrate etc. into lead nitrate, as described in U.S. Pat. No. 3,352,632.
A water-soluble lead salt such as lead acetate and oxalic acid are reacted in an aqueous medium containing oxalic acid to form a composite oxalate, and this composite oxalate is thermally decomposed at a temperature of 700°C or higher to produce lead titanate. It consists of getting.

In this method, lead titanate is produced at a temperature of 700°C.
Heating at such high temperatures accelerates particle growth, which inevitably leads to coarsening and non-uniformity of the particle size of the target product.

Furthermore, Japanese Patent Publication No. 18679/1983 (in which hydrogen peroxide is added to a solution containing a water-soluble titanium salt such as titanium tetrachloride or titanium nitrate, and a water-soluble lead salt such as lead nitrate) In both cases, a complex peroxide is precipitated by adding an alkali such as ammonia to maintain the pH at 3 or higher, and this complex peroxide is hydrolyzed at a temperature of 100°C or higher to produce amorphous lead titanate. Sukoyoshi is disclosed.

This method achieves the advantage of obtaining a relatively homogeneous amorphous lead titanate at a relatively low temperature, or this amorphous lead titanate has a very porous gel morphology, and the ceramic It is still not fully satisfactory for use as a raw material.

The present inventors selected lead monoxide (hereinafter sometimes simply referred to as wet method - lead oxide) proposed by the present inventors in U.S. Patent No. 4,117,104 as a lead component raw material, Furthermore, when titanium oxynitrate or its hydrolyzate is selected as the raw material for the titanium component, these two components easily react to form amorphous lead titanate having novel particle size characteristics and crystallization characteristics. We have also discovered that this amorphous lead titanate is extremely useful as a ceramic base.

That is, according to the present invention ζ, 8.3 to 9.2 i /c
True density of c, primary particle size less than 0.2 microns, wave number 1
400 to 141. Lead monoxide having an infrared absorption peak at ``Ocrrt-'' and a chromic acid anhydride reaction rate of 94% or more, and titanium oxynitrate or its hydrolyzate are combined in a molar ratio of P b O: T + 02 of 6. There is provided a method for producing a ceramic base comprising amorphous lead titanate, characterized in that the reaction is carried out in an aqueous medium at a ratio in the range of 1:1 to 1:1.1.

The invention further provides that the molar ratio of PbO:TlO2 is between 621 and 1:1. range ρ is comprised of substantially amorphous lead titanate, which is comprised of fine particles having an apparent particle size of 5 μm or less and a crystallization temperature of 500 to 600° C., and said fine particles are aqueous. The slurry is dehydrated under reduced pressure and then calcined at 600°C. The molded product has a mercury porosimetry pore volume of 0.2 m17ji or less (
A ceramic base is provided which is characterized by a pore radius of 430~], 4.7X104[lambda]).

The lead titanate for ceramics of the present invention is amorphous and has a
It has the characteristics of being composed of fine particles having an apparent particle size of 2 .mu.m or less and a crystallization temperature of 500 to 600.degree. C.

The lead oxide-titanium oxide coprecipitate obtained by the oxalic acid method or peroxide method described above is essentially amorphous, but all such conventional coprecipitates are in the form of a gel. The dried product has a grain size similar to that of silica gel.

On the other hand, the lead titanate according to the present invention is amorphous because it is formed by direct reaction between the solid particles of lead oxide and the titanium component in a wet process which has extremely fine particle size and is highly reactive. However, it does not exhibit the cohesive continuous phase characteristic of gel-like substances, and takes the form of non-cohesive, dense fine particles.

Incidentally, the fact that the lead titanate according to the present invention ζ is amorphous and non-agglomerated fine particles is shown in the X-ray diffraction diagram of FIG. 1 and FIGS. 2-A-1 and 2-A- This will be easily understood by referring to the optical micrograph in Figure 2.

Itto, peroxide method [Is the coprecipitated lead titanate also amorphous in X-rays as in the present invention? The fact that it has a shape peculiar to an amorphous gel-like substance is easily understood by referring to a microscopic photograph.

Furthermore, the fact that the amorphous lead titanate according to the present invention (in which the lead oxide component and the titanium oxide component are present in a very homogeneous form and has the characteristics of being extremely easy to crystallize) The crystallization temperature of lead titanate is significantly lower than that of conventional amorphous lead titanate, in the range of 500 to 600°C (as is clear from this report).

Curve A in FIG. 3 is a differential thermal analysis (1) TA) curve of amorphous lead titanate according to the present invention, and is within the temperature range ζ
It has an exothermic peak due to this crystallization.

The endothermic peak at 665°C in song iA is thought to be due to the decomposition of nitrate radicals and ammonium impurities.
It is recognized that the amount decreased due to washing with water.

Oxalate pickling (co-precipitation) As mentioned above, decomposition of complex oxalates occurs only at high temperatures of 700°C or higher; on the other hand, peroxide pickling (co-precipitation) As is clear from the TA curve of curve B in Figure 3,
Lead titanate crystallizes for the first time at a temperature above 600°C.

Comparing these facts, it can be seen that the lead titanate according to the present invention has a remarkable feature of having a lower crystallization temperature than lead titanate produced by the conventional solution method.

In addition to these advantages, the lead titanate according to the invention has the advantage that, upon heat treatment at a constant temperature and for a certain time, the crystallinity of the formed crystals is significantly high.

That is, FIG. 4 shows that the molar ratio of P b O' T 102 is 1.
Figure 5 is an X-ray diffraction diagram of amorphous lead titanate obtained by heat treatment at 550°C for 10 minutes. is an X-ray diffraction pattern of amorphous titanic acid with a PbO:T+02 molar ratio of 1:1 heat-treated at 850°C for 5 hours, where curve A is the one according to the present invention and curve B is the one according to the present invention. Oxide method

Comparing the heights of the diffraction peaks in these figures, it becomes clear that crystallization occurs to a higher degree in the case of the present invention.

Further, the amorphous titanic acid fine particles according to the present invention were prepared by adding water to the aqueous slurry under reduced pressure (500 mmH, absolutely) to form a wet cake, drying this cake, and baking it at 600°C to form a molded body. However, the pore volume is significantly smaller, i.e., less than 0.20 m1/j; l, as measured by mercury intrusion method in a pore radius range of 430 to 147 x 104.
Indicates a pore volume of iC0,10m179 or less.

Conventional solution method 1. ! ;! As is clear from the pore distribution curve in Figure 6, lead titanate obtained by oxalic pickling or peroxide method was measured under the conditions described above, and in both cases the lead titanate was 0.35r.
Shows the pore volume under nl/9pJ (curve A...
・Oxide method, curve B...peroxide method).

In contrast, the lead titanate according to the invention curves C, l)
.

E (sample of the example described later/161-3...C,
1-10...I), 1-7...E) shows a significantly small pore volume,
At the same time, the volume of macropores in humans with a pore radius of 430 to 147×104 is suppressed to an extremely small level of less than 0.20 m1/!i7.

The fact that the molded product of the amorphous lead titanate of the present invention exhibits such an extremely small pore volume is that the particle size of the amorphous lead titanate is uniform, and the grain size is uniform, as compared to the old model, in which the particle size of the amorphous lead titanate is fine. The fact that the filling state is close to closest packing is evident when G.

Since the amorphous lead titanate according to the present invention has the novel properties described above, it can be used as a ceramic base material (providing excellent functions and effects).

Conventionally, when producing a sintered body such as a ceramic using a powder such as lead titanate as a raw material, the characteristics such as the particle size and crystallization characteristics of the raw powder are determined by the various physical properties of the sintered structure and the manufacturing process. It is known that this has a significant effect on workability.

That is, the sintered body is made by using the powder raw materials mentioned above as they are, or after adding various compounding agents or additives, molding them into the desired shape at 770 pressures, and then pressing the molded bodies at normal pressure or It is produced by heating under pressure to a temperature below the melting point.

In this sintering process Q, bonds are formed between the particles due to force and heat, and at the same time (pores or grain boundaries interposed between the particles are diffused and left out of the system, forming a compact compact). This results in an increase in oxidation and mechanical strength.

As mentioned above, the lead titanate according to the present invention is amorphous but also has an extremely fine apparent particle size, so the surface energy that is a driving force for sintering is large, and this makes it possible to increase the sintering speed. Becomes a master.

Furthermore, since the grain size is 1, there are many grain boundaries, which promotes the diffusion of pores and has the advantage of increasing the densification rate.

Furthermore, it is known that a ceramic body generally exhibits better physical properties as its constituent crystal grains become smaller, that is, as it has a more dense and detailed structure.

As mentioned above, the amorphous lead titanate according to the present invention has a fine particle size, a low crystallization temperature, and a high crystallization rate, so it can be sintered at a lower temperature and in a shorter time, which results in crystallization. It is possible to suppress the growth of grains into coarse grains and produce a sintered body having a fine and uniform microstructure.

In particular, in the production of ceramic bodies using lead titanate as a chemical, lead oxide fume is generated during sintering,
It is often observed that the composition of the ceramic body differs from the blended composition, but when the lead titanate of the present invention is used as a base material, crystallization and firing can be performed at low temperatures in a short time, and the composition can be changed. As a result of the homogeneity of lead oxide, the formation of lead oxide fume can be suppressed and the composition can be precisely controlled.

In addition, the amorphous lead titanate particles used in the present invention have a significantly small pore volume when formed into a molded body, so that a ceramic body with an extremely dense microstructure can be obtained, and when sintered, the pore volume is extremely small. The advantage is that the shrinkage rate can be made significantly smaller than when conventional amorphous lead titanate is used.

In the lead titanate of the present invention, it is desirable that PbO and Ti02 exist in equimolar amounts, but depending on the various usages described below, the molar ratio of PbO:Ti02 can be adjusted to 6:
It may vary within the range from 1 to 1:1.1, in particular from 4:1 to 1:l.

In this case, when the content of the lead oxide component is high, the X-ray diffraction image of this product is similar to that of the wet method - lead oxide (although it may show a peak peculiar to this, the lead titanate itself formed is amorphous). It should be noted that.

The amorphous lead titanate of the present invention has a voltage of 8.3 to 9.2 VCC.
true density of 0.2: primary particle size less than Kron, wave number 140
0 to 1410 cm-”Ic infrared absorption peak, and 9
It is produced by reacting lead monoxide having a chromic anhydride reaction rate of 4% or more with titanium oxynitrate or its hydrolyzate in an aqueous medium at the above-mentioned molar ratio.

The above-mentioned lead monoxide raw material is prepared by filling a rotating mill with granular metal lead, a liquid medium, and oxygen gas; at least a part of the granular metal lead moistened with the liquid medium is lower than the surface of the liquid medium. The rotary mill is rotated under conditions in which the particles of lead metal are exposed to the upper gas phase and rub against each other in the liquid medium, whereby ultrafine particles of lead monoxide are dispersed in the liquid medium. by separating said dispersion from granules of metallic lead and recovering the lead monoxide formed from said dispersion in the form of a fine powder, the details of which are described in this text. U.S. Patent No. 41171 proposed by the inventors
It is described in the specification of No. 04.

This wet method - lead oxide has a fine particle size and is highly dispersible in water (
The aqueous slurry is extremely compatible with water, to the extent that it is difficult to separate the water and particles by conventional means.

In addition, this wet method - lead oxide has extremely superior reactivity compared to conventional lead monoxide (lead oxide), and has the property of reacting with various acids without using a catalyst. .

This wet method - there are three types of lead oxide, namely (A)
The following X-ray diffraction image plane distance d(A) Relative intensity (I/l0) 5.03
7.2 3.11 100 2.81 38.6 2.51 20.5 1.98 29.8 1.67 25.5 1.55 10.0 1.54 14.2 X- which is substantially the same as It has a line diffraction image, 8.80 to 9.
Lead monoxide having a true density of 17 g/cc, a primary particle size of 0.01 to 0.05 microns, and an orange to lemon hue.

(B) The following X-ray diffraction image plane distance d(λ) Relative intensity (I/l0) 3.07
30.5 2.95 100 2.74 7.42, 38
5.2, has a true density of 8.35 to 9.297 cc, a primary particle size of 0.01 to 0.05 μ, and a white to yellow hue. lead monoxide with.

(C) The following X-ray diffraction image plane distance d (A) Relative intensity (i/1o) 3.62
100 3.38 34.6 3.14 11.6 Plane spacing d (Relational strength (I/l0) 3.05
74.3 2.95 11.6 2.91 17.1 2.86 75.6 2.55 34.9 2.46 21.1 2.33 20.4 Has, 8.80 to 9,
There is lead monoxide which has a true density of 197cc, a primary particle size of 0.01 to 0.05μ, an irrigation water content of 0.2 to 0.8 mol per 1 mol of Pb0, and a white hue. , any of which can be used for the purposes of the present invention.

In the present invention, the titanium oxynitrate or hydrolyzate used together with the other raw material is expressed by the following formula % formula % (1) where m is a number from 0 to 1, particularly from 0.1 to 0.5. Those having the following chemical composition are preferably used.

Although titanium oxynitrate is water-soluble or acid-soluble, partial or complete hydrolysis products of titanium oxynitrate can also be used as long as they can be atomized or colloidally dispersed in an aqueous medium. It can be used for the purpose of invention.

Such a hydrolysis product can be obtained, for example, in the form of titanic acid, by heating and hydrolyzing an aqueous solution of titanium oxynitrate or by neutralizing the nitrate radical with an alkaline agent.

Amorphous lead titanate is easily produced by mixing and reacting both raw materials in an aqueous medium.

In this case, it is preferable to carry out the reaction by adding the aqueous solution or aqueous dispersion of titanium oxynitrate or its hydrolysis product all at once to the aqueous slurry containing lead oxide in the wet method. An aqueous slurry of lead monoxide may be added to the raw material slurry, or both raw materials may be added to an aqueous medium at the same time to carry out the reaction.

During the reaction, there is no particular restriction on the raw material concentration in the aqueous medium, but in terms of operation, the solid content concentration should be between 50 and 450 (g/1
．． ) is suitable.

Room temperature is sufficient for the reaction temperature, but if desired, it may be heated to a temperature below the boiling point.

The reaction time may be any time as long as the two raw materials are mixed evenly and uniformly, and is generally in the range of 1 minute to 60 minutes.

The pH of the mixture during the reaction is 5.5 to 10. In particular, it is desirable to maintain the pH within the range of 6 to 9, and this pH adjustment can be easily carried out by adding an alkaline agent, especially aqueous ammonia, to the mixed system.

In the present invention, the above-mentioned wet method - an aqueous filter of lead oxide and an aqueous solution or dispersion of titanium oxynitrate or its hydrolyzate are reacted by rapid mixing under high-speed shear stirring. It is desirable to have them do this.

In other words, in this mixed reaction system (in this case, ammonium nitrate is mixed due to the nitrate radicals accompanying the ammonia and titanium components added for pH adjustment, and the particle size of lead titanate produced by the coexistence of this ammonium nitrate is It tends to get bigger.

For example, when carrying out a reaction by gradually separating the titanium component into an aqueous slurry of lead oxide in the wet process, ammonium nitrate acts as a crystallizing agent, and the unreacted wet process lead oxide particles grow. This is thought to be the cause.

This tendency can be effectively overcome by rapidly mixing both raw materials.

In the present invention, it is particularly important to use the above-mentioned wet method - a combination of lead oxide and titanium oxynitrate or a hydrolyzate thereof.

That is, when lead monoxide produced by a normal dry method is used as a raw material, the X-ray diffraction peak of lead monoxide remains as it is in the mixture, and the amorphous titanium targeted by the present invention is produced. Acid lead is impossible to obtain.

This tendency is similarly observed when ordinary dioxide or hydroxide is used as the titanium raw material.

In the method of the present invention, the fact that lead oxide and titanium components are reacting is confirmed by the fact that, as mentioned above, the X-ray diffraction peaks characteristic of these raw materials disappear and an amorphous product is produced. This can be easily confirmed by the fact that the reaction product precipitates and separates from its mother liquor, the aqueous medium.

Wet process - Lead oxide is extremely difficult to separate by sedimentation from an aqueous medium, but the product reacted with the titanium component exhibits the new property of being easily precipitated from an aqueous medium, and is also very difficult to separate from this amorphous medium. Lead titanate precipitates are obtained with significantly lower water holding capacity.

For example, the precipitate obtained by the above-mentioned peroxide method generally has a water content of 65% by weight or more, which is sufficient for the measurement method described below, whereas the precipitate according to the present invention has a water content of 2.
The water content is only 30 to 40% by weight when the weight is 5 to 45% by weight.

The amorphous lead titanate according to the present invention can be used as various ceramic bases in the form of aqueous slurry, wet cake, or dry powder, or if necessary, after crystallization by firing, it can be used as various ceramic bases. be able to.

Of course, this amorphous lead titanate may contain additives for ceramics known per se, such as Zr02-NrO-M.
n02- WO3゜B12o3. La2O3s Nb
205, Ta205.5b203゜ThO□, ni2
0. Li2CO3, Al2O3, 5r203゜Cr2o
3s Fe203- Co01Mg01ZnOzCdO
.

A ceramic composition can be made by combining one or more of PbZrO3, PbCoTa03, and other rare element oxides.

The production of ceramics can be carried out under conditions known per se, except for the use of the above-mentioned base material, but the various advantages mentioned above, both in terms of production operations (1) and in terms of the properties of the ceramic body, benefits achieved.

The invention is illustrated and illustrated by the following example.

Reference Example 1 Lead oxide prepared by a wet method (Hereinafter, in this example, lead oxide prepared by a wet method may be abbreviated as w-pbo.

) was produced in accordance with the method described in US Pat. No. 4,117,104.

That is, production of lead monoxide having a density of 8.3 to 9.2 g/cc, a number average particle size 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 coefficient or higher. Outline the law.

200 kg of granular metal lead (electrolytic lead purity 99.99%) with a diameter of 2 to 7 mm was placed in a rotary stainless steel tube mill (inner diameter 34.5 CrIL, length 130 crf L, internal volume approximately 120 mm), and water was poured into it. 301 and oxygen (2k
By filling the tube mill with water (g gauge pressure) and rotating this tube mill, a part of the metal lead moistened with water is held down by centrifugal force into the oxygen gas phase above the water surface, and the surrounding metal lead particles are The ultra-thin film layer of water absorbs oxygen, where lead oxide is produced, and the ultra-fine particles of lead monoxide produced by the metallic lead particles rubbing against each other in the water are dispersed in the water. Concentration Pb
O33.5g7100ml! dispersion (sample number w-p
b.

-1) was obtained.

The wet lead oxide slurry obtained here was dried, dried at about 80° C., and then pulverized to produce a wet lead oxide dry powder product (sample number W-PbO-2).

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

In addition, each measurement method followed the method below.

a) Pour the benzene solution into a true density pigsmeter, fill it up, and measure the weight W.
And measure the temperature (Ti) with the provided thermometer.

Next, the benzene is discharged, and the sample is collected in a predetermined amount (M (g)
), further benzene was added, the mixture was placed in a vacuum desiccator, the pressure was reduced to 3 mm H9 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 and take out the pycnometer, fill it with benzene, measure the weight (W') and temperature (Ti), and calculate the following equation (2).

dS: sample density d: Specific gravity of benzene in Ti’C (b) Number average particle size.

Using a superscope type (JEM-50) electron microscope manufactured by JEOL Ltd., samples were taken using the water paste method using a collodion-carbon vapor deposited film.
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 in accordance with the method described in JIS K-1456 (Lissage method of determination), and the content was expressed in (%).

(d) Pour 500rfLl of water into a beaker with a chromic acid reaction rate of 21, and remove the sample lead oxide powder of 69. Weigh the ol accurately and slowly add it while stirring well to fully disperse it in the water.
This dispersion is then heated to 65°C.

On the other hand, prepare an aqueous solution of chromic anhydride (30.94 g
7100 ml of water) and 100 ml of water were slowly separated for 30 minutes while stirring, and further aged at 65° C. (maintained at 65° C., stirred and aged for 60 minutes to form lead chromate crystals.

Next, the lead chromate crystals are filtered through a 3-sided paper, washed with water, and the lead chromate produced here is dried at 110°C to determine the amount of chromic acid fixed as lead chromate. Quantitative analysis was performed using the amount of chromic anhydride (Cr03) (&), and from this result, the amount of fixed chromic acid (CrO2) (,9)
From the ratio of (AC) and the amount (g) (TC) of chromic acid (Cr03) of the raw material used, RC=AT/TCX100 (%) from the following formula (3)...
3) The chromic acid reaction rate (RC%) was determined.

(e) Infrared absorption spectrum measurement Under reduced pressure vacuum (3 mm H, 9) 400 k using an infrared absorption spectrum measuring device manufactured by JASCO Corporation (model IR-G)
Molded in a KBr tablet molding machine under g/cit pressure,
Absorption spectrum 1 in the wavelength range of 4,000-400 cm-'
I made Hell self-recording diffraction.

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

■S: Strongest S: Strong M: Normal W: Weak b: Minute sh: Extremely small (f) X-ray diffraction measurement is wide angle Ca
The sample was measured by the powder measurement method using a tA2227, Proportional Counter) according to the following diffraction conditions.

Diffraction condition target Cu Filter Ni Voltage 30KV Current 15mA Count range 500cps High voltage
1450V time constant 1 sec chart
Speed ICrrVrnin Scanning speed 1°/rn l n Diffraction angle (2θ)
17°～60.5°Slit width 1°-1°-0,3(g)
Compositional analysis of lead oxide The compositional analysis was conducted in accordance with the method described in TI8 K 1456 (Litharge's 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 oxide (pbo) Weigh the sample accurately, measure the moisture content, and after converting the moisture content, (
If the sample was a powder, it was moistened with water beforehand.

) Add 6N acetic acid, heat, dissolve, and then cool.
Adjust the pH of the sample solution to 5.0 with aqueous ammonia and buffer.
0 to 5.5 (after this preparation, 1720 molar concentration of EDTA (
The content (%) of -lead oxide (pbo) was determined on a dry basis by titration with a disodium ethylenediaminetetraacetate solution.

(g-2) Komyotan (pb3o4) 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 lium acetate, and then a certain amount of A 1/10N sodium thiosulfate solution was added, and after a certain period of time, back titration was performed with a 1/10N iodine solution using the starch solution as an indicator. Determined based on standards.

(g-3) Metallic lead (pb) After sampling in the same manner as in the case of -lead oxide in (g-1,) above, 6N acetic acid was added and dissolved by heating. Add a small amount of hydroxylamine hydrochloride to dissolve the lead peroxide compound present in the sample,
Next) Wash each door with P paper, wash with warm water, and wash until no lead components are detected in the washing solution. Transfer the 05 paper with the residue on the door paper to an Erlenmeyer flask (sieve) to remove the metal lead on the door paper.
Dissolve with 2 to 3 drops of 30% hydrogen peroxide solution and nitric acid.
Next, the pH was adjusted to about 51 using a buffer solution of aqueous ammonia and 1 helium acetate, and then ED with a concentration of 17,100 molar was adjusted.
The content (%) of metallic lead (PB) was determined on a dry matter basis by titration with a TA solution using xylenol orange as an indicator.

(g-4) Impurities (Fe, Cu) In the case of -lead oxide in (g-1) above, after sampling in the same manner as above, nitric acid and hydrogen peroxide were added to dissolve, and evaporation to dryness was repeated. JIS K 012 sample preparation solution
Fe (iron) and Cu (copper) were quantified in accordance with the ``Atomic Absorption Spectrometry General Rules'' and their contents were calculated 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 described.

As the zinc oxide powder used as a raw material, we selected sunny green zinc oxide powder manufactured by the Shimadzu lead powder method.

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 having 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.
/100Tll concentration.

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

The hydrocyclone used in this 5 has a diameter of 55 m1φ, a conical apex angle of 20°, an inlet of 8 Vrmφ, a downstream nozzle of 6 mmφ,
A stainless steel liquid cyclone with a discharge pressure of 1.8 kg/crIt was used.

The composition of the aqueous slurry of homogeneous lead zinc oxide, which has been classified and separated using this liquid cyclone, has a solid concentration of 12.4 i/100 rIll, and the metallic lead component in this solid content. The amount was 10.5% by 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 aqueous slurry after the oxidation process, and the lead monoxide slurry is wet-oxidized using lead zinc oxide as a raw material. W-PbO-3) was recovered.

The aqueous slurry recovered here has a PbO concentration of 18.
It was 47i/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, an ingot of electrolytic lead with a diameter of 2.5mm is made using a lead-acid machine.
After molding it into a cylindrical shape of 5 cm x length 2.0 CrIL, it was molded into a cylindrical shape with a length of 5 cm and a length of 2.0 CrIL.
00) Powders 489 to 516 (1925), while grinding metallic lead using the dry grinding method in a rotary mill in accordance with the Shimazu lead powder method described in 1925, clear green lead zinc oxide powder (talking lead) was produced. powder) was produced.

Next, the recovered zinc oxide powder is placed in a rotary furnace, oxygen is added, and the mixture is combusted with stirring.The zinc oxide powder is oxidized at a temperature of approximately 630 to 720 degrees Celsius, and the heat of combustion of the zinc oxide (temperature rise caused by this is measured). As soon as there is no longer any combustion (temperature rise), it is rapidly discharged into a cooling chamber and cooled, yielding yellow granular lead oxide.

Next, the yellow granular lead oxide is crushed.1. A yellow lead monoxide powder (raw material number D-PbO) with an orange color was prepared by classification using a gas cyclone method.

Reference Example 4 A method for preparing titanium oxynitrate or its hydrolyzate will be explained.

The basic preparation method is the method described in JP-A-54-54914 and JP-A-54-80297. .

Preparation process A: Combination of raw materials and alkali, B
: Reaction with alkali, C: Removal of alkali IJE'J soluble components, J]: Leaching of titanium with nitric acid, E: Hydrolysis and partial neutralization of nitrate radicals as necessary. The adjustment process was performed.

Four types of raw materials containing titanium metal components were selected: iron sand slazo, ilmenite ore, high titanium slag, and titanium oxide.

As the iron sand sludzo, Nippon Koshuha Co., Ltd. (Japan Koshuha Co., Ltd.) selected a water-slag iron sludzo with the composition shown in Table 2 below, which is produced as a by-product during iron sand smelting. Wet grinding was performed using a rotary mill using balls as the grinding medium to produce 320 mesh (Tyl
er) Iron sand slazo powder prepared by passing through the powder, making it into a fine powder, dehydrating and drying was used.

As the ilmenite ore, ilmenite ore from the Soviet Union with the composition shown in Table 2 below was selected, and as in the case of iron sand slazo, wet pulverization (trowel, pulverization to 320 mesh throughput, dehydration, drying, and preparation of ilmenite) A crushed product was used.

As a high titanium slug, Canada's QuebecIr
on and Titanium Co, the following No. 2 product manufactured by deironizing ilmenite ore as a raw material.
Select a high titanium slag having the composition shown in Table
A total of 320 mesh was wet-pulverized (pulverized, dehydrated,
High titanium slag powder prepared by drying was used.

As the titanium oxide, anacuse-type titanium oxide (TiO2) powder shown in Table 2 below, manufactured by Tohoku Kagaku Kogyo ■, was used.

As the flux, caustic soda (NaOH), which is commercially available as an industrial raw material, was selected, and a caustic soda solution having a concentration of 50% by weight was prepared to facilitate homogeneous mixing on the titanium raw material powder.

That is, commercially available solid caustic soda as it is cannot be homogeneously mixed with raw material powder, and industrial mixing could not be performed, so caustic soda was first made into a liquid state.

The mixing ratio of each raw material powder and the fluxing agent caustic soda (NaOH) is the chemical reaction equivalent of the acidic component that reacts with the alkali contained in the raw material. Amounts corresponding to 1.5 times the chemical reaction equivalent were selected and blended with a caustic soda solution (50 wt%).

At this time, the amount of NaOH was limited to 1.5 times the chemical reaction equivalent, so the mixing ratio of the raw material and water (H2O) differs depending on the raw material, and the amount ratio is 10 times the dry weight of the raw material.
Table 3 shows each part by weight relative to 0 part by weight.

For blending and forming granules, a bag mill with an internal volume of 60 mm was used, a predetermined amount of caustic soda solution as a flux was added to about 10 mm of the raw material, the process was carried out for about 30 minutes, and then this mixture was milled into 5 mm diameter bags. Pelletize into a columnar shape using a vertical granulator equipped with a perforated plate with holes, and heat to 100 to 110°C.
The mixture was dried to prepare granules containing raw materials and a flux.

In addition, when titanium oxide is used as a raw material, it is mixed in the bag mill mentioned above, and the mixture is dispensed in the form of a paste.
A paste-like mixture was prepared.

Next, as a granular melting reaction method, a rotary kiln type heating furnace was used.

The rotary kiln type heating furnace is made of iron with a diameter of 5 mm.
The inside of a kiln measuring 00m1 x 2000m in length was lined with castable caster 160) made of fireproof cement (Nichibei Tozai Seizo Co., Ltd.) whose main component was alumina, and the inner diameter was 300mmφ.

This circular kiln was placed on a rotary table, and a motor was driven so that it could rotate for 60 rotations.A rod-shaped silicon carbide heating element (2200 t long, Tecorundum manufactured by Toshiba Ceramic ■) was placed in the center of the kiln. The books were set so that the temperature inside the rotary kiln could be raised to about 1200°C.

In addition, the mixed granules are made to have a slight slope so that the mixed granules are continuously introduced into the heating rotary kiln from one inlet of the heating rotary kiln and continuously discharged from the other outlet. is maintained at a predetermined temperature for about IO minutes while rolling and moving in the rotary kiln, a melting reaction occurs, and the granular reaction product after the reaction can be easily and continuously taken out of the reaction system, that is, outside the rotary kiln. I made it.

The granular melting reaction is carried out by using the heating rotary kiln described above, maintaining the internal temperature of the kiln at the predetermined temperature shown in Table 3, and continuously introducing the mixed granular material into the kiln. The granular melting reaction was carried out by rolling and rotating the granules while moving from the inlet to the outlet for about 10 minutes while accumulating, and 14 types of granular reaction products were recovered.

The graininess of the reaction product recovered here is shown in Table 3, which shows the shape of the melted reaction.

In addition, in the case of a paste-like mixture made from titanium oxide, the paste-like mixture was heat-treated for 5 hours in an electric furnace maintained at 200 ± 10°C (melting reaction with a trowel to form dry granules). The product was obtained.

The granular or granular reaction products recovered in step 5 were green in the case of iron sand sludzo, greenish-brown in the case of ilmenite and high titanium slag, and grayish-brown white in the case of titanium oxide.

In addition, the shape of the collected particulate matter is represented by the following four levels of symbols, and the results are shown in Table 3.

The resulting reaction product was subjected to the following aqueous leaching step to remove colored harmful metal components contained in each raw material as well as alkaline components.

Equipment for the aqueous leaching process of alkali-soluble components includes:
Stainless steel leaching tank equipped with a stirrer (inner diameter 600m1)
A steam pipe was installed at a height of 700 mm to heat and keep the inside of the leaching tank warm.

This leaching tank (filled with 807 g of distilled water and connected to a steam pipe for about 80 g.
After heating to 0°C and maintaining the temperature at 60±10°C during the leaching process (using a stirrer to thoroughly mix and stir the inside of the leaching tank, 25 kg of each reaction product was 1
Coarse pulverization using water is carried out using water so as to pass through a 2-mesh sieve, and this slurry is added to leaching alkali-soluble components such as colored toxic metal components into warm water for about 30 minutes. Each leached slurry was recovered.

Each leaching slurry collected in this process is separated into solid and liquid by a filter press method, separated into tear fluid and water-containing cake, and then heated water (approximately 80° C.), and the collected mother liquor of the tear fluid and washing solution were collected, and the water-containing cake containing titanium as the main component was collected.

Next, the water-containing cake containing the recovered titanium component as the main component is subjected to a leaching step with nitric acid to make it soluble in nitric acid.

As the apparatus for the nitric acid leaching process, a stainless steel leaching tank equipped with the same stirrer as used in the aqueous leaching process described above was used.

This stainless steel leaching tank is filled with about 251 nitric acid solution having a concentration of 50% HNO3, and about 13 kg of the dried leaching residue is gradually added thereto while stirring.

After adding the leaching residue, leaching with nitric acid is carried out for 1 to 2 hours while stirring slowly. If the raw material contains silica components, the silica components are silica hydrogels with good sedimentation properties, titanium, calcium, magnesium, and aluminum. and iron components form a clear nitrate solution.

When this was filtered and separated using a filter, a nitric acid solution containing a titanium component as a main component and having the composition shown in Table 4 below (each metal component contained is expressed on an oxide basis) was recovered.

Next, the recovered titanium nitric acid solution was hydrolyzed by heating or with an alkali, and if necessary, a part of the nitrate radicals were neutralized with an alkali to recover a homogeneously dispersed sol of titanium hydrate.

The thermal hydrolysis method involves heating a nitric acid solution of titanium at a temperature of 70°C or higher under normal pressure or 60°C or higher under 1 to 3 atmospheres with stirring to hydrolyze titanium hydrate. After settling the material, filtering and separating the mother liquor, and separating most of the nitric acid, add a slightly alkaline solution (for example, dilute aqueous ammonia) to a hydrolyzate of the titanium hydrate so that the pH is 5 or more. was decomposed and passed through a 325 mesh sheath to prepare a homogeneously dispersed sol of titanium hydrate.

In addition, as an alkali hydrolysis method, a 10% ammonia aqueous solution is added to a titanium nitric acid solution at room temperature (3
0°C or below) to form a gel-like precipitate of titanium hydrate, followed by the filtration separation method (
After separating most of the nitric acid and ammonia components, the gel-like precipitate recovered here is redispersed in water under high-speed stirring (for example, using a household mixer) and passed through a 325 mesh sheath to a pH of at least 2.0. The above homogeneous dispersion sol of titanium hydrate was recovered.

Example 1 A ceramic base made of substantially amorphous lead titanate obtained from a homogeneously dispersed sol of lead oxide particles and titanium hydrate by wet method will be described.

The lead oxide particle slurry prepared by the wet method was prepared by the above-mentioned Reference Examples 1 and 2 (lead oxide prepared by the method described here (raw material number W).
-PbO-1, W-PbO-2, and W-PbO-3
) was selected.

As the homogeneous dispersion sol of titanium hydrate, the titanium sol prepared by the method described in Reference Example 4 (raw material numbers S TlO21, S T102-2, S T
lO23, S TlO24 and 5-TlO25) were selected.

The manufacturing conditions can be arbitrarily selected within the range shown in Table 4.

Specific combinations of these manufacturing conditions are shown in Table 5 (each amorphous lead titanate was manufactured according to the conditions shown).

As a comparative example, powder litharge (>pbo) prepared by the method described in Reference Example 3 using the so-called dry method was selected as the lead oxide raw material, and when lead nitrate was used as the lead oxide raw material, the reagent nitric acid Lead (P b (NO3)2) was chosen.

Commercially available rutile-type titanium oxide (
RT i02 ) powder and reagent titanium oxynitrate (
TiO(NO3)2) was selected.

A specific manufacturing method involves pouring a predetermined amount of lead oxide aqueous slurry at a predetermined concentration into a stainless steel container (inner volume 1.
A predetermined concentration of a titanium component sol dispersion was collected in a lead component slurry solution kept at room temperature (20±5°C) and stirred at a high speed of 1.00 rpm. , all at once (Koebetsu, then continue 10
Continuously stirring for 1 minute to carry out reaction ripening, resulting in substantially amorphous lead titanate reaction product slurry 1 with good sedimentation properties.
Three types were manufactured.

The lead titanate of the comparative examples was manufactured according to the following methods.

H-1 = JP-A-54-106514 and 1982-1
According to the method described in the specification of Publication No. 06515, both raw materials were wet mixed and a mixed slurry was recovered.

H-2=The method described in Example 1 of the specification of Japanese Patent Publication No. 54-18675 (according to this method, using lead nitrate and titanium nitrate as raw materials, hydrogen peroxide and aqueous ammonia in an amount equivalent to 10 times the molar amount) was added and stirred to form a precipitate of composite peroxide.

The following physical property values were measured for the reaction product slurry of the composite oxide produced by each of the above methods.

■Water content, ■Uniformity of composition by chemical analysis, ■Shape and particle size measured under optical and electron microscopes, ■Crystal form by X-ray diffraction, ■Reaction analysis by pTA, ■Mercury intrusion porosimeter and BET method. Seven items such as measured density and lead fume generation amount were measured using the measurement method shown below, and the results are shown in Table 5 and attached figures L3 and 4.
, 5°6 and Photo 2.

■ Water content (X): The water content (X) in the PbO-nTiO2 x H2O formula is the reduced pressure P at a reduced pressure of 500 mmH, 9.
, Pb from a constant weight using iM cake as a sample.

It was defined as the weight (%) obtained by dividing the value obtained by subtracting 2 weights of T io and T io by the sample weight.

■ Uniformity of composition Pour 100ml of each reaction product slurry into a 10011L measuring cylinder, let it stand for 10 minutes, and then pour 10m of each slurry from the top (U), middle (m), and bottom (1) of the sedimentation layer.
Collect each sample with a pipette and filter to obtain a sample of water-containing cake. Accurately weigh approximately 2 g of this wet sample, dissolve the Ti content with nitric acid and sulfuric acid, and analyze the Ti content using the conventional metal AI reduction method. Then, the Pb portion was separated as a pbso4 precipitate, and then dissolved in CH3COONH4, and then dissolved in EDTA using the usual method.
Analyze the PB content using the method, calculate the molar ratio of both, and calculate the average deviation rate (%) of the molar ratio of each sample using the following 4 formulas.
) was determined, and the uniformity of the composition was evaluated using this value.

mo; Pb0aTiO2 molar ratio m Confirm that there are no soluble components by chemical analysis, wash thoroughly as necessary, and then bake each pale yellow cake at 200 to 1000°C, leaving any lumps in the water-containing cake C. For those that have been dissolved with a small amount of water, applied to a glass plate, and heat-treated, they are crushed lightly in a vase, rinsed with a small amount of water, and then applied to a glass plate, and the shape and shape of each can be observed directly under an optical microscope with a magnification of 40x15x. Measure the multiplied grain size (indicated by the maximum grain size) 1, f, =.

In particular, regarding the shape, we confirmed the presence or absence of a continuous phase characteristic of gel-like amorphous materials.

A portion of the sample was also measured using a scanning electron microscope.

(2) Crystal form test The samples applied in (2) were simultaneously subjected to X-ray diffraction using a powder method, and the crystal forms of the wet sample and its heat-treated product, as well as the crystallinity of P bTr 03, were compared and examined.

■ Reaction analysis by DTA After each sample was heated to a predetermined temperature at a rate of 10°C/min using Rigaku Denki's vehicle-mounted DTA800 device, a DTA curve was drawn, and then the raw material sample was again added to the peak of the curve. The samples were rapidly cooled without heating in the same apparatus, and then the heat-treated samples obtained were taken out and subjected to X-ray diffraction to examine the state of the crystallization reaction.

■ Moldability and compactness test The sample applied to ■, that is, the vacuum cake at a vacuum degree of 500 mmH, p, was baked at 600°C and the shape obtained was subjected to mercury intrusion method Mo1) EL 5-7 ], ] The pore volume, pore distribution, and specific surface area were measured using a Type 8 porosimeter and the BET method, and the moldability of the shaped article and the density during heat treatment were evaluated from the values.

■ Amount of lead fume generated After calcining each powder sample at 800°C for 1 hour, accurately weigh the sample (its weight is W, L, then calculate the lead fume generation from the weight (W2) after calcining at 1000°C for 1 hour. Amount Lv (weight%)
was defined by the following formula.

From the above results, as is clear from Table 5, by reacting both bO of the present invention (the W-T used) and S TlO2 using a high-speed stirring mixing method, the lead content of the reaction slurry obtained is as follows. In the composition of titanium and titanium components, in particular, the heterogeneity of the composition that tends to occur in the conventional oxide wet mixing method (sample number H-1) is hardly observed, and in addition, comparative example 2 (sample number H-1) H
-2), it was found that the homogeneity was excellent.

From this result, it is understood that lead titanate is more likely to form a highly homogeneous chemical composition than lead titanate produced by any conventional method.

Furthermore, as is clear from the apparent particle size of the series of photos taken with an optical microscope in Figure 2 and the X-ray diffraction diagram in Figure 5, it is clear that the water content at the time of formation is at a high temperature of 1000°C (this is due to its thermal history). (
Therefore, as seen in the photograph of Comparative Example 2 (H-2) in FIG. As is clear from the X-ray diffraction diagram in FIG. This is the surprising shape characteristic of lead titanate, and this point is understandable because the water content is extremely small compared to Example 2 (2).

Furthermore, as is clear from the TA curve in Figure 3 and the X-ray diffraction diagrams in Figures 4 and 5, lead titanate (PbTi)
The crystallization temperature as 03) is 500℃, which is a low temperature not found in conventional methods, and the crystallinity of P b T + 03 when fired at 850℃ is much better than that of conventional methods. It is also understood that

Furthermore, as is clear from Table 5 and FIG.
The pore volume, pore distribution, and specific surface area measured using the method The molding of lead titanate obtained by the method of the present invention is smaller in surface area value, especially in pore volume (in this case it can be said to be extremely small, but in more detail) in terms of macropore volume with a pore diameter of 40 mm or more. It is well understood that the lead titanate according to the present invention has extremely excellent compactness during molding and sintering.

Furthermore, from the characteristics of the fine-grain amorphous lead titanate of the present invention described above, it is well understood that the amount of lead fume generated in Table 5 is smaller than that of the conventional method.

[Brief explanation of the drawing]

FIG. 1 is an X-ray diffraction diagram of the lead titanate ceramic base of Sample 1-7 according to the present invention, and FIG. 2-A-1 is an X-ray diffraction diagram of the lead titanate ceramic base sample No. ), FIG. 2-A-2 is an optical micrograph of the lead titanate of FIG. 2-A-1 fired at 900°C, and FIG. This is an optical micrograph of hydrated lead titanate (sample number H-2) obtained by the oxide method, and No. 2-B
Figure 2 is an optical micrograph of the titanium lead fired product at 900°C in Figure 2-B-1, and Figure 3 is an optical micrograph of the amorphous lead titanate (curve A) and the peroxide method (curve A) according to the present invention. This is a suggested thermal analysis curve of the amorphous lead titanate (curve B), and FIG. Fig. 5 is an X-ray diffraction diagram of the product fired at 850'C (curve A) of lead titanate according to the present invention (curve B) and the titanium produced by the peroxide method. FIG. 6 is an X-ray diffraction diagram of the acid calcined product at 850° C. (curve B), and FIG.
', lead titanate of sample H-2 by peroxide method (curve B
), the pore distribution curves of lead titanate samples 1-3, ■-10 and 1-7 according to the present invention (curves C, D and E, respectively) are shown, respectively.

Claims (1)

[Claims] I The molar ratio of PbO:TiO□ is 6=1 to 1:1.
1, the lead titanate has an apparent particle size of 5 μm or less and a particle size of 500 to 60 μm.
Consisting of fine particles with a crystallization temperature of 0°C, the fine particles are dehydrated under reduced pressure from an aqueous slurry and then heated to 600°C.
0.2ml, measured as a molded body obtained by firing with
/9 or less mercury intrusion method pore volume (pore radius 430-14
7X10'λ). 2. The ceramic base according to claim 1, wherein the molar ratio of PbO:TiO2 is in the range of 4=1 to 1:1. 3. The ceramic base according to claim 1, which has a mercury porosimetry pore volume of 0.1 m17 g or less. 4. The ceramic base according to claim 1, wherein the amorphous lead titanate is a hydrated material having a water content of 25 to 45% by weight. True density from 58.3 to 9.2 g/CC, primary particle size less than 0.2 microns, wave number 1400 to 1410 crn
Lead monoxide having an infrared absorption peak at -' and a chromic acid anhydride reaction rate of 94% or more, and titanium oxynitrate or its hydrolyzate at a PbO:TiO2 molar ratio of 6:1 to 1: 1. A method for producing a ceramic base comprising amorphous lead titanate, which comprises reacting in an aqueous medium at a ratio within the range of 1.1. 6 Titanium oxynitrate or hydrolyzate has a chemical composition of the following formula %, where m is a number from O to 1, and is dispersible in an aqueous medium. The method described in Section 5. 7 The aqueous slurry of lead monoxide and the aqueous solution or dispersion of titanium oxynitrate or its hydrolyzate,
The method according to claim 5, in which the reaction is carried out under high-speed shear stirring (by rapid mixing). 9. The method according to claim 5. 9. The method according to claim 5, wherein the reaction is carried out while maintaining the pH of the mixture in the range of 5.5 to 10.