JP2003137593A - Process for producing selenium-containing, colored soda- lime silica glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of time consumed for reaching stable production in the production of selenium-containing, colored soda-lime silica glass, due to the difficulty in adjusting the kiln-operating conditions for imparting a desired color tone and visible light transmittance to the glass. SOLUTION: In a method for producing the silica glass, a selenium compound, an oxidizing agent and a reducing agent are added to a raw material for soda- lime silica glass. The raw material is subsequently heat melted to prepare a glass melt. By adjusting the amounts of the oxidizing agent and the reducing agent added, the oxygen partial pressure of the glass melt at 1,400 deg.C is controlled in a range from 1×10<2> to 1×10<4> Pa. The yield of an elemental-state selenium, calculated by dividing the weight of the elemental-state selenium contained in the obtained silica glass by the total amount of selenium added, is controlled to >=5.0 wt.%. The absorbance ratio, calculated by dividing the absorbance of the silica glass at 500 nm by the absorbance at 430 nm, is controlled to >=1.0.

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION The present invention relates to a coloring component
Used for vehicle window glass and building window glass, etc.
Selenium-containing colored soda lime silica glass for use
The present invention relates to a manufacturing method for manufacturing. [0002] 2. Description of the Related Art Vehicle window glass or building window glass.
Soda Lime Silica Gas Containing Selenium Usable for Water
Lass is made from soda-lime-silica glass (soda lime
(Silicate glass)_Two, Al_TwoO
_Three, MgO, CaO, Na_TwoO as a coloring component
Zinc renate ZnSeO_ThreeAnd zinc selenide ZnSe,
In addition to selenium compounds such as selenium paste, iron oxide,
Add cobalt oxide, etc., heat and melt, and
It is manufactured after cooling and solidification. [0003] Colored soda-lime silica containing selenium
For example, Japanese Patent Application Laid-Open No. 9-278 describes a method of manufacturing a lath.
481 or JP-A-10-72236.
As disclosed, selenium and other color components
This has been done by adjusting the type or rate of minutes. one
And JP-B-59-4389 and JP-B-56-371.
As disclosed in Japanese Patent Publication No. 80, as a coloring component
Some studies have been made on the method of adding selenium. However, soda-lime silica glass
Focusing on the coloring principle and coloring action of selenium,
Controlling the oxygen partial pressure in the glass melt during the glass manufacturing process
To manufacture colored soda-lime-silica glass containing selenium
The law has not yet been considered. In selenium-containing colored soda-lime glass
The selenium produced is, depending on its valence, a cation (Se)⁶⁺Ma
Or Se⁴⁺), Elemental state (Se⁰) Or anion
(Se^2-), And the absorption of visible light
Because the situation is different, the presence ratio of selenium in each state may differ
Color of the obtained selenium-containing soda-lime-silica glass
Are different. Specifically, it is a cation
Se⁶⁺And Se⁴⁺Exists in soda-lime-silica glass
Also, there is no absorption of visible light and the glass becomes colorless,
Selenium Se⁰Is present in soda-lime-silica glass
Absorbs visible light having a wavelength of about 500 nm to form the glass
Has a warm color from pink to red and is an anion
Se^2-Is present in soda-lime-silica glass,
Coexist with Fe ions in lime-silica glass
By absorbing light near the wavelength of 430 nm,
It has a dull color. In addition, elemental selenium Se in molten glass
⁰Is a cation under the influence of oxygen in the glass melt
(Se⁶⁺)), Ie, SeO_Four ^2-, Yang y
ON (Se^{Four +}) As selenite, ie, SeO_Three ^2-When
Become. For vehicle window glass or building window glass, etc.
Color tone of useful selenium-containing colored soda-lime-silica glass
Is present due to the elemental selenium contained in the glass.
Warm tones of pink to red color or in glass
Coloration of other metal ions contained and elemental selenium Se⁰
Gray or bronze etc.
Various color tones can be obtained. [0008] SUMMARY OF THE INVENTION However, selenium
Production of colored soda-lime-silica glass
The valence of the ion depends on the type of coexisting ions, the melting temperature, and the melting atmosphere.
Glass production conditions such as ambient temperature and annealing temperature and annealing time
Elemental selenium Se ⁰To
Soda stone that is stable without being ionized during production
It is extremely difficult to exist in ash silica glass.
Was. Therefore, a colored soda-lime-silicone containing selenium is used.
In the manufacturing process of Kagurasu, colored soda stone containing selenium
Elemental selection of warm tones from pink to red on ash silica glass
N Se⁰Color tone and visible light transmission due to coloration
It was extremely difficult to obtain a stable rate continuously. [0010] Colored soda-lime silica glass containing selenium
Means float, rollout and duplex
Can be manufactured by a glass manufacturing method such as
Float method for window glass or building window glass
Selenium-containing colored soda stone
The raw material of ash silica glass is put into a melting furnace and heated and melted.
After being spread on molten tin as a glass melt,
Cooling the high-temperature strip glass coming out of the kiln
Normally, a small amount of color and visible light
It takes at least 10 hours,
To obtain a constant color tone and visible light transmittance continuously and stably
In adjusting the glass production conditions described above,
Operation of the production equipment must be complicated.
The problem that it takes a considerable amount of operation time and economical production is not possible
was there. Further, selenium has a high vapor pressure at high temperatures.
Selenium compound or paste-like selenium
Added as a coloring component of soda lime silica glass and melted
When added, most of the added selenium evaporates,
In selenium-containing colored soda-lime-silica glass
The amount of selenium to be added is 10 times the amount of selenium added before melting.
Selenium-containing colored soda lime gas
In the production of lath, if selenium use efficiency is very poor
There was a problem. [0012] SUMMARY OF THE INVENTION The present invention provides a selenium-containing dressing.
A method for producing colored soda-lime-silica glass, comprising:
The elemental selec
N Se⁰Containing selenium in high yield
Warm color from pink to red of colored soda lime silica glass
Color or color of other metal ions contained in the glass
And elemental selenium Se⁰Various color tones combining different colors
At the same time, the visible light transmittance is also stabilized, and the same color tone and
Colored soda-lime silica containing selenium with visible light transmittance
The purpose was to obtain continuous laths.
You. The present invention contains selenium as a coloring component.
Method for producing colored selenium-containing soda-lime-silica glass
As a coloring component for the raw material of soda-lime glass
At least a selenium compound is added, and an oxidizing agent and a reducing agent
After the addition, when heating and melting to make a glass melt,
By adjusting the addition amount of the oxidizing agent and the reducing agent, 140
The oxygen partial pressure of the glass melt at 0 ° C. is 1 × 10^TwoPa
Above 1 × 10^FourPa or less, and the glass melt is
Elements contained in soda-lime-silica glass obtained by cooling
Calculated by dividing the weight of elemental selenium by the total weight of selenium added
So that the yield of elemental selenium obtained is 5.0 wt% or more.
And 500 nm of the soda-lime-silica glass
Calculated by dividing the absorbance at 430nm by the absorbance at
Characterized in that the absorbance ratio obtained is 1.0 or more
Of producing selenium-containing colored soda-lime-silica glass
Is the law. In the present invention, elemental selenium Se⁰Income
The percentage is defined as the content of selenium-containing colored soda-lime-silica glass.
Elemental selenium having⁰At the time of production of the glass
Value calculated by dividing by the total weight of selenium added,
In other words, the amount of selenium added to the glass raw material during manufacturing
Selenium-containing colored soda-lime-silica glass
Elemental selenium contained⁰Is the ratio of
N Se⁰The higher the yield of selenium-containing colored
Elemental selenium Se in lime-silica glass⁰For light absorption
Increases the absorption of light around 500 nm wavelength, from pink to red
In addition to providing a stable warm coloration,
Use efficiency is increased. In the present invention, the absorbance ratio is defined as an elemental cell.
Ren Se⁰Absorbance at a wavelength of 500 nm due to light absorption of
Selenium anion Se^2-430nm wavelength due to light absorption
It is the value divided by the absorbance, and the elemental selenium Se⁰Absorbance of
The larger the ratio, that is, the more light absorption near the wavelength of 500 nm
The stronger the selenium-containing colored soda-lime silica glass is peach
Unnecessary selenium anion Se that shows color to red color^2-To
The brownish color tone becomes weaker. Conversely, elemental selenium Se
⁰Is smaller, that is, the selenium anion Se
^2-Strong absorption around a wavelength of 430 nm due to light absorption of
The color of the dark brown color becomes stronger,
Light transmittance decreases, and pink to reddish warm color appears
A predetermined color tone of weak color cannot be obtained. The oxygen partial pressure in the glass melt is
Is the index of the amount of free oxygen in glass.
The melt is under oxidizing conditions. Conversely, the lower the oxygen partial pressure, the lower the gas pressure.
The lath melt is under reducing conditions. Of oxygen partial pressure
The measurement was performed with a glass viscosity of 10 when melted.^ThreePa · s or less
It is preferable to measure in the glass manufacturing process.
The effect of oxygen diffusion in the melting atmosphere
Is low and the heat resistance of the oxygen partial pressure measuring device is 140
The measurement is preferably performed on a glass melt at 0 ° C. [0017] Selenium-containing colored soda-lime silica glass
In the production, the amount of oxidizing agent added, for example, sodium nitrate
The amount of lithium and the amount of reducing agent added, e.g.
By adjusting the amount of bon, one of the molten glass in the manufacturing process
Oxygen partial pressure at 400 ° C. is 1 × 10^TwoPa or more, 1 ×
10^FourBy controlling within the range of Pa or less,
Containing selenium-containing colored soda-lime-silica glass,
Effective coloring of desired color tone of pink to red warm color tone
Elemental selenium Se⁰Yield of 5.0 wt% or more
Selec- tion that inhibits the coloring
Anion Se^2-Yields can be kept low.
You. As a result, the produced selenium-containing colored
Elemental selenium Se in lime-silica glass⁰Wave by
The light absorption around 500 nm in length increases, and elemental selenium Se
⁰The absorbance at a wavelength of 500 nm due to light absorption of selenium
Ion Se^2-Absorbance of wavelength 430nm due to light absorption of
An absorbance ratio of 1.0 or more, which is a divided value, is obtained. The oxygen partial pressure in the glass melt is 1 × 10^TwoPa
Above 1 × 10^FourBy controlling within the range of Pa or less
Contained in selenium-containing colored soda-lime-silica glass
Elemental selenium Se as a coloring active ingredient⁰4. yield of
By increasing to 0 wt% or more, the type of coexisting ions and
Melting temperature, melting atmosphere, annealing temperature and annealing time
What selenium valence is unstable for any glass manufacturing conditions
And without being affected by selenium-containing colored soda
Continuously stable color in lime silica glass production
And light transmittance can be obtained. The coloring active ingredient Len Se⁰Income
Selenium added to glass raw materials
Can be used more efficiently. The oxygen partial pressure is 1 × 10^FourArea higher than Pa
In the region, selenium is oxidized to selenate, ie, SeO
_Four ^Twoー, selenite, ie, SeO_Three ^2-Next, selenium yang i
ON, Se⁶⁺And Se⁴⁺Increases in elemental selenium Se
⁰Of elemental selenium near the wavelength of 500 nm
Se⁰Absorption decreases and the desired pink to reddish coloration
No longer available. Further, elemental selenium Se⁰Yield
By reducing, more is needed to obtain the desired color tone.
It is uneconomical because many selenium compounds need to be added.
You. On the other hand, when the oxygen partial pressure is 1 × 10^TwoLower than Pa
In the region, elemental selenium Se⁰The yield of
Anion Se^2-Around 430 nm
Intense amber color due to visual light absorption, elemental selenium S
e⁰Color from pink to red cannot be obtained.
In addition, the visible light transmittance is significantly reduced
It becomes difficult to use as window glass. That is, the oxygen partial pressure in the glass melt is set to 1 × 10
^TwoPa or more, 1 × 10^FourControl within the range of Pa or less
The obtained selenium-containing colored soda lime silica glass
Elemental selenium Se in steel⁰To 5.0 wt% or more
Selenium anion that enhances and inhibits the color tone of elemental selenium
N Se^2-Of elemental selenium Se⁰Light absorption
The absorbance at a wavelength of 500 nm due to the selenium anion S
e^2-Value divided by absorbance at 430 nm wavelength due to light absorption
And an absorbance ratio of 1.0 or more is obtained. [0024] BEST MODE FOR CARRYING OUT THE INVENTION The selenium-containing colored soda stone of the present invention
In the method for producing ash glass, the method for producing the glass
The addition ratio of selenium to the total weight of the raw materials is 5 to 500 pp
m. Effective for coloring when the addition rate is less than 5 ppm
Elemental selenium Se⁰Is insufficient and the desired color
Is difficult to obtain. Assuming that the addition rate is more than 500 ppm
The visible light of selenium-containing colored soda-lime glass obtained
The transmittance does not change, and only the amount of selenium volatilizing during production is large.
It becomes. The method of producing glass according to the present invention
Float method, roll-out method for producing flat glass
Used in glass manufacturing methods such as the method and duplex method
it can. An embodiment of the present invention will be described below.
However, the present invention is not limited by the following examples.
Absent. [0028] [Example] (Measurement of oxygen partial pressure)
Oxy Electron pressure device "RAP"
Using "IDOX" to refer to a mixture of Ni and NiO
And ZrO stabilized on the solid electrolyte_Two1400 using
Measured in ° C. In other words, the reference
The battery cell is formed by opposing the glass material and the glass material.
The oxygen partial pressure of the glass melt and the reference material
The potential difference caused by the oxygen partial pressure was measured with a voltmeter. What
Note that Ir or Pt is not applied to the measuring electrode that comes in direct contact with the glass melt.
Which noble metal was used. (Measurement of valence of selenium) The valence of selenium is Dotite DA
B colorimetric method and atomic absorption spectrophotometer (Hitachi, Ltd.
And model Z-5000). (Measurement of visible light transmittance)
Using a meter (model U-4000, manufactured by Hitachi, Ltd.)
Measures light transmittance in the wavelength range of 300nm to 800nm
And determined according to JIS Z8701-1995. (Example) Composition ratio, SiO_Two, 72wt%, Al_TwoO_Three,
2 wt%, MgO, 4 wt%, CaO, 9 wt%, Na
_TwoSoda lime silica glass raw material consisting of O, 13wt%
The selenium addition rate was 200 ppm based on the total weight of
Zinc selenite, ie, ZnSeO_ThreeAdd
Iron oxide to the total weight of the raw material of soda-lime-silica glass.
It was added so as to be 0.11% by weight. Then
To change the oxygen partial pressure of the molten glass,
Sodium nitrate was added as an agent at different addition rates.
That is, no addition, SiO in the raw material_Two3w for the weight of
It was added so as to be t% or 5 wt%. Next, reduction is performed to change the oxygen partial pressure.
Carbon as an agent was added at different addition rates. That is,
No addition, SiO in the raw material_Two0.00 for the weight of
5 wt%, 0.01 wt%, 0.02 wt%, or
0.05 wt% and added with sodium nitrate
Seven types of glass raw materials were prepared by combining the addition rates of carbon.
An electric furnace which was made at a temperature of 1450 ° C.
Melt for 3.5 hours and drop to 1400 ° C over 1 hour
After warming and holding for 30 minutes, pour it into a graphite mold
And cooled slowly in an electric furnace at 570 ° C. in the atmosphere. Slow cooling
For the glass after, the glass melt at 1400 ° C.
Oxygen partial pressure, selenium yield and glass plate thickness 5mm
The converted visible light transmittance was measured. Table 1 shows that SiO in the glass raw material was used._TwoAgainst the amount of
To add sodium nitrate and carbon
The above seven types of glass raw materials having changed in temperature were melted by heating.
Of the obtained oxygen for the oxygen partial pressure and the amount of selenium added
Elemental selenium and selenium anion in lime-silica glass
, Selenium cation yield, elemental selenium Se⁰Light absorption
The absorbance at a wavelength of 500 nm due to the selenium anion S
e^2-Value divided by absorbance at 430 nm wavelength due to light absorption
Assuming that the absorbance ratio and the glass plate thickness are 5 mm
This is a summary of the visible light transmittance. [0031] [Table 1] Embodiment 1 As shown in Example 1 of Table 1, the soda-lime silica gel
SiO in raw material_TwoSodium nitrate, based on the weight of
Heating using 3.0 wt% added, carbon-free raw materials
The oxygen partial pressure of the molten glass melt is 1.00 × 10^Four
Pa, soda lime paste obtained with respect to the amount of selenium added
Elemental selenium Se in lyca glass⁰, Selenium anion S
e^2-, Selenium cation Se⁶⁺And Se⁴⁺The yield of each
5.0 wt%, 0.0 wt%, 34.5 wt%
Was. Elemental selenium Se⁰Wavelength 500n due to light absorption of
m, the selenium anion Se^2-Waves due to light absorption
The absorbance ratio, which is the value obtained by dividing the absorbance at a length of 430 nm, is 1.
21 and the visible light transmittance were 83.9%. Example 2 As shown in Example 2 of Table 1, the soda-lime silica gel
SiO in raw material_TwoNo sodium nitrate added to the weight of
Heated and melted using raw materials without carbon
The oxygen partial pressure of the molten metal is 8.91 × 10^ThreePa, added
Element in soda-lime-silica glass obtained for the amount of len
Elementary selenium Se⁰, Selenium anion Se^{Two -}, Selenium Yang
On Se⁶⁺And Se⁴⁺Is 8.0 wt%,
0.5wt%, 26.5wt%, absorbance ratio 1.19
And the visible light transmittance was 84.2%. Example 3 As shown in Example 3 of Table 1, Si in the glass raw material
O_TwoNo sodium nitrate added, carbon,
Heat-melted gas using raw materials with 0.005 wt% addition
The oxygen partial pressure of the lath melt is 4.37 × 10^TwoPa added
In soda-lime-silica glass obtained for selenium content
Elemental selenium Se⁰, Selenium anion Se^{Two -}, Selenium yang
Ion Se⁶⁺And Se⁴⁺Of each was 6.5 wt.
%, 1.0 wt%, 9.5 wt%, absorbance ratio is 1.08
And the visible light transmittance was 80.3%. Example 4 As shown in Example 4 of Table 1, Si in the glass raw material
O_TwoNo sodium nitrate added, carbon,
Gala heated and melted using 0.01 wt% added raw material
The oxygen partial pressure of the melt is 1.05 × 10^TwoPa, added
Element in soda-lime-silica glass obtained for the amount of len
Elementary selenium Se⁰, Selenium anion Se^2-, Selenium Yang
On Se⁶⁺And Se⁴⁺Is 5.0 wt%, respectively.
1.5 wt%, 7.0 wt%, absorbance ratio is 1.01
And the visible light transmittance was 79.6%. Comparative Example 1 As shown in Comparative Example 1 of Table 1, Si in the glass raw material
O_Two5.0 wt% of sodium nitrate added to the weight of
Glass melt that is heated and melted using raw materials without the addition of carbon
Oxygen partial pressure is 1.87 × 10^FourPa, amount of selenium added
Elemental cell in soda-lime-silica glass obtained
Ren Se⁰, Selenium anion Se^2-, Selenium cation S
e⁶⁺And Se⁴⁺Are 2.5 wt% and 0.0
wt%, 38.5wt%, absorbance ratio 0.90 and acceptable
The visible light transmittance was 84.9%. Comparative Example 2 As shown in Comparative Example 2 of Table 1, Si in the glass raw material
O_TwoNo sodium nitrate added to the weight of carbon, carbon 0.
Glass melting heated and melted using 05wt% added raw material
The oxygen partial pressure of the liquid is 1.66 × 10^-1Pa, selenium added
Elemental Content in Soda-Lime-Silica Glass Obtained by Amount
Selenium Se⁰, Selenium anion Se^2-, Selenium cation
Se⁶⁺And Se⁴⁺Are 3.5 wt% and 8.
5 wt%, 1.0 wt%, absorbance ratio 0.70 and acceptable
The visible light transmittance was 54.5%. Comparative Example 3 As shown in Comparative Example 3 of Table 1, Si in the glass raw material
O_TwoNo sodium nitrate added to the weight of carbon, carbon 0.
Glass melt melted by heating using 02wt added raw material
The oxygen partial pressure of 1.70 × 10Pa, the amount of selenium added
Elemental selection in soda-lime-silica glass obtained
N Se⁰, Selenium anion Se^2-, S of selenium cation
e⁶⁺And Se⁴⁺The yields are 1.5 wt% and 3.5 w, respectively.
t%, 1.5wt%, absorbance ratio 0.89 and visible light
The transmittance was 73.2%. Summarizing each measurement result shown in Table 1,
Oxygen partial pressure 1 × 10^TwoPa or more, 1 × 10^FourRange below Pa
Soda lime paste shown in Examples 1 to 4 obtained when
Rica glass is elemental selenium Se⁰Yield
5.0% or more, selenium anion Se^2-Low yield
Was suppressed. Elemental selenium Se⁰Yield of 5.0% or less
Above, selenium anion Se^2-Yield is kept low
As a result, elemental selenium Se⁰Wavelength due to light absorption
The absorbance at 500 nm is determined by the selenium anion Se.^2-Light absorption
Absorbance divided by absorbance at 430 nm
Ratio becomes 1.0 or more, and elemental selenium Se⁰High yield
The desired warm tones of pink to red color were obtained. one
On the other hand, oxygen partial pressure is 1 × 10^TwoPa or more, 1 × 10^FourPa or less
Soda lime silica glass of Comparative Examples 1 to 3 out of the range
Is elemental selenium Se⁰Low yield of less than 5.0%
And the absorbance ratio was less than 1.0. In addition, Comparative Example 2 and
And in Comparative Example 3, the selenium anion Se^2-High yield
As a result, the visible light transmittance was significantly reduced. [0034] According to the present invention, the selenium-containing colored soda lime slurry of the present invention is provided.
In a method for producing kagarasu, a colored soda stone containing selenium is used.
During the production of ash silica glass, soda lime silica glass
Melt temperature when raw materials and selenium compounds are heated and melted
The oxygen partial pressure in the glass melt at 1400 ° C is 1.0
× 10^TwoPa or more, 1.0 × 10^FourWithin the following range of Pa
Adjust the amount of oxidizing and reducing agents
The amount of selenium-containing
Elemental selenium Se contained in colored soda-lime-silica glass
⁰Is 5.0 or more, and the selenium-containing colored
Elemental selenium Se in lime-silica glass⁰Light absorption
The absorbance at a wavelength of 500 nm due to the selenium anion S
e^2-Value divided by absorbance at 430 nm wavelength due to light absorption
Is 1.0 or more, and elemental selenium Se
⁰Pink to red due to light absorption at a wavelength of 500 nm
The coloration of the warm color tone and the specified visible light transmittance
can get. Selenium-containing colored soda-lime silica of the present invention
The elemental selenium S in the glass is obtained by the method for producing the glass.
e⁰The desired color and visible light transmission
Adjustment of glass manufacturing conditions such as furnace operation conditions to obtain excess ratio
However, since it is easier than before, the colored soda stone product
The color tone of ash-silica glass is stable from the start of glass production.
Start-up time to production can be shortened, improving productivity
I do.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Michishita             1510 Oguchicho, Matsusaka City, Mie Prefecture Central             Inside Glass Laboratory, Glass Co., Ltd. F term (reference) 4G062 AA01 BB03 DA06 DA07 DB03                       DC01 DD01 DE01 DF01 EA01                       EB03 EB04 EC03 EC04 ED03                       EE03 EE04 EF01 EG01 FA01                       FA10 FB01 FC01 FD01 FE01                       FF01 FG01 FH01 FJ01 FK01                       FL01 GA01 GB01 GC02 GD01                       GE01 HH01 HH03 HH05 HH07                       HH09 HH11 HH12 HH13 HH15                       HH17 HH20 JJ01 JJ03 JJ05                       JJ07 JJ10 KK01 KK03 KK05                       KK07 KK10 MM01 NN05

Claims (1)

Claims 1. A method for producing a selenium-containing colored soda-lime silica glass containing selenium as a coloring component,
After adding at least a selenium compound as a coloring component to the raw material of soda lime glass, adding an oxidizing agent and a reducing agent, and then heating and melting to form a glass melt, the amounts of the oxidizing agent and the reducing agent are adjusted. Thus, the oxygen partial pressure of the glass melt at 1400 ° C. is 1 × 10 ² Pa or more,
The yield of elemental selenium calculated by dividing the weight of elemental selenium contained in the soda-lime-silica glass obtained by cooling the glass melt under control of × 10 ⁴ Pa or less by the total added weight of selenium. Selenium content, wherein the ratio is not less than 5.0 wt%, and the absorbance ratio calculated by dividing the absorbance at 500 nm of the soda-lime silica glass by the absorbance at 430 nm is not less than 1.0. A method for producing colored soda lime silica glass.