JPS61136935A - High manganese-content frit for decoloring - Google Patents

Abstract

PURPOSE:To obtain the titled frit of high manganese content which is reductive and used for decoloring molten colored soda-lime glass by composing the frit of a mixture obtained by blending SiO2, Na2O, MnO2, and B2O3 in a specified ratio and wherein the content of Mn<3+> in the manganese is regulated to more than a specified value. CONSTITUTION:A frit contains 45-60wt% SiO2, 15-30wt% Na2O, 1-38wt% MnO2, and 0-15wt% B2O3, and the ratio of Mn<3+> to the whole manganese is regulated to >=20%. The frit which is highly meltable and has high clarity is obtained, and used for decoloring colored soda-lime glass.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a high manganese-containing frit for color erasing. More specifically, the present invention relates to a high manganese-containing frit for decolorizing colored soda-lime glass having high meltability and high clarity.

(Prior Art) As a conventional technology for decoloring molten glass, there is a problem with inconveniences contained in common soda-lime glass, especially soda-lime glass used for table glass containers or packaging glass bottles. For example, when decoloring the green color of Fez÷ion, 5e-Co component, M(1-Co
By adding the components to a raw material batch before melting and melting them, colors that are optically complementary colors are developed and then discolored. On the other hand, by melting the glass under strongly oxidizing conditions, the content ratio of Fe2+ ions, which have a strong green coloring property, was lowered and the coloration was prevented. Therefore, in the prior art, there is no technical concept of decolorizing the glass in a part of the feeder (therefore, there are no documents related to this at all).

(Problems to be Solved by the Invention) Today, when energy and resource conservation are being called for, there is a strong desire in this industry to increase the melting efficiency in glass melting and to increase the amount of molten glass pulled up with high efficiency. Ta.

In order to meet the above demand (as a result of extensive research, the present inventors have discovered that soda-lime glass (also known as rFL
AMBERGLASS, hereinafter referred to as "Flambar glass". ), on the other hand, when it comes to glass for tableware or packaging glass, the coloring caused by its reducing properties, such as the green color of Fe" ions, can significantly reduce the product quality or meet product standards. In view of the fact that this condition was largely overlooked, we developed a specific high-manganese-containing frit that could effectively eliminate this drawback.

The object of the present invention is to provide colorless soda-lime glass particularly for use in table glassware or packaging glass bottles with a so-called high energy-saving effect, and which has higher and stronger melting ability and fining ability. An object of the present invention is to provide a high-manganese-containing frit for efficiently eliminating undesirable coloring in a portion of a feeder in soda-lime glass melted under reducing conditions.

That is, we have succeeded in developing a frit that efficiently eliminates the undesirable coloration caused by the strongly reducing molten soda lime glass, or "Flambar glass," and we propose this as the present application.

(Means for Solving the Problems) The technical gist of achieving the above object efficiently is to provide a high manganese-containing frit that is effective in decolorizing molten colored soda-lime glass in a reducible manner, 5i02 4
5 to 60% by weight of Na2O15 to 30'' MnO21 to 38 B20.
n''/total Mnl) is 20% or more.

More specifically, soda-lime glass is added and melted at a constant weight ratio in a relatively short part of the feeder to a melt of "Flambar glass" which has high meltability and high clarity. A high manganese-containing frit having a specified composition and meeting specific conditions is used to effectively eliminate the characteristic green color of the "flamber glass" and obtain an almost colorless and transparent soda-lime glass. This is related to.

(Function) For manufacturing table glassware or packaging glassware,
With ordinary soda-lime glass melting means, due to its melting ability, the molten glass is approximately 0.5 to 0.6 times the kiln capacity/d.
The limit was to allow part of the feeder to flow at a rate of ay. This is because if the flow rate is higher than that, the glass will not be sufficiently cleaned and some undissolved matter will be mixed in, resulting in bubbles and the like being mixed into the glass, resulting in a defective glass. However, the so-called "Flambar glass" mentioned above has excellent meltability and clarity, so it is possible to obtain a glass flow rate of approximately 0.8 to 1.0 times the kiln capacity/day. It is.

Therefore, a fixed amount (e.g. 0
．． Specific frits (2-10%) require the ability to melt quickly and mix homogeneously and discolor at relatively short feeder lengths of about 4-10 meters. A specific frit that has that ability is 5i02 45-60% by weight Na2O15-
It is necessary to satisfy the conditions that it contains 30 8 MnO21-38'' 8203 0-15 N and that [Mn''/total Mnl is 20% or more.

That is, in the frit of the present invention, 5iOz is a forming component of the frit glass, and when it exceeds 60% by weight, the meltability in the feeder deteriorates, and when it is less than 45%,
Durability as frit glass decreases. The reason for adding 15 to 30% by weight of NatO is to provide a stable glass structure and to provide melting properties that enable homogeneous mixing.

The manganese component is a component that plays a particularly important role in decolorizing so-called "flamber glass," and by melting into the glass, manganese ions (Mn2÷,
It exists in the state of Mn'÷), and the Mn3÷ acts on the iron ions (Fe2+) in the molten glass, causing a reaction of Mn"÷+Fe" -+ Mn'' +Fe3÷, and some Mn3+ ions remain. By doing so, efficient color erasure is achieved, and MnO2 equivalent is 1 to 38 f[
A range of 1% is required. When less than 1% by weight, M11
If the required amount of 3+ cannot be secured and the initial objective cannot be achieved, and even if the weight exceeds 38%, M
It is meaningless because the absolute necessary amount for erasing n'' does not asymptotically increase to a constant value.

Furthermore, the limiting condition that [Mn''/total Mnl is 2θ% or more is an essential condition for the decolorizing effect, and if the value is less than 20%, the undesirable Fe2 ÷ ions will be converted into Fe3+ ions. Not only is it not possible to obtain a sufficient amount of Mn"+ ions, but it is also difficult to obtain the presence of a small amount of Mn"+ ions for decoloring.

In addition, the value of [Mn3''/total Mnl can be adjusted by the raw material mixing ratio and frit melting conditions (for example, melting atmosphere), and especially by melting under strong oxidizing conditions,
can be increased.

And B20. The purpose of this is to assist the meltability of the frit glass during molding and to improve the melt mixability of the frit, and if it exceeds 15% by weight, its effect will be significantly reduced.

In addition, as other components, CaO%M of 10% by weight or less
an alkaline earth metal oxide such as gO1BaO, up to 5% by weight of an alkali metal oxide such as 201Li20, some color tone adjusting component (e.g. a compound such as 5esCos 1'J+), or up to 3% by weight of a frit composition. It may also contain an adjustment component (for example, Al20z, etc.).

(Example) Next, Examples of the present invention will be described to explain the present invention in further detail.

Table 1 Each batch having the raw material composition shown in Table 1 above was prepared and melted in a crucible furnace in an oxidizing atmosphere to create a high manganese-containing frit having the composition and properties shown in Table 2 below. .

Table 2 Each frit obtained in this way was melted with a melting capacity of 20
SiO272.2% by weight Al2O32.2〃 CaO10.8" MgOO,2〃 Na2Ok2.5 〃 20 1.5 #Fe2O-0 melted in a 0 ton/day glass melting kiln
, 05" Other 0.25# flow in a feeder section of colored soda-lime glass with a [Fe"/total Fe ratio of about 50% (flow rate = about 1
80 tons/day), approximately 2.5 kg/e+in
was added in the amount added, melted, and mixed. The glasses thereby obtained exhibited the color properties listed in Table 3 below.

Table 3: The color characteristics of ordinary printed glass are approximately: stimulation purity 2.0% or less, brightness 75% or more (glass thickness = 20%).
mm), and as a comparative example of the present invention, the color characteristics of "Flambar glass" without adding frit of the present invention are: dominant wavelength 484.8n+s, excitation purity 7.4%, It was a green glass with a color characteristic of 76.2% brightness.

Furthermore, as shown in FIG. 1, the transmittance curve of Example 1 is close to that of flint glass, which is colorless and transparent, and there is a large difference in absorption characteristics from that of "7 lumber glass". And, compared to the melting flow rate (Max>) of the ordinary soda-lime glass melting means in the glass melting kiln, which was about 120 tons/daν, the melting flow rate was increased by about 1.5 times. At the same time, good results were obtained in which meltability and clarity were significantly improved.

(Effects of the Invention) As described above, according to the present invention, it is possible to obtain meltability and clarity that are approximately 1.5 times higher than the melting ability of ordinary soda lime glass, and the color tone is different from that of ordinary soda lime glass. It was possible to obtain a colorless and transparent glass.

Therefore, the ability to save energy in glass melting, which consumes a large amount of energy, is a great contribution not only to those skilled in the art but also to society.

[Brief explanation of drawings]

FIG. 1 shows the transmittance curves of Example 11 flint glass and "7 lumber glass". ■ Example 1 2 Printed glass 3 "Flambar glass" Patent applicant Ishizuka Glass Co., Ltd. No changes to the contents of the engraving C of the drawings) Figure 1: JL length (nm1 procedural amendment format)

Claims (1)

[Claims] (1) Contains SiO_2 45-60% by weight, Na_2O 15-30〃 MnO_2 1-38〃 B_2O_3 0-15〃, and the proportion of Mn^3^+ in the total manganese is 20% or more. A high manganese-containing frit for decolorizing colored soda-lime glass melted with reducing properties.