JPS623041A - Production of aluminosilicate glass containing rare earth metal - Google Patents

Abstract

PURPOSE:To shorten the glass smelting time and to reduce the production cost of the titled silicate glass, by melting and vitrifying a mixture of secondary shirasu, Al2O3 and Y2O3 concentrate. CONSTITUTION:A mixture of 30-53(wt)% secondary shirasu, 9-30% Al2O3 and 23-54% Y2O3 concentrate is vitrified by melting. The above mixture may further contain <=13% TiO2 and/or <=9% ZrO2. The addition of TiO2 is effective to improve chemical resistance, corrosion resistance and weathering proofness, however, crystallization takes place at >13% to fail the production of glass. The addition of ZrO2 is effective to improve chemical resistance, corrosion resistance, weathering proofness, mechanical properties and heat-resistance, however, crystallization takes place at >9% to fail the production of glass.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing rare earth-containing aluminosilicate glasses which can be produced by bath melting at temperatures below 1550'C.

Prior Art Aluminosilicate glass made of silica and alumina has high durability, good mechanical strength, and excellent corrosion resistance and weathering resistance. However, obtaining this thread glass requires very high temperatures.

In an electric furnace using a general silicon carbide heating element, 155
Since the temperature is limited to about 0°C, this type of glass could not be manufactured by a general melting method using an electric furnace.

Generally, when alkali oxides and alkaline earth oxides are contained, the melting temperature decreases, and at a temperature of about 1550°C,
It becomes possible to manufacture glass using an electric furnace that uses general silicon carbide as a heating element. However, when alkali oxides and alkaline earth oxides are included, heat resistance and mechanical properties decrease.

There is a problem in that the properties such as chemical resistance, corrosion resistance and weathering resistance are deteriorated.

The present inventors previously proposed that 155
It was revealed that glass can be produced using a general electric furnace at about 0°C, and that the resulting glass has excellent mechanical properties. [Journal of the American Ceramics Association Vol. 61, 247
-249 pages (1978)] However, since separated Y2O3 is expensive, there has been an emphasis on increasing the cost.

In order to solve this problem, the present inventors first developed Y2O
When researching the use of yttrium concentrate, which is an intermediate refined product for producing 3, it was found that yttrium concentrate obtained from YzOs raw ore, for example, 11t&'t from 7th time, contains several 10% of Y2O3,
The rest is Dy20. , Nd2O,r CeO2+Ho
O+ Yb O, Sm2O3+ La20. ＋G
Rare earth oxides such as d2O, Er20゜, etc. are used as additives in place of Y2O3 to produce aluminosilicate glass. There is no negative effect on glass properties, especially alkali resistance. (2) It was found that the use of this product lowers the melting point of the glass by about 50°C compared to the case of using separated Y2O3, and the price is 100,000 yen, making it cheaper. (Patent application 18049/1982)
No. 8) As a result of repeated research into cost reduction, the present inventors discovered that the volcanic ash shirasu, which is widely dispersed for use in lighting, is mainly composed of aluminosilicate glass, and that the secondary component of shirasu is We focused on the fact that the chemical composition of secondary shirasu, which is a sediment product, is almost constant, and investigated how to utilize this fact. The chemical composition of secondary shirasu is as follows.

5i02 82.59 mol% 75.87 weight'I
t%At20S9.16 # 14.28
#Fe2O,0,92# 2.24 gCaO
1,54# 1.32 #JOO,49#
0.30 zNa20 3.35 t
3.18 zK20 1.95 1 2
．． 80 #In this way, the total component of 5i02 and Al2O is about 92 mol%, and most of it is aluminosilicate, so Y2O5 concentrate, secondary shirasu and aluminum
When we tried to manufacture glass using l2O3 as a raw material, we found that in addition to these components, Fe2O3+ CaO, MgO, and Nd2O contained in the secondary shirasu listed in the table above were also found.
.

It is possible to obtain a glass containing about 5 moles or less of K2O in total, and if this is used as a raw material, 5in2+A! 20.
It was found that the glass melting height could be reduced to about 3 times compared to the case where the raw material was used as raw material. The present invention was completed based on these findings.

The gist of the present invention is 30-53% by weight of secondary shirasu.

Aj2059-30] 1-ji%, Y2O3 concentrate 23-54i-11% as raw materials, and a method for producing rare earth-containing aluminosilicate glass characterized by heating and melting a mixture thereof to vitrify it. .

In the present invention, Y2O3 concentrate refers to Y2O3 concentrate.
It is an intermediate purified product obtained from a raw ore of 2O, such as xenotime, by a sulfuric acid decomposition method or an alkali decomposition method. Using the alkaline decomposition method, xenotime is gradually heated to 400°
Add to the melted caustic soda in bath C. The reaction is exothermic and after the reaction is completed, it is cooled and the reactants are extracted with water and extracted with sodium phosphate,
Excess alkali is removed. The obtained rare earth hydroxide is dissolved in a small amount of hydrochloric acid, oxalic acid is added to this solution to form a rare earth oxalate salt, and this is calcined at 900° C. to obtain a yttrium concentrate. An example of the analysis is as follows.

Analysis example of yttrium concentrate (%), that is, the constituent elements in the ore! These substances are contained without any separation operation.

In the glass raw material of the present invention, if the secondary shirasu content is less than 30% by weight, the melting temperature becomes high and vitrification cannot be achieved at 1550°C. Moreover, if it exceeds 53%, the characteristics of the rare earth-containing aluminosilicate glass cannot be exhibited.

Aj! 20. If it is less than 9% by weight, it will not vitrify,
:If it exceeds 30 wt'i%, the melting temperature becomes high and l55
Glass cannot be obtained at 0°C.

v20! If the I concentrate is less than 23% by weight, the characteristics as a glass containing rare earth oxides cannot be exhibited, and at 1550°C, a glass cannot be obtained;
! %, crystallization occurs and glass cannot be obtained.

Therefore, the secondary Shirasu is 30-53% by weight Al2O.

is 9 to 30 weights! 1%, Y2O3 concentrate is 2
Amounts in the range 3-54% by weight are required.

In addition to the above raw materials, if necessary, Tie2.13 weight 1
% and/or Zr0□9% by weight may be added. Addition of Tie2 has the effect of increasing chemical resistance, corrosion resistance, and weathering resistance, but if it exceeds 13"ILf[%, it will crystallize and no glass will be obtained. Addition of ZrO2 will improve chemical resistance, corrosion resistance, and weathering resistance. sex.

It works to improve mechanical properties and heat resistance, but if it exceeds 9% by weight, it will crystallize and glass cannot be obtained.The above raw materials melt and vitrify at temperatures below 1550"C, forming rare earth-containing aluminosilicon. An acid salt glass is obtained.

Example 1゜Secondary whitebait 51゜93% i%, Al2O, 12,60
weight%.

A mixture of Y2O and concentrate at a ratio of 35.47% was placed in a platinum rutsuho and heated at 1500° in an electric furnace.
After heating and melting at C for 2 hours, it was poured onto an aluminum plate and allowed to cool. A light brown, bubble-free, transparent glass was obtained.

The coefficient of thermal expansion of this glass is 53°I x 10-”/'C
It has a much lower coefficient of thermal expansion than ordinary window glass. Therefore, the thermal shock resistance when used as window glass is that of ordinary soda lime glass (its thermal expansion coefficient is approximately 90 x
IF'1/'C). When this glass was molten, the platinum crucible was taken out of the furnace, and glass fibers were made into glass fibers according to the instructions.
Glass fibers with a length of m or more could be easily obtained.

Density is 3.258 f/Cm5, Vikers hardness is 86
0 Ky/ws and is a hard glass.

Its chemical composition, calculated from the raw material ratio, is SiO□3
9.40% by weight, (% is weight below), Al2O
.

20.02%, Fe, 031.16%, CaO0
,69%, Mg00.16%, Na2O1,65%
, K2O1,45%, Ittria Concentrate)
Al at 35.47%.

Example 2゜Secondary shirasu 36.08% by weight, Al2O,26,03
Part i.

A mixture of Ittria Concentrate at a ratio of 37.89 Xi% was placed in a platinum rutsuho and heated to 145% in an electric furnace.
0°C for 1.5 hours, then increase the electric furnace temperature to 1500°C.
After heating and melting it for 20 minutes, it was poured onto an aluminum plate and left to cool. A light brown transparent glass was obtained. The coefficient of thermal expansion of this glass is 53.0XIO-'c, and the density is 3.456? /cm'.

Example 3゜Secondary whitebait 40.28㊃1%, Al2O, 17.5
3% by weight.

A mixture of Ittria Concentrate 42.19i and 11% was placed in a platinum crucible, and heated to 150 ml in an electric furnace.
After heating and melting at 0°C for 1.5 hours, it was poured out onto an aluminum plate and allowed to cool. A light brown, bubble-free, transparent glass was obtained. The coefficient of thermal expansion of this glass is 59.2
10-' °C, density is: 3.521? /Ca
It was 11'. Further, this glass could also be easily made into fibers as in Example 1.

Example 4゜Secondary whitebait 30.19% by weight, A420.18.26
weight%.

Ittria concentrate 40.00% by weight, Ti
e.

The mixture at a ratio of 11.55% by weight was placed in a platinum crucible, and this was heated and melted at 1550°C for 1.5 hours in an electric furnace. This melt was poured onto an aluminum plate and allowed to cool.

A clear, bubble-free glass with a reddish brown color was obtained. The coefficient of thermal expansion of this glass is 56 x 10-' 1/
``C1 density was 3.61217 cm5.

Example 5 Secondary Shirasu 35.12ffk: Amount %, A120317
．． 06% by weight.

Ittria Concentrate 39.11 f (匍%, Z
The mixture at a ratio of r028.71% by weight was placed in a platinum crucible, and this was heated and melted in an electric furnace at 1550°C for 1.5 hours. This melt was poured onto an aluminum plate and allowed to cool. A light brown, bubble-free, transparent glass was obtained. The coefficient of thermal expansion of this glass is 53. OX 10-
'1/' (The density was: 6219/cm5.

Effects of the Invention According to the method of the present invention, since secondary shirasu and ittria concentrate are used, aluminosilicate containing Y2O3 gold can be obtained at low cost, and the melting temperature is low, so it can be melted in a general electric furnace. Moreover, the heating time is short, and the resulting glass has an excellent effect of retaining the properties of aluminosilicate glass. Furthermore, the resulting glass has a high modulus of elasticity and high alkali resistance, so it can be used in combination with cement. And Fe2
It has ultraviolet absorption properties because it contains o5 and CeO2,
Sunroom windows as UV absorbing tinted transparent glass.

It can also be effectively used as roof windows for automobiles, ultraviolet absorbing containers for various physical and chemical applications, and window materials.

Patent applicant: Director of the Science and Technology Agency, Inorganic Materials Research Institute, Bian [( After Yu Fuji −−j:

Claims (1)

[Claims] 1) Secondary shirasu 30-53% by weight, Al_2O_3
9-30% by weight, Y_2O_3 concentrate 23
A method for producing rare earth-containing aluminosilicate glass, which comprises using ~54% by weight as raw materials and heating and melting a mixture thereof to vitrify it. 2) Secondary shirasu 30-53% by weight, Al_2O_3
9-30% by weight, Y_2O_3 concentrate 23
A method for producing a rare earth-containing aluminosilicate glass, which comprises adding TiO_2 in an amount not exceeding 13 wt% or ZrO_2 in an amount not exceeding 9 wt% in addition to ~54 wt%, and heating and melting this to vitrify it.