JP2014111544A - Production method of glass raw material crude lysate, and production method of optical glass - Google Patents

Production method of glass raw material crude lysate, and production method of optical glass Download PDF

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JP2014111544A
JP2014111544A JP2014052303A JP2014052303A JP2014111544A JP 2014111544 A JP2014111544 A JP 2014111544A JP 2014052303 A JP2014052303 A JP 2014052303A JP 2014052303 A JP2014052303 A JP 2014052303A JP 2014111544 A JP2014111544 A JP 2014111544A
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raw material
glass raw
glass
cylindrical tube
melt
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JP5784166B2 (en
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Hiroyuki Sakawa
博幸 坂和
Yusuke Uehara
友輔 上原
Magonori Oguma
孫権 小熊
Takumi Ito
匠 伊藤
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Hoya Corp
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    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03BMANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/02Melting in furnaces; Furnaces so far as specially adapted for glass manufacture in electric furnaces, e.g. by dielectric heating
    • C03B5/033Melting in furnaces; Furnaces so far as specially adapted for glass manufacture in electric furnaces, e.g. by dielectric heating by using resistance heaters above or in the glass bath, i.e. by indirect resistance heating
    • C03B5/0338Rotary furnaces
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03BMANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • C03B5/20Bridges, shoes, throats, or other devices for withholding dirt, foam, or batch
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03BMANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B3/00Charging the melting furnaces
    • C03B3/02Charging the melting furnaces combined with preheating, premelting or pretreating the glass-making ingredients, pellets or cullet
    • C03B3/026Charging the melting furnaces combined with preheating, premelting or pretreating the glass-making ingredients, pellets or cullet by charging the ingredients into a flame, through a burner or equivalent heating means used to heat the melting furnace
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00Technologies relating to the processing of minerals
    • Y02P40/50Glass production, e.g. reusing waste heat during processing or shaping
    • Y02P40/57Improving the yield, e-g- reduction of reject rates

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Glass Melting And Manufacturing (AREA)
  • Glass Compositions (AREA)

Abstract

PROBLEM TO BE SOLVED: To suppress coloration of an optical glass produced by using a glass raw material crude lysate.SOLUTION: In a production method of a glass raw material crude lysate, the glass raw material crude lysate is produced through at least a raw material supply step for supplying a glass raw material into a raw material treating member 20 from an input port 22 of the raw material treating member 20, a heating/melting step for moving the glass raw material supplied into the raw material treating member 20 from the input port 22 to an outflow port 24, so as to be simultaneously heated and melted, and a solidifying step for cooling and solidifying a melt of the glass raw material flowing down from the outflow port 24; wherein, when moving the glass raw material from the input port 22 to the outflow port 24 in the raw material treating member 20, the glass raw material is allowed to stay temporarily in the raw material treating member 20. A production method of an optical glass using the method is also provided.

Description

本発明は、ガラス原料粗溶解物の製造方法および光学ガラスの製造方法に関するものである。   The present invention relates to a method for producing a glass raw material crude melt and a method for producing optical glass.

ガラス原料を加熱、溶融してガラスを製造する場合、溶融物が坩堝を強く侵蝕する。そして、この際の侵蝕力は、ガラス原料がガラス化する際に顕著であるが、ガラス化した後はさほど大きくは無い。このため、ガラスを製造する場合において、ガラス原料を一旦、粗溶解した後、急冷して得られた粗溶解物を作製し、この粗溶解物を用いて本溶解する製造方法が利用されている。この製造方法では、ガラス原料をそのまま用いて本溶解する製造方法と比べて、本溶解時の坩堝の侵蝕を抑制できる。このような製造方法は、坩堝材料として使用される白金に対する侵蝕力の大きい光学ガラスを製造する場合に利用されている。   When a glass raw material is heated and melted to produce glass, the melt strongly erodes the crucible. The erosion force at this time is remarkable when the glass raw material is vitrified, but is not so great after vitrification. For this reason, in the case of producing glass, a production method is used in which a glass raw material is roughly melted once, then a crude melt obtained by rapid cooling is prepared, and this coarse melt is used for main melt. . In this manufacturing method, the crucible erosion during the main melting can be suppressed as compared with the manufacturing method in which the glass raw material is used as it is for the main melting. Such a manufacturing method is used when manufacturing an optical glass having a large erosive force against platinum used as a crucible material.

ここで、粗溶解物の製造には、ガラス原料を加熱して粗溶解するための石英管を備えた原料溶解炉が用いられる(特許文献1,2参照)。この原料溶解炉は、中心軸を水平方向に対して一定の角度を成すように傾斜させて配置した石英管と、この石英管を加熱する抵抗発熱体等とを備えている。そして、粗溶解物を製造する場合、まず、石英管の一方の開口部(投入口)からガラス原料を投入する。そして、投入口よりも鉛直方向下方側に位置する他方の開口部(流出口)側へと、ガラス原料を移動させながら、ガラス原料を加熱・溶解する。そして、融液状となったガラス原料を、流出口の下方に配置された水槽中に投入し、急冷することで、粗溶解物を得る。   Here, a raw material melting furnace equipped with a quartz tube for heating and roughly melting a glass raw material is used for the production of the coarse melt (see Patent Documents 1 and 2). This raw material melting furnace includes a quartz tube arranged with its central axis inclined at a certain angle with respect to the horizontal direction, and a resistance heating element for heating the quartz tube. And when manufacturing a coarse melt, first, glass raw material is supplied from one opening part (input port) of a quartz tube. And a glass raw material is heated and melt | dissolved, moving a glass raw material to the other opening part (outflow port) side located in a perpendicular direction lower side rather than an injection port. And the glass raw material used as the melt state is thrown into the water tank arrange | positioned under the outflow port, and a rough melt is obtained by quenching.

特開昭62−123027号公報JP-A-62-213027 特開平1−119522号公報JP-A-1-119522

しかしながら、特許文献1,2に例示されるような従来のガラス原料の加熱・溶解に用いられる石英管は、内周面が平滑で凹凸の無い面からなる単なる円筒管である。このため、投入口から石英管内に投入された原料が、投入口側から流出口側へと移動する際に、その移動が全く阻害されない。すなわち、原料は、石英管内を加熱・溶解しながら、石英管内にて滞留することなく投入口側から流出口側へとスムーズに移動し、流出口から水槽へと流れ落ちることになる。このため、石英管内にて原料を長時間に亘って加熱・溶解することができない。   However, the conventional quartz tube used for heating and melting the glass raw material as exemplified in Patent Documents 1 and 2 is a simple cylindrical tube having a smooth inner peripheral surface and no uneven surface. For this reason, when the raw material thrown into the quartz tube from the inlet port moves from the inlet side to the outlet side, the movement is not hindered at all. That is, the raw material smoothly moves from the inlet side to the outlet side without staying in the quartz tube while heating and melting in the quartz tube, and flows down from the outlet to the water tank. For this reason, a raw material cannot be heated and melt | dissolved for a long time in a quartz tube.

しがたって、粗溶解物を製造する際に、ガラス原料の加熱・溶解が不十分となり、粗溶解物のガラス化度合が低くなりやすい。すなわち、粗溶解物の白金坩堝に対する侵蝕力は、ガラス化度合が最も低いガラス原料により近づくことになる。このため、得られた粗溶解物は、ガラス原料と比べて白金に対する侵蝕力は大幅に低下しても、本溶解時に侵蝕によって混入した白金に起因する着色が生じ易くなる。   Therefore, when manufacturing the coarsely melted product, the heating and melting of the glass raw material becomes insufficient, and the vitrification degree of the crudely melted product tends to be low. That is, the erosion force of the coarsely melted material on the platinum crucible approaches the glass raw material having the lowest vitrification degree. For this reason, even if the obtained coarse melt | dissolution material reduces the erosion power with respect to platinum significantly compared with a glass raw material, it becomes easy to produce coloring resulting from platinum mixed by erosion at the time of this melt | dissolution.

このような問題を解決するためには、石英管内のガラス原料をより高温で加熱・溶解することも考えられる。しかしながら、通常、光学ガラスには、様々な種類の金属が含まれている。そして、これらの金属のうち、いくつかの金属は、より高温で加熱されると還元され、その結果、光学ガラスを着色させてしまう場合もある。   In order to solve such a problem, it is conceivable to heat and melt the glass material in the quartz tube at a higher temperature. However, optical glasses usually contain various types of metals. Among these metals, some metals are reduced when heated at higher temperatures, and as a result, the optical glass may be colored.

本発明は、上記事情に鑑みてなされたものであり、ガラス原料粗溶解物を用いて製造される光学ガラスの着色を抑制できるガラス原料粗溶解物の製造方法およびこれを用いた光学ガラスの製造方法を提供することを課題とする。   This invention is made | formed in view of the said situation, The manufacturing method of the glass raw material crude melt which can suppress coloring of the optical glass manufactured using a glass raw material crude melt, and manufacture of optical glass using this It is an object to provide a method.

上記課題は以下の本発明により達成される。すなわち、
本発明のガラス原料粗溶解物製造方法は、一方の端部に投入口を備え、他方の端部に流出口を備え、投入口が流出口よりも鉛直方向に対して上方側に位置するように配置され、かつ、筒状および樋状から選択される形状を有する原料処理部材の投入口から、ガラス原料を原料処理部材内に供給する原料供給工程と、原料処理部材内に供給されたガラス原料を、投入口から、流出口へと移動させつつ加熱・溶解する加熱・溶解工程と、流出口から流れ落ちるガラス原料の融液を、冷却して、固化する固化工程と、を少なくとも経てガラス原料粗溶解物を製造し、原料処理部材内の投入口から流出口側へガラス原料を移動させる際に、原料処理部材内においてガラス原料を一時的に滞留させることを特徴とする。
The above-mentioned subject is achieved by the following present invention. That is,
The glass raw material crude melt production method of the present invention includes an inlet at one end, an outlet at the other end, and the inlet is positioned above the outlet in the vertical direction. The raw material supply step of supplying the glass raw material into the raw material processing member from the inlet of the raw material processing member having a shape selected from a cylindrical shape and a bowl shape, and the glass supplied into the raw material processing member Glass raw material through at least a heating / melting step of heating and melting while moving the raw material from the inlet to the outlet and a solidifying step of cooling and solidifying the melt of the glass raw material flowing down from the outlet When the crude melt is produced and the glass raw material is moved from the inlet to the outlet side in the raw material processing member, the glass raw material is temporarily retained in the raw material processing member.

本発明のガラス原料粗溶解物製造方法の一実施態様は、ガラス原料が、Ti化合物、Nb化合物、W化合物、Bi化合物およびLa化合物から選択される少なくともいずれか1種の金属を含むものであることが好ましい。   In one embodiment of the method for producing a crude raw material for glass raw material of the present invention, the glass raw material contains at least one metal selected from a Ti compound, an Nb compound, a W compound, a Bi compound, and an La compound. preferable.

本発明のガラス原料粗溶解物製造方法の他の実施態様は、原料処理部材が筒状部材からなり、筒状部材内に、ガラス原料を一時的に滞留させるための滞留部形成部材が、筒状部材の中心軸に対して、略点対称を成すように配置され、かつ、加熱・溶解工程において、筒状部材を、その中心軸を回転軸として回転させることが好ましい。   In another embodiment of the method for producing a glass raw material crude melt according to the present invention, the raw material processing member is formed of a cylindrical member, and the retention portion forming member for temporarily retaining the glass raw material in the cylindrical member is a cylinder. Preferably, the cylindrical member is arranged so as to be substantially point-symmetric with respect to the central axis of the cylindrical member, and the cylindrical member is rotated about the central axis as a rotation axis in the heating / melting step.

本発明の光学ガラスの製造方法は、本発明のガラス原料粗溶解物の製造方法によりガラス原料粗溶解物を作製し、このガラス原料粗溶解物を、貴金属または貴金属合金製の容器にて本溶解する本溶解工程を少なくとも経て、光学ガラスを製造することを特徴とする。   The method for producing an optical glass of the present invention is to prepare a glass raw material crude melt by the method for producing a glass raw material crude melt of the present invention, and this glass raw material crude melt is melted in a noble metal or noble metal alloy container. The optical glass is manufactured through at least the main melting step.

本発明によれば、ガラス原料粗溶解物を用いて製造される光学ガラスの着色を抑制できるガラス原料粗溶解物の製造方法およびこれを用いた光学ガラスの製造方法を提供することができる。   ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the glass raw material rough melt which can suppress the coloring of the optical glass manufactured using a glass raw material rough melt, and the manufacturing method of optical glass using the same can be provided.

本実施形態のガラス原料粗溶解物の製造方法に用いられる原料溶解炉の一例を示す模式図である。It is a schematic diagram which shows an example of the raw material melting furnace used for the manufacturing method of the glass raw material coarse melt of this embodiment. 図1に示す原料溶解炉に用いる筒状部材(円筒管)の一例を示す模式図である。ここで、図2(A)は図1に示す円筒管を、その中心軸を含む平面で切断した場合の端面図の一例を示し、図2(B)は、図2(A)に示す円筒管を流出口側から見た平面図の一例を示すものである。It is a schematic diagram which shows an example of the cylindrical member (cylindrical tube) used for the raw material melting furnace shown in FIG. Here, FIG. 2 (A) shows an example of an end view when the cylindrical tube shown in FIG. 1 is cut along a plane including its central axis, and FIG. 2 (B) shows the cylinder shown in FIG. 2 (A). An example of the top view which looked at the pipe | tube from the outflow port side is shown. 図1に示す原料溶解炉に用いる筒状部材(円筒管)の他の例を示す平面図である。It is a top view which shows the other example of the cylindrical member (cylindrical pipe) used for the raw material melting furnace shown in FIG. 図1に示す原料溶解炉に用いる筒状部材(円筒管)の他の例を示す平面図であるIt is a top view which shows the other example of the cylindrical member (cylindrical tube) used for the raw material melting furnace shown in FIG. 図2(A)に示す滞留部S内に複数個の阻害部材を密集して配置した例を示す模式図である。FIG. 3 is a schematic diagram illustrating an example in which a plurality of inhibitory members are densely arranged in a staying portion S illustrated in FIG. 図1に示す原料溶解炉に用いる樋状部材(半円筒管)の一例を示す平面図である。It is a top view which shows an example of the bowl-shaped member (semi-cylindrical tube) used for the raw material melting furnace shown in FIG.

本実施形態のガラス原料粗溶解物の製造方法は、一方の端部に投入口を備え、他方の端部に流出口を備え、投入口が流出口よりも鉛直方向に対して(鉛直方向において)上方側に位置するように配置され、かつ、筒状および樋状から選択される形状を有する原料処理部材の投入口から、ガラス原料を原料処理部材内に供給する原料供給工程と、原料処理部材内に供給されたガラス原料を、投入口から、流出口へと移動させつつ加熱・溶解する加熱・溶解工程と、流出口から流れ落ちるガラス原料の融液を、冷却して、固化する固化工程と、を少なくとも経てガラス原料粗溶解物を製造する。ここで、原料処理部材内の投入口から流出口側へガラス原料を移動させる際に、原料処理部材内においてガラス原料を一時的に滞留させる。   The method for producing a glass raw material crude melt according to the present embodiment includes an inlet at one end, an outlet at the other end, and the inlet is perpendicular to the outlet (in the vertical direction). ) A raw material supply step for supplying a glass raw material into the raw material processing member from an inlet of the raw material processing member which is arranged to be positioned on the upper side and has a shape selected from a cylindrical shape and a bowl shape, and a raw material processing A heating / melting process in which the glass raw material supplied into the member is heated and melted while moving from the inlet to the outlet, and a solidification process in which the melt of the glass raw material flowing down from the outlet is cooled and solidified. And at least the glass raw material crude melt is produced. Here, when the glass raw material is moved from the inlet in the raw material processing member to the outlet side, the glass raw material is temporarily retained in the raw material processing member.

なお、本願明細書において「ガラス原料」とは、未ガラス化原料、すなわちバッチ原料を意味する。また、原料処理部材は、筒状の形状を有する部材(筒状部材)、および、樋状の形状を有する部材(樋状部材)のいずれかから選択される。それゆえ、筒状部材では、一方の端部に設けられた開口部が投入口となり、他方の端部に設けられた開口部が流出口となる。また、桶状部材としては、筒状部材の外周面の一部または全部が、この筒状部材の長手方向に沿って開口している部材も含まれる。樋状部材は、長手方向に沿って開口している開口部分が、鉛直方向に対して上方側を向くように配置されることが特に好ましい。この場合、樋状部材内を投入口から流出口側へと移動するガラス原料が、樋状部材からこぼれ落ちるのを抑制することが極めて容易になる。   In the present specification, “glass raw material” means an unvitrified raw material, that is, a batch raw material. Moreover, the raw material processing member is selected from any of a member having a cylindrical shape (cylindrical member) and a member having a bowl-like shape (ridge-like member). Therefore, in the cylindrical member, an opening provided at one end serves as an inlet, and an opening provided at the other end serves as an outlet. Moreover, as a hook-shaped member, the member by which a part or all of the outer peripheral surface of a cylindrical member is opened along the longitudinal direction of this cylindrical member is also contained. It is particularly preferable that the hook-shaped member is disposed so that the opening portion that opens along the longitudinal direction faces upward with respect to the vertical direction. In this case, it becomes very easy to suppress the glass raw material moving from the inlet to the outlet side in the bowl-shaped member from spilling from the bowl-shaped member.

したがって、本実施形態のガラス原料粗溶解物の製造方法では、従来と比べて、原料処理部材内にてより長時間に亘ってガラス原料を加熱・溶解することができる。このため、粗溶解物のガラス化度合をより高めることができ、本溶解時の白金坩堝の侵蝕に起因する光学ガラスの着色を抑制できる。また、本実施形態のガラス原料粗溶解物の製造方法では、ガラス原料の加熱・溶解に際して、粗溶解物のガラス化度合をより高めるために、加熱時間をより長くすることができるため、加熱温度をより高くしなくてもよい。言い換えれば、従来のガラス原料粗溶解物の製造方法で作製された粗溶解物と同程度のガラス化度合を得るために、ガラス原料を、より低温で、より長時間、加熱・溶解することができる。このため、ガラス原料中に、高温下での還元反応により光学ガラスを着色させ易い金属が含まれていても、本実施形態のガラス原料粗溶解物の製造方法では、これら金属の還元反応に起因する光学ガラスの着色も容易に抑制できる。   Therefore, in the manufacturing method of the glass raw material coarse melt of this embodiment, compared with the past, a glass raw material can be heated and melt | dissolved over a longer time within a raw material processing member. For this reason, the vitrification degree of the coarsely dissolved material can be further increased, and coloring of the optical glass due to the erosion of the platinum crucible during the main melting can be suppressed. Further, in the method for producing a glass material crude melt according to the present embodiment, the heating time can be further increased in order to increase the vitrification degree of the crude melt when heating and melting the glass material. Need not be higher. In other words, in order to obtain the same degree of vitrification as a crude melt produced by the conventional method for producing a raw material crude melt, it is possible to heat and melt the glass raw material at a lower temperature for a longer time. it can. For this reason, even if the glass raw material contains a metal that easily colors the optical glass by a reduction reaction at a high temperature, the method for producing a crude raw material for glass raw material according to the present embodiment results from the reduction reaction of these metals. The coloring of the optical glass can be easily suppressed.

高温下での還元反応により光学ガラスを着色させ易い金属成分としては、Ti、Nb、W、Bi等が挙げられ、これらの中でも、光学ガラスに対する着色性の高さ、または、多くの光学ガラスにおいて用いられる汎用性という観点から、前記金属成分として、TiおよびNbが挙げられる。このような観点からは、本実施形態のガラス原料溶解物の製造方法に用いられるガラス原料は、Ti化合物、Nb化合物、W化合物およびBi化合物から選択される少なくともいずれか1種の金属を含むことが特に好ましい。さらにLa化合物などの希土類化合物は溶解しにくい成分であることから溶解温度を高くしなければならない。溶解温度が高くなると侵蝕性が高くなったり、上記着色しやすい金属成分が還元して、ガラスが着色しやすくなる。このため、本実施形態のガラス原料溶解物の製造方法は、希土類化合物、特にLa化合物を含むガラス原料溶解物の製造に好適である。以上より、本実施形態のガラス原料溶解物の製造方法に用いられるガラス原料は、Ti化合物、Nb化合物、W化合物、Bi化合物およびLa化合物から選択される少なくともいずれか1種の金属を含むことが特に好ましい。   Examples of the metal component that easily colors the optical glass by a reduction reaction at high temperature include Ti, Nb, W, Bi, etc. Among these, high colorability for optical glass, or in many optical glasses From the viewpoint of versatility used, examples of the metal component include Ti and Nb. From such a viewpoint, the glass raw material used in the method for producing a glass raw material melt according to the present embodiment includes at least one metal selected from a Ti compound, an Nb compound, a W compound, and a Bi compound. Is particularly preferred. Furthermore, since rare earth compounds such as La compounds are difficult to dissolve, the melting temperature must be increased. When the melting temperature is increased, the erosion property is increased, or the metal components that are easily colored are reduced, and the glass is easily colored. For this reason, the manufacturing method of the glass raw material melt | dissolution of this embodiment is suitable for manufacture of the glass raw material melt | dissolution containing a rare earth compound, especially La compound. As mentioned above, the glass raw material used for the manufacturing method of the glass raw material melt | dissolution of this embodiment contains at least any 1 type of metal selected from Ti compound, Nb compound, W compound, Bi compound, and La compound. Particularly preferred.

なお、本願明細書において、「光学ガラスの着色」とは、光学ガラスに要求される光学特性上、本来高い透過率を有するべき所定の波長域での望ましく無い透過率の低下が起こることを意味し、狭義には可視域の波長範囲での望ましく無い透過率の低下を意味するが、広義には、近赤外域の波長範囲または近紫外域の波長範囲での望ましく無い透過率の低下を意味する場合も含む。   In the specification of the present application, “coloring of optical glass” means that, due to optical characteristics required for optical glass, an undesired decrease in transmittance occurs in a predetermined wavelength region that should originally have high transmittance. In the narrow sense, it means an undesired decrease in transmittance in the visible wavelength range, but in a broad sense, it means an undesired decrease in transmittance in the near-infrared wavelength range or near-ultraviolet wavelength range. This includes cases where

原料処理部材の投入口から流出口へとガラス原料を移動させる際には、原料処理部材内においてガラス原料を一時的に滞留させる。ここで、原料処理部材内においてガラス原料を一時的に滞留させる方法(滞留方法)としては、特に限定されないが、たとえば、(1)原料処理部材内に、ガラス原料の、原料処理部材の長手方向に対するスムーズな移動を一時的に妨げる堰または障害物を配置する方法、および、(2)原料処理部材の内周面に、ガラス原料の溜まり場となる凹部を設ける方法、が挙げられる。ここで、堰としては、内周面に対して突出するように設けられた凸部、投入口側の内径に対して流出口側の内径が小さくなるように内周面に設けられた段差、融液状のガラス原料が通過可能な貫通穴を設けた仕切り板などが一例として挙げられる。   When the glass raw material is moved from the inlet of the raw material processing member to the outlet, the glass raw material is temporarily retained in the raw material processing member. Here, the method of temporarily retaining the glass raw material in the raw material processing member (retention method) is not particularly limited. For example, (1) the longitudinal direction of the raw material processing member of the glass raw material in the raw material processing member And a method of disposing a weir or an obstacle that temporarily hinders smooth movement of the material, and (2) a method of providing a concave portion serving as a reservoir for glass raw material on the inner peripheral surface of the raw material processing member. Here, as the weir, a convex portion provided so as to protrude with respect to the inner peripheral surface, a step provided on the inner peripheral surface so that the inner diameter on the outlet side becomes smaller than the inner diameter on the inlet side, An example is a partition plate provided with a through-hole through which a molten glass material can pass.

ここで、上記(1)の滞留方法では、原料処理部材内を移動するガラス原料が、堰または障害物によって、押し留められたり、移動速度が大幅に低下したりする。このため、ガラス原料が原料処理部材内に一時的に滞留する。また、上記(2)の滞留方法では、原料処理部材内を移動するガラス原料が、凹部に入り込み、この部分で一時的に滞留した後、凹部を溢れ出たガラス原料が再び流出口側へと移動することになる。   Here, in the staying method (1), the glass raw material moving in the raw material processing member is held down by a weir or an obstacle, or the moving speed is greatly reduced. For this reason, the glass raw material is temporarily retained in the raw material processing member. Further, in the retention method (2), the glass material moving in the raw material processing member enters the concave portion, and after temporarily retaining in this portion, the glass raw material overflowing the concave portion returns to the outlet side again. Will move.

次に、本実施形態のガラス原料粗溶解物の製造方法および光学ガラスの製造方法について、各工程別により詳細に説明する。   Next, the manufacturing method of the glass raw material crude melt and the manufacturing method of the optical glass according to the present embodiment will be described in detail for each step.

まず、原料供給工程では、原料処理部材の投入口からガラス原料を投入する。ここで、ガラス原料としては、リン酸を含むガラス原料であれば特に限定されない。なお、リン酸以外のその他のガラス原料を構成する成分としては、Si、Ge、B、Al、Zr、Li、Na、K、Mg、Ca、Sr、Ba、Ti、Nb、Zn、La、Gd、Y、Yb、W、Bi、In、Sc、Te、Ga、Sb等の光学ガラスの製造に用いられる各種元素を含む酸化物、炭酸塩、水酸化物など、公知のガラス製造用の原料が利用できる。また、本溶解時の清澄性を確保するため、ガラス原料を構成する各成分の少なくとも1種類は、炭酸塩等のように、加熱によりガスが発生する成分が選択される。また、ガラス原料は、通常、作製する光学ガラスの組成に応じて各種の成分を適宜混合した粉末状のものが用いられる。   First, in the raw material supply step, the glass raw material is introduced from the inlet of the raw material processing member. Here, the glass raw material is not particularly limited as long as it is a glass raw material containing phosphoric acid. In addition, as components constituting other glass raw materials other than phosphoric acid, Si, Ge, B, Al, Zr, Li, Na, K, Mg, Ca, Sr, Ba, Ti, Nb, Zn, La, Gd There are known raw materials for glass production such as oxides, carbonates and hydroxides containing various elements used in the production of optical glass such as Y, Yb, W, Bi, In, Sc, Te, Ga and Sb. Available. Moreover, in order to ensure the clarity at the time of this melt | dissolution, the component which generate | occur | produces gas by heating like the carbonate etc. is selected as at least 1 type of each component which comprises a glass raw material. In addition, the glass raw material is usually a powdery material in which various components are appropriately mixed according to the composition of the optical glass to be produced.

ガラス原料を原料処理部材の投入口から原料処理部材内に投入する場合は、ガラス原料を連続的に投入してもよく、一定の時間間隔を置いて逐次投入してもよい。また、単位時間当たりのガラス原料の投入量も、原料処理部材のサイズ・構造や、ガラス原料の加熱・溶解条件等に応じて適宜選択することができる。   When the glass raw material is introduced into the raw material processing member from the inlet of the raw material processing member, the glass raw material may be continuously supplied or may be sequentially added at a constant time interval. Also, the amount of glass raw material input per unit time can be appropriately selected according to the size / structure of the raw material processing member, the heating / melting conditions of the glass raw material, and the like.

加熱・溶解工程では、原料処理部材内に投入されたガラス原料を加熱・溶解する。ここで、原料処理部材、ならびに、ガラス原料を原料処理部材内に一時的に滞留させるために必要に応じて原料処理部材内に設けられる堰および障害物を構成する材料としては、ガラス原料に対する耐蝕性および耐熱性を有する耐蝕・耐熱材料が用いられる。このような耐蝕・耐熱材料としては通常、石英ガラスが用いられる。また、原料処理部材ならびに必要に応じて用いられる堰および障害物は、加熱・溶解工程においてガラス原料と接触する部分が耐蝕・耐熱材料から構成されていればよいが、通常は、これら部材全体が耐蝕・耐熱材料から構成される。ここで、原料処理部材が筒状部材からなる場合、加熱・溶解工程の実施に際して、筒状部材は、その中心軸を回転軸として適宜回転させることが好ましい。これにより、筒状部材の内周面の局所的な侵蝕を防ぐことができる。   In the heating / melting step, the glass raw material charged into the raw material processing member is heated / melted. Here, as the material constituting the weir and the obstacle provided in the raw material processing member as necessary in order to temporarily retain the raw material processing member and the glass raw material in the raw material processing member, corrosion resistance to the glass raw material is included. Corrosion and heat resistant materials having heat resistance and heat resistance are used. As such a corrosion-resistant and heat-resistant material, quartz glass is usually used. In addition, the raw material processing member and the weirs and obstacles used as necessary may be made of a corrosion-resistant and heat-resistant material in the portion that contacts the glass raw material in the heating / melting step. Consists of corrosion and heat resistant materials. Here, in the case where the raw material processing member is formed of a cylindrical member, it is preferable that the cylindrical member is appropriately rotated with the central axis as a rotation axis when the heating / dissolution process is performed. Thereby, local erosion of the inner peripheral surface of the cylindrical member can be prevented.

原料処理部材内のガラス原料を加熱する装置としては特に限定されず、抵抗発熱体、重油やガスなどの燃焼加熱等の公知の加熱装置を用いることができ、たとえば、棒状のSiCヒータなどを原料処理部材の周囲に配置することができる。ここで、ガラス原料の加熱温度としては、使用するガラス原料の成分等に応じて適宜選択することができるが、通常は、作製される光学ガラスの液相温度を基準として、流出口近傍の測定温度で、液相温度−100度〜液相温度+500度の範囲内で選択することが好ましく、液相温度−50度〜液相温度+300度の範囲内で選択することがより好ましい。また、投入口は、流出口よりも鉛直方向に対して上方側に位置するように配置されていれば、原料処理部材の中心軸の水平方向に対する傾斜角は特に限定されないが、通常は、1°〜30°の範囲内で設定することが好ましい。また、原料処理部材内に投入された固体状態のガラス原料は、通常、流出口近傍に到達した時点で、ほぼ全量が溶解して融液状となるように、加熱温度や傾斜角等の加熱・溶解条件を設定することが好ましい。   The apparatus for heating the glass raw material in the raw material processing member is not particularly limited, and a known heating apparatus such as a resistance heating element, combustion heating such as heavy oil or gas can be used. For example, a rod-shaped SiC heater or the like is used as a raw material. It can arrange | position around a process member. Here, the heating temperature of the glass raw material can be appropriately selected according to the components of the glass raw material to be used, etc., but usually the measurement in the vicinity of the outlet is based on the liquidus temperature of the produced optical glass. The temperature is preferably selected within the range of liquid phase temperature −100 ° C. to liquid phase temperature + 500 ° C., more preferably selected within the range of liquid phase temperature −50 ° C. to liquid phase temperature + 300 ° C. In addition, the inclination angle of the central axis of the raw material processing member with respect to the horizontal direction is not particularly limited as long as the input port is disposed so as to be positioned above the outflow port with respect to the vertical direction. It is preferable to set within the range of from -30 °. In addition, the solid glass raw material charged into the raw material processing member is usually heated and heated at a heating temperature, an inclination angle, etc. so that almost all of the glass raw material is melted into a molten liquid when it reaches the vicinity of the outlet. It is preferable to set dissolution conditions.

固化工程では、流出口から流れ落ちる融液状のガラス原料を、冷却して、固化する。これによりガラス原料粗溶解物を得る。融液状のガラス原料の冷却方法としては特に限定されないが、通常は、水中に、融液状のガラス原料を投入して急冷する。この場合、粒子状のガラス原料粗溶解物が得られる。なお、水冷した場合は、水中からガラス原料粗溶解物を取り出した後、乾燥処理を行う。   In the solidification step, the melted glass material flowing down from the outlet is cooled and solidified. Thereby, a glass raw material crude melt is obtained. The method for cooling the molten glass raw material is not particularly limited. Usually, the molten glass raw material is poured into water and rapidly cooled. In this case, a granular glass raw material crude melt is obtained. In addition, when it cools with water, after taking out a glass raw material coarse melt from water, a drying process is performed.

続いて、本溶解工程を実施するために、ガラス原料粗溶解物を、白金、金、白金合金、金合金などの貴金属または貴金属合金製の容器、例えば、坩堝、樋状あるいはパイプ状の容器に投入して本溶解する。好ましくは白金または白金合金製の坩堝中に投入して本溶解する。その後は、必要に応じて、徐冷、プレス成形、研磨等の後工程を適宜実施することで光学ガラスを得る。なお、光学ガラスは、レンズなどの完成品であってもよく、レンズ等の完成品を製造するために用いるプリフォーム等の半製品であってもよい。   Subsequently, in order to carry out this melting step, the glass raw material crude melt is put into a container made of noble metal or noble metal alloy such as platinum, gold, platinum alloy, gold alloy, such as a crucible, bowl-shaped or pipe-shaped container. Add to the main melt. Preferably, it is put into a crucible made of platinum or a platinum alloy and completely melted. Thereafter, optical glass is obtained by appropriately performing post-processes such as slow cooling, press molding, and polishing as necessary. The optical glass may be a finished product such as a lens or a semi-finished product such as a preform used for manufacturing a finished product such as a lens.

次に、本実施形態のガラス原料粗溶解物の製造方法に用いられる原料溶解炉の具体例について、図面に基づき説明する。   Next, the specific example of the raw material melting furnace used for the manufacturing method of the glass raw material coarse melt of this embodiment is demonstrated based on drawing.

図1は、本実施形態のガラス原料粗溶解物の製造方法に用いられる原料溶解炉の一例を示す模式図であり、具体的には、原料溶解炉の主要部について示した図である。なお、図1およびその他の図において、図中に示す両矢印X方向は水平方向を意味し、両矢印Y方向は鉛直方向を意味し、矢印Y1方向は上方側、矢印Y2方向は下方側を意味する。   FIG. 1 is a schematic view showing an example of a raw material melting furnace used in the method for producing a glass raw material crude melt according to the present embodiment. Specifically, FIG. 1 shows the main part of the raw material melting furnace. In FIG. 1 and other figures, the double arrow X direction in the figure means the horizontal direction, the double arrow Y direction means the vertical direction, the arrow Y1 direction is the upper side, and the arrow Y2 direction is the lower side. means.

図1に示す原料溶解炉10は、長手方向の内径および外径が一定である1本の円筒管(筒状部材)20と、円筒管20の周囲に配置された棒状の抵抗発熱体30と、を有している。なお、図中、円筒管20および抵抗発熱体30の一部または全体を適宜囲うように配置される断熱性の壁、原料溶解炉10内や、円筒管20近傍の温度をモニターするための熱電対等の温度センサー、その他の原料溶解炉10を構成する部材については記載を省略してある。また、円筒管20内の具体的な構造についても記載を省略してある。   A raw material melting furnace 10 shown in FIG. 1 includes a cylindrical tube (tubular member) 20 having a constant inner diameter and outer diameter in the longitudinal direction, and a rod-shaped resistance heating element 30 disposed around the cylindrical tube 20. ,have. In the drawing, a heat insulating wall disposed so as to surround part or all of the cylindrical tube 20 and the resistance heating element 30, a thermoelectric for monitoring the temperature in the raw material melting furnace 10 and the vicinity of the cylindrical tube 20. The description of the temperature sensor and the other members constituting the raw material melting furnace 10 are omitted. Also, the description of the specific structure inside the cylindrical tube 20 is omitted.

ここで、円筒管20は、その中心軸Cが水平方向に対して所定の角度θを成すように傾斜して配置されている。このため、円筒管20の一方の開口部(投入口22)は、他方の開口部(流出口24)よりも上方側に位置する。また、流出口24の下方には水を満たした水槽WBが配置されている。上記傾斜角θの下限は、円筒管20中を、溶解物が流出口24側に向かって流動することが可能な角度のうち、最も小さい角度を選択することが好ましい。また、傾斜角θの上限は、円筒管20中に投入した原料のすべてが未溶解状態まま流出口24側に到達しない角度を上限とすることが好ましい。傾斜角θは例えば0度を超える範囲で適宜選択されるが、通常は、1度〜30度の範囲内とすることが好ましく、1度〜20度の範囲内とすることがより好ましく、1度〜10度の範囲内とすることがさらに好ましい。   Here, the cylindrical tube 20 is disposed so as to be inclined so that the central axis C forms a predetermined angle θ with respect to the horizontal direction. For this reason, one opening part (input port 22) of the cylindrical pipe | tube 20 is located above the other opening part (outflow port 24). A water tank WB filled with water is disposed below the outlet 24. As the lower limit of the inclination angle θ, it is preferable to select the smallest angle among the angles at which the melt can flow toward the outlet 24 in the cylindrical tube 20. In addition, the upper limit of the inclination angle θ is preferably the upper limit of the angle at which all of the raw materials charged into the cylindrical tube 20 do not reach the outlet 24 side in an undissolved state. The inclination angle θ is appropriately selected within a range exceeding, for example, 0 °, but is usually preferably within a range of 1 ° to 30 °, more preferably within a range of 1 ° to 20 °. More preferably, the angle is within the range of 10 to 10 degrees.

ガラス原料粗溶解物の製造に際しては、不図示のガラス原料を投入口22から投入し、ガラス原料を円筒管20内にて加熱・溶解する。そして、融液状のガラス原料が流出口24から、水槽WBに満たした水中に流れ落ちる。この際、融液状のガラス原料が、水中にて、急冷・固化し、粒子状のガラス原料粗溶解物を得る。   In the production of the coarsely melted glass raw material, a glass raw material (not shown) is introduced from the inlet 22, and the glass raw material is heated and melted in the cylindrical tube 20. Then, the molten glass material flows down from the outlet 24 into the water filled in the water tank WB. At this time, the melted glass raw material is rapidly cooled and solidified in water to obtain a granular glass raw material crude melt.

なお、筒状部材20内の具体的構造としては、ガラス原料を一時的に滞留させることができるものであれば特に限定されないが、筒状部材20内にガラス原料を一時的に滞留させるための滞留部形成部材が、筒状部材20の中心軸Cに対して、略点対称を成すように配置されていることが好ましい。そして、この際、加熱・溶解工程において、筒状部材20を、その中心軸を回転軸として回転させることが好ましい。この場合、筒状部材20の回転は、連続的に実施してもよく、断続的に実施してもよい。これにより、筒状部材20内の一部分のみが、ガラス原料により著しく侵蝕されるのを防ぐことができる。これに加えて、ガラス原料を一時的に滞留させる機能を筒状部材20に付与する上で、市販の単純な形状の円筒管と、所定の形状に加工した滞留部形成部材とを用いて組み立を行うことができるので、組立作業が非常に容易である。また、滞留部形成部材の形状およびサイズ、ならびに、筒状部材20内の配置位置を適宜選択することにより、筒状部材20内におけるガラス原料の滞留の度合を容易に制御することができる。さらに、ガラス原料の加熱・溶解処理の経時的なばらつきを抑制することもできる。以下に、滞留部形成部材を筒状部材20の中心軸Cに対して点対称に配置した原料溶解炉10の具体例を図面を用いて説明する。   The specific structure in the cylindrical member 20 is not particularly limited as long as the glass raw material can be temporarily retained, but for temporarily retaining the glass raw material in the cylindrical member 20. It is preferable that the staying portion forming member is arranged so as to be substantially point-symmetric with respect to the central axis C of the cylindrical member 20. At this time, in the heating / melting step, it is preferable that the cylindrical member 20 is rotated with its central axis as the rotation axis. In this case, the rotation of the tubular member 20 may be performed continuously or intermittently. Thereby, only a part in the cylindrical member 20 can be prevented from being significantly eroded by the glass raw material. In addition to this, in order to provide the cylindrical member 20 with a function of temporarily retaining the glass raw material, the cylindrical member 20 is assembled by using a commercially available simple cylindrical tube and a retention portion forming member processed into a predetermined shape. Therefore, the assembly work is very easy. In addition, by appropriately selecting the shape and size of the staying portion forming member and the arrangement position in the tubular member 20, the degree of staying of the glass raw material in the tubular member 20 can be easily controlled. Furthermore, the time-dependent dispersion | variation in the heating / melting | dissolving process of a glass raw material can also be suppressed. Below, the specific example of the raw material melting furnace 10 which has the retention part formation member arrange | positioned point-symmetrically with respect to the central axis C of the cylindrical member 20 is demonstrated using drawing.

図2は、図1に示す原料溶解炉に用いる筒状部材(円筒管)の一例を示す模式図である。ここで、図2(A)は図1に示す円筒管を、その中心軸を含む平面で切断した場合の端面図の一例を示し、図2(B)は、図2(A)に示す円筒管を流出口側から見た平面図の一例を示すものである。   FIG. 2 is a schematic diagram showing an example of a cylindrical member (cylindrical tube) used in the raw material melting furnace shown in FIG. Here, FIG. 2 (A) shows an example of an end view when the cylindrical tube shown in FIG. 1 is cut along a plane including its central axis, and FIG. 2 (B) shows the cylinder shown in FIG. 2 (A). An example of the top view which looked at the pipe | tube from the outflow port side is shown.

図2に示す円筒管20A(20)の内周には、同一の形状・サイズからなる8個のブロック状の滞留部形成部材40A(40)が固定して配置されている。図2に示す滞留部形成部材40Aは、ガラス原料Mの、円筒管20Aの長手方向に対するスムーズな移動を一時的に妨げる堰としての機能を有し、円筒管20Aの内径と同程度の外径を有する円筒管を輪切りにして得られたリング状部材を8等分するように切断する工程を経て作製された部材である。なお、切断後、滞留部形成部材40Aの形状・サイズを調整するために、必要に応じて切断面が研磨または研削されてもよい。   On the inner periphery of the cylindrical tube 20A (20) shown in FIG. 2, eight block-like staying portion forming members 40A (40) having the same shape and size are fixedly arranged. The retention part forming member 40A shown in FIG. 2 has a function as a weir that temporarily prevents smooth movement of the glass raw material M in the longitudinal direction of the cylindrical tube 20A, and has an outer diameter that is approximately the same as the inner diameter of the cylindrical tube 20A. A ring-shaped member obtained by cutting a cylindrical tube having a ring is cut into eight equal parts and is produced through a step. In addition, after cutting, in order to adjust the shape and size of the staying portion forming member 40A, the cut surface may be polished or ground as necessary.

ここで8個の滞留部形成部材40Aは、中心軸Cに対して、円筒管20Aの中央部よりやや流出口24側の位置に、円筒管20Aの内周面26に密着するように、円筒管20Aの内周方向に沿って配置されている。なお、以下の説明においては、特に説明の無い限り、中心軸Cに対する滞留部形成部材40の配置位置は、図2(A)に例示される位置に配置されるものとする。   Here, the eight staying portion forming members 40A are cylindrical so as to be in close contact with the inner peripheral surface 26 of the cylindrical tube 20A at a position slightly closer to the outlet 24 side than the central portion of the cylindrical tube 20A with respect to the central axis C. It arrange | positions along the inner peripheral direction of the pipe | tube 20A. In the following description, unless otherwise specified, the arrangement position of the staying portion forming member 40 with respect to the central axis C is assumed to be arranged at the position illustrated in FIG.

また、図2に示す例では、内周方向において互いに隣接する2つの滞留部形成部材40Aの間には、隙間W1が形成されている。この隙間長さ(周方向の長さ)は、バッチ原料の塊が通過できないような長さ、例えば0mm〜5mmの範囲内とすることが好ましく、0mm〜3mmの範囲内とすることがより好ましく、0mm〜1mmの範囲内とすることがさらに好ましい。隙間長さを上記範囲内とすることにより、固体状態のガラス原料M(S)が、滞留部Sに流れ込んだ場合、ガラス原料M(S)を滞留部Sに確実に留めることができる。これに加えて、ガラス原料M(S)が溶解して液状となったガラス原料M(L)を滞留部Sに一時的に滞留させることができると共に、滞留部Sから、流出口24側へと徐々に流出させることができる。この場合、隙間長さや、周方向に設けられる隙間W1の個数を適宜選択することにより、滞留部Sから流出口24側へと流出するガラス原料M(L)の単位時間当たりの流出量を容易に制御できる。   In the example shown in FIG. 2, a gap W1 is formed between two staying portion forming members 40A adjacent to each other in the inner circumferential direction. The gap length (the length in the circumferential direction) is preferably such that the batch raw material lump cannot pass through, for example, in the range of 0 mm to 5 mm, and more preferably in the range of 0 mm to 3 mm. More preferably, it is in the range of 0 mm to 1 mm. By setting the gap length within the above range, when the glass raw material M (S) in the solid state flows into the staying part S, the glass raw material M (S) can be reliably retained in the staying part S. In addition to this, the glass raw material M (L) in which the glass raw material M (S) has been dissolved can be temporarily retained in the retention portion S, and from the retention portion S to the outlet 24 side. And can be gradually drained. In this case, by appropriately selecting the gap length and the number of gaps W1 provided in the circumferential direction, the outflow amount per unit time of the glass raw material M (L) flowing out from the staying portion S toward the outflow port 24 can be easily obtained. Can be controlled.

なお、滞留部形成部材40を、円筒管20の内周に固定して配置する方法としては、公知の固定方法が適宜選択できる。たとえば、図2に示す例では、滞留部形成部材40Aを、内周面26に対して接着剤で接着する化学的固定方法や、滞留部形成部材40Aと内周面26とを溶接または融着する物理的固定方法が利用できる。ここで、接着剤は、この接着剤により形成された接着層が、ガラス原料の加熱温度において耐熱性を備えると共に、ガラス原料と反応またはガラス原料が溶解した融液により侵食され難いものであることが好ましい。また、固定方法としては、各種の機械的固定方法も利用できる。このような機械的固定方法としては、たとえば、内周面26に滞留部形成部材40Aを係止するための凸部を設け、この凸部を利用して滞留部形成部材40Aを固定することもできる。この場合、中心軸Cに対して凸部の投入口22が設けられた側に滞留部形成部材40Aを配置することで、滞留部形成部材40Aが、その自重により流出口24側に滑り落ちるのを防止できるように固定することができる。または、内周面26と、滞留部形成部材40Aの内周面26と対向する面にそれぞれ穴を設け、これらの穴にピンを差し込むことで内周面26に対して滞留部形成部材40Aを固定することができる。   In addition, as a method of fixing and arranging the stay part forming member 40 on the inner periphery of the cylindrical tube 20, a known fixing method can be appropriately selected. For example, in the example shown in FIG. 2, a chemical fixing method in which the staying portion forming member 40A is bonded to the inner peripheral surface 26 with an adhesive, or the staying portion forming member 40A and the inner peripheral surface 26 are welded or fused. Physical fixing methods can be used. Here, the adhesive is such that the adhesive layer formed by this adhesive has heat resistance at the heating temperature of the glass raw material and is not easily eroded by the melt with the glass raw material reacting with or dissolving the glass raw material. Is preferred. Various mechanical fixing methods can be used as the fixing method. As such a mechanical fixing method, for example, a protrusion for locking the staying portion forming member 40A is provided on the inner peripheral surface 26, and the staying portion forming member 40A is fixed using this protrusion. it can. In this case, by arranging the staying part forming member 40A on the side where the convex inlet 22 is provided with respect to the central axis C, the staying part forming member 40A slides down to the outlet 24 side due to its own weight. It can be fixed so that it can be prevented. Alternatively, holes are provided in the inner peripheral surface 26 and the surface facing the inner peripheral surface 26 of the staying portion forming member 40A, and the staying portion forming member 40A is attached to the inner peripheral surface 26 by inserting pins into these holes. Can be fixed.

次に、図2に示す円筒管20Aの投入口22からガラス原料Mを投入した場合のガラス原料Mの加熱・溶解のプロセスの一例について説明する。まず、固体状態のガラス原料M(S)を、円筒管20Aの投入口22から投入することで、投入口22近傍の内周面26上に配置する。この際、ガラス原料M(S)は加熱・溶解しながら、流出口24側へと移動する。そして、融液状態となったガラス原料M(L)は、内周面26に沿ってそのまま流出口24側へとスムーズに流れ落ちずに、一旦、滞留部形成部材40Aにより堰止められる。そして、ガラス原料M(L)は、滞留部形成部材40Aの投入口22側の近傍の領域(滞留部S)のうち、鉛直方向の最下方側近傍の領域S0に、一時的に滞留する。この滞留部Sでは、円筒管20Aの長手方向に対して、ガラス原料M(L)の水深が局所的に深くなる。ここで、滞留部Sに滞留するガラス原料M(L)は、たとえば、内周方向に互いに隣接する滞留部形成部材40Aの間の隙間W1を通過したり、および/または、融液面の上昇により滞留部形成部材40Aの内周面40AI(中心軸C側の面)を乗り越えたりすることで、徐々に流出口24側へと流れ落ちる。   Next, an example of the heating and melting process of the glass raw material M when the glass raw material M is supplied from the inlet 22 of the cylindrical tube 20A shown in FIG. 2 will be described. First, the glass raw material M (S) in a solid state is placed on the inner peripheral surface 26 in the vicinity of the charging port 22 by charging from the charging port 22 of the cylindrical tube 20A. At this time, the glass raw material M (S) moves to the outlet 24 side while being heated and melted. Then, the glass raw material M (L) in the melt state is temporarily blocked by the staying portion forming member 40 </ b> A without smoothly flowing down to the outlet 24 side as it is along the inner peripheral surface 26. Then, the glass raw material M (L) temporarily stays in the region S0 in the vicinity of the lowermost side in the vertical direction among the regions in the vicinity of the charging port 22 side (the staying portion S) of the staying portion forming member 40A. In this stay part S, the water depth of the glass raw material M (L) becomes locally deep with respect to the longitudinal direction of the cylindrical tube 20A. Here, the glass raw material M (L) staying in the staying part S passes, for example, the gap W1 between the staying part forming members 40A adjacent to each other in the inner circumferential direction and / or the rise of the melt surface. As a result of overcoming the inner peripheral surface 40AI (surface on the central axis C side) of the staying portion forming member 40A, the flow gradually falls to the outlet 24 side.

なお、ガラス原料Mは、円筒管20内への投入前の状態において、通常は粉末状の固体材料が用いられるが、粗い粒子状の固体材料、インゴット状の固体材料、または、これら材料を2種類以上混合した材料等を適宜選択して用いることもできる。また、滞留部Sに滞留するガラス原料Mは、通常は液体状であることが好ましいが、これに限定されるものではなく、たとえば、固体と液体とが混合した状態であってもよい。   As the glass raw material M, a powdery solid material is usually used in a state before being charged into the cylindrical tube 20, but a coarse particle solid material, an ingot-shaped solid material, or 2 of these materials are used. It is also possible to appropriately select and use a material mixed with two or more types. Moreover, although it is preferable that the glass raw material M which retains in the retention part S is normally a liquid form, it is not limited to this, For example, the state which the solid and the liquid mixed may be sufficient.

また、固体状態のガラス原料M(S)の円筒管20内への投入に際しては、円筒管20内に新たに投入されるガラス原料Mが、滞留部S内に滞留する液状のガラス原料M(L)の液面に覆いかぶさらないように投入されることが好ましい。新たに投入されるガラス原料M(L)が、滞留部S内に滞留する液状のガラス原料M(L)の液面を覆うように投入された場合、滞留部S内に滞留する液状のガラス原料M(L)が、滞留部形成部材40Aの上面側を乗り越えて、一時に多量に流出口24側へと流れ出すためである。この場合、ガラス原料Mを加熱・溶解するプロセスにばらつきが生じ易くなる。これに加えて、流出口24から流れ落ちる融液を水槽WB中に投入してガラス原料粗溶解物を得る場合、粒径が大きくばらつくことになる。   In addition, when the glass raw material M (S) in the solid state is charged into the cylindrical tube 20, the glass raw material M newly charged into the cylindrical tube 20 is liquid glass raw material M ( It is preferable to add so that it does not cover the liquid surface of L). When the newly introduced glass raw material M (L) is introduced so as to cover the liquid surface of the liquid glass raw material M (L) staying in the staying part S, the liquid glass staying in the staying part S This is because the raw material M (L) flows over the upper surface side of the staying portion forming member 40A and flows out to the outlet 24 side in a large amount at a time. In this case, variations tend to occur in the process of heating and melting the glass raw material M. In addition to this, when the melt flowing down from the outlet 24 is put into the water tank WB to obtain a glass raw material crude melt, the particle size greatly varies.

図3は、図1に示す原料溶解炉に用いる筒状部材(円筒管)の他の例を示す平面図であり、具体的には、図2に例示した円筒管の変形例を示した図である。ここで、図3に示す平面図は、円筒管を流出口側から見た平面図である。   FIG. 3 is a plan view showing another example of the cylindrical member (cylindrical tube) used in the raw material melting furnace shown in FIG. 1, and more specifically, a diagram showing a modification of the cylindrical tube exemplified in FIG. It is. Here, the plan view shown in FIG. 3 is a plan view of the cylindrical tube as seen from the outlet side.

図3に示す円筒管20B(20)の内周には、同一の形状・サイズからなる8個のブロック状の滞留部形成部材40B(40)が固定して配置されている。図3に示す滞留部形成部材40Bは、ガラス原料Mの、円筒管20Bの長手方向に対するスムーズな移動を一時的に妨げる堰としての機能を有し、円筒管20Bの内径と同程度の外径を有する円筒管を輪切りにして得られたリング状部材を8等分するように切断する工程を経て作製された部材である。図3に示す滞留部形成部材40Bは、図2に示す滞留部形成部材40Aと実質的に同様の形状・機能を有する部材である。8個の滞留部形成部材40Bは、円筒管20Bの内周面26に密着するように、円筒管20Bの内周方向に沿って配置され、かつ、内周方向において互いに隣接する2つの滞留部形成部材40Bの間には、隙間W2が形成されている。   On the inner periphery of the cylindrical tube 20B (20) shown in FIG. 3, eight block-like staying portion forming members 40B (40) having the same shape and size are fixedly arranged. The retention part forming member 40B shown in FIG. 3 has a function as a dam that temporarily prevents smooth movement of the glass raw material M in the longitudinal direction of the cylindrical tube 20B, and has an outer diameter that is the same as the inner diameter of the cylindrical tube 20B. A ring-shaped member obtained by cutting a cylindrical tube having a ring is cut into eight equal parts and is produced through a step. The staying part forming member 40B shown in FIG. 3 is a member having substantially the same shape and function as the staying part forming member 40A shown in FIG. The eight staying portion forming members 40B are arranged along the inner peripheral direction of the cylindrical tube 20B so as to be in close contact with the inner peripheral surface 26 of the cylindrical tube 20B, and are adjacent to each other in the inner peripheral direction. A gap W2 is formed between the forming members 40B.

また、1つのリングを構成するように円筒管20B内に配置された8個の滞留部形成部材40Bの内周側には、1つのリングを構成するように4個のブロック状部材50が固定して配置される。このブロック状部材50は、1本の円筒管を輪切りにしたリング状部材を4等分し、8個の滞留部形成部材40Bの内周側に配置できるように、適宜研削して形状を整えた部材である。   Further, four block members 50 are fixed so as to constitute one ring on the inner peripheral side of the eight staying portion forming members 40B arranged in the cylindrical tube 20B so as to constitute one ring. Arranged. The block-shaped member 50 is divided into four equal ring-shaped members obtained by slicing one cylindrical tube, and is appropriately ground so as to be arranged on the inner peripheral side of the eight staying portion forming members 40B. It is a member.

図3に示す例では、円筒管20Bの中心軸C方向のガラス原料Mや空気の自由な移動を遮断する1枚の仕切り壁を構成するように、滞留部形成部材40Bおよびブロック状部材50が円筒管20Bの内周側に配置されている。また、滞留部形成部材40Bと、ブロック状部材50との間には、間隙M1が形成されている。そして、この隙間M1は、少なくとも、固体状態のガラス原料M(S)の流動を阻害することができる程度の大きさを有する。   In the example shown in FIG. 3, the retention portion forming member 40 </ b> B and the block-shaped member 50 are configured so as to constitute one partition wall that blocks the free movement of the glass raw material M and air in the direction of the central axis C of the cylindrical tube 20 </ b> B. It arrange | positions at the inner peripheral side of the cylindrical tube 20B. Further, a gap M <b> 1 is formed between the staying part forming member 40 </ b> B and the block-like member 50. And this clearance gap M1 has a magnitude | size which can inhibit the flow of the glass raw material M (S) of a solid state at least.

ここで、単位時間当たりに、円筒管20B内に投入されるガラス原料Mの投入量が少ない場合は、滞留部形成部材40Bのみが、ガラス原料Mを円筒管20B内に一時的に滞留させる機能を発揮する。この点は、図2に示す円筒管20Aを構成する滞留部形成部材40Aも同様である。   Here, when the input amount of the glass raw material M input into the cylindrical tube 20B per unit time is small, only the retention portion forming member 40B temporarily stores the glass raw material M in the cylindrical tube 20B. To demonstrate. This also applies to the staying portion forming member 40A constituting the cylindrical tube 20A shown in FIG.

一方、図2に示す円筒管20Aでは、単位時間当たりの円筒管20A内に投入されるガラス原料Mの投入量が大きい場合には、溶解しきれなかった固体状態のガラス原料M(S)が滞留部形成部材40Aの内周面40AIを乗り越えて、流出口24側へと移動してしまうことになる。これに対して、図3に示す円筒管20Bでは、単位時間当たりの円筒管20B内に投入されるガラス原料Mの投入量が大きい場合でもブロック状部材50もガラス原料Mを円筒管20B内に一時的に滞留させる機能を発揮する。すなわち、ブロック状部材50は、ガラス原料Mの投入量が大きい場合には、ガラス原料Mの、円筒管20Bの長手方向に対するスムーズな移動を一時的に妨げる堰としての機能することができる。   On the other hand, in the cylindrical tube 20A shown in FIG. 2, when the input amount of the glass raw material M introduced into the cylindrical tube 20A per unit time is large, the solid-state glass raw material M (S) that could not be completely dissolved is obtained. It will move over the inner peripheral surface 40AI of the staying part forming member 40A and move toward the outlet 24 side. On the other hand, in the cylindrical tube 20B shown in FIG. 3, even when the input amount of the glass raw material M introduced into the cylindrical tube 20B per unit time is large, the block-shaped member 50 also puts the glass raw material M into the cylindrical tube 20B. Demonstrate temporary retention. That is, when the input amount of the glass raw material M is large, the block-shaped member 50 can function as a weir that temporarily prevents smooth movement of the glass raw material M in the longitudinal direction of the cylindrical tube 20B.

図4は、図1に示す原料溶解炉に用いる筒状部材(円筒管)の他の例を示す平面図である。ここで、図4に示す平面図は、円筒管を流出口側から見た平面図である。   4 is a plan view showing another example of a cylindrical member (cylindrical tube) used in the raw material melting furnace shown in FIG. Here, the plan view shown in FIG. 4 is a plan view of the cylindrical tube as seen from the outlet side.

図4に示す円筒管20C(20)の内周には、同一の形状・サイズからなる4個のブロック状の滞留部形成部材40C(40)が、内周方向に固定して配置されている。図4に示す滞留部形成部材40Cは、円筒管20Cの内径と同程度の外径を有する円筒管を輪切りにして得られたリング状部材を周方向に4等分するように切断する工程を経て作製された部材である。この滞留部形成部材40Cは、滞留部形成部材40Cの作製に用いたリング状部材の内周面であった面(凹面40CD)が、内周面26と対向するように円筒管20Cの内周に配置されている。このため、滞留部形成部材40Cの凹面40CDと、内周面26との間には、液状のガラス原料M(L)が容易に通過可能な間隙G2が形成される。また、内周面26の周方向に互いに隣接する2つの滞留部形成部材40Cの端面40CSと、内周面26との間にも、液状のガラス原料M(L)が容易に通過可能な間隙G3が形成される。この端面40CSは、滞留部形成部材40Cの作製に用いたリング状部材を切断した際に形成された切断面である。   On the inner periphery of the cylindrical tube 20C (20) shown in FIG. 4, four block-shaped staying portion forming members 40C (40) having the same shape and size are fixedly arranged in the inner peripheral direction. . The retaining portion forming member 40C shown in FIG. 4 is a step of cutting a ring-shaped member obtained by cutting a cylindrical tube having an outer diameter similar to the inner diameter of the cylindrical tube 20C into four equal parts in the circumferential direction. It is a member produced through the process. This staying portion forming member 40C has an inner periphery of the cylindrical tube 20C so that a surface (concave surface 40CD) that is the inner peripheral surface of the ring-shaped member used for producing the staying portion forming member 40C faces the inner peripheral surface 26. Is arranged. For this reason, a gap G2 through which the liquid glass raw material M (L) can easily pass is formed between the concave surface 40CD of the staying portion forming member 40C and the inner peripheral surface 26. Further, a gap through which the liquid glass raw material M (L) can easily pass between the end surfaces 40CS of the two staying portion forming members 40C adjacent to each other in the circumferential direction of the inner peripheral surface 26 and the inner peripheral surface 26. G3 is formed. This end surface 40CS is a cut surface formed when the ring-shaped member used for the production of the retention portion forming member 40C is cut.

図4に示す滞留部形成部材40Cは、円筒管20Cの長手方向に対して、固体状態のガラス原料M(S)のスムーズな移動を一時的に妨げる障害物として機能する。   The retention part forming member 40C shown in FIG. 4 functions as an obstacle that temporarily prevents smooth movement of the glass raw material M (S) in the solid state with respect to the longitudinal direction of the cylindrical tube 20C.

図1〜図4に例示した円筒管20、滞留部形成部材40、ブロック状部材50を構成する材料としては、ガラス原料Mに対する耐蝕性と、ガラス原料Mを加熱・溶解する際の温度に耐えうる耐熱性とを有する材料が用いられ、通常は、石英ガラスが用いられる。しかしながら、ガラス原料Mを加熱・溶解する処理を長時間に亘って実施した場合、円筒管20、滞留部形成部材40、ブロック状部材50を構成する材料は徐々に侵蝕される。このため、図2および図3に例示する滞留部形成部材40A、40Bでは、隙間W1、W2の幅が時間の経過と共に大きくなり、液状のガラス原料M(L)を堰き止める機能が低下する。この場合、円筒管20A、20B内において、ガラス原料M(L)を一時的に滞留させることが困難となる。   The materials constituting the cylindrical tube 20, the retention portion forming member 40, and the block-shaped member 50 illustrated in FIGS. 1 to 4 are resistant to the corrosion resistance to the glass raw material M and the temperature at which the glass raw material M is heated and melted. A material having high heat resistance is used, and quartz glass is usually used. However, when the process of heating and melting the glass raw material M is carried out for a long time, the materials constituting the cylindrical tube 20, the retention part forming member 40, and the block-like member 50 are gradually eroded. For this reason, in the stay part forming members 40A and 40B illustrated in FIGS. 2 and 3, the widths of the gaps W1 and W2 increase with time, and the function of blocking the liquid glass raw material M (L) is lowered. In this case, it becomes difficult to temporarily retain the glass raw material M (L) in the cylindrical tubes 20A and 20B.

このような問題の発生を防止するためには、滞留部S内に、予め、滞留部形成部材40A、40Bの堰高さ(円筒管20A、20Bの直径方向の長さ)の数分の1以下のサイズを有する複数個の阻害部材を密集して配置しておくことが好ましい。   In order to prevent the occurrence of such a problem, in the stay portion S, a fraction of the weir height (the length in the diameter direction of the cylindrical tubes 20A and 20B) of the stay portion forming members 40A and 40B is previously obtained. It is preferable that a plurality of inhibitory members having the following sizes are arranged densely.

図5は、図2(A)に示す滞留部S内に複数個の阻害部材を密集して配置した例を示す模式図である。ここで、図5(A)は、ガラス原料Mの加熱・溶解処理を開始し始めた初期の時点を示す図であり、図5(B)は、ガラス原料Mの加熱・溶解処理の開始後、滞留部形成部材40Aの侵食がある程度進行した時点を示す図である。図5に示す阻害部材60は、滞留部形成部材40Aの堰高さの数分の1〜数十分の1程度のサイズを有する部材であり、滞留部S内に密集して配置されている。なお、阻害部材60は、円筒管20、滞留部形成部材40、ブロック状部材50を構成する材料と同様の材料からなり、その形状としては、たとえば、球状、棒状、多面体状、筒状等の形状が適宜選択できる。   FIG. 5 is a schematic diagram showing an example in which a plurality of inhibitory members are densely arranged in the staying portion S shown in FIG. Here, FIG. 5A is a diagram illustrating an initial time point at which the heating / melting treatment of the glass raw material M is started, and FIG. 5B is a diagram after the heating / melting treatment of the glass raw material M is started. It is a figure which shows the time of erosion of the stay part formation member 40A progressing to some extent. The obstructing member 60 shown in FIG. 5 is a member having a size of about one-tenth to several tenths of the weir height of the staying portion forming member 40A, and is densely arranged in the staying portion S. . The inhibition member 60 is made of the same material as the material constituting the cylindrical tube 20, the staying portion forming member 40, and the block-like member 50. Examples of the shape include a spherical shape, a rod shape, a polyhedral shape, and a cylindrical shape. The shape can be selected as appropriate.

ここで、滞留部形成部材40Aの液状のガラス原料M(L)を堰き止める機能が低下し、図5(B)に示すように液面Lが大幅に低下した場合、液状のガラス原料M(L)は、阻害部材60同士の間を液状のガラス原料M(L)が流れることになる。この場合、阻害部材60が密集して配置されており、阻害部材60間の隙間は非常に小さいため、阻害部材60同士の間を液状のガラス原料M(L)の流動抵抗は非常に大きくなる。すなわち、滞留部形成部材40Aの液状のガラス原料M(L)を堰き止める機能が低下し、図5(B)に示すように液面Lが大幅に低下した場合、阻害部材60は、ガラス原料M(L)の、円筒管20Aの長手方向に対するスムーズな移動を一時的に妨げる障害物としての機能を発揮する。   Here, when the function of blocking the liquid glass raw material M (L) of the staying portion forming member 40A is reduced and the liquid level L is significantly reduced as shown in FIG. 5B, the liquid glass raw material M ( In L), the liquid glass raw material M (L) flows between the inhibition members 60. In this case, since the inhibiting members 60 are densely arranged and the gap between the inhibiting members 60 is very small, the flow resistance of the liquid glass raw material M (L) between the inhibiting members 60 becomes very large. . That is, when the function of blocking the liquid glass raw material M (L) of the staying portion forming member 40A is reduced and the liquid level L is significantly reduced as shown in FIG. The function of M (L) as an obstacle that temporarily prevents the smooth movement of the cylindrical tube 20A in the longitudinal direction is exhibited.

以上に説明した本実施形態のガラス原料粗溶解物の製造方法およびこれを用いた光学ガラスの製造方法は、リン酸塩系の光学ガラスの製造に特に好適である。リン酸塩系のガラス組成では、従来のガラス原料粗溶解物の製造方法およびこれを用いた光学ガラスの製造方法では、着色が生じ易かったが、本実施形態のガラス原料粗溶解物の製造方法およびこれを用いた光学ガラスの製造方法では、このような着色をより効果的に抑制できる。   The above-described method for producing a glass raw material crude melt and the method for producing optical glass using the same are particularly suitable for the production of phosphate-based optical glass. In the phosphate-based glass composition, the conventional glass raw material crude melt manufacturing method and the optical glass manufacturing method using the same were easily colored, but the glass raw material crude melt manufacturing method of the present embodiment And in the manufacturing method of optical glass using this, such coloring can be suppressed more effectively.

以下に、本発明を実施例を挙げて説明するが、本発明は以下の実施例にのみ限定されるものでは無い。   Hereinafter, the present invention will be described with reference to examples. However, the present invention is not limited to the following examples.

(実施例A1)
−原料溶解炉−
原料溶解炉10としては、円筒管20内が図3に示す構成からなるものを用いた。円筒管20Bおよびその内部に配置された各部材の構成材料は、全て石英ガラスからなる。ここで、円筒管20Bの寸法形状は、長さ:100cm、外径:10cm、内径:8cmであり、滞留部形成部材40Bは、厚み:5cm、外径:8cm、内径:6cmのリング状部材を、周方向に等間隔に8等分した後、円筒管20B内に配置し易いように、適宜形状を整えたものである。円筒管20B内に配置した互いに隣接する2つの滞留部形成部材40B間の隙間は約1mm前後である。また、ブロック状部材50は、滞留部形成部材40Bの作製に用いたリング状部材と同じ厚みのリング状部材を適宜切断して作製した。なお、滞留部形成部材40B、ブロック状部材50は、円筒管20Bの流出口24側から約20cmの位置に配置した。円筒管20Bの傾斜角θは3度に設定した。また、円筒管20Bの流出口24の近傍には、温度をモニターするための熱電対を配置した。
(Example A1)
-Raw material melting furnace-
As the raw material melting furnace 10, the one in which the inside of the cylindrical tube 20 has the configuration shown in FIG. 3 was used. The constituent materials of the cylindrical tube 20B and each member disposed therein are all made of quartz glass. Here, the dimensions and shape of the cylindrical tube 20B are a length: 100 cm, an outer diameter: 10 cm, an inner diameter: 8 cm, and the staying portion forming member 40B is a ring-shaped member having a thickness: 5 cm, an outer diameter: 8 cm, and an inner diameter: 6 cm. After being equally divided into eight in the circumferential direction, the shape is appropriately adjusted so that it can be easily placed in the cylindrical tube 20B. The gap between two staying portion forming members 40B arranged adjacent to each other in the cylindrical tube 20B is about 1 mm. Moreover, the block-shaped member 50 was produced by appropriately cutting a ring-shaped member having the same thickness as the ring-shaped member used for producing the staying portion forming member 40B. In addition, the retention part formation member 40B and the block-shaped member 50 were arrange | positioned in the position of about 20 cm from the outflow port 24 side of the cylindrical tube 20B. The inclination angle θ of the cylindrical tube 20B was set to 3 degrees. Further, a thermocouple for monitoring the temperature was disposed near the outlet 24 of the cylindrical tube 20B.

また、滞留部形成部材40Bにより形成される滞留部内には、外径10mm〜20mmの20〜30個のガラス片からなる阻害部材60を密集して配置した。なお阻害部材60は円筒管20と同じ材料からなる。   Further, in the staying part formed by the staying part forming member 40B, the inhibition members 60 made of 20 to 30 glass pieces having an outer diameter of 10 mm to 20 mm were densely arranged. The inhibition member 60 is made of the same material as the cylindrical tube 20.

抵抗発熱体30としては、円筒管20Bと同程度の長さを有する棒状のSiCヒータ、円筒管20Bと略平行を成すように、円筒管20Bの周囲に複数本配置した。さらに、流出口24の下方には、流出口24から流出する融液を急冷して、ガラス原料粗溶解物(カレット)を得るために、水槽WBを配置した。   A plurality of resistance heating elements 30 are arranged around the cylindrical tube 20B so as to be substantially parallel to the cylindrical SiC tube 20B and a rod-shaped SiC heater having the same length as the cylindrical tube 20B. Further, below the outflow port 24, a water tank WB was disposed in order to rapidly cool the melt flowing out from the outflow port 24 to obtain a glass raw material crude melt (cullet).

(原料)
原料から水、炭酸ガス等の加熱によりガス化する成分を除外した後の酸化物換算で、下記組成からなるリン酸塩系光学ガラス製造用の原料(ガラス原料MA)を準備した。なお、原料の調合に際しては、下記に示す各成分のうち、Pについては、正燐酸(HPO)、メタリン酸又は五酸化二燐等を用い、その他の成分については、炭酸塩、硝酸塩、酸化物等を用いた。
:17質量%
Nb:22.3質量%
Bi:43.5質量%
WO:8.6質量%
BaO:0.7質量%
:0.6質量%
TiO:2.6質量%
LiO:0.8質量%
NaO:3質量%
O:0.9質量%
合計:100質量%
Sbを外割りで0.2質量%添加
(material)
A raw material (glass raw material MA) for producing a phosphate optical glass having the following composition was prepared in terms of oxide after excluding components gasified by heating such as water and carbon dioxide from the raw material. In preparing the raw materials, among the components shown below, for P 2 O 5 , orthophosphoric acid (H 3 PO 4 ), metaphosphoric acid, phosphorous pentoxide or the like is used, and for other components, carbonic acid is used. Salts, nitrates, oxides and the like were used.
P 2 O 5 : 17% by mass
Nb 2 O 5: 22.3% by weight
Bi 2 O 5: 43.5 wt%
WO 5 : 8.6% by mass
BaO: 0.7 mass%
B 2 O 3 : 0.6% by mass
TiO 2 : 2.6% by mass
Li 2 O: 0.8% by mass
Na 2 O: 3% by mass
K 2 O: 0.9% by mass
Total: 100% by mass
Add 0.2% by mass of Sb 2 O 3

−カレットの作製−
SiCヒータにより、円筒管20Bを1100度前後まで加熱した。続いて、円筒管20Bの加熱温度を1100度に維持しつつ、投入口22側から、粉末状のガラス原料MAを投入した。なお、ガラス原料MAは、一定の時間間隔で1kgづつ投入した。また、円筒管20Bは、中心軸Cを回転軸として、原料MAを加熱、溶解する度に一定の角度づつ回転させた。そして、円筒管20B内で、融液状となったガラス原料MAを、流出口24側から流出させ、水槽WB中にて急冷し、カレットを得た。
-Production of cullet-
The cylindrical tube 20B was heated to around 1100 degrees by a SiC heater. Subsequently, while maintaining the heating temperature of the cylindrical tube 20B at 1100 degrees, the powdery glass raw material MA was charged from the inlet 22 side. The glass raw material MA was added by 1 kg at regular time intervals. The cylindrical tube 20B was rotated by a certain angle each time the raw material MA was heated and melted with the central axis C as the rotation axis. And in the cylindrical tube 20B, the glass raw material MA which became a molten liquid was flowed out from the outflow port 24 side, and rapidly cooled in the water tank WB, and the cullet was obtained.

−本溶解および光学ガラスの作製−
得られたカレット2kgを、白金坩堝に投入し、約1100度で4時間の本溶解を実施し、得られたガラスを、徐冷炉にて徐冷し、屈折率ndが2.0027、アッベ数νdが19.3の光学ガラスを得た。
-Main melting and production of optical glass-
2 kg of the obtained cullet was put into a platinum crucible, and the main melting was carried out at about 1100 degrees for 4 hours. The obtained glass was gradually cooled in a slow cooling furnace, the refractive index nd was 2.0027, the Abbe number νd Of 19.3 was obtained.

(実施例A2)
原料溶解炉10の円筒管20内の構造として、阻害部材60も併用した図3に示す構造の代わりに、図4に示す構造を採用した以外は、実施例A1で用いた原料溶解炉10と同様の構造を有する原料溶解炉10を用いた。ここで、円筒管20Cの寸法形状は、実施例A1で用いた円筒管20Bと同様である。また、滞留部形成部材40Cは、円筒管20Cと同じ材料からなるリング状部材を、周方向に等間隔に4等分した後、円筒管20C内に配置し易いように、適宜形状を整えたものである。なお、滞留部形成部材40Cは、実施例A1と同様に、円筒管20Cの流出口24側から約20cmの位置に配置した。円筒管20Cの傾斜角θは実施例A1と同様に3度に設定した。また、円筒管20Cの外周面の中央部近傍には、温度をモニターするための熱電対を配置した。
(Example A2)
The raw material melting furnace 10 used in Example A1 is the same as the structure in the cylindrical tube 20 of the raw material melting furnace 10 except that the structure shown in FIG. 4 is adopted instead of the structure shown in FIG. A raw material melting furnace 10 having a similar structure was used. Here, the dimensional shape of the cylindrical tube 20C is the same as the cylindrical tube 20B used in Example A1. In addition, the retaining portion forming member 40C was appropriately shaped so that a ring-shaped member made of the same material as that of the cylindrical tube 20C was equally divided into four in the circumferential direction so that it could be easily placed in the cylindrical tube 20C. Is. In addition, the retention part formation member 40C was arrange | positioned in the position of about 20 cm from the outflow port 24 side of the cylindrical tube 20C similarly to Example A1. The inclination angle θ of the cylindrical tube 20C was set to 3 degrees as in Example A1. In addition, a thermocouple for monitoring temperature was disposed near the center of the outer peripheral surface of the cylindrical tube 20C.

そして、実施例A1と同様にして、カレットを作製し、本溶解を行い光学ガラスを得た。   And it carried out similarly to Example A1, the cullet was produced, this melt | dissolution was performed, and the optical glass was obtained.

(比較例A1)
実施例A1で用いた原料溶解炉10において、円筒管20内から、滞留部形成部材40B、ブロック状部材50および阻害部材60を除外した原料溶解炉を用いた以外は、実施例A1と同様にしてカレットを作製し、本溶解を行い光学ガラスを得た。
(Comparative Example A1)
In the raw material melting furnace 10 used in Example A1, the same procedure as in Example A1 was used, except that the raw material melting furnace excluding the retention portion forming member 40B, the block-shaped member 50, and the inhibiting member 60 was used from the cylindrical tube 20. A cullet was prepared and melted to obtain an optical glass.

(評価)
実施例A1および実施例A2で得られた光学ガラスについては、分光光度計により、300nm〜700nmの範囲内にて、透過率の測定を行った。これら実施例A1および実施例A2の光学ガラスは、波長500nm前後から透過率が低下し、波長400nm前後で透過率がほぼゼロとなる光学特性を有していた。ここで、透過率が70%となる波長(λ70)を求めた。結果を表1に示す。なお比較例A1で得られたガラスは着色が著しく、光学ガラスとしては適さないものであった。このように実施例A1、A2、比較例B1のガラス組成は同じであるが、その製法の違いによって、実施例A1、A2では光学ガラスとして好適なガラスを得ることができたが、比較例A1のガラスは光学ガラスとしては適さない著しく着色したガラスであった。
(Evaluation)
About the optical glass obtained in Example A1 and Example A2, the transmittance | permeability was measured in the range of 300 nm-700 nm with the spectrophotometer. These optical glasses of Example A1 and Example A2 had optical characteristics such that the transmittance decreased from around 500 nm and the transmittance became almost zero at around 400 nm. Here, the wavelength (λ70) at which the transmittance is 70% was determined. The results are shown in Table 1. The glass obtained in Comparative Example A1 was extremely colored and was not suitable as an optical glass. As described above, the glass compositions of Examples A1 and A2 and Comparative Example B1 were the same, but due to the difference in the production method, in Examples A1 and A2, a glass suitable as an optical glass could be obtained, but Comparative Example A1. This glass was a highly colored glass that was not suitable as an optical glass.

Figure 2014111544
Figure 2014111544

表1に示す結果からは、実施例A1,A2の光学ガラスの方が、比較例A1の光学ガラスよりも可視光の短波長域において、より幅広い波長で光を透過し易い(着色し難しい)ことが判った。また、実施例A1の光学ガラスの方が、実施例A2の光学ガラスよりも可視光の短波長域において、より幅広い波長で光を透過し易い(着色し難しい)ことが判った。   From the results shown in Table 1, the optical glasses of Examples A1 and A2 are more likely to transmit light at a wider wavelength in the short wavelength range of visible light than the optical glass of Comparative Example A1 (it is difficult to color). I found out. Moreover, it turned out that the optical glass of Example A1 is easy to permeate | transmit light with a wider wavelength (it is difficult to color) in the short wavelength range of visible light than the optical glass of Example A2.

(実施例A3)
実施例A1において用いた円筒管20Bの代わりに、この円筒管20Bを、中心軸Cを含む平面で実質的に2分割して得られた半円筒管(図6に示す樋状部材100)を用いた。この樋状部材100は、円筒管20Bを2分割した構造を有する点を除けば、その他の寸法や構成材料は、円筒管20Bと同様である。また、円筒管20B内に配置される滞留部形成部材40Bおよびブロック状部材50についても、その配置個数を半分にして、図6に示すように、樋状部材100の内周面に配置した。そして、樋状部材100を回転させなかった点を除いて、実施例A1と同様に滞留部内に阻害部材60を配置し、実施例A1と同様の条件にてカレットを作製した。その結果、λ70は実施例A1と概ね同程度の値を示した。
(Example A3)
Instead of the cylindrical tube 20B used in Example A1, a semi-cylindrical tube (saddle-shaped member 100 shown in FIG. 6) obtained by dividing the cylindrical tube 20B into two substantially by a plane including the central axis C is used. Using. Except for the point that the bowl-shaped member 100 has a structure in which the cylindrical tube 20B is divided into two, other dimensions and constituent materials are the same as those of the cylindrical tube 20B. Further, the staying portion forming member 40B and the block-like member 50 arranged in the cylindrical tube 20B were also halved and arranged on the inner peripheral surface of the bowl-shaped member 100 as shown in FIG. Then, except that the saddle-shaped member 100 was not rotated, the inhibiting member 60 was arranged in the stay portion as in Example A1, and a cullet was produced under the same conditions as in Example A1. As a result, λ70 was almost the same value as in Example A1.

(実施例B1)
実施例B1において、ガラス原料Mとして、下記に示す下記組成からなるリン酸塩系光学ガラス製造用のガラス原料MBを使用した。そして、円筒管20Bの加熱温度を1240度に変更した以外は、実施例A1と同様にしてカレットを作製し、本溶解を行い光学ガラスを得た。
:20質量%
Nb:43質量%
BaO:19.5質量%
:3質量%
TiO:8質量%
NaO:3.5質量%
O:1質量%
ZnO:1質量%
ZrO:1質量%
合計:100質量%
Sbを外割りで0.3質量%添加
(Example B1)
In Example B1, as the glass raw material M, a glass raw material MB for producing phosphate optical glass having the following composition shown below was used. Then, except that the heating temperature of the cylindrical tube 20B was changed to 1240 degrees, a cullet was produced in the same manner as in Example A1, and was melted to obtain an optical glass.
P 2 O 5 : 20% by mass
Nb 2 O 5 : 43% by mass
BaO: 19.5 mass%
B 2 O 3 : 3% by mass
TiO 2 : 8% by mass
Na 2 O: 3.5% by mass
K 2 O: 1% by mass
ZnO: 1% by mass
ZrO 2 : 1% by mass
Total: 100% by mass
Add 0.3% by mass of Sb 2 O 3

(実施例B2)
実施例B2において、ガラス原料Mとして、ガラス原料MBを使用し、円筒管20Cの温度を実施例B1と同様に設定した以外は、実施例A2と同様にしてカレットを作製し、本溶解を行い光学ガラスを得た。
(Example B2)
In Example B2, a glass raw material MB was used as the glass raw material M, and a cullet was prepared and melted in the same manner as in Example A2, except that the temperature of the cylindrical tube 20C was set in the same manner as in Example B1. Optical glass was obtained.

(比較例B1)
比較例B1において、ガラス原料Mとして、ガラス原料MBを使用し、円筒管の温度を実施例B1と同様に設定した以外は、実施例B1と同様にしてカレットを作製し、本溶解を行い、屈折率ndが1.9236、アッベ数νdが20.9の光学ガラスを得た。
(Comparative Example B1)
In Comparative Example B1, a glass raw material MB was used as the glass raw material M, and a cullet was prepared in the same manner as in Example B1, except that the temperature of the cylindrical tube was set in the same manner as in Example B1, and this melting was performed. An optical glass having a refractive index nd of 1.9236 and an Abbe number νd of 20.9 was obtained.

(評価)
実施例B1、実施例B2および比較例B1で得られた光学ガラスについては、実施例A1の光学ガラスと同様の評価を行った。結果を表2に示す。実施例B1、実施例B2の光学ガラスは、実施例A1、実施例A2の光学ガラスよりも屈折率ndが低い分、高屈折率付与成分であるNb、TiO、BiおよびWOの合計含有量が少なく、着色が少ないガラス組成となっているが、ガラス組成が同じでも実施例B1、B2と比較例B1との間には表2に示すように着色の指標であるλ70において大きな差が見られた。
(Evaluation)
About the optical glass obtained by Example B1, Example B2, and Comparative Example B1, evaluation similar to the optical glass of Example A1 was performed. The results are shown in Table 2. In the optical glass of Example B1 and Example B2, the refractive index nd is lower than that of the optical glass of Example A1 and Example A2, and thus Nb 2 O 5 , TiO 2 , and Bi 2 O 3 that are high refractive index imparting components. And the total content of WO 3 is low and the glass composition is less colored. However, even if the glass composition is the same, there is a coloring index between Examples B1 and B2 and Comparative Example B1 as shown in Table 2. A large difference was observed at a certain λ70.

Figure 2014111544
Figure 2014111544

10 原料溶解炉
20、20A、20B、20C 円筒管(筒状部材、原料処理部材)
22 投入口
24 流出口
26 内周面
30 抵抗発熱体
40、40A、40B、40C 滞留部形成部材
40AI 内周面
50 ブロック状部材
60 阻害部材
100 半円筒管(樋状部材、原料処理部材)
10 Raw material melting furnace 20, 20A, 20B, 20C Cylindrical tube (tubular member, raw material processing member)
22 Inlet 24 Outlet 26 Inner peripheral surface 30 Resistance heating element 40, 40A, 40B, 40C Stay part forming member 40AI Inner peripheral surface 50 Block member 60 Inhibiting member 100 Semi-cylindrical tube (saddle member, raw material processing member)

本発明は、ガラス原料粗溶解物の製造方法および光学ガラスの製造方法に関するものである。   The present invention relates to a method for producing a glass raw material crude melt and a method for producing optical glass.

ガラス原料を加熱、溶融してガラスを製造する場合、溶融物が坩堝を強く侵蝕する。そして、この際の侵蝕力は、ガラス原料がガラス化する際に顕著であるが、ガラス化した後はさほど大きくは無い。このため、ガラスを製造する場合において、ガラス原料を一旦、粗溶解した後、急冷して得られた粗溶解物を作製し、この粗溶解物を用いて本溶解する製造方法が利用されている。この製造方法では、ガラス原料をそのまま用いて本溶解する製造方法と比べて、本溶解時の坩堝の侵蝕を抑制できる。このような製造方法は、坩堝材料として使用される白金に対する侵蝕力の大きい光学ガラスを製造する場合に利用されている。   When a glass raw material is heated and melted to produce glass, the melt strongly erodes the crucible. The erosion force at this time is remarkable when the glass raw material is vitrified, but is not so great after vitrification. For this reason, in the case of producing glass, a production method is used in which a glass raw material is roughly melted once, then a crude melt obtained by rapid cooling is prepared, and this coarse melt is used for main melt. . In this manufacturing method, the crucible erosion during the main melting can be suppressed as compared with the manufacturing method in which the glass raw material is used as it is for the main melting. Such a manufacturing method is used when manufacturing an optical glass having a large erosive force against platinum used as a crucible material.

ここで、粗溶解物の製造には、ガラス原料を加熱して粗溶解するための石英管を備えた原料溶解炉が用いられる(特許文献1,2参照)。この原料溶解炉は、中心軸を水平方向に対して一定の角度を成すように傾斜させて配置した石英管と、この石英管を加熱する抵抗発熱体等とを備えている。そして、粗溶解物を製造する場合、まず、石英管の一方の開口部(投入口)からガラス原料を投入する。そして、投入口よりも鉛直方向下方側に位置する他方の開口部(流出口)側へと、ガラス原料を移動させながら、ガラス原料を加熱・溶解する。そして、融液状となったガラス原料を、流出口の下方に配置された水槽中に投入し、急冷することで、粗溶解物を得る。   Here, a raw material melting furnace equipped with a quartz tube for heating and roughly melting a glass raw material is used for the production of the coarse melt (see Patent Documents 1 and 2). This raw material melting furnace includes a quartz tube arranged with its central axis inclined at a certain angle with respect to the horizontal direction, and a resistance heating element for heating the quartz tube. And when manufacturing a coarse melt, first, glass raw material is supplied from one opening part (input port) of a quartz tube. And a glass raw material is heated and melt | dissolved, moving a glass raw material to the other opening part (outflow port) side located in a perpendicular direction lower side rather than an injection port. And the glass raw material used as the melt state is thrown into the water tank arrange | positioned under the outflow port, and a rough melt is obtained by quenching.

特開昭62−123027号公報JP-A-62-213027 特開平1−119522号公報JP-A-1-119522

しかしながら、特許文献1,2に例示されるような従来のガラス原料の加熱・溶解に用いられる石英管は、内周面が平滑で凹凸の無い面からなる単なる円筒管である。このため、投入口から石英管内に投入された原料が、投入口側から流出口側へと移動する際に、その移動が全く阻害されない。すなわち、原料は、石英管内を加熱・溶解しながら、石英管内にて滞留することなく投入口側から流出口側へとスムーズに移動し、流出口から水槽へと流れ落ちることになる。このため、石英管内にて原料を長時間に亘って加熱・溶解することができない。   However, the conventional quartz tube used for heating and melting the glass raw material as exemplified in Patent Documents 1 and 2 is a simple cylindrical tube having a smooth inner peripheral surface and no uneven surface. For this reason, when the raw material thrown into the quartz tube from the inlet port moves from the inlet side to the outlet side, the movement is not hindered at all. That is, the raw material smoothly moves from the inlet side to the outlet side without staying in the quartz tube while heating and melting in the quartz tube, and flows down from the outlet to the water tank. For this reason, a raw material cannot be heated and melt | dissolved for a long time in a quartz tube.

しがたって、粗溶解物を製造する際に、ガラス原料の加熱・溶解が不十分となり、粗溶解物のガラス化度合が低くなりやすい。すなわち、粗溶解物の白金坩堝に対する侵蝕力は、ガラス化度合が最も低いガラス原料により近づくことになる。このため、得られた粗溶解物は、ガラス原料と比べて白金に対する侵蝕力は大幅に低下しても、本溶解時に侵蝕によって混入した白金に起因する着色が生じ易くなる。   Therefore, when manufacturing the coarsely melted product, the heating and melting of the glass raw material becomes insufficient, and the vitrification degree of the crudely melted product tends to be low. That is, the erosion force of the coarsely melted material on the platinum crucible approaches the glass raw material having the lowest vitrification degree. For this reason, even if the obtained coarse melt | dissolution material reduces the erosion power with respect to platinum significantly compared with a glass raw material, it becomes easy to produce coloring resulting from platinum mixed by erosion at the time of this melt | dissolution.

このような問題を解決するためには、石英管内のガラス原料をより高温で加熱・溶解することも考えられる。しかしながら、通常、光学ガラスには、様々な種類の金属が含まれている。そして、これらの金属のうち、いくつかの金属は、より高温で加熱されると還元され、その結果、光学ガラスを着色させてしまう場合もある。   In order to solve such a problem, it is conceivable to heat and melt the glass material in the quartz tube at a higher temperature. However, optical glasses usually contain various types of metals. Among these metals, some metals are reduced when heated at higher temperatures, and as a result, the optical glass may be colored.

本発明は、上記事情に鑑みてなされたものであり、ガラス原料粗溶解物を用いて製造される光学ガラスの着色を抑制し、生産性を向上できるガラス原料粗溶解物の製造方法およびこれを用いた光学ガラスの製造方法を提供することを課題とする。 The present invention has been made in view of the above circumstances, to suppress the coloration of optical glass produced using the glass raw material crude lysate method of manufacturing a glass material crude lysate that can be improved productivity and which It is an object of the present invention to provide a method for producing optical glass using a glass.

上記課題は以下の本発明により達成される。すなわち、
本発明のガラス原料粗溶解物製造方法は、一方の端部に投入口を備え、他方の端部に流出口を備え、投入口が流出口よりも鉛直方向に対して上方側に位置するように配置され、かつ、筒状および樋状から選択される形状を有する原料処理部材の投入口から、ガラス原料を原料処理部材内に供給する原料供給工程と、原料処理部材内に供給されたガラス原料を、投入口から、流出口へと移動させつつ加熱・溶解する加熱・溶解工程と、流出口から流れ落ちるガラス原料の融液を、冷却して、固化する固化工程と、を少なくとも経てガラス原料粗溶解物を製造し、原料処理部材内の投入口から流出口側へガラス原料を移動させる際に、原料処理部材内においてガラス原料を一時的に滞留させることを特徴とする。
The above-mentioned subject is achieved by the following present invention. That is,
The glass raw material crude melt production method of the present invention includes an inlet at one end, an outlet at the other end, and the inlet is positioned above the outlet in the vertical direction. The raw material supply step of supplying the glass raw material into the raw material processing member from the inlet of the raw material processing member having a shape selected from a cylindrical shape and a bowl shape, and the glass supplied into the raw material processing member Glass raw material through at least a heating / melting step of heating and melting while moving the raw material from the inlet to the outlet and a solidifying step of cooling and solidifying the melt of the glass raw material flowing down from the outlet When the crude melt is produced and the glass raw material is moved from the inlet to the outlet side in the raw material processing member, the glass raw material is temporarily retained in the raw material processing member.

本発明のガラス原料粗溶解物製造方法の一実施態様は、ガラス原料が、Ti化合物、Nb化合物、W化合物、Bi化合物およびLa化合物から選択される少なくともいずれか1種の金属を含むものであることが好ましい。   In one embodiment of the method for producing a crude raw material for glass raw material of the present invention, the glass raw material contains at least one metal selected from a Ti compound, an Nb compound, a W compound, a Bi compound, and an La compound. preferable.

本発明のガラス原料粗溶解物製造方法の実施態様は、原料処理部材が筒状部材からなり、筒状部材内に、ガラス原料を一時的に滞留させるための滞留部形成部材が、筒状部材の中心軸に対して、略点対称を成すように配置され、かつ、加熱・溶解工程において、筒状部材を、筒状部材の中心軸を回転軸として回転させることが好ましい。 In one embodiment of the method for producing a glass raw material crude melt according to the present invention, the raw material processing member is formed of a cylindrical member, and the retention portion forming member for temporarily retaining the glass raw material in the cylindrical member is cylindrical. It is preferably arranged so as to be substantially point-symmetric with respect to the central axis of the member, and in the heating / melting step, the cylindrical member is rotated about the central axis of the cylindrical member as a rotation axis.

本発明の光学ガラスの製造方法は、本発明のガラス原料粗溶解物の製造方法によりガラス原料粗溶解物を作製し、このガラス原料粗溶解物を、貴金属または貴金属合金製の容器にて本溶解する本溶解工程を少なくとも経て、光学ガラスを製造することを特徴とする。   The method for producing an optical glass of the present invention is to prepare a glass raw material crude melt by the method for producing a glass raw material crude melt of the present invention, and this glass raw material crude melt is melted in a noble metal or noble metal alloy container. The optical glass is manufactured through at least the main melting step.

本発明によれば、ガラス原料粗溶解物を用いて製造される光学ガラスの着色を抑制できるガラス原料粗溶解物の製造方法およびこれを用いた光学ガラスの製造方法を提供することができる。   ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the glass raw material rough melt which can suppress the coloring of the optical glass manufactured using a glass raw material rough melt, and the manufacturing method of optical glass using the same can be provided.

本実施形態のガラス原料粗溶解物の製造方法に用いられる原料溶解炉の一例を示す模式図である。It is a schematic diagram which shows an example of the raw material melting furnace used for the manufacturing method of the glass raw material coarse melt of this embodiment. 図1に示す原料溶解炉に用いる筒状部材(円筒管)の一例を示す模式図である。ここで、図2(A)は図1に示す円筒管を、その中心軸を含む平面で切断した場合の端面図の一例を示し、図2(B)は、図2(A)に示す円筒管を流出口側から見た平面図の一例を示すものである。It is a schematic diagram which shows an example of the cylindrical member (cylindrical tube) used for the raw material melting furnace shown in FIG. Here, FIG. 2 (A) shows an example of an end view when the cylindrical tube shown in FIG. 1 is cut along a plane including its central axis, and FIG. 2 (B) shows the cylinder shown in FIG. 2 (A). An example of the top view which looked at the pipe | tube from the outflow port side is shown. 図1に示す原料溶解炉に用いる筒状部材(円筒管)の他の例を示す平面図である。It is a top view which shows the other example of the cylindrical member (cylindrical pipe) used for the raw material melting furnace shown in FIG. 図1に示す原料溶解炉に用いる筒状部材(円筒管)の他の例を示す平面図であるIt is a top view which shows the other example of the cylindrical member (cylindrical tube) used for the raw material melting furnace shown in FIG. 図2(A)に示す滞留部S内に複数個の阻害部材を密集して配置した例を示す模式図である。FIG. 3 is a schematic diagram illustrating an example in which a plurality of inhibitory members are densely arranged in a staying portion S illustrated in FIG. 図1に示す原料溶解炉に用いる樋状部材(半円筒管)の一例を示す平面図である。It is a top view which shows an example of the bowl-shaped member (semi-cylindrical tube) used for the raw material melting furnace shown in FIG.

本実施形態のガラス原料粗溶解物の製造方法は、一方の端部に投入口を備え、他方の端部に流出口を備え、投入口が流出口よりも鉛直方向に対して(鉛直方向において)上方側に位置するように配置され、かつ、筒状および樋状から選択される形状を有する原料処理部材の投入口から、ガラス原料を原料処理部材内に供給する原料供給工程と、原料処理部材内に供給されたガラス原料を、投入口から、流出口へと移動させつつ加熱・溶解する加熱・溶解工程と、流出口から流れ落ちるガラス原料の融液を、冷却して、固化する固化工程と、を少なくとも経てガラス原料粗溶解物を製造する。ここで、原料処理部材内の投入口から流出口側へガラス原料を移動させる際に、原料処理部材内においてガラス原料を一時的に滞留させる。   The method for producing a glass raw material crude melt according to the present embodiment includes an inlet at one end, an outlet at the other end, and the inlet is perpendicular to the outlet (in the vertical direction). ) A raw material supply step for supplying a glass raw material into the raw material processing member from an inlet of the raw material processing member which is arranged to be positioned on the upper side and has a shape selected from a cylindrical shape and a bowl shape, and a raw material processing A heating / melting process in which the glass raw material supplied into the member is heated and melted while moving from the inlet to the outlet, and a solidification process in which the melt of the glass raw material flowing down from the outlet is cooled and solidified. And at least the glass raw material crude melt is produced. Here, when the glass raw material is moved from the inlet in the raw material processing member to the outlet side, the glass raw material is temporarily retained in the raw material processing member.

なお、本願明細書において「ガラス原料」とは、未ガラス化原料、すなわちバッチ原料を意味する。また、原料処理部材は、筒状の形状を有する部材(筒状部材)、および、樋状の形状を有する部材(樋状部材)のいずれかから選択される。それゆえ、筒状部材では、一方の端部に設けられた開口部が投入口となり、他方の端部に設けられた開口部が流出口となる。また、桶状部材としては、筒状部材の外周面の一部または全部が、この筒状部材の長手方向に沿って開口している部材も含まれる。樋状部材は、長手方向に沿って開口している開口部分が、鉛直方向に対して上方側を向くように配置されることが特に好ましい。この場合、樋状部材内を投入口から流出口側へと移動するガラス原料が、樋状部材からこぼれ落ちるのを抑制することが極めて容易になる。   In the present specification, “glass raw material” means an unvitrified raw material, that is, a batch raw material. Moreover, the raw material processing member is selected from any of a member having a cylindrical shape (cylindrical member) and a member having a bowl-like shape (ridge-like member). Therefore, in the cylindrical member, an opening provided at one end serves as an inlet, and an opening provided at the other end serves as an outlet. Moreover, as a hook-shaped member, the member by which a part or all of the outer peripheral surface of a cylindrical member is opened along the longitudinal direction of this cylindrical member is also contained. It is particularly preferable that the hook-shaped member is disposed so that the opening portion that opens along the longitudinal direction faces upward with respect to the vertical direction. In this case, it becomes very easy to suppress the glass raw material moving from the inlet to the outlet side in the bowl-shaped member from spilling from the bowl-shaped member.

したがって、本実施形態のガラス原料粗溶解物の製造方法では、従来と比べて、原料処理部材内にてより長時間に亘ってガラス原料を加熱・溶解することができる。このため、粗溶解物のガラス化度合をより高めることができ、本溶解時の白金坩堝の侵蝕に起因する光学ガラスの着色を抑制できる。また、本実施形態のガラス原料粗溶解物の製造方法では、ガラス原料の加熱・溶解に際して、粗溶解物のガラス化度合をより高めるために、加熱時間をより長くすることができるため、加熱温度をより高くしなくてもよい。言い換えれば、従来のガラス原料粗溶解物の製造方法で作製された粗溶解物と同程度のガラス化度合を得るために、ガラス原料を、より低温で、より長時間、加熱・溶解することができる。このため、ガラス原料中に、高温下での還元反応により光学ガラスを着色させ易い金属が含まれていても、本実施形態のガラス原料粗溶解物の製造方法では、これら金属の還元反応に起因する光学ガラスの着色も容易に抑制できる。   Therefore, in the manufacturing method of the glass raw material coarse melt of this embodiment, compared with the past, a glass raw material can be heated and melt | dissolved over a longer time within a raw material processing member. For this reason, the vitrification degree of the coarsely dissolved material can be further increased, and coloring of the optical glass due to the erosion of the platinum crucible during the main melting can be suppressed. Further, in the method for producing a glass material crude melt according to the present embodiment, the heating time can be further increased in order to increase the vitrification degree of the crude melt when heating and melting the glass material. Need not be higher. In other words, in order to obtain the same degree of vitrification as a crude melt produced by the conventional method for producing a raw material crude melt, it is possible to heat and melt the glass raw material at a lower temperature for a longer time. it can. For this reason, even if the glass raw material contains a metal that easily colors the optical glass by a reduction reaction at a high temperature, the method for producing a crude raw material for glass raw material according to the present embodiment results from the reduction reaction of these metals. The coloring of the optical glass can be easily suppressed.

高温下での還元反応により光学ガラスを着色させ易い金属成分としては、Ti、Nb、W、Bi等が挙げられ、これらの中でも、光学ガラスに対する着色性の高さ、または、多くの光学ガラスにおいて用いられる汎用性という観点から、前記金属成分として、TiおよびNbが挙げられる。このような観点からは、本実施形態のガラス原料溶解物の製造方法に用いられるガラス原料は、Ti化合物、Nb化合物、W化合物およびBi化合物から選択される少なくともいずれか1種の金属を含むことが特に好ましい。さらにLa化合物などの希土類化合物は溶解しにくい成分であることから溶解温度を高くしなければならない。溶解温度が高くなると侵蝕性が高くなったり、上記着色しやすい金属成分が還元して、ガラスが着色しやすくなる。このため、本実施形態のガラス原料溶解物の製造方法は、希土類化合物、特にLa化合物を含むガラス原料溶解物の製造に好適である。以上より、本実施形態のガラス原料溶解物の製造方法に用いられるガラス原料は、Ti化合物、Nb化合物、W化合物、Bi化合物およびLa化合物から選択される少なくともいずれか1種の金属を含むことが特に好ましい。   Examples of the metal component that easily colors the optical glass by a reduction reaction at high temperature include Ti, Nb, W, Bi, etc. Among these, high colorability for optical glass, or in many optical glasses From the viewpoint of versatility used, examples of the metal component include Ti and Nb. From such a viewpoint, the glass raw material used in the method for producing a glass raw material melt according to the present embodiment includes at least one metal selected from a Ti compound, an Nb compound, a W compound, and a Bi compound. Is particularly preferred. Furthermore, since rare earth compounds such as La compounds are difficult to dissolve, the melting temperature must be increased. When the melting temperature is increased, the erosion property is increased, or the metal components that are easily colored are reduced, and the glass is easily colored. For this reason, the manufacturing method of the glass raw material melt | dissolution of this embodiment is suitable for manufacture of the glass raw material melt | dissolution containing a rare earth compound, especially La compound. As mentioned above, the glass raw material used for the manufacturing method of the glass raw material melt | dissolution of this embodiment contains at least any 1 type of metal selected from Ti compound, Nb compound, W compound, Bi compound, and La compound. Particularly preferred.

なお、本願明細書において、「光学ガラスの着色」とは、光学ガラスに要求される光学特性上、本来高い透過率を有するべき所定の波長域での望ましく無い透過率の低下が起こることを意味し、狭義には可視域の波長範囲での望ましく無い透過率の低下を意味するが、広義には、近赤外域の波長範囲または近紫外域の波長範囲での望ましく無い透過率の低下を意味する場合も含む。   In the specification of the present application, “coloring of optical glass” means that, due to optical characteristics required for optical glass, an undesired decrease in transmittance occurs in a predetermined wavelength region that should originally have high transmittance. In the narrow sense, it means an undesired decrease in transmittance in the visible wavelength range, but in a broad sense, it means an undesired decrease in transmittance in the near-infrared wavelength range or near-ultraviolet wavelength range. This includes cases where

原料処理部材の投入口から流出口へとガラス原料を移動させる際には、原料処理部材内においてガラス原料を一時的に滞留させる。ここで、原料処理部材内においてガラス原料を一時的に滞留させる方法(滞留方法)としては、特に限定されないが、たとえば、(1)原料処理部材内に、ガラス原料の、原料処理部材の長手方向に対するスムーズな移動を一時的に妨げる堰または障害物を配置する方法、および、(2)原料処理部材の内周面に、ガラス原料の溜まり場となる凹部を設ける方法、が挙げられる。ここで、堰としては、内周面に対して突出するように設けられた凸部、投入口側の内径に対して流出口側の内径が小さくなるように内周面に設けられた段差、融液状のガラス原料が通過可能な貫通穴を設けた仕切り板などが一例として挙げられる。   When the glass raw material is moved from the inlet of the raw material processing member to the outlet, the glass raw material is temporarily retained in the raw material processing member. Here, the method of temporarily retaining the glass raw material in the raw material processing member (retention method) is not particularly limited. For example, (1) the longitudinal direction of the raw material processing member of the glass raw material in the raw material processing member And a method of disposing a weir or an obstacle that temporarily hinders smooth movement of the material, and (2) a method of providing a concave portion serving as a reservoir for glass raw material on the inner peripheral surface of the raw material processing member. Here, as the weir, a convex portion provided so as to protrude with respect to the inner peripheral surface, a step provided on the inner peripheral surface so that the inner diameter on the outlet side becomes smaller than the inner diameter on the inlet side, An example is a partition plate provided with a through-hole through which a molten glass material can pass.

ここで、上記(1)の滞留方法では、原料処理部材内を移動するガラス原料が、堰または障害物によって、押し留められたり、移動速度が大幅に低下したりする。このため、ガラス原料が原料処理部材内に一時的に滞留する。また、上記(2)の滞留方法では、原料処理部材内を移動するガラス原料が、凹部に入り込み、この部分で一時的に滞留した後、凹部を溢れ出たガラス原料が再び流出口側へと移動することになる。   Here, in the staying method (1), the glass raw material moving in the raw material processing member is held down by a weir or an obstacle, or the moving speed is greatly reduced. For this reason, the glass raw material is temporarily retained in the raw material processing member. Further, in the retention method (2), the glass material moving in the raw material processing member enters the concave portion, and after temporarily retaining in this portion, the glass raw material overflowing the concave portion returns to the outlet side again. Will move.

次に、本実施形態のガラス原料粗溶解物の製造方法および光学ガラスの製造方法について、各工程別により詳細に説明する。   Next, the manufacturing method of the glass raw material crude melt and the manufacturing method of the optical glass according to the present embodiment will be described in detail for each step.

まず、原料供給工程では、原料処理部材の投入口からガラス原料を投入する。ここで、ガラス原料としては、リン酸を含むガラス原料であれば特に限定されない。なお、リン酸以外のその他のガラス原料を構成する成分としては、Si、Ge、B、Al、Zr、Li、Na、K、Mg、Ca、Sr、Ba、Ti、Nb、Zn、La、Gd、Y、Yb、W、Bi、In、Sc、Te、Ga、Sb等の光学ガラスの製造に用いられる各種元素を含む酸化物、炭酸塩、水酸化物など、公知のガラス製造用の原料が利用できる。また、本溶解時の清澄性を確保するため、ガラス原料を構成する各成分の少なくとも1種類は、炭酸塩等のように、加熱によりガスが発生する成分が選択される。また、ガラス原料は、通常、作製する光学ガラスの組成に応じて各種の成分を適宜混合した粉末状のものが用いられる。   First, in the raw material supply step, the glass raw material is introduced from the inlet of the raw material processing member. Here, the glass raw material is not particularly limited as long as it is a glass raw material containing phosphoric acid. In addition, as components constituting other glass raw materials other than phosphoric acid, Si, Ge, B, Al, Zr, Li, Na, K, Mg, Ca, Sr, Ba, Ti, Nb, Zn, La, Gd There are known raw materials for glass production such as oxides, carbonates and hydroxides containing various elements used in the production of optical glass such as Y, Yb, W, Bi, In, Sc, Te, Ga and Sb. Available. Moreover, in order to ensure the clarity at the time of this melt | dissolution, the component which generate | occur | produces gas by heating like the carbonate etc. is selected as at least 1 type of each component which comprises a glass raw material. In addition, the glass raw material is usually a powdery material in which various components are appropriately mixed according to the composition of the optical glass to be produced.

ガラス原料を原料処理部材の投入口から原料処理部材内に投入する場合は、ガラス原料を連続的に投入してもよく、一定の時間間隔を置いて逐次投入してもよい。また、単位時間当たりのガラス原料の投入量も、原料処理部材のサイズ・構造や、ガラス原料の加熱・溶解条件等に応じて適宜選択することができる。   When the glass raw material is introduced into the raw material processing member from the inlet of the raw material processing member, the glass raw material may be continuously supplied or may be sequentially added at a constant time interval. Also, the amount of glass raw material input per unit time can be appropriately selected according to the size / structure of the raw material processing member, the heating / melting conditions of the glass raw material, and the like.

加熱・溶解工程では、原料処理部材内に投入されたガラス原料を加熱・溶解する。ここで、原料処理部材、ならびに、ガラス原料を原料処理部材内に一時的に滞留させるために必要に応じて原料処理部材内に設けられる堰および障害物を構成する材料としては、ガラス原料に対する耐蝕性および耐熱性を有する耐蝕・耐熱材料が用いられる。このような耐蝕・耐熱材料としては通常、石英ガラスが用いられる。また、原料処理部材ならびに必要に応じて用いられる堰および障害物は、加熱・溶解工程においてガラス原料と接触する部分が耐蝕・耐熱材料から構成されていればよいが、通常は、これら部材全体が耐蝕・耐熱材料から構成される。ここで、原料処理部材が筒状部材からなる場合、加熱・溶解工程の実施に際して、筒状部材は、その中心軸を回転軸として適宜回転させることが好ましい。これにより、筒状部材の内周面の局所的な侵蝕を防ぐことができる。   In the heating / melting step, the glass raw material charged into the raw material processing member is heated / melted. Here, as the material constituting the weir and the obstacle provided in the raw material processing member as necessary in order to temporarily retain the raw material processing member and the glass raw material in the raw material processing member, corrosion resistance to the glass raw material is included. Corrosion and heat resistant materials having heat resistance and heat resistance are used. As such a corrosion-resistant and heat-resistant material, quartz glass is usually used. In addition, the raw material processing member and the weirs and obstacles used as necessary may be made of a corrosion-resistant and heat-resistant material in the portion that contacts the glass raw material in the heating / melting step. Consists of corrosion and heat resistant materials. Here, in the case where the raw material processing member is formed of a cylindrical member, it is preferable that the cylindrical member is appropriately rotated with the central axis as a rotation axis when the heating / dissolution process is performed. Thereby, local erosion of the inner peripheral surface of the cylindrical member can be prevented.

原料処理部材内のガラス原料を加熱する装置としては特に限定されず、抵抗発熱体、重油やガスなどの燃焼加熱等の公知の加熱装置を用いることができ、たとえば、棒状のSiCヒータなどを原料処理部材の周囲に配置することができる。ここで、ガラス原料の加熱温度としては、使用するガラス原料の成分等に応じて適宜選択することができるが、通常は、作製される光学ガラスの液相温度を基準として、流出口近傍の測定温度で、液相温度−100度〜液相温度+500度の範囲内で選択することが好ましく、液相温度−50度〜液相温度+300度の範囲内で選択することがより好ましい。また、投入口は、流出口よりも鉛直方向に対して上方側に位置するように配置されていれば、原料処理部材の中心軸の水平方向に対する傾斜角は特に限定されないが、通常は、1°〜30°の範囲内で設定することが好ましい。また、原料処理部材内に投入された固体状態のガラス原料は、通常、流出口近傍に到達した時点で、ほぼ全量が溶解して融液状となるように、加熱温度や傾斜角等の加熱・溶解条件を設定することが好ましい。   The apparatus for heating the glass raw material in the raw material processing member is not particularly limited, and a known heating apparatus such as a resistance heating element, combustion heating such as heavy oil or gas can be used. For example, a rod-shaped SiC heater or the like is used as a raw material. It can arrange | position around a process member. Here, the heating temperature of the glass raw material can be appropriately selected according to the components of the glass raw material to be used, etc., but usually the measurement in the vicinity of the outlet is based on the liquidus temperature of the produced optical glass. The temperature is preferably selected within the range of liquid phase temperature −100 ° C. to liquid phase temperature + 500 ° C., more preferably selected within the range of liquid phase temperature −50 ° C. to liquid phase temperature + 300 ° C. In addition, the inclination angle of the central axis of the raw material processing member with respect to the horizontal direction is not particularly limited as long as the input port is disposed so as to be positioned above the outflow port with respect to the vertical direction. It is preferable to set within the range of from -30 °. In addition, the solid glass raw material charged into the raw material processing member is usually heated and heated at a heating temperature, an inclination angle, etc. so that almost all of the glass raw material is melted into a molten liquid when it reaches the vicinity of the outlet. It is preferable to set dissolution conditions.

固化工程では、流出口から流れ落ちる融液状のガラス原料を、冷却して、固化する。これによりガラス原料粗溶解物を得る。融液状のガラス原料の冷却方法としては特に限定されないが、通常は、水中に、融液状のガラス原料を投入して急冷する。この場合、粒子状のガラス原料粗溶解物が得られる。なお、水冷した場合は、水中からガラス原料粗溶解物を取り出した後、乾燥処理を行う。   In the solidification step, the melted glass material flowing down from the outlet is cooled and solidified. Thereby, a glass raw material crude melt is obtained. The method for cooling the molten glass raw material is not particularly limited. Usually, the molten glass raw material is poured into water and rapidly cooled. In this case, a granular glass raw material crude melt is obtained. In addition, when it cools with water, after taking out a glass raw material coarse melt from water, a drying process is performed.

続いて、本溶解工程を実施するために、ガラス原料粗溶解物を、白金、金、白金合金、金合金などの貴金属または貴金属合金製の容器、例えば、坩堝、樋状あるいはパイプ状の容器に投入して本溶解する。好ましくは白金または白金合金製の坩堝中に投入して本溶解する。その後は、必要に応じて、徐冷、プレス成形、研磨等の後工程を適宜実施することで光学ガラスを得る。なお、光学ガラスは、レンズなどの完成品であってもよく、レンズ等の完成品を製造するために用いるプリフォーム等の半製品であってもよい。   Subsequently, in order to carry out this melting step, the glass raw material crude melt is put into a container made of noble metal or noble metal alloy such as platinum, gold, platinum alloy, gold alloy, such as a crucible, bowl-shaped or pipe-shaped container. Add to the main melt. Preferably, it is put into a crucible made of platinum or a platinum alloy and completely melted. Thereafter, optical glass is obtained by appropriately performing post-processes such as slow cooling, press molding, and polishing as necessary. The optical glass may be a finished product such as a lens or a semi-finished product such as a preform used for manufacturing a finished product such as a lens.

次に、本実施形態のガラス原料粗溶解物の製造方法に用いられる原料溶解炉の具体例について、図面に基づき説明する。   Next, the specific example of the raw material melting furnace used for the manufacturing method of the glass raw material coarse melt of this embodiment is demonstrated based on drawing.

図1は、本実施形態のガラス原料粗溶解物の製造方法に用いられる原料溶解炉の一例を示す模式図であり、具体的には、原料溶解炉の主要部について示した図である。なお、図1およびその他の図において、図中に示す両矢印X方向は水平方向を意味し、両矢印Y方向は鉛直方向を意味し、矢印Y1方向は上方側、矢印Y2方向は下方側を意味する。   FIG. 1 is a schematic view showing an example of a raw material melting furnace used in the method for producing a glass raw material crude melt according to the present embodiment. Specifically, FIG. 1 shows the main part of the raw material melting furnace. In FIG. 1 and other figures, the double arrow X direction in the figure means the horizontal direction, the double arrow Y direction means the vertical direction, the arrow Y1 direction is the upper side, and the arrow Y2 direction is the lower side. means.

図1に示す原料溶解炉10は、長手方向の内径および外径が一定である1本の円筒管(筒状部材)20と、円筒管20の周囲に配置された棒状の抵抗発熱体30と、を有している。なお、図中、円筒管20および抵抗発熱体30の一部または全体を適宜囲うように配置される断熱性の壁、原料溶解炉10内や、円筒管20近傍の温度をモニターするための熱電対等の温度センサー、その他の原料溶解炉10を構成する部材については記載を省略してある。また、円筒管20内の具体的な構造についても記載を省略してある。   A raw material melting furnace 10 shown in FIG. 1 includes a cylindrical tube (tubular member) 20 having a constant inner diameter and outer diameter in the longitudinal direction, and a rod-shaped resistance heating element 30 disposed around the cylindrical tube 20. ,have. In the drawing, a heat insulating wall disposed so as to surround part or all of the cylindrical tube 20 and the resistance heating element 30, a thermoelectric for monitoring the temperature in the raw material melting furnace 10 and the vicinity of the cylindrical tube 20. The description of the temperature sensor and the other members constituting the raw material melting furnace 10 are omitted. Also, the description of the specific structure inside the cylindrical tube 20 is omitted.

ここで、円筒管20は、その中心軸Cが水平方向に対して所定の角度θを成すように傾斜して配置されている。このため、円筒管20の一方の開口部(投入口22)は、他方の開口部(流出口24)よりも上方側に位置する。また、流出口24の下方には水を満たした水槽WBが配置されている。上記傾斜角θの下限は、円筒管20中を、溶解物が流出口24側に向かって流動することが可能な角度のうち、最も小さい角度を選択することが好ましい。また、傾斜角θの上限は、円筒管20中に投入した原料のすべてが未溶解状態まま流出口24側に到達しない角度を上限とすることが好ましい。傾斜角θは例えば0度を超える範囲で適宜選択されるが、通常は、1度〜30度の範囲内とすることが好ましく、1度〜20度の範囲内とすることがより好ましく、1度〜10度の範囲内とすることがさらに好ましい。 Here, the cylindrical tube 20 is disposed so as to be inclined so that the central axis C forms a predetermined angle θ with respect to the horizontal direction. For this reason, one opening part (input port 22) of the cylindrical pipe | tube 20 is located above the other opening part (outflow port 24). A water tank WB filled with water is disposed below the outlet 24. As the lower limit of the inclination angle θ, it is preferable to select the smallest angle among the angles at which the melt can flow toward the outlet 24 in the cylindrical tube 20. Moreover, it is preferable that the upper limit of the inclination angle θ is an upper limit that does not reach the outlet 24 side in the state in which all of the raw materials charged into the cylindrical tube 20 are in an undissolved state. The inclination angle θ is appropriately selected within a range exceeding, for example, 0 °, but is usually preferably within a range of 1 ° to 30 °, more preferably within a range of 1 ° to 20 °. More preferably, the angle is within the range of 10 to 10 degrees.

ガラス原料粗溶解物の製造に際しては、不図示のガラス原料を投入口22から投入し、ガラス原料を円筒管20内にて加熱・溶解する。そして、融液状のガラス原料が流出口24から、水槽WBに満たした水中に流れ落ちる。この際、融液状のガラス原料が、水中にて、急冷・固化し、粒子状のガラス原料粗溶解物を得る。   In the production of the coarsely melted glass raw material, a glass raw material (not shown) is introduced from the inlet 22, and the glass raw material is heated and melted in the cylindrical tube 20. Then, the molten glass material flows down from the outlet 24 into the water filled in the water tank WB. At this time, the melted glass raw material is rapidly cooled and solidified in water to obtain a granular glass raw material crude melt.

なお、筒状部材20内の具体的構造としては、ガラス原料を一時的に滞留させることができるものであれば特に限定されないが、筒状部材20内にガラス原料を一時的に滞留させるための滞留部形成部材が、筒状部材20の中心軸Cに対して、略点対称を成すように配置されていることが好ましい。そして、この際、加熱・溶解工程において、筒状部材20を、その中心軸を回転軸として回転させることが好ましい。この場合、筒状部材20の回転は、連続的に実施してもよく、断続的に実施してもよい。これにより、筒状部材20内の一部分のみが、ガラス原料により著しく侵蝕されるのを防ぐことができる。これに加えて、ガラス原料を一時的に滞留させる機能を筒状部材20に付与する上で、市販の単純な形状の円筒管と、所定の形状に加工した滞留部形成部材とを用いて組み立を行うことができるので、組立作業が非常に容易である。また、滞留部形成部材の形状およびサイズ、ならびに、筒状部材20内の配置位置を適宜選択することにより、筒状部材20内におけるガラス原料の滞留の度合を容易に制御することができる。さらに、ガラス原料の加熱・溶解処理の経時的なばらつきを抑制することもできる。以下に、滞留部形成部材を筒状部材20の中心軸Cに対して点対称に配置した原料溶解炉10の具体例を図面を用いて説明する。   The specific structure in the cylindrical member 20 is not particularly limited as long as the glass raw material can be temporarily retained, but for temporarily retaining the glass raw material in the cylindrical member 20. It is preferable that the staying portion forming member is arranged so as to be substantially point-symmetric with respect to the central axis C of the cylindrical member 20. At this time, in the heating / melting step, it is preferable that the cylindrical member 20 is rotated with its central axis as the rotation axis. In this case, the rotation of the tubular member 20 may be performed continuously or intermittently. Thereby, only a part in the cylindrical member 20 can be prevented from being significantly eroded by the glass raw material. In addition to this, in order to provide the cylindrical member 20 with a function of temporarily retaining the glass raw material, the cylindrical member 20 is assembled by using a commercially available simple cylindrical tube and a retention portion forming member processed into a predetermined shape. Therefore, the assembly work is very easy. In addition, by appropriately selecting the shape and size of the staying portion forming member and the arrangement position in the tubular member 20, the degree of staying of the glass raw material in the tubular member 20 can be easily controlled. Furthermore, the time-dependent dispersion | variation in the heating / melting process of the glass raw material can also be suppressed. Below, the specific example of the raw material melting furnace 10 which has the retention part formation member arrange | positioned point-symmetrically with respect to the central axis C of the cylindrical member 20 is demonstrated using drawing.

図2は、図1に示す原料溶解炉に用いる筒状部材(円筒管)の一例を示す模式図である。ここで、図2(A)は図1に示す円筒管を、その中心軸を含む平面で切断した場合の端面図の一例を示し、図2(B)は、図2(A)に示す円筒管を流出口側から見た平面図の一例を示すものである。   FIG. 2 is a schematic diagram showing an example of a cylindrical member (cylindrical tube) used in the raw material melting furnace shown in FIG. Here, FIG. 2 (A) shows an example of an end view when the cylindrical tube shown in FIG. 1 is cut along a plane including its central axis, and FIG. 2 (B) shows the cylinder shown in FIG. 2 (A). An example of the top view which looked at the pipe | tube from the outflow port side is shown.

図2に示す円筒管20A(20)の内周には、同一の形状・サイズからなる8個のブロック状の滞留部形成部材40A(40)が固定して配置されている。図2に示す滞留部形成部材40Aは、ガラス原料Mの、円筒管20Aの長手方向に対するスムーズな移動を一時的に妨げる堰としての機能を有し、円筒管20Aの内径と同程度の外径を有する円筒管を輪切りにして得られたリング状部材を8等分するように切断する工程を経て作製された部材である。なお、切断後、滞留部形成部材40Aの形状・サイズを調整するために、必要に応じて切断面が研磨または研削されてもよい。   On the inner periphery of the cylindrical tube 20A (20) shown in FIG. 2, eight block-like staying portion forming members 40A (40) having the same shape and size are fixedly arranged. The retention part forming member 40A shown in FIG. 2 has a function as a weir that temporarily prevents smooth movement of the glass raw material M in the longitudinal direction of the cylindrical tube 20A, and has an outer diameter that is approximately the same as the inner diameter of the cylindrical tube 20A. A ring-shaped member obtained by cutting a cylindrical tube having a ring is cut into eight equal parts and is produced through a step. In addition, after cutting, in order to adjust the shape and size of the staying portion forming member 40A, the cut surface may be polished or ground as necessary.

ここで8個の滞留部形成部材40Aは、中心軸Cに対して、円筒管20Aの中央部よりやや流出口24側の位置に、円筒管20Aの内周面26に密着するように、円筒管20Aの内周方向に沿って配置されている。なお、以下の説明においては、特に説明の無い限り、中心軸Cに対する滞留部形成部材40の配置位置は、図2(A)に例示される位置に配置されるものとする。   Here, the eight staying portion forming members 40A are cylindrical so as to be in close contact with the inner peripheral surface 26 of the cylindrical tube 20A at a position slightly closer to the outlet 24 side than the central portion of the cylindrical tube 20A with respect to the central axis C. It arrange | positions along the inner peripheral direction of the pipe | tube 20A. In the following description, unless otherwise specified, the arrangement position of the staying portion forming member 40 with respect to the central axis C is assumed to be arranged at the position illustrated in FIG.

また、図2に示す例では、内周方向において互いに隣接する2つの滞留部形成部材40Aの間には、隙間W1が形成されている。この隙間長さ(周方向の長さ)は、バッチ原料の塊が通過できないような長さ、例えば0mm〜5mmの範囲内とすることが好ましく、0mm〜3mmの範囲内とすることがより好ましく、0mm〜1mmの範囲内とすることがさらに好ましい。隙間長さを上記範囲内とすることにより、固体状態のガラス原料M(S)が、滞留部Sに流れ込んだ場合、ガラス原料M(S)を滞留部Sに確実に留めることができる。これに加えて、ガラス原料M(S)が溶解して液状となったガラス原料M(L)を滞留部Sに一時的に滞留させることができると共に、滞留部Sから、流出口24側へと徐々に流出させることができる。この場合、隙間長さや、周方向に設けられる隙間W1の個数を適宜選択することにより、滞留部Sから流出口24側へと流出するガラス原料M(L)の単位時間当たりの流出量を容易に制御できる。   In the example shown in FIG. 2, a gap W1 is formed between two staying portion forming members 40A adjacent to each other in the inner circumferential direction. The gap length (the length in the circumferential direction) is preferably such that the batch raw material lump cannot pass through, for example, in the range of 0 mm to 5 mm, and more preferably in the range of 0 mm to 3 mm. More preferably, it is in the range of 0 mm to 1 mm. By setting the gap length within the above range, when the glass raw material M (S) in the solid state flows into the staying part S, the glass raw material M (S) can be reliably retained in the staying part S. In addition to this, the glass raw material M (L) in which the glass raw material M (S) has been dissolved can be temporarily retained in the retention portion S, and from the retention portion S to the outlet 24 side. And can be gradually drained. In this case, by appropriately selecting the gap length and the number of gaps W1 provided in the circumferential direction, the outflow amount per unit time of the glass raw material M (L) flowing out from the staying portion S toward the outflow port 24 can be easily obtained. Can be controlled.

なお、滞留部形成部材40を、円筒管20の内周に固定して配置する方法としては、公知の固定方法が適宜選択できる。たとえば、図2に示す例では、滞留部形成部材40Aを、内周面26に対して接着剤で接着する化学的固定方法や、滞留部形成部材40Aと内周面26とを溶接または融着する物理的固定方法が利用できる。ここで、接着剤は、この接着剤により形成された接着層が、ガラス原料の加熱温度において耐熱性を備えると共に、ガラス原料と反応またはガラス原料が溶解した融液により侵食され難いものであることが好ましい。また、固定方法としては、各種の機械的固定方法も利用できる。このような機械的固定方法としては、たとえば、内周面26に滞留部形成部材40Aを係止するための凸部を設け、この凸部を利用して滞留部形成部材40Aを固定することもできる。この場合、中心軸Cに対して凸部の投入口22が設けられた側に滞留部形成部材40Aを配置することで、滞留部形成部材40Aが、その自重により流出口24側に滑り落ちるのを防止できるように固定することができる。または、内周面26と、滞留部形成部材40Aの内周面26と対向する面にそれぞれ穴を設け、これらの穴にピンを差し込むことで内周面26に対して滞留部形成部材40Aを固定することができる。   In addition, as a method of fixing and arranging the stay part forming member 40 on the inner periphery of the cylindrical tube 20, a known fixing method can be appropriately selected. For example, in the example shown in FIG. 2, a chemical fixing method in which the staying portion forming member 40A is bonded to the inner peripheral surface 26 with an adhesive, or the staying portion forming member 40A and the inner peripheral surface 26 are welded or fused. Physical fixing methods can be used. Here, the adhesive is such that the adhesive layer formed by this adhesive has heat resistance at the heating temperature of the glass raw material and is not easily eroded by the melt with the glass raw material reacting with or dissolving the glass raw material. Is preferred. Various mechanical fixing methods can be used as the fixing method. As such a mechanical fixing method, for example, a protrusion for locking the staying portion forming member 40A is provided on the inner peripheral surface 26, and the staying portion forming member 40A is fixed using this protrusion. it can. In this case, by arranging the staying part forming member 40A on the side where the convex inlet 22 is provided with respect to the central axis C, the staying part forming member 40A slides down to the outlet 24 side due to its own weight. It can be fixed so that it can be prevented. Alternatively, holes are provided in the inner peripheral surface 26 and the surface facing the inner peripheral surface 26 of the staying portion forming member 40A, and the staying portion forming member 40A is attached to the inner peripheral surface 26 by inserting pins into these holes. Can be fixed.

次に、図2に示す円筒管20Aの投入口22からガラス原料Mを投入した場合のガラス原料Mの加熱・溶解のプロセスの一例について説明する。まず、固体状態のガラス原料M(S)を、円筒管20Aの投入口22から投入することで、投入口22近傍の内周面26上に配置する。この際、ガラス原料M(S)は加熱・溶解しながら、流出口24側へと移動する。そして、融液状態となったガラス原料M(L)は、内周面26に沿ってそのまま流出口24側へとスムーズに流れ落ちずに、一旦、滞留部形成部材40Aにより堰止められる。そして、ガラス原料M(L)は、滞留部形成部材40Aの投入口22側の近傍の領域(滞留部S)のうち、鉛直方向の最下方側近傍の領域S0に、一時的に滞留する。この滞留部Sでは、円筒管20Aの長手方向に対して、ガラス原料M(L)の水深が局所的に深くなる。ここで、滞留部Sに滞留するガラス原料M(L)は、たとえば、内周方向に互いに隣接する滞留部形成部材40Aの間の隙間W1を通過したり、および/または、融液面の上昇により滞留部形成部材40Aの内周面40AI(中心軸C側の面)を乗り越えたりすることで、徐々に流出口24側へと流れ落ちる。   Next, an example of the heating and melting process of the glass raw material M when the glass raw material M is supplied from the inlet 22 of the cylindrical tube 20A shown in FIG. 2 will be described. First, the glass raw material M (S) in a solid state is placed on the inner peripheral surface 26 in the vicinity of the charging port 22 by charging from the charging port 22 of the cylindrical tube 20A. At this time, the glass raw material M (S) moves to the outlet 24 side while being heated and melted. Then, the glass raw material M (L) in the melt state is temporarily blocked by the staying portion forming member 40 </ b> A without smoothly flowing down to the outlet 24 side as it is along the inner peripheral surface 26. Then, the glass raw material M (L) temporarily stays in the region S0 in the vicinity of the lowermost side in the vertical direction among the regions in the vicinity of the charging port 22 side (the staying portion S) of the staying portion forming member 40A. In this stay part S, the water depth of the glass raw material M (L) becomes locally deep with respect to the longitudinal direction of the cylindrical tube 20A. Here, the glass raw material M (L) staying in the staying part S passes, for example, the gap W1 between the staying part forming members 40A adjacent to each other in the inner circumferential direction and / or the rise of the melt surface. As a result of overcoming the inner peripheral surface 40AI (surface on the central axis C side) of the staying portion forming member 40A, the flow gradually falls to the outlet 24 side.

なお、ガラス原料Mは、円筒管20内への投入前の状態において、通常は粉末状の固体材料が用いられるが、粗い粒子状の固体材料、インゴット状の固体材料、または、これら材料を2種類以上混合した材料等を適宜選択して用いることもできる。また、滞留部Sに滞留するガラス原料Mは、通常は液体状であることが好ましいが、これに限定されるものではなく、たとえば、固体と液体とが混合した状態であってもよい。   As the glass raw material M, a powdery solid material is usually used in a state before being charged into the cylindrical tube 20, but a coarse particle solid material, an ingot-shaped solid material, or 2 of these materials are used. It is also possible to appropriately select and use a material mixed with two or more types. Moreover, although it is preferable that the glass raw material M which retains in the retention part S is normally a liquid form, it is not limited to this, For example, the state which the solid and the liquid mixed may be sufficient.

また、固体状態のガラス原料M(S)の円筒管20内への投入に際しては、円筒管20内に新たに投入されるガラス原料Mが、滞留部S内に滞留する液状のガラス原料M(L)の液面に覆いかぶさらないように投入されることが好ましい。新たに投入されるガラス原料M(L)が、滞留部S内に滞留する液状のガラス原料M(L)の液面を覆うように投入された場合、滞留部S内に滞留する液状のガラス原料M(L)が、滞留部形成部材40Aの上面側を乗り越えて、一時に多量に流出口24側へと流れ出すためである。この場合、ガラス原料Mを加熱・溶解するプロセスにばらつきが生じ易くなる。これに加えて、流出口24から流れ落ちる融液を水槽WB中に投入してガラス原料粗溶解物を得る場合、粒径が大きくばらつくことになる。   In addition, when the glass raw material M (S) in the solid state is charged into the cylindrical tube 20, the glass raw material M newly charged into the cylindrical tube 20 is liquid glass raw material M ( It is preferable to add so that it does not cover the liquid surface of L). When the newly introduced glass raw material M (L) is introduced so as to cover the liquid surface of the liquid glass raw material M (L) staying in the staying part S, the liquid glass staying in the staying part S This is because the raw material M (L) flows over the upper surface side of the staying portion forming member 40A and flows out to the outlet 24 side in a large amount at a time. In this case, variations tend to occur in the process of heating and melting the glass raw material M. In addition to this, when the melt flowing down from the outlet 24 is put into the water tank WB to obtain a glass raw material crude melt, the particle size greatly varies.

図3は、図1に示す原料溶解炉に用いる筒状部材(円筒管)の他の例を示す平面図であり、具体的には、図2に例示した円筒管の変形例を示した図である。ここで、図3に示す平面図は、円筒管を流出口側から見た平面図である。   FIG. 3 is a plan view showing another example of the cylindrical member (cylindrical tube) used in the raw material melting furnace shown in FIG. 1, and more specifically, a diagram showing a modification of the cylindrical tube exemplified in FIG. It is. Here, the plan view shown in FIG. 3 is a plan view of the cylindrical tube as seen from the outlet side.

図3に示す円筒管20B(20)の内周には、同一の形状・サイズからなる8個のブロック状の滞留部形成部材40B(40)が固定して配置されている。図3に示す滞留部形成部材40Bは、ガラス原料Mの、円筒管20Bの長手方向に対するスムーズな移動を一時的に妨げる堰としての機能を有し、円筒管20Bの内径と同程度の外径を有する円筒管を輪切りにして得られたリング状部材を8等分するように切断する工程を経て作製された部材である。図3に示す滞留部形成部材40Bは、図2に示す滞留部形成部材40Aと実質的に同様の形状・機能を有する部材である。8個の滞留部形成部材40Bは、円筒管20Bの内周面26に密着するように、円筒管20Bの内周方向に沿って配置され、かつ、内周方向において互いに隣接する2つの滞留部形成部材40Bの間には、隙間W2が形成されている。   On the inner periphery of the cylindrical tube 20B (20) shown in FIG. 3, eight block-like staying portion forming members 40B (40) having the same shape and size are fixedly arranged. The retention part forming member 40B shown in FIG. 3 has a function as a dam that temporarily prevents smooth movement of the glass raw material M in the longitudinal direction of the cylindrical tube 20B, and has an outer diameter that is the same as the inner diameter of the cylindrical tube 20B. A ring-shaped member obtained by cutting a cylindrical tube having a ring is cut into eight equal parts and is produced through a step. The staying part forming member 40B shown in FIG. 3 is a member having substantially the same shape and function as the staying part forming member 40A shown in FIG. The eight staying portion forming members 40B are arranged along the inner peripheral direction of the cylindrical tube 20B so as to be in close contact with the inner peripheral surface 26 of the cylindrical tube 20B, and are adjacent to each other in the inner peripheral direction. A gap W2 is formed between the forming members 40B.

また、1つのリングを構成するように円筒管20B内に配置された8個の滞留部形成部材40Bの内周側には、1つのリングを構成するように4個のブロック状部材50が固定して配置される。このブロック状部材50は、1本の円筒管を輪切りにしたリング状部材を4等分し、8個の滞留部形成部材40Bの内周側に配置できるように、適宜研削して形状を整えた部材である。   Further, four block members 50 are fixed so as to constitute one ring on the inner peripheral side of the eight staying portion forming members 40B arranged in the cylindrical tube 20B so as to constitute one ring. Arranged. The block-shaped member 50 is divided into four equal ring-shaped members obtained by slicing one cylindrical tube, and is appropriately ground so as to be arranged on the inner peripheral side of the eight staying portion forming members 40B. It is a member.

図3に示す例では、円筒管20Bの中心軸C方向のガラス原料Mや空気の自由な移動を遮断する1枚の仕切り壁を構成するように、滞留部形成部材40Bおよびブロック状部材50が円筒管20Bの内周側に配置されている。また、滞留部形成部材40Bと、ブロック状部材50との間には、間隙M1が形成されている。そして、この隙間M1は、少なくとも、固体状態のガラス原料M(S)の流動を阻害することができる程度の大きさを有する。   In the example shown in FIG. 3, the retention portion forming member 40 </ b> B and the block-shaped member 50 are configured so as to constitute one partition wall that blocks the free movement of the glass raw material M and air in the direction of the central axis C of the cylindrical tube 20 </ b> B. It arrange | positions at the inner peripheral side of the cylindrical tube 20B. Further, a gap M <b> 1 is formed between the staying part forming member 40 </ b> B and the block-like member 50. And this clearance gap M1 has a magnitude | size which can inhibit the flow of the glass raw material M (S) of a solid state at least.

ここで、単位時間当たりに、円筒管20B内に投入されるガラス原料Mの投入量が少ない場合は、滞留部形成部材40Bのみが、ガラス原料Mを円筒管20B内に一時的に滞留させる機能を発揮する。この点は、図2に示す円筒管20Aを構成する滞留部形成部材40Aも同様である。   Here, when the input amount of the glass raw material M input into the cylindrical tube 20B per unit time is small, only the retention portion forming member 40B temporarily stores the glass raw material M in the cylindrical tube 20B. Demonstrate. This also applies to the staying portion forming member 40A constituting the cylindrical tube 20A shown in FIG.

一方、図2に示す円筒管20Aでは、単位時間当たりの円筒管20A内に投入されるガラス原料Mの投入量が大きい場合には、溶解しきれなかった固体状態のガラス原料M(S)が滞留部形成部材40Aの内周面40AIを乗り越えて、流出口24側へと移動してしまうことになる。これに対して、図3に示す円筒管20Bでは、単位時間当たりの円筒管20B内に投入されるガラス原料Mの投入量が大きい場合でもブロック状部材50もガラス原料Mを円筒管20B内に一時的に滞留させる機能を発揮する。すなわち、ブロック状部材50は、ガラス原料Mの投入量が大きい場合には、ガラス原料Mの、円筒管20Bの長手方向に対するスムーズな移動を一時的に妨げる堰としての機能することができる。   On the other hand, in the cylindrical tube 20A shown in FIG. 2, when the input amount of the glass raw material M introduced into the cylindrical tube 20A per unit time is large, the solid-state glass raw material M (S) that could not be completely dissolved is obtained. It will move over the inner peripheral surface 40AI of the staying part forming member 40A and move toward the outlet 24 side. On the other hand, in the cylindrical tube 20B shown in FIG. 3, even when the input amount of the glass raw material M introduced into the cylindrical tube 20B per unit time is large, the block-shaped member 50 also puts the glass raw material M into the cylindrical tube 20B. Demonstrate temporary retention. That is, when the input amount of the glass raw material M is large, the block-shaped member 50 can function as a weir that temporarily prevents smooth movement of the glass raw material M in the longitudinal direction of the cylindrical tube 20B.

図4は、図1に示す原料溶解炉に用いる筒状部材(円筒管)の他の例を示す平面図である。ここで、図4に示す平面図は、円筒管を流出口側から見た平面図である。   4 is a plan view showing another example of a cylindrical member (cylindrical tube) used in the raw material melting furnace shown in FIG. Here, the plan view shown in FIG. 4 is a plan view of the cylindrical tube as seen from the outlet side.

図4に示す円筒管20C(20)の内周には、同一の形状・サイズからなる4個のブロック状の滞留部形成部材40C(40)が、内周方向に固定して配置されている。図4に示す滞留部形成部材40Cは、円筒管20Cの内径と同程度の外径を有する円筒管を輪切りにして得られたリング状部材を周方向に4等分するように切断する工程を経て作製された部材である。この滞留部形成部材40Cは、滞留部形成部材40Cの作製に用いたリング状部材の内周面であった面(凹面40CD)が、内周面26と対向するように円筒管20Cの内周に配置されている。このため、滞留部形成部材40Cの凹面40CDと、内周面26との間には、液状のガラス原料M(L)が容易に通過可能な間隙G2が形成される。また、内周面26の周方向に互いに隣接する2つの滞留部形成部材40Cの端面40CSと、内周面26との間にも、液状のガラス原料M(L)が容易に通過可能な間隙G3が形成される。この端面40CSは、滞留部形成部材40Cの作製に用いたリング状部材を切断した際に形成された切断面である。   On the inner periphery of the cylindrical tube 20C (20) shown in FIG. 4, four block-shaped staying portion forming members 40C (40) having the same shape and size are fixedly arranged in the inner peripheral direction. . The retaining portion forming member 40C shown in FIG. 4 is a step of cutting a ring-shaped member obtained by cutting a cylindrical tube having an outer diameter similar to the inner diameter of the cylindrical tube 20C into four equal parts in the circumferential direction. It is a member produced through the process. This staying portion forming member 40C has an inner periphery of the cylindrical tube 20C so that a surface (concave surface 40CD) that is the inner peripheral surface of the ring-shaped member used for producing the staying portion forming member 40C faces the inner peripheral surface 26. Is arranged. For this reason, a gap G2 through which the liquid glass raw material M (L) can easily pass is formed between the concave surface 40CD of the staying portion forming member 40C and the inner peripheral surface 26. Further, a gap through which the liquid glass raw material M (L) can easily pass between the end surfaces 40CS of the two staying portion forming members 40C adjacent to each other in the circumferential direction of the inner peripheral surface 26 and the inner peripheral surface 26. G3 is formed. This end surface 40CS is a cut surface formed when the ring-shaped member used for the production of the retention portion forming member 40C is cut.

図4に示す滞留部形成部材40Cは、円筒管20Cの長手方向に対して、固体状態のガラス原料M(S)のスムーズな移動を一時的に妨げる障害物として機能する。   The retention part forming member 40C shown in FIG. 4 functions as an obstacle that temporarily prevents smooth movement of the glass raw material M (S) in the solid state with respect to the longitudinal direction of the cylindrical tube 20C.

図1〜図4に例示した円筒管20、滞留部形成部材40、ブロック状部材50を構成する材料としては、ガラス原料Mに対する耐蝕性と、ガラス原料Mを加熱・溶解する際の温度に耐えうる耐熱性とを有する材料が用いられ、通常は、石英ガラスが用いられる。しかしながら、ガラス原料Mを加熱・溶解する処理を長時間に亘って実施した場合、円筒管20、滞留部形成部材40、ブロック状部材50を構成する材料は徐々に侵蝕される。このため、図2および図3に例示する滞留部形成部材40A、40Bでは、隙間W1、W2の幅が時間の経過と共に大きくなり、液状のガラス原料M(L)を堰き止める機能が低下する。この場合、円筒管20A、20B内において、ガラス原料M(L)を一時的に滞留させることが困難となる。   The materials constituting the cylindrical tube 20, the retention portion forming member 40, and the block-shaped member 50 illustrated in FIGS. 1 to 4 are resistant to the corrosion resistance to the glass raw material M and the temperature at which the glass raw material M is heated and melted. A material having high heat resistance is used, and quartz glass is usually used. However, when the process of heating and melting the glass raw material M is carried out for a long time, the materials constituting the cylindrical tube 20, the retention part forming member 40, and the block-like member 50 are gradually eroded. For this reason, in the stay part forming members 40A and 40B illustrated in FIGS. 2 and 3, the widths of the gaps W1 and W2 increase with time, and the function of blocking the liquid glass raw material M (L) is lowered. In this case, it becomes difficult to temporarily retain the glass raw material M (L) in the cylindrical tubes 20A and 20B.

このような問題の発生を防止するためには、滞留部S内に、予め、滞留部形成部材40A、40Bの堰高さ(円筒管20A、20Bの直径方向の長さ)の数分の1以下のサイズを有する複数個の阻害部材を密集して配置しておくことが好ましい。   In order to prevent the occurrence of such a problem, in the stay portion S, a fraction of the weir height (the length in the diameter direction of the cylindrical tubes 20A and 20B) of the stay portion forming members 40A and 40B is previously obtained. It is preferable that a plurality of inhibitory members having the following sizes are arranged densely.

図5は、図2(A)に示す滞留部S内に複数個の阻害部材を密集して配置した例を示す模式図である。ここで、図5(A)は、ガラス原料Mの加熱・溶解処理を開始し始めた初期の時点を示す図であり、図5(B)は、ガラス原料Mの加熱・溶解処理の開始後、滞留部形成部材40Aの侵食がある程度進行した時点を示す図である。図5に示す阻害部材60は、滞留部形成部材40Aの堰高さの数分の1〜数十分の1程度のサイズを有する部材であり、滞留部S内に密集して配置されている。なお、阻害部材60は、円筒管20、滞留部形成部材40、ブロック状部材50を構成する材料と同様の材料からなり、その形状としては、たとえば、球状、棒状、多面体状、筒状等の形状が適宜選択できる。   FIG. 5 is a schematic diagram showing an example in which a plurality of inhibitory members are densely arranged in the staying portion S shown in FIG. Here, FIG. 5A is a diagram illustrating an initial time point at which the heating / melting treatment of the glass raw material M is started, and FIG. 5B is a diagram after the heating / melting treatment of the glass raw material M is started. It is a figure which shows the time of erosion of the stay part formation member 40A progressing to some extent. The obstructing member 60 shown in FIG. 5 is a member having a size of about one-tenth to several tenths of the weir height of the staying portion forming member 40A, and is densely arranged in the staying portion S. . The inhibition member 60 is made of the same material as the material constituting the cylindrical tube 20, the staying portion forming member 40, and the block-like member 50. Examples of the shape include a spherical shape, a rod shape, a polyhedral shape, and a cylindrical shape. The shape can be selected as appropriate.

ここで、滞留部形成部材40Aの液状のガラス原料M(L)を堰き止める機能が低下し、図5(B)に示すように液面Lが大幅に低下した場合、液状のガラス原料M(L)は、阻害部材60同士の間を液状のガラス原料M(L)が流れることになる。この場合、阻害部材60が密集して配置されており、阻害部材60間の隙間は非常に小さいため、阻害部材60同士の間を液状のガラス原料M(L)の流動抵抗は非常に大きくなる。すなわち、滞留部形成部材40Aの液状のガラス原料M(L)を堰き止める機能が低下し、図5(B)に示すように液面Lが大幅に低下した場合、阻害部材60は、ガラス原料M(L)の、円筒管20Aの長手方向に対するスムーズな移動を一時的に妨げる障害物としての機能を発揮する。   Here, when the function of blocking the liquid glass raw material M (L) of the staying portion forming member 40A is reduced and the liquid level L is significantly reduced as shown in FIG. 5B, the liquid glass raw material M ( In L), the liquid glass raw material M (L) flows between the inhibition members 60. In this case, since the inhibiting members 60 are densely arranged and the gap between the inhibiting members 60 is very small, the flow resistance of the liquid glass raw material M (L) between the inhibiting members 60 becomes very large. . That is, when the function of blocking the liquid glass raw material M (L) of the staying portion forming member 40A is reduced and the liquid level L is significantly reduced as shown in FIG. The function of M (L) as an obstacle that temporarily prevents the smooth movement of the cylindrical tube 20A in the longitudinal direction is exhibited.

以上に説明した本実施形態のガラス原料粗溶解物の製造方法およびこれを用いた光学ガラスの製造方法は、リン酸塩系の光学ガラスの製造に特に好適である。リン酸塩系のガラス組成では、従来のガラス原料粗溶解物の製造方法およびこれを用いた光学ガラスの製造方法では、着色が生じ易かったが、本実施形態のガラス原料粗溶解物の製造方法およびこれを用いた光学ガラスの製造方法では、このような着色をより効果的に抑制できる。   The above-described method for producing a glass raw material crude melt and the method for producing optical glass using the same are particularly suitable for the production of phosphate-based optical glass. In the phosphate-based glass composition, the conventional glass raw material crude melt manufacturing method and the optical glass manufacturing method using the same were easily colored, but the glass raw material crude melt manufacturing method of the present embodiment And in the manufacturing method of optical glass using this, such coloring can be suppressed more effectively.

以下に、本発明を実施例を挙げて説明するが、本発明は以下の実施例にのみ限定されるものでは無い。   Hereinafter, the present invention will be described with reference to examples. However, the present invention is not limited to the following examples.

(実施例A1)
−原料溶解炉−
原料溶解炉10としては、円筒管20内が図3に示す構成からなるものを用いた。円筒管20Bおよびその内部に配置された各部材の構成材料は、全て石英ガラスからなる。ここで、円筒管20Bの寸法形状は、長さ:100cm、外径:10cm、内径:8cmであり、滞留部形成部材40Bは、厚み:5cm、外径:8cm、内径:6cmのリング状部材を、周方向に等間隔に8等分した後、円筒管20B内に配置し易いように、適宜形状を整えたものである。円筒管20B内に配置した互いに隣接する2つの滞留部形成部材40B間の隙間は約1mm前後である。また、ブロック状部材50は、滞留部形成部材40Bの作製に用いたリング状部材と同じ厚みのリング状部材を適宜切断して作製した。なお、滞留部形成部材40B、ブロック状部材50は、円筒管20Bの流出口24側から約20cmの位置に配置した。円筒管20Bの傾斜角θは3度に設定した。また、円筒管20Bの流出口24の近傍には、温度をモニターするための熱電対を配置した。
(Example A1)
-Raw material melting furnace-
As the raw material melting furnace 10, the one in which the inside of the cylindrical tube 20 has the configuration shown in FIG. 3 was used. The constituent materials of the cylindrical tube 20B and each member disposed therein are all made of quartz glass. Here, the dimensions and shape of the cylindrical tube 20B are a length: 100 cm, an outer diameter: 10 cm, an inner diameter: 8 cm, and the staying portion forming member 40B is a ring-shaped member having a thickness: 5 cm, an outer diameter: 8 cm, and an inner diameter: 6 cm. After being equally divided into eight in the circumferential direction, the shape is appropriately adjusted so that it can be easily placed in the cylindrical tube 20B. The gap between two staying portion forming members 40B arranged adjacent to each other in the cylindrical tube 20B is about 1 mm. Moreover, the block-shaped member 50 was produced by appropriately cutting a ring-shaped member having the same thickness as the ring-shaped member used for producing the staying portion forming member 40B. In addition, the retention part formation member 40B and the block-shaped member 50 were arrange | positioned in the position of about 20 cm from the outflow port 24 side of the cylindrical tube 20B. The inclination angle θ of the cylindrical tube 20B was set to 3 degrees. Further, a thermocouple for monitoring the temperature was disposed near the outlet 24 of the cylindrical tube 20B.

また、滞留部形成部材40Bにより形成される滞留部内には、外径10mm〜20mmの20〜30個のガラス片からなる阻害部材60を密集して配置した。なお阻害部材60は円筒管20と同じ材料からなる。   Further, in the staying part formed by the staying part forming member 40B, the inhibition members 60 made of 20 to 30 glass pieces having an outer diameter of 10 mm to 20 mm were densely arranged. The inhibition member 60 is made of the same material as the cylindrical tube 20.

抵抗発熱体30としては、円筒管20Bと同程度の長さを有する棒状のSiCヒータ、円筒管20Bと略平行を成すように、円筒管20Bの周囲に複数本配置した。さらに、流出口24の下方には、流出口24から流出する融液を急冷して、ガラス原料粗溶解物(カレット)を得るために、水槽WBを配置した。   A plurality of resistance heating elements 30 are arranged around the cylindrical tube 20B so as to be substantially parallel to the cylindrical SiC tube 20B and a rod-shaped SiC heater having the same length as the cylindrical tube 20B. Further, below the outflow port 24, a water tank WB was disposed in order to rapidly cool the melt flowing out from the outflow port 24 to obtain a glass raw material crude melt (cullet).

(原料)
原料から水、炭酸ガス等の加熱によりガス化する成分を除外した後の酸化物換算で、下記組成からなるリン酸塩系光学ガラス製造用の原料(ガラス原料MA)を準備した。なお、原料の調合に際しては、下記に示す各成分のうち、Pについては、正燐酸(HPO)、メタリン酸又は五酸化二燐等を用い、その他の成分については、炭酸塩、硝酸塩、酸化物等を用いた。
:17質量%
Nb:22.3質量%
Bi:43.5質量%
WO:8.6質量%
BaO:0.7質量%
:0.6質量%
TiO:2.6質量%
LiO:0.8質量%
NaO:3質量%
O:0.9質量%
合計:100質量%
Sbを外割りで0.2質量%添加
(material)
A raw material (glass raw material MA) for producing a phosphate optical glass having the following composition was prepared in terms of oxide after excluding components gasified by heating such as water and carbon dioxide from the raw material. In preparing the raw materials, among the components shown below, for P 2 O 5 , orthophosphoric acid (H 3 PO 4 ), metaphosphoric acid, phosphorous pentoxide or the like is used, and for other components, carbonic acid is used. Salts, nitrates, oxides and the like were used.
P 2 O 5 : 17% by mass
Nb 2 O 5: 22.3% by weight
Bi 2 O 5: 43.5 wt%
WO 5 : 8.6% by mass
BaO: 0.7 mass%
B 2 O 3 : 0.6% by mass
TiO 2 : 2.6% by mass
Li 2 O: 0.8% by mass
Na 2 O: 3% by mass
K 2 O: 0.9% by mass
Total: 100% by mass
Add 0.2% by mass of Sb 2 O 3

−カレットの作製−
SiCヒータにより、円筒管20Bを1100度前後まで加熱した。続いて、円筒管20Bの加熱温度を1100度に維持しつつ、投入口22側から、粉末状のガラス原料MAを投入した。なお、ガラス原料MAは、一定の時間間隔で1kgづつ投入した。また、円筒管20Bは、中心軸Cを回転軸として、原料MAを加熱、溶解する度に一定の角度づつ回転させた。そして、円筒管20B内で、融液状となったガラス原料MAを、流出口24側から流出させ、水槽WB中にて急冷し、カレットを得た。
-Production of cullet-
The cylindrical tube 20B was heated to around 1100 degrees by a SiC heater. Subsequently, while maintaining the heating temperature of the cylindrical tube 20B at 1100 degrees, the powdery glass raw material MA was charged from the inlet 22 side. The glass raw material MA was added by 1 kg at regular time intervals. The cylindrical tube 20B was rotated by a certain angle each time the raw material MA was heated and melted with the central axis C as the rotation axis. And in the cylindrical tube 20B, the glass raw material MA which became a molten liquid was flowed out from the outflow port 24 side, and rapidly cooled in the water tank WB, and the cullet was obtained.

−本溶解および光学ガラスの作製−
得られたカレット2kgを、白金坩堝に投入し、約1100度で4時間の本溶解を実施し、得られたガラスを、徐冷炉にて徐冷し、屈折率ndが2.0027、アッベ数νdが19.3の光学ガラスを得た。
-Main melting and production of optical glass-
2 kg of the obtained cullet was put into a platinum crucible, and the main melting was carried out at about 1100 degrees for 4 hours. The obtained glass was gradually cooled in a slow cooling furnace, the refractive index nd was 2.0027, the Abbe number νd Of 19.3 was obtained.

(実施例A2)
原料溶解炉10の円筒管20内の構造として、阻害部材60も併用した図3に示す構造の代わりに、図4に示す構造を採用した以外は、実施例A1で用いた原料溶解炉10と同様の構造を有する原料溶解炉10を用いた。ここで、円筒管20Cの寸法形状は、実施例A1で用いた円筒管20Bと同様である。また、滞留部形成部材40Cは、円筒管20Cと同じ材料からなるリング状部材を、周方向に等間隔に4等分した後、円筒管20C内に配置し易いように、適宜形状を整えたものである。なお、滞留部形成部材40Cは、実施例A1と同様に、円筒管20Cの流出口24側から約20cmの位置に配置した。円筒管20Cの傾斜角θは実施例A1と同様に3度に設定した。また、円筒管20Cの外周面の中央部近傍には、温度をモニターするための熱電対を配置した。
(Example A2)
The raw material melting furnace 10 used in Example A1 is the same as the structure in the cylindrical tube 20 of the raw material melting furnace 10 except that the structure shown in FIG. 4 is adopted instead of the structure shown in FIG. A raw material melting furnace 10 having a similar structure was used. Here, the dimensional shape of the cylindrical tube 20C is the same as the cylindrical tube 20B used in Example A1. In addition, the retaining portion forming member 40C was appropriately shaped so that a ring-shaped member made of the same material as that of the cylindrical tube 20C was equally divided into four in the circumferential direction so that it could be easily placed in the cylindrical tube 20C. Is. In addition, the retention part formation member 40C was arrange | positioned in the position of about 20 cm from the outflow port 24 side of the cylindrical tube 20C similarly to Example A1. The inclination angle θ of the cylindrical tube 20C was set to 3 degrees as in Example A1. In addition, a thermocouple for monitoring temperature was disposed near the center of the outer peripheral surface of the cylindrical tube 20C.

そして、実施例A1と同様にして、カレットを作製し、本溶解を行い光学ガラスを得た。   And it carried out similarly to Example A1, the cullet was produced, this melt | dissolution was performed, and the optical glass was obtained.

(比較例A1)
実施例A1で用いた原料溶解炉10において、円筒管20内から、滞留部形成部材40B、ブロック状部材50および阻害部材60を除外した原料溶解炉を用いた以外は、実施例A1と同様にしてカレットを作製し、本溶解を行い光学ガラスを得た。
(Comparative Example A1)
In the raw material melting furnace 10 used in Example A1, the same procedure as in Example A1 was used, except that the raw material melting furnace excluding the retention portion forming member 40B, the block-shaped member 50, and the inhibiting member 60 was used from the cylindrical tube 20. A cullet was prepared and melted to obtain an optical glass.

(評価)
実施例A1および実施例A2で得られた光学ガラスについては、分光光度計により、300nm〜700nmの範囲内にて、透過率の測定を行った。これら実施例A1および実施例A2の光学ガラスは、波長500nm前後から透過率が低下し、波長400nm前後で透過率がほぼゼロとなる光学特性を有していた。ここで、透過率が70%となる波長(λ70)を求めた。結果を表1に示す。なお比較例A1で得られたガラスは着色が著しく、光学ガラスとしては適さないものであった。このように実施例A1、A2、比較例B1のガラス組成は同じであるが、その製法の違いによって、実施例A1、A2では光学ガラスとして好適なガラスを得ることができたが、比較例A1のガラスは光学ガラスとしては適さない著しく着色したガラスであった。
(Evaluation)
About the optical glass obtained in Example A1 and Example A2, the transmittance | permeability was measured in the range of 300 nm-700 nm with the spectrophotometer. These optical glasses of Example A1 and Example A2 had optical characteristics such that the transmittance decreased from around 500 nm and the transmittance became almost zero at around 400 nm. Here, the wavelength (λ70) at which the transmittance is 70% was determined. The results are shown in Table 1. The glass obtained in Comparative Example A1 was extremely colored and was not suitable as an optical glass. As described above, the glass compositions of Examples A1 and A2 and Comparative Example B1 were the same, but due to the difference in the production method, in Examples A1 and A2, a glass suitable as an optical glass could be obtained, but Comparative Example A1. This glass was a highly colored glass that was not suitable as an optical glass.

Figure 2014111544
Figure 2014111544

表1に示す結果からは、実施例A1,A2の光学ガラスの方が、比較例A1の光学ガラスよりも可視光の短波長域において、より幅広い波長で光を透過し易い(着色し難しい)ことが判った。また、実施例A1の光学ガラスの方が、実施例A2の光学ガラスよりも可視光の短波長域において、より幅広い波長で光を透過し易い(着色し難しい)ことが判った。   From the results shown in Table 1, the optical glasses of Examples A1 and A2 are more likely to transmit light at a wider wavelength in the short wavelength range of visible light than the optical glass of Comparative Example A1 (it is difficult to color). I found out. Moreover, it turned out that the optical glass of Example A1 is easy to permeate | transmit light with a wider wavelength (it is difficult to color) in the short wavelength range of visible light than the optical glass of Example A2.

(実施例A3)
実施例A1において用いた円筒管20Bの代わりに、この円筒管20Bを、中心軸Cを含む平面で実質的に2分割して得られた半円筒管(図6に示す樋状部材100)を用いた。この樋状部材100は、円筒管20Bを2分割した構造を有する点を除けば、その他の寸法や構成材料は、円筒管20Bと同様である。また、円筒管20B内に配置される滞留部形成部材40Bおよびブロック状部材50についても、その配置個数を半分にして、図6に示すように、樋状部材100の内周面に配置した。そして、樋状部材100を回転させなかった点を除いて、実施例A1と同様に滞留部内に阻害部材60を配置し、実施例A1と同様の条件にてカレットを作製した。その結果、λ70は実施例A1と概ね同程度の値を示した。
(Example A3)
Instead of the cylindrical tube 20B used in Example A1, a semi-cylindrical tube (saddle-shaped member 100 shown in FIG. 6) obtained by dividing the cylindrical tube 20B into two substantially by a plane including the central axis C is used. Using. Except for the point that the bowl-shaped member 100 has a structure in which the cylindrical tube 20B is divided into two, other dimensions and constituent materials are the same as those of the cylindrical tube 20B. Further, the staying portion forming member 40B and the block-like member 50 arranged in the cylindrical tube 20B were also halved and arranged on the inner peripheral surface of the bowl-shaped member 100 as shown in FIG. Then, except that the saddle-shaped member 100 was not rotated, the inhibiting member 60 was arranged in the stay portion as in Example A1, and a cullet was produced under the same conditions as in Example A1. As a result, λ70 was almost the same value as in Example A1.

(実施例B1)
実施例B1において、ガラス原料Mとして、下記に示す下記組成からなるリン酸塩系光学ガラス製造用のガラス原料MBを使用した。そして、円筒管20Bの加熱温度を1240度に変更した以外は、実施例A1と同様にしてカレットを作製し、本溶解を行い光学ガラスを得た。
:20質量%
Nb:43質量%
BaO:19.5質量%
:3質量%
TiO:8質量%
NaO:3.5質量%
O:1質量%
ZnO:1質量%
ZrO:1質量%
合計:100質量%
Sbを外割りで0.3質量%添加
(Example B1)
In Example B1, as the glass raw material M, a glass raw material MB for producing phosphate optical glass having the following composition shown below was used. Then, except that the heating temperature of the cylindrical tube 20B was changed to 1240 degrees, a cullet was produced in the same manner as in Example A1, and was melted to obtain an optical glass.
P 2 O 5 : 20% by mass
Nb 2 O 5 : 43% by mass
BaO: 19.5 mass%
B 2 O 3 : 3% by mass
TiO 2 : 8% by mass
Na 2 O: 3.5% by mass
K 2 O: 1% by mass
ZnO: 1% by mass
ZrO 2 : 1% by mass
Total: 100% by mass
Add 0.3% by mass of Sb 2 O 3

(実施例B2)
実施例B2において、ガラス原料Mとして、ガラス原料MBを使用し、円筒管20Cの温度を実施例B1と同様に設定した以外は、実施例A2と同様にしてカレットを作製し、本溶解を行い光学ガラスを得た。
(Example B2)
In Example B2, a glass raw material MB was used as the glass raw material M, and a cullet was prepared and melted in the same manner as in Example A2, except that the temperature of the cylindrical tube 20C was set in the same manner as in Example B1. Optical glass was obtained.

(比較例B1)
比較例B1において、ガラス原料Mとして、ガラス原料MBを使用し、円筒管の温度を実施例B1と同様に設定した以外は、実施例B1と同様にしてカレットを作製し、本溶解を行い、屈折率ndが1.9236、アッベ数νdが20.9の光学ガラスを得た。
(Comparative Example B1)
In Comparative Example B1, a glass raw material MB was used as the glass raw material M, and a cullet was prepared in the same manner as in Example B1, except that the temperature of the cylindrical tube was set in the same manner as in Example B1, and this melting was performed. An optical glass having a refractive index nd of 1.9236 and an Abbe number νd of 20.9 was obtained.

(評価)
実施例B1、実施例B2および比較例B1で得られた光学ガラスについては、実施例A1の光学ガラスと同様の評価を行った。結果を表2に示す。実施例B1、実施例B2の光学ガラスは、実施例A1、実施例A2の光学ガラスよりも屈折率ndが低い分、高屈折率付与成分であるNb、TiO、BiおよびWOの合計含有量が少なく、着色が少ないガラス組成となっているが、ガラス組成が同じでも実施例B1、B2と比較例B1との間には表2に示すように着色の指標であるλ70において大きな差が見られた。
(Evaluation)
About the optical glass obtained by Example B1, Example B2, and Comparative Example B1, evaluation similar to the optical glass of Example A1 was performed. The results are shown in Table 2. In the optical glass of Example B1 and Example B2, the refractive index nd is lower than that of the optical glass of Example A1 and Example A2, and thus Nb 2 O 5 , TiO 2 , and Bi 2 O 3 that are high refractive index imparting components. And the total content of WO 3 is low and the glass composition is less colored. However, even if the glass composition is the same, there is a coloring index between Examples B1 and B2 and Comparative Example B1 as shown in Table 2. A large difference was observed at a certain λ70.

Figure 2014111544
Figure 2014111544

10 原料溶解炉
20、20A、20B、20C 円筒管(筒状部材、原料処理部材)
22 投入口
24 流出口
26 内周面
30 抵抗発熱体
40、40A、40B、40C 滞留部形成部材
40AI 内周面
50 ブロック状部材
60 阻害部材
100 半円筒管(樋状部材、原料処理部材)
10 Raw material melting furnace 20, 20A, 20B, 20C Cylindrical tube (tubular member, raw material processing member)
22 Inlet 24 Outlet 26 Inner peripheral surface 30 Resistance heating element 40, 40A, 40B, 40C Stay part forming member 40AI Inner peripheral surface 50 Block member 60 Inhibiting member 100 Semi-cylindrical tube (saddle member, raw material processing member)

Claims (4)

一方の端部に投入口を備え、他方の端部に流出口を備え、前記投入口が前記流出口よりも鉛直方向に対して上方側に位置するように配置され、かつ、筒状および樋状から選択される形状を有する原料処理部材の前記投入口から、ガラス原料を前記原料処理部材内に供給する原料供給工程と、
前記原料処理部材内に供給された前記ガラス原料を、前記投入口から、前記流出口へと移動させつつ加熱・溶解する加熱・溶解工程と、
前記流出口から流れ落ちる前記ガラス原料の融液を、冷却して、固化する固化工程と、を少なくとも経てガラス原料粗溶解物を製造し、
前記原料処理部材内の前記投入口から前記流出口側へ前記ガラス原料を移動させる際に、前記原料処理部材内において前記ガラス原料を一時的に滞留させることを特徴とするガラス原料粗溶解物の製造方法。
An inlet is provided at one end, an outlet is provided at the other end, the inlet is disposed so as to be positioned above the outlet in the vertical direction, and has a cylindrical shape and a bowl. A raw material supply step of supplying a glass raw material into the raw material processing member from the inlet of the raw material processing member having a shape selected from the shape;
A heating / melting step of heating / melting the glass raw material supplied into the raw material processing member while moving the glass raw material from the inlet to the outlet;
The glass raw material melt that flows down from the outlet is cooled and solidified to produce a glass raw material crude melt through at least a solidification step,
When the glass raw material is moved from the input port in the raw material processing member to the outlet side, the glass raw material is temporarily retained in the raw material processing member. Production method.
請求項1に記載のガラス原料粗溶解物の製造方法において、
前記ガラス原料が、Ti化合物、Nb化合物、Bi化合物、W化合物およびLa化合物から選択される少なくともいずれか1種の金属を含むことを特徴とするガラス原料粗溶解物の製造方法。
In the manufacturing method of the glass raw material coarse melt of Claim 1,
The said glass raw material contains the at least any 1 sort (s) of metal selected from Ti compound, Nb compound, Bi compound, W compound, and La compound, The manufacturing method of the glass raw material coarse melt | dissolution characterized by the above-mentioned.
請求項1または2に記載のガラス原料粗溶解物の製造方法において、
前記原料処理部材が筒状部材からなり、
前記筒状部材内に、前記ガラス原料を一時的に滞留させるための滞留部形成部材が、前記筒状部材の中心軸に対し
て、略点対称を成すように配置され、かつ、
前記加熱・溶解工程において、前記筒状部材を、その中心軸を回転軸として回転させることを特徴とするガラス原料粗溶解物の製造方法。
In the manufacturing method of the glass raw material coarse melt of Claim 1 or 2,
The raw material processing member comprises a cylindrical member,
In the cylindrical member, the retention portion forming member for temporarily retaining the glass raw material is disposed so as to be substantially point-symmetric with respect to the central axis of the cylindrical member, and
In the heating / melting step, the cylindrical member is rotated about its central axis as a rotation axis.
請求項1〜3のいずれか1つに記載のガラス原料粗溶解物の製造方法によりガラス原料粗溶解物を作製し、前記ガラス原料粗溶解物を、貴金属または貴金属合金製の容器にて本溶解する本溶解工程を少なくとも経て、光学ガラスを製造することを特徴とする光学ガラスの製造方法。   A glass raw material crude melt is produced by the method for producing a glass raw material crude melt according to any one of claims 1 to 3, and the glass raw material crude melt is finally melted in a noble metal or noble metal alloy container. An optical glass manufacturing method comprising manufacturing an optical glass through at least the main melting step.
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