著者

木村 邦夫 陣内 和彦 諌山 幸男

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.80, no.918, pp.84-91, 1972-02-01

被引用文献数

12 11

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In view of good properties of hollow glass micro-sphere such as lightness, thermal insulating and sound arresting properties, high melting point and incombustibility and ability to increase quantity, some new composites of unparalleled characteristics are being developed by mixing them into plastics, carbon, cement, lime and its kind and metals. For instance they are now being used in diverse fields for making synthetic wood, master model, electric accessories, materials of low thermal conductivity ceramics, including aircraft materials and submarine diver-ship materials, and their demand is rapidly increasing. So, some methods to produce them have been invented already, but as the processes of them are rather complicated and the materials are expensive, the production become very expensive, too. Hereon, we authors discovered that hollow glass micro-sphere can be produced from the "Shirasu", which is acidic volcanic ejecta and one of the unutilized mineral resources distributes widely in southern Kyushu and other districts in Japan, through simple and inexpensive method. Incidentally, we will call it as "Silas Balloons". We made up an apparatus for calcining of raw material, and investigated the conditions for production of Silas Balloons, bubbling and expansive mineral component in Shirasu, the effectiveness of processing of raw material and producibility of Silas Balloons from some Shirasu produced in various districts, and measured general characteristics of Silas Balloons. And following results have been obtained. 1) Using the Shirasu as the material, it is optimum to calcine it at a temperature about 1000℃ shortly within 60 seconds. 2) Maximum size of calcining material is 300μ to obtain hollow glass microsphere. 3) It has been found that bubbling and expansive mineral component in the Shirasu is volcanic glass, and more accurately, the effective H_2O contained in it is estimated the bubbling agent. 4) Enriching the volcanic glass in the material through processing of raw material, especially through classification and magnetic separation, yield of Silas Balloons has considerably increased. 5) Some Shirasu produced in various districts would be able to be used as materials of Silas Balloons. 6) Compared with the known micro-sphere heretofore such as Microballoons of Emerson and Cuming Inc., Silas Balloons is superior to the former in its strength, melting point and hygroscopic property, though inferior to the former in its appearance.