Diatomaceous earth (diatomaceous earth)

Japanese: ケイ藻土(珪藻土) - けいそうど（英語表記）diatomite

It is a siliceous sedimentary rock formed by the deposition of diatom remains on the bottom of oceans and lakes, and contains clay, volcanic ash, organic matter, etc. Unconsolidated diatomaceous earth is called diatomaceous mud. Diatomaceous earth is used as an absorbent, adsorbent, degreasing material, filter material, insulating brick material, cement admixture, filler, abrasive, etc. Since diatomaceous earth contains impurities, it is refined according to its intended use. In general, elutriation is used to remove impurities such as sand, calcination is used to remove organic matter, deferrication is used to remove iron, and acid treatment or calcination with water glass is used to whiten (decolorize) it for filling rubber, paper, and pigments.

Source: Heibonsha World Encyclopedia, 2nd Edition Information

Japanese:

ケイ藻の遺骸が，海底，湖沼底などに沈積して形成されたケイ質堆積岩で，粘土，火山灰，有機物などを含む。未固結のものはケイ藻軟泥といわれる。ケイ藻土は，吸収材，吸着材，脱脂材，ろ過材，断熱煉瓦材，セメント混和材，充てん材，研磨材などに用いられる。ケイ藻土は不純物を含むので，使用目的に合った精製処理が行われる。一般に，砂などの不純物の除去には水簸（すいひ）処理，有機物除去には煆焼（かしよう）処理，鉄分除去には脱鉄処理，ゴム，紙，顔料の充てん用の白色化(脱色化)には酸処理あるいは水ガラスと混合しての焼成処理を行う。

出典　株式会社平凡社世界大百科事典第２版について　情報

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