To provide a method for producing clean treated coal and silicon dioxide by efficiently separating coal and fly ash comprising a metal oxide, silicon dioxide and a sulfur compound.
The method for producing treated coal 38 and practically pure silicon dioxide 45 comprises the following processes: [1] a process for reacting a mixture 23 of coal and fly ash with an aqueous solution of hydrogen fluoride to generate a liquid flow 27 including silicon fluoride and a metal fluoride and a solid flow 29 including unreacted coal and a sulfur compound; [2] a process for reacting the sulfur compound with a metal nitrate dissolved in water to generate an aqueous solution of a nitrate ion, a metal ion and a sulfur ion; [3] a process for separating an aqueous solution of a nitrate ion, a sulfur ion and a metal ion from solid coal 38; [4] a process for cleansing the treated coal 38; and [5] a process for reacting silicon fluoride and the metal fluoride with a metal nitrate in an aqueous mixture to generate solid silicon dioxide 45 and then separating the solid silicon dioxide 45 from an aqueous mixture.
COPYRIGHT: (C)2011,JPO&INPIT
Hirokazu Ogura
Toshihisa Kurokawa
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