| 摘要 |
PCT No. PCT/DE96/01693 Sec. 371 Date Jun. 27, 1997 Sec. 102(e) Date Jun. 27, 1997 PCT Filed Sep. 10, 1996 PCT Pub. No. WO97/10410 PCT Pub. Date Mar. 20, 1997The description relates to a process and a device for drilling holes in hard rocks like granite, in which the rock to be drilled is exposed to a flame produced by gaseous hydrogen and fluorine together and the reaction products produced by the flame are taken out of the drilling with the aid of a sucked aqueous liquid. In order to be able to implement the process economically while preventing the formation of toxic and corrosive reaction products, the aqueous liquid used to remove the reaction products formed is a lye, e.g. a sodium hydroxide solution, in which the excess hydrogen fluorine formed during the combustion of hydrogen and fluorine is converted into a non-toxic fluoride, e.g. sodium fluoride, while at the same time the other reaction products are converted into water-soluble silicates, aluminates and alkaline fluorides. In order to recover the very expensive gaseous fluorine used, the dissolved sodium fluoride formed by chemical reaction is converted into insoluble calcium fluoride with the aid of calcium oxide or calcium hydroxide and subsequently electrolysed.
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