Patent
Method and an installation for obtaining or recovering hydrofluoric acid
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TLDR
In this article, a method of obtaining or recovering hydrofluoric acid from metal fluorides and solutions containing such, e.g., pickling solutions, was proposed, with an overall pressure of about 1 bar keeping the vapor partial pressure in a sufficiently linear relationship with the temperature in this range.Abstract:
A method of obtaining or recovering hydrofluoric acid from metal fluorides and solutions containing such, e.g. pickling solutions. In this procedure heavy metal fluorides are brought into contact with water vapor at 200° C. to 800° C., with an overall pressure of about 1 bar keeping the vapor partial pressure in a sufficiently linear relationship with the temperature in this range at a minimum of 0.9 bar at 400° C. and at a minimum of 0.5 bar at 600° C., separating the solid reaction material from the gaseous phase while still hot and obtaining aqueous hydrofluoric acid from the latter by--preferably indirect--cooling.read more
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Process for the production or recovery of acids from metalliferous solutions of such acids
TL;DR: In this paper, the authors describe a spray-roasting of the solutions at temperatures of 200° to 500° in a reactor and subsequent absorption or condensation of the gases generated in column means at temperatures between 0° to 70° C.
Patent
Process for producing a clean hydrocarbon fuel from high calcium coal
TL;DR: In this article, a process for substantially reducing the amount of insoluble fluoride-forming species in a coal feed material comprising slurrying coal feed with a fluoride acid in the presence of an amount of fluoride-complexing species at least equal to the amount necessary to form tightly-bound complex ions with substantially all free-fluoride-ions in the slurry to produce a leached coal product and a spent leach liquor, and separating the leaching coal product from the spent leACH liquor.
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Process for obtaining treated coal and silica from coal containing fly ash
TL;DR: In this article, a process for treating mixtures of solid coal and fly ash containing metallic oxides, silicon dioxide and sulfur compounds in order to produce treated coal and substantially pure silicon dioxide is described.
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Ash removal from coal: process to avoid large quantities of hydrogen fluoride on-site
Chandrashekhar Sonwane,Draper Samuel David,Eric Stephen S.C. Kaufman,Michael David S.C. Newkirk +3 more
TL;DR: In this paper, a method and system for treating coal with hydrogen fluoride to remove fly ash and thereafter regenerating substantially all of the hydrogen fluoride used during the process (thereby significantly reducing the amount of HF on site).
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Method for the production of concentrated hydrohalogen acids and metal oxides
F Hofmann,R Lienau +1 more
TL;DR: In this article, aqueous solutions of the halides of divalent and polyvalent metals are produced by pre-concentrating the starting solution, evaporating the preconcentrated solution to a solids content of about 40 to 60 percent by weight by direct contact with a fluid heat carrier and then directly introducing the concentrate into a decomposition unit having a stationary reaction chamber wherein the metal halides are decomposed at elevated temperatures in the presence of water vapor to form the hydrogen halide and corresponding metal oxides.
Patent
Production of alumina from ores
TL;DR: In this paper, an aluminum-containing ore such as a kaolin or mont-morillonite clay is treated with a fluorine acid such as HF or H2SiF6 to produce aluminum fluoride (AlF3) which is recovered from the liquid phase of the reaction mixture by crystallization as AlF3. 3H2) crystals which are then dried and dehydrated to yield aluminum F3.