Disclosed is a purification method for removing a metal component from a fluorine compound gas containing hydrogen fluoride and a metal component. This method includes a removing step for removing the hydrogen fluoride and the metal component therefrom by bringing the fluorine compound gas into contact with a solid metal fluoride to adsorb the hydrogen fluoride and the metal component on the metal fluoride. It is preferable for the fluorine compound gas to contain at least one kind selected from the group consisting of CIF, CIF.sub.3, IF.sub.5, IF.sub.7, BrF.sub.3, BrF.sub.5, NF.sub.3, WF.sub.6, SiF.sub.4, CF.sub.4, SF.sub.6 and BF.sub.3. It is also preferable for the metal fluoride to be an alkali metal fluoride or an alkali earth metal fluoride. Surprisingly, the presence of hydrogen fluoride in a fluorine compound gas makes it possible to remove a metal component therefrom as an impurity as a result of adsorption thereof by a metal fluoride.

Disclosed is a production device and production method of electronic grade hydrofluoric acid. The method includes vaporizing the raw material industrial anhydrous hydrogen fluoride by an evaporator, transporting the vaporized hydrogen fluoride to a purification tower, obtaining a high purity hydrogen fluoride gas through rectification, transporting the high purity hydrogen fluoride gas to an absorption tower for absorption by a certain concentration of hydrofluoric acid in the liquid phase, obtaining the crude electronic grade hydrofluoric acid, and obtaining the electronic grade hydrofluoric acid product through ultrapure filtration. The disclosure overcomes the technical problems of small yield and low purity of the prior art. The production process meets the requirements of environmental protection. The disclosure is suitable for industrialized large-scale production.

A method of neutralizing condensate from a gas flow subject to a combustion oxygen removal process passing through a number of cooling steps post combustion includes: providing a supply of water to the gas flow prior to a particular cooling step of the number of cooling steps; collecting an aqueous condensate solution from the gas flow prior to the particular cooling step; and providing a supply of a neutralizing agent to the aqueous condensate solution.

Calcium hydroxide-containing compositions can be manufactured by slaking quicklime, and subsequently drying and milling the slaked product. The resulting calcium hydroxide-containing composition can have a size, steepness, pore volume, and/or other features that render the compositions suitable for treatment of exhaust gases and/or removal of contaminants. In some embodiments, the calcium hydroxide-containing compositions can include a D.sub.10 from about 0.5 microns to about 4 microns, a D.sub.90 less than about 30 microns, and a ratio of D.sub.90 to D.sub.10 from about 8 to about 20, wherein individual particles include a surface area greater than or equal to about 25 m.sup.2/g.

A gas chamber supply system includes a gas source configured to fluidly connect to a gas chamber and to supply a gas mixture to the gas chamber, the gas source including: a pre-prepared gas supply including a gas mixture, the gas mixture including a plurality of gas components and lacking a halogen; a recycled gas supply including the gas mixture; and a fluid flow switch connected to the pre-prepared gas supply and to the recycled gas supply. The gas chamber supply also includes a control system configured to: determine if the relative concentration between the gas components within the recycled gas supply is within an acceptable range; and provide a signal to the fluid flow switch to thereby select one of the pre-prepared gas supply and the recycled gas supply to as the gas source based on the determination.

An air filter including a filter support that supports polymeric sorbent particles. The polymeric sorbent is the reaction product of a divinylbenzene/maleic anhydride precursor polymeric material with a nitrogen-containing compound. The air filter may be used for capturing e.g. reactive gases.

Device (10) for injecting powders into a furnace pipe (500), comprising a chamber (230) connected to a peripheral pipe (220) and, on the other hand, to the said furnace pipe via the said peripheral pipe (220), which comprises a first part (221) of diameter DP1, and a second part (222) of diameter DP2, having a downstream end (222a) and intended to be in communication with the furnace pipe, and a powder conveying pipe (120) which has a diameter DT and a downstream end (121), characterized in that the second part of the peripheral pipe has a length Lthe diameter (DP2) of the second part of the peripheral pipe, and in that the diameter (DT) and the diameter (DP2) are connected by the relationship 0<DP2DT< DT.

A method and device for waste gas dedusting and a dedusting agent used in the method. A dust-containing waste gas (1) and an organic dedusting agent (4) are introduced into a dedusting tower (3), respectively, and make contact with each other in the tower; at least part of the water vapor in the dust-containing waste gas (1) is condensed, and the organic dedusting agent (4) and the condensed water adsorb solid particles, acidic pollutants, organic pollutants and/or heavy metal compounds in the dust-containing waste gas; and the resulting purified gas (2) is emptied out or subjected to a subsequent process. The organic dedusting agent (4) comprises a non-toxic and high boiling point organic solvent composition, being two or more selected from cooking oil, silicone oil, modified silicone oil, liquid-state asphalt oil, tung tree seed oil, liquid-state paraffin wax oil, mineral oil, palm oil and waste cooking oil.

A process for purifying a feed gas stream containing at least 90% of CO.sub.2, at least 20% RH and at least one impurity chosen from chlorinated, sulfur-bearing, nitrated or fluorinated compounds is provided. The process includes a) subjecting the feed gas stream to catalytic oxidation producing a stream containing at least one of HCl, NOx, SOx or hydrofluoric acid; b) maintaining the temperature of the gas stream above the highest value between the dew points of water and the acid(s) contained in the gas; c) removing at least a part of the acid impurities by bringing the gas stream into contact with a corrosion-resistant heat exchanger to condense the acid compounds while regulating the temperature of the gas stream exiting below the dew point of water; and d) separating the acid condensates with a corrosion-resistant separator in such a way as to produce a CO.sub.2-enriched gas stream.

Calcium hydroxide-containing compositions can be manufactured by slaking quicklime, and subsequently drying and milling the slaked product. The resulting calcium hydroxide-containing composition can have a size, steepness, pore volume, and/or other features that render the compositions suitable for treatment of exhaust gases and/or removal of contaminants. In some embodiments, the calcium hydroxide-containing compositions can include a D.sub.10 from about 0.5 microns to about 4 microns, a D.sub.90 less than about 30 microns, and a ratio of D.sub.90 to D.sub.10 from about 8 to about 20, wherein individual particles include a surface area greater than or equal to about 25 m.sup.2/g.