A method for preparing electronic grade inorganic acids includes: introducing alkali metal salts into a waste acid solution containing hydrofluoric acid, nitric acid and water to obtain hydrogen fluoride vapor, and a distillation residue mixture containing nitric acid, water and the alkali metal salts; subjecting the first distillation residue mixture to evaporation treatment, and then introducing an alkali earth metal nitrate salt into the resultant nitric acid/water mixture followed by distillation treatment so as to obtain nitric acid vapor; and removing mist droplets in the hydrogen fluoride and nitric acid vapor, followed by condensation treatment and concentration adjustment so as to obtain electronic grade hydrofluoric acid and nitric acid.

Disclosed is a method of purifying a solution containing hydrofluoric acid, nitric acid and at least one silicon impurity by treating the solution with at least one reverse osmosis membrane. According to the method of the present invention, silicon impurities contained in the solution containing hydrofluoric acid and nitric acid can be selectively removed or reduced. This method can be advantageously used in the photovoltaic industry or in the battery component industry.

A method of recycling mixtures of hydrochloric and hydrofluoric acid. In particular, a method of recycling hydrofluoric acid and boron fluoride mixtures. A process for upgrading mixtures of fluoroboron compounds contaminated with chlorides as an aqueous solution of boron fluoride hydrates, including a step of vacuum distillation. Also, a method of producing gaseous boron trifluoride.

This invention provides a method for stably producing 2,3,3,3-tetrafluoropropene for a long period of time wherein unreacted materials are reused after distillation without liquid-liquid separation to suppress catalyst deactivation. The method for producing 2,3,3,3-tetrafluoropropene comprises the step of reacting 1233xf or like chloropropene with hydrogen fluoride in the presence of a catalyst, the step of subjecting the reaction mixture obtained in the above step to distillation to separate the mixture into a first stream comprising 2,3,3,3-tetrafluoropropene as a main component and a second stream comprising unreacted hydrogen fluoride and organic matter containing unreacted chloropropene as main components, and the step of recycling the second stream to the above reaction, the distillation being performed under conditions in which the unreacted hydrogen fluoride and the organic matter containing the unreacted chloropropene do not undergo liquid-liquid separation at a portion of a distillation column from which the second stream is withdrawn.

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 technique for obtaining anhydrous hydrogen fluoride (AHF) from an aqueous solution of hexafluorosilicic acid (HSA). A method for obtaining hydrogen fluoride from an aqueous solution of hexafluorosilicic acid can include mixing a solution of hexafluorosilicic acid with a sulfuric acid solution, desorbing the hydrogen fluoride from the resultant solution of sulfuric acid, treating it with sulfuric acid and condensing the anhydrous hydrogen fluoride from unabsorbed gasses. The generated gaseous products are then burned in a fire of hydrogen-containing fuel and an oxygen-containing oxidant, yielding a solid silicon dioxide. The remaining products are cooled and yield condensed anhydrous hydrogen fluoride.

This patent relates to the mineral waste treatment of the phosphate chemical industry, namely, treatments of hexafluorosilicic acid solutions formed specifically during the process of producing phosphoric acid with hydrogen fluoride. The method for obtaining hydrogen fluoride from hexafluorosilicic acid includes neutralizing the HSA solution with an alkaline agent, yielding a solid salt from the suspension, processing the salt in a fire of a hydrogen-containing fuel and an oxygen-containing oxidant, cooling the combustion products, eliminating the silicon dioxide from these products, condensing the hydrogen fluoride and water, and subsequently extracting the hydrogen fluoride.

Provided are a method for treating sulfur hexafluoride and an apparatus for collecting and treating by-products. The method for treating sulfur hexafluoride, and the apparatus for collecting and treating by-products according to the present invention are a significantly effective method and apparatus capable of safely treating sulfur hexafluoride at low cost.

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.

Methods of converting a variety of fluorinated materials into anhydrous hydrogen fluoride are described. The methods include thermally decomposing the fluorinated materials into a gaseous effluent comprising hydrogen fluoride and carbon dioxide. This gaseous effluent is then treated with carbon at a temperature of at least 830 C., converting the carbon dioxide to carbon monoxide (CO) and producing a gaseous product comprising the hydrogen fluoride, which can be condensed to generate anhydrous hydrogen fluoride. These methods can also be used to convert water contained in the gaseous effluent into hydrogen.