Disclosed is a method of regenerating a nitric and hydrofluoric acid bath contained in a machining vessel, the method including, when the etching bath is spent, performing steps of: transferring a portion of the spent etching bath, referred to as the spent solution, from the machining vessel into a reactor; adding NaF and NaNO.sub.3 to the spent solution, to form HF, HNO.sub.3, and Na.sub.2TiF.sub.6; separating the resulting precipitate from the supernatant; transferring the supernatant, which is a regenerated solution, into a tank; measuring the concentrations of HF, of HNO.sub.3, and of dissolved titanium in the tank and in the machining vessel; and determining the volume of regenerated solution that can be added to the spent etching bath to obtain a regenerated bath in which the concentrations of HF, of HNO.sub.3, and of dissolved titanium lie in acceptable concentration ranges, and transferring the regenerated solution into the machining vessel.

A process for producing a main (hydro)halocarbon compound, including the formation of a mixture of compounds including hydrogen fluoride, Z-3,3,3-trifluoro-1-chloropropene and one or more other (hydro)halocarbon compounds, distillation of this mixture making it possible to collect, firstly, an azeotropic composition, and, secondly, at least one of the compounds of the mixture. The (hydro) halocarbon compounds are preferably selected among tetrachlorofluoropropanes, trichlorodifluoropropanes, dichlorotrifluoropropanes, chlorotetrafluoropropanes, pentafluoropropanes, dichlorodifluoropropenes, chlorotrifluoropropenes and tetrafluoropropenes.

Embodiments of the invention relate to a process for removing fluoride from a solution or suspension containing zinc, in particular a solution of zinc sulfate, a defluoridated solution of zinc sulfate obtainable by such a process, its use as well as processes for producing zinc and hydrogen fluoride or hydrofluoric acid. The process for removing fluoride comprises (i) providing a solution or suspension A containing zinc, wherein the solution or suspension A containing zinc further contains fluoride ions; (ii) adding a solution B containing a dissolved salt of a rare earth element to the solution or suspension A containing zinc, wherein a solid comprising a rare earth element fluoride and a solution C containing zinc are formed; and (iii) separating the solid from the solution C containing zinc, wherein the solution C containing zinc has a lower concentration of fluoride ions than the solution or suspension A containing zinc.

Provided is disclosure for embodiments providing delivery of chemicals for conditioning a brush offline, where the brush is not coupled to a machine that makes use of the brush to clean a surface of an object.

Clean, safe and efficient methods and systems for utilizing thermolysis methods to process and recycle various waste sources containing per- and polyfluoroalkyl substances to safely remove fluorine and other hazardous materials are provided. The methods and systems beneficially convert waste sources into a Clean Fuel Gas and Char source providing safe, efficient, and cost-effective alternatives to the current buildup of such waste sources. Methods utilizing a multicomponent, energy-assisted, chemical reaction are provided.

The present disclosure provides a novel azeotropic or azeotrope-like composition comprising hydrogen fluoride and 1,1,2-trifluoroethane (HFC-143), 1-chloro-2, 2-difluoroethane (HCFC-142), or 1,2-dichloro-1-fluoroethane (HCFC-141); and a separation method using the composition.

An azeotropic or azeotrope-like composition comprising hydrogen fluoride and HFC-143. An azeotropic or azeotrope-like composition comprising hydrogen fluoride and HCFC-142. An azeotropic or azeotrope-like composition comprising hydrogen fluoride and HCFC-141. A separation method of a composition comprising hydrogen fluoride and at least one member selected from the group consisting of HFC-143, HCFC-142, and HCFC-141.

Reactions are disclosed in which phosphine and hydrogen fluoride are reacted to produce a phosphorus pentafluoride containing gas according the stoichiometry:

PH.sub.3+4F.sub.2.fwdarw.PF.sub.5+3HF

Further reaction using the phosphorus pentafluoride to produce lithium hexafluorophosphate are also disclosed.

A process for reducing the concentration of one or more arsenic-containing compounds in an aqueous solution comprising at least one fluoroacid, which process comprises: (i) contacting the aqueous solution with an oxidising agent to produce one or more Asv-containing compounds; and (ii) removal of precipitated arsenic-containing compounds; wherein the process comprises a step (iii) the addition of an aqueous alkali solution or slurry, which may take place after step (i) and before step (ii) or after step (ii).

Embodiments of the invention provide a method for atomic layer etching (ALE) of a substrate. According to one embodiment, the method includes providing a substrate, and exposing the substrate to hydrogen fluoride (HF) gas and a boron-containing gas to etch the substrate. According to another embodiment, the method includes providing a substrate containing a metal oxide film, exposing the substrate to HF gas to form a fluorinated surface layer on the metal oxide film, and exposing the substrate to a boron-containing gas to remove the fluorinated surface layer from the metal oxide film. The exposures may be repeated at least once to further etch the metal oxide film.

An inhibited hydrofluoric acid aqueous composition, said composition comprising: hydrofluoric acid in solution; and an alkanolamine; wherein said alkanolamine and hydrofluoric acid are present in a molar ratio of at least 1:1.