An organic binder system is mixed with molding material for sand casting in the metals industry. The organic binder system has three parts, the first two of which are conventional and are used in the cold box or no bake process. The third part, which is combined with the first two parts at the time of use, contains at least an alkyl silicate and, optionally, a bipodal aminosilane. In some embodiments, an amount of hydrofluoric acid is included in one or both of the first two parts. Use of the organic binder system provides improved tensile strength in the mold, especially in high relative humidity.

A method for separating halocarbons and, in particular, a method for separating (Z)-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd(Z), or simply 1233zd(Z)) and 1-chloro-1,3,3,3-tetrafluoropropane (HCFC-244fa, or simply 244fa) via distillation by adding a third component, hydrogen fluoride (HF), forming a binary azeotrope of 1233zd(Z) and HF. The binary 1233zd(Z)/HF azeotrope may then be recovered from the distillation column as an overhead stream which includes only a relatively minor amount of 244fa, while the 244fa may be recovered from the distillation column as a bottoms stream which includes only relatively minor amounts of 1233zd(Z) and HF.

A process for purification of hydrofluoric acid reduces the content of heavy metals, including arsenic, to values lower than five parts per million, without using any chemicals and with an integrated design of hot and cold streams that provide low energy consumption. The process allows extraction of heavy metals, especially arsenic, with minimal waste generation and while maintaining an original oxidation state, which for the case of arsenic is +3, so that the residue can he converted into a product with commercial value, such as arsenious acid. The process includes operation of four systems, namely, a hydrofluoric acid purification system, an arsenic concentration system, a hot water system, and a cold water system. The extraction of heavy metals is performed by synchronized operations of these four systems.

An azeotropic or quasi-azeotropic composition including hydrogen fluoride, 3,3,3-trifluoro-2-chloropropene and one or more (hydro)halogen-carbon compounds including between 1 and 3 carbon atoms. Also an azeotropic or quasi-azeotropic composition including hydrogen fluoride, 3,3,3-trifluoro-2-chloropropene, and one or more compounds selected from among 1,3,3,3-tetrafluoropropene, 1,1,1,2,2-pentafluoropropane, 2,3,3,3-tetrafluoropropene, 3,3,3-trifluoropropene, E-3,3,3-trifluoro-1-chloropropene, trifluoropropyne, 1,1,3,3-pentafluoropropane, 1,1,1,3,3-pentafluoropropane, 1,1,1,3,3-pentafluoropropene, 1,1,1,2,3-pentafluoropropene and 2-chloro,1,1,1,2-1 tetrafluoropropane.

In one embodiment, an anhydrous hydrogen fluoride generator vessel (also referred to herein as the AHF generator vessel) is provided. In several embodiments, an AHF generator vessel may include a container assembly, one or more shelves, and a center pipe assembly. The container assembly may include a lid assembly that may be removably coupled to the wall, and one or more feet. The center pipe assembly may include a base adapter, a center pipe, and a bottom adapter. In one embodiment, sodium bifluoride is loaded onto the one or more shelves which are positioned perpendicular to the center pipe and stacked upon one another. An external heat source may provide the heat to the vessel to thermally degrade the sodium bifluoride into HF and sodium fluoride (NaF). In various embodiments, the HF may be carried by a carrier gas out of the AHF generator vessel via the lid assembly.

A gas nozzle (100), a gas reaction device (10) and a gas hydrolysis reaction method. A plurality of fuel gas channels (116) are provided on a side wall of a nozzle cavity (110) of the gas nozzle (100); the plurality of fuel gas channels (116) are arranged around the side wall of the nozzle cavity (110); a mixed gas introduced from a nozzle inlet (112) is surrounded by a fuel gas (21) introduced from the plurality of fuel gas channels (116); and the fuel gas channels (116) are inclined towards a nozzle outlet (114), and the fuel gas channels (116) are further inclined in the same clockwise direction. In this way, the fuel gas (21) introduced from the plurality of fuel gas channels (116) forms a downwardly conical spiral flame, and a flame formed by the mixed gas introduced from the nozzle inlet (112) is wrapped therein and sprayed out from the nozzle outlet (114).

The present invention provides a novel method for producing hydrogen fluoride which can suppress the occurrence of the pasty state over the whole process of producing hydrogen fluoride, reduce the problem of corrosion caused by sulfuric acid, and improve energy efficiency of the process. A method for producing hydrogen fluoride by reacting calcium fluoride and sulfuric acid comprises: (a) mixing and reacting calcium fluoride and sulfuric acid such that a mixture comprising calcium fluoride particles and sulfuric acid substantially maintains a form of particulate to obtain hydrogen fluoride while supplying sulfuric acid to the calcium fluoride particles at a flow rate of 0.002 to 1 mol/min relative to 1 mol of calcium fluoride to such an amount that a molar ratio of sulfuric acid/calcium fluoride is 0.9 to 1.1.

Provided herein are methods and systems for using heat from acid generation, comprising: an acid generating system configured to generate heat and an acid: a wet solids generating system configured to: dissolve a first calcium source in the acid; and precipitate a second calcium source using the dissolved first calcium source to generate a wet solid; and a dryer configured to dry the wet solid using the heat from the acid generating system.

The present invention provides a novel method for producing hydrogen fluoride, which is capable of using various calcium fluoride sources and preventing a second pasty state from occurring, effectively. In a method for producing hydrogen fluoride by reacting calcium fluoride with sulfuric acid, following steps are conducted: (a) a step for mixing and reacting calcium fluoride particles having an average particle diameter of 1-40 m with sulfuric acid at a sulfuric acid/calcium fluoride molar ratio of 0.9-1.1 under a temperature of 0-70 C. to obtain a solid-state reaction mixture; and (b) a step for heating the solid-state reaction mixture to a temperature of 100-200 C. to react with itself, and thereby producing hydrogen fluoride in a gas phase.

Provided is a preparation method and use method of a material for deep purification of HF electronic gas. A metal fluoride-loaded activated carbon material AC/MFx.Math.nH.sub.2O is prepared, and a mixed gas flow of carbonyl fluoride and high-purity nitrogen is used to deeply dehydrate the material to obtain the material for deep purification of HF electronic gas AC/MFx. This kind of material has fluoride that can form crystal water to form hydrated metal fluoride, and has strong water absorption properties. Moreover, the anhydrous fluoride and activated carbon do not have to face the problem of being corroded by HF, and the collapse of framework structure and the secondary pollution to HF from reaction products would not be caused. The material has the advantages of high purity and extremely low moisture content when being used for efficiently removing moisture in HF.