Abstract: Disclosed is a process for the manufacture of 1234yf from 1,1,2,3-tetrachloropropene, abbreviated herein as “TCP,” in three integrated steps: (a) the R-1 hydrofluorination of TCP to form 1233xf in the vapor phase; (b) the R-2 hydrofluorination of 1233xf to form 244bb in either the liquid phase or in the liquid phase followed by the vapor phase; and (c) the R-3 dehydrochlorination of the 244bb in either the liquid or the vapor phase to produce 1234yf; wherein the vapor phase hydrofluorination of TCP in step (a) is carried out at a higher pressure than the liquid phase hydrofluorination of 1233xf; and wherein the HC1 generated during these steps is scrubbed with water to form an acid solution and the organic components are scrubbed with a caustic solution and then dried before further processing.

Abstract: 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.

Abstract: Aqueous leachant compositions and processes for using the same comprising: (a) providing a metal-containing compound; and (b) subjecting the metal-containing compound to an acid digestion comprising contacting the metal-containing compound with an aqueous leachant; wherein the aqueous leachant comprises a mixture selected from the group consisting of: (i) sulfuric acid and one or more alkanesulfonic acids having alkane moieties selected from the group consisting of propyl, ethyl and methyl groups, at a weight ratio of alkanesulfonic acid to sulfuric acid of 1:1000 to 1:1; (ii) sulfuric acid and one or more salts of alkanesulfonic acids having alkane moieties selected from the group consisting of propyl, ethyl and methyl groups, at a weight ratio of salt of alkanesulfonic acid to sulfuric acid of 1:9 to 1:99.

Abstract: Provided is a method for regulating the concentration of water in the acid feed stream in a process for the production of HF by the reaction with a fluorine containing material, the method comprising: (a) providing an acid feed stream comprising bound water and free water; (b) estimating the concentration of bound water and free water in the acid feed stream by providing a probe in said feed stream; and (c) adjusting the concentration of free water in said process stream based on said estimating step.

Abstract: As to a reactor which is used in a process for producing hydrogen fluoride through a reaction of fluorite with sulfuric acid, and which comprises means for applying a shearing force to a content therein between the means and an inner surface thereof, a metal material is used for at least a portion of a part of the means which part is opposed to the inner surface, the metal material comprising tungsten carbide and a material comprising at least one element, or an alloy comprising two or more elements, selected from the group consisting of nickel, chromium, cobalt, iron, tungsten and carbon, the metal material comprising 30 to 90% by weight of tungsten carbide. Thereby, it becomes possible to reduce the wear of an edge of the means for applying the shearing force to the content (the reaction mixture) between the means and the inner surface.

Abstract: The present invention relates to compositions, kits and processes for the brightening of metal surfaces by the application of the chemical compositions. These compositions act to release hydrofluoric acid as a brightening agent. The solutions are preferably mixed during application of the brightening composition to a metal surface by mixing the solutions immediately prior to or even during application of the solution. This can be readily accomplished by mixing two solutions, one having a fluoride source and the other having a strong acid to release hydrofluoric acid from the fluoride source, the mixing occurring immediately before spray application, during spraying, or immediately after spraying of the two solutions. Mixing may be done on-site, which means that mixing is performed at the site of use, usually on the same day of use or even within a few (less than 10) minutes of use.

Abstract: The invention relates to a novel process for preparing hydrogen fluoride in a uniformly high conversion at a high space-time yield with minimal energy consumption by reaction of fluorspar with sulfuric acid in a rotary tube furnace, in which the furnace is divided into three equal-sized zones, each of which is heated indirectly by means of from 1 to 12 independent combustion chambers, there being a temperature gradient between the zones such that the first zone has the highest temperature and the third zone has the lowest temperature.

Abstract: The present invention relates to compositions, kits and processes for the brightening of metal surfaces by the application of the chemical compositions. These compositions act to release hydrofluoric acid as a brightening agent. The solutions are preferably mixed during application of the brightening composition to a metal surface by mixing the solutions immediately prior to or even during application of the solution. This can be readily accomplished by mixing two solutions, one having a fluoride source and the other having a strong acid to release hydrofluoric acid from the fluoride source, the mixing occurring immediately before spray application, during spraying, or immediately after spraying of the two solutions. Mixing may be done on-site, which means that mixing is performed at the site of use, usually on the same day of use or even within a few (less than 10) minutes of use.

Abstract: A method of treating a surface of a metal is provided. A source of fluoride ion is mixed with a source of acid to form hydrofluoric acid and, when applied to a metal surface to be treated, the hydrofluoric acid acts as a brightening agent.

Abstract: A method of quickly and safely determining the component concentrations of a three-component mixture comprising substantially sulfuric acid, hydrogen fluoride and water, which comprises measuring at least one set of three physical quantities of (1) temperature, (2) ultrasonic wave propagation velocity and (3) electric conductivity or viscosity of the three-component mixture and converting the obtained values to the component concentrations on the basis of a working curve representing the relationship between each component concentration of the three-component mixture and the three physical quantities; and a method of continuous production of hydrogen fluoride for controlling a water concentration in the reaction system by using this method.

Abstract: The invention relates to a novel process for preparing hydrogen fluoride in a uniformly high conversion at a high space-time yield with minimal energy consumption by reaction of fluorspar with sulfuric acid in a rotary tube furnace, in which the furnace is divided into three equal-sized zones, each of which is heated indirectly by means of from 1 to 12 independent combustion chambers, there being a temperature gradient between the zones such that the first zone has the highest temperature and the third zone has the lowest temperature.

Abstract: Flux residues from aluminium soldering fluxes composed of alkali metal metallates, especially fluoroaluminates of the alkali metals, in particular potassium and cesium, can be recycled by adding them to the reaction mixture used for the production of hydrogen fluoride from fluorspar and sulfuric acid or oleum. In this way the fluorine content of the flux residues becomes reusable, and the anhydrite which is produced can advantageously be used for conventional purposes.

Abstract: A method is provided wherein the equilibrium HF concentration in the mixture of HF, sulfuric acid and water fed to an HF reaction furnace is greatly reduced by injecting a controlled amount of steam into an HF-removal process wherein the sulfuric acid mixture is also contacted with the hot HF gas leaving the HF reaction furnace. Reducing the HF concentration in this manner significantly improves furnace performance.The purpose of injecting steam is to adjust the water content of the mixture to the optimum value (about 12.5 weight percent) for HF removal, as well as to supply the heat required for HF removal without the need for an indirect heat exchanger.An additional advantage to this method is that since direct steam injection adds water to the process, in order to keep the furnace feed acid water concentration at the desirable level of less than 1%, oleum or SO.sub.3 must be added to react with the excess water. Since the reaction of water and SO.sub.

Abstract: A process for preparing hydrogen fluoride, which comprises (i) reacting calcium fluoride with sulfuric acid to produce a gypsum and a gas containing hydrogen fluoride, (ii) separating hydrogen fluoride from said gas containing hydrogen fluoride, (iii) absorbing said hydrogen fluoride-separated gas with water to obtain an aqueous solution containing hydrogen fluoride and silicofluoric acid, (iv) reacting calcium carbonate with said aqueous solution to obtain a suspension containing silicic acid and calcium fluoride, (v) adding an alkaline substance to said suspension to make pH at least 8, thereby stabilizing the silicic acid as a colloidal solution, (vi) separating a calcium fluoride solid and the colloidal solution of silicic acid from said suspension, and (vii) recycling the separated calcium fluoride as a starting calcium fluoride.

Abstract: A process, and the product produced thereby, for the preparation of a waste solidification material from hardened fluorogypsum as a by-product of the manufacture of hydrofluoric acid by reacting fluorospar with sulfuric acid, removing hydrogen fluoride from the reaction product, slurrying the by-product with water, placing the slurried by-product fluorogypsum in settlement ponds until the fluorogypsum hardens, the hardened fluorogypsum having a pH of greater than about 5 to about 13, including heating the hardened fluorogypsum to evaporate substantially all water physically mixed with the fluorogypsum and further heating the fluorogypsum to reduce the water chemically bound to calcium sulfate in the fluorogypsum to form about 0.5% to about 9% by weight.

Abstract: A process, and the product produced thereby, for the preparation of a waste solidification material from hardened fluorogypsum as a by-product of the manufacture of hydrofluoric acid by reacting fluorospar with sulfuric acid, removing hydrogen fluoride from the reaction product, slurrying the by-product with water, placing the slurried by-product fluorogypsum in settlement ponds until the fluorogypsum hardens, the hardened fluorogypsum having a pH of about 3 to about 5, including heating the hardened fluorogypsum to evaporate substantially all water physically mixed with the fluorogypsum and further heating the fluorogypsum to reduce the water chemically bound to calcium sulfate in the fluorogypsum to from about 0.5% to about 9% by weight.

Abstract: Hydrogen fluoride is produced by the electrodialysis of an alkali metal fluoride salt solution or an ammonium fluoride solution in an electrodialysis cell having an anode compartment and a cathode compartment spaced from one another by an inner electrodialysis compartment bounded by spaced cation exchange membranes.

Abstract: A process for producing hydrogen fluoride with use of fluorite as starting material and by conducting reactions in a first reactor and a second reactor wherein a reaction of fluorite with sulfuric acid, sulfuric anhydride and steam in the first reactor is conducted at a conversion of from 35 to 90% while maintaining the reaction temperature within a range of from 140.degree. to 240.degree. C. by controlling the respective amounts of the sulfuric anhydride, steam and sulfuric acid.

Abstract: A novel method is provided for the production of anhydrous hydrofluoric acid from low-grade metallic fluorides using an intermediate aluminum fluoride compound. The method involves the reaction of low-grade metallic fluorides such as fluorspar with sulfuric acid to produce weak hydrofluoric acid. The weak acid is then reacted with a metallic salt (such as aluminum chloride) to form precipitated aluminum fluoride (AlF.sub.3.3H.sub.2 O). After dewatering, the aluminum fluoride is reacted with strong sulfuric acid to form aluminum sulfate and strong hydrofluoric acid.

Abstract: In the process for the production of synthetic anhydrite and pure hydrofluoric acid, a reaction is initiated using fluorspar with a mixture containing sulphuric acid, oleum and the reflux of the acidic scrubbing. The aim is to produce synthetic anhydrite which contains only the desired small proportion of CaF.sub.2, while the free H.sub.2 SO.sub.4 is completely neutralized, but other desirable accelerators are still retained. The reaction is so arranged that fluorosulphonic acid does not enter the reactor at all or only in minute quantity and the new formation of fluorosulphonic acid is effectively repressed. For this end, the components of CaF.sub.2 and acid mixture are fed into the reactor at an elevated temperature and the reactor intake is so heated, whereby the reaction is initiated at 100.degree. C. and thus new formation of fluorosulphonic acid is arrested. The exhaust gases from the reactor are hot-dried in a first stage and the dust is expelled, before the material is cooled in the subsequent stages.

Abstract: A method for recovery of fluoride values from spent potlining and fluoride containing insulating materials associated with the potlining is disclosed. Spent potlining and the insulating materials are reduced to a fine particle size and incinerated. The ash residue is leached with a dilute caustic and the leachate is treated with a calcium compound to precipitate calcium fluoride. The calcium fluoride is dried to a moisture content of less than 0.1 percent and is treated with about 93 to 99 percent concentration of sulfuric acid to produce hydrogen fluoride gas and a metal sulfate. The hydrogen fluoride gas is fed into an alumina dry scrubber to produce alumina with absorbed fluorides to be used as feed material to reduction cells used in the manufacture of aluminum by electrolytic reduction. The metal sulfate residue is treated with lime and constitutes an environmentally safe product which can be disposed of as landfill material.

Abstract: In the generation of hydrogen fluoride gas for the production of AlF.sub.3 by the reaction of fluorspar with concentrated sulphuric acid a small amount of aluminium sulphate is introduced into the reactive mix to assist in the retention of phosphorous compounds in the solid residues of the reaction and thus reduce the phosphorous content of the gaseous HF. Aluminium sulphate may be added as alum or may be generated in situ in the sulphuric acid by addition of an alumina hydrate, preferably before the acid is brought into contact with fluorspar. The addition of a small amount of calcium carbonate to the fluorspar also improves retention of phosphorous compounds in the solid residues in some instances.

Abstract: A method of recovering fluorine, e.g. as hydrogen fluoride, from wastes of aluminum electrolysis furnaces, chemisorbents, adsorbents or absorbents, etc. in which the fluorine-containing material is subjected to pyrohydrolysis in an expanded fluid bed and the HF-containing gas is subjected to condensation or scrubbing for the removal of the HF therefrom. According to the invention, the exhaust gases from the fluidized bed are cooled by direct contact with solids which can be circulated in a separate cycle and are themselves cooled in a cooler, e.g. by contact with gas which is to be fed to the expanded fluidized bed. The circulated solids thus allow recovery of the sensible heat of the gas without diluting it.

Abstract: An improved method for producing hydrogen fluoride from fluoride bearing ores, such as fluorospar and fluorapatite, by reaction of the ore as a slurry in fluorosulfonic acid. The slurry is heated by the exothermic heat of the reaction to vaporize volatile phosphorous compounds and substantial quantities of hydrogen fluoride. The calcium fluoride is substantially reacted to form hydrogen fluoride. High silica fluorospar ores can be used since silicon tetrafluoride is not formed with fluorosulfonic acid. Another feature provides for addition of calcium fluoride to the slurry to react with the by-product sulfuric acid in the residual solids to eliminate the sulfuric acid recovery step in the process. Hydrogen fluoride produced is recovered, together with the hydrogen fluoride produced from the hydrolysis or pyrolysis of the intermediate fluorophosphorous compounds. Additionally, at least a portion of the hydrogen fluoride can be reacted with sulfur trioxide to form fluorosulfonic acid for makeup in the process.

Abstract: A process for the production of highly pure concentrated hydrofluoric acid by purifying crude HF gas containing H.sub.2 O, SO.sub.2, SiF.sub.4, S,CaF.sub.2, H.sub.2 SO.sub.4 and CaSO.sub.4 and obtained in the reaction of fluorite and sulphuric acid, whereby the resultant HF has an H.sub.2 SO.sub.4 content of the order of a few ppm, there are substantially no deposits of CaSO.sub.4 in the first H.sub.2 SO.sub.4 washing circuit and the service life of the system is considerably lengthened.

Abstract: Anhydrous hydrogen fluoride is manufactured by dropping small particles of a metal fluoride, e.g., calcium fluoride, through a reaction zone countercurrent to a gas stream containing sulfur trioxide, sulfuric acid and water vapor.

Abstract: In the reaction of phosphate-containing fluorspar with sulphuric acid to produce gaseous hydrofluoric acid, withdrawing the hydrofluoric acid and condensing it, the improvement which comprises adding to the fluorspar a reactive iron compound in an amount approximately equivalent to the phosphate content whereby the phosphate content of the condensed hydrofluoric acid is markedly diminished. The reactive iron compound can be contained in another fluorspar which is blended in the first fluorspar in the requisite amount and/or it can be an iron oxide, fluoride or sulphate, or a hydrated or hydratable iron compound added to the phosphate-containing fluorspar in about 0.2 to 5% by weight calculated as Fe.sub.2 O.sub.3 content and based on the fluorspar.

Abstract: There is disclosed an improvement in the process of manufacturing HF wherein sulfur accumulates in HF process equipment. The improvement comprises adding to the process equipment sufficient SO.sub.3 to remove the sulfur and emptying the equipment.

Abstract: In the production of hydrofluoric acid and calcium sulfate by subjecting sulfuric acid and fluorspar to a partial preliminary reaction in a preliminary reaction zone and the reaction is completed in an after-reaction zone at a temperature from about 100.degree. to 500.degree. C, the improvement which comprises effecting the preliminary reaction by circulating preliminary reaction product through said preliminary reaction zone, adding to the circulating preliminary reaction product at spaced locations in the preliminary reaction zone sulfuric acid preheated to a temperature of about 80.degree. to 200.degree. C and fluorspar preheated to a temperature of about 400.degree. to 800.degree. C, removing from said preliminary reaction zone gaseous hydrofluoric acid and a substantially dry mixture of calcium sulfate, unreacted sulfuric acid and fluorspar, and passing said dry mixture of calcium sulfate, unreacted sulfuric acid and fluorspar to said after-reaction zone.

Abstract: A method of disposing of silica dust recovered from the smoke of metallurgical furnaces by producing aluminum fluoride therefrom for use in electrolytic melting furnaces is disclosed. Fluorspar and the precipitated amorphous silicon dioxide are treated with steam at elevated temperatures whereby hydrogen fluoride-containing gases are produced and then these gases are passed through a layer of aluminum oxide. Part of the gaseous hydrogen fluoride will then react with the alumina to form aluminum fluoride and part of it will be adsorbed in the alumina whereby an intimate mixture of alumina and fluorine is obtained which is useful in electrolytic furnaces.