Abstract: A process is provided for producing potassium sulfate from potassium chloride and sulfuric acid. The process entails mixing potassium chloride with the water to form a potassium chloride slurry which is mixed with recycled sulfuric acid to form a K+, Ct?, SO42? acid mixture. This mixture is subjected to a crystallization process that produces potassium sulfate crystals and a hydrochloric acid-water vapor. The hydrochloric acid is separated from the hydrochloric acid-water vapor to form a hydrochloric acid solution.

Abstract: Provided is a method for producing a hydrogen chloride that is capable of efficiently producing a hydrogen chloride with a simple facility. The hydrogen chloride is produced by a method including causing an inert gas to be in gas-liquid contact with a hydrochloric acid in which a concentration is 20 mass % to 50 mass %, distilling the hydrochloric acid with which the inert gas is in gas-liquid contact in the gas-liquid contact and separating a hydrogen chloride from the hydrochloric acid to obtain a crude hydrogen chloride, dehydrating the crude hydrogen chloride obtained in the separating, and compressing and liquefying the dehydrated crude hydrogen chloride obtained in the dehydrating, and purifying the liquid crude hydrogen chloride by distillation.

Abstract: A process for the preparation of HF and anhydrite from reaction of calcium fluoride in the form of fines and sulfuric acid. The content of sulfuric acid is kept in a range where no agglomeration occurs. In such process, dust originating from natural fluorspar can be reacted, as well as synthetic calcium fluoride, e.g., from calcium fluoride and optionally calcium carbonate containing solids from treating a waste gas or waste water with basic calcium compounds to remove contained HF.

Abstract: A method is disclosed for production of a sulfate-containing chlorine free salt and anhydrous gaseous HCl from a metal chloride (MClx), oleum and water. MClx and oleum are mixed together with a water-containing liquid, forming gaseous HCl and a solution of a sulfate-containing salt. The salt is precipitated from the solution, and in a preferred embodiment, the supernatant liquid from the precipitation is recycled to the reaction mixture as the water-containing liquid in subsequent reaction cycles. The exothermicity of the reaction between the water-containing liquid and the oleum is sufficient to remove chlorine in the form of substantially pure useful HCl and enables the process to proceed without additional heating of the reaction mixture. When the metal is potassium, this method produces high-purity novel sulfate salts with high potassium content K3(NH4)(SO4)2, 3K2SO4.MgSO4 and 3K2SO4.CanMg1-nSO4.

Abstract: A method is disclosed for production of a sulfate-containing salt and anhydrous gaseous HCl from a metal chloride (MClx) and oleum. MClx and oleum are mixed together with a water-containing liquid, forming gaseous HCl and a solution of a sulfate-containing salt or double salt. The salt is precipitated from the solution, and in a preferred embodiment, the supernatant liquid from the precipitation is recycled to the reaction mixture as the water-containing liquid in subsequent reaction cycles. In a preferred embodiment, HCl discharged from the reaction mixture is scrubbed to remove dust, water vapor and traces of H2SO4, yielding anhydrous HCl of >90% purity. The exothermicity of the reaction between the water-containing liquid and the oleum is sufficient that, unlike methods known in the prior art, the process proceeds quickly and efficiently without any necessity for additional heating of the reaction mixture.

Abstract: The invention concerns a method for processing heavy metal-laden spent sulfuric acid. For this, iron-laden spent sulfuric acid or iron-laden sulfuric materials obtained therefrom are reacted with a material that contains iron chloride and optionally other metal chlorides, producing iron (II) sulfate. The spent sulfuric acid preferably derives from titanium dioxide production.

Abstract: Spent, acidic solutions comprising cupric chloride and hyrdrochloric acid from the copper etching process are regenerated by a process in which the acid is subjected to distillation with sulfuric acid. In one embodiment, the process comprises (a) providing a spent etchant comprising at least about 10% by weight chloride and at least about 5% dissolved copper; (b) adding at least about 2 moles of sulfuric acid per mole of dissolved copper to the spent etching solution, thereby converting copper chloride into hydrochloric acid and precipitated copper sulfate; (c) distilling the mixture from step (b) to vaporize at least a portion of the hydrochloric acid; (d) condensing at least a portion of the vaporized hydrochloric acid; (e) separating at least a portion of the precipitated copper sulfate from the residual liquid, wherein said residual liquid comprises sulfuric acid; and (f) reusing at least a portion of the residual liquid as a sulfuric acid source in step (b).

Abstract: A batch process for co-producing anhydrous hydrogen bromide and a purified bisulfate salt comprising: (a) charging a batch reactor with a bromide salt slurry, wherein the slurry is more than 50% by weight bromide salt; (b) reacting the slurry with sulfuric acid in a batch reaction wherein bromide salt is consumed to produce crude aqueous hydrogen bromide and crude bisulfate salt, the crude bisulfate salt containing bromine; (c) prior to or concurrently with step (b) adding hydrogen bromide to the reactor; (d) purifying the crude hydrogen bromide to produce anhydrous hydrogen bromide; and (e) removing bromine from the crude bisulfate salt to form a purified bisulfate salt.

Abstract: A process for co-producing anhydrous hydrogen bromide and a purified bisulfate salt by (a) reacting a bromide salt with sulfuric acid to produce crude hydrogen bromide and crude bisulfate salt; (b) purifying the crude hydrogen bromide to produce anhydrous hydrogen bromide; and (c) removing bromide from the crude bisulfate salt to form a purified bisulfate salt. There are also provided improvements in the bisulfate purification and bromine removal, whereby bromine is removed from the system by a distillation process and the bromide is removed from the crude bisulfate via a spray drying process.

Abstract: Process for the conversion of sodium bromide to anhydrous hydrobromic acid and sodium bisulfate, said process with the following sequential steps: reaction of sodium bromide and sulfuric acid in a solution of water to produce hydrobromic acid and sodium bisulfate wherein the conversion of sodium bromide is greater than about 99%; adsorption of iron bromide onto a solid adsorbent; separation of hydrobromic acid and water from the sodium bisulfate; separation and drying of hydrobromic acid; and solidification of the sodium bisulfate into a flaked or granular form.

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: Process for the conversion of sodium bromide to anhydrous hydrobromic acid and sodium bisulfate, said process with the following sequential steps: reaction of sodium bromide and sulfuric acid in a solution of water to produce hydrobromic acid and sodium bisulfate wherein the conversion rate is greater than about 95%; separation of hydrobromic acid and water from the sodium bisulfate; separation of hydrobromic acid from water; and drying of hydrobromic acid.

Abstract: The specification discloses a continuous process for producing hydrogen chloride whereby sulfuric acid and an alkali metal chloride are fed to a direct fired reaction chamber in a molar ratio of approximately one to one, products comprising hydrogen chloride and the corresponding alkali metal sulfate are withdrawn, and the hydrogen chloride is separated from combustion gases. The reaction chamber provides for the counter flow of gaseous and solid streams within the reaction chamber, such that a chloride-free sulfate is obtained.

Abstract: Process for the conversion of sodium bromide to anhydrous hydrobromic acid and sodium bisulfate, said process with the following sequential steps: reaction of sodium bromide and sulfuric acid in a solution of water to produce hydrobromic acid and sodium bisulfate wherein the conversion rate is greater than about 95%; separation of hydrobromic acid and water from the sodium bisulfate; separation of hydrobromic acid from water; and drying of hydrobromic acid.

Abstract: Process for the conversion of sodium bromide to anhydrous hydrobromic acid and sodium bisulfate, said process with the following sequential steps: reaction of sodium bromide and sulfuric acid in a solution of water to produce hydrobromic acid and sodium bisulfate wherein the conversion of sodium bromide is greater than about 99%; adsorption of iron bromide onto a solid adsorbent; separation of hydrobromic acid and water from the sodium bisulfate; separation and drying of hydrobromic acid; and solidification of the sodium bisulfate into a flaked or granular form.

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: A process for the production of hydrochloric acid and neutralized sulfates comprising: reacting sulfuric acid with an alkaline metal chloride in order to obtain a liquor containing hydrochloric acid, an acid alkaline metal sulfate and an excess of sulfuric acid; separating the hydrochloric acid from the liquor containing the hydrochloric acid, the acid alkaline metal sulfate and the excess of sulfuric acid; neutralizing the acid alkaline metal sulfate and the excess sulfuric acid by adding to the remaining liquor after the separation of the hydrochloric acid a neutralizing agent to obtain a neutralized mass; cooling the neutralized mass to crystallize the neutralized alkaline metal sulfate and obtain neutralized alkaline metal sulfate crystals; and separating the neutralized alkaline metal sulfate crystals from the liquor.

Abstract: The invention relates to a process for utilizing waste salt mixtures from HALEX reactions, comprising at least one alkali metal chloride and at least one alkali metal fluoride or bifluoride, and optionally one or more organic compounds, which are depleted by extraction, by contacting the resulting waste salt mixture with concentrated sulfuric acid, removing the resulting hydrogen chloride for the most part by flushing with an inert gas, and reacting the salt-containing sulfuric acid with calcium fluoride to give hydrogen fluoride and alkali metal sulfate-containing calcium sulfate, which can be processed to give a building material binder.

Abstract: A process for the production of hydrochloric acid and neutralized sulfates comprising: reacting sulfuric acid with an alkaline metal chloride in order to obtain a liquor containing hydrochloric acid, an acid alkaline metal sulfate and an excess of sulfuric acid; separating the hydrochloric acid from the liquor containing the hydrochloric acid, the acid alkaline metal sulfate and the excess of sulfuric acid; neutralizing the acid alkaline metal sulfate and the excess sulfuric acid by adding to the remaining liquor after the separation of the hydrochloric acid a neutralizing agent to obtain a neutralized mass; cooling the neutralized mass to crystallize the neutralized alkaline metal sulfate and obtain neutralized alkaline metal sulfate crystals; and separating the neutralized alkaline metal sulfate crystals from the liquor.

Abstract: The specification discloses a continuous process for producing hydrogen chloride whereby sulfuric acid and an alkali metal chloride are fed to a direct fired reaction chamber in a molar ratio of approximately one to one, products comprising hydrogen chloride and the corresponding alkali metal sulfate are withdrawn, and the hydrogen chloride is separated from combustion gases. The reaction chamber provides for the counter flow of gaseous and solid streams within the reaction chamber, such that a chloride-free sulfate is obtained.

Abstract: In minimizing effluents from a cellulose pulp mill, liquid effluents from a bleach plant are concentrated, and then incinerated to produce a residue including sodium, sulfate, and sodium chloride. This residue is distilled with sulfuric acid to produce gaseous hydrogen chloride and remaining residue, the HCl being used in chloride dioxide production for the bleach plant, while the remaining residue is passed to the recovery loop (e.g. recovery boiler). Sulfur containing gases from the non-condensible gas system may be combusted to produce gaseous sulfur dioxide, which is then converted to sulfuric acid, to distill the residue. Where a non-chlorine bleach plant is provided, the liquid effluents may be concentrated in evaporators and then passed directly to the recovery boiler. The liquid streams in the mill are managed by a cascade principle to reserve the cleanest water for only those processes where it is needed while minimizing its use where it is not necessary.

Abstract: The purpose of the method is to remove chlorides and fluorides from a valuable metal raw material by leaching the raw material into sulphuric acid solution and by crystallizing the valuable metal sulphate selectively out of the solution. The valuable metal sulphate crystals are washed in sulphuric acid solution, and the recovered dechlorinated and defluorinated crystals are leached into water and conducted into electrolysis. The sulphuric acid solution employed in the raw material leaching and in the crystal washing is preferably the same as the return acid of the electrolysis. Chlorides and fluorides are removed from the mother liquor of crystallization in the bleed.

Abstract: Potassium chloride and sulfuric acid are reacted in a recycled aqueous solution in the stoichiometric ratio required for potassium sulfate production. Hydrogen chloride produced by the reaction of the potassium chloride and sulfuric acid is evaporated in admixture with water or in anhdrous form. The resulting solution is cooled to crystallize a potassium sulfate salt, preferably potassium bisulfate. The potassium sulfate salt is separated from the mother liquor and the mother liquor is recycled to the reaction step. The potassium sulfate salt is dissolved in an aqueous solution and sequentially decomposed to produce potassium sulfate and a mother liquor rich in sulfuric acid. The mother liquor rich in sulfuric acid is concentrated and recycled to the reaction step.

Abstract: Treatment of waste water containing chlorides comprising treatment with Ca (OH).sub.2 or CaCO.sub.3 to convert the chlorides to CaCl.sub.2, adding sulfuric acid to said water in a reaction vessel to produce hydrochloric acid and gypsum, circulating the mixture in a closed cycle between the reaction vessel and a distillation column for the extractive distillation of the resulting hydrochloric acid, and filtering out the accumulating gypsum sludge from the treated waste water, wherein the added amount of waste water amount of hydrochloric acid correspond to the amount of sludge exiting the reaction vessel or the amount of distillate removed from the distilling column and the amount of gypsum separated, and the hydrochloric acid concentration in the liquid is less than the maximum azeotropic concentration for a mixture of H.sub.2 O and HCl.

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: This improved method comprises a first dry step of reacting concentrated sulfuric acid and potassium sulfate with potassium chloride at about 300.degree. C. in a slurried state to obtain a mixed slurried salts of K.sub.n H.sub.2-n SO.sub.4 (n being 1.3 to 1.4); a second wet step of dissolving said mixed salts and additional raw potassium chloride in water, the amount of water being limited to some extent, heating the solution to 60.degree. to 90.degree. C. in order to take place a wet reaction, and cooling the solution to 50.degree. to 20.degree. C. to deposit potassium sulfate crystals from the solution in order to obtain the final product and filtrate; and a third circulating step of evaporating the filtrate to obtain a cake of mixed salts of acid potassium sulfate and potassium chloride, and returning circulatingly the cake to the first stage as part of raw materials.

Abstract: Alkali and alkaline earth metal chlorides contained in a residue of a chlorination process of a feed material of bauxite or clay associated with coal are removed by the addition of sulfuric acid which causes their conversion to their sulfate form, and the simultaneous production of hydrochloric acid. The residue, which has been rendered environmentally acceptable, can be disposed of readily, for example, to an ash pond or disposal area for flue gas desulfurization sludges. The hydrochloric acid is then recycled to the chlorination process. The hydrochloric acid may be utilized, for example, as a binder of the feed material, to prechloridize the feed material or as a portion of the leach solution when the chlorination process is a hydrochloric acid leach.

Abstract: An apparatus is disclosed for producing an alkali metal salt of a mineral acid, characterized by the provision of a specific agitating means, said agitating means having a pair of shafts adapted to contra-rotate and a plurality of columnar agitating elements securely attached to each of said pair of shafts and being so constructed that it forcibly causes the migration of the reaction mixture at least in the region where the liquid phase of the reaction mixture is substantially continuous and forcibly causes the kneading of the reaction mixture at least in the region where the solid phase of the reaction mixture is substantially continuous.

Abstract: A small amount of chlorine contained in the converted potassium sulfate obtained by dry-mixing and heating potassium chloride with sulfuric acid or potassium hydrogensulfate can greatly be reduced by totally pulverizing the potassium sulfate to 60 mesh pass, and then calcining at 300.degree. to 500.degree. C. for 5 minutes to one hour. The chlorine content is further reduced by adding a small amount of water or dilute sulfuric acid prior to calcination.

Abstract: A process for producing a purified hydrochloric acid from hydrogen chloride gas generated by reacting an alkali chloride with sulfuric acid is provided, which process comprises washing the hydrogen chloride gas with a hydrochloric acid having a saturation concentration and having the resulting gas absorbed in water.This process does not require such a particular purification step as redistillation or reabsorption.

Abstract: Hydrochloric acid produced by reacting an alkali chloride with sulfuric acid to prepare hydrogen chloride gas, followed by having the gas absorbed in water, contains a slightest amount of Br.sub.2 and other coloring materials as volatile impurities, but such amounts of impurities can be removed according to a purifying process in which the resulting hydrochloric acid is treated with an inert gas or a mixture of an inert gas with oxygen.

Abstract: A process of producing a potassium sulfate salt comprising reacting sulfuric acid with potassium chloride at an equivalent ratio of sulfuric acid to potassium chloride of 1.07 to 1.40 at a temperature of from the melting point of potassium bisulfate to about 500.degree. C. while allowing the resulting solid-liquid mixture at the final reaction stage to be substantially in a state of wet cake, said potassium bisulfate being present in the reaction system until the termination of the reaction because of the excess sulfuric acid. In such a process, the reaction proceeds smoothly at a relatively low temperature and is completed in an extremely shortened period of time to produce a potassium sulfate salt with an extremely low chlorine content which is useful as a raw material for the production of potassium-containing chemical manures to be suitably applied onto the farmland of tobacco etc. which are apt to have their growth hampered by chlorine values.

Abstract: A process for converting chloride salts and sulfuric acid to sulfate salts and elemental chlorine is disclosed. A chloride salt and sulfuric acid are combined in a furnace where they react to produce a sulfate salt and hydrogen chloride. Hydrogen chloride from the furnace contacts a molten salt mixture containing an oxygen compound of vanadium, an alkali metal sulfate and an alkali metal pyrosulfate to recover elemental chlorine. In the absence of an oxygen-bearing gas during the contacting, the vanadium is reduced, but is regenerated to its active higher valence state by separately contacting the molten salt mixture with an oxygen-bearing gas.

Abstract: Alkali metal fluosilicate is used as an intermediate reactant in a process for the production of hydrochloric acid and an alkali metal sulfate from sulfuric acid and an alkali metal chloride. The process includes the reaction of alkali metal fluosilicate with sulfuric acid to produce alkali metal sulfate and H.sub.2 SiF.sub.6, the latter being reacted with alkali metal chloride to produce HCl and alkali metal fluosilicate. The resulting hydrochloric acid may be converted to anhydrous hydrogen chloride. A continuous process for the production of hydrochloric acid and of alkali metal sulfate such as potassium sulfate from an alkali metal fluosilicate material is also disclosed.

Abstract: The foaming tendencies of continuous liquid-solid reactions which evolve gas are reduced by subjecting the reactant stream simultaneously to non-turbulent flow through an enclosed conduit having a vapor space above the flowing stream and to mild agitation to increase the liquid-solid and gas-liquid interface areas.

Abstract: Potassium sulfate (K.sub.2 SO.sub.4) is prepared by reaction of potassium chloride and sulfuric acid in an aqueous medium by initially removing evolved HCl in the gaseous form at temperatures of about 65.degree.-120.degree. C., then removing the remaining HCl as an HCl/water azeotrope at temperatures of about 90.degree. to 110.degree. C., restoring to the reaction mixture the amount of water removed with the azeotrope, and permitting the potassium sulfate to crystallize from the solution.

Abstract: Potassium sulfate (K.sub.2 SO.sub.4) is prepared by contacting potassium chloride with an aqueous solution containing potassium bisulfate at a temperature of about 65.degree.-110.degree. C., cooling the solution and permitting the potassium sulfate to crystallize from solution.

Abstract: A process for efficiently removing nitrogen oxides with a very high rate from waste gas is provided wherein nitrogen monoxide contained in the gas is oxidized by chlorine dioxide or ozone, and then the oxidized gas is brought into contact with sodium chlorite in water solution in an absorption column.