Abstract: Process for extraction or recovery of acids, in particular hydrofluoric acid, hydrochloric acid and nitric acid, from solutions of these acids containing metal, by pyrohydrolytic treatment and subsequent absorption and/or condensation of the acid gases thus formed in an aqueous absorption solution, in which process the solids produced are removed. In order to guarantee economical acid recovery in existing plants without requiring large-scale adaptation, the waste pickling liquor is subjected to pre-concentration first of all before pyrohydrolysis, using the heat contained in the exhaust gas from the pyrohydrolysis.

Abstract: A process is disclosed for removing the very fine oxide particles produced during regeneration of used pickling acids by pyrolysis. The process includes the step of spraying water into the gaseous stream to produce a mist of fine droplets and thereafter passing the gaseous stream through a liquid separator. The invention is also directed to a plant for carrying out the process where the plant includes a nozzle to spray water droplets into the gaseous stream before the drop separator.

Abstract: A process for forming an aqueous chloride leachant from a spent aqueous chloride leach liquor which process comprises passing a spent aqueous chloride leach liquor and gases containing hydrogen chloride through a preconcentrator to form a concentrated aqueous chloride leach liquor by partial evaporation of water therefrom and absorption of hydrogen chloride; withdrawing a portion of the concentrated aqueous chloride leach liquor; roasting the remainder of the concentrated aqueous chloride leach liquor to generate a metal oxide, and gases containing hydrogen chloride; and passing the gases containing hydrogen chloride to the preconcentrator.

Abstract: A substantial part of the water contained in the spent solution is evaporated under vacuum in an evaporator (7) and is then condensed, so as to obtain slightly acidic water and a concentrated acidic solution polluted by zirconium fluoride ZrF.sub.4. The polluted concentrated acidic solution is treated by evaporation under vacuum in a crystallizer (8), so as to obtain zirconium fluoride ZrF.sub.4 crystals and a purified concentrated acidic solution. The slightly acidic water and the purified concentrated acidic solution are mixed in desired proportions in order to obtain a regenerated pickling solution.

Abstract: In a pickling process for stainless steels or similar ferrous alloys, continuous reoxidation of Fe.sup.2+ to Fe.sup.3+ and/or NOx to nitric acid in the pickling liquor is economically performed by continuously treating a portion of the pickling liquor into a separate reactor where it is contacted with oxygen onto a catalytic bed and recycling the solution so reoxidized into the pickling bath. The need of continuously adding an oxidant in the form of hydrogen peroxide and of stabilizing compounds into the pickling bath is eliminated altogether thus achieving a dramatic reduction of the processing costs.

Abstract: Reagent grade hydrochloric acid having an iron content of less than 200 p.p.b. is made from an industrial organic isocyanate manufacturing process by removing hydrogen chloride from organic isocyanates produced in the reaction between phosgene and an organic amine, converting the hydrogen chloride to concentrated aqueous hydrochloric acid, and contacting the acid with a strongly basic anion exchange resin.

Abstract: Regeneration of hydrochloric acid by hydrolysis of iron chloride in aqueous solution employs a Pelletiser (5) after preconcentration of acid solution in a "Pre-Evaporator" (1). Pelletiser (5) controls pellet mixture to between 12% and 14% free water by recycling dried solids from Roaster (3), from Screen (7), or from dust removal Cyclone (9), and waste liquid from Preconcentrator (1). Preconcentrator (1) is contacted with superheated gas from Fluid Bed Roaster (3). Rotary Drier (6) dries pellets with a concurrent hot gas stream and the pellets are screened at (7) with oversize being sent to a Mill (8), undersize recycled to Pelletiser (5), and sized feed delivered to Roaster (3). HCl is produced as gas offtake from Preconcentrator (1) and passes via a demisting Cyclone into adiabatic Absorption Process section (11), where weak acid liquor and water (10) are added as required.

Abstract: A process for reducing the residual chloride present in iron oxides, particularly in regenerated iron oxides produced from hydrochloric acid waste liquid generated from steel pickling, by post-synthesis treatment of the iron oxides with yellow iron oxide, and subsequently heating the mixture at a temperature sufficient to release at least a part of the crystalline water contained in the yellow iron oxide to facilitate the removal of residual chloride present in iron oxides. The purified regenerated iron oxides are particular suitable for making high-grade ferrites.

Abstract: The present invention is a composition, a synthesis of the composition and a method of using the composition for selectively adsorptively separating nitrogen from oxygen wherein the composition is a crystalline EMT with a Si/Al ratio less than 2.0 and a micropore volume determined in the sodium and/or potassium form of at least 0.20 cm.sup.3 /g and a lithium cation exchange of at least 80%, preferably including an intergrowth with a crystalline FAU structure, wherein the pure or intergrowth compositions have the chemical formula:M.sub.2/n O:X.sub.2 O.sub.3 :(2.0 to <4.0)SiO.sub.2wherein M=one or more metal cations having a valence of n, and X is selected from the group consisting of aluminum, gallium and boron, preferably aluminum.

Abstract: A method and apparatus for forming a slurry of metal oxide in a mineral or the like (e.g. of magnesium or calcium oxide) and introducing the slurry to an acid neutralization process in a time period before substantial hydration of the oxide has occurred.

Abstract: Process for treating aqueous media containing metal ions having valences of +2 and higher and optionally acid comprising:(a) contacting the aqueous media, at a pH of about 1-5, with an effective amount of product recycled from step (b) to dissolve at least some metal carbonates, produce at least some CO.sub.2, convert at least some metal ions having a valence of at least +3 to metal hydroxide precipitates, and neutralize some acid, if present;(b) contacting the product of step (a), at a pH of about 4-8.5, with an effective amount of Na.sub.2 CO.sub.3 to convert at least some metal ions of +2 valence to metal carbonate precipitates and form at least some dissolved sodium salts;(c) recovering, from a portion of the product from step (b) that is not recycled, metal carbonates, metal hydroxides, and sodium salts.

Abstract: Volatile acids containing metal salt impurities, such as metal pickling solutions-are regenerated by a process in which the acid is subjected to sulfuric acid distillation. Resulting volatile acid vapor is condensed and recycled to the pickle tank, while the residual acid mixture is treated in an acid sorption unit, preferably of the acid retardation type. Acid sorbed in the acid sorption unit is periodically eluted with water and recycled, while metal impurities are rejected in a deacidified by-product solution.

Abstract: A two step method of converting ferrous chloride from a pickling liquor to produce hydrochloric acid and ferric sulfate is disclosed. The ferrous chloride is first mixed with sulfuric acid to produce ferrous sulfate and HCl. The HCl is carried to an absorbtion tower where most of the HCl is collected and the remainder is returned to the reactor. The ferrous sulfate is separated from the sulfuric acid. The unreacted sulfuric acid is returned to the reactor and the ferrous sulfate is transported to a second reactor where it is reacted with sulfuric acid and air (O.sub.2) to produce ferric sulfate. The ferric sulfate is removed from the second reactor. Both reactions are carried out at relatively low temperatures under atmospheric pressures.

Abstract: A process for reducing the residual chloride present in iron oxides, particularly in regenerated iron oxides produced from hydrochloric acid waste liquid generated from steel pickling, by post-synthesis treatment of the iron oxides with sulfuric acid optionally followed by drying and calcining. The purified regenerated iron oxides are particular suitable for making iron oxide based catalysts such as ethylbenzene dehydrogenation catalysts and high-grade ferrites.

Abstract: A method for treating waste pickle liquor solution comprising the steps of (a) adding a flocculating agent to the pickle liquor solution; (b) allowing at least some of the silica in the pickle liquor to begin to flocculate; (c) again adding a flocculating agent to the pickle liquor solution; (d) allowing the floccules containing silica formed in step (b) to increase in size; and (e) physically separating floccules formed in step (d) from the pickle liquor solution.

Abstract: A method of regenerating an etching waste fluid, includes the steps of dissolving HCl gas in an etching waste fluid at a temperature falling within a range of 20.degree. C. to 50.degree. C. and crystallizing NiCl.sub.2 and FeCl.sub.2 crystals, the etching waste fluid containing NiCl.sub.2, FeCl.sub.3, and FeCl.sub.2 and being obtained by etching Ni or an Ni alloy with an etching solution consisting of an aqueous solution containing FeCl.sub.3, distilling a mother liquor at the atmospheric pressure after crystallization and separation thereof to reduce the HCl concentration in the mother liquor, and distilling, at a reduced pressure, a concentrate obtained upon distillation at the atmospheric pressure to further reduce the HCl concentration, thereby obtaining an aqueous solution containing FeCl.sub.

Abstract: The subject of the invention is a process for separating silicic compounds from baths for cleaning steel substrates containing iron ions and silicic compounds, consisting of the following stages:a) a concentrated spent cleaning bath is cooled in a controlled manner to a temperature below 60.degree. C. so as to precipitate the silicic compounds,b) the cleaning bath is allowed to cool for at least 2 hours,c) the cleaning bath is reheated,d) the silicic compounds precipitated from the cleaning bath are separated off.

Abstract: A liquid oxidizing system has a closed circuit in which a liquid containing matter to be oxidized is circulated. The circuit is provided with an ejector for forming a jet stream of the liquid into which oxygen, or both oxygen and an oxidizing catalyst are supplied. The oxygen (and the catalyst) rapidly contacts the matter to be oxidized in the jet stream and oxidizes it. The system is not only applicable to the treatment of waste water, such as from factories, but also useful for making a product by oxidizing a liquid, e.g. iron polysulfate which is a good coagulant.

Abstract: This process in which the used bath is recycled after concentration at (1) by elimination of water at (2), followed by a treatment for recovering iron oxides at (10), is characterized in that it comprises carrying out a tangential microfiltration at (5) of the concentrated bath so as to separate therefrom the silicon compounds in the non-ionic form and thereby concentrate them, and recirculating the major part of the fraction of this bath (11-17) containing these concentrated silicon compounds so as to promote the precipitation of the non-ionic compounds of the silicon.

Abstract: During the pickling, etching, chemical shaping etc. of steels, stainless steels, special alloys and special metals and the dissolution of those metals, metalliferous solutions of the acids employed arise in the course of such processes which must either be disposed of by neutralization or be used for the recovery of the acids and metals by expensive processes. According to the invention the production or recovery of nitric acid or a mixture of nitric acid and hydrofluoric acid takes place by spray-roasting the solutions at temperatures of 200.degree. to 500.degree. in a reactor (1) and subsequent absorptions or condensation of the gases generated in column means (7, 8) at temperatures of 0.degree. to 70.degree. C.

Abstract: Concentrated aqueous solutions of ferric chloride, directly useful as flocculating agents in a variety of water treatments, are prepared by (a) reacting chlorine, advantangeously a stoichiometric amount of chlorine, with an aqueous solution of ferrous chloride in the presence of an aqueous solution of ferric chloride, in an essentially vertical reaction zone, with at least a major amount of the ferrous chloride solution being introduced to the upper section of such reaction zone, at least a major amount of the chlorine being introduced countercurrently to the base of such reaction zone, and the ferric chloride solution being introduced at at least one point intermediate such ferrous chloride solution/chlorine inlets, and (b) recovering final product aqueous solution of ferric chloride from the base of the reaction zone.

Abstract: A method of removing silicon from a waste hydrochloric acid pickling solution is disclosed which comprises stirring the waste solution long enough to form a sludge having a particle size such that the sludge can be separated by a conventional means such as filtration through a filter of at least 0.1 .mu.m in pore diameter, centrifugation or sedimentation. The stirring period can be greatly reduced by adding to the waste pickling solution sludge recovered from an aged waste hydrochloric acid pickling solution or a carbonaceous material such as carbon black having hydrophilic groups on the surface. The sludge is also useful as a filter medium in filtration of the waste pickling solution to remove silicon. The present method can decrease the silicon content to 0.01% or less in terms of converted SiO.sub.2 /Fe.sub.2 O.sub.3 weight ratio.

Abstract: An improved method for producing aluminum titanate powder material for making aluminum titanate ceramics.

Abstract: A method for producing a powdered iron oxide comprises the steps of adjusting the pH of a crude iron chloride solution to 2.5-4.5; reducing the P content of the solution by mechanical stirring or air bubbling and filtering; and oxidizing the solution into a powdered iron oxide having a maximum P content of 0.005 wt. %. The P content of the solution may also be reduced by ultrafilter treatment. The soft ferrite made by using the powdered iron oxide by this process shows excellent magnetic properties.

Abstract: According to the subject method of refining a ferrous ion-containing acid solution, a metal selected from a group including Al, Cr, V, B, and Zn or an acid solution of that metal is added to a ferrous ion-containing acid solution, such as an acid solution which remains after steel is washed with an acid. The pH value of the acid solution is controlled to be within the range of 3.5 to 6 by adding an alkali liquid to the acid solution, whereby a hydroxide salt of the added metal is produced in the acid solution and the impurities in the acid solution are captured by the produced hydroxide salt. As a result, the impurities can be eliminated from the acid solution such that the Si component (e.g., SiO.sub.2) content in the acid solution is within the range of 2 to 3 ppm or less. Since the content of the other impurities such as Al, Ti, and Cr can also be reduced, a high-purity iron oxide can be obtained from the resultant acid solution.

Abstract: Process for the production of hydrated aluminae through the precipitation of aluminum hydroxide in a reactor by the reaction of an aluminum compound soluble in a polar solvent with a precipitating agent, also solubilized in the polar solvent, in constant conditions of pH, temperature, concentration and agitation; concentration of the suspension of precipitated aluminum hydroxide; crystallization in an alkaline pH, essentially constant; separation of the crystallized aluminum hydroxide, for later washing and drying. The product obtained is homogeneous and with excellent characteristics for utilization in the manufacturing of catalysts and catalytic supports. The process can be applied, advantageously, in the treatment of the acid waste from processes which utilize Friedel-Crafts type reactions, obtaining, in addition to the hydrated alumina, a liquid effluent with low metal contents.

Abstract: A method of processing waste solutions containing metal salts or complex involves applying ultra-sonic vibrations to a container in which the solution is placed and treating the solution or the generated misting therefrom to insure that the metallic ions remain behind and then finally exhausting the vapor through an activated charcoal filter to remove any organic contaminants and insure that the discharge is environmentally safe.

Abstract: The following inorganic compounds of iron, when added to Bayer process liquors, form a precipitate of the finely divided iron present in:A. Ferric oxide;B. Ferrous salts; orC. Ferrous salts in combination with ferric oxide.The precipitate is removed using a polymeric flocculating agent. This treatment reduces iron levels below those obtained using other iron removal treatments.

Abstract: A device for and method of working up etching and pickling liquids consisting of a vertical furnace having one or more vertical reaction spaces through which balls move at a maximum packing density.The furnace has a temperature gradient from the bottom (high) to the top (low). The reaction space and the balls consist of a material which is inert with respect to the liquid to be worked up. The liquid is introduced into the upper side of the furnace so that a film is formed in the heated surface of the balls. The salt dissolved in the liquid decomposes pyrolytically. The metal oxide is deposited on the surface of the balls and is removed therefrom after leaving the reaction space. The acid residue vapours are drained at the top and recovered in a separate absorber to the original pickling or etching acid.

Abstract: The invention relates to a process for the preparation of basic copper carbonate by reacting copper salts with alkali carbonate in aqueous solution at elevated temperatures and with stirring and subsequently isolating the copper carbonate. In this process, a waste solution from copper etching processes which contains hydrochloric acid and sodium chloride, is stirred into a 5 to 15 weight percent solution of alkali carbonate heated to 40.degree. to 70.degree. C., the pH of the solution not being allowed to fall below 6.5, and the precipitated basic copper carbonate is separated from the aqueous solution in a known manner. A light green, basic copper carbonate is obtained, which is free of copper chloride and copper oxide.

Abstract: A process for the treatment of a spent hydrochloric acid solution containing dissolved iron, zinc, and minor amounts of heavy metals to remove such dissolved metals from the solution, which process comprises contacting said solution with metallic iron in a first stage, whereby trivalent iron present in the solution is reduced to divalent iron and certain of said heavy metals may be reduced to elemental form, next, in a second stage, contacting said solution with metallic zinc, whereby any remaining heavy metals are reduced to elemental form, and then extracting zinc, as zinc chloride, from the resulting aqueous phase with an organic liquid containing a complexing agent for zinc chloride.

Abstract: A process for treating and recovering pickling waste liquids used for the pickling of stainless steel such as nitric-hydrofluoric acid, nitric acid, hydrochloric acid and, sulfuric acid is disclosed, which comprises recovering the nitric-hydrofluoric acid and the iron oxide or metallic ion from the waste liquids of nitric-hydrofluoric acid and nitric acid by two solvent extraction processes and recovering the Cr and Ni containing ferrite from the waste liquids of sulfuric acid or hydrochloric acid by a ferrite formation process. When the waste acid is sulfuric acid, gypsum of a high purity can be obtained.

Abstract: A process for production of metallic iron by heating ammonium iron fluoride or iron fluoride in hydrogen stream.

Abstract: A method for the regeneration of spent pickling acids. Said acid is mixed with such a minor quantity of a stronger acid that the losses of said stronger acid are compensated. The mixture obtained is stripped, whereby the weaker acids are vaporized. The vapor phase containing the weaker acids is passed to a condenser. The condensate obtained forms the regenerated pickling acid. The spent pickling acid can also be passed directly to an evaporator in which a solution containing a stronger acid is circulated. The vapor from the evaporator is passed to an absorption column and thereafter to a condenser, the regenerated acid being formed of the condensate from said condenser.

Abstract: A method of recovering hydrochloric acid from spent hydrochloric acid pickle liquor is used to increase the amount of hydrochloric acid recovered and to improve the form of the waste products for better handling and reduced energy costs. The waste pickle liquor from the pickle line is first concentrated before the liquor is reacted in a double exchange process with strong sulphuric acid. The concentrator separates the weak pickle into two streams consisting of an overhead vapor stream and an underflow of strong pickle liquor. The overhead vapor stream separates out hydrochloric acid by means of a fractionator with the underflow of strong pickle liquor being fed to the double exchanger reactor to be mixed with the sulphuric acid. The overhead from the reaction process which consists of hydrogen chloride and water vapor is condensed and made available for addition to the fractionated hydrogen chloride.

Abstract: The invention relates to the re-extraction of a metal from an organic extraction solution in which the metal is present as a metal chloride complex bonded to an extractant. The organic extraction solution is contacted with an aqueous solution, to transfer metal ions and chloride ions to the aqueous solution. Sulphuric acid is added to the aqueous solution, which is subsequently heated to drive off hydrogen chloride and water. Metal sulphate is removed from the acidified aqueous solution.

Abstract: A process for reclaiming pickling liquor acid from spent pickle liquor comprises injecting the spent liquor from a metal pickling process into a container having an upper section, a lower liquid holding section and a heating means. The spent pickle liquor in the container lower section is heated, and the water therein is vaporized and returned to the pickling process in a vapor state to be absorbed therein and provide heat thereto. A substantial portion of the unused acid is removed from the spent pickle liquor and is also returned to the pickling process without cooling.

Abstract: A process for treating an acid waste liquid containing Fe ions which has been used for acid washing of metallic materials or articles, comprising the first stage where an organic solvent (A) is added to the acid waste liquid to extract Fe ions, the second stage where an acid is added to the resulting acid waste liquid to convert chemical species of remaining metal salts and increase the hydrogen ion concentration followed by addition of an organic solvent (B) to recover the mineral acid of concern by extraction, the third stage where an organic solvent (C) is added to the resulting acid waste liquid to extract and recover other required mineral acids, and regenerating each of the organic solvents (A), (B) and (C) in respective stages.

Abstract: In pickling metal, such as iron, steel, special alloys, or the like, aqueous blends containing hydrofluoric acid and nitric acid are used as pickling solutions; resulting spent pickling solutions are evaporated under controlled conditions, such that the concentrate is supersaturated and contains a predetermined amount of iron; the concentrate is then partially cooled and transferred to a crystallization zone where, under controlled conditions, a crystalline precepitate is formed by cooling the concentrate in two phases; the resulting precipitate is then separated from its mother liquor, and the latter is recycled for use in pickling metals of the aforedescribed type.

Abstract: A method for selectively extracting metal values from manganese bearing ores such as marine nodules. The ore is initially leached to solubilize manganese and other desirable metals as nitrates. The resulting solution is then treated with manganous hydroxide to selectively precipitate metals such as copper, nickel and cobalt. The enriched mixture of metal hydroxides is separated from the manganese nitrate solution, which is decomposed to recover high purity MnO.sub.2.

Abstract: A process for regenerating waste acid, such as waste hydrochloric acid pickling liquor by producing aqueous hydrochloric acid of pickling concentration and generating iron oxide including that of pigment grade, comprises the steps of (1) concentrating the waste liquor, (2) reacting the concentrated liquor at a temperature below 1000.degree. F.

Abstract: A method and apparatus for producing pre metallic oxides by dissolving the metal or oxide in heated dilute hydrochloric acid to form metallic chloride in a water solution (which solution may instead, be a waste product from a steel strip pickling line), reacting said solution in a reactor in the presence of heated oxygen to form metal oxide, part of which oxide being carried over in vapor form to a variable throat venturi where it is redissolved and reintroduced into the reactor to insure that only low chloride oxide will be discharged as a product. The system operates under negative pressure to prevent leakage tendency of HCl to the outside atmosphere.

Abstract: A process for the thermal decomposition and conversion of metal chlorides to metal oxides in a fluidized bed wherein the fluidizing gas contains oxygen and the reaction temperature is maintained above the thermal decomposition temperature of the metal chloride but below the sintering temperature of the metal oxide thus produced. The gas velocity is determined by the critical relationship 0.34.rho..sup.0.9 .ltoreq. W.sub.G .ltoreq. 0.56.rho..sup.0.9 where W.sub.G is the approximate gas velocity through the fluidized bed chamber in the absence of the bed and .rho. is the density of the pure fluidized-bedmaterial (metal oxide). The height of the bed is also critical and should be that at which a critical pressure drop of 1200 to 2400 mm (water column) is obtained but at least 350 mm, measuring with the static or settled bed (nonfluidized).