Abstract: The present invention relates to storage-stable solutions of basic aluminium sulphate containing polynucleate aluminium hydroxide sulphate complexes of the formula[Al(OH).sub.x (SO.sub.4).sub.y (H.sub.2 O).sub.z ].sub.nin which x is 0.75-2.0; y is 0.5-1.12; 2x+y=3; and z is >>4, which solutions contain a stabilizing agent in the form of nitrilotriacetic acid, diethylene triaminopentaacetic acid and/or gallic acid.

Abstract: A process for producing basic aluminum sulfate of the general formulaAl(OH).sub.a (SO.sub.4).sub.b.nH.sub.2 Owherein a, b and n are positive numbers satisfying a+2b=3, 2.30.ltoreq.a.ltoreq.2.56, 0.22.ltoreq.b.ltoreq.0.35 and O.ltoreq.n.ltoreq.10, which comprises reacting a water-soluble basic aluminum salt of the general formulaAl(OH).sub.c X.sub.dwherein X represents a monovalent anion, and c and d are positive numbers satisfying c+d=3 and 0.5.ltoreq.c.ltoreq.2.55, with a water-soluble sulfuric acid salt in an aqueous medium at a temperature of less than 90.degree. C. This process gives novel basic aluminum sulfate which is either fibrous, spherical or prismatic depending upon the reaction conditions.

Abstract: An improved precipitation system is provided for the Bayer process production of alumina hydrate. In order to produce coarse and strong alumina hydrate at high yield, supersaturated Bayer process sodium aluminate liquor is seeded with a relatively small seed charge in a first precipitator at a relatively low temperature and the produced slurry is transferred to a second precipitator where without additional seeding, the solids content of the slurry is allowed to increase to about 250-700 g/l by accumulating solids in the line until the desired solids content is reached. After a suitable residence time, a coarse, strong product hydrate can be recovered in yields of or exceeding 80 g/l based on the alumina (Al.sub.2 O.sub.3) content of the supersaturated sodium aluminate liquor subjected to precipitation.

Abstract: A process is provided for preparing basic aluminum carbonate gels substantially free from foreign anions at a pH within the range from about 5.5 to about 7.0, according to the reactants used, and then converting such gels to high purity fibrous colloidal alumina monohydrate of the boehmite crystal lattice structure by hydrolysis with weak acids.

Abstract: Aluminum hydroxycarbonate gel is precipitated under highly homogeneous conditions by continuously introducing an aluminum salt solution and an alkaline-reacting carbonate and bicarbonate solution into a vigorously agitated reactor vessel and continuously withdrawing the reaction mixture.

Abstract: Crystalline 2-layer lithium aluminate, especially when carried in an ion exchange resin, is regenerated for use as an extractor for Li.sup.+ values in aqueous solution, said regeneration being done by using an aqueous wash containing at least about 800 ppm Li.sup.+ ion.

Abstract: The present invention relates to a process for stabilizing dehydrated magnesium chloride by coating with a material having a high degree of affinity for water. The coating operation is preferably carried out with magnesium oxide in a layer thickness of at least 0.1 mm, the magnesium oxide being hydroxylated by adding water during the coating operation.

Abstract: An aqueous slurry of a water-insoluble or slightly water-soluble metal hydroxide can be effectively filtrated and dehydrated by adding an anionic surfactant of the following formula (I):R--O--AO--.sub.n X (I)wherein R represents an alkyl or alkenyl group of 8-24 carbon atoms, A represents an alkyene group of 2-4 carbon atoms, X represents SO.sub.3 M (M being H, K, Na or NH.sub.4), PO.sub.3 M (M being K or Na) or CH.sub.2 COOM (M being K or Na), and n represents an interger of 1-100,to the aqueous slurry of the metal hydroxide or to the washing water.

Abstract: Coarse grains of aluminum hydroxide having high resistance to disintegration to powder in a calcination step are continuously produced from a supersaturated sodium aluminate solution of the Bayer process through(1) a first precipitation step of adding recycle seed aluminum hydroxide to a supersaturated sodium aluminate solution having a molar ratio of Na.sub.2 O as caustic soda to Al.sub.2 O.sub.3 in solution of less than 1.8 supplied to a precipitation tank of substantially complete mixing type in a ratio of 30-150 kg of the recycle seed to 1 m.sup.3 of the solution, thereby partially decomposing the seed-added solution until the molar ratio of the solution reaches 2.0-2.4 while keeping the solution at 65.degree.-80.degree. C.

Abstract: Coarse grains of aluminum hydroxide are economically produced in a high yield from sodium aluminate solution by dividing supersaturated sodium aluminate solution being prepared by the Bayer process and having a molar ratio of Na.sub.2 O as caustic soda to Al.sub.2 O.sub.3 in solution of less than 1.8 into two streams, adding a portion of recycle seed aluminum hydroxide and fine grains of aluminum hydroxide as seed to one of the streams of sodium aluminate solution, partially decomposing the sodium aluminate solution until the molar ratio of the sodium solution reaches 1.8-2.6, adding to the resulting partially decomposed sodium aluminate slurry the other stream of sodium aluminate solution, which has been cooled to a temperature low enough to lower the temperature of the partially decomposed sodium aluminate slurry by at least 3.degree. C.

Abstract: A precipitation system is provided for the production of strong, coarse alumina hydrate (Al.sub.2 O.sub.3.3H.sub.2 O) from Bayer process aluminate liquors. In the system three distinct, but interconnected processing stages are utilized which comprise an agglomeration stage, a growth stage and a seed generation stage. In the agglomeration stage hydrate particles agglomerate to form coarse particles; in the growth stage these particles grow and acquire strength; while in the seed generation stage alumina hydrate seed is generated to be used in the agglomeration and growth stages.The precipitation system combines the advantages of both the American and European Bayer processes in that it results in the production of a strong, coarse product hydrate and an increased yield.

Abstract: A method of purifying waste water with treated aluminum oxide. The method comprises contacting the waste water with Al.sub.2 O.sub.3 which has been treated with ions which when incorporated in the crystal lattice of the Al.sub.2 O.sub.3 are capable of delaying crystallization of the gamma phase of the Al.sub.2 O.sub.3 or with the salts of said ions.In one embodiment, the Al.sub.2 O.sub.3 is artificially synthesized and the treatment comprises incorporating the ions, which may be either anions or cations, in the course of the synthesis.Alternatively, the Al.sub.2 O.sub.3 may be treated by subjecting the Al.sub.2 O.sub.3 to a surface treatment with ions capable of delaying crystallization of the gamma phase or the salts thereof.In yet another embodiment, the Al.sub.2 O.sub.3 may be doped with CO.sub.2.

Abstract: There is disclosed a process for receiving, storing and handling aluminum hydroxide wet hydrate, wherein the aluminum hydroxide wet hydrate is unloaded, optionally in batches, by means of a dumping means, e.g., a dump truck into a hopper which is equipped with a conveying means, e.g., a plate conveyor, the aluminum hydroxide wet hydrate supplied by means of a transporting apparatus, e.g., a double belt vertical conveyor, to a weighing means, e.g., a conveyor-type weigher and weighed, subsequently supplied to an aluminum hydroxide wet hydrate suspension tank, mixing the aluminum hydroxide wet hydrate in the tank with the amount of aqueous sodium hydroxide needed to produce a suspension of the aluminum hydroxide wet hydrate and producing a pumpable and meterable suspension of the aluminum hydroxide wet hydrate by heating to a temperature between 20.degree. and 100.degree. C. with the aid of a heating element and a stirrer.

Abstract: A process is disclosed for preparation of an amorphous polyaluminum sulfate composition of the formulaAl(OH).sub.x (SO.sub.4).sub.y (H.sub.2 PO.sub.4).sub.z (H.sub.2 O).sub.wwhereinx is about 0.75 to 1.5y is about 0.7 to 1.07z is about 0 to 0.2w is about 2.0 to 4.2with the proviso that the sum x+2y+z is 3. Water is withdrawn from a fairly fresh polyaluminum sulfate solution having the formulaAl(OH).sub.x' (SO.sub.4).sub.y' (H.sub.2 PO.sub.4).sub.z' (H.sub.2 O).sub.w'whereinx' is about 0.75 to 1.5y' is about 0.7 to 1.07z' is about 0 to 0.2w' is about 18 to 65with the proviso that the sum x'+2y'+z' is 3. The amorphous composition is useful for reconstitution with water to prepare a coagulant solution.

Abstract: Process for the manufacture of coarse aluminum hydroxide, containing a maximum of 15 weight percent of the particles in a particle size under 45 micrometers, with a productivity that may be higher than 60 grams of precipitated Al.sub.2 O.sub.3.The process consists of a decomposition in two stages (an agglomeration phase and a growth phase); each stage proceeding within defined temperature ranges with seed material of different constitution. The first (fine) seed amount is added at the start of the decomposition in such an amount, that the ratio of the supersaturation of the aluminate liquor to the surface area of the seed hydroxide per liter of the aluminate liquor presented for decomposition exhibits a value of 7 to 25 grams per square meter. The process exhibits the advantage of the high productivity of the so-called European process and the advantage of the so-called American process by obtaining a coarse product hydroxide.

Abstract: A process for alunite ore treatment which comprises roasting alunite in the presence of oxygen at a temperature of from 580.degree. to 620.degree. C. for 1 to 3 hours, decomposing the roasted alunite by exposure to reducing agents at a temperature of from 580.degree. to 620.degree. C., subjecting the reduced alunite to hydrochemical treatment by use of a sodium hydroxide solution of concentration from 100 to 150 g/lit in terms of Na.sub.2 O, decomposing the resultant aluminate liquor, with the aluminum hydroxide component precipitating out, and finally, washing and baking the aluminum hydroxide precipitate to obtain same as an end product. The invention provides a comprehensive method of treatment of alunite ores the associated rock whereof comprises silica in the form of opal and chalcedony earlier believed to be refractory to comprehensive treatment by alkaline methods.

Abstract: A process for producing aluminum hydroxide gels substantially free of sodium ions involves a heterogeneous reaction between an aqueous solution of a water soluble aluminum salt and an aqueous slurry of a water soluble alkaline earth carbonate.

Abstract: Aluminum may be recovered from various raw materials including kaolinite, alunite, coal ash and slag, and both raw and spent oil shale, by contacting such materials with an aqueous solution of hydrofluoric acid, followed by removal of the insoluble residues remaining suspended in solution and the precipitation of hydrated aluminum hydroxide from the clear solution by basification with an alkaline agent.

Abstract: An improvement in the process for the recovery of aluminum from alunite in which the alunite in particulate form is dehydrated, sulfur and alkali metal compounds removed from the dehydrated ore leaving a particulate residue containing aluminum values, the residue digested with at least one alkali metal hydroxide to convert the aluminum values to soluble aluminates, silicon removed from the soluble aluminate solution, and aluminum values precipitated from the aluminate solution, the improvement comprising: multiple stage digestion of the particulate residue accomplished by dividing the particulate residue into two fractions, digesting one fraction first and using the first stage liquor from the first digestion step to digest the remaining fraction. The fraction digested first may be the one having the smaller particle size, or the one having the larger particle size.

Abstract: Alumina dust, particularly partially calcined alumina dust, is coarsened by forming an aqueous admixture or slurry comprising the alumina dust and finely divided calcium carbonate and introducing the resulting aqueous admixture or slurry into Bayer pregnant liquor and precipitating alumina trihydrate from the resulting Bayer pregnant liquor.

Abstract: The invention relates to a process for the purification of water intended for human consumption or industrial use, and a process for the clarification of urban or industrial waste water, by means of a solution of a polymeric aluminum hydroxide which is prepared immediately before its use by adding an alkaline or alkaline-earth hydroxide to an aluminum salt. The conditions of preparation are chosen so as to prevent the formation of monomeric aluminum hydroxide.

Abstract: Aluminate mother liquor is passed countercurrent to the direction of feed of aluminum hydroxide crystals through at least two stages, each of which has a lower turbulent zone with a high suspension density and which is agitated under conditions which assure particle growth via crystal growth and an upper non-turbulent, stagnant liquid layer from which most crystals settle back into the respective lower turbulent zone. The suspension density in the stages is maintained at a constant level by sending crystal suspension from the lower turbulent zone in all the precipitation stages but the first to the preceding stage. Mother liquor is removed from the upper stagnant zone of all stages but the last stage and sent to the respective following stages. Coarse crystal suspension is removed from the turbulent zone of the first stage for separation of the crystals for further processing, while the mother liquor is returned to the system.

Abstract: The preparation of a material consisting essentially or largely of aluminum hydroxychlorides having the general formula Al.sub.2 (OH).sub.X Cl.sub.6.sub.-X, in which X is a value up to 5 or more and obtained by reacting active alumina, secured by partial dehydration of hydrates of alumina, with hydrochloric acid or aluminum chloride in which the active alumina has a specific surface area of at least 200 m.sup.2 /g.

Abstract: This invention relates to a method for recovering aluminum hydroxide from alunite ore by roasting the ore to remove water of hydration, roasting it again in a reducing atmosphere to remove sulfate, roasting a third time in an oxidizing atmosphere to convert any sulfides formed in the second roast, leaching with a weak base, leaching with water to remove potassium and sulfate, extracting the aluminum content with a mixture of sodium hydroxide and potassium hydroxide, removing contaminant silica from the leach solution, and precipitating aluminum hydroxide by cooling and seeding the solution.

Abstract: Ammonium hydroxide is added to a mixture of high-temperature, high-pressure geothermal steam and brine to raise the pH of the brine to between 6.0 and 7.0 and precipitate out a gelatinous sludge of aluminum and iron hydroxides. The hydroxide sludge is suspended in the brine and sweeps out enough dissolved silica so that the temperature and pressure of the brine can be reduced with little, if any, formation of silica scale. Various metals and ammonium hydroxide may then be recovered from the brine, the ammonium hydroxide being recycled in the process.

Abstract: Aluminum oxide having a sodium oxide content after calcination of less than 0.1% by weight is continuously precipitated as aluminum hydroxide from a Bayer process liquor by a controlled slow precipitation. The controlled, slow precipitation rate required to create a low soda product is achieved by controlling the residence time of liquor in the precipitation vessel so as to provide a constant, low ratio of aluminum oxide to sodium oxide. Residence time control in a Bayer process plant is achieved by controlling green liquor flow rate to the tank, or by sizing the tank for a constant flow. The use of heavy seed charges to increase the seed surface area permits the production of a low soda product at a faster precipitation rate.

Abstract: Water dispersible aluminum hydroxide is prepared by treating an acid dispersible aluminum hydroxide with 1 to 9 weight % of a gaseous acid.

Abstract: A process for the production of monobasic potassium phosphate from wet process phosphoric acid and potassium sulfate by ion exchange. The application of the process is the production of monobasic potassium phosphate by ion exchange from wet phosphoric acid produced by the reaction of sulfuric acid on apatite rock and by-product potassium sulfate from processes for the recovery of aluminum from alunite.

Abstract: A method for dehydrating alunite ore prior to further processing to recover metals therefrom, comprising exposing the ore in particulate form to burning coal as the heat supply in a fluidized bed fluidized with an oxygen containing gas. The invention is illustrated by the removal of water from alunite ore prior to further processing the ore to recover aluminum.

Abstract: An improvement in processes for recovering aluminum from alunite ore which processes include roasting the ore to remove water of hydration, removing sulfur and potassium compounds from the roasted ore by a procedure including a final leaching step resulting in a residue and a solution containing potassium sulfate, effecting partial recovery of potassium sulfate from the solution by crystallization with some potassium sulfate being bled off from the mother liquor, converting aluminum values in the residue to alkali metal aluminates by digesting the residue with alkali metal hydroxide including a substantial amount of sodium hydroxide, removing silicon from the alkali metal aluminates leaving a waste desilication product, recovering aluminum values from the desilicated aluminates by precipitation, circulating the mother liquor from the precipitation step to digestion as contaminated sodium hydroxide is bled off, the improvement which comprises enhancing the economics of the overall process by introducing therei

Abstract: A method for processing alunite consisting in that alunite ore is treated with a solution of caustic alkalis at a maximum temperature of 60.degree.C, and a solid residue resulting from the above operation and containing largely potassium and sodium sulphates, is washed with hot water. As a result, potassium and sodium sulphates are dissolved in the wash water, and potassium sulphate is isolated by the action of a caustic-potash solution. The method enables losses of alkalis and aluminium during processing alunite ores containing active forms of silicon compounds to be much reduced, which compound when treating alunite ores with a solution of caustic alkalis, are liable to form insoluble aluminosilicates which are discarded into slime and thus lost together therewith when the latter is separated from the process solution.

Abstract: Sodium carbonate is formed by reaction between particulate sodium aluminate in solid form, and carbon dioxide and water vapor in gaseous form. The sodium carbonate is readily separated from by-product hydrated alumina for recovery in pure form, or the dry product of the reaction may be employed directly where a dry sodium carbonate feed is desired, with the hydrated alumina being filtered off prior to further processing.

Abstract: A process for the extraction and recovery of aluminum from aluminum-containing raw materials by contacting said raw materials with fruit juices and complexing organic acids.

Abstract: A process for the production of pure alumina from alumina and silicate containing raw materials comprising feeding said raw material into the top of an acid resistant leaching tower; continuously feeding a leaching liquor containing hydrochloric acid into the bottom of said leaching tower, continuously flowing said leaching liquor upward through said raw material to leach out the alumina as a solution of aluminum chloride, withdrawing said solution enriched in aluminum chloride toward the top of said tower zone; withdrawing said raw material solid residue from the bottom of said tower zone to convey said solid residue from said leaching tower into a separation zone at a level higher than the level of said leaching tower; and separating said solid residue from said carrier liquid in said separation zone.Apparatus for producing alumina according to this method includes the corresponding means.