Abstract: A process for the precipitation of aluminum trihydroxide from a supersaturated sodium aluminate solution, comprising the steps of(a) supplying a stream of supersaturated sodium aluminate solution and a first stream of aluminum trihydroxide particles as seed particles to a first reaction circuit,(b) maintaining the sodium aluminate stream containing the stream of seed particles in the first reaction circuit under conditions mainly resulting in precipitation and agglomeration of aluminum trihydroxide,(c) passing the stream thus obtained to a second reaction circuit in which the stream is maintained under conditions mainly resulting in precipitation and growth of aluminum trihydroxide particles,(d) passing the stream obtained in the second reaction circuit to a separation/classification unit to separate the stream into a first aluminum trihydroxide product stream comprising the coarser particle size portion, a second aluminum trihydroxide product stream comprising the finer particle size portion and a spent liqu

Abstract: An improved salt basket for dewatering solids, particularly salts resulting from evaporation of industrial wastewaters. The salt basket system includes a pressurizable vessel having a screen floor situated above a bottom liquid collection head, an inlet for the brine/solids slurry from which solids are to be separated and dried, an inlet for air, an inlet for steam (the latter two inlets may be combined, where convenient), an inlet for solids free feed, and a drain outlet (these two may be combined where convenient into a combination feed/drain connection). Preferably, an automated system for introducing feed brine and for removing the solids product is provided. For safety, a pivotally attached lower door has a hydraulic failsafe closure mechanism and locking safety latches to prevent the door from inadvertently opening.

Abstract: A potassium chloride mixture with grains of different sizes is extracted in a first stage with an unsaturated solution at an elevated temperature, whereby the finest grains are completely dissolved and the coarse proportions are caused to start dissolution, the purified medium fraction is transported into a second process stage and the previously dissolved amount of KCl is crystallized there onto the purified grains at a lower temperature, forming a product of high purity with a balanced grain size and a narrow grain spectrum.

Abstract: Crystalline MgCl.sub.2 particulates, exhibiting the morphology of substantially regular polyhedra having an even number of from 10 to 18 face surfaces, are well suited as support substrate for olefin polymerization catalysts.

Abstract: A large size, small surface area, granular crystalline potassium bicarbonate product suitable for application as an active ingredient in pharmaceutical oral unit dosage forms useful for the treatment of various degenerative bone and cardiovascular diseases, particularly osteoporosis or hypertension, comprising potassium bicarbonate crystals having a mean particle size of at least 350 microns and a specific B.E.T. surface area less than 0.02 m.sup.2 /gram. A process for preparing such product is further provided, in which a solution of potassium bicarbonate is fed to a slurry of potassium bicarbonate crystals in a crystallizer and the temperatures and concentrations of the potassium bicarbonate in the feed solution and the crystallizer slurry are so regulated, and the residence time and degree of agitation in the crystallizer are so controlled, that the desired large size, small surface area potassium bicarbonate crystals are produced.

Abstract: A method of manufacture including bringing seed and aluminum hydroxide together in an aqueous medium and hydrothermally digesting for producing boehmite at the expense of the aluminum hydroxide.

Abstract: A method for preparing an oriented and textured magnetic compound, comprising the steps of preparing a composition at a temperature such that it comprises crystallites of the compound in the presence of a liquid; subjecting the composition to a magnetic force producing crystallite sedimentation; cooling down the composition in the presence of a magnetic force while applying a suitable temperature gradient for improving the development of a desired texture in the sedimentation area.

Abstract: In a process for precipitating alumina hydrate from a stream of Bayer process liquor, wherein the stream is first divided into a major portion and a minor portion, the minor portion fed to an agglomeration stage and seeded with fine seed to induce precipitation and formation of a slurry, and the major portion cooled and charged with coarse seed and directed to a growth stage to induce formation of alumina hydrate product, the steps of: separating solids from the minor portion after formation of the slurry; cooling, to a temperature of between about 45.degree. C. and about 60.degree. C., the liquid remaining after separating solids from the slurry formed in the agglomeration stage; adding an amount of coarse seed to the remaining liquid to generate a slurry of fresh hydrate nuclei; and recombining the slurry of fresh hydrate nuclei with the major portion of the stream.

Abstract: An improved process for precipitating alumina from Bayer process liquors is disclosed. The process involves dividing an incoming pregnant liquor stream into a minor portion of about 10 to about 25% by volume of the total incoming pregnant liquor stream, and directing that stream into a series of small tanks where the minor stream is permitted to agglomerate. Fine aluminum hydroxide seed having a median particle size of between about 30 and about 60 microns is added to this stream. The slurry resulting from the agglomeration stage is then directed to a set of larger vessels in which the growth stage will take place. At this point, the remaining portion of the pregnant liquor is combined with the slurry resulting from the agglomeration stage. A coarse seed charge of about 150 to about 600 grams/liter of seed having a median particle size of between about 80 and about 100 microns is charged into the second set of vessels.

Abstract: Crystals are grown in a tank which is divided by a baffle into a crystal growth region above the baffle and a plenum region below the baffle. A turbine blade or stirring wheel is positioned in a turbine tube which extends through the baffle to generate a flow of solution from the crystal growing region to the plenum region. The solution is pressurized as it flows into the plenum region. The pressurized solution flows back to the crystal growing region through return flow tubes extending through the baffle. Growing crystals are positioned near the ends of the return flow tubes to receive a direct flow of solution.

Abstract: A mass constituted by glucose syrup and anhydrous dextrose crystals is led to pass through from top to bottom and with malaxation of crystallization zone 1 of axis preferably substantially vertical in which said mass is subject to a temperature gradient globally decreasing by 0.2.degree. to 2.degree. C./hour from top to bottom possibly modulated, said zone being supplied through pipe 2 with glucose syrup and through pipe 7 with mass subject to crystallization M taken up at 8 and recycled at 9.

Abstract: A mass constituted by glucose syrup and anhydrous dextrose crystals is led to pass through from top to bottom and with malaxation a crystallization zone 1 of axis preferably substantially vertical in which said mass is subject to a temperature gradient globally decreasing by 0.2.degree. to 2.degree. C./hour from top to bottom possibly modulated, said zone being supplied through pipe 2 with glucose syrup and through pipe 7 with mass subject to crystallization M taken up at 8 and recycled at 9.

Abstract: A counter-current process for purifying chemicals using cyrstal purification. The unit process has a purification and recovery section which contain substantially identical stages. In operation, the unit process purifies the chemical by utilizing sequential recrystallizer. The size and purity of the crystals increases from the last recrystallizer in the recovery section through each subsequent stage to the last recrystallizer in the purification section.

Abstract: A process for reducing sulfate ion concentrations in an alkali metal halide brine to be electrolyzed in an electrolytic cell comprises feeding the alkali metal halide brines to a reaction zone containing a slurry of gypsum crystals having a concentration of at least 5 weight percent of solids to form a brine-containing slurry. An aqueous solution of a brine soluble calcium salt is admixed with the brine-containing slurry in an amount sufficient to reduce the sulfate ion concentration to a desired level. The brine-containing slurry is agitated at a pumping velocity of at least about 1.0 meters per second to release solution supersaturation by gypsum crystal formation.

Abstract: Asbestiform crystalline calcium sodium metaphosphate fibers are prepared by (a) forming a homogeneous melt of substantially crystalline calcium sodium metaphosphate having a composition on a dry basis equivalent to a CaO/Na.sub.2 O/P.sub.2 O.sub.5 mol percent ratio of about 29.0-34.0/16.0-18.0/50.0-53.0 and a degree of crystallinity from about 60% to about 75% as determined from density and differential thermal analysis measurements, (b) supercooling the homogeneous melt, (c) seeding the supercool melt with calcium sodium metaphosphate crystals, (d) maintaining the seeded supercooled melt at the seeding temperature under isothermal conditions for a time sufficient to form crystalline blocks of calcium sodium metaphosphate, and (e) fiberizing the crystalline blocks.

Abstract: Process for continuous crystallization of a liquid mixture in which the mixture is led through a cascade of cooling sections. The temperature in the first section is such that a part of the mixture crystallizes, the temperature in each succeeding section is lower than in the preceding section. The temperature in the last section is such that not the whole of the liquid mixture solidifies. The crystals kept suspended in the liquid are led through the cascade. In one section, not being the last one, the crystal and liquid flow is divided in two flows. One flow mainly formed by the crystals, the other by the liquid. A portion of the divided flow is recycled to the dividing section to keep the crystal volume fraction at a desired value.

Abstract: The invention concerns a method and apparatus for decomposing a sodium aluminate liquor supersaturated with alumina, obtained from alkaline action on bauxite by the Bayer process, decomposition being initiated by introduction of alumina trihydrate seed to trigger the decomposition, thereby forming a suspension. In this process the suspension is fed in at the top of a non-agitated reactor described as a "decomposer", and removed from the bottom of the decomposer; the speed at which the suspension moves downwardly is regulated at 1.5 to 10 meters per hour. The apparatus comprises a cylindrical-conical reactor which is fitted with an arrangement for feeding in the suspension at the top, and with an arrangement for taking out the suspension at the bottom. In one embodiment of the apparatus the suspension is taken from the base of the decomposer through an internal tube, with air injected into the bottom of it, is raised to the level of the top of the decomposer and is then sent downstream.

Abstract: The present invention relates to the processing of phosphoric acid by crystallization starting with phosphoric acid and adding relatively large amounts of fine, relatively pure seed crystals to acid which has been cooled to supersaturated conditions. Crystallization thereafter proceeds under conditions which substantially favor growth on the seeds which are added and disfavor secondary nucleation. The present invention particularly describes a seed crystal generator for use in the foregoing process in which relatively high purity phosphoric acid, containing 60% to 66% P.sub.2 O.sub.5 is cooled to a temperature of at least 5.degree. to 10.degree. C. below zero and thereafter nucleated under agitation for less than ten minutes in a small crystallizing vessel.

Abstract: The present invention relates to the processing of phosphoric acid by crystallization. Wet-process phosphoric acid is purified by cooling it to supersaturated conditions and adding relatively large amounts of fine, relatively pure seed crystal. Crystallization thereafter proceeds under conditions which substantially favor crystal growth on the seeds which are added and disfavor secondary nucleation. To prevent the crystallizing magma from reaching a viscosity which would render further processing difficult, the present invention provides for recycling raffinate in an amount sufficient to maintain the solids content of the crystallizing magma below about 40%.

Abstract: The present invention discloses a new method for obtaining a crystallized phosphoric acid of relatively high purity starting with conventional phosphoric acid. The new method is based on crystallization of orthophosphoric acid hemihydrate from the phosphoric acid. Massive nucleation which would lead to the formation of unprocessable masses is avoided in the new method by providing unusually large amounts of fine relatively pure seed crystals of orthophosphoric acid hemihydrate and operating the crystallization process under conditions which favor crystal growth on the seed crystals and disfavor the occurrence of secondary nucleation. To prevent the crystallizing magma from reaching a viscosity which would render further processing difficult the present invention provides for recycling raffinate in an amount sufficient to maintain the solids content of the crystallizing magma below about 40%.

Abstract: The invention concerns a process for the precipitation of aluminium hydroxide by seeding in two phases, which is intended to produce at a high level of productivity alumina with large grains, referred to as `sandy coarse`, by precipitation in a succession of tanks in cascade relationship of a supersaturated solution of sodium aluminate coming from alkaline attack on bauxite in accordance with the BAYER process. The process comprises three stages:in the first agglomeration stage, the supersaturated aluminate liquor is introduce into the tank, with an equivalent amount of terms of Na.sub.2 O of between 110 and 175 g/liter, at a temperature of between 65.degree. and 80.degree. C.

Abstract: Apparatus and a method for separating gases and vapors from a geopressure or hydropressured brine without allowing precipitation of scale deposits on the walls of vessels and pipes. The apparatus includes a reactor having an inlet pipe provided with a Venturi throat and an expansion nozzle coupled with the throat to depressurize the brine to cause separation of the gases and vapors from the liquid and solid fractions of the brine. The gases and vapors travel out of the reactor through a central pipe extending downwardly and through the reactor. The brine in the form of a slurry gravitates in the reactor toward a first outlet pipe while clarified brine rises past an internal baffle and leaves the reactor through a second outlet pipe.

Abstract: A method for treating in counter current of suspended particles with a liquid, whereby the particles and the liquid are transferred in opposite directions through a contact zone which, at some places, spaced in axial direction, is stirred in planes perpendicular to the center line of the contact zone, in which the contact zone is one continuous space and that the volume fraction of the solid matter in the contact zone is maintained at a value between 0.20 and 0.55.

Abstract: Substantially pure boehmite is produced by heating an aqueous sodium aluminate solution to a temperature of about 115.degree.-145.degree. C., preferably about 120.degree.-130.degree. C., treating the heated solution with alumina seed material and separating a boehmite precipitate from the solution. A particularly preferred seed material is boehmite gel.

Abstract: A process for the production of aluminum trihydroxide having controlled median diameter of 2 to 100 microns, with a unimodal distribution and minimum deviation, by decomposing a hot supersaturated sodium aluminate solution in the presence of seed aluminum trihydroxide, separating the resultant solid and liquid phases and recovering the solid phase constituted by precipitated aluminum trihydroxide. The process comprises grinding aluminum trihydroxide until the aluminum trihydroxide has a specific BET surface area of at least 1 m.sup.2 /g, introducing the ground aluminum trihydroxide into a hot fraction of the supersaturated sodium aluminate solution to precipitate trihydroxide seed and then decomposing the remaining fraction of the supersaturated sodium alimuniate solution in the presence of the seed. This decomposition leads to the precipitation of aluminum trihydroxide having the required median diameter.

Abstract: Disclosed is a process for producing finely divided dispersions of metal oxides and/or metal hydroxides. A supersaturated sodium aluminate liquor containing dissolved aluminum hydroxide is seeded with particles of at least one metal oxide and/or metal hydroxide. The liquor is subjected to predetermined crystallization conditions to form a crystallized solid. The crystallized solid is then separated from the liquor and dried.

Abstract: A process for the production of aluminum trihydroxide having a controlled median diameter of less than 4 microns, with a unimodal distribution and minimum deviation. The process comprises grinding aluminum trihydroxide until the aluminum trihydroxide has a specific BET surface area of at least 8 m.sup.2 /g, adding the ground aluminum trihydroxide to a sodium aluminate solution, and then decomposing the solution to precipitate aluminum trihydroxide having the required median diameter.

Abstract: Separating Ca(NO.sub.3).sub.2.4H.sub.2 O from a nitrophosphate digestion liquor by crystallization, wherein Ca(NO.sub.3).sub.2.4H.sub.2 O seeding material with a particle size smaller than 100 .mu.m is added to this liquor at a temperature of 0.degree.,1.degree.-2.degree. C. lower than the saturation temperature, the resulting liquor is batchwise cooled, and the Ca(NO.sub.3).sub.2.4H.sub.2 O crystallized out is separated from the cooled liquor.The Ca(NO.sub.3 ).sub.2.4H.sub.2 O is substantially crystallized out without excessive cooling as very coarse and uniform particles which can be easily separated out.

Abstract: Finely divided alumina, recovered from the dust recovery systems of alumina hydrate calcination facilities, is employed as seed for the precipitation of alumina hydrate from pregnant Bayer process liquors. The finely divided alumina dust can either be used as seed in as-is condition, or, if desired, agglomerated to coarse and strong particles prior to use as seed. Agglomeration is accomplished by combining the dust in a predetermined weight ratio with alumina trihydrate seed under controlled conditions. The process allows the utilization of an otherwise undesirable and unacceptable by-product of alumina hydrate calcination.

Abstract: A system for the precipitation of Al(OH).sub.3 from green liquor is provided which comprises process and apparatus for feeding the green liquor into the bottom of a chamber containing a supersaturated solution of alumina and Al(OH).sub.3 seed particles. The flow of green liquor into the bottom of the chamber is maintained at a rate sufficient to suspend the seed particles in the chamber with minimum turbulence so that the liquor is in approximately plug flow. As Al(OH).sub.3 precipitates on the seed particles, the particles grow larger and gradually move to the bottom of the chamber where they are removed. The solution, somewhat depleted with respect to Al.sub.2 O.sub.3, overflows the chamber to return to the process.

Abstract: In a gradient process of growing crystals from liquid media, the need for mechanical seed holders is eliminated in that a solvent is used which at the instantaneous temperature and under the instantaneous pressure employed in the growing process has a density which is equal or approximately equal to the density of the crystal or crystals which is or are being grown.

Abstract: Process for recovering coarsely crystalline alumina hydrate from bauxite according to the Bayer process wherein, in the presence of fine seed crystals, agglomerates are initially formed in a supersaturated sodium aluminate solution at 80.degree. to 65.degree. C. The agglomerates are then conducted through a first cascade of crystallizers and, after cooling to 55.degree. to 45.degree. C., through a second crystalizer cascade. A crystal suspension is extracted from the last crystallizer of the second crystallizer cascade and fractionated into fine seed crystals and coarse product crystals.

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 mixture of an alkali carbonate solvent salt, titanium oxide, an alkaline earth reactant selected from the group consisting of barium oxide, strontium oxide and mixtures thereof, and alkaline earth titanate seed is heated to melt the carbonate salt solvent in which the titanium oxide and alkaline earth reactant dissolve and react precipitating a titanate selected from the group consisting of barium titanate, strontium titanate and mixtures or solutions thereof onto said titanate seed producing large crystal sized powder, said titanate seed not differing significantly in chemical composition from the titanate being precipitated thereon.

Abstract: A liquid melt becomes converted to crystalline form at a particular temperature either spontaneously or when artificially nucleated. The liquid releases heat at crystallization. If the liquid is in a supercooled state when it begins to crystallize, its temperature will rise from the particular temperature at which it is nucleated.Another liquid material is mixed with the liquid to be crystallized. The liquid additive has properties of forming a metastable solid together with the crystallizing material. When the liquid additive exsolves, the crystalline aggregate is weakened and is easily decomposed into fragments of small size. The liquid additive materials may include monohydric alcohols, diols and triols. The liquid additive material may be included in the liquid to be crystallized, in small amounts, amounts to two percent (2%) to five percent (5%) being typical.

Abstract: To increase the percentage of crystallized lactose obtained from lactoserum substantially without noticeably increasing investment costs or energy consumption, the first phase of crystallization is effectuated in a continuous crystallization stage wherein seeds of crystallization are added to the lactoserum to initiate crystallization, the lactoserum is concentrated, the concentrated lactoserum is brought to a supersaturated state and maintained at this stage by evaporation to obtain a mixture of mother liquor and lactose crystals, which is subjected to two centrifugal drying stages to obtain a first portion of large lactose crystals and a second portion of such crystals grown by cooling.

Abstract: A reversible liquid/solid phase change composition comprising hydrated Mg(NO.sub.3).sub.2 /MgCl.sub.2, and one or more of Sr(OH).sub.2, Ca(OH).sub.2, CaO or BaO, added to the composition in an effective amount to suppress supercooling of the Mg(NO.sub.3).sub.2 /MgCl.sub.2 liquid phase.

Abstract: Heterogenous nucleation on a seed material is promoted in the removal of phosphate from water by contacting the water with the seed material in a bed of grains of the seed material which bed is fluidized and kept in fluidization by the water stream itself, while the introduction of the reagent or reagents is effected so as to have a substantially complete heterogenous nucleation take place on the seed material.

Abstract: Rapid recovery of molybdenum from an acid solution containing dissolved molybdenum is accomplished by using a multiple batch method. A first batch of ammonium molybdate precipitate is formed by diluting a first portion of acid with 1.5 times that volume of water, adding anhydrous ammonia, and seeding with ammonium molybdate particles while maintaining a temperature between 90.degree. C. and boiling. Subsequent batches of precipitate are formed by dissolving the previous precipitate in additional acid, similarly diluting as above, and adding anhydrous ammonia while maintaining temperature as above. All precipitates are coarse and fast settling.

Abstract: Phosphosiderite, FePO.sub.4.2H.sub.2 O, is prepared in high yield from molten Fe(NO.sub.3).sub.3.9H.sub.2 O and H.sub.3 PO.sub.4 using a phosphosiderite seed for initiation of precipitation and crystallization.

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: Disclosed is a granulating process which comprises the steps of providing a plurality of spouted bed granulation zones arranged in series and one or more fluidizing zones for cooling and drying purposes each disposed between two adjacent ones of the granulation zones, introducing priming granules of a particulate material into the first-stage granulation zone while spraying thereinto an adherent and solidifiable liquid together with a gas stream to enlarge the priming granules, cooling and drying the enlarged granules in the succeeding fluidizing zone, passing the resulting granules through the other granulation zones and fluidizing zones successively, and withdrawing the granules enlarged to a desired particle size from the last-stage granulation zone. Also disclosed is an apparatus for carrying out this granulating process.

Abstract: A reversible liquid/solid phase change composition comprising hydrated MgCl.sub.2 and one or more of Ba(OH).sub.2, Sr(OH).sub.2, CaO, SrCO.sub.3, BaO, Ca(OH).sub.2, Mg(OH).sub.2, MgO, Na.sub.3 AlF.sub.6 or CaC.sub.2 O.sub.4, added to the composition in an effective amount to suppress supercooling of the MgCl.sub.2 liquid phase.

Abstract: A process for the continuous crystallization of at least one crystallizable material from a solution wherein a series of crystallization stages are utilized, with partial crystallization taking place in each stage. The process includes the classification of partially crystallized suspension between each stage, and the suspension from the final stage is passed to a separator wherein it is separated into a concentrated suspension containing crystals and a spent liquor, the concentrated suspension being returned to the final stage and the spent liquor being discharged. Product crystals are taken from the first stage of the series.

Abstract: A process for the continuous crystallization of at least one crystallizable material from a solution wherein a series of crystallization stages are utilized, with partial crystallization taking place in each stage. The process includes the classification of partially crystallized suspension between each stage, and the suspension from the final stage is passed to a separator wherein it is separated into a concentrated suspension containing crystals and a spent liquor, the concentrated suspension being returned to the final stage and the spent liquor being discharged. Product crystals are taken from the first stage of the series.

Abstract: A reversible liquid/solid phase change composition comprising hydrated Mg(NO.sub.3).sub.2 /MgCl.sub.2, and one or more of Sr(OH).sub.2, Ca(OH).sub.2, CaO or BaO, added to the composition in an effective amount to suppress supercooling of the Mg(NO.sub.3).sub.2 /MgCl.sub.2 liquid phase.

Abstract: Boric acid is recovered from a water phase separated after hydrolyzing the reaction mixture obtained by oxidizing cyclohexane in the presence of a catalyst of boric acid. The method comprises(a) a concentration-crystallization step of concentrating the water phase by heating it and crystallizing boric acid;(b) a concentrating step of separating crystals of boric acid from the slurry obtained by the step (a) and then controlling the water content of the mother liquor to 20 to 50 wt. %;(c) a cooling-crystallization step of cooling the concentrated solution obtained by the step (b) under a reduced pressure to crystallize boric acid; and(d) a boric acid recycling step of separating crystals of boric acid separated from the slurry obtained by the step (c) and then, recycling the boric acid to the step (a).

Abstract: The invention is method and apparatus for removing dissolved solids from water by creating a condition of super-saturation of the solids material within a confined water circuit, propagating the formation of solids by a process of crystal nucleation and crystal growth and separating the crystallized solids. The invention also involves the apparatus for carrying out the process including a continuous process circuit for circulating a super-saturated liquor, which circuit comprises a source of heat energy for propelling the process and a cooling tower to provide evaporation and super-saturation, and further including a separator to remove crystallized solids from the liquor.

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: Dislocation and etch channel-free quartz resonator blanks are made from a cultured quartz stone by visualizing the dislocation-free areas of the cultured quartz stone by X-ray topography, cutting seed plates for the next generation of crystal growth from the dislocation-free areas of the cultured quartz stone, growing dislocation free quartz from said seed plates using conventional growth techniques, and cutting dislocation-free quartz resonator blanks from said dislocation-free quartz.