Abstract: Device and process for crystallizing a component, e.g.

Abstract: A process for purifying a sulfuric acid solution such as by cooling a sulfuric acid solution to at or near its freezing point to form a slurry of a solid phase and a liquid phase. The slurry has an acid-rich region and an acid-poor region. The acid-rich region is separated from the acid-poor region on the basis of density.

Abstract: The specification discloses an apparatus and method for treating a slurry containing sodium sesquisulfate to recover sulfate and acid constituents therefrom. The apparatus includes a treatment vessel having a separation wall delineating a clarifying zone and a mixing zone. Slurry containing sesquisulfate crystals is introduced into the mixing zone along with water and the material is mixed to promote dissolution of the crystals and formation of sodium sulfate solids. Sodium sulfate solids are collected in a lower portion of the treatment vessel and conveyed out of the vessel, and liquid from the clarifying zone is conducted from an upper end of the treatment vessel to a conventional liquid processing unit. Treatment of a sesquisulfate-containing slurry in accordance with the invention provides sodium sulfate containing little or no sesquisulfate crystals thereby reducing the need for vacuum filtration or other expensive separation techniques to recover sulfuric acid and sodium sulfate solids from the slurry.

Abstract: A method which can control crystallization of a biopolymer such as protein is provided. A silicon crystal (15) whose valence electrons are controlled to be capable of controlling the concentration of holes or electrons of the surface part in response to the environment of a mother liquor (14) containing the biopolymer such as protein is brought into contact with a buffer solution (12), for getting a crystal of the biopolymer deposited on the surface of the silicon crystal (15). Crystallization is controlled by an electrical state which is generated by the controlled valence electrons on the surface of the silicon crystal (15).

Abstract: Processes and apparatuses are provided for continuously harvesting particles from organic solution-laden near-critical and supercritical fluids. Broadly, the processes and apparatuses utilize a filter or separator comprising a thin membrane supported on a sintered stainless steel tube. A feed stream comprising the desired particles, a supercritical antisolvent for the particles (preferably CO.sub.2), and a solvent for the particles, is contacted with the membrane layer of the filter under supercritical conditions for the mixture of antisolvent and solvent. The preferred antisolvents are substantially miscible with the solvent and have a critical temperature of less than 160.degree. C. The desired particles are retained by the filter while the solvent and most of the antisolvent pass through the filter, resulting in separation of the particles from the solvent.

Abstract: The invention relates to a process for the preparation of crystalline sodium silicates having a sheet structure and high .delta. phase content from water glass, which has been prepared hydrothermally, by dehydration of the water glass and subsequent crystallization at elevated temperature, which comprises treating the water glass at temperatures of from 50 to 140.degree. C. prior to dehydration.

Abstract: A system and method for forming spherical semiconductor crystals is disclosed. The system includes a receiver tube 18 for receiving semiconductor granules 104. The granules are then directed to a chamber 14 defined within an enclosure 20. The chamber maintains a heated, inert atmosphere with which to melt the semiconductor granules into a molten mass. A nozzle, 40, creates droplets from the molten mass, which then drop through a long drop tube 16. As the droplets move through the drop tube, they form spherical shaped semiconductor crystals 112. The drop tube is heated and the spherical shaped semiconductor crystals may be single crystals. An inductively coupled plasma torch positioned between the nozzle and the drop tube melts the droplets, but leaving a seed in-situ. The seed can thereby facilitate crystallization.

Abstract: The process for producing crystallisation products with an average particle diameter of <1 .mu.m is based on the atomisation of a solution and the simultaneous evaporation of the solvent. The atomised solution A crystallises in a gas atmosphere, in which it is simultaneously contacted with a cloud of drops 4 of a surfactant-containing liquid B, thus forming an aerosol mixture A, B which is then deposited in the form of a colloidal crystal suspension in which the surfactant-containing liquid B forms the continuous phase. The cloud of drops 4 of the surfactant-containing liquid can also be produced by atomisation.

Abstract: Process for crystallizing fatty substances for their subsequent fractionation especially by pressure filtering, consisting in particular in melting the fatty substances, dividing the molten mass into beads, feeding these beads into a pre-refrigerated aqueous solution, adjusting the concentration of the fatty substance relative to the aqueous solution, adjusting the feed rate of said beads, adjusting the temperature of the beads/solution mixture, maintaining said mixture temperature until the crystallization of each bead has completely stabilized, subsequently transferring the beads/solution mixture to the filtration location, separating the fatty substance beads under a low pressure from the aqueous solution, and finally extracting from said fatty substance beads, under high pressure, the liquid portion of the fatty substance, and apparatus for applying this process.

Abstract: The invention provides a method for forming particles of a substance, by co-introducing into a particle formation vessel, in which the temperature and pressure are controlled, of a supercritical fluid; a solution or suspension of the substance in a first vehicle; and a second vehicle which is both substantially miscible with the first vehicle and substantially soluble in the supercritical fluid, in such a way that dispersion of the solution or suspension and the second vehicle, and extraction of the vehicles, occur substantially simultaneously and substantially immediately on introduction of the fluids into the vessel, by the action of the supercritical fluid.

Abstract: In a novel process for the production of particles or powders, a substance or mixture of substances to be treated is provided in a pressure vessel. A highly compressible fluid is dissolved under pressure in the substance or mixture of substances provided until a solution containing 5% to 90% by weight of said highly compressible fluid has formed. The melting point of said highly compressible fluid is at least around 40 K lower than the melting point of the substance or mixture of substances to be treated.

Abstract: The invention relates to a process for the preparation of crystalline sodium silicates having a sheet structure and high .delta. phase content from water glass, which has been prepared predominantly hydrothermally, by dehydration of the water glass and subsequent crystallization at elevated temperature, wherein the water glass is a mixture of water glass prepared hydrothermally and tank furnace water glass, and also to its use.

Abstract: For the purpose of separating a substance from a liquid mixture by crystallization, the inner walls of pipes in a crystallizer (S-1, S-2, S-3) are cooled by evaporating a liquid medium, the pressure of the gaseous phase of the medium being controlled in accordance with the temperature required for crystallization. In these conditions a layer of crystals forms on the outer walls of the pipes and can later be melted. The previously-formed crystal layer is melted in one crystallizer simultaneously with crystallization in another crystallizer. This is done by introducing gaseous medium which is produced in a crystallizer during the said evaporation. In addition, heat energy can be supplied to the crystallizer where melting occurs, in order to evaporate liquid medium there so that melting is accelerated. The two simultaneously operating crystallizers operate respectively as an evaporator and as a condenser in a refrigerating unit (11), thus saving considerable energy compared with known crystallization methods.

Abstract: A salt making method comprising putting a crude salt-water mixture (5) comprising crude salt or rock salt and bittern in a vessel (1), blowing the air from a pipe (7) into the mixture (5) with a pump (9), crystallizing the component salt out of the mixture (5), and precipitating the salt as a common salt (S) at the bottom of the vessel (1). The remainder of the mixture (5) is discharged through a filter (13) into a tank (17), where it is stored as a concentrated brine (15), which is then discharged through a filter layer (16) and a drain (18), and crude salt is dissolved therein to recycle as a crude salt-water mixture. The concentrated brine (15) may be used after being mixed with the extracts of aloe, mozuku (Nemacystis decipiens), rice bran, etc. The air may be blown into the mixture (5) under heating.

Abstract: A description is given of a process for producing weakly agglomerated, densified and/or crystallized nanosize particles which is characterized in that either(a) a suspension containing amorphous or partially crystalline nanosize particles is produced in a conventional manner from precursors for the nanosize particles, where the nanosize particles are produced in a solvent which has no solvent capability, or only a low solvent capability, for the particles and in the presence of at least one surface-blocking substance, or(b) an already formed powder comprising amorphous or partially crystalline nanosize particles is suspended in the solvent specified under (a) in the presence of the surface-blocking substance or substances specified under (a), or(c) a sol containing amorphous or partially crystalline nanosize particles is suspended in the solvent specified under (a) in the presence of the surface-blocking substance or substances specified under (a); andthe suspension thus produced is subjected to conditions wh

Abstract: Continuous process for the manufacture of solid particles of alkali metal persalts by reaction of an aqueous hydrogen peroxide solution with an aqueous solution of an alkali metal salt and crystallization of the persalt formed in a crystallizer-classifier comprising a stirred formation and growth region for the persalt crystals, a nonstirred clarifying region for the solution and a classification region for the particles obtained by elutriation in a liquid stream withdrawn in the clarifying region.Plant for manufacturing the said particles.

Abstract: An improvement is proposed in the so-called urea method for the preparation of fine particles of yttrium oxide, according to which, while an aqueous reaction mixture containing a water-soluble yttrium salt, e.g., nitrate, and urea dissolved therein in specified concentrations is heated at 90.degree. to 100.degree. C. to effect precipitation of yttrium carbonate hydroxide particles followed by calcination of the carbonate hydroxide in air into yttrium oxide, the aqueous reaction mixture is diluted with addition of a specified volume of preheated water within a critical period between incipient appearance of turbidity in the reaction mixture by the precipitation of the carbonate hydroxide and a moment 30 minutes thereafter. In this way, the yttrium oxide particles obtained have a globular particle configuration with a very small average particle diameter D.sub.50 in the range from 0.1 to 0.3 .mu.m and are suitable for use in various fine applications.

Abstract: A method for providing aerogels, and aerogels produced according to the method, is described. As one aspect, antiperspirant compounds that are in aerogel form, and antiperspirant and deodorant compositions including such salts, are described. The method involves contacting a solution containing material to be processed with a species selected to precipitate the material and selected so as to be miscible with the solvent system of the solution. After the material is precipitated, the material may be washed with the precipitating species until it is substantially free of solvent system. Then, the precipitating species containing the material precipitate is taken above its critical point, and the supercritical fluid is exhausted above its critical temperature. Alternately, a separate isolating species is introduced to displace the precipitating species, or the precipitating species/solvent system mixture. The isolating species then is taken above its critical point, and exhausted above its critical temperature.

Abstract: A process for separating a liquid eutectic mixture by crystallization of one eutectic forming substance of the mixture on a cold surface to which seed crystals of the eutectic forming substance have been applied in the form of a seed crystal layer, and subsequent removal of the eutectic forming substance in liquid form after heating of the surface.

Abstract: After being subjected to a melt crystallization operation, a crystal-containing melt is formed into particles of the same size and shape and then conducted in counter-flow relationship to washing liquid in a washing column. The crystal-containing melt can be formed into particles by a device which deposits the crystal-containing melt as identically sized drops onto a cooling belt. The particles can be completely hardened or only partially hardened when entering the washing column.

Abstract: An apparatus for the continuous crystallization of polyester material is described, which apparatus can likewise be used for the drying of granules. The apparatus operates to improve the residence behavior of the material and the process. This is achieved by a circular apparatus having a gas inlet and gas outlet and product entry and product outlet, The product entry and product outlet are arranged concentrically and parallel to the axis of the apparatus. A product outlet device is arranged so that it is axially displaceable.

Abstract: In a process for separating substances from a liquid mixture by crystallization in a crystallizer, a two-phase seed layer in the form of a melt or solution of the mixture to be separated, with crystals suspended therein, is applied, prior to the crystallization, to those surfaces of the crystallizer from which crystals grow during the crystallization.

Abstract: A method is described for preparing a concentrated dispersion of a photographically useful compound ready-for-use in coating solutions of hydrophilic colloid layers of a silver halide photographic material, wherein said compound has at least one ionisable acid site on its molecule, the said method comprising the steps of deprotonising and solubilising the said compound in alkaline medium; microprecipitating the said compound and milling the microprecipitated compound obtained, coating the said dispersion of a photographically useful compound in non-light-sensitive and/or light-sensitive hydrophilic layers of a silver halide photographic material, wherein milling proceeds during and/or after the microprecipitating step.

Abstract: Crystallization of a melt is induced by causing the melt to flow downwardly in a gap which is defined by upwardly moving cooled walls so that crystallate adheres to the walls and is carried upwardly for recovery. The walls are formed by endless belts which are cooled by fluid sprayed from nozzles. The walls are adjustable so as to be parallel or upwardly divergent.

Abstract: A method for accelerating the solidification rate of low melting products is disclosed. The method of the invention comprises the atomization of a molten low-melting product within a fluid stream which greatly enhances the rate at which the low-melting product solidifies.

Abstract: Mineral salts, e.g., potassium chloride, are crystallized from aqueous solutions thereof in the presence of a crystal growth promoting amount of lecithin or lecithin containing compositions. Mineral salts include alkali metal and alkaline-earth metal chloride, sulfate, carbonate, phosphate and nitrate salts. The process is described as providing increased amounts of large crystals and a narrower and more uniform crystal size distribution.

Abstract: The crystalliser (70) has an inlet (77) for the crystal medium to be fractionated and an outlet (84) from which the mother liquor followed by the molten crystals can be withdrawn at the end of the crystallisation process. During the crystallisation process, a number of tubes (75) closed at the top can be supplied from above with a trickling film of liquid mixture. The tubes are internally supplied with a trickling film of a liquid heat exchange medium used for cooling. The liquid heat exchange medium is supplied via a riser (87), and a medium distributor (92) guides the flow of medium heat exchange under the distribution tray (81). The pressure of the evaporating coolant in the medium chamber (80), to which the inner space of the tubes also belongs, is controlled, thus controlling the temperature of the wall of the tubes where crystallisation takes place. In order to melt the crystals, gaseous heat exchange medium is introduced through a spigot (96) into the crystalliser under controlled pressure.

Abstract: A process is provided for preparing microprecipitated dispersions of filter dyes by preparing a concentrated slurry in aqueous medium of a filter dye having ionizable acid sites on the dye molecule, adding sufficient aqueous hydroxide to dissolve the filter dye, acidifying the solution with a stoichiometric amount of acidic protons to reprotonate up to 100% of the total ionizable acid sites on the dye molecule and provide a microprecipitated dispersion of the filter dye that is insoluble in aqueous media at pH values less than 3 but soluble in aqueous media at pH greater than 10.

Abstract: The present invention pertains to a crystalline hydrated layered sodium silicate/amorphous sodium silicate composite material with predetermined hardness ion sequestration properties achieved by control of the process for forming the material, and a process for making the material. The process for producing the crystalline hydrated layered sodium silicate/amorphous sodium silicate composite consists of producing a crystalline sodium disilicate by heating a sodium silicate at a specified time and temperature. The resulting material may include amorphous material, and the crystalline sodium disilicate can be either alpha-phase or delta-phase disilicate. This crystalline sodium disilicate is then hydrolyzed with up to 50.0 milliequivalents per gram of either H.sub.3 O.sup.+ ions or OH.sup.- ions. The resulting material can sequester Ca.sup.2+ ions, Mg.sup.2+ ions, or both, depending on the results desired, processing conditions, and starting materials used.

Abstract: Disclosed herein is a crystallization apparatus for use in the crystallization of L-.alpha.-aspartyl-L-phenylalanine methyl ester. The stirring blade of the crystallization apparatus is composed of a band plate member for sweeping the bottom of a vessel and rod- or band plate-members arranged thereon and extending substantially vertically and horizontally.

Abstract: There is disclosed a dual jet crystallizer apparatus comprising a crystallization or mixing chamber having opposed angularly disposed arms which removably receive jet nozzles. One end of the chamber is provided with means to discharge crystallized product therefrom while the other end is equipped with means to adjust the crystallization volume within the chamber. The angular arms are disposed within specified angular tolerances with respect to the longitudinal axis of the chamber. One of the jet nozzles is provided with means at one end to receive and deliver to the chamber compound to be crystallized while one end of the other jet nozzle is provided with means to receive and deliver to the chamber a crystallization agent for the compound. The opposite ends of each of the jet nozzles have means to removably secure them to the angular arms and the ends thus secured have a nozzle tip section formed therein defining an orefice having an elongated bore.

Abstract: A process and an apparatus for the continuous crystallization of plastic granules, particularly amorphous plastic granules, in which the granules are introduced into a container and form a granule bed, which is moved downwards by the action of gravity. A hot gas is passed as a primary gas in a countercurrent manner through the granule bed. The granules are kept moving by a stirrer. There is also a gas supply for a secondary gas, which introduces the secondary gas at high speed at several points distributed over the cross-section of the container into the upper area of the granule bed.

Abstract: A method and apparatus for forming semiconductor particles (42) for solar cells using an optical furnace (30). Uniform mass piles (26) of powered semiconductor feedstock are almost instantaneously optically fused to define high purity semiconductor particles without oxidation. The high intensity optical energy is directed and focused to the semiconductor feedstock piles (26) advanced by a conveyer medium (16) thereunder. The semiconductor feedstock piles (26) are at least partially melted and fused to form a single semiconductor particle (42) which can be later separated from a refractory layer (18) by a separator (50), preferably comprised of silica. The apparatus (10) and process is automated, providing a high throughput to produce uniform mass, high quality spheres for realizing high efficiency solar cells. The apparatus is energy efficient, whereby process parameters can be easily and quickly established.

Abstract: Methods and reaction systems are disclosed that are adapted for forming crystallites having novel crystal habits and/or morphologies compared to conventional crystallites of the same chemical composition. The methods and reaction systems involve chemical reactions between at least two reactant compounds occurring in a liquid (or gel) that form insoluble crystallite products. At least one of the reactants is rendered soluble in a solvent in which the reactant is not normally soluble by adding an agent that forms soluble molecular complexes of the agent and the reactant. The complexing agent not only facilitates dissolution of the reactant in the solvent but also plays a role in how the faces of crystals comprising the crystallite product are enlarged during formation of the product. Products having such altered crystallite structure have a number of possible uses.

Abstract: This invention relates to a single crystallization process for purification of dimethyl terephtalate (DMT) by film crystallization, including pumping the raw DMT into a film crystallizer and reducing its temperature to form DMT crystalline on the walls of the crystallizing pipes in the crystallizer, and then heating the crystallizing pipes and collecting the melt at 140.degree.-145.degree. C. The product DMT is thus obtained.

Abstract: A porous prilled product, particularly ammonium nitrate, and its method of preparation, which includes encapsulated microspheres, particularly polymer microballoons, which serve to reduce the density of the product.The invention also extends to an explosives composition particularly ANFO and heavy ANFO, including such ammonium nitrate of reduced density.

Abstract: A multistage process for the separation and purification of a desired crystalline material by repeated dissolution and recrystallization, wherein crystals and solvent move countercurrent to one another through the stages. A fluid temperature gradient is maintained within each recrystallization unit to make use of convection to facilitate or accelerate concurrent dissolution and recrystallization within a single vessel. Solid recrystallized material is moved from one unit to the next unit. An automated apparatus and a manually operated apparatus for carrying out the process are also described.

Abstract: The problems in crystallization of .alpha.-L-aspartyl-L-phenylalanine methyl ester, namely, problems in crystal slurry properties in solid-liquid separation, scaling at heat transfer surfaces, and the like, are solved by a method for crystallization of .alpha.-L-aspartyl-L-phenylalanine methyl ester which comprises cooling a solution of .alpha.-L-aspartyl-L-phenylalanine methyl ester by indirect heat exchange with a coolant while stirring, wherein the solution is cooled by circulating a coolant while continuously adding an aqueous solution of .alpha.-L-aspartyl-L-phenylalanine methyl ester dropwise to a crystallizing solution of .alpha.-L-aspartyl-L-phenylalanine methyl ester having a temperature difference of not greater than 20.degree. C. from the coolant, thereby to keep a temperature difference of not greater than 20.degree. C. between the coolant and the crystallizing solution.

Abstract: Adiabatic self-evaporation cooling of a refrigerant is performed in a crystallizer for a treated organic matter which contains the refrigerant and is fed into the crystallizer. Crystals produced by the adiabatic self-evaporation cooling are withdrawn from the crystallize. An evaporated vapor is introduced from the crystallizer into an absorber so as to be contacted with a concentrated solution transformed from a generator for condensation in the absorber. A condensate is introduced from the absorber into the generator, the refrigerant is evaporated in the generator, an evaporated vapor is introduced from the generator to the condenser, the evaporated vapor is condensed in the condenser, a condensate is supplied from the condenser to the crystallizer and the concentrated solution is circulated between the absorber and the generator by returning the concentrated solution, in which the concentration of an absorbent is increased by the generator to the absorber.

Abstract: A silicon single crystal for use as semiconductor is grown by supplying, to a seed rod of single-crystal silicon, hydrochloride gas and silicon formed by admixing at least one chlorosilane gas selected from the group consisting of dichlorosilane, trichlorosilane and tetrachlorosilane with hydrogen gas at a high temperature to grow single-crystal silicon on the seed rod while etching the growing single-crystal silicon with the hydrochloride gas. The silicon single crystal is irradiated with laser rays so that the energy of the laser rays on the irradiated surface of the crystal ranges from 3100 to 3358 mW/cm.sup.2 and then spectra emitted by the crystal are optoelectrically determined to quantify the ultratrace elements present in the silicon single crystal. Moreover, the amounts of these ultratrace elements are reduced to those of ultratrace elements present in the chlorosilane gas.

Abstract: Crystallization of adipic acid using low intensity ultrasonic agitation during crystallization results in purer product that is more readily handled. Apparatus for carrying out the process is also disclosed.

Abstract: A method and apparatus are provided for superpurifying crystallizable substances to a purity level of 99.999%. Included is a closed multistage system which maintains controlled transfers of material between a plurality of stages. The method and apparatus avoid the need to transfer solid crystals from one stage to another and effect efficient and very effective separation of purified crystals from their mother liquor.

Abstract: A method for the production of spherically shaped granules of low melting point, corrosive, subliming substances which comprises melting the substance and discharging the melt through a perforated bottom receiver and into a prilling tower in the form of a plurality of streams having diameters of 0.5 to 4.0 mm which form droplets as they fall through the tower. The prilling tower has 10 to 20 mm diameter lateral perforations through each of which a mixture of air and an atomized liquid, with a lower boiling point than the melting point of the subliming substance, is introduced to form a mist. The mist is cooled below the atmospheric temperature and transformed into a low temperature fog which minimizes sublimination. The droplets are solidified as they pass through the fog during their fall through the tower and form granules having a diameter of 0.5 to 4.0 mm which are received on a curved screen to prevent breakage.

Abstract: In a process for recovering an alkali metal azide from a waste gas generating material containing the alkali metal azide and a metal oxide reactable with the azide, the gas generating material is mixed with a solvent for the alkali metal azide. This produces a slurry comprising (i) a solution comprising the solvent and the alkali metal azide, and (ii) the metal oxide. The slurry is separated into a liquid stream comprising primarily the solution and a sludge stream comprising primarily the metal oxide. The liquid stream is filtered in a filter to produce a filtrate which is substantially free of metal oxide and is then concentrated by evaporation of the solvent to produce crystals of the alkali metal azide. The separation may be carried out by a filter or centrifuge to produce a filter or centrifuge cake. The sludge obtained from the slurry is reslurried to recover additional azide, and the resulting slurry is again separated into a sludge and a liquid stream by a filter or centrifuge.

Abstract: An evaporator control method for a salt manufacturing plant includes the steps of: measuring the speed of sound of in a raw solution of salt which additionally includes magnesium chloride and calcium chloride accommodated in an evaporator; calculating the combined concentration of magnesium chloride and calcium chloride according to the speed of sound based on a calibration curve; and controlling a condition of the raw solution in the evaporator according to the combined concentration of magnesium chloride and calcium chloride.

Abstract: The problems in crystallization of .alpha.-L-aspartyl-L-phenylalanine methyl ester, namely, problems in crystal slurry properties in solid-liquid separation, scaling at heat transfer surfaces, and the like, are solved by a method for crystallization of .alpha.-L-aspartyl-L-phenylalanine methyl ester which comprises cooling a solution of .alpha.-L-aspartyl-L-phenylalanine methyl ester by indirect heat exchange with a coolant while stirring, wherein the solution is cooled by circulating a coolant while continuously adding an aqueous solution of .alpha.-L-aspartyl-L-phenylalanine methyl ester dropwise to a crystallizing solution of .alpha.-L-aspartyl-L-phenylalanine methyl ester having a temperature difference of not greater than 20.degree. C. from the coolant, thereby to keep a temperature difference of not greater than 20.degree. C. between the coolant and the crystallizing solution.

Abstract: A system for crystallization of polymers involving the use of a stationary housing with a rotor mounted for rotation within the housing. The rotor supports a plurality of spaced apart hollow discs and heated fluid is delivered to the interior of the discs. The polymer material to be treated is fed into the housing for heat exchange contact with the exterior surfaces of the discs. The rotation of the discs in addition serves as the propelling force for the material along the length of the housing at which point the material is discharged. The speed of rotation of the rotor is controlled to influence agitation and conveying of material in the housing to thereby control the crystallization reaction. A holdup mechanism which operates independently of the speed control is located adjacent the discharge location to contribute to the fixing of the residence time.

Abstract: Adiabatic self-evaporation cooling of a refrigerant is performed in a crystallizer for a treated organic matter which contains the refrigerant and is fed into the crystallizer. Crystals produced by the adiabatic self-evaporation cooling are withdrawn from the crystallize. An evaporated vapor is introduced from the crystallizer into an absorber so as to be contacted with a concentrated solution transformed from a generator for condensation in the absorber. A condensate is introduced from the absorber into the generator, the refrigerant is evaporated in the generator, an evaporated vapor is introduced from the generator to the condenser, the evaporated vapor is condensed in the condenser, a condensate is supplied from the condenser to the crystallizer and the concentrated solution is circulated between the absorber and the generator by returning the concentrated solution, in which the concentration of an absorbent is increased by the generator to the absorber.

Abstract: Process for isolating dimethyl 4,4'-biphenyldicarboxylate from residues of DMT production, which includes first distilling the residues at a pressure of at most 7 mbar at a boiler temperature from 200.degree. to 350.degree. C., subsequently treating the distillate which distills over in the range from 230.degree. to 270.degree. C. at a pressure of, for example, 0.2 mbar for from 10 to 60 minutes with 0.7 to 10 times the amount of an organic solvent at a temperature from 70.degree. to 180.degree. C., if required, separating the clear solution from undissolved components, cooling the removed clear solution to a temperature from 45.degree. to 65.degree. C. and allowing it to crystallize at this temperature, resulting in a suspension of dimethyl 4,4'-biphenyldicarboxylate crystals from which the crystals are isolated by washing one or more times with the same or a different solvent and by drying.

Abstract: High purity, crystalline adduct of bisphenol A and phenol is produced multi-stage crystallization of a phenolic slurry of bisphenol A with a crystal separation and washing step being interposed between each of the two stages. Each of the crystallization stage includes a series of crystallization towers operated at decreasing temperatures. The crystallization of the slurry is performed by continuously discharging a portion of the slurry from each of the crystallization towers, introducing the discharged slurry into one or more coolers and then recycling the cooled slurry to the tower. Another portion of the slurry in each crystallization slurry is continuously discharged, heated for dissolving fine crystals of the adduct and then recycled to the crystallization tower so that large crystals are grown in each of the crystallization steps. An apparatus having a plurality of coolers and suitable for effecting the above crystallization is also disclosed.