Abstract: The invention relates to a method for purifying wastewaters of melamine systems. The method is characterized in that triazine-containing wastewater is subjected to a thermal pretreatment stage, whereupon the vapors are condensed from the gas phase of the thermal pretreatment stage, and the liquid phase of the thermal pretreatment stage is subjected to a thermal hydrolysis stage while NH3 is isolated from the obtained liquid phase containing H2O, CO2, and NH3. The inventive method makes it possible to compensate varying wastewater qualities, thus allowing the melamine system and wastewater station to be operated in a constant and safe fashion. Furthermore, the strain on the subsequent thermal hydrolysis stage is relieved with the aid of the thermal pretreatment stage of the inventive method.

Abstract: The invention relates to melamine-formaldehyde condensates with thermoplastic properties that can be produced from formaldehyde and melamine derivatives, wherein at least one of the melamine derivatives organic radicals R have been used to substitute at least four of the total of six hydrogen atoms of the three melamine amino groups, and wherein the organic radicals R are mutually identical or different. The invention also relates to a process for production of the melamine-formaldehyde condensates, use thereof, and an analytical method for determining the constitution of the melamine-formaldehyde condensates.

Abstract: The invention relates to a method for producing pure melamine by preparing a melamine melt, which is obtained in a high pressure process and from which the reaction gases are removed. Said method is characterized in that the melamine melt is quenched by water with a purity in excess of 95 wt. %, that NH3 and CO2 are subsequently removed from the obtained melamine solution and that alkali is added to said melamine solution and the mixture is then left to rest, whereby pure melamine is obtained by crystallization. Thus a melamine can be obtained with the same quality as that produced in known comparative methods, using smaller quantities of alkali.

Abstract: The invention relates to a method for treating triazine-containing water of a melamine plant. The method is characterized in that the water containing ionic and non-ionic triazines in a dissolved form is fed to at least one membrane filtration unit, the water is separated into an ionic triazine-rich fraction and a non-ionic triazine-rich fraction in the membrane filtration unit, whereupon the ionic triazine-rich fraction is discharged and the non-ionic triazine-rich fraction is redirected into the melamine plant. The inventive method allows a great portion of the melamine contained in the triazine-containing water to be redirected into the process while the yield is increased along the entire melamine process. Furthermore, the need for fresh water in the wet part of the melamine plant is decreased. The disclosed method can be carried out continuously and in liquid phase.

Abstract: The invention relates to a device for thermally purifying waste water, comprising a tank through which waste water can flow. The inventive device is characterized by having at least one flow guiding means for guiding the waste water inside the tank in an essentially meandering manner, and by having at least one heating means inside the tank for regulating a predetermined temperature.

Abstract: The invention relates to melamine resin, wherein it is, in essence, linearly synthesized and is dependent upon the viscosity of the rate of shear. The invention also relates to a method for producing the melamine resin and to the use thereof.

Abstract: A melamine-formaldehyde resin solution having a formaldehyde/melamine ratio smaller than or equal to 1.5, at which it possesses a water compatibility ranging from 0.15 to 4.0 at 20° C., and a stability of at least 5 hours at a F/M ratio of 1.0, a stability of at least 6 hours at a F/M ratio of 1.1, a stability of at least 13 hours at a F/M ratio of 1.2, a stability of at least 24 hours at a F/M ratio of 1.3, a stability of at least 50 hours at a F/M ratio of 1.4, and a stability of at least 200 hours at a F/M ratio of 1.5, the stability of the resin solution being linearly dependent, within the range boundaries 1.0<F/M<1.1, 1.1<F/M<1.2, 1.2<F/M<1.3, 1.3<F/M<1.4, 1.4<F/M<1.5, upon the stabilities of the corresponding F/M range boundaries.

Abstract: The invention relates to a device for thermally purifying waste water, comprising a tank through which waste water can flow. The inventive device is characterized by having at least one flow guiding means for guiding the waste water inside the tank in an essentially meandering manner, and by having at least one heating means inside the tank for regulating a predetermined temperature.

Abstract: The invention relates to a method for treating triazine-containing water of a melamine plant. The method is characterized in that the water containing ionic and non-ionic triazines in a dissolved form is fed to at least one membrane filtration unit, the water is separated into an ionic triazine-rich fraction and a non-ionic triazine-rich fraction in the membrane filtration unit, whereupon the ionic triazine-rich fraction is discharged and the non-ionic triazine-rich fraction is redirected into the melamine plant. The inventive method allows a great portion of the melamine contained in the triazine-containing water to be redirected into the process while the yield is increased along the entire melamine process. Furthermore, the need for fresh water in the wet part of the melamine plant is decreased. The disclosed method can be carried out continuously and in liquid phase.

Abstract: The invention relates to solid particles and to a method for the production thereof from a flowable starting material and a solid part, wherein the flowable starting material is split into droplets which are introduced along a trajectory into a solidification liquid in which they are solidified in the form of the solid particles. The invention is characterized by the use of solidification liquid and, if the flowable starting material contains actinide oxide, the solidification liquid steadily flows, thereby making it possible to produce solid particles having a greater sphericity and a narrow particle sized distribution.

Abstract: The invention relates to a device for thermally purifying waste water, comprising a tank through which waste water can flow. The inventive device is characterized by having at least one flow guiding means for guiding the waste water inside the tank in an essentially meandering manner, and by having at least one heating means inside the tank for regulating a predetermined temperature.

Abstract: The invention relates to a flame-resistant amino resin system, in particular a melamine formaldehyde resin system, a melamine-urea formaldehyde resin system or a urea formaldehyde resin system, having: a) a modified amino resin matrix, the primary aminoplast condensation products being present at least partially in etherified form and the modified amino resin being obtained from an amino resin melt that is essentially devoid of solvent; and b) at least one compound, which acts as the flame-resistant component, contains phosphorus and/or nitrogen and/or boron in chemically bonded form and which is present in the amino resin matrix in encapsulated form. This permits the development of an amino resin system that can be thermoplastically treated, has excellent flame-resistant properties and in addition exhibits optimal curing, processing and surface characteristics.

Abstract: The invention relates to a method and a device for producing melamine by means of the thermal conversion of urea. The invention is characterized in that: a) urea is reacted to form melamine at least partially under reaction conditions wherein an educt, an intermediate and/or an end product are present in a supercritical state; and b) the mixture consisting of at least one educt, an intermediate and/or an end product essentially forms a homogeneous phase and all educts, intermediates, and/or end products are in a complete solution. The single-phase reaction results in an especially efficient reaction.

Abstract: The invention relates to a high pressure method for producing pure melamine by pyrolyzing urea in a vertical synthesis reactor. The synthesis reactor has three stages above one another: a) in the first stage, the smaller portion of the total amount of urea is introduced into the central tube of a first tank reactor forming a first melamine-containing reaction medium; b) in the second stage, the first melamine-containing reaction medium and the larger portion of the total amount of urea is introduced into the central tube of a second tank reactor forming a second melamine-containing reaction medium; c) in the third stage, the second melamine-containing reaction medium is introduced into a vertical tubular flow reactor forming a raw melamine melt that is processed to obtain pure melamine.

Abstract: A two-stage process is provided for purifying off-gases from a high-pressure melamine plant. In the first stage, the off-gases are contacted with a recirculated urea melt containing melamine precursors and NH3. In the second stage, the off-gases are contacted with a fresh urea melt.

Abstract: The invention relates to a flame-retardant mixture for lignocellulose composites having from 60 to 90% by mass of particulate or fibrous lignocellulose materials and from 40 to 10% by mass of a flame retardant concentrate immobilized on or in the particulate or fibrous lignocellulose materials as carriers. The flame retardants are boric acids or the salts thereof. Also, melamine resins and optionally synergistic agents and further additives may be present. The preparation of the flame-retardant mixture can be effected by a liquid impregnation process, a melt impregnation process and a liquid impregnation/solids mixing process. In the form of flame-retardant semifinished products and molding materials, the lignocellulose composites have high resistance to insect infestation, fungal infestation and mold infestation and high resistance to washing out of the flame-retardant mixture and are preferably suitable for applications in outdoor use in the building and leisure sector.

Abstract: The invention relates to composite materials, comprising plastics and wood, with 55 to 90 mass % of wood in the form of sawdust, wood fibres, and/or wood chippings and 45 to 10 mass % of partly crosslinked melamine resin ethers or mixtures of partly crosslinked thermoplastics and crosslinked melamine resin ethers, whereby the plastics in the composite materials can be in the form of a foam. Said materials can be produced by homogenization of the components in the extruder, pre-impregnation of wood with melamine resins in the screw mixer and subsequent homogenization of the components in the extruder, or by a sinter method, each followed by a subsequent moulding to give the composite material. The composite materials are suitable for application in building and in sport and leisure applications.

Abstract: The invention relates to a high pressure method for producing pure melamine by pyrolyzing urea in a vertical synthesis reactor. The synthesis reactor has three stages above one another: a) in the first stage, the smaller portion of the total amount of urea is introduced into the central tube of a first tank reactor forming a first melamine-containing reaction medium; b) in the second stage, the first melamine-containing reaction medium and the larger portion of the total amount of urea is introduced into the central tube of a second tank reactor forming a second melamine-containing reaction medium; c) in the third stage, the second melamine-containing reaction medium is introduced into a vertical tubular flow reactor forming a raw melamine melt that is processed to obtain pure melamine.

Abstract: The invention relates to a method and a device for producing melamine by means of the thermal conversion of urea. The invention is characterized in that: a) urea is reacted to form melamine at least partially under reaction conditions wherein an educt, an intermediate and/or an end product are present in a supercritical state; and b) the mixture consisting of at least one educt, an intermediate and/or an end product essentially forms a homogeneous phase and all educts, intermediates, and/or end products are in a complete solution. The single-phase reaction results in an especially efficient reaction.

Abstract: The invention relates to a method for producing melem-free melamine by means of aqueous processing of a melted mass of melamine which is obtained using a high-pressure method. According to the inventive method, the melted mass of melamine is quenched by means of an aqueous solution containing alkalis, following the isolation of the off-gases, and is directly transferred into an aqueous alkaline melamine solution, out of which the melamine is then crystallized. The invention thus enables melamine to be obtained, with a melam content of less than 1000 ppm and a melem content of less than 50 ppm. The invention also relates to a quenching agent.