Abstract:
The invention relates to an installation comprising a combustion chamber (15) provided with means (53) which are used to introduce the mineral load and are connected to a pre-heater (27), combustion means (55) for maintaining the chamber (15) at a temperature of between 700° C. and 900° C., means (57) for introducing a treatment gas having a controlled carbon dioxide content in order to oppose the dissociation of the carbonate in the chamber (15), and means (61) for removing the calcinated mineral load guided into a cooler (31). The chamber (15) comprises means (51) for forming a fluidised bed. The means (57) for introducing treatment gases are supplied at least partially by a line (91) or deriving part of the combustion flue gases of the chamber (15) emitted by means for discharging (21) said flue gases into the atmosphere. The invention can be used for the production of a cement-type hydraulic binder.
Abstract:
A mixture contains one or more vinyl-containing compounds as component (A) and, as a further component, a stabilizer (B) which contains one or more readily volatile nitroxyl compounds as component (b1), one or more sparingly volatile nitroxyl compounds as component (b2), if required one or more aromatic nitro compounds as component (b3) and, if required, one or more iron compounds as component (b4). Stabilizers (B) contain the components (b1) and (b2), (b1) and (b2) and (b3), (b1) and (b2) and (b4), and (b1), (b2), (b3) and (b4), and the premature polymerization of vinyl-containing compounds during their purification or distillation is inhibited by a process in which a stabilizer (B) is added or the components of stabilizer (B) are added as individual substances or in at least two groups of the components.
Abstract:
In a process for the continuous distillation of thermolabile monomers under reduced pressure in the presence of formamide in a column,the thermolabile monomers are continuously fed in liquid form, separately from formamide, into the lower part of the column up to the middle of the column,Formamide is vaporized with a vaporizer at the bottom of the column and, together with constituents having higher boiling points than the thermolabile monomers, is discharged from the bottom of the column and replaced by addition of fresh formamide,the thermolabile monomers are taken off at a side offtake in the upper third of the column, with the distillation being controlled such that the monomers contain less than 5% by weight of formamide, anda product stream containing constituents which have a lower boiling point than the thermolabile monomers is taken off at the top of the column.
Abstract:
7-Chloroquinoline-8-carboxylic acids of the formula (I) ##STR1## where R is hydrogen, chlorine or methyl, are prepared by direct oxidation of the corresponding 8-methylqunoline compound with nitric acid or nitrogen oxide in the presence of sulfuric acid and a heavy metal catalyst.
Abstract:
Process for the preparation of sulfuric acid monoesters of aminoalkanols by reacting sulfuric acid with aminoalkanols and removing the water forming in the reaction from the reaction mixture, sulfuric acid and at least one aminoalkanol being mixed and the hot reaction mixture forming being passed with turbulent flow into a container and being quenched therein with a fluid.
Abstract:
The invention relates to a process for producing paper, board and cardboard of high dry strength by separately adding a polymer comprising vinylamine units and a polymeric anionic compound to a paper pulp, dewatering the pulp and drying the paper products, which comprises using as polymeric anionic compound at least one copolymer obtainable by copolymerizing (a) at least one N-vinylcarboxamide of the formula in which R1 and R2 are H or C1- to C6 alkyl, (b) at least one monoethylenically unsaturated monomer comprising acid groups, and/or the alkali metal, alkaline earth metal or ammonium salts thereof, and if appropriate (c) other monoethylenically unsaturated monomers, and if appropriate (d) compounds having at least two ethylenically unsaturated double bonds in their molecule.
Abstract:
An installation comprising a combustion chamber having a device for introducing the mineral load and that is connected to a preheater, a combustion device to maintain the chamber at a temperature between 700° C. and 900° C., a treatment gas introducing device, the gas having a controlled carbon dioxide content in order to oppose the dissociation of the carbonate in the chamber and a device for removing the calcined mineral load guided into a cooler. The chamber also forms a fluidized bed. The treatment gas introducing device is supplied, at least partially, by a bypass duct, with some of the flue gases from the chamber coming from a device for discharging these gases into the atmosphere. This may be used in the production of a cement-type hydraulic binder.
Abstract:
A process for the continuous distillation of thermolabile monomers under reduced pressure in a column includesfeeding the thermolabile monomers in vapor or liquid form to the column,introducing an inert distillation aid which forms a heteroazeotrope with the thermolabile monomers into the vaporizer at the bottom of the column, but separately from the monomer feed, and vaporizing into there or feeding an emulsion of thermolabile monomers and an inert distillation aid into the vaporizer or into the column,condensing the azeotrope at the top of the column and separating it in a phase separator, taking off the thermolabile monomers and returning the distillation aid to the column or, if desired, working it up by distillation andtaking off components having a higher boiling point than the thermolabile monomers from the bottom of the column.
Abstract:
1-Nitroanthraquinone-2-carboxylic acids of the general formula I ##STR1## where X is hydrogen, chlorine or bromine, are prepared by oxidizing a 1-nitro-2-methylanthraquinone of the general formula II ##STR2## with nitric acid in an organic reaction medium.
Abstract:
Aqueous slurries of finely divided fillers which are at least partly coated with polymers and which are obtainable by treating aqueous slurries of finely divided fillers with at least one water-soluble amphoteric copolymer whose structures are identified in the specification are used as an additive to the paper stock in the production of filler-containing paper, filler-containing cardboard or filler-containing board by draining of the paper stock.