Abstract: For the preparation of crystalline sodium silicates having a sheet structure and an SiO.sub.2 /Na.sub.2 O molar ratio of 1.9:1 to 3.5:1 from waterglass solutions having a solids content of 20 to 65% by weight, the waterglass solutions are first treated in a spray-drying zone. This gives a pulverulent amorphous sodium silicate having a maximum ignition loss of 20% by weight, while the waste gas leaving the spray-drying zone is at a temperature of at least 140.degree. C. Thereafter, the spray-dried sodium silicate is heated in an ignition zone containing an agitated solid bed at temperatures of 500.degree. to 800.degree. C. for 1 to 60 minutes in the presence of at least 10% by weight of recycled material. This recycled material was obtained by mechanical comminution of crystalline sodium silicate discharged from the ignition zone.

Abstract: To prepare crystalline sodium silicates having a layer structure and the formula Na.sub.2 Si.sub.x O.sub.2x+1, in which x is between 2 and 3, sand and soda are first fused in a molar ratio of SiO.sub.2 /Na.sub.2 O of 2 to 3.5 at temperature of 1200.degree. to 1400.degree. C. The water-glass obtained in pieces after the melt has cooled is ground to particle sizes of less than 2 mm before it is treated at temperatures of 600.degree. to 800.degree. C. for 10 to 120 minutes in an elongated reaction zone with mechanical circulation. Finally, the material leaving the reaction zone is ground to a particle fineness of less than 1 mm.

Abstract: For producing substantially water-insoluble, chain-type ammonium polyphosphate, equimolar quantities of diammonium phosphate and phosphorus pentoxide are reacted at temperatures from 170.degree. to 350.degree. C. in a zone, which effects continuous mixing, kneading and comminution, in the presence of a stream of ammonia gas. In this process, the water is separated from the ammonia gas which leaves the zone and contains water vapor, and the dried ammonia gas is caused to flow again through the zone.A plant for producing substantially water-insoluble, chain-type ammonium polyphosphate can comprise a reactor (1) into which an ammonia feed pipe (8) and pipes for feeding phosphorus pentoxide (6) and diammonium phosphate (7) lead and from which an ammonium polyphosphate discharge pipe (9) and an exit gas pipe (10) start. The exit gas pipe (10) leads into a condenser (13) which is flow-connected via a pump (14) to a heat exchanger (15).

Abstract: A process for inhibiting and destroying peroxides in dialkyl ethers having the general formula R.sub.1 OR.sub.2 in which R.sub.1 and R.sub.2 are alkyl groups having 1 to 6 carbon atoms, which comprises adding, as inhibitor, a quaternary alkyl iodide of the general formula[CH.sub.3 alk.sub.3 P]Ito the dialkyl ethers.

Abstract: A process for removing metallic corrosion products from carbonylation reactions which are carried out under anhydrous conditions and in which methyl acetate and/or methanol and/or dimethyl ether are reacted over a noble metal catalyst system which comprises a noble metal of group VIII of the periodic table of the elements, a co-catalyst, such as iodide or bromide, in particular methyl iodide, and a promoter, such as an organophosphonium or organoammonium salt, and if appropriate a lithium salt, to give acetic acid and/or acetic anhydride is described, the process comprisinga) bringing the reaction solution which is contaminated with metallic corrosion products and contains the catalyst system into contact with an ion exchanger;b) separating this reaction solution which has been brought into contact in this way from the ion exchanger;c) desorbing the promoter adsorbed on the ion exchanger before regeneration with acetic acid and/or acetic anhydride;d) combining the eluate obtained in step c) with the reaction

Abstract: Alkali metal phosphate solutions having a fluorine content of less than 20 ppm, based on P.sub.2 O.sub.5, are prepared by first digesting crude phosphate using sulfuric acid, and separating the calcium sulfate from the crude phosphoric acid. An alkali metal compound is then added to the crude phosphoric acid, and the precipitated solid is filtered off. The prepurified crude phosphoric acid is neutralized to a pH of at least 7, and the solid produced during this operation is separated off. The resultant alkali metal phosphate solutions having a P.sub.2 O.sub.5 content of from 10 to 30% by weight are adjusted to a pH of between 4.8 and 6.0 using phosphoric acid. The solutions are heated to from 60.degree. to 120.degree. C., and from 1 to 6% by weight, based on the weight of the solution, of an alkaline earth metal oxygen compound are added to the alkali metal phosphate solutions with stirring.

Abstract: The invention relates to a process for the isolation of vinyl acetate which involves not combining the bottom product of the recylced gas washings with the water-saturated vinyl acetate but rather introducing it to further multiple distillation columns from the gas mixture formed in the reaction of ethylene with acetic acid and oxygen over catalysts containing palladium or palladium compounds in the gas phase.

Abstract: Phosphoric acid substantially free from titanium is made from the organic extract obtained by subjecting crude phosphoric acid containing titanium to extractive purification with an organic solvent immiscible or only partially miscible with water. To this end, the organic extract is scrubbed in a scrubbing zone with a stage number of n>4 by introducing the crude extract into stage 1 and scrubbing it countercurrently with an aqueous alkaline solution in one of stages 2 to n-2 and with pure scrubbing water in stage n.

Abstract: Crude phosphoric acid is made by subjecting crude phosphate ore containing sulfide to processing treatment with a mineral acid in a closed system comprised of a processing reactor, a filtering zone and an off-gas scrubbing zone. To this end, a soluble compound of a metal forming difficultly soluble sulfides in the respective acid medium is added either(A) during the processing operation the phosphate ore is subjected to or(B) during the scrubbing operation the off-gas is subjected toand the resulting sulfide precipitate is filtered off in case (A) together with further matter precipitated during the processing operation and, in case (B) separated from the scrubbing liquid.

Abstract: Residue obtained upon the removal of heavy metal contaminants from crude phosphoric acid by means of a dialkyldithiophosphoric acid ester and adsorbent is worked up into ecologically reliable solid matter and into a heavy metal concentrate. The solid matter and heavy metal concentrate are separated from one another by successive mechanical and chemical treatment. The sequential order of these two operational steps can be inversed.

Abstract: Wet process phosphoric acid is freed from heavy metal ions, especially from ions of cadmium, copper, mercury, lead and arsenic and optionally also from organic compounds and sulfuric acid. To this end, the phosphoric acid is contacted with a diorganyldithiophosphoric acid ester and an adsorbent, if desired. Prior to or after said treatment with the ester, the phosphoric acid is admixed with a reductant. The adsorbent, if any is used alone or in combination with an alkaline earth metal compound soluble in phosphoric acid.

Abstract: The reactivity of phosphorus pentoxide is reduced and its flow behavior improved. To this end, phosphorus pentoxide in the form of its hexagonal modification is annealed over a period of 0.5 to 8 hours at temperatures of 200.degree. to 390.degree. C.

Abstract: Wet-process phosphoric acid is made by subjecting a phosphate ore to processing treatment with a mineral acid resulting in the formation of a processed suspension. The formation of silicofluorides is obviated by adding, either to the phosphate ore or the processed suspension, a quantity of an aluminum compound soluble in phosphoric acid sufficent for the processed suspension to present an aluminum concentration of 0.3 to 1.0 wgt %, based on P.sub.2 O.sub.5.

Abstract: An aqueous alkali phosphate solution is made. An organic phase is countercurrently mixed with an aqueous phase, the two phases being used in a volume ratio larger than 1:1 and formed aqueous alkali phosphate solution is separated from the remaining organic phase. The two phases are mixed and reacted in a reaction zone comprised of a mixing and separating zone. The organic phase is continuously dispersed in the aqueous phase. A volume excess of aqueous phase is maintained in the mixing zone and the two phases are used in an overall quantity sufficient to provide a volume ratio of organic to aqueous phase of 4:6 to 2:8.

Abstract: Phosphoric acid solutions are dearsenified by treating them with a sulfide and separating the resulting precipitate from the purified solution. The sulfide is at least one compound of the general formula P.sub.4 S.sub.x in which x stands for a number of 3 to 10.

Abstract: The disclosure relates to a process for making alkali metal phosphate solutions containing little fluorine from pre-purified alkali metal phosphate solutions obtained from crude phosphoric acid by extracting the acid with an organic solvent being immiscible or only partially miscible with water, scrubbing the crude extract with water or an alkali metal solution, re-extracting the phosphoric acid from the scrubbed extract with the use of an aqueous alkali metal solution while establishing an alkali metal/P-molar ratio equal to or larger than 1:1, and separating the resulting organic phase from the pre-purified alkali metal phosphate solution obtained.To this end, the disclosure provides:(a) for the pre-purified alkali metal phosphate solution to be stirred at 60.degree.-120.degree. C. into a compound of an alkaline earth metal Me.sup.2+ with a solubility in water at 20.degree. C. of more than 0.01 mol Me.sup.

Abstract: Wet-process phosphoric acid prepurified by liquid/liquid extraction with an organic solvent is decontaminated. To this end, the prepurified acid is first freed from residual extractant, then stripped with steam or hot gas, contacted with a dialkyldithiophosphoric acid ester and a fine particulate adsorbent, and liquid phase material is ultimately treated with steam and hydrogen peroxide.

Abstract: The disclosure relates to a process for defluorinating alkali metal phosphate solutions. To this end, the disclosure provides for an alkali metal phosphate solution neutralized to a pH-value of more than 6 and pre-purified to be stirred at 60.degree. to 120.degree. C. into an alkaline earth metal compound. Alkaline earth metal compounds with a solubility in water of less than 5 g/l are used in the form of particles of which more than 50% have a size of less than 8 .mu.m. After a reaction period of 0.5 to 4 hours, the precipitate obtained is separated from the purified alkali metal phosphate solution.

Abstract: The disclosure relates to a process for purifying crude, concentrated wet-processed phosphoric acid. To this end, the disclosure provides:(a) for the organic solvent to be mixed with the starting product in a ratio by volume of more than 4:1 to effect in a single process step the extraction--from the crude wet-processed phosphoric acid--of a quantity of phosphoric acid necessary for 40 to 70 weight % of the P.sub.2 O.sub.5 used to go into the organic phase, and for the resulting aqueous phosphoric acid raffinate to contain at most 28-32 weight % P.sub.2 O.sub.

Abstract: The disclosure relates to a process for removing organic compounds from wet-processed phosphoric acid with the aid of an adsorbant. To this end the disclosure provides for the acid to be heated to at least 250.degree. C. prior to treating it with the adsorbant. The disclosure also relates to an apparatus for carrying out the process.