Abstract: The invention relates to a process for separating seminoble metals or noble metals from aqueous solutions having compounds of these metals dissolved therein, by reaction with yellow phosphorus. More particularly the aqueous solutions are contacted with carrier material having a yellow phosphorus coating applied thereto.It is possible for the aqueous solutions to be conveyed through a zone having the yellow phosphorus-coated carrier material placed therein, and for them to be subsequently conveyed through a further zone having uncoated carrier material placed therein.

Abstract: The disclosure relates to a process for the continuous dearsenification of polyphosphoric acid with the aid of hydrogen sulfide in a gas admission zone. To this end, the disclosure provides for the acid to be dearsenified in a gas admission zone subdivided so as to comprise at least two separate liquid matter-receiving zones, each zone being separated from the other by means of a separate gas zone; for the liquid in each of the liquid matter-receiving zones to be maintained at a level 0.

Abstract: The invention relates to a process for making long chain ammonium polyphosphate consisting essentially of crystalline modification II. To this end, a mixture of phosphorus pentoxide and ammonium orthophosphate in a molar ratio of 1:0.9 to 1:1.1 is reacted with 0.1 to 15 mol % of melamine or its condensation products selected from melam, melem or mellon, calculated as melamine, at a temperature within the range 50.degree. to 150.degree. C. in the presence of an excess of ammonia and the reaction product is heat-treated at temperatures within the range 200.degree. to 400.degree. C.

Abstract: The invention relates to a process for making granulated, partially or completely hydrated alkali metal diphosphates or triphosphates. To this end, the invention provides for alkali metal diphosphates or triphosphates which consist to an extent of at least 20% of particles with a size of less than 0.045 mm and are hydrated to an extent of less than 90%, based on the phosphates' theoretical content of water of hydration, to be intensively mixed and granulated in the presence of water and an ammonium polyphosphate, this latter being used in a proportion of about 0.5 to 50 weight %, based on the quantity of water used.

Abstract: The invention relates to a process for separating seminoble and/or noble metals from an aqueous solution having compounds of these metals dissolved therein by subjecting the solution to reaction with red phosphorus. More particularly, the solution is conveyed through a zone containing a layer of granular red phosphorus particles with a size of 0.01 to 10 mm, which may be used in admixture with active carbon.

Abstract: The invention relates to a process for making aqueous alkali metal phosphate solutions by subjecting aqueous alkali metal phosphite solutions to catalytic oxidation with oxygen or air. More particularly, oxygen or air in stoichiometric excess proportions is introduced into the aqueous alkali metal phosphite solution at about 30.degree. to 110.degree. C., at a pH-value of 0 to about 8, and in the presence of SiO.sub.2 or aluminum silicate containing at most 10 weight % Al.sub.2 O.sub.3, for as long as necessary to achieve conversion of the alkali metal phosphite to alkai metal phosphate. After completion of the oxidation, the aqueous solution is separated from the catalyst.

Abstract: The present invention relates to a process for the oxidation of alkali metal phosphites to alkali metal phosphates at temperatures of between 400.degree. and 500.degree. C. To this end, alkali metal phosphites are employed in the form of an aqueous solution or suspension and, if necessary, the alkali metal : P atomic ratio in this feed material is adjusted to a ratio which at least corresponds to the atomic ratio desired for the final product.More particularly, the solution or suspension is spray-dried in a tower, in a single operational stage, by spraying in a flame zone. Starting material free from alkali metal phosphate and with an alkali metal : P atomic ratio equal to or greater than 3.5 is used for making a trialkali metal phosphate which is obtained in admixture with an alkali metal hydroxide. Starting material which contains from 25 to 45% by weight of alkali metal phosphate, calculated as phosphorus, based on their total phosphorus content, is employed for making alkali metal polyphosphates.

Abstract: Phosphorus in vapor form and phosphanes are separated from gas mixtures which consist of carbon monoxide, with or without hydrogen, nitrogen and steam. Concerned are more particularly the off-gases of phosphorus-producing furnaces. To this end, the gas mixture is admixed with at least the stoichiometric amount of oxygen and/or of oxygen-containing gases necessary to achieve conversion of the total phosphorus contained in the gas mixture to oxidation level V. The resulting mixture is introduced into a reaction zone maintained at a temperature within the range 200.degree. to 700.degree. C. and allowed to remain therein over a period of 0.5 to 20 seconds. Resulting phosphorus-V compounds are finally separated from the gas mixture.

Abstract: The invention relates to a process for making an isomeric mixture of secondary phosphines with the summation formula C.sub.20 H.sub.27 P. To this end, hydrogen phosphide is reacted with dicyclopentadiene in the presence of an agent yielding free radicals. More specifically, hydrogen phosphide and dicyclopentadiene are used in a molar ratio of 1 to at least 2 and the reaction is effected under a pressure of 5 to 90 bars. The mixture is used in the production of flotation aids and as an ingredient of catalytically active transition metal complexes.

Abstract: The invention relates to a process for making a finely dispersed, sparingly soluble salt of an oxyacid of phosphorus, having a maximum particle size of 20 .mu.m, by reacting a compound of a divalent metal with the oxyacid of phosphorus or an alkali metal or ammonium salt thereof. More particularly, finely dispersed salt consisting to an extent of at least 90% of particles with a size between 0.05 and 7 .mu.m is made. To this end, an at least 5% by weight aqueous solution or suspension of a compound of a divalent metal selected from the group Mg, Ca, Sr, Ba, Mn, Zn, Cu, Cd, Pb, Sn, Co and Ni is reacted, while maintaining a pH range of between 3 and 9 and while stirring, with an at least 2 mol % solution of at least one trivalent metal selected from the group Al, Fe and Cr in the oxyacid of phosphorus and, optionally, with an aqueous solution of an alkali metal or ammonium salt of the oxyacid of phosphorus, and the precipitated salt is separated off and dried.

Abstract: The invention relates to an apparatus for making red phosphorus by subjecting molten yellow phosphorus to a thermal conversion reaction in a closed reaction zone. To this end, a hollow shaft-provided and closed ball mill is preheated to a reaction temperature within the range 280.degree. to 590.degree. C. Yellow phosphorus is continuously introduced into the ball mill through the hollow shaft in quantities per unit time which permit the reaction temperature prevailing inside the ball mill to be maintained without supply of heat from the outside. More particularly, decreasing quantities of yellow phosphorous are introduced per unit time at increasing temperature and increasing quantities of yellow phosphorus are introduced per unit time at decreasing temperature within the limits specified. Red phosphorus is allowed to cool inside the ball mill, water is poured over it and the whole is subjected to wet-grinding. An aqueous suspension of red phosphorus is finally removed from the ball mill.

Abstract: The invention relates to a process for the removal of metals, especially of iron and/or nickel and/or vanadium or their compounds, from carbon black. To this end, the invention provides for an aqueous carbon black suspension to be heated to a temperature of about 30.degree. to 90.degree. C., for chlorine to be passed therethrough with agitation. The chlorine gas is used in a stoichiometric excess, based on the metal content of the aqueous carbon black suspension. Next, the carbon black is separated from the aqueous suspension and dried.

Abstract: The invention relates to the production of phosphorus-containing anticorrosive pigments with a particle size of at most 20 microns by reacting one or more calcium or magnesium compounds with phosphoric acid or acid alkali metal or ammonium phosphates by intimately mixing an aqueous suspension or solution of the reactants inside a dispersing means rotating at a speed of 3000 to 10,000 rpm. More particularly, fine pulverulent calcium and magnesium compounds are converted, with agitation, together with water and, if desired, a water-soluble alkanol to a homogeneous suspension or solution. The suspension or solution is intimately mixed, inside the dispersing means at 0.degree. to 40.degree. C. and in an approximately stoichiometric ratio, with the phosphoric acid or acid phosphate solution. Resulting and precipitated pigment is separated and dried under mild conditions while maintaining its content of water of crystallization.

Abstract: The invention relates to a process for making phosphorus-containing anticorrosive pigments having a size of at most 20 microns by reacting one or more compounds of magnesium, calcium, strontium, barium, zinc, aluminum, iron, chromium or manganese with an oxygen acid of phosphorus or its alkali metal or ammonium salts at temperatures within the range 10.degree. to 100.degree. C. More particularly pigments consisting to an extent of at least 90% of particles with a size between 0.05 and 8 microns are produced by introducing an aqueous suspension or solution of the reactants into a dispersing means rotating at a speed of 3000 to 10,000 rpm, reacting the reactants by intimately mixing them, and separating and drying precipitated pigment.

Abstract: The invention relates to a process for freeing aqueous phosphoric acid solutions from organic contaminants. To this end, the solutions are admixed and reacted with hydrogen peroxide in the presence of a catalyst consisting of a noble metal or metal oxide being inert with respect to phosphoric acid or of a mixture of said noble metal and metal oxide.

Abstract: The invention relates to a process for making aqueous phosphorous acid solutions by admixing an aqueous sodium phosphite solution with hydrochloric acid. More specifically, phosphorous acid solutions substantially free from sodium in hydrochloric acid are produced by introducing hydrogen chloride, into the sodium phosphite solution until the latter is saturated therewith and separating precipitating sodium chloride from the resulting phosphorous acid solution in hydrochloric acid.

Abstract: The invention relates to a process for making red phosphorus by subjecting molten yellow phosphorus to a thermal conversion reaction in a closed reaction zone. To this end, a hollow shaft-provided and closed ball mill is preheated to a reaction temperature within the range 280.degree. to 590.degree. C. Yellow phosphorus is continuously introduced into the ball mill through the hollow shaft in quantities per unit time which permit the reaction temperature prevailing inside the ball mill to be maintained without supply of heat from the outside. More particularly, decreasing quantities of yellow phosphorus are introduced per unit time at increasing temperature and increasing quantities of yellow phosphorus are introduced per unit time at decreasing temperature within the limits specified. Red phosphorus is allowed to cool inside the ball mill, water is poured over it and the whole is subjected to wet-grinding. An aqueous suspension of red phosphorus is finally removed from the ball mill.

Abstract: The invention relates to the continuous production of phosphine. To this end, elemental phosphorus is reacted with an aqueous alkali metal hydroxide solution and at least one alcohol, the reactants being used in admixture with 0.01 to 2 weight % of a surfactant, the percentage being based on the alcohol.

Abstract: Wet-processed phosphoric acid is purified by counter-current extraction with the use of an organic solvent, in which water is partially soluble and which is capable of absorbing phosphoric acid, the organic phosphoric acid extract is separated from residual wet-processed phosphoric acid, unabsorbed by the solvent, and phosphoric acid is recovered from the separated organic phosphoric acid extract. More specifically, the wet-processed phosphoric acid is extracted with the use of a solvent containing more than 0 and less than 50% of water, based on the saturation concentration, and a mineral acid in a quantity corresponding to the quantity, in moles, of cation-bound phosphate in the crude acid.

Abstract: Wet-processed phosphoric acid is decontaminated. To this end, the phosphoric acid and an organic solvent, which is partially miscible with water and capable of absorbing phosphoric acid, are contacted countercurrently with respect to one another. The resulting organic phosphoric acid solution is separated from contaminants unabsorbed by the solvent, termed primary raffinate, decontaminated phosphoric acid is recovered either in the form of free acid by re-extracting the organic phosphoric acid solution with water, or in the form of an alkali metal phosphate by reacting the organic phosphoric acid solution with an alkali, and the primary raffinate is treated countercurrently with a solvent containing a mineral acid.