Abstract: A process for the preparation in an aqueous medium of purified calcium sulfate, with high whiteness, characterized in that it comprises:a) the formation of an aqueous solution by dissolution of impure hemihydrated calcium sulfate, at a concentration at most of 13.0 grams per liter (expressed in dissolved CaSO.sub.4) and at a pH of at least 5.

Abstract: Pollen suppressants of the formula ##STR1## wherein Z represents a divalent organic radical of the formula --CH.dbd.CH--CH.dbd.CH--, --CH.dbd.CH--CH.dbd.N--, --CH.dbd.CH--N.dbd.CH--, --CH.dbd.CH--NH--, --CH.dbd.CH--O--, or --CH.dbd.CH--S-- or said radical in which an H of Z is replaced with a halogen atom with the proviso that no more than three H of Z are replaced by fluorine; a C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 alkanoyl, cyano, nitro, hydroxy, or trihalomethyl group; or a group of the formula --NR.sup.1 R.sup.2 wherein R.sup.1 and R.sup.2 independently represent a hydrogen atom or a C.sub.1 -C.sub.4 alkyl group; Y is Y.sup.1 R.sup.3 or NR.sup.4 R.sup.5 wherein Y.sup.1 is oxygen or sulfur; R.sup.3 hydrogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxyalkyl, cyclohexylmethyl, halogenated C.sub.1 -C.sub.4 alkyl, phenyl, or benzyl; and R.sup.4 and R.sup.5 are independently selected from the group consisting of hydrogen, C.sub.1 -C.sub.4 alkyl, or C.sub.1 -C.sub.

Abstract: Pollen suppressants of the formula ##STR1## wherein Z represents a divalent organic radical of the formula --CH.dbd.CH--CH.dbd.CH--, --CH.dbd.CH--CH.dbd.N--, --CH.dbd.CH--N.dbd.CH--, --CH.dbd.CH--NH--, --CH.dbd.CH--O, or --CH.dbd.CH--S-- or said radical in which an H of Z is replaced with a halogen atom with the proviso that no more than three H of Z are replaced by fluorine; a C.sub.1 -C.sub.4 alkyl, C.sub.1 C.sub.4 alkoxy, C.sub.1 -C.sub.4 alkanoyl, cyano, nitro, hydroxy, or trihalomethyl group; or a group of the formula --NR.sup.1 R.sup.2 wherein R.sup.1 and R.sup.2 independently represent a hydrogen atom or a C.sub.1 -C.sub.4 alkyl group; Y is Y.sup.1 R.sup.3 or NR.sup.4 R.sup.5 wherein Y.sup.1 is oxygen or sulfur; R.sup.3 is hydrogen, C.sub.1 -C.sub.4 alkyl, C.sub.2 -C.sub.4 alkenyl, C.sub.2 -C.sub.4 alkynyl, C.sub.1 -C.sub.4 alkoxyalkyl, cyclohexylmethyl, halogenated C.sub.1 -C.sub.4 alkyl, phenyl, or benzyl; and R.sup.4 and R.sup.5 are independently selected from the group consisting of hydrogen, C.

Abstract: Pollen suppressants of the formula ##STR1## wherein Z represents a divalent organic radical of the formula --CH.dbd.CH--CH.dbd.CH--, --CH.dbd.CH--CH.dbd.N--, --CH.dbd.CH--N.dbd.CH--, --CH.dbd.CH--NH--, --CH.dbd.CH--O--, or --CH.dbd.CH--S-- or said radical in which an H of Z is replaced with a halogen atom with the proviso that no more than three H or Z are replaced by fluorine; a C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 alkanoyl, cyano, nitro, hydroxy, or trihalomethyl group; or a group of the formula --NR.sup.1 R.sup.2 wherein R.sup.1 and R.sup.2 independently represent a hydrogen atom or a C.sub.1 -C.sub.4 alkyl group; Y is Y.sup.1 R.sup.3 or NR.sup.4 R.sup.5 wherein Y.sup.1 is oxygen or sulfur; R.sup.3 is hydrogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxyalkyl, cyclohexylmethyl, halogenated C.sub.1 -C.sub.4 alkyl, phenyl, or benzyl; and R.sup.4 and R.sup.5 are independently selected from the group consisting of hydrogen, C.sub.1 -C.sub.4 alkyl, or C.sub.1 -C.sub.

Abstract: A pollen suppressant of the formula ##STR1## wherein R.sup.1 and R.sup.4 independently represent C.sub.1 -C.sub.4 alkyl, phenyl, naphthyl, or phenyl or naphthyl substituted with one to three substituents selected from the group consisting of halogen, trihalomethyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 alkyl, and cyano; R.sup.2 is ##STR2## where R.sup.5 is a C.sub.1 -C.sub.12 alkyl group, optionally substituted with one or more halogen atoms, or an aryl group selected from the group consisting of 6-membered rings containing 0-3 nitrogens and fused bicyclic 10-membered rings containing 6 atoms in each ring and 0-3 nitrogens per ring with the remaining atoms in the ring or rings of said aryl group being carbon atoms, said aryl group being optionally substituted with a C.sub.1 -C.sub.4 alkyl group or an electron-withdrawing group, R.sup.3 is hydrogen, a halogen a C.sub.1 -C.sub.4 alkyl group, a carboxy group or an agronomically acceptable alkali metal salt thereof, or a group of the formula --COOR.sup.

Abstract: Cement clinker is produced in that raw cement powder is preheated in a suspension-type heat exchanger and is de-acidified in a fluidized bed and clinkered in a rotary kiln, and the clinker is subsequently cooled. A de-acidification of at least 95% is effected at a temperature above 850.degree. C. in a circulation system comprising a fluidized bed reactor, a cyclone separator and a recycling duct. The carbonaceous fuel required for the calcining and clinkering processes is fed in an amount of at least 65% (related to the total heat requirement) to the de-acidifying fluidized bed reactor and in an amount of at least 10% (related to the total heat requirement) to the clinkering rotary kiln.The fuel supplied to the de-acidifying fluidizing bed reactor is burnt near stoichiometrically in two stages with fluidizing gas and secondary gas. The ratios of the rates and volumes of fluidizing gas to secondary gas are so selected that a mean suspension density of 100 to 300 kg/m.sup.

Abstract: Cement clinker is produced in that raw cement powder is preheated in a suspension-type heat exchanger and is de-acidified in a precalcining apparatus and clinkered in a fluidized bed and the clinker is subsequently cooled. An de-acidification of at least 95% is effected at a temperature above 85.degree. C. in a circulation system comprising a fluidized bed reactor, a cyclone separator and a recycling duct. The carbonaceous fuel required for the calcining and clinkering processes is fed in an amount of at least 65% (related to the total heat requirement) to the de-acidifying fluidized bed reactor and in an amount of at least 10% (related to the total heat requirement) to the clinkering fluidized bed reactor. The fuel supplied to the fluidizing bed reactor is burnt near stoichiometrically in two stages with fluidizing gas and secondary gas. The ratios of the rates and volumes of fluidizing gas to secondary gas are so selected that a means suspension density of 100 to 300 kg/m.sup.

Abstract: A device for mixing by turbulence gaseous fluids and solid particles placed in suspension, comprising a mixing chamber into which emerge a first flow of gas introduced through an inlet located at one end of the chamber and forming a vortex which is exhausted through an outlet volute, and a second axial flow introduced through the other end and penetrating along the axis of the vortex in order to mix there with the first flow, the whole being exhausted through the outlet volute. The outlet volute is located in the central portion of the mixing chamber, the latter comprising an upper portion for the formation of the vortex between the outlet volute and the inlet for the vortex flow (A), located at the upper end of it, and a lower portion for recovery and recycling of the solid particles, in the form of a sloping surface which widens upwardly from the inlet orifice for the axial flow (B), located at the lower end of the chamber, as far as the outlet volute.