Abstract: A method of determining nitrogen in various nitrogenous materials, wherein the materials are combusted by being brought into contact with a solid metallic catalytic mass, in the presence of an oxygenated gas, so as to convert the nitrogen into NO. This is then determined, preferably by chemiluminescence or by optical interferometry. The method is improved by adding a halide of an alkali metal or an alkaline earth metal to the materials prior to combustion.An apparatus comprising an oven (1,2,2') charged with catalytic mass (4), which can be a wire acting as a heating element, and provided with an oxygen inlet (6). The catalytic mass is a non-oxidizable ferrous alloy or a metal of the Pt group.

Abstract: The invention is an improved catalytic process for removing H.sub.2 S and sulfanes from liquid sulfur and a catalyst system for carrying out the process. The catalyst comprises a basic component and a surfactant component.

Abstract: A device for regulating the operation of a chemical treatment plant, by attenuation of the variances of the regulating parameters, has a calculation circuit connected to a measuring device for measuring flows of compounds at the input of the plant and measuring devices for measuring the contents of residual input compounds still present at the output of the plant. The calculation circuit performs coherence processings of the measured values to attenuate the variances of these values. The measurement provides a set-point signal which is used for the regulation of the plant.

Abstract: The invention is an improved catalytic process for removing H.sub.2 S and sulfanes from liquid sulfur and a catalyst system for carrying out the process. The catalyst comprises a basic component and a surfactant component.

Abstract: Bitumen-polymer compositions are prepared, by mixing, at between 130.degree. C. and 230.degree. C., a bitumen with a styrene and conjugated diene copolymer and a sulphur source, the copolymer and the sulphur source being added to the bitumen either directly, or in the form of a mother solution in a hydrocarbon oil, then by maintaining the whole under stirring at between 130.degree. C. and 230.degree. C. for at least fifteen minutes.By way of sulphur source is used 0.005 to 15% by weight, with respect to bitumen, one or several polymeric or not, cyclic or linear polysulphides, and especially ditertiododecyl or dinonyl pentasulphide. The bitumen-polymer compositions obtained can be used for the obtention of superficial road coverings and present a constant quality of its properties.

Abstract: Process of enrichment of minerals by flotation by means of a collector comprising a thio-compound, the thio-compound being a straight or branched dialkyl or dialkenyl polysulphide.

Abstract: Bitumen-polymer compositions are prepared, by mixing, at between 130.degree. C. and 230.degree. C., a bitumen with a styrene and conjugated diene copolymer and a sulphur source, the copolymer and the sulphur source being added to the bitumen either directly, or in the form of a mother solution in a hydrocarbon oil, then by maintaining the whole under stirring at between 130.degree. C. and 230.degree. C. for at least fifteen minutes. By way of sulphur source is used 0.005 to 15% by weight, with respect to bitumen, one or several polymeric or not, cyclic or linear polysulphides, and especially ditertiododecyl or dinonyl pentasulphide. The bitumen-polymer compositions obtained can be used for the obtention of superficial road coverings and present a constant quality of its properties.

Abstract: A process for automated regulation of a unit producing sulphur by oxidation of hydrogen sulphide, in which the flow of gas carrying oxygen into the unit is regulated so as to keep an operating parameter, based on measurement of the sulphurous compound of the residual gases, level with a reference value.It is characterized by the fact that the control signal, used to regulate the flow of gas containing oxygen at the unit inlet, is a combination of a signal based on measurements taken at the inlet, and representing the theoretical flow of this gas needed to keep the operating parameter at its reference level and another signal representing the correction needed in this flow to adjust the instantaneous value of the parameter to the reference level.This process allow better control of the sulphur unit, with increased efficiency and reduced atmospheric pollution.

Abstract: A process for automated regulation of a unit producing sulphur by oxidation of hydrogen sulphide, in which the flow of gas carrying oxygen into the unit is regulated so as to keep an operating parameter, based on measurement of the sulphurous compound of the residual gases, level with a reference value.It is characterized by the fact that the control signal, used to regulate the flow of gas containing oxygen at the unit inlet, is a combination of a signal based on measurements taken at the inlet, and representing the theoretical flow of this gas needed to keep the operating parameter at its reference level and another signal representing the correction needed in this flow to adjust the instantaneous value of the parameter to the reference level.This process allow better control of the sulphur unit, with increased efficiency and reduced atmospheric pollution.