Abstract: Aqueous solutions which are contaminated by hydrogen sulfide, hydrogen cyanide, and ammonia are brought to a pH of about 3 or less after their formation and treated with an inert gas in a stripping column to remove the sulfide and cyanide. The pH of the solution is then increased to about 10 or more and the solution is again treated with an inert gas in a second stripping column to remove the ammonia.

Abstract: A process is described for the polymerization of ethylene or copolymerization of ethylene with a C.sub.3 to C.sub.15 alpha olefin in solution, suspension or in the gas phase at 20.degree. to 250.degree. C. and 1 to 100 bars in the presence of a mixed catalyst comprising a separately produced halogen-containing titanium(III) compound and an organoaluminum compound while controlling the molecular weight with oxygen, wherein a mixture of organoaluminum compounds is employed comprising a halogen-containing aluminum alkyl and a trialkyl aluminum compound in a molar ratio of 1:0.05 to 1:20, the combined amount of organoaluminum compounds being present in an amount of 0.01 to 20 moles per one mole of halogen-containing Ti(III) compound.

Abstract: An improvement in a process for the preparation of an ethylene homopolymer or a copolymer of ethylene with an .alpha.-olefin containing 3 to 15 carbon atoms by contacting the monomer or mixture of monomers in solution, suspension or in gas phase at 20.degree. to 250.degree. C. at a pressure of 1 to 50 bar with a mixed catalyst comprising a chlorine containing titanium (III) compound and an organoaluminum compound in the presence of hydrogen, the improvement residing in employing as the organoaluminum compound a trialkylaluminum compound in an amount of 0.1 to 20 mol per mol titanium (III) compound and including in the polymerization mixture oxygen at a concentration of 0.001 to 0.1 volume percent based upon the amount of ethylene. By carrying out the polymerization by including oxygen in the polymerization reaction mixture and employing trialkylaluminum compound as the organoaluminum compound the mean molecular weight of the polymer can be regulated while obtaining a desired molecular weight distribution.

Abstract: A high molecular weight copolymer of ethylene and a C.sub.3 -C.sub.20 .alpha.-olefin which, after being molded at room temperature and pressure-free tempered at 120 to 250.degree. C. and thereafter cooled, provides molded articles having an ultimate tensile strength of more than 200 kg per square centimeter measured at 120.degree. C. and an impact strength of more than 200 kg cm/cm.sup.2 measured at 23.degree. C.; a process for the preparation of such a copolymer by a Ziegler catalysis which process is characterized in that the catalyst which is employed is one obtained by reducing a titanium-(IV)-halide with an organo-aluminum compound in an inert solvent such that the concentration of titanium-(III)-halide so formed amounts to 30 to 200 m mol/liter solvent, the C.sub.3 -C.sub.20 .alpha.-olefin is employed in an amount of 0.05 to 5 weight percent based upon the weight of the ethylene and the catalyst is either initially contacted with C.sub.3 -C.sub.20 .alpha.

Abstract: Optical wedge filter comprising a coloured gelatine layer on a flexible transparent support and a flexible transparent covering foil bonded the gelatine layer wherein the thickness of the coloured gelatine layer increases stepwise or continuously.