Hoechst Aktiengesellschaft

Gerhard Edelmann

Hans Millauer

Friedrich Rosenstock

Heinz Muller

Bernhard Rauxloh

The invention relates to a process for separating off polyester plastics from a mixture of polyester, polyvinyl chloride and, if present, other plastics, wherein in the flotation the polyester remains as the residue and the polyvinyl chloride and, if present, other plastics are recovered in floated form, which comprises treating the mixture of plastics with an aqueous alkaline solution and separating off the polyester from polyvinyl chloride and, if present, other plastics by flotation.

Process for the separation of plastics by flotation

An improved process for concentrating and dewatering of mineral suspensions by filtration which comprises adding to the suspension prior to the filtration as filter aid a composition containing a sulfosuccinate of the formula I ##STR1## wherein R.sup.1 and R.sup.2 each are an alkyl radical having about 6 to 12 carbon atoms and Me is an alkali metal, and an aliphatic amine having at least 5 carbon atoms.

Dewatering of mineral suspensions

Process for the preparation of thiocarbamic acid-O-esters of the general formula ##EQU1## in which R.sub.1 means an alkyl or cycloalkyl radical, R.sub.2 and R.sub.3 each stands for an alkyl radical which may be substituted by one of the groups --(O--C.sub.2 H.sub.4).sub.n --OH, --(OC.sub.2 H.sub.4).sub.n --OCH.sub.3 or --O--(CH.sub.2).sub.m --CH.sub.3, n being 0, 1 or 2 and m being 1 or 2, or stand for a cycloalkyl radical, and one of the radicals R.sub.2 and R.sub.3 may be hydrogen which process comprises reacting at a temperature ranging between 20.degree. and 120.degree.C in an aqueous or water-containing medium a xanthogenate of the formula ##EQU2## in which R.sub.1 is defined as above and Me is an alkali metal with a primary or secondary aliphatic amine of the formula ##EQU3## in which R.sub.2 and R.sub.3 are defined as above, and elementary sulfur.

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Hofheim am Taunus, Germany

Gerhard Edelmann