Abstract: A method for manufacturing fine mineral powders using systems that include one or more air classifiers, dust separators like cyclones and/or filters, at least one ventilator and instruments connecting tubes or pipes for the transport of air. The relative humidity of air in the air classifier is kept in a range between 15% to 35%.

Abstract: Method for manufacturing fine mineral powders using systems, consisting of one or more air classifier, dust separators like cyclones and/or filters, at least one ventilator as well as these instruments connecting tubes or pipes for the transport of air. The invention is characterised by keeping the relative humidity of the classifier air in the air classifier in a range between 15% to 35%.

Abstract: A process for the removal of alkyl halides from a liquid hydrocarbon substrate by reaction of the halides with an isoalkane and/or aromatic hydrocarbons in the presence of an acid catalyst supported on a solid support material.

Abstract: A process for the manufacture of a hydrocarbon mixture being rich in middle distillate products with the boiling part range of 175.degree.-360.degree. C. by alkylation of a hydrocarbon feed stock with an olefinic alkylating agent, comprises the steps of contacting a hydrocarbon feedstock and an olefinic alkylating agent with a catalyst composition containing an acid selected from the group of fluorinated alkane sulphonic acids having the general formula: ##STR1## wherein R'=F, Cl, Br, I, H, an alkyl or perfluoro alkyl group,R"=H, alkyl, aryl or a perfluoro alkoxy group, andrecovering a product stream of alkylated hydrocarbons and optionally recycling to the reactor lower isoalkanes being formed during the alkylation.