Abstract: Barium sulfate particles having an average particle diameter d50 of from 0.1 to 10 ?m which are produced by precipitation can be dispersed better if they are covered with at least one organic additive.

Abstract: Barium sulfate particles having an average particle diameter d50 of from 0.1 to 10 ?m which are produced by precipitation can be dispersed better if they are covered with at least one organic additive.

Abstract: Barium sulfate particles having an average particle diameter d50 of from 0.1 to 10 &mgr;m which are produced by precipitation can be dispersed better if they are covered with at least one organic additive.

Abstract: Barium sulfate particles having an average particle diameter d50 of from 0.1 to 10 &mgr;m which are produced by precipitation can be dispersed better if they are covered with at least one organic additive.

Abstract: The invention relates to a process for separating N-methyl-2-pyrrolidone (NMP) from aqueous solutions which are obtained in industry, inter alia, in the production of heat-resistance polymers such as polyamides and polyimides.According to the invention, the extractants used are phenols which are sparingly soluble in water, are aliphatically monosubstituted and/or polysubstituted in the nucleus and have 4 to 16 carbon atoms in the straight-chain or branched, saturated or unsaturated aliphatic radical and have a boiling point which is preferably at least 20.degree.-25.degree. C. above the boiling point of NMP. If necessary, an inert, viscosity-reducing diluent is added.

Abstract: A process for continuous rectification of a liquid mixture containing alcohols, particularly a liquid fermate, employs a plurality of distillation columns to which the liquid mixture is fed in parallel, and which have successively reduced operating pressures and temperatures from an initial one to a final one thereof. The top vapor distillate from the higher-pressure columns supplies driving heat to the sumps of the next successively lower-pressure columns. Direct steam at 130.degree. C. to 160.degree. C. is fed to the sump of the column operated at the highest pressure. Direct steam is generated by indirect heat exchange of water with the top vapor withdrawn from the columns, and the resulting direct steam is fed to the sumps of the next-lower-pressure columns. The apparatus can also include a section for the production of absolute alcohol.