Abstract: A method and apparatus for continuous oxygen bleaching of cellulosic pulp is provided utilizing first and second pressurized chambers with a number of tubes in fluid communication with both of first and second chambers. Oxygen bearing fluid is intimately mixed with digested cellulosic pulp and is continuously fed under pressure to the first chamber. Communication is selectively provided between the first and second chambers through at least one of the tubular members to allow passage of pulp from the member to the second chamber. The tubular member through which pulp flows to the second chamber is progressively changed as are the members through which passage is blocked, so that the pulp remains within each tubular member sufficient time to allow oxygen-bleaching thereof without degradation, and passes through the members without channelling. The oxygen bleached pulp is continuously discharged from the second chamber. The passage of pulp through the tubular members may either be downwardly or upwardly.

Abstract: Apparatus for calcining wet powdery gypsum which comprises:(A) a furnace which generates a hot gas having a temperature higher than 900.degree.

Abstract: A single-stage reactor in the form of two concentric tubes and, one acting as a central stack and the other as a wall of reactor, widening out towards the top; a gas diffuser at the bottom of the stack, enabling gas to be injected into the liquid column above the diffuser, while a vesicle remover is located in the upper part of reactor; pipes and for feeding in the reagents, and a pipe for forcing back the gaseous phase at the top of reactor; a connection inclined by over 45.degree. to an extension of the horizontal and establishing direct communication between the bottom of reactor and a decanting chamber; and a vertical degassing tube located between connection and decanting chamber.Application of this arrangement to the reaction between finely divided aluminum, hydrogen and at least one olefin having 2 to 30 carbon atoms, at a temperature of from 100.degree. to 200.degree. and a pressure of 30 to 200 bars, in a perfectly homogeneous medium for the preparation of alkylaluminums.