Abstract: A method is provided for zeolite synthesis from a synthesis medium containing in particular a trivalent aluminum source, a tetravalent silicon source, at least an alkaline or alkaline-earth cation in hydroxide form and water in a reactor containing a solid helical moving body in a guiding tube defining an internal space and a space external to the tube. The invention is characterized in that the synthesis medium is circulated in the reactor in a continuous flow passing through the internal space then the space external to the tube and returning to the internal space, only driven by the roation of the solid helical moving body, at a speed of less than 500 rpm, in the tube which is kept fixed, the synthesis medium being kept at a temperature suitable for at least one of the ripening operations or the crystal growth of the synthesized zeolite. The invention also is directed to a device for implementing the method.

Abstract: A process of preparing a powder of metal hydroxides based on nickel hydroxide for an electrode of an electrochemical cell having an alkaline electrolyte. The process includes introducing a solution of salts of nickel and of cobalt and of cadmium and/or zinc into a reactor in a slow and continuous manner under good stirring conditions, together with a strong base and an ammonium salt. Proportions of the ingredients are determined so that the pH of the mixture is stabilized at a value of 9.2.+-.0.1, and the temperature is maintained between 80.degree. C. and 85.degree. C. Particles metal hydroxide precipitated from the reaction are filtered, washed, and dried.