Abstract: In a continuous process for the nitration of cellulose, a slurry of cellulose in nitrating liquor is injected under pressure into a primary nitration reactor by means of an injection pump, the reactor comprising a loop of tubing, the slurry is circulated in the loop by means of a circulation pump at a rate which is greater than the rate of injection in order to ensure that the slurry is vigorously agitated, the slurry is optionally transferred, successively, from the primary loop to one or more secondary nitration reactors, each of which also comprises a loop of tubing equipped with a circulation pump, and the slurry is withdrawn from the final loop and the nitrocellulose is recovered.

Abstract: A solid product impregnated with a liquid substance is subjected to successive washing operations in a washing zone by a process wherein:the successive washing operations are carried out with a washing liquid the content of the substance to be eliminated therein decreasing from the first washing operation towards the last washing operation;a small quantity of liquid rich in the substance to be eliminated is removed from the washing liquid used during the first washing operation and an equivalent amount of the liquid free of the substance to be eliminated is introduced into the washing liquid used during the last washing operation;during each washing operation a substantial quantity of washing liquid is used, the greater quantity of this liquid being recovered and with the exception of the first washing operation, a small quantity of this washing liquid is transferred into the washing liquid corresponding to the washing operation at the immediately lower level whereby the content of the substance to be elimina

Abstract: Dilute solutions of corrosive products, such as sulphuric or phosphoric acid, are concentrated by pre-concentrating the dilute solution and then introducing the pre-concentrated solution into a tunnel in which it flows in a thin layer over successive cascades while being heated, preferably by indirect radiant heating. An installation for carrying out the process is also described.