GB833759A - Electrolytic cellulose recovery apparatus - Google Patents

Abstract

833,759. Electrolysis. ESTES, J. F. Oct. 2, 1956, No. 29935/56. Class 41. An electrolytic cell for recovering cellulose from a solution has a removable anode 25 comprising a rectangular metal plate, e.g. of iron, and members 26, 27 engaging each side edge and the bottom edge of the plate, the members 26, 27 having portions projecting normally from opposite faces of the plate. The members 26, 27 may be of hard rubber. The plate 25 has a hole 28 for receiving a hook whereby the anode is removably suspended in the cell, and the member 27 at the lower edge of the anode 25 acts as a baffle for solution entering the bottom of the cell. The members 26 engage vertical slots in the end walls of the cell. Copper cathodes are fixed to each end wall. A number of cells are connected for circulation of solution in series through them, solution entering at the bottom and leaving at the top of each cell which has an outlet at the top for gas, e.g. ammonia, which is led therefrom to a tank which is connected to a solution supply tank in the circuit, whereby ammonia is reintroduced into the solution. Fresh solution is delivered to the supply tank to regenerate the electrolyte. A pump and valves may be included in the circuit. The electrolyte is formed by dissolving a cellulosic material in a solution formed by mixing a saturated solution of a metal salt, e.g. copper sulphate containing ammonium chloride, with a concentrated sodium hydroxide solution, and dissolving the resultant precipitate in a solution of ammonium hydroxide. Voltages of 2 to 12 are employed at an anode current density of 5 to 20 amps per sq. foot, and periodically reversed D.C. with or without A.C. may be employed. U.S.A. Specification 2,743,220 is referred to.