Process and apparatus for downward recycling of the electrolyte in diaphragm cells

DETAILED DESCRIPTION We claim: 1.
In the process of producing chlorine by electrolyzing aqueous alkali metal chloride solution in an electrolytic cell between a hollow anode located between a pair of cathode surfaces and open at its top and lower ends, the improvement which comprises generating between said cathode surfaces and said anode, during said electrolysis, upward circulation of solution toward the top of the solution in both the hollow interior of the anode and in the spaces between the exterior of the anode and the adjacent cathode surfaces, and downward movement of the solution from an upper level of said solution to a lower level thereof through electrically non-conducting passages substantially free of gaseous halogen within said hollow anode.
2.
The process of claim 1 wherein the downward flow is in a passage between said pair of anode surfaces which are not involved with the upward flow of chlorine bubbles generated at the anode.
3.
A process of electrolyzing a pool of an aqueous solution of alkali metal halide in an electrolytic cell to liberate gaseous halogen within said cell and form alkali metal hydroxide and hydrogen, which comprises conducting said electrolysis between a plurality of hollow anodes, open at their tops and lower ends, which have conductive surfaces facing a plurality of cathode surfaces, immersed in said pool and separated by a diaphragm, whereby to evolve gaseous halogen which rises in the solution in the interelectrodic gap between the anodes and cathodes and in the hollow interior of said anodes creating upward movement of the solution toward the top of said pool, flowing solution downward within said cell through electrically non-conducting passages substantially free of gaseous halogens in the interior of the anodes from an upper level to a lower level of said pool, and returning the downward flowing solution to said pool.
4.
The process of claim 3 wherein the halide is a chloride and the downward flow is conducted in a plurality of spaced passages, each passage being inside a different anode surface