The invention relates to a construction for ventilation of hydrogen gas comprising at least a first metallic layer (1), sensitive to hydrogen embrittlement, a second (2) metallic layer, and a mesh (4), wherein the first layer (1) is joined to the second layer (2), and said mesh (4), forming venting channels (5) through which channels (5) hydrogen can be vented, is joined to, and in between, said first (1) and second (2) metallic layers. The invention further concerns a method for production thereof.

The invention relates to a method of producing pulp comprising a step of forming green liquor containing alkali metal sulfide and alkali metal carbonate. The method further comprises a step of electrochemically treating the green liquor to oxidize at least part of the sulfide therein.

Sulphide-containing white liquor is treated in a continuously operating electrolytic cell having separate anode and cathode compartments separated by a partially permeable barrier. White liquor is introduced into the anode compartment of the cell, and an aqueous solution of alkali metal hydroxide is introduced into the cathode compartment of the cell so that sulphide is oxidized in the anode compartment, while at the same time alkali metal cations are transported through the barrier into the cathode compartment, where water reacts to form hydroxide ions. An electrolytic cell suited for implementing the method is also disclosed.