Welding method for cathode netted bag of electrolyzer

Abstract

The welding process of netted cathode bag for electrolyzer with metal anode including positioning and pressing the conducting grid plate inside the wire net bag; extending the special welding rod via the wire net bag to weld the conducting grid plate and the wire net bag together. The said special welding rod is one of several welding rods in the diameter not greather than 4 mm and connected together via gas welding. The said welding process forms no notch to the surface of and no blocking in the wire net bag, and this is favorable to adsorption of the diaphragm.

Description

1. Technical field: [0001] The invention relates to a welding method for a cathode mesh bag of an electrolytic cell, in particular to a welding method for a cathode mesh bag of a metal anode electrolytic cell used in the chlor-alkali chemical industry. 2. Technical background: [0002] At present, the cathode mesh bag used as a metal anode electrolyzer in the chlor-alkali chemical industry is composed of a wire mesh and a conductive grid. Specifically, a hexahedral mesh bag is made of a wire mesh, and a conductive grid is placed in the wire mesh bag. The wire mesh and the conductive grid are connected. Fixing is by direct resistance welding on the membrane adsorption surface of the wire mesh; thus leaving pits on the membrane adsorption surface of the wire mesh, if the diameter of the resistance welding head is greater than 8mm, it is easy to cause the wire mesh around the welding point to block the holes ; Now the production requirements for mesh bags are: the surface uneve...

AI Technical Summary

Problems solved by technology

[0002] At present, the cathode mesh bag used as a metal anode electrolyzer in the chlor-alkali chemical industry is composed of a wire mesh and a conductive grid. Specifically, a hexahedral mesh bag is made of a wire mesh, and a conductive grid is placed in the wire mesh bag. The wire mesh and the conductive grid are connected. Fixing is by direct resistance welding on the membrane adsorption surface of the wire mesh; thus leaving pits on the membrane adsorption surface of the wire mesh, if the diameter of the resistance welding head is greater than 8mm, it is easy to cause the wire mesh around the welding point to block the holes ;Now the production requirements for mesh bags are: the surface unevenness is not greater than 1mm, the unevenness is not greater than 1 / 1000, and the solder joints shall not be greater than 4 meshes, otherwise it is necessary to drill holes at the larger solder joints

Because the current welding method inevitably causes unevenness and hole blocking on the membrane adsorption surface of the wire mesh, when the membrane is adsorbed by the mesh bag, it will cause uneven adsorption of the membrane on the surface of the wire mesh, and pits will be formed on the surface after the membrane is adsorbed and formed. There will also be difficulties in the adsorption of the diaphragm at the welded part of the barbed wire mesh with plugged holes.

Due to the above defects, during the production and use of chlor-alkali, the permeability of the cathode will be uneven, so that the hydrogen content of chlorine in the electrolytic cell is greater than or equal to 2% and the concentration of NaOH is low.