Anode for electrolysis and manufacturing method thereof
View Patent ↗Subject The present invention aims to provide an anode for electrolysis by an ion exchange membrane process and the manufacturing method thereof which can show a lower concentration of by-product oxygen gas in chlorine gas and a lower overvoltage stably for a long time, compared with conventional anodes. Solution to Problem The present invention is to prepare an anode for electrolysis, comprising a substrate comprising titanium or titanium alloy and a plurality of coating layers provided by the thermal decomposition baking method on the surface of the substrate, wherein the coating layer comprises the first coating layer comprising a mixture of iridium oxide, ruthenium oxide and titanium oxide, provided on the surface of the substrate, the second coating layer comprising a mixture of platinum and iridium oxide, provided on the first coating layer, a unit layer comprising the first coating layer and the second coating layer, provided on the surface of the second coating layer by a single or a plurality of layer, and the second coating layer, provided on the outermost layer of the unit layer; the plurality of layer is provided on the surface of the substrate by means of the thermal decomposition baking method and the coating layer is followed by post-baking at a higher baking temperature than the formerly applied in the thermal decomposition baking method.
1. An anode for electrolysis, comprising:
a substrate comprising titanium or titanium alloy, and
a plurality of coating layer provided on the surface of the substrate by the thermal decomposition baking method,
wherein the coating layer comprising:
the first coating layer comprising a mixture of iridium oxide, ruthenium oxide and titanium oxide, provided on the surface of the substrate,
the second coating layer comprising a mixture of platinum and iridium oxide, provided on the first coating layer,
a unit layer comprising the first coating layer and the second coating layer, provided on the surface of the second coating layer by a single or a plurality of layer,
and the second coating layer, provided on the outermost layer of the unit layer,
characterized in that a plurality of coating layer is provided on the surface of the substrate by means of the thermal decomposition baking method, followed by post-baking at a baking temperature higher than that by the thermal decomposition baking method.
2. The anode for electrolysis according to claim 1 , wherein the baking temperature by the thermal decomposition baking method is 350 degrees Celsius˜520 degrees Celsius.
3. The anode for electrolysis according to claim 1 , wherein the post-baking temperature is higher than the temperature by the thermal decomposition baking method, to a temperature range of 475 degrees Celsius˜550 degrees Celsius.
4. The anode for electrolysis according to claim 1 , wherein the composition ratios of iridium, ruthenium and titanium of the first coating layer are in the range of 20˜30mol. % , 25˜30mol. %, and 40˜55mol. % , respectively.
5. The anode for electrolysis according to claim 1 , wherein the composition ratios of platinum and iridium of the second coating layer are in the range of 60˜80mol. % and 20˜40mol. %, respectively.
6. A manufacturing method of an anode for electrolysis provided with a plurality of coating layer on the surface of the substrate comprising titanium or titanium alloy by means of the thermal decomposition baking method, characterized in steps, comprising:
1) a step to prepare the first coating layer comprising a mixture of iridium oxide, ruthenium oxide and titanium oxide by coating a mixing solution of iridium compound, ruthenium compound and titanium compound on the surface of the substrate comprising titanium or titanium alloy by means of the decomposition baking method for heat-baking;
2) a step to prepare the second coating layer comprising a mixture of platinum and iridium oxide by coating a mixing solution of platinum compound and iridium compound on the surface of the first coating layer by means of the thermal decomposition baking method for heat-baking;
3) a step to prepare a single or a plurality of unit layer comprising the first coating layer and the second coating layer on the surface of the second coating layer by the thermal decomposition baking method;
4) a step to prepare the second coating layer on the outermost layer of the unit layer by the thermal decomposition baking method; and
5) a plurality of coating layer being subject to post-baking at a higher baking temperature than the temperature by the thermal decomposition baking method.
7. The manufacturing method of an anode for electrolysis according to claim 6 , wherein the baking temperature by the thermal decomposition baking method is in the range of 350 degrees Celsius˜520 degrees Celsius.
8. The manufacturing method of an anode for electrolysis according to claim 6 , wherein the post-baking temperature is higher than that by the thermal decomposition baking method, in the range of 475 degrees Celsius˜550 degrees Celsius.
9. The manufacturing method of an anode for electrolysis according to claim 6 , wherein the composition ratios of iridium, ruthenium and titanium of the first coating layer are in the range of 20˜30mol. % , 25˜30mol. %, and 40˜55mol. % , respectively.
10. The manufacturing method of an anode for electrolysis according to claim 6 , wherein the composition ratios of platinum and iridium of the second coating layer are in the range of 60˜80mol. % and 20˜40mol. %, respectively.